[top]
000
FXUS61 KRNK 151154
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
654 AM EST THU JAN 15 2009
.SYNOPSIS...
ARCTIC AIR BEHIND A COLD FRONT WILL CONTINUE TO INFILTRATE THE
REGION DURING THE DAY...BRINGING WITH IT THE COLDEST AIR OF THE
SEASON THROUGH THE END OF THE WEEK. GUSTY WINDS WILL RESULT IN
DANGEROUS WIND CHILLS AT TIMES THROUGH FRIDAY...AND SOME SNOW
ACCUMULATION WITH BLOWING SNOW IS EXPECTED ALONG WESTERN MOUNTAIN
SLOPES THROUGH TONIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AFTER THE 15-18Z TIME FRAME THE 850 MB WINDS DROP BELOW 35 KNOTS AND
PRESSURE RISES ARE NOT AS LARGE DURING THE AFTERNOON. WILL CONTINUE
THE WIND ADVISORY IN GRAYSON COUNTY AND THE NORTHWEST NORTH CAROLINA
MOUNTAINS THROUGH NOON TODAY.
AT 09Z THE ARCTIC COLD FRONT WAS JUST PASSING THROUGH ROANOKE AND
MOVING EAST ACROSS THE BLUE RIDGE. THE FRONT WILL BE WELL THROUGH
THE ENTIRE COUNTY WARNING AREA BY 12Z. SURFACE TEMPERATURES WILL
BE STEADY OR WILL SLOWLY FALL TODAY AS 850 MB TEMPERATURES DROP
INTO THE -15 TO -20 RANGE BY 00Z. HOURLY TEMPERATURES WILL REFLECT
AN ATYPICAL DIURNAL TREND TODAY.
AT TIME MOMENT LOW LEVEL MOISTURE IS DEEP ENOUGH ALL THE WAY SOUTH
INTO NORTH CAROLINA FOR SNOW SHOWERS TO CONTINUE THROUGH THE
MORNING. BUT THE LOCAL WRF IS SHOWING SOME DECENT SUBSIDENCE AND
DRYING ALONG THE LEE SIDE OF THE BLUE RIDGE IN THE SOUTHERN COUNTY
WARNING AREA AFTER 16Z WITH SURFACE DEW POINTS DROPPING JUST BELOW
ZERO. WILL ALSO BE CUTTING BACK CHANCE OF SNOW IN THE NORTHWEST
NORTH CAROLINA MOUNTAINS AFTER 15Z THIS MORNING SINCE MOST OF THE
GUIDANCE HAS THE LOW LEVEL MOISTURE PULLING OUT BY THEN.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
TONIGHT...MODEL TRENDS CONTINUE TO SHOW DRIER AIR MOVING IN
QUICKLY...AND THE SHALLOW LAYER THROUGH ABOUT 4KFT WHERE ANY
REMAINING LOW LEVEL MSTR EXISTS WILL BE COOLING TO BELOW THE
PRIMARY ICE CRYSTAL GROWTH REGION. DESPITE SOME SHALLOW
INSTABILITY AND FAVORED TRAJECTORIES FOR OVERNIGHT BANDING...IT
APPEARS TO BE TOO DRY AND ACTUALLY TOO COLD TO GET ENOUGH ICE
CRYSTAL DEVELOPMENT TO BE TOO CONCERNED ABOUT LIGHT ACCUMULATIONS INTO
THE DOWNSLOPE AREAS. FAR WESTERN SLOPES...MAINLY WEST OF BLF
NORTHWARD INTO WRN GREENBRIER DUE TO THE OROGRAPHIC LIFT...WILL BE
THE ONLY LOCATIONS WORTH KEEPING A POP GOING...AND FOR THE TIME
BEING STILL HAVE A HALF INCH TO AN INCH OVERNIGHT IN THE MOST
FAVORED AREAS. DID KEEP MENTION OF FLURRIES EAST INTO THE
ALLEGHANY HIGHLANDS AND NEW RIVER VALLEY THROUGH MUCH OF THE
OVERNIGHT. OTHERWISE OVERNIGHT...WINDS CONTINUE TO SLACKEN A
BIT...BUT SECOND WAVE AND JET MAX ROUNDS BOTTOM OF TROF PROVIDING
ONE LAST LITTLE BURST OF WIND...MAINLY ALONG RIDGE TOPS...TOWARD
FRI MORNING. NOT NEARLY AS STRONG THOUGH AS WINDS THIS
MORNING...SO DOUBT ANY NEED FOR WIND ADV.
GOING CLOSE TO MAV GUIDANCE TONIGHT AND FRIDAY...WHICH HAS NOT
CHANGED MUCH LAST FEW RUNS...AND WITH EXPECTED BREEZY CONDITIONS
LASTING THROUGH FRIDAY...EXPECT WIND ADV CRITERIA WHICH IS 5
BELOW...WILL BE MET FROM THIS EVENING THROUGH EARLY FRIDAY
AFTERNOON IN MUCH OF THE WEST...AND FOR AT LEAST A FEW HOURS EVEN
IN THE ROANOKE AREA AND ALONG THE FOOTHILLS EARLY FRIDAY. SO HAVE
HOISTED A WIND CHILL ADV FOR MOST OF THE WEST FROM THIS EVENING
THROUGH 3PM FRI...AND FOR EARLY FRI MORNING FOR THE SECOND AREA
MENTIONED. WIND CHILLS AT THE HIGHEST PEAKS IN THE WEST MAY DROP
BRIEFLY BELOW 20 BELOW EARLY FRIDAY...BUT DOES NOT APPEAR TO BE
WIDESPREAD ENOUGH FOR WARNING. STILL VERY DANGEROUS CONDITIONS
FROM LATE TODAY THROUGH MUCH OF FRIDAY. ANY SNOW SHOWER ACTIVITY
WILL ALSO DISAPPEAR ALONG WRN SLOPES BY EARLY FRIDAY MORNING AS
ANY LINGERING MSTR DRIES UP.
SFC HIGH BUILDS IN FRIDAY NIGHT FOR GOOD RADIATIONAL COOLING MOST
PLACES. SLOWER NAM KEEPS SFC HIGH CENTERED OVER THE WEST BY EARLY
SAT MORNING..BUT FASTER GFS AND ENSEMBLES IS PREFERRED AND SO BLV
SFC HIGH WILL E OVER THE PIEDMONT BY 12Z...ALLOWING FOR SOME WEAK
WARM ADV TO BEGIN IN THE WEST TOWARD MORNING. THIS WILL HAVE
EFFECT OF NOT ALLOWING LOWS TO BOTTOM OUT AS MUCH AS THEY
COULD...BUT STILL THINK GUIDANCE COULD BE TOO WARM...ESPECIALLY
WHERE THERE IS ANY SNOW COVER. WENT CLOSER TO COLDER MAV FOR SAT
MORNING LOWS....BUT MAY HAVE TO TREND UPWARD A BIT IF TRENDS
CONTINUE TO BE FASTER WITH BEGINNING OF WARM ADV AND MAYBE SOME
CLOUD COVER.
NEXT WAVE STILL FCST TO DIG TO THE WEST OF THE REGION BY
SUNDAY...AND GFS WHICH IS SLOWER THAN ECMWF IS PREFERRED BASED ON
ENSEMBLE MEANS. TE TREND HAS BEEN TO DIG THIS A LITTLE DEEPER AND
THUS A SLOWER TRENDS IS PROBABLY RIGHT IDEA. THIS WOULD KEEP ANY
PRECIP TO OUR NORTH AND WEST THROUGH SAT NIGHT...WITH AN INITIAL
WAVE LIFTING TO THE NORTH AS THE MAIN WAVE DIGS SOUTHWARD THROUGH
THE MIDWEST. HAVE HELD OFF PRECIP UNTIL SUNDAY THEN...BUT ALSO
INCREASED POPS IN THE EAST LATE SUNDAY AS LOW LEVEL WINDS BACK AND
MODELS SHOW FAIRLY DEEP AREA OF SYNOPTIC SCALE FORCING COMING
ACROSS THE BLUE RIDGE. STILL CHC POPS FOR NOW...BUT THIS PATTERN
IS LOOKING FAVORABLE FOR PERHAPS SOME VERY LIGHT SNOW
ACCUMULATIONS EAST OF THE TRADITIONAL UPSLOPE AREAS...MAYBE EVEN
OUT INTO THE PIEDMONT. TEMPS BEGINNING TO MODERATE THOUGH...BUT
WET BULBS STILL QUITE LOW...SO IF PRECIP IS NOT TOO LIGHT SHOULD
BE ALL SNOW. WENT CLOSER TO COOLER MET GUIDANCE HIGHS EXPECTING
ANY PRECIP AND WET BULBING WILL HOLD TEMPS DOWN. STILL PRETTY
EARLY TO SAY MUCH MORE ABOUT THIS SYSTEM...BUT WORTH KEEPING AN
EYE ON FOR POSSIBLE LIGHT SNOW FOR MOST LOCATIONS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
RENEWED COLD ADVECTION SUNDAY NIGHT ON THE BACK SIDE OF THE
CLIPPER LOOKS COLD...BUT NOWHERE NEAR THE ARCTIC AIR FROM EARLIER
IN THE WEEKEND WITH THE SOURCE REGION EASTERN CANADA. WILL HAVE
MAINLY UPSLOPE SNOW SHOWERS IN THE MTNS SUNDAY NIGHT.
YET ANOTHER CLIPPER-LIKE SHORT WAVE MAY AFFECT THE AREA MONDAY...BUT
LOOKS TO TRACK A LITTLE FURTHER NORTH. HAVE STAYED CLOSE TO HPC
GUIDANCE FOR THIS ONE...WITH LOW POPS CONFINED TO THE MTNS...HIGHEST
IN SE WV. ONCE AGAIN...MORE COLD ADVECTION MONDAY NIGHT BEHIND THIS
CLIPPER...WITH UPSLOPE SNOW SHOWERS IN THE MTNS.
FINALLY...ANOTHER SHORT WAVE SLIDING DOWN THE TROUGH TUESDAY OR
TUESDAY NIGHT MAY BRING MORE SNOW SHOWERS TO THE MTNS. HAVE STAYED
WITH HPC GUIDANCE WHICH FOLLOWS THE SLOWER ECMWF. THIS BRING A COLD
FRONT THROUGH LATE WEDNESDAY...AND ALLOWS HIGH TEMPS TO WARM QUITE
BIT AHEAD OF THE FNT ON WED.
&&
.AVIATION /12Z THURSDAY THROUGH MONDAY/...
CHECK AIRMETS AND SIGMETS FOR TURBULENCE...ICING AND MOUNTAIN
OBSCURATIONS TONIGHT INTO THURSDAY. MVFR CEILINGS WERE ALONG AND
WEST OF THE COLD FRONT WERE SPREADING ACROSS THE MOUNTAINS. NW
WINDS WILL LEAD TO NUMEROUS SNOW SHOWERS WITH MVFR VISIBILITIES.
ELSW...MAINLY VFR IN AC...WITH A BKN LAYER OF MVFR/VFR STRATO-CU
POSSIBLE AT KROA UNTIL 00Z.
DRIER AIR AND VFR CONDITIONS WILL COME IN TONIGHT AND FRIDAY
ALONG WITH A LARGE HIGH AND ARCTIC AIR. ANOTHER FRONTAL BOUNDARY
ARRIVES SATURDAY NIGHT INTO SUNDAY WITH A CHANCE OF MVFR SNOW
SHOWERS FOR THE ENTIRE COUNTY WARNING AREA.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 3 PM EST FRIDAY
FOR VAZ007-009>020.
WIND CHILL ADVISORY FROM 6 AM TO 12 PM EST FRIDAY FOR
VAZ022>024-032>035.
WIND ADVISORY UNTIL NOON EST TODAY FOR VAZ015.
NC...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 3 PM EST FRIDAY
FOR NCZ001-002-018.
WIND CHILL ADVISORY FROM 6 AM TO 12 PM EST FRIDAY FOR NCZ003-
019.
WIND ADVISORY UNTIL NOON EST TODAY FOR NCZ001-002-018.
WV...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 3 PM EST FRIDAY
FOR WVZ042>045.
WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
WVZ045.
&&
$$
SYNOPSIS...SK
NEAR TERM...AMS
SHORT TERM...SK
LONG TERM...JJ
AVIATION...AMS/JH
000
FXUS61 KRNK 150949
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
449 AM EST THU JAN 15 2009
.SYNOPSIS...
ARCTIC AIR BEHIND A COLD FRONT WILL CONTINUE TO INFILTRATE THE
REGION DURING THE DAY...BRINGING WITH IT THE COLDEST AIR OF THE
SEASON THROUGH THE END OF THE WEEK. GUSTY WINDS WILL RESULT IN
DANGEROUS WIND CHILLS AT TIMES THROUGH FRIDAY...AND SOME SNOW
ACCUMULATION WITH BLOWING SNOW IS EXPECTED ALONG WESTERN MOUNTAIN
SLOPES THROUGH TONIGHT.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AFTER THE 15-18Z TIME FRAME THE 850 MB WINDS DROP BELOW 35 KNOTS AND
PRESSURE RISES ARE NOT AS LARGE DURING THE AFTERNOON. WILL CONTINUE
THE WIND ADVISORY IN GRAYSON COUNTY AND THE NORTHWEST NORTH CAROLINA
MOUNTAINS THROUGH NOON TODAY.
AT 09Z THE ARCTIC COLD FRONT WAS JUST PASSING THROUGH ROANOKE AND
MOVING EAST ACROSS THE BLUE RIDGE. THE FRONT WILL BE WELL THROUGH
THE ENTIRE COUNTY WARNING AREA BY 12Z. SURFACE TEMPERATURES WILL
BE STEADY OR WILL SLOWLY FALL TODAY AS 850 MB TEMPERATURES DROP
INTO THE -15 TO -20 RANGE BY 00Z. HOURLY TEMPERATURES WILL REFLECT
AN ATYPICAL DIURNAL TREND TODAY.
AT TIME MOMENT LOW LEVEL MOISTURE IS DEEP ENOUGH ALL THE WAY SOUTH
INTO NORTH CAROLINA FOR SNOW SHOWERS TO CONTINUE THROUGH THE
MORNING. BUT THE LOCAL WRF IS SHOWING SOME DECENT SUBSIDENCE AND
DRYING ALONG THE LEE SIDE OF THE BLUE RIDGE IN THE SOUTHERN COUNTY
WARNING AREA AFTER 16Z WITH SURFACE DEW POINTS DROPPING JUST BELOW
ZERO. WILL ALSO BE CUTTING BACK CHANCE OF SNOW IN THE NORTHWEST
NORTH CAROLINA MOUNTAINS AFTER 15Z THIS MORNING SINCE MOST OF THE
GUIDANCE HAS THE LOW LEVEL MOISTURE PULLING OUT BY THEN.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY/...
TONIGHT...MODEL TRENDS CONTINUE TO SHOW DRIER AIR MOVING IN
QUICKLY...AND THE SHALLOW LAYER THROUGH ABOUT 4KFT WHERE ANY
REMAINING LOW LEVEL MSTR EXISTS WILL BE COOLING TO BELOW THE
PRIMARY ICE CRYSTAL GROWTH REGION. DESPITE SOME SHALLOW
INSTABILITY AND FAVORED TRAJECTORIES FOR OVERNIGHT BANDING...IT
APPEARS TO BE TOO DRY AND ACTUALLY TOO COLD TO GET ENOUGH ICE
CRYSTAL DEVELOPMENT TO BE TOO CONCERNED ABOUT LIGHT ACCUMULATIONS INTO
THE DOWNSLOPE AREAS. FAR WESTERN SLOPES...MAINLY WEST OF BLF
NORTHWARD INTO WRN GREENBRIER DUE TO THE OROGRAPHIC LIFT...WILL BE
THE ONLY LOCATIONS WORTH KEEPING A POP GOING...AND FOR THE TIME
BEING STILL HAVE A HALF INCH TO AN INCH OVERNIGHT IN THE MOST
FAVORED AREAS. DID KEEP MENTION OF FLURRIES EAST INTO THE
ALLEGHANY HIGHLANDS AND NEW RIVER VALLEY THROUGH MUCH OF THE
OVERNIGHT. OTHERWISE OVERNIGHT...WINDS CONTINUE TO SLACKEN A
BIT...BUT SECOND WAVE AND JET MAX ROUNDS BOTTOM OF TROF PROVIDING
ONE LAST LITTLE BURST OF WIND...MAINLY ALONG RIDGE TOPS...TOWARD
FRI MORNING. NOT NEARLY AS STRONG THOUGH AS WINDS THIS
MORNING...SO DOUBT ANY NEED FOR WIND ADV.
GOING CLOSE TO MAV GUIDANCE TONIGHT AND FRIDAY...WHICH HAS NOT
CHANGED MUCH LAST FEW RUNS...AND WITH EXPECTED BREEZY CONDITIONS
LASTING THROUGH FRIDAY...EXPECT WIND ADV CRITERIA WHICH IS 5
BELOW...WILL BE MET FROM THIS EVENING THROUGH EARLY FRIDAY
AFTERNOON IN MUCH OF THE WEST...AND FOR AT LEAST A FEW HOURS EVEN
IN THE ROANOKE AREA AND ALONG THE FOOTHILLS EARLY FRIDAY. SO HAVE
HOISTED A WIND CHILL ADV FOR MOST OF THE WEST FROM THIS EVENING
THROUGH 3PM FRI...AND FOR EARLY FRI MORNING FOR THE SECOND AREA
MENTIONED. WIND CHILLS AT THE HIGHEST PEAKS IN THE WEST MAY DROP
BRIOEFLY BELOW 20 BELOW EARLY FRIDAY...BUT DOES NOT APPEAR TO BE
WIDESPREAD ENOUGH FOR WARNING. STILL VERY DANGEROUS CONDITIONS
FROM LATE TODAY THROUGH MUCH OF FRIDAY. ANY SNOW SHOWER ACTIVITY
WILL ALSO DISSAPPEAR ALONG WRN SLOPES BY EARLY FRIDAY MORNING AS
ANY LINGERING MSTR DRIES UP.
SFC HIGH BUILDS IN FRIDAY NIGHT FOR GOOD RADIATIONAL COOLING MOST
PLACES. SLOWER NAM KEEPS SFC HIGH CENTERED OVER THE WEST BY EARLY
SAT MORNING..BUT FASTER GFS AND ENSEMBLES IS PREFERED AND SO BLV
SFC HIGH WILL E OVER THE PIEDMONT BY 12Z...ALLOWING FOR SOME WEAK
WARM ADV TO BEGIN IN THE WEST TOWARD MORNING. THIS WILL HAVE
EFFECT OF NOT ALLOWING LOWS TO BOTTOM OUT AS MUCH AS THEY
COULD...BUT STILL THINK GUIDANCE COULD BE TOO WARM...ESPECIALLY
WHERE THERE IS ANY SNOW COVER. WENT CLOSER TO COLDER MAV FOR SAT
MORNING LOWS....BUT MAY HAVE TO TREND UPWARD A BIT IF TRENDS
CONTINUE TO BE FASTER WITH BEGINING OF WARM ADV AND MAYBE SOME
CLOUD COVER.
NEXT WAVE STILL FCST TO DIG TO THE WEST OF THE REGION BY
SUNDAY...AND GFS WHICH IS SLOWER THAN ECMWF IS PREFERRED BASED ON
ENSEMBLE MEANS. TE TREND HAS BEEN TO DIG THIS A LITTLE DEEPER AND
THUS A SLOWER TRENDS IS PROBABLY RIGHT IDEA. THIS WOULD KEEP ANY
PRECIP TO OUR NORTH AND WEST THROUGH SAT NIGHT...WITH AN INITIAL
WAVE LIFTING TO THE NORTH AS THE MAIN WAVE DIGS SOUTHWARD THROUGH
THE MIDWEST. HAVE HELD OFF PRECIP UNTIL SUNDAY THEN...BUT ALSO
INCREASED POPS IN THE EAST LATE SUNDAY AS LOW LEVEL WINDS BACK AND
MODELS SHOW FAIRLY DEEP AREA OF SYNOPTIC SCALE FORCING COMING
ACROSS THE BLUE RIDGE. STILL CHC POPS FOR NOW...BUT THIS PATTERN
IS LOOKING FAVORABLE FOR PERHAPS SOME VERY LIGHT SNOW
ACCUMULATIONS EAST OF THE TRADITIONAL UPSLOPE AREAS...MAYBE EVEN
OUT INTO THE PIEDMONT. TEMPS BEGINNING TO MODERATE THOUGH...BUT
WET BULBS STILL QUITE LOW...SO IF PRECIP IS NOT TOO LIGHT SHOULD
BE ALL SNOW. WENT CLOSER TO COOLER MET GUIDANCE HIGHS EXPECTING
ANY PRECIP AND WET BULBING WILL HOLD TEMPS DOWN. STILL PRETTY
EARLY TO SAY MUCH MORE ABOUT THIS SYSTEM...BUT WORTH KEEPING AN
EYE ON FOR POSSIBLE LIGHT SNOW FOR MOST LOCATIONS.
&&
.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
RENEWED COLD ADVECTION SUNDAY NIGHT ON THE BACK SIDE OF THE
CLIPPER LOOKS COLD...BUT NOWHERE NEAR THE ARCTIC AIR FROM EARLIER
IN THE WEEKEND WITH THE SOURCE REGION EASTERN CANADA. WILL HAVE
MAINLY UPSLOPE SNOW SHOWERS IN THE MTNS SUNDAY NIGHT.
YET ANOTHER CLIPPER-LIKE SHORT WAVE MAY AFFECT THE AREA MONDAY...BUT
LOOKS TO TRACK A LITTLE FURTHER NORTH. HAVE STAYED CLOSE TO HPC
GUIDANCE FOR THIS ONE...WITH LOW POPS CONFINED TO THE MTNS...HIGHEST
IN SE WV. ONCE AGAIN...MORE COLD ADVECTION MONDAY NIGHT BEHIND THIS
CLIPPER...WITH UPSLOPE SNOW SHOWERS IN THE MTNS.
FINALLY...ANOTHER SHORT WAVE SLIDING DOWN THE TROUGH TUESDAY OR
TUESDAY NIGHT MAY BRING MORE SNOW SHOWERS TO THE MTNS. HAVE STAYED
WITH HPC GUIDANCE WHICH FOLLOWS THE SLOWER ECMWF. THIS BRING A COLD
FRONT THROUGH LATE WEDNESDAY...AND ALLOWS HIGH TEMPS TO WARM QUITE
BIT AHEAD OF THE FNT ON WED.
&&
.AVIATION /09Z THURSDAY THROUGH MONDAY/...
CHECK AIRMETS AND SIGMETS FOR TURBULENCE...ICING AND MOUNTAIN
OBSCURATIONS TONIGHT INTO THURSDAY. LOWERING CEILINGS SLOWLY
SPREADING EAST TOWARD THE WESTERN SITES AHEAD OF THE COLD FRONT IN
EASTERN KY ATTM. THIS FRONT WILL CROSS THE REGION AFTER MIDNIGHT WITH
NW WINDS INCREASING AS WELL AS SNOW SHOWERS ALONG THE WESTERN
SLOPES. STILL EXPECTING MVFR CEILINGS WITH MVFR/IFR SNOW SHOWERS
TO DEVELOP 06-08Z BEHIND THE COLD FRONT IN THE MOUNTAINS.
ELSW...MAINLY VFR IN AC...WITH A BKN LAYER OF MVFR/VFR STRATO-CU
POSSIBLE AT KROA BEFORE 12Z. WINDS WILL ALSO INCREASE FROM THE
WEST TO NORTHWEST WITH GUSTS FROM 07-15Z AROUND 40 KNOTS AT HIGHER
ELEVATIONS.
DRIER AIR AND VFR CONDITIONS WILL COME IN ON THURSDAY NIGHT AND
FRIDAY ALONG WITH A LARGE HIGH AND ARCTIC AIR. ANOTHER FRONTAL
BOUNDARY ARRIVES SATURDAY NIGHT INTO SUNDAY WITH ADDITIONAL
WESTERN SLOPE SNOW SHOWERS MAKING FOR POSSIBLE INCLUDING MVFR
CONDITIONS. DRIER AIR SHOULD FOLLOW THE FRONT PRODUCING A VFR
OUTLOOK IN MOST AREAS FOR EARLY NEXT WEEK.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 3 PM EST FRIDAY
FOR VAZ007-009>020.
WIND CHILL ADVISORY FROM 6 AM TO 12 PM EST FRIDAY FOR
VAZ022>024-032>035.
WIND ADVISORY UNTIL NOON EST TODAY FOR VAZ015.
NC...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 3 PM EST FRIDAY
FOR NCZ001-002-018.
WIND CHILL ADVISORY FROM 6 AM TO 12 PM EST FRIDAY FOR NCZ003-
019.
WIND ADVISORY UNTIL NOON EST TODAY FOR NCZ001-002-018.
WV...WIND CHILL ADVISORY FROM 9 PM THIS EVENING TO 3 PM EST FRIDAY
FOR WVZ042>045.
WINTER WEATHER ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
WVZ045.
&&
$$
SYNOPSIS...SK
NEAR TERM...AMS
SHORT TERM...SK
LONG TERM...JJ
AVIATION...AMS
[top]
000
FXUS61 KLWX 150837
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
337 AM EST THU JAN 15 2009
.SYNOPSIS...
LOW PRESSURE AND ITS ASSOCIATED COLD FRONT WILL MOVE OFF THE COAST
THIS MORNING. VERY COLD TEMPERATURES ARE EXPECTED BEHIND THIS SYSTEM
THROUGH THE FIRST PART OF THE WEEKEND. UPPER LEVEL LOW PRESURE
WILL CONTINUE TO INFLUENCE THE WEATHER OF THE MID ATLANTIC REGION
SUNDAY THROUGH TUESDAY. HIGH PRESSURE WILL MOVE INTO THE REGION
FOR THE SECOND HALF OF THE WEEK.
&&
.NEAR TERM /TODAY/...
AS W/ YDA`S DSCN I`M INCLUDING THE CLIMATE SXN BLO WRITTEN BY THE
DAYSHIFT TEAM. BUT I CONT TO DO SOME RESEARCH ON COLD WX AT THE
MAJOR THREE AIRPORTS. MORE "INTERESTING TO NOTES" - IN PAST 10 YRS
DCA HAS ONLY BEEN SUB TEN DEGS ONCE - REACHING +8 ON 1/10/04. BWI
HAS DONE IT 17 TIMES...IAD 24...W/ THE LOWEST OF +1 ON 12/7/02.
BUT NONE HV BEEN SUB ZERO IN PAST TEN YRS. AT DCA NO JAN RECORD
MIN HAS BEEN SET SINCE 1994. SO IN SPITE OF THE APRCHG COLD AIR -
THE STRONGEST I`VE SEEN IN A LONG TIME HERE...COLD DOESN`T SEEM TO
BE AS COLD AS IT USED TO.
BUT IT STILL WL BE COLD FOR THE NEXT SVRL DAYS AS THE WORLD TURNS
IT`S EYES TO ONE OF THE MOST IMPORTANT STRETCHES OF DAYS IN DC
HISTORY. 04Z SFC ANLYS SHOWS A RLTVLY WEAK LOW PRES AREA CENTERED
OVR THE NRN PART OF THE CWA WHICH IS RESPONSIBLE FOR THE SNOWS
BEING RCVD IN THE WRN PART OF THE CWA. RCVD A CALL FM A FROSTBURG
SPOTTER ARND 1 AM REPORTING 2.5" HAS FALLEN SINCE THIS AFTN OF
XTRMLY POWDERY SNOW. HV SEEN LIQUID/SNOW RATIOS OF 20-1 DISCUSSED
IN THE WX CHAT ROOM...WHICH SEEMS REASONABLE. THIS WL CONT THRU
THE MRNG HRS..ANOTHER INCH OR TWO PSBL IN THE WRN HIGHLANDS SO
WINT WX ADVSRY RMNS INTACT.
ANLYS ALSO SHOWED THE STRONGEST HIGH PRES I`VE SEEN IN AWHILE -
ALMOST 1046 MB OVR NRN ND. CURRENTLY -31 AT DEVILS LAKE. BRRRR.
WIND CHILL ADVSRY - THE 0730Z WIND CHILL PLOT SHOWS NO VALUES L.T.
+10. WE HV IT GOING INTO EFFECT AT 09Z...WHICH DOESN`T SEEM LKLY
TO ME. I`M GOING TO PUSH THE START BACK TO 12Z...AND HONESTLY I
SEE THIS AS MARGINAL AT BEST. BUT SOME -5 WIND CHILLS COULD BE
REACHED TDA.
RMDR OF CWA TDA...RDR SHOWS S- ACROSS THE NRN AND WRN PARTS OF THE
CWA. HRR RUC SHOW THIS CONTINUING THRU THE MRNG HRS THEN TAPERING
OFF. HIGH PRES WL SPEND THE DAY BUILDING INTO THE RGN WHICH WL
MAKE IT BRZY ALTHO NOT NEAR ADVSRY LVLS.
TEMPS WL NOT DO MUCH IF ANY CLIMBING TDA. HIGHS RANGING FM TEENS
FAR W TO LM30S ALONG THE BAY.
&&
.SHORT TERM /TONIGHT/...
HIGH PRES CONTS TO BUILD IN TNGT. NW WINDS ARND 10 KT AFTR 00Z.
TEMPS COULD GO SUB ZERO IN THE HIGHLANDS...M TEENS IN LOWER SRN MD.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
IN TERMS OF AMBIENT TEMP...THU NIGHT WILL LIKELY BE THE COLDEST
OF THE YEAR. THE ARCTIC INTRUSION OF THE MID ATLC WILL BE AT IT/S
MAXIMUM EFFECT DURING THE PRE-DAWN HRS FRI MORNING. THE ERN EDGE
OF A +1045MB SFC HIGH WILL BE BUILDING ACROSS THE MID ATLC.
FORTUNATELY...EVEN W/ TEMPS DROPPING INTO THE SINGLE DIGITS AND
INTO SUBZERO READINGS OVERNIGHT...WINDS ARE EXPECTED TO DROP OFF
VERY LIGHT/VRB. WINDS STILL MAY BE A FACTOR FOR THE EVNG AND LATE
NIGHT HRS THO...SO WIND CHILL PRODUCTS MAY BE WARRANTED FOR THE HRS
PRECLUDING WINDS DROPPING OFF OVERNIGHT. HOLDING OFF A WIND CHILL
WATCH FOR THE WRNMOST ZONES. THE MOST LIKELY SCENARIO BEING A WIND
CHILL ADVISORY WEST OF THE VA BLUE RIDGE...INCLUDING THE SHENANDOAH
VLY AND SURROUNDING AREAS OF THE CNTRL APLCNS.
THE SFC HIGH CONTINUES TO MOVE TOWARD THE MID ATLC DURING THE DAY
FRIDAY...WEAKENING AS ANOTHER QUICK VORT LOBE SPEEDS TOWARD THE
REGION FROM THE UPPER MIDWEST. THE ELONGATED HIGH OVER THE LENGTH
OF THE EAST COAST THEN GETS SPLIT BY THE INCOMING LOW. AS THE LOW
SLIDES THRU THE GRT LKS REGION...IT STALLS OVER WRN NY AS A BACKSIDE
UPPER TROF DEEPENS INTO THE MID MISSISSIPPI VLY. HOW DEEP AND THE
PROXIMITY OF THIS TROF AXIS WILL BE KEY IN DETERMINING WHETHER ANY
OF THE ASSOCIATED MOISTURE EITHER GETS DRAWN UP INTO THE MID ATLC
FROM THE GULF COAST REGION...AND/OR GETS PUSHED PAST THE CNTRL
APLCNS SUNDAY INTO THE OVERNIGHT HRS. GFS PAINTING A SOLUTION
SIMILAR TO THE EVENTS OF EARLIER THIS WEEK...W/ AN AREA OF BROAD
LAKE EFFECT/UPSLOPE SNOWS ACROSS THE OHIO VLY...DISSIPATING OVER
THE MTNS.
A WEAK AND THINLY STRETCHED BAND OF LOW LEVEL GULF MOISTURE THEN
GETS FORCED UP THE ERN SEABOARD LATE SUNDAY AND ALL THIS ACTIVITY
SLIDES OFF THE ATLC COAST BY EARLY MONDAY. FOR NOW...A BROAD LOW
CHANCE POP AREA WILL SUFFICE W/ THE UNCERTAINTY IN STRENGTH/TIMING
OF ANY ONE OF THESE ELEMENTS LINING UP DURING THE LATER PART OF
THE WEEKEND.
ACROSS THE WRN HALF OF THE COUNTRY...A HIGH PRESSURE RIDGE BUILDS
DUE NORTH ALL THE WAY INTO THE NW TERRITORIES. THE EFFECT ON THE
ERN HALF OF THE COUNTRY IS AN UPPER TROF THAT PUSHES DOWN OVER THE
GULF OF MEXICO. AT LEAST A COUPLE MORE UPPER VORT LOBES WILL SLIDE
DOWN THE BACKSIDE OF THE UPPER TROF INTO THE MID ATLC THRU MID WEEK.
NEITHER OF THE UPPER WAVES EXPECTED DO MUCH MORE THAN REINFORCE THE
SUBFREEZING TEMPS AND POSSIBLY SLIDE ACROSS AREAS OF SCATTERED
FLURRIES W/ EACH PASSAGE. THE WRN RIDGE THEN BEGINS TO BUILD INTO
THE CNTRL AND ERN STATES TOWARD THE END OF NEXT WEEK.
&&
.AVIATION /TODAY THROUGH MONDAY/...
VFR CONDS...ISOLD SNSH PSBL AT MAJOR AIRPORTS THIS MRNG W/ SOME
DEGRADATION TO CIGS/VSBY. VFR CONDS TNGT.
BREEZY WLY WINDS ON FRIDAY. HIGH PRESSURE FOR FRI/SAT. A QUICK
MOVING UPPER LOW WILL APPROACH THE REGION ON SUNDAY...W/ SOME
SCATTERED SNOW SHOWERS POSSIBLE BUT VERY LIGHT ACTIVITY EXPECTED.
LITTLE MORE THAN BREEZY CONDITIONS EXPECTED EARLY NEXT WEEK AND
POSSIBLE FLURRIES AT TIMES THRU MID WEEK.
&&
.MARINE...
SCA IN EFFECT AS COLDER/DENSE AIR POURS INTO MID ATLC FOR TDA AND
TNGT. DOUBTFUL TOO MANY PLEASURE MARINERS ARE OUT THERE - TPLM
WATER TEMP IS 37.
MARGINAL SCA CONDITIONS ON FRIDAY AFTN/EVNG. WINDS EXPECTED TO
STAY FAIRLY LIGHT ACROSS THE WATERS THRU THE WEEKEND INTO THE
MON AFTN...FROM ANOTHER UPPER LEVEL SYSTEM. HIGH PRES WILL THEN
GRADUALLY BUILD INTO THE REGION STARTING MID WEEK.
&&
.CLIMATE...
VERY COLD WEATHER IS STILL EXPECTED THIS FRIDAY /16 JAN/ INTO
SATURDAY MORNING /17 JAN/. HOWEVER...SINCE THIS IS NEAR THE
CLIMATOLOGICALLY COLDEST TIME OF YEAR...RECORD LOWS AND/OR RECORD
LOW MAXIMUM TEMPERATURES ARE UNLIKELY IN THE BALTIMORE/WASHINGTON
METROPOLITAN AREA. DESPITE GUIDANCE SUGGESTING SLIGHTLY HIGHER
TEMPERATURES ON SATURDAY MORNING...IT STILL DOES LOOK TO BE SOME OF
THE COLDEST AIR IN THE PAST 15 YEARS. PLEASE NOTE THAT IT WAS
SIGNIFICANTLY COLDER DURING A COLD SPELL IN MID JANUARY 1994 AT
BWI/DCA/IAD.
BELOW ARE THE LATEST FORECAST MAXIMA FOR FRIDAY AND MINIMA FOR
SATURDAY AT BWI/DCA/IAD WITH RECENT TIMES TEMPERATURES NEARED THESE
VALUES...AS WELL AS RECORD LOWEST MAX ON 16 JAN AND RECORD LOW ON 17
JAN.
BWI...FRI FCST HIGH: 20 F /HIGH OF 19 F ON JAN 10 2004 AND FEB 4
1996 AND 20 ON FEB 5 2007...RECORD LOW MAXIMUM OF 14 F IN 1893/
DCA...FRI FCST HIGH: 20 F /HIGH OF 17 F ON FEB 4 1996 AND 20 F ON
FEB 3 1996 AND 21 F ON JAN 10 2004...RECORD LOW MAXIMUM OF 15 F IN
1893/
IAD...FRI FCST HIGH: 19 F /HIGH OF 14 F ON FEB 4 1996 AND 19 F ON
JAN 17-18 1997 AND 20 ON FEB 5 2007...RECORD LOW MAXIMUM OF 14 IN
1972 AND 1996/
BWI...SAT FCST LOW: 5 F /LOW OF 1 ON JAN 19 1997 AND 4 ON FEB 6 1996
AND 5 ON JAN 18 2003...RECORD LOW OF -7 IN 1982/
DCA...SAT FCST LOW: 9 F /LOW OF 8 F ON JAN 10 2004 AND 9 ON FEB 4
1996...RECORD LOW OF -5 IN 1982/
IAD...SAT FCST LOW: 3 F /LOW OF 1 F ON DEC 7 2002 AND 3 ON JAN 29
2004...RECORD LOW OF -7 IN 1982/
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR MDZ501-502.
WIND CHILL ADVISORY UNTIL 6 PM EST THIS AFTERNOON FOR MDZ501-
502.
VA...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR VAZ021.
WIND CHILL ADVISORY UNTIL 6 PM EST THIS AFTERNOON FOR VAZ021.
WV...WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR WVZ054-
501>504.
WIND CHILL ADVISORY UNTIL 6 PM EST THIS AFTERNOON FOR WVZ054-
501>504.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR ANZ530>537.
&&
$$
PRODUCTS...WOODY!/GMS
CLIMATE...BPP/BJL
[top]
000
FXUS61 KAKQ 150821
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
321 AM EST THU JAN 15 2009
.SYNOPSIS...
LOW PRESSURE MOVES EAST OFF THE NEW JERSEY COAST THIS MORNING.
THE LOW WILL DRAG A STRONG COLD FRONT THROUGH THE MID ATLANTIC
REGION THIS MORNING...AND WILL BE FOLLOWED BY ARCTIC HIGH
PRESSURE AND VERY COLD AIR FOR THURSDAY NIGHT INTO SATURDAY. A
CLIPPER SYSTEM WILL APPROACH FROM THE NORTHWEST SATURDAY
NIGHT...THEN TRACK ACROSS THE MID ATLANTIC REGION LATE SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
SFC LO PRES LCTD OVR NRN VA ATTM...W/ TRAILING ARCTIC CDFNT ALIGNED
SWWD INVOF I81 CORRIDOR. MOD SFC PRES RISES IN WAKE OF FNT...CNTRD
OVR SE OH/WRN WV. SWLY FLO PRE-FNT OVR FA THROUGH THE ERY/MID MRNG
HRS...RESULTING TEMPS CLIMBING (INTO) THROUGH 30S. FNTL PASSAGE
THROUGH FA BY LT THIS MRNG...AND W/ IT...WNDS SHIFT TO WNW AND BCM
GSTY. STRNG LLVL CAA XPCTD FM MID/LT MRNG THROUGH THE AFTN
HRS...AS COLDEST AMS OF THE WINTER THUS FAR ARRIVES IN ERNEST. HI
TEMPS IN THE M/U30 TO L40S THIS MRNG...B4 FALLING THIS AFTN
DESPITE CLRG.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
BRR...DEEP TROUGH ALOFT SWINGS THROUGH THE FA LT FRI/FRI NGT. CNTR
OF STRNG SFC HI PRES SLO TO BUILD EWD FM THE MIDWEST THROUGH FRI
EVE...W/ CNTR ARRIVING OVR FA FOR LT FRI NGT AND SAT. WNDSPDS SLO
TO DCRS TNGT...COMBINED W/ TEMPS DROPPING INTO THE TEENS/L20S IN
MANY PLCS...RESULTS IN WND CHILLS IN SINGLE DIGITS/LWR TEENS. AMS
WL BE XTRMLY DRY W/ DWPTS DIPPING TO AOB ZERO MOST PLCS. LLVL
MIXING AND LACK OF SNWCVR KP TEMPS FM DROPPING TO THOSE VALUES TNGT.
DESPITE AMPLE SUNSHINE ON FRI...RDGS STRUGGLE TO REACH THE M/U20S
ACRS FA (SEE CLIMO SXN BLO TO SEE WHEN IT WAS THIS COLD ARND THESE
PARTS). EVEN THOUGH AMS QUITE DRY...STILL SOME CONCERN ABT SNSHRAS
OVR THE WTRS...THOUGH LLVL TRAJ MR NW THAN N (LESS THAN IDEAL FOR
ANY PCPN INVOF ORF/NTU). HV KPT SLGT CHC OVR THE WTRS.
VRY COLD FRI NGT AS BLYR DCPLS...UNDER SKC AND W/ DWPTS AOB
ZERO...XPCTG WDSPRD SINGLE DIGITS (AWAY FM THE LRGR CITIES/BAY-
OCN) - NO SNWCVR ONCE AGN KPS TEMPS FM FALLING TO/BLO ZERO. NOT
XPCTG ANY QUIK WRMUP ON SAT AS LLVL WAA SLO TO MATERIALIZE.
EVENTUALLY...WNDS SHIFT TO MR SLY DRCTN...THAT IS NOT LIKELY B4 LT
AFTN. HI TEMPS SAT ONLY FM THE M20S TO L30S.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH PRES QUICKLY MOVES OFFSHORE AND AWAY FROM THE COAST SAT NIGHT
AS A COLD FRONT APPROACHES FROM THE NW. THE FRONT WILL CROSS THE
MID-ATLANTIC REGION SAT NIGHT THRU SUN NIGHT. THE GFS SOLUTION IS
NOW VERY SIMILAR TO THE ECMWF...WITH BOTH MODELS SHOWING SOME
AVAILABLE MOISTURE OVER OUR AREA. MEANWHILE THE GFS ALSO DEVELOPS A
WEAK COASTAL LOW OFF THE S CAROLINA COAST...THEN MOVES IT TO THE NE
AND AWAY FROM CAPE HATTERAS BY SUN NIGHT. WILL KEEP POPS TOPPED OUT
AT 30% AS THIS FEATURE MOVES THRU WITH THE HIGHEST CHANCE OF PRECIP
AND MOISTURE EXPECTED TO BE TO OUR S OVER SERN/ERN NC NEAR THE TRACK
OF THE LOW. TEMPS WILL BE COLD ENOUGH TO SUPPORT ALL SNOW OVER ALL
OF THE FA SAT NIGHT INTO EARLY SUN (LOWS NEAR 20 NW TO NEAR 30 SE).
WITH TEMPS EXPECTED TO RISE INTO THE LWR TO MID 40S DURING THE DAY
SUN EXPECT A TRANSITION TO A RAIN/SNOW MIX LATE MORNING THRU EARLY
AFTERNOON...THEN EVENTUALLY ALL RAIN BY THE LATE AFTERNOON. IT
SHOULD BE NOTED THAT ATTM IT APPEARS THAT ANY PRECIP THAT DOES
MANAGE TO GET SQUEEZED OUT OF THE ATMS IS EXPECTED TO BE LIGHT.
THE FRONT MOVES OFF THE COAST SUN NIGHT...SWEEPING THE LOW FARTHER
OUT TO SEA. KPG PCPN CHCS AT 30% ACRS FA SAT NGT AS MID/UPR LVL
TROUGH SHARPENS INVOF FA (PER LATEST GFS). SUN NIGHT LOW TEMPS
WILL AGAIN BE NEAR 20 NW TO LWR 30S FAR SE...SO ANY REMAINING
PRECIP IS EXPECTED TO BE LIGHT SNOW AS THE LOW DEPARTS.
TROFINESS PERSISTS OVER THE ERN SEABOARD ON MON AND UNDER NW
FLOW/FETCH COULD HAVE SOME (BAY EFFECT) SNOW SHOWERS DEVELOP OVER
THE LWR MD/VA ERN SHORE. HIGH TEMPS MON WILL BE NEAR 40 TO NEAR
45. HIGH PRES RIDGES IN FROM THE SW/W MON NIGHT INTO NEXT WED.
LOWS MON NIGHT WILL BE IN THE UPR TEENS FAR NW TO NEAR 30 FAR SE.
NW FLOW PERSISTS ON TUE AND HIGHS WILL ACTUALLY BE A BIT CHILLIER
AS COLDER AIR ALOFT TRAVERSES ACROSS THE REGION...UPR 30S TO LWR
40S (EVEN MID 30S OVER PARTS OF THE LWR MD/VA ERN SHORE). FLOW
BECOMES SW BY WED AND HIGH TEMPS WILL MODERATE A BIT...BACK INTO
THE LWR 40S NW TO UPR 40S SE.
&&
.AVIATION /08Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS WILL CONTINUE THRU FRIDAY. AS AN ARCTIC FRONT
CROSSES THE REGION MAIN CONCERN LATE THIS MORNING THRU THIS
EVENING WILL BE GUSTY WINDS...ESP ALONG THE COAST. ADDED GUSTS TO
ALL TERMINALS IN THE 20 TO 30 KT RANGE. GUSTS SHOULD BEGIN TO FALL
OFF THIS EVENING.
A LOW PRESSURE SYSTEM MAY IMPACT THE AREA SUN WITH A CHANCE OF
PRECIPITATION AND POSSIBLY LOWERING AVIATION CONDITIONS.
&&
.MARINE...
SCA`S REMAIN IN EFFECT FOR ALL WATERS THRU EARLY FRI MORNING. AGREE
W/ PREV FORECAST ASSESEMENT THAT LOW-END GALES WILL PROBABLY NOT BE
NEEDED FOR THIS EVENT...BUT IT WILL COME CLOSE, ESP THIS AFTN OVR
CENTRAL CHES BAY (VCNTY RAPPAHANOCK LIGHT) AND OUR NRN COASTAL
WATERS. THINK GUSTS AROUND 30 KT WILL WORK WELL.
WITH TEMPS EXPECTED TO FALL BELOW THE FREEZING MARK...AND GUSTY
WINDS CONTINUING OVR THE NRN COASTAL WATERS AT LEAST THRU THE EARLY
EVENING...CANNOT RULE OUT SOME FREEZING SPRAY OCCURING OVERNIGHT. IN
COORDINATION WITH PHI...DECIDED TO ISSUE A FREEZING SPRAY ADVSY FOR
THE OVERNIGHT HRS FOR THE COASTAL WATERS FROM FENWICK ISLND
SOUTHWARD TO PARRAMORE ISLAND.
WINDS START TO DIMINISH FRI THRU SAT AS THE HIGH MOVES OVER THE
MID-ATLANTIC. ANOTHER LOW PRES SYSTEM/FRONT WILL AFFECT THE WATERS
SAT NIGHT THRU MON WITH ANOTHER ROUND OF SCA CONDITIONS ALMOST
CERTAIN. HIGH PRES RETURNS NEXT TUE THRU WED.
&&
.CLIMATE...
VERY COLD WEATHER EXPECTED ON FRIDAY (THE 16TH) INTO THE MORNING OF
SAT (THE 17TH)...BUT SINCE THIS IS CLIMATOLOGICALLY RIGHT AROUND THE
COLDEST TIME OF YEAR...RECORD LOWS AND/OR RECORD LOW MAX
TEMPERATURES APPEAR UNLIKELY AT THE MAIN CLIMATE SITES
(RICHMOND/NORFOLK/SALISBURY). STILL...IT DOES LOOK TO BE THE COLDEST
CONDITIONS WE HAVE EXPERIENCED IN A FEW YEARS:
FCST HIGH FOR FRIDAY:
RICHMOND.....FRI FCST HIGH: 27 F (LAST TIME HIGH WAS COLDER THAN
30 F OCCURRED FEB 6TH 2007)
NORFOLK......FRI FCST HIGH: 29 F (LAST TIME HIGH WAS COLDER THAN
30 F OCCURRED JAN 28TH 2005)
SALISBURY....FRI FCST HIGH: 23 F (LAST TIME HIGH WAS COLDER THAN
25 F OCCURRED FEB 6TH 2007).
REC LOWS SAT JAN 17TH...
RIC... -1 (1977)
ORF... 5 (1977)
SBY... -6 (1965)
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR ANZ630>633-650-
652-654-656-658.
FREEZING SPRAY ADVISORY FROM 7 PM THIS EVENING TO 6 AM EST
FRIDAY FOR ANZ650-652.
&&
$$
SYNOPSIS...ALB/BKH
NEAR TERM...ALB
SHORT TERM...ALB
LONG TERM...ALB/JRL
AVIATION...SMF
MARINE...SMF
CLIMATE...AKQ
000
FXUS61 KRNK 150443
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
1143 PM EST WED JAN 14 2009
.SYNOPSIS...
A COLD FRONT WILL TRAVEL EAST ACROSS THE REGION OVERNIGHT. THIS
FRONT WILL USHER IN THE COLDEST AIR OF THE SEASON SO FAR...ALONG
WITH SNOW ACCUMULATIONS ON WESTERN MOUNTAIN SLOPES...AND GUSTY
WINDS WITH DANGEROUS WIND CHILLS AT TIMES BY WEEKS END.
&&
.NEAR TERM /THROUGH THURSDAY/...
COLD FRONT OVER CENTRAL KY THIS EVENING ON TRACK TO SWEEP EAST
ACROSS THE MOUNTAINS SHORTLY AFTER MIDNIGHT BEFORE EXITING TO THE
EAST BY MORNING. SNOW SHOWERS WITH THIS FEATURE SLOWLY
APPROACHING FROM THE WEST AND SHOULD AFFECT PARTS OF THE UPSLOPE
REGION BY MIDNIGHT. HOWEVER BEST SHOT AT ACCUMULATING SNOW LOOKS
TO BE IN THE POST FRONTAL TIME BETWEEN 08-14Z WHEN DEEPER NW FLOW
TAKES SHAPE ALONG WITH BETTER 85H COLD ADVECTION. LATEST NAM
INDICATES ENOUGH QPF GIVEN LOW LEVEL INSTABILITIES OFF RAOBS TO
COMBO WITH VERY HIGH RATIOS TO LIKELY PRODUCE A FEW INCHES WESTERN
GREENBRIER WHERE ALREADY UPDATED EARLIER TO POST AN ADVISORY INTO
THU. MAY SEE 1-3 INCHES ELSW OVER SE WVA...WITH LESSER AMOUNTS
FARTHER SOUTH WHERE RH NOT QUITE AS DEEP. OTRW KEEPING GRADUAL
INCREASE IN POPS TO LIKELY/CAT ON THE NW SLOPES BY MORNING...LOW
CHANCE OUT TO THE BLUE RIDGE...AND MAINLY DRY OUT EAST. MSAS PRES
RISES SHOWING A GOOD SHOT OF SUBSIDENCE JUST BEHIND THE FRONT THIS
EVENING AND ONCE THIS SWINGS IN AFTER MIDNIGHT SHOULD SEE GUSTS
QUICKLY PICK UP OVERNIGHT. APPEARS SUBSIDENCE AND GRADIENT OF 85H
COLD ADVECTION TO COINCIDE BEST OVER THE HIGHER NW NC RIDGES AFTER
MIDNIGHT WHERE GUSTS TO ADVISORY LEVELS POSSIBLE. HOWEVER THINK
CLOUD CANOPY TO KEEP TEMPS FROM FALLING INTO THE TEENS WEST UNTIL
VERY LATE AS GUIDANCE A BIT FAST ATTM WITH THE COLD AIR. THUS
EXPECT ONLY THE HIGHEST ELEVATIONS TO GO BELOW WIND CHILL ADVISORY
LEVELS SO HOLDING OFF INCLUDING ESPCLY SINCE MAY BE AFTER 12Z WHEN
THE COLDER LOWS ARE REACHED.
AIR MASS BEHIND ARCTIC FRONT THURSDAY WILL BRING COLDEST
TEMPERATURES OF THE SEASON SO FAR...WITH TEMPERATURES NEARLY
STEADY TO DROPPING DURING THE DAY THURSDAY. GRADIENT GRADUALLY
DROPS OFF SO WINDS WILL BEGIN TO DECREASE THROUGHOUT THE DAY.
MOISTURE BECOMES SHALLOW QUICKLY IN NW UPSLOPE LOCATIONS BUT WITH
CYCLONIC FLOW CONTINUING AND LOW LEVELS COLD ENOUGH TO SUPPORT ICE
CRYSTAL GROWTH THROUGH THE DAY...SOME LIGHT ACCUMULATIONS EXPECTED
TO CONTINUE MAINLY IN WV MTNS. USED SNOW TO LIQUID RATIOS OF 20:1
FOR THIS EVENT WITH HIGHEST AMOUNTS ARD 4 INCHES POSSIBLE IN NW
GREENBRIER.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
ALTHOUGH WIND DIRECTION ISN`T PERFECT...ENOUGH OF AN UPSLOPE
COMPONENT COMBINED WITH MOISTURE AND -20C H85 TEMPS SHOULD BE
SUFFICIENT FOR ACCUMULATING SNOW SHOWERS IN GREENBRIER THURSDAY
NIGHT. AN INCH OR LESS WILL FALL IN THE VALLEYS WITH ANOTHER 1 TO 4
ALONG THE HIGHER ELEVATIONS. A SNOW ADVISORY MAY BE NEEDED.
ALSO...AN UPPER WAVE WILL BE DROPPING THROUGH THE CWA...AND ENOUGH
MOISTURE REMAINS AT H85 FOR SOME SNOW SHOWERS TO PENETRATE THE NEW
RIVER VALLEY. H85 MOISTURE OFF THE NAM HINTS AT ONE OF THESE MORE
LOCALIZED BANDS AFFECTING THE ROA/BCB/PSK CORRIDOR EARLY THURSDAY
NIGHT....WHERE A QUICK INCH OR SO IN A VERY COLD REGIME COULD CAUSE
TRAVEL DIFFICULTIES. NEAR ZERO TO SLIGHTLY NEGATIVE NAM H85-H7 SAT
EPV ALSO PROVIDES SUBTLE HINTS. SNOW SHOWERS WANE AS FRIDAY DAWN
NEARS. MODELS ARE TYPICALLY UNABLE TO FORECAST QPF ON SUCH A SMALL
SCALE...SO WILL CARRY SLT CHC POPS ALTHOUGH NAM/GFS CLAIM DRY. A
WIND CHILL ADVISORY WILL BE NEEDED THURSDAY NIGHT AT LEAST FOR THE
WESTERN HALF OF THE CWA AND WILL CONTINUE TO HIGHLIGHT IN THE HWO.
STRONG HIGH PRESSURE MOVES OVERHEAD FRIDAY NIGHT...AND KEPT MAX T AT
LEAST A FEW DEGREES BELOW GUIDANCE CONSIDERING SHALLOW ARCTIC
AIRMASS. BIG QUESTION IS HOW MANY HIGH CLDS SPILL EAST AND WHEN
FRIDAY NIGHT. IF DELAYED THERE COULD BE WIDESPREAD SUBZERO LOWS WEST
OF THE BLUE RIDGE...ESPECIALLY CONSIDERING THAT THERE WILL BE SOME
SNOW ON THE GROUND ALONG THE LWB/BLF/JFZ CORRIDOR.
AT THE END OF THE SHORT RANGE...MUCH VARIABILITY REMAINS CONCERNING
THE TRACK OF ANOTHER CLIPPER SATURDAY NIGHT INTO SUNDAY. ITS
COMMONPLACE FOR DPROG/DT TO INCH SOUTH WITH EACH RUN WITH SUCH A
DEEP EASTERN TROUGH IN PLACE...ESPECIALLY PRECEDED BY AN ARCTIC
OUTBREAK. ALTHOUGH THE TRACK IS FAR ENOUGH NORTH
CURRENTLY...THERE COULD BE A LIGHT ACCUMULATING SNOW ACROSS THE
NORTHERN HALF OF THE CWA IF THIS CLIPPER ARRIVES FARTHER SOUTH.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
NEXT CLIPPER IN THE EASTERN U.S. TROUGH IS PROGGED TO SWING THROUGH
THE CENTRAL APPALACHIANS SUNDAY. MODELS ARE GRADUALLY SHIFTING THE
TRACK OF THIS CLIPPER A LITTLE FURTHER NORTH...SO I HAVE KEPT THE
POPS FOR THE WARM ADVECTION SNOWS AHEAD OF THE CLIPPER CHANCE...WITH
THE LOWEST ACROSS THE SOUTH. DESPITE WARM ADVECTION SUNDAY...
INCREASED CLOUDS WILL HOLD HIGH TEMPS DOWN IN THE 30S...POSSIBLY
UPPER 20S IN THE MTNS. RENEWED COLD ADVECTION SUNDAY NIGHT ON THE
BACK SIDE OF THE CLIPPER LOOKS COLD...BUT NOWHERE NEAR THE ARCTIC
AIR FROM EARLIER IN THE WEEKEND WITH THE SOURCE REGION EASTERN
CANADA. WILL HAVE MAINLY UPSLOPE SNOW SHOWERS IN THE MTNS SUNDAY
NIGHT.
YET ANOTHER CLIPPER-LIKE SHORT WAVE MAY AFFECT THE AREA MONDAY...BUT
LOOKS TO TRACK A LITTLE FURTHER NORTH. HAVE STAYED CLOSE TO HPC
GUIDANCE FOR THIS ONE...WITH LOW POPS CONFINED TO THE MTNS...HIGHEST
IN SE WV. ONCE AGAIN...MORE COLD ADVECTION MONDAY NIGHT BEHIND THIS
CLIPPER...WITH UPSLOPE SNOW SHOWERS IN THE MTNS.
FINALLY...ANOTHER SHORT WAVE SLIDING DOWN THE TROUGH TUESDAY OR
TUESDAY NIGHT MAY BRING MORE SNOW SHOWERS TO THE MTNS. HAVE STAYED
WITH HPC GUIDANCE WHICH FOLLOWS THE SLOWER ECMWF. THIS BRING A COLD
FRONT THROUGH LATE WEDNESDAY...AND ALLOWS HIGH TEMPS TO WARM QUITE
BIT AHEAD OF THE FNT ON WED.
&&
.AVIATION /06Z THURSDAY THROUGH MONDAY/...
CHECK AIRMETS AND SIGMETS FOR TURBULENCE...ICING AND MOUNTAIN
OBSCURATIONS TONIGHT INTO THURSDAY. LOWERING CEILINGS SLOWLY
SPREADING EAST TOWARD THE WESTERN SITES AHEAD OF THE COLD FRONT IN
EASTERN KY ATTM. THIS FRONT WILL CROSS THE REGION AFTER MIDNIGHT WITH
NW WINDS INCREASING AS WELL AS SNOW SHOWERS ALONG THE WESTERN
SLOPES. STILL EXPECTING MVFR CEILINGS WITH MVFR/IFR SNOW SHOWERS
TO DEVELOP 06-08Z BEHIND THE COLD FRONT IN THE MOUNTAINS.
ELSW...MAINLY VFR IN AC...WITH A BKN LAYER OF MVFR/VFR STRATO-CU
POSSIBLE AT KROA BEFORE 12Z. WINDS WILL ALSO INCREASE FROM THE
WEST TO NORTHWEST WITH GUSTS FROM 07-15Z AROUND 40 KNOTS AT HIGHER
ELEVATIONS.
DRIER AIR AND VFR CONDITIONS WILL COME IN ON THURSDAY NIGHT AND
FRIDAY ALONG WITH A LARGE HIGH AND ARCTIC AIR. ANOTHER FRONTAL
BOUNDARY ARRIVES SATURDAY NIGHT INTO SUNDAY WITH ADDITIONAL
WESTERN SLOPE SNOW SHOWERS MAKING FOR POSSIBLE INCLUDING MVFR
CONDITIONS. DRIER AIR SHOULD FOLLOW THE FRONT PRODUCING A VFR
OUTLOOK IN MOST AREAS FOR EARLY NEXT WEEK.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WIND ADVISORY UNTIL 12 PM EST THURSDAY FOR VAZ015.
NC...WIND ADVISORY UNTIL 12 PM EST THURSDAY FOR NCZ001-002-018.
WV...WINTER WEATHER ADVISORY UNTIL 4 PM EST THURSDAY FOR WVZ045.
&&
$$
SYNOPSIS...JH/KK/SK
NEAR TERM...AMS/JH/KK
SHORT TERM...KM
LONG TERM...JJ
AVIATION...AMS/JH/KK
000
FXUS61 KLWX 150249 AAA
AFDLWX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
949 PM EST WED JAN 14 2009
.SYNOPSIS...
AN ALBERTA CLIPPER AND ITS ASSOCIATED COLD FRONT WILL PASS THROUGH
TONIGHT INTO EARLY THURSDAY. BITTERLY COLD CONDITIONS ARE EXPECTED
BEHIND THIS SYSTEM THROUGH THE FIRST PART OF THE WEEKEND. ANOTHER
SYSTEM MAY AFFECT THE REGION LATER THIS WEEKEND INTO EARLY NEXT
WEEK. HIGH PRESSURE WILL BRING DRY AND CHILLY CONDITIONS BY THE
MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /TONIGHT/...
01Z SFC ANALYSIS SHOWS CLIPPER SYSTEM CURRENTLY OVER S OHIO WITH A
W TO E ORIENTED WARM FRONT FROM C OHIO TO THE PA/E WV PANHANDLE
BORDER AND AN ARCTIC COLD FRONT OVER THE OHIO VALLEY STRETCHING SW
ACROSS THE C CONUS. CONVECTIVE SNOW SHOWERS HAVE DEVELOPED ALONG
THE WARM FRONT OVER S OHIO INTO SW PA WHILE IN OUR CWA...LIGHT
SNOW AND FLURRIES HAVE BEEN REPORTED ACROSS THE POTOMAC HIGHLANDS
INTO N MD.
EXPECT LIGHT SNOW AND FLURRIES THROUGH TONIGHT ACROSS THE MTS AND
INTO NORTHERN MD...WHICH IS MAINLY IN AGREEMENT WITH THE 21Z SREF.
SOME SNOW SHOWERS MAY SPREAD AS FAR SOUTH AND EAST AS DC ITNO THE
NORTHERN HALF OF THE CHESAPEAKE BAY. MADE SOME ADJUSTMENTS WITH SKY
COVER TONIGHT TO ACCOUNT FOR OVC SKIES ACROSS THE NORTHERN HALF OF
THE CWA.
ARCTIC COLD FRONT WILL CONTINUE TO PUSH SE AND REACH OUR WESTERN
ZONES BY EARLY THU MORNING. BEHIND THE FRONT...THE FLOW WILL VEER TO
THE NW AND STRONG CAA WILL LEAD TO UPSLOPE SNOW SHOWERS DURING THE
MORNING. SNOW TOTALS OF 2 TO 4 INCHES ARE EXPECTED ACROSS THE
WESTERN SLOPES OF THE POTOMAC HIGHLANDS AND 1 TO 2 IMMEDIATELY TO
THE E. WIND CHILL VALUES OF -5 TO -10F ARE POSSIBLE ACROSS HIGHER
ELEVATIONS OF THE POTOMAC HIGHLANDS AS TEMPERATURES PLUMMET AND
WINDS BECOME GUSTY BEHIND THE FRONT.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
CLIPPER AND ASSOCIATED ARCTIC FRONT WILL MOVE EAST OF THE BAY BY
10Z. ANY LINGERING PRECIPITATION WILL GENERALLY BE RELEGATED TO WEST
OF THE BLUE RIDGE ESPECIALLY UPSLOPE LOCATIONS...ALTHOUGH CANT RULE
OUT A FEW FLURRIES IN THE MORNING ACROSS THE BALTIMORE WASHINGTON
METRO AREA.
NORTHWEST WINDS WILL DRAG IN COLDER AIR INTO THE REGION. WIND CHILL
VALUES WILL BE 5 BELOW OR LESS ACROSS THE HIGHLANDS AND A WIND CHILL
ADVISORY WILL BE IN EFFECT THROUGH THURSDAY AFTERNOON WITH THE
REALIZATION THAT IT WILL LIKELY NEED TO BE EXTENDED TEMPORALLY AND
EXPANDED GEOGRAPHICALLY.
GIVEN NORTHWEST FLOW...WENT A COUPLE DEGREES BELOW MOS FOR MAX T.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
ARCTIC HIGH PRESSURE WILL BUILD OVER THE REGION FOR THE END OF THE
WEEK BRINGING DRY BUT BITTERLY COLD CONDITIONS. TEMPERATURES WILL
AVERAGE 20-25 DEGREES BELOW CLIMO. HAVE WENT BELOW GUIDANCE DURING
THIS TIME WITH THE COLDEST TEMPERATURES PREDICTED FRIDAY NIGHT. MIN
TEMPS FRIDAY NIGHT WILL RANGE FROM BELOW ZERO IN THE POTOMAC
HIGHLANDS TO THE SINGLE DIGITS ACROSS THE WASHINGTON AND BALTIMORE
METROPOLITAN AREAS. AM CONCERNED IT COULD EVEN BE A FEW DEGREES
COLDER GIVEN THE FACT THAT DEWPOINTS ARE PROGGED TO BE BELOW ZERO
FRIDAY NIGHT WITH THE SURFACE HIGH OVERHEAD.
HIGH PRESSURE WILL MOVE OFF THE COAST SATURDAY AND THE NEXT CLIPPER
WILL PASS THROUGH THE REGION LATE IN THE WEEKEND INTO EARLY NEXT
WEEK. SUBTLE DIFFERENCES IN THE UPPER AIR PATTERN AMONG THE LONG
RANGE GUIDANCE HAS LED TO UNCERTAINTY IN TIMING FOR ANY
PRECIPITATION THAT WOULD DEVELOP FROM THIS CLIPPER. FOR NOW...WENT
WITH THE HIGHEST POPS SATURDAY NIGHT AND SUNDAY WHICH IS CLOSER TO
THE 00Z ECMWF SOLUTION RATHER THAN THE GFS WHICH HAS HIGHER POPS
SUNDAY NIGHT AND MONDAY.
LATEST GUIDANCE CONTINUES TO KEEP THE TROUGH OF LOW PRESSURE OVER
THE REGION TUESDAY AND WEDNESDAY BRINGING BELOW NORMAL TEMPERATURES.
THERE MAY BE ENOUGH COLD AIR ALOFT FOR SNOW SHOWERS TUESDAY. WILL
CONTINUE WITH THE SLIGHT CHANCE OF SNOW SHOWERS FOR NOW.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
A CLIPPER SYSTEM AND ASSOCIATED ARCTIC COLD FRONT WILL TRACK
THROUGH THE REGION OVERNIGHT TONIGHT INTO EARLY THU MORNING. MVFR
CIGS ARE EXPECTED ALL TERMINALS EXCEPT IAD AND DCA WHERE ONLY SCT
AT 3 KFT IS FORECASTED. LIGHT SNOW IS EXPECTED AT MRB TONIGHT. 5
TO 10 KT W FLOW THIS EVENING WILL SHIFT TO THE NW AND BECOME GUSTY
ACROSS ALL TERMINALS BY 13Z THU AS THE FRONT MOVES THROUGH. 20 TO
30 KT GUSTS ARE EXPECTED DURING THE DAY ON THU BEFORE WINDS SLOWLY
DIMINISH LATER THU AFTERNOON.
HIGH PRESSURE WILL BRING VFR CONDITIONS THURSDAY NIGHT THROUGH
SATURDAY. AN ALBERTA CLIPPER WILL PASS THROUGH THE TERMINALS LATE IN
THE WEEKEND INTO EARLY NEXT WEEK BRINGING THE NEXT CHANCE FOR
PRECIPITATION.
&&
.MARINE...
A CLIPPER SYSTEM AND ARCTIC FRONT WILL MOVE THROUGH THE WATERS BY
EARLY THURSDAY MORNING. HAVE STARTED THE SCA NOW FOR THE TIDAL
POTOMAC SOUTH OF INDIAN HEAD AND THE LOWER CHESAPEAK BAY AS WINDS
HAVE ALREADY GUSTED TO 20 KTS. SMALL CRAFT CONDITIONS ARE EXPECTED
ACROSS THE REST OF THE WATERS AROUND MIDNIGHT AS THE SYSTEM
APPROACHES.
HIGH PRESSURE WILL APPROACH THE WATERS THURSDAY NIGHT...BUT THERE
WILL BE ENOUGH OF A PRESSURE GRADIENT FOR WEST-NORTHWEST WINDS OVER
20 KNOTS. HAVE ISSUED A SMALL CRAFT ADVISORY THURSDAY NIGHT.
HIGH PRESSURE WILL BUILD OVER THE WATERS FRIDAY INTO SATURDAY. THE
NEXT CLIPPER MAY PASS THROUGH THE WATERS LATE IN THE WEEKEND INTO
EARLY NEXT WEEK BRINGING A CHANCE FOR PRECIPITATION.
&&
.CLIMATE...
VERY COLD WEATHER IS STILL EXPECTED THIS FRIDAY /16 JAN/ INTO
SATURDAY MORNING /17 JAN/. HOWEVER...SINCE THIS IS NEAR THE
CLIMATOLOGICALLY COLDEST TIME OF YEAR...RECORD LOWS AND/OR RECORD
LOW MAXIMUM TEMPERATURES ARE UNLIKELY IN THE BALTIMORE/WASHINGTON
METROPOLITAN AREA. DESPITE GUIDANCE SUGGESTING SLIGHTLY HIGHER
TEMPERATURES ON SATURDAY MORNING...IT STILL DOES LOOK TO BE SOME OF
THE COLDEST AIR IN THE PAST 15 YEARS. PLEASE NOTE THAT IT WAS
SIGNIFICANTLY COLDER DURING A COLD SPELL IN MID JANUARY 1994 AT
BWI/DCA/IAD.
BELOW ARE THE LATEST FORECAST MAXIMA FOR FRIDAY AND MINIMA FOR
SATURDAY AT BWI/DCA/IAD WITH RECENT TIMES TEMPERATURES NEARED THESE
VALUES...AS WELL AS RECORD LOWEST MAX ON 16 JAN AND RECORD LOW ON 17
JAN.
BWI...FRI FCST HIGH: 20 F /HIGH OF 19 F ON JAN 10 2004 AND FEB 4
1996 AND 20 ON FEB 5 2007...RECORD LOW MAXIMUM OF 14 F IN 1893/
DCA...FRI FCST HIGH: 20 F /HIGH OF 17 F ON FEB 4 1996 AND 20 F ON
FEB 3 1996 AND 21 F ON JAN 10 2004...RECORD LOW MAXIMUM OF 15 F IN
1893/
IAD...FRI FCST HIGH: 19 F /HIGH OF 14 F ON FEB 4 1996 AND 19 F ON
JAN 17-18 1997 AND 20 ON FEB 5 2007...RECORD LOW MAXIMUM OF 14 IN
1972 AND 1996/
BWI...SAT FCST LOW: 5 F /LOW OF 1 ON JAN 19 1997 AND 4 ON FEB 6 1996
AND 5 ON JAN 18 2003...RECORD LOW OF -7 IN 1982/
DCA...SAT FCST LOW: 9 F /LOW OF 8 F ON JAN 10 2004 AND 9 ON FEB 4
1996...RECORD LOW OF -5 IN 1982/
IAD...SAT FCST LOW: 3 F /LOW OF 1 F ON DEC 7 2002 AND 3 ON JAN 29
2004...RECORD LOW OF -7 IN 1982/
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...WINTER WEATHER ADVISORY UNTIL 12 PM EST THURSDAY FOR MDZ501-
502.
WIND CHILL ADVISORY FROM 4 AM TO 6 PM EST THURSDAY FOR MDZ501-
502.
VA...WINTER WEATHER ADVISORY UNTIL 12 PM EST THURSDAY FOR VAZ021.
WIND CHILL ADVISORY FROM 4 AM TO 6 PM EST THURSDAY FOR VAZ021.
WV...WINTER WEATHER ADVISORY UNTIL 12 PM EST THURSDAY FOR WVZ054-
501>504.
WIND CHILL ADVISORY FROM 4 AM TO 6 PM EST THURSDAY FOR WVZ054-
501>504.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR ANZ530>532-535.
SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR ANZ533-534-536-
537.
&&
$$
UPDATE...KLEIN
PREV DISC...BPP/BJL
000
FXUS61 KRNK 150229
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
929 PM EST WED JAN 14 2009
.SYNOPSIS...
A COLD FRONT WILL TRAVEL EAST ACROSS THE REGION OVERNIGHT. THIS
FRONT WILL USHER IN THE COLDEST AIR OF THE SEASON SO FAR...ALONG
WITH SNOW ACCUMULATIONS ON WESTERN MOUNTAIN SLOPES...AND GUSTY
WINDS WITH DANGEROUS WIND CHILLS AT TIMES BY WEEKS END.
&&
.NEAR TERM /THROUGH THURSDAY/...
COLD FRONT OVER CENTRAL KY THIS EVENING ON TRACK TO SWEEP EAST
ACROSS THE MOUNTAINS SHORTLY AFTER MIDNIGHT BEFORE EXITING TO THE
EAST BY MORNING. SNOW SHOWERS WITH THIS FEATURE SLOWLY
APPROACHING FROM THE WEST AND SHOULD AFFECT PARTS OF THE UPSLOPE
REGION BY MIDNIGHT. HOWEVER BEST SHOT AT ACCUMULATING SNOW LOOKS
TO BE IN THE POST FRONTAL TIME BETWEEN 08-14Z WHEN DEEPER NW FLOW
TAKES SHAPE ALONG WITH BETTER 85H COLD ADVECTION. LATEST NAM
INDICATES ENOUGH QPF GIVEN LOW LEVEL INSTABILITIES OFF RAOBS TO
COMBO WITH VERY HIGH RATIOS TO LIKELY PRODUCE A FEW INCHES WESTERN
GREENBRIER WHERE ALREADY UPDATED EARLIER TO POST AN ADVISORY INTO
THU. MAY SEE 1-3 INCHES ELSW OVER SE WVA...WITH LESSER AMOUNTS
FARTHER SOUTH WHERE RH NOT QUITE AS DEEP. OTRW KEEPING GRADUAL
INCREASE IN POPS TO LIKELY/CAT ON THE NW SLOPES BY MORNING...LOW
CHANCE OUT TO THE BLUE RIDGE...AND MAINLY DRY OUT EAST. MSAS PRES
RISES SHOWING A GOOD SHOT OF SUBSIDENCE JUST BEHIND THE FRONT THIS
EVENING AND ONCE THIS SWINGS IN AFTER MIDNIGHT SHOULD SEE GUSTS
QUICKLY PICK UP OVERNIGHT. APPEARS SUBSIDENCE AND GRADIENT OF 85H
COLD ADVECTION TO COINCIDE BEST OVER THE HIGHER NW NC RIDGES AFTER
MIDNIGHT WHERE GUSTS TO ADVISORY LEVELS POSSIBLE. HOWEVER THINK
CLOUD CANOPY TO KEEP TEMPS FROM FALLING INTO THE TEENS WEST UNTIL
VERY LATE AS GUIDANCE A BIT FAST ATTM WITH THE COLD AIR. THUS
EXPECT ONLY THE HIGHEST ELEVATIONS TO GO BELOW WIND CHILL ADVISORY
LEVELS SO HOLDING OFF INCLUDING ESPCLY SINCE MAY BE AFTER 12Z WHEN
THE COLDER LOWS ARE REACHED.
AIR MASS BEHIND ARCTIC FRONT THURSDAY WILL BRING COLDEST
TEMPERATURES OF THE SEASON SO FAR...WITH TEMPERATURES NEARLY
STEADY TO DROPPING DURING THE DAY THURSDAY. GRADIENT GRADUALLY
DROPS OFF SO WINDS WILL BEGIN TO DECREASE THROUGHOUT THE DAY.
MOISTURE BECOMES SHALLOW QUICKLY IN NW UPSLOPE LOCATIONS BUT WITH
CYCLONIC FLOW CONTINUING AND LOW LEVELS COLD ENOUGH TO SUPPORT ICE
CRYSTAL GROWTH THROUGH THE DAY...SOME LIGHT ACCUMULATIONS EXPECTED
TO CONTINUE MAINLY IN WV MTNS. USED SNOW TO LIQUID RATIOS OF 20:1
FOR THIS EVENT WITH HIGHEST AMOUNTS ARD 4 INCHES POSSIBLE IN NW
GREENBRIER.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
ALTHOUGH WIND DIRECTION ISN`T PERFECT...ENOUGH OF AN UPSLOPE
COMPONENT COMBINED WITH MOISTURE AND -20C H85 TEMPS SHOULD BE
SUFFICIENT FOR ACCUMULATING SNOW SHOWERS IN GREENBRIER THURSDAY
NIGHT. AN INCH OR LESS WILL FALL IN THE VALLEYS WITH ANOTHER 1 TO 4
ALONG THE HIGHER ELEVATIONS. A SNOW ADVISORY MAY BE NEEDED.
ALSO...AN UPPER WAVE WILL BE DROPPING THROUGH THE CWA...AND ENOUGH
MOISTURE REMAINS AT H85 FOR SOME SNOW SHOWERS TO PENETRATE THE NEW
RIVER VALLEY. H85 MOISTURE OFF THE NAM HINTS AT ONE OF THESE MORE
LOCALIZED BANDS AFFECTING THE ROA/BCB/PSK CORRIDOR EARLY THURSDAY
NIGHT....WHERE A QUICK INCH OR SO IN A VERY COLD REGIME COULD CAUSE
TRAVEL DIFFICULTIES. NEAR ZERO TO SLIGHTLY NEGATIVE NAM H85-H7 SAT
EPV ALSO PROVIDES SUBTLE HINTS. SNOW SHOWERS WANE AS FRIDAY DAWN
NEARS. MODELS ARE TYPICALLY UNABLE TO FORECAST QPF ON SUCH A SMALL
SCALE...SO WILL CARRY SLT CHC POPS ALTHOUGH NAM/GFS CLAIM DRY. A
WIND CHILL ADVISORY WILL BE NEEDED THURSDAY NIGHT AT LEAST FOR THE
WESTERN HALF OF THE CWA AND WILL CONTINUE TO HIGHLIGHT IN THE HWO.
STRONG HIGH PRESSURE MOVES OVERHEAD FRIDAY NIGHT...AND KEPT MAX T AT
LEAST A FEW DEGREES BELOW GUIDANCE CONSIDERING SHALLOW ARCTIC
AIRMASS. BIG QUESTION IS HOW MANY HIGH CLDS SPILL EAST AND WHEN
FRIDAY NIGHT. IF DELAYED THERE COULD BE WIDESPREAD SUBZERO LOWS WEST
OF THE BLUE RIDGE...ESPECIALLY CONSIDERING THAT THERE WILL BE SOME
SNOW ON THE GROUND ALONG THE LWB/BLF/JFZ CORRIDOR.
AT THE END OF THE SHORT RANGE...MUCH VARIABILITY REMAINS CONCERNING
THE TRACK OF ANOTHER CLIPPER SATURDAY NIGHT INTO SUNDAY. ITS
COMMONPLACE FOR DPROG/DT TO INCH SOUTH WITH EACH RUN WITH SUCH A
DEEP EASTERN TROUGH IN PLACE...ESPECIALLY PRECEDED BY AN ARCTIC
OUTBREAK. ALTHOUGH THE TRACK IS FAR ENOUGH NORTH
CURRENTLY...THERE COULD BE A LIGHT ACCUMULATING SNOW ACROSS THE
NORTHERN HALF OF THE CWA IF THIS CLIPPER ARRIVES FARTHER SOUTH.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
NEXT CLIPPER IN THE EASTERN U.S. TROUGH IS PROGGED TO SWING THROUGH
THE CENTRAL APPALACHIANS SUNDAY. MODELS ARE GRADUALLY SHIFTING THE
TRACK OF THIS CLIPPER A LITTLE FURTHER NORTH...SO I HAVE KEPT THE
POPS FOR THE WARM ADVECTION SNOWS AHEAD OF THE CLIPPER CHANCE...WITH
THE LOWEST ACROSS THE SOUTH. DESPITE WARM ADVECTION SUNDAY...
INCREASED CLOUDS WILL HOLD HIGH TEMPS DOWN IN THE 30S...POSSIBLY
UPPER 20S IN THE MTNS. RENEWED COLD ADVECTION SUNDAY NIGHT ON THE
BACK SIDE OF THE CLIPPER LOOKS COLD...BUT NOWHERE NEAR THE ARCTIC
AIR FROM EARLIER IN THE WEEKEND WITH THE SOURCE REGION EASTERN
CANADA. WILL HAVE MAINLY UPSLOPE SNOW SHOWERS IN THE MTNS SUNDAY
NIGHT.
YET ANOTHER CLIPPER-LIKE SHORT WAVE MAY AFFECT THE AREA MONDAY...BUT
LOOKS TO TRACK A LITTLE FURTHER NORTH. HAVE STAYED CLOSE TO HPC
GUIDANCE FOR THIS ONE...WITH LOW POPS CONFINED TO THE MTNS...HIGHEST
IN SE WV. ONCE AGAIN...MORE COLD ADVECTION MONDAY NIGHT BEHIND THIS
CLIPPER...WITH UPSLOPE SNOW SHOWERS IN THE MTNS.
FINALLY...ANOTHER SHORT WAVE SLIDING DOWN THE TROUGH TUESDAY OR
TUESDAY NIGHT MAY BRING MORE SNOW SHOWERS TO THE MTNS. HAVE STAYED
WITH HPC GUIDANCE WHICH FOLLOWS THE SLOWER ECMWF. THIS BRING A COLD
FRONT THROUGH LATE WEDNESDAY...AND ALLOWS HIGH TEMPS TO WARM QUITE
BIT AHEAD OF THE FNT ON WED.
&&
.AVIATION /01Z THURSDAY THROUGH MONDAY/...
CHECK AIRMETS AND SIGMETS FOR TURBULENCE...ICING AND MOUNTAIN
OBSCURATIONS TONIGHT INTO THURSDAY. MID AND HIGH LEVEL CLOUDS
SPREADING EAST INTO WESTERN PORTIONS OF CWA THIS EVENING AHEAD OF
LOW PRESSURE IN THE OHIO VALLEY. THIS LOW WILL CROSS QUICKLY
THROUGH THE OHIO VALLEY THIS EVENING AND WILL PUSH A COLD FRONT
ACROSS THE FORECAST AREA TONIGHT. MVFR CEILINGS WITH MVFR/IFR
SNOW SHOWERS WILL DEVELOP AFTER 06Z BEHIND THE COLD FRONT IN THE
MOUNTAINS. WINDS WILL ALSO INCREASE FROM THE WEST TO NORTHWEST
WITH GUSTS FROM 06-15Z AROUND 40 KNOTS AT HIGHER ELEVATIONS.
DRIER AIR AND VFR CONDITIONS WILL COME IN ON THURSDAY NIGHT AND
FRIDAY ALONG WITH A LARGE HIGH AND ARCTIC AIR. ANOTHER STORM
ARRIVES SATURDAY NIGHT INTO SUNDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WIND ADVISORY UNTIL 12 PM EST THURSDAY FOR VAZ015.
NC...WIND ADVISORY UNTIL 12 PM EST THURSDAY FOR NCZ001-002-018.
WV...WINTER WEATHER ADVISORY UNTIL 4 PM EST THURSDAY FOR WVZ045.
&&
$$
SYNOPSIS...JH/KK/SK
NEAR TERM...AMS/JH/KK
SHORT TERM...KM
LONG TERM...JJ
AVIATION...AMS/JH/KK
000
FXUS61 KAKQ 150143
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
843 PM EST WED JAN 14 2009
.SYNOPSIS...
LOW PRESSURE TRACKS ALONG THE MASON...DIXON LINE TONIGHT...THEN
QUICKLY MOVES EAST OF NEW JERSEY THURSDAY MORNING. THE LOW WILL
DRAG A STRONG COLD FRONT THROUGH THE MID ATLANTIC REGION EARLY
THURSDAY MORNING...AND WILL BE FOLLOWED BY ARCTIC HIGH PRESSURE
AND VERY COLD AIR FOR THURSDAY NIGHT INTO SATURDAY. A CLIPPER
SYSTEM WILL APPROACH FROM THE NORTHWEST SATURDAY NIGHT...THEN
TRACK ACROSS THE MID ATLANTIC REGION LATE SUNDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
EVEN SFC MAP HAS HIGH PRS MOVG OFF THE MID ATLNT COAST. RETURN
FLOW ARND THIS HIGH AND AHEAD OF APPRCHG S/W WILL HELP TO KEEP
TMPS FROM FALLING TO FAR FROM CRNT READINGS. ALSO...SAT LOOP AND
SFC OBS SHOWING A MID LVL CLD DECK APPRCHG FROM THE W...WITH LTST
RUC KEEPING THE MAJORITY OF THESE CLDS ACROSS THE NRN HALF OF FA.
SO EVE UPDATE WAS TO TWEEK GRIDS/ZFP PER CRNT CNDTNS (NOT MUCH
OVERALL CHANGE TO ON GOING FCST). UPSHOT WILL BE A M CLR TO PT
CLDY NIGHT AHEAD ACROSS THE S WITH PT TO M CLDY ACROSS THE N. TMPS
ONLY FALL INTO THE 20S TO L30S SE DUE TO A SW WND INCRG TO BTWN
10-15 MPH & CLOUD COVER.
THE MUCH ADVERTISED CLIPPER IS LCTD ACROSS ERN OHIO WITH ASSCTD WRM
FRNT ETXNDG E INTO VA WITH TRAILING ARCTIC CDFRNT LCTD ACROSS ERN
OHIO/KY/TN. THE LOW MOVES ALONG MASON-DIXON LINE LATE TONITE WITH
TRAILING CDFRNT MOVG INTO WRN HALF OF FA BY 12Z.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
BEHIND THE ARCTIC FRONT...MUCH COLDER AIRMASS TO FOLLOW THU
THROUGH SAT...CERTAINLY THE COLDEST AIR WE`VE EXPERIENCED IN A
COUPLE OF YEARS AT LEAST FOR MOST LOCALES (SEE CLIMATE SECTION
BELOW). STRONG LLVL CAA TO FOLLOW DURING THE DAY ON THU...THOUGH
AS IS TYPICAL THE SHARP COOLING ALOFT DURING THE DAYTIME WILL BE
OFFSET BY THE COMPRESSIONAL WARMING/DEEPENING MIXED LAYER WITH THE
DOWNSLOPING NW FLOW E OF THE FOOTHILLS. THE UPSHOT WILL BE MAX
TEMPS IN THE LOW/MID 30S NRN AREAS TO AROUND 40/LWR 40S SRN
AREAS...AS HIGHS LIKELY WILL BE REACHED BY LATE MORNING/EARLY AFTN
OVER MOST AREAS BEFORE TEMPS BECOME STEADY OR SLOWLY FALL.
MUCH COLDER CONDITIONS WILL BEGIN TO BE FELT THU NIGHT...WITH
DECREASING WINDS AND CLEARING SKIES AWAY FROM THE WATER. MIN TEMPS
ARE EXPECTED TO RANGE FROM THE UPPER SINGLE DIGITS FAR N-NW TO THE
TEENS ELSEWHERE S-SE. FORTUNATELY...BY THE TEMPS FALL TO THESE
LEVELS...THE WINDS WILL HAVE DIMINISHED SIGNIFICANTLY. NEVERTHELESS...
AS THE FCST STANDS NOW...WIND CHILL VALUES MAY GET CLOSE TO ADVISORY
CRITERIA BY FRIDAY MORNING ACROSS THE LWR MD ERN SHORE
(APPROACHING -5F). WILL HAVE TO EVALUATE THIS FURTHER AS THU
NIGHT/FRIDAY MORNING DRAWS NEAR.
OTHERWISE...GIVEN THE STRONG CAA...EXPECT THE DEVELOPMENT OF
BAY/OCEAN EFFECT PLUMES THU NIGHT AND ON FRI. DESPITE THE VERY DRY
AIR ENTRAINMENT INTO THE LOWER LAYERS FROM A SYNOPTIC- SCALE
STANDPOINT...GIVEN THE DEGREE OF COLD AIR (CLOSE TO -20C AT 850
MB)...EXPECT THAT ICE NUCLEI WILL NEVERTHELESS BE PRESENT EVEN IN
VERY SHALLOW CONVECTION. FORTUNATELY...LLVL FLOW APPEARS TO BE
MORE NW THAN N...WHICH WOULD LIKELY KEEP ANY SNOW SHOWER ACTIVITY
OFFSHORE.
HIGHS ON FRI WILL BE THE COLDEST WE`VE SEEN IN 2-4 WINTERS...WHICH
IS IMPRESSIVE WHEN YOU CONSIDER THE ABSENCE OF SNOW COVER. LOCAL
1000-850 MB THICKNESS TOOL (FOR BOTH THE GFS AND NAM) SUGGESTS
LOWER 20S FAR N...MID 20S FOR MUCH OF CENTRAL AND SRN VA...AND
UPPER 20S IN NERN NC. THESE VALUES ARE AT LEAST 5F LOWER THAN THE
LATEST MAV- MET MOS BLEND. FOR NOW...HAVE OPTED TO TREND MAX TEMPS
TOWARD THE LOWER GUIDANCE SUPPORTED BY THE THICKNESS SCHEME.
CENTER OF ARCTIC SFC HIGH PRESSURE MOVES OVER FCST AREA FRI
NGT...SETTING UP COLDEST NGT OF WINTER THUS FAR. RDGS FALL DOWN INTO
THE SINGLE DIGITS ABOVE ZERO IN MANY INLAND LCTNS...MSTLY TEENS
ELSW (AGAIN...WHICH IS QUITE IMPRESSIVE W/O SNOW COVER).
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH PRES QUICKLY MOVES OFFSHORE AND AWAY FROM THE COAST SAT NIGHT
AS A COLD FRONT APPROACHES FROM THE NW. THE FRONT WILL CROSS THE
MID-ATLANTIC REGION SAT NIGHT THRU SUN NIGHT. THE GFS SOLUTION IS
NOW VERY SIMILAR TO THE ECMWF...WITH BOTH MODELS SHOWING SOME
AVAILABLE MOISTURE OVER OUR AREA. MEANWHILE THE GFS ALSO DEVELOPS A
WEAK COASTAL LOW OFF THE S CAROLINA COAST...THEN MOVES IT TO THE NE
AND AWAY FROM CAPE HATTERAS BY SUN NIGHT. WILL KEEP POPS TOPPED OUT
AT 30% AS THIS FEATURE MOVES THRU WITH THE HIGHEST CHANCE OF PRECIP
AND MOISTURE EXPECTED TO BE TO OUR S OVER SERN/ERN NC NEAR THE TRACK
OF THE LOW. TEMPS WILL BE COLD ENOUGH TO SUPPORT ALL SNOW OVER ALL
OF THE FA SAT NIGHT INTO EARLY SUN (LOWS NEAR 20 NW TO NEAR 30 SE).
WITH TEMPS EXPECTED TO RISE INTO THE LWR TO MID 40S DURING THE DAY
SUN EXPECT A TRANSITION TO A RAIN/SNOW MIX LATE MORNING THRU EARLY
AFTERNOON...THEN EVENTUALLY ALL RAIN BY THE LATE AFTERNOON. IT
SHOULD BE NOTED THAT ATTM IT APPEARS THAT ANY PRECIP THAT DOES
MANAGE TO GET SQUEEZED OUT OF THE ATMS IS EXPECTED TO BE LIGHT.
THE FRONT MOVES OFF THE COAST SUN NIGHT...SWEEPING THE LOW FARTHER
OUT TO SEA. PRECIP CHANCES WILL DIMINISH...BUT COULD STILL HAVE SOME
LINGERING/WRAP AROUND MOISTURE ACROSS THE SERN/ERN THIRD OF OUR FA.
SUN NIGHT LOW TEMPS WILL AGAIN BE NEAR 20 NW TO LWR 30S FAR SE...SO
ANY REMAINING PRECIP IS EXPECTED TO BE LIGHT SNOW AS THE LOW DEPARTS.
TROFINESS PERSISTS OVER THE ERN SEABOARD ON MON AND UNDER NW
FLOW/FETCH COULD HAVE SOME (BAY EFFECT) SNOW SHOWERS DEVELOP OVER
THE LWR MD/VA ERN SHORE. HIGH TEMPS MON WILL BE NEAR 40 TO NEAR
45. HIGH PRES RIDGES IN FROM THE SW/W MON NIGHT INTO NEXT WED.
LOWS MON NIGHT WILL BE IN THE UPR TEENS FAR NW TO NEAR 30 FAR SE.
NW FLOW PERSISTS ON TUE AND HIGHS WILL ACTUALLY BE A BIT CHILLIER
AS COLDER AIR ALOFT TRAVERSES ACROSS THE REGION...UPR 30S TO LWR
40S (EVEN MID 30S OVER PARTS OF THE LWR MD/VA ERN SHORE). FLOW
BECOMES SW BY WED AND HIGH TEMPS WILL MODERATE A BIT...BACK INTO
THE LWR 40S NW TO UPR 40S SE.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
VFR CONDITIONS WILL CONTINUE THRU FRIDAY. MAIN CONCERN TONIGHT
THRU FRI WILL BE WINDS...BY LATE TONIGHT WINDS WILL BE FROM THE SW
AND GUSTY AS AN ARTIC FRONT APPROACHES THE AREA. THURS AM WINDS
WILL BECOME GUSTY ESP ALONG THE COAST. A LOW PRESSURE SYSTEM MAY
IMPACT THE AREA SUN WITH A CHANCE OF PRECIPITATION AND POSSIBLY
LOWERING AVIATION CONDITIONS.
&&
.MARINE...
HIGH PRES MOVES TO THE E AWAY FROM THE WATERS THIS EVENING AS AN AREA
OF LOW PRES AND TRAILING COLD FRONT APPROACH THE WATERS. THE LOW
WILL MOVE ACROSS THE WATERS TONIGHT AND WINDS/SEAS WILL RAPIDLY
INCREASE LATE THIS EVENING/AFTER MIDNIGHT AS THE LOW DRAWS CLOSER.
SCA IN EFFECT BEGINNING OVER THE CHES BAY BY LATE EVENING...THEN FOR
ALL COASTAL WATERS AND THE CURRITUCK SND AFTER MIDNIGHT. THE SCA
WILL PERSIST THRU AT LEAST THU NIGHT AS VERY STRONG HIGH PRES
(1045 MB!) BEGINS TO BUILD IN FROM THE W WHICH WILL RESULT IN A
EXCEPTIONALLY TIGHT PRES GRADIENT. HOWEVER MODEL GUIDANCE CONTINUES
TO SUPPORT WINDS BLO GALE LEVELS SO DID NOT GO ANY HIGHER THAN GUSTS
TO 30 KT. LATER SHIFTS WILL CONTINUE TO MONITOR FOR ANY CHANGES.
WINDS START TO DIMINISH FRI THRU SAT AS THE HIGH MOVES OVER THE
MID-ATLANTIC. ANOTHER LOW PRES SYSTEM/FRONT WILL AFFECT THE WATERS
SAT NIGHT THRU MON WITH ANOTHER ROUND OF SCA CONDITIONS ALMOST
CERTAIN. HIGH PRES RETURNS NEXT TUE THRU WED.
&&
.CLIMATE...
VERY COLD WEATHER EXPECTED ON FRIDAY (THE 16TH) INTO THE MORNING OF
SAT (THE 17TH)...BUT SINCE THIS IS CLIMATOLOGICALLY RIGHT AROUND THE
COLDEST TIME OF YEAR...RECORD LOWS AND/OR RECORD LOW MAX
TEMPERATURES APPEAR UNLIKELY AT THE MAIN CLIMATE SITES
(RICHMOND/NORFOLK/SALISBURY). STILL...IT DOES LOOK TO BE THE COLDEST
CONDITIONS WE HAVE EXPERIENCED IN A FEW YEARS:
FCST HIGH FOR FRIDAY:
RICHMOND.....FRI FCST HIGH: 27 F (LAST TIME HIGH WAS COLDER THAN
30 F OCCURRED FEB 6TH 2007)
NORFOLK......FRI FCST HIGH: 27 F (LAST TIME HIGH WAS COLDER THAN 30
F OCCURRED JAN 28TH 2005)
SALISBURY....FRI FCST HIGH: 24 F (LAST TIME HIGH WAS COLDER THAN
25 F OCCURRED FEB 6TH 2007).
REC LOWS SAT JAN 17TH...
RIC... -1 (1977)
ORF... 5 (1977)
SBY... -6 (1965)
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR ANZ630>632.
SMALL CRAFT ADVISORY FROM 1 AM THURSDAY TO 6 AM EST FRIDAY FOR
ANZ633-650-652-654-656-658.
&&
$$
SYNOPSIS...MPR/BKH
NEAR TERM...BKH/MPR
SHORT TERM...BKH
LONG TERM...JRL
AVIATION...CY
MARINE...JRL
CLIMATE...AKQ
000
FXUS61 KRNK 142322
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
622 PM EST WED JAN 14 2009
.SYNOPSIS...
A COLD FRONT WILL TRAVEL EAST ACROSS THE REGION TONIGHT. THIS
FRONT WILL USHER IN THE COLDEST AIR OF THE SEASON SO FAR...ALONG
WITH SNOW ACCUMULATIONS ON WESTERN MOUNTAIN SLOPES...AND GUSTY
WINDS WITH DANGEROUS WIND CHILLS AT TIMES BY WEEKS END.
&&
.NEAR TERM /THROUGH THURSDAY/...
WILL BE SENDING A QUICK UPDATE TO POST A WINTER WEATHER ADVISORY
FOR HIGH ELEVATION SNOW ACROSS GREENBRIER CTY AS WELL AS A WIND
ADVISORY FOR THE NW NC MTN CTYS INCLUDING GRAYSON CTY IN VA INTO THU.
LATEST NAM AND TRAJECTORY PROFILES INDICATE THE POTENTIAL FOR 3-6
INCHES OF SNOW ABOVE 2500 FEET NW GREENBRIER CTY BEHIND THE COLD
FRONT LATER TONIGHT WHEN NW UPSLOPE KICKS IN. ALSO THE ABRUPT
COOLING AT 85H BEHIND THE FRONT MAY COMBINE WITH A QUICK SHOT OF
SUBSIDENCE UNDER THE DEVELOPING INVERSION TO PUSH WINDS ACROSS THE
RIDGES TO AROUND 50 MPH ESPCLY NW NC. SINCE ALSO DURING A FAVORED
NOCTURNAL TIME EXPECT CHANNELING TO ALSO BOOST SPEEDS SO RAISING
AN ADVISORY FOR THOSE SW ZONES. THINK CLOUDS MAY KEEP TEMPS FROM
GOING TOO LOW THUS ALLEVIATING THE WIND CHILLS A BIT OVERNIGHT.
PREVIOUS DISCUSSION BELOW...
LOW PRESSURE OVER ILLINOIS THIS AFTERNOON WILL MOVE EAST TONIGHT AND
PUSHES A COLD FRONT THROUGH THE COUNTY WARNING AREA. CLOUD COVER AND
MOISTURE ASSOCIATED WITH THIS SYSTEM WILL CONTINUE TO SPREAD
EASTWARD TONIGHT. AIRMASS IS QUITE DRY AND IT WILL TAKE TIME TO
MOISTEN UP THE COLUMN. MODELS CONTINUE TO SHOW MOISTURE DEEPENING
ENOUGH BY 03Z FOR WIDESPREAD UPSLOPE SNOW SHOWERS IN THE WEST.
SREF...NAM AND CANADIAN TAPER MOISTURE/POPS OFF QUICKLY HAS ONE
HEADS WEST. PLAYED THE HIGHEST POPS AND SNOW ACCUMULATIONS IN THE
FAVORED WESTERN UPSLOPE AREAS ESPECIALLY THE GREENBRIER VALLEY. THE
RICHEST MOISTURE WITH THIS SYSTEM WILL PASS TO OUR NORTH. WINDS
ALONG AND BEHIND THE FRONT WILL PICK UP TONIGHT WITH PRESSURE RISES
AND 85H WINDS. STRONGEST 850 GRADIENT ACTUALLY FROM SW RIGHT BEFORE
FRONTAL PASSAGE. STILL LOOK LIKE WE COULD GET SOME ISOLD GUSTS OVER
40 MPH ALONG HIGHEST RIDGES BEHIND THE COLD FRONT IN THE MIDDLE OF
THE NIGHT. CROSS SECTIONS SHOWED POTENTIAL FOR WINDS ABOVE 40 KNOTS
AT THE HIGHEST ELEVATIONS FROM 00-09Z. DECIDED NOT TO POST WIND
ADVISORY AT THIS TIME...WITH VALUES JUST BELOW CRITERIA. WIND CHILLS
WILL ALSO BE CLOSE TO ADVISORY LEVELS OVERNIGHT WITH LIMITED
COVERAGE IN THE HIGHEST ELEVATIONS.
AIR MASS BEHIND ARCTIC FRONT THURSDAY WILL BRING COLDEST
TEMPERATURES OF THE SEASON SO FAR...WITH TEMPERATURES NEARLY STEADY
TO DROPPING DURING THE DAY THURSDAY. GRADIENT GRADUALLY DROPS OFF SO
WINDS WILL BEGIN TO DECREASE THROUGHOUT THE DAY. MOISTURE BECOMES
SHALLOW QUICKLY IN NW UPSLOPE LOCATIONS BUT WITH CYCLONIC FLOW
CONTINUING AND LOW LEVELS COLD ENOUGH TO SUPPORT ICE CRYSTAL GROWTH
THROUGH THE DAY...SOME LIGHT ACCUMULATIONS EXPECTED TO CONTINUE
MAINLY IN WV MTNS. USED SNOW TO LIQUID RATIOS OF 20:1 FOR THIS EVENT
WITH HIGHEST AMOUNTS ARD 4 INCHES POSSIBLE IN NW GREENBRIER.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
ALTHOUGH WIND DIRECTION ISN`T PERFECT...ENOUGH OF AN UPSLOPE
COMPONENT COMBINED WITH MOISTURE AND -20C H85 TEMPS SHOULD BE
SUFFICIENT FOR ACCUMULATING SNOW SHOWERS IN GREENBRIER THURSDAY
NIGHT. AN INCH OR LESS WILL FALL IN THE VALLEYS WITH ANOTHER 1 TO 4
ALONG THE HIGHER ELEVATIONS. A SNOW ADVISORY MAY BE NEEDED.
ALSO...AN UPPER WAVE WILL BE DROPPING THROUGH THE CWA...AND ENOUGH
MOISTURE REMAINS AT H85 FOR SOME SNOW SHOWERS TO PENETRATE THE NEW
RIVER VALLEY. H85 MOISTURE OFF THE NAM HINTS AT ONE OF THESE MORE
LOCALIZED BANDS AFFECTING THE ROA/BCB/PSK CORRIDOR EARLY THURSDAY
NIGHT....WHERE A QUICK INCH OR SO IN A VERY COLD REGIME COULD CAUSE
TRAVEL DIFFICULTIES. NEAR ZERO TO SLIGHTLY NEGATIVE NAM H85-H7 SAT
EPV ALSO PROVIDES SUBTLE HINTS. SNOW SHOWERS WANE AS FRIDAY DAWN
NEARS. MODELS ARE TYPICALLY UNABLE TO FORECAST QPF ON SUCH A SMALL
SCALE...SO WILL CARRY SLT CHC POPS ALTHOUGH NAM/GFS CLAIM DRY. A
WIND CHILL ADVISORY WILL BE NEEDED THURSDAY NIGHT AT LEAST FOR THE
WESTERN HALF OF THE CWA AND WILL CONTINUE TO HIGHLIGHT IN THE HWO.
STRONG HIGH PRESSURE MOVES OVERHEAD FRIDAY NIGHT...AND KEPT MAX T AT
LEAST A FEW DEGREES BELOW GUIDANCE CONSIDERING SHALLOW ARCTIC
AIRMASS. BIG QUESTION IS HOW MANY HIGH CLDS SPILL EAST AND WHEN
FRIDAY NIGHT. IF DELAYED THERE COULD BE WIDESPREAD SUBZERO LOWS WEST
OF THE BLUE RIDGE...ESPECIALLY CONSIDERING THAT THERE WILL BE SOME
SNOW ON THE GROUND ALONG THE LWB/BLF/JFZ CORRIDOR.
AT THE END OF THE SHORT RANGE...MUCH VARIABILITY REMAINS CONCERNING
THE TRACK OF ANOTHER CLIPPER SATURDAY NIGHT INTO SUNDAY. ITS
COMMONPLACE FOR DPROG/DT TO INCH SOUTH WITH EACH RUN WITH SUCH A
DEEP EASTERN TROUGH IN PLACE...ESPECIALLY PRECEDED BY AN ARCTIC
OUTBREAK. ALTHOUGH THE TRACK IS FAR ENOUGH NORTH
CURRENTLY...THERE COULD BE A LIGHT ACCUMULATING SNOW ACROSS THE
NORTHERN HALF OF THE CWA IF THIS CLIPPER ARRIVES FARTHER SOUTH.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
NEXT CLIPPER IN THE EASTERN U.S. TROUGH IS PROGGED TO SWING THROUGH
THE CENTRAL APPALACHIANS SUNDAY. MODELS ARE GRADUALLY SHIFTING THE
TRACK OF THIS CLIPPER A LITTLE FURTHER NORTH...SO I HAVE KEPT THE
POPS FOR THE WARM ADVECTION SNOWS AHEAD OF THE CLIPPER CHANCE...WITH
THE LOWEST ACROSS THE SOUTH. DESPITE WARM ADVECTION SUNDAY...
INCREASED CLOUDS WILL HOLD HIGH TEMPS DOWN IN THE 30S...POSSIBLY
UPPER 20S IN THE MTNS. RENEWED COLD ADVECTION SUNDAY NIGHT ON THE
BACK SIDE OF THE CLIPPER LOOKS COLD...BUT NOWHERE NEAR THE ARCTIC
AIR FROM EARLIER IN THE WEEKEND WITH THE SOURCE REGION EASTERN
CANADA. WILL HAVE MAINLY UPSLOPE SNOW SHOWERS IN THE MTNS SUNDAY
NIGHT.
YET ANOTHER CLIPPER-LIKE SHORT WAVE MAY AFFECT THE AREA MONDAY...BUT
LOOKS TO TRACK A LITTLE FURTHER NORTH. HAVE STAYED CLOSE TO HPC
GUIDANCE FOR THIS ONE...WITH LOW POPS CONFINED TO THE MTNS...HIGHEST
IN SE WV. ONCE AGAIN...MORE COLD ADVECTION MONDAY NIGHT BEHIND THIS
CLIPPER...WITH UPSLOPE SNOW SHOWERS IN THE MTNS.
FINALLY...ANOTHER SHORT WAVE SLIDING DOWN THE TROUGH TUESDAY OR
TUESDAY NIGHT MAY BRING MORE SNOW SHOWERS TO THE MTNS. HAVE STAYED
WITH HPC GUIDANCE WHICH FOLLOWS THE SLOWER ECMWF. THIS BRING A COLD
FRONT THROUGH LATE WEDNESDAY...AND ALLOWS HIGH TEMPS TO WARM QUITE
BIT AHEAD OF THE FNT ON WED.
&&
.AVIATION /23Z WEDNESDAY THROUGH MONDAY/...
CHECK AIRMETS AND SIGMETS FOR TURBULENCE...ICING AND MOUNTAIN
OBSCURATIONS TONIGHT INTO THURSDAY. MID AND HIGH LEVEL CLOUDS
SPREADING EAST INTO WESTERN PORTIONS OF CWA THIS EVENING AHEAD OF
LOW PRESSURE IN THE OHIO VALLEY. THIS LOW WILL CROSS QUICKLY
THROUGH THE OHIO VALLEY THIS EVENING AND WILL PUSH A COLD FRONT
ACROSS THE FORECAST AREA TONIGHT. MVFR CEILINGS WITH MVFR/IFR
SNOW SHOWERS WILL DEVELOP AFTER 06Z BEHIND THE COLD FRONT IN THE
MOUNTAINS. WINDS WILL ALSO INCREASE FROM THE WEST TO NORTHWEST
WITH GUSTS FROM 06-15Z AROUND 40 KNOTS AT HIGHER ELEVATIONS.
DRIER AIR AND VFR CONDITIONS WILL COME IN ON THURSDAY NIGHT AND
FRIDAY ALONG WITH A LARGE HIGH AND ARCTIC AIR. ANOTHER STORM
ARRIVES SATURDAY NIGHT INTO SUNDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WIND ADVISORY UNTIL 12 PM EST THURSDAY FOR VAZ015.
NC...WIND ADVISORY UNTIL 12 PM EST THURSDAY FOR NCZ001-002-018.
WV...WINTER WEATHER ADVISORY UNTIL 4 PM EST THURSDAY FOR WVZ045.
&&
$$
SYNOPSIS...KK/SK
NEAR TERM...AMS/JH/KK
SHORT TERM...KM
LONG TERM...JJ
AVIATION...AMS/JH/KK
000
FXUS61 KRNK 142234 AAA
AFDRNK
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BLACKSBURG VA
533 PM EST WED JAN 14 2009
.SYNOPSIS...
A COLD FRONT WILL TRAVEL EAST ACROSS THE REGION TONIGHT. THIS
FRONT WILL USHER IN THE COLDEST AIR OF THE SEASON SO FAR...ALONG
WITH SOME LIGHT SNOW ACCUMULATIONS ON WESTERN MOUNTAIN
SLOPES...AND GUSTY WINDS WITH DANGEROUS WIND CHILLS AT TIMES.
&&
.NEAR TERM /THROUGH THURSDAY/...
WILL BE SENDING A QUICK UPDATE TO POST A WINTER WEATHER ADVISORY
FOR HIGH ELEVATION SNOW ACROSS GREENBRIER CTY AS WELL AS A WIND
ADVISORY FOR THE NW NC MTN CTYS INCLUDING GRAYSON CTY IN VA INTO THU.
LATEST NAM AND TRAJECTORY PROFILES INDICATE THE POTENTIAL FOR 3-6
INCHES OF SNOW ABOVE 2500 FEET NW GREENBRIER CTY BEHIND THE COLD
FRONT LATER TONIGHT WHEN NW UPSLOPE KICKS IN. ALSO THE ABRUPT
COOLING AT 85H BEHIND THE FRONT MAY COMBINE WITH A QUICK SHOT OF
SUBSIDENCE UNDER THE DEVELOPING INVERSION TO PUSH WINDS ACROSS THE
RIDGES TO AROUND 50 MPH ESPCLY NW NC. SINCE ALSO DURING A FAVORED
NOCTURNAL TIME EXPECT CHANNELING TO ALSO BOOST SPEEDS SO RAISING
AN ADVISORY FOR THOSE SW ZONES. THINK CLOUDS MAY KEEP TEMPS FROM
GOING TOO LOW THUS ALLEVIATING THE WIND CHILLS A BIT OVERNIGHT.
PREVIOUS DISCUSSION BELOW...
LOW PRESSURE OVER ILLINOIS THIS AFTERNOON WILL MOVE EAST TONIGHT AND
PUSHES A COLD FRONT THROUGH THE COUNTY WARNING AREA. CLOUD COVER AND
MOISTURE ASSOCIATED WITH THIS SYSTEM WILL CONTINUE TO SPREAD
EASTWARD TONIGHT. AIRMASS IS QUITE DRY AND IT WILL TAKE TIME TO
MOISTEN UP THE COLUMN. MODELS CONTINUE TO SHOW MOISTURE DEEPENING
ENOUGH BY 03Z FOR WIDESPREAD UPSLOPE SNOW SHOWERS IN THE WEST.
SREF...NAM AND CANADIAN TAPER MOISTURE/POPS OFF QUICKLY HAS ONE
HEADS WEST. PLAYED THE HIGHEST POPS AND SNOW ACCUMULATIONS IN THE
FAVORED WESTERN UPSLOPE AREAS ESPECIALLY THE GREENBRIER VALLEY. THE
RICHEST MOISTURE WITH THIS SYSTEM WILL PASS TO OUR NORTH. WINDS
ALONG AND BEHIND THE FRONT WILL PICK UP TONIGHT WITH PRESSURE RISES
AND 85H WINDS. STRONGEST 850 GRADIENT ACTUALLY FROM SW RIGHT BEFORE
FRONTAL PASSAGE. STILL LOOK LIKE WE COULD GET SOME ISOLD GUSTS OVER
40 MPH ALONG HIGHEST RIDGES BEHIND THE COLD FRONT IN THE MIDDLE OF
THE NIGHT. CROSS SECTIONS SHOWED POTENTIAL FOR WINDS ABOVE 40 KNOTS
AT THE HIGHEST ELEVATIONS FROM 00-09Z. DECIDED NOT TO POST WIND
ADVISORY AT THIS TIME...WITH VALUES JUST BELOW CRITERIA. WIND CHILLS
WILL ALSO BE CLOSE TO ADVISORY LEVELS OVERNIGHT WITH LIMITED
COVERAGE IN THE HIGHEST ELEVATIONS.
AIR MASS BEHIND ARCTIC FRONT THURSDAY WILL BRING COLDEST
TEMPERATURES OF THE SEASON SO FAR...WITH TEMPERATURES NEARLY STEADY
TO DROPPING DURING THE DAY THURSDAY. GRADIENT GRADUALLY DROPS OFF SO
WINDS WILL BEGIN TO DECREASE THROUGHOUT THE DAY. MOISTURE BECOMES
SHALLOW QUICKLY IN NW UPSLOPE LOCATIONS BUT WITH CYCLONIC FLOW
CONTINUING AND LOW LEVELS COLD ENOUGH TO SUPPORT ICE CRYSTAL GROWTH
THROUGH THE DAY...SOME LIGHT ACCUMULATIONS EXPECTED TO CONTINUE
MAINLY IN WV MTNS. USED SNOW TO LIQUID RATIOS OF 20:1 FOR THIS EVENT
WITH HIGHEST AMOUNTS ARD 4 INCHES POSSIBLE IN NW GREENBRIER.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
ALTHOUGH WIND DIRECTION ISN`T PERFECT...ENOUGH OF AN UPSLOPE
COMPONENT COMBINED WITH MOISTURE AND -20C H85 TEMPS SHOULD BE
SUFFICIENT FOR ACCUMULATING SNOW SHOWERS IN GREENBRIER THURSDAY
NIGHT. AN INCH OR LESS WILL FALL IN THE VALLEYS WITH ANOTHER 1 TO 4
ALONG THE HIGHER ELEVATIONS. A SNOW ADVISORY MAY BE NEEDED.
ALSO...AN UPPER WAVE WILL BE DROPPING THROUGH THE CWA...AND ENOUGH
MOISTURE REMAINS AT H85 FOR SOME SNOW SHOWERS TO PENETRATE THE NEW
RIVER VALLEY. H85 MOISTURE OFF THE NAM HINTS AT ONE OF THESE MORE
LOCALIZED BANDS AFFECTING THE ROA/BCB/PSK CORRIDOR EARLY THURSDAY
NIGHT....WHERE A QUICK INCH OR SO IN A VERY COLD REGIME COULD CAUSE
TRAVEL DIFFICULTIES. NEAR ZERO TO SLIGHTLY NEGATIVE NAM H85-H7 SAT
EPV ALSO PROVIDES SUBTLE HINTS. SNOW SHOWERS WANE AS FRIDAY DAWN
NEARS. MODELS ARE TYPICALLY UNABLE TO FORECAST QPF ON SUCH A SMALL
SCALE...SO WILL CARRY SLT CHC POPS ALTHOUGH NAM/GFS CLAIM DRY. A
WIND CHILL ADVISORY WILL BE NEEDED THURSDAY NIGHT AT LEAST FOR THE
WESTERN HALF OF THE CWA AND WILL CONTINUE TO HIGHLIGHT IN THE HWO.
STRONG HIGH PRESSURE MOVES OVERHEAD FRIDAY NIGHT...AND KEPT MAX T AT
LEAST A FEW DEGREES BELOW GUIDANCE CONSIDERING SHALLOW ARCTIC
AIRMASS. BIG QUESTION IS HOW MANY HIGH CLDS SPILL EAST AND WHEN
FRIDAY NIGHT. IF DELAYED THERE COULD BE WIDESPREAD SUBZERO LOWS WEST
OF THE BLUE RIDGE...ESPECIALLY CONSIDERING THAT THERE WILL BE SOME
SNOW ON THE GROUND ALONG THE LWB/BLF/JFZ CORRIDOR.
AT THE END OF THE SHORT RANGE...MUCH VARIABILITY REMAINS CONCERNING
THE TRACK OF ANOTHER CLIPPER SATURDAY NIGHT INTO SUNDAY. ITS
COMMONPLACE FOR DPROG/DT TO INCH SOUTH WITH EACH RUN WITH SUCH A
DEEP EASTERN TROUGH IN PLACE...ESPECIALLY PRECEDED BY AN ARCTIC
OUTBREAK. ALTHOUGH THE TRACK IS FAR ENOUGH NORTH
CURRENTLY...THERE COULD BE A LIGHT ACCUMULATING SNOW ACROSS THE
NORTHERN HALF OF THE CWA IF THIS CLIPPER ARRIVES FARTHER SOUTH.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
NEXT CLIPPER IN THE EASTERN U.S. TROUGH IS PROGGED TO SWING THROUGH
THE CENTRAL APPALACHIANS SUNDAY. MODELS ARE GRADUALLY SHIFTING THE
TRACK OF THIS CLIPPER A LITTLE FURTHER NORTH...SO I HAVE KEPT THE
POPS FOR THE WARM ADVECTION SNOWS AHEAD OF THE CLIPPER CHANCE...WITH
THE LOWEST ACROSS THE SOUTH. DESPITE WARM ADVECTION SUNDAY...
INCREASED CLOUDS WILL HOLD HIGH TEMPS DOWN IN THE 30S...POSSIBLY
UPPER 20S IN THE MTNS. RENEWED COLD ADVECTION SUNDAY NIGHT ON THE
BACK SIDE OF THE CLIPPER LOOKS COLD...BUT NOWHERE NEAR THE ARCTIC
AIR FROM EARLIER IN THE WEEKEND WITH THE SOURCE REGION EASTERN
CANADA. WILL HAVE MAINLY UPSLOPE SNOW SHOWERS IN THE MTNS SUNDAY
NIGHT.
YET ANOTHER CLIPPER-LIKE SHORT WAVE MAY AFFECT THE AREA MONDAY...BUT
LOOKS TO TRACK A LITTLE FURTHER NORTH. HAVE STAYED CLOSE TO HPC
GUIDANCE FOR THIS ONE...WITH LOW POPS CONFINED TO THE MTNS...HIGHEST
IN SE WV. ONCE AGAIN...MORE COLD ADVECTION MONDAY NIGHT BEHIND THIS
CLIPPER...WITH UPSLOPE SNOW SHOWERS IN THE MTNS.
FINALLY...ANOTHER SHORT WAVE SLIDING DOWN THE TROUGH TUESDAY OR
TUESDAY NIGHT MAY BRING MORE SNOW SHOWERS TO THE MTNS. HAVE STAYED
WITH HPC GUIDANCE WHICH FOLLOWS THE SLOWER ECMWF. THIS BRING A COLD
FRONT THROUGH LATE WEDNESDAY...AND ALLOWS HIGH TEMPS TO WARM QUITE
BIT AHEAD OF THE FNT ON WED.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
CHECK AIRMETS AND SIGMETS FOR TURBULENCE...ICING AND MOUNTAIN
OBSCURATIONS THIS AFTERNOON AND TONIGHT. MID AND HIGH LEVEL CLOUDS
SPREADING EAST INTO WESTERN PORTIONS OF CWA THIS AFTERNOON AHEAD OF
LOW PRESSURE IN THE OHIO VALLEY. THIS LOW WILL CROSS QUICKLY THROUGH
THE OHIO VALLEY THIS AFTERNOON AND WILL PUSH A COLD FRONT ACROSS THE
FORECAST AREA THIS EVENING. MVFR CEILINGS WITH MVFR/IFR SNOW SHOWERS
WILL DEVELOP AFTER 06Z BEHIND THE COLD FRONT IN THE MOUNTAINS. WINDS
WILL ALSO INCREASE FROM THE WEST TO NORTHWEST WITH GUSTS FROM 06-12Z
AROUND 40 KNOTS AT HIGHER ELEVATIONS.
DRIER AIR AND VFR CONDITIONS WILL COME IN ON THURSDAY NIGHT AND
FRIDAY ALONG WITH A LARGE HIGH AND ARCTIC AIR. ANOTHER STORM
ARRIVES SATURDAY NIGHT INTO SUNDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...WIND ADVISORY FROM 9 PM THIS EVENING TO 12 PM EST THURSDAY FOR
VAZ015.
NC...WIND ADVISORY FROM 9 PM THIS EVENING TO 12 PM EST THURSDAY FOR
NCZ001-002-018.
WV...WINTER WEATHER ADVISORY FROM 9 PM THIS EVENING TO 4 PM EST
THURSDAY FOR WVZ045.
&&
$$
SYNOPSIS...KK/SK
NEAR TERM...AMS/JH/KK
SHORT TERM...KM
LONG TERM...JJ
AVIATION...AMS/KK
000
FXUS61 KAKQ 142228 CCA
AFDAKQ
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE WAKEFIELD VA
526 PM EST WED JAN 14 2009
.SYNOPSIS...
HIGH PRESSURE MOVES OFFSHORE TONIGHT. LOW PRESSURE WILL TRACK
ALONG THE MASON...DIXON LINE TONIGHT...THEN QUICKLY SCOOT OFF THE
JERSEY SHORE THURSDAY MORNING. THE LOW WILL DRAG A STRONG COLD
FRONT THROUGH THE MID ATLANTIC REGION TONIGHT AND EARLY THURSDAY
MORNING...AND WILL BE FOLLOWED BY ARCTIC HIGH PRESSURE AND VERY
COLD AIR FOR THURSDAY NIGHT INTO SATURDAY. A CLIPPER SYSTEM WILL
APPROACH FROM THE NORTHWEST SATURDAY NIGHT...THEN TRACK ACROSS
THE MID ATLANTIC REGION LATE SUNDAY. HIGH PRESSURE RETURNS FROM
THE WEST ON MONDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
THE MUCH ADVERTISED CLIPPER SYSTEM IS CURRENTLY TRAVERSING THE
MIDWEST REGION PER THE LATEST SFC ANALYSIS. ARCTIC AIRMASS BEHIND
THE FRONT IS WELL DEPICTED ON STLT IR IMAGERY...GIVEN THE DEGREE
OF COLD AIR AND (THUS) IR ENHANCEMENT.
AT MOST...EXPECT INCREASING HIGH-BASED CLOUDINESS TONIGHT WITH THE
PASSAGE OF THE COLD FRONT...MAINLY OVER THE NRN ZONES...CLOSER TO
THE SFC LOW AND AXIS OF DEEPER MOISTURE...AND WHERE DOWNSLOPE
DRYING EFFECTS ARE TYPICALLY NOT AS PRONOUNCED.
MAINLY CLEAR SKIES EARLY (ESPECIALLY ERN AREAS) WILL ALLOW TEMPS
TO DIP FAIRLY QUICKLY TOWARD AND JUST AFTER SUNSET. LATER THIS
EVENING AND OVERNIGHT...S TO SW SFC WINDS WILL BUILD TO 10-15 MPH
AHEAD OF THE FRONT. THIS ALONG WITH ANY INCREASE IN CLOUD COVER
WILL GENERATE A WELL MIXED BOUNDARY LAYER...THUS ALLOWING FOR
STEADY (OR EVEN SLOWLY RISING) TEMPS LATE THIS EVENING AND OVERNIGHT.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
BEHIND THE ARCTIC FRONT...MUCH COLDER AIRMASS TO FOLLOW THU
THROUGH SAT...CERTAINLY THE COLDEST AIR WE`VE EXPERIENCED IN A
COUPLE OF YEARS AT LEAST FOR MOST LOCALES (SEE CLIMATE SECTION
BELOW). STRONG LLVL CAA TO FOLLOW DURING THE DAY ON THU...THOUGH
AS IS TYPICAL THE SHARP COOLING ALOFT DURING THE DAYTIME WILL BE
OFFSET BY THE COMPRESSIONAL WARMING/DEEPENING MIXED LAYER WITH THE
DOWNSLOPING NW FLOW E OF THE FOOTHILLS. THE UPSHOT WILL BE MAX
TEMPS IN THE LOW/MID 30S NRN AREAS TO AROUND 40/LWR 40S SRN
AREAS...AS HIGHS LIKELY WILL BE REACHED BY LATE MORNING/EARLY AFTN
OVER MOST AREAS BEFORE TEMPS BECOME STEADY OR SLOWLY FALL.
MUCH COLDER CONDITIONS WILL BEGIN TO BE FELT THU NIGHT...WITH
DECREASING WINDS AND CLEARING SKIES AWAY FROM THE WATER. MIN TEMPS
ARE EXPECTED TO RANGE FROM THE UPPER SINGLE DIGITS FAR N-NW TO THE
TEENS ELSEWHERE S-SE. FORTUNATELY...BY THE TEMPS FALL TO THESE
LEVELS...THE WINDS WILL HAVE DIMINISHED SIGNIFICANTLY. NEVERTHELESS...
AS THE FCST STANDS NOW...WIND CHILL VALUES MAY GET CLOSE TO ADVISORY
CRITERIA BY FRIDAY MORNING ACROSS THE LWR MD ERN SHORE
(APPROACHING -5F). WILL HAVE TO EVALUATE THIS FURTHER AS THU
NIGHT/FRIDAY MORNING DRAWS NEAR.
OTHERWISE...GIVEN THE STRONG CAA...EXPECT THE DEVELOPMENT OF
BAY/OCEAN EFFECT PLUMES THU NIGHT AND ON FRI. DESPITE THE VERY DRY
AIR ENTRAINMENT INTO THE LOWER LAYERS FROM A SYNOPTIC- SCALE
STANDPOINT...GIVEN THE DEGREE OF COLD AIR (CLOSE TO -20C AT 850
MB)...EXPECT THAT ICE NUCLEI WILL NEVERTHELESS BE PRESENT EVEN IN
VERY SHALLOW CONVECTION. FORTUNATELY...LLVL FLOW APPEARS TO BE
MORE NW THAN N...WHICH WOULD LIKELY KEEP ANY SNOW SHOWER ACTIVITY
OFFSHORE.
HIGHS ON FRI WILL BE THE COLDEST WE`VE SEEN IN 2-4 WINTERS...WHICH
IS IMPRESSIVE WHEN YOU CONSIDER THE ABSENCE OF SNOW COVER. LOCAL
1000-850 MB THICKNESS TOOL (FOR BOTH THE GFS AND NAM) SUGGESTS
LOWER 20S FAR N...MID 20S FOR MUCH OF CENTRAL AND SRN VA...AND
UPPER 20S IN NERN NC. THESE VALUES ARE AT LEAST 5F LOWER THAN THE
LATEST MAV- MET MOS BLEND. FOR NOW...HAVE OPTED TO TREND MAX TEMPS
TOWARD THE LOWER GUIDANCE SUPPORTED BY THE THICKNESS SCHEME.
CENTER OF ARCTIC SFC HIGH PRESSURE MOVES OVER FCST AREA FRI
NGT...SETTING UP COLDEST NGT OF WINTER THUS FAR. RDGS FALL DOWN INTO
THE SINGLE DIGITS ABOVE ZERO IN MANY INLAND LCTNS...MSTLY TEENS
ELSW (AGAIN...WHICH IS QUITE IMPRESSIVE W/O SNOW COVER).
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH PRES QUICKLY MOVES OFFSHORE AND AWAY FROM THE COAST SAT NIGHT
AS A COLD FRONT APPROACHES FROM THE NW. THE FRONT WILL CROSS THE
MID-ATLANTIC REGION SAT NIGHT THRU SUN NIGHT. THE GFS SOLUTION IS
NOW VERY SIMILAR TO THE ECMWF...WITH BOTH MODELS SHOWING SOME
AVAILABLE MOISTURE OVER OUR AREA. MEANWHILE THE GFS ALSO DEVELOPS A
WEAK COASTAL LOW OFF THE S CAROLINA COAST...THEN MOVES IT TO THE NE
AND AWAY FROM CAPE HATTERAS BY SUN NIGHT. WILL KEEP POPS TOPPED OUT
AT 30% AS THIS FEATURE MOVES THRU WITH THE HIGHEST CHANCE OF PRECIP
AND MOISTURE EXPECTED TO BE TO OUR S OVER SERN/ERN NC NEAR THE TRACK
OF THE LOW. TEMPS WILL BE COLD ENOUGH TO SUPPORT ALL SNOW OVER ALL
OF THE FA SAT NIGHT INTO EARLY SUN (LOWS NEAR 20 NW TO NEAR 30 SE).
WITH TEMPS EXPECTED TO RISE INTO THE LWR TO MID 40S DURING THE DAY
SUN EXPECT A TRANSITION TO A RAIN/SNOW MIX LATE MORNING THRU EARLY
AFTERNOON...THEN EVENTUALLY ALL RAIN BY THE LATE AFTERNOON. IT
SHOULD BE NOTED THAT ATTM IT APPEARS THAT ANY PRECIP THAT DOES
MANAGE TO GET SQUEEZED OUT OF THE ATMS IS EXPECTED TO BE LIGHT.
THE FRONT MOVES OFF THE COAST SUN NIGHT...SWEEPING THE LOW FARTHER
OUT TO SEA. PRECIP CHANCES WILL DIMINISH...BUT COULD STILL HAVE SOME
LINGERING/WRAP AROUND MOISTURE ACROSS THE SERN/ERN THIRD OF OUR FA.
SUN NIGHT LOW TEMPS WILL AGAIN BE NEAR 20 NW TO LWR 30S FAR SE...SO
ANY REMAINING PRECIP IS EXPECTED TO BE LIGHT SNOW AS THE LOW DEPARTS.
TROFINESS PERSISTS OVER THE ERN SEABOARD ON MON AND UNDER NW
FLOW/FETCH COULD HAVE SOME (BAY EFFECT) SNOW SHOWERS DEVELOP OVER
THE LWR MD/VA ERN SHORE. HIGH TEMPS MON WILL BE NEAR 40 TO NEAR
45. HIGH PRES RIDGES IN FROM THE SW/W MON NIGHT INTO NEXT WED.
LOWS MON NIGHT WILL BE IN THE UPR TEENS FAR NW TO NEAR 30 FAR SE.
NW FLOW PERSISTS ON TUE AND HIGHS WILL ACTUALLY BE A BIT CHILLIER
AS COLDER AIR ALOFT TRAVERSES ACROSS THE REGION...UPR 30S TO LWR
40S (EVEN MID 30S OVER PARTS OF THE LWR MD/VA ERN SHORE). FLOW
BECOMES SW BY WED AND HIGH TEMPS WILL MODERATE A BIT...BACK INTO
THE LWR 40S NW TO UPR 40S SE.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
VFR CONDITIONS WILL CONTINUE THRU FRIDAY. MAIN CONCERN TONIGHT
THRU FRI WILL BE WINDS...BY LATE TONIGHT WINDS WILL BE FROM THE SW
AND GUSTY AS AN ARTIC FRONT APPROACHES THE AREA. THURS AM WINDS
WILL BECOME GUSTY ESP ALONG THE COAST. A LOW PRESSURE SYSTEM MAY
IMPACT THE AREA SUN WITH A CHANCE OF PRECIPITATION AND POSSIBLY
LOWERING AVIATION CONDITIONS.
&&
.MARINE...
HIGH PRES MOVES TO THE E AWAY FROM THE WATERS THIS EVENING AS AN AREA
OF LOW PRES AND TRAILING COLD FRONT APPROACH THE WATERS. THE LOW
WILL MOVE ACROSS THE WATERS TONIGHT AND WINDS/SEAS WILL RAPIDLY
INCREASE LATE THIS EVENING/AFTER MIDNIGHT AS THE LOW DRAWS CLOSER.
SCA IN EFFECT BEGINNING OVER THE CHES BAY BY LATE EVENING...THEN FOR
ALL COASTAL WATERS AND THE CURRITUCK SND AFTER MIDNIGHT. THE SCA
WILL PERSIST THRU AT LEAST THU NIGHT AS VERY STRONG HIGH PRES
(1045 MB!) BEGINS TO BUILD IN FROM THE W WHICH WILL RESULT IN A
EXCEPTIONALLY TIGHT PRES GRADIENT. HOWEVER MODEL GUIDANCE CONTINUES
TO SUPPORT WINDS BLO GALE LEVELS SO DID NOT GO ANY HIGHER THAN GUSTS
TO 30 KT. LATER SHIFTS WILL CONTINUE TO MONITOR FOR ANY CHANGES.
WINDS START TO DIMINISH FRI THRU SAT AS THE HIGH MOVES OVER THE
MID-ATLANTIC. ANOTHER LOW PRES SYSTEM/FRONT WILL AFFECT THE WATERS
SAT NIGHT THRU MON WITH ANOTHER ROUND OF SCA CONDITIONS ALMOST
CERTAIN. HIGH PRES RETURNS NEXT TUE THRU WED.
&&
.CLIMATE...
VERY COLD WEATHER EXPECTED ON FRIDAY (THE 16TH) INTO THE MORNING OF
SAT (THE 17TH)...BUT SINCE THIS IS CLIMATOLOGICALLY RIGHT AROUND THE
COLDEST TIME OF YEAR...RECORD LOWS AND/OR RECORD LOW MAX
TEMPERATURES APPEAR UNLIKELY AT THE MAIN CLIMATE SITES
(RICHMOND/NORFOLK/SALISBURY). STILL...IT DOES LOOK TO BE THE COLDEST
CONDITIONS WE HAVE EXPERIENCED IN A FEW YEARS:
FCST HIGH FOR FRIDAY:
RICHMOND.....FRI FCST HIGH: 27 F (LAST TIME HIGH WAS COLDER THAN
30 F OCCURRED FEB 6TH 2007)
NORFOLK......FRI FCST HIGH: 27 F (LAST TIME HIGH WAS COLDER THAN 30
F OCCURRED JAN 28TH 2005)
SALISBURY....FRI FCST HIGH: 24 F (LAST TIME HIGH WAS COLDER THAN
25 F OCCURRED FEB 6TH 2007).
REC LOWS SAT JAN 17TH...
RIC... -1 (1977)
ORF... 5 (1977)
SBY... -6 (1965)
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 AM EST
FRIDAY FOR ANZ630>632.
SMALL CRAFT ADVISORY FROM 1 AM THURSDAY TO 6 AM EST FRIDAY FOR
ANZ633-650-652-654-656-658.
&&
$$
SYNOPSIS...BKH
NEAR TERM...BKH
SHORT TERM...BKH
LONG TERM...JRL
AVIATION...CY
MARINE...JRL
CLIMATE...AKQ
000
FXUS61 KAKQ 142228 CCA
AFDAKQ
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE WAKEFIELD VA
526 PM EST WED JAN 14 2009
.SYNOPSIS...
HIGH PRESSURE MOVES OFFSHORE TONIGHT. LOW PRESSURE WILL TRACK
ALONG THE MASON...DIXON LINE TONIGHT...THEN QUICKLY SCOOT OFF THE
JERSEY SHORE THURSDAY MORNING. THE LOW WILL DRAG A STRONG COLD
FRONT THROUGH THE MID ATLANTIC REGION TONIGHT AND EARLY THURSDAY
MORNING...AND WILL BE FOLLOWED BY ARCTIC HIGH PRESSURE AND VERY
COLD AIR FOR THURSDAY NIGHT INTO SATURDAY. A CLIPPER SYSTEM WILL
APPROACH FROM THE NORTHWEST SATURDAY NIGHT...THEN TRACK ACROSS
THE MID ATLANTIC REGION LATE SUNDAY. HIGH PRESSURE RETURNS FROM
THE WEST ON MONDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
THE MUCH ADVERTISED CLIPPER SYSTEM IS CURRENTLY TRAVERSING THE
MIDWEST REGION PER THE LATEST SFC ANALYSIS. ARCTIC AIRMASS BEHIND
THE FRONT IS WELL DEPICTED ON STLT IR IMAGERY...GIVEN THE DEGREE
OF COLD AIR AND (THUS) IR ENHANCEMENT.
AT MOST...EXPECT INCREASING HIGH-BASED CLOUDINESS TONIGHT WITH THE
PASSAGE OF THE COLD FRONT...MAINLY OVER THE NRN ZONES...CLOSER TO
THE SFC LOW AND AXIS OF DEEPER MOISTURE...AND WHERE DOWNSLOPE
DRYING EFFECTS ARE TYPICALLY NOT AS PRONOUNCED.
MAINLY CLEAR SKIES EARLY (ESPECIALLY ERN AREAS) WILL ALLOW TEMPS
TO DIP FAIRLY QUICKLY TOWARD AND JUST AFTER SUNSET. LATER THIS
EVENING AND OVERNIGHT...S TO SW SFC WINDS WILL BUILD TO 10-15 MPH
AHEAD OF THE FRONT. THIS ALONG WITH ANY INCREASE IN CLOUD COVER
WILL GENERATE A WELL MIXED BOUNDARY LAYER...THUS ALLOWING FOR
STEADY (OR EVEN SLOWLY RISING) TEMPS LATE THIS EVENING AND OVERNIGHT.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
BEHIND THE ARCTIC FRONT...MUCH COLDER AIRMASS TO FOLLOW THU
THROUGH SAT...CERTAINLY THE COLDEST AIR WE`VE EXPERIENCED IN A
COUPLE OF YEARS AT LEAST FOR MOST LOCALES (SEE CLIMATE SECTION
BELOW). STRONG LLVL CAA TO FOLLOW DURING THE DAY ON THU...THOUGH
AS IS TYPICAL THE SHARP COOLING ALOFT DURING THE DAYTIME WILL BE
OFFSET BY THE COMPRESSIONAL WARMING/DEEPENING MIXED LAYER WITH THE
DOWNSLOPING NW FLOW E OF THE FOOTHILLS. THE UPSHOT WILL BE MAX
TEMPS IN THE LOW/MID 30S NRN AREAS TO AROUND 40/LWR 40S SRN
AREAS...AS HIGHS LIKELY WILL BE REACHED BY LATE MORNING/EARLY AFTN
OVER MOST AREAS BEFORE TEMPS BECOME STEADY OR SLOWLY FALL.
MUCH COLDER CONDITIONS WILL BEGIN TO BE FELT THU NIGHT...WITH
DECREASING WINDS AND CLEARING SKIES AWAY FROM THE WATER. MIN TEMPS
ARE EXPECTED TO RANGE FROM THE UPPER SINGLE DIGITS FAR N-NW TO THE
TEENS ELSEWHERE S-SE. FORTUNATELY...BY THE TEMPS FALL TO THESE
LEVELS...THE WINDS WILL HAVE DIMINISHED SIGNIFICANTLY. NEVERTHELESS...
AS THE FCST STANDS NOW...WIND CHILL VALUES MAY GET CLOSE TO ADVISORY
CRITERIA BY FRIDAY MORNING ACROSS THE LWR MD ERN SHORE
(APPROACHING -5F). WILL HAVE TO EVALUATE THIS FURTHER AS THU
NIGHT/FRIDAY MORNING DRAWS NEAR.
OTHERWISE...GIVEN THE STRONG CAA...EXPECT THE DEVELOPMENT OF
BAY/OCEAN EFFECT PLUMES THU NIGHT AND ON FRI. DESPITE THE VERY DRY
AIR ENTRAINMENT INTO THE LOWER LAYERS FROM A SYNOPTIC- SCALE
STANDPOINT...GIVEN THE DEGREE OF COLD AIR (CLOSE TO -20C AT 850
MB)...EXPECT THAT ICE NUCLEI WILL NEVERTHELESS BE PRESENT EVEN IN
VERY SHALLOW CONVECTION. FORTUNATELY...LLVL FLOW APPEARS TO BE
MORE NW THAN N...WHICH WOULD LIKELY KEEP ANY SNOW SHOWER ACTIVITY
OFFSHORE.
HIGHS ON FRI WILL BE THE COLDEST WE`VE SEEN IN 2-4 WINTERS...WHICH
IS IMPRESSIVE WHEN YOU CONSIDER THE ABSENCE OF SNOW COVER. LOCAL
1000-850 MB THICKNESS TOOL (FOR BOTH THE GFS AND NAM) SUGGESTS
LOWER 20S FAR N...MID 20S FOR MUCH OF CENTRAL AND SRN VA...AND
UPPER 20S IN NERN NC. THESE VALUES ARE AT LEAST 5F LOWER THAN THE
LATEST MAV- MET MOS BLEND. FOR NOW...HAVE OPTED TO TREND MAX TEMPS
TOWARD THE LOWER GUIDANCE SUPPORTED BY THE THICKNESS SCHEME.
CENTER OF ARCTIC SFC HIGH PRESSURE MOVES OVER FCST AREA FRI
NGT...SETTING UP COLDEST NGT OF WINTER THUS FAR. RDGS FALL DOWN INTO
THE SINGLE DIGITS ABOVE ZERO IN MANY INLAND LCTNS...MSTLY TEENS
ELSW (AGAIN...WHICH IS QUITE IMPRESSIVE W/O SNOW COVER).
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH PRES QUICKLY MOVES OFFSHORE AND AWAY FROM THE COAST SAT NIGHT
AS A COLD FRONT APPROACHES FROM THE NW. THE FRONT WILL CROSS THE
MID-ATLANTIC REGION SAT NIGHT THRU SUN NIGHT. THE GFS SOLUTION IS
NOW VERY SIMILAR TO THE ECMWF...WITH BOTH MODELS SHOWING SOME
AVAILABLE MOISTURE OVER OUR AREA. MEANWHILE THE GFS ALSO DEVELOPS A
WEAK COASTAL LOW OFF THE S CAROLINA COAST...THEN MOVES IT TO THE NE
AND AWAY FROM CAPE HATTERAS BY SUN NIGHT. WILL KEEP POPS TOPPED OUT
AT 30% AS THIS FEATURE MOVES THRU WITH THE HIGHEST CHANCE OF PRECIP
AND MOISTURE EXPECTED TO BE TO OUR S OVER SERN/ERN NC NEAR THE TRACK
OF THE LOW. TEMPS WILL BE COLD ENOUGH TO SUPPORT ALL SNOW OVER ALL
OF THE FA SAT NIGHT INTO EARLY SUN (LOWS NEAR 20 NW TO NEAR 30 SE).
WITH TEMPS EXPECTED TO RISE INTO THE LWR TO MID 40S DURING THE DAY
SUN EXPECT A TRANSITION TO A RAIN/SNOW MIX LATE MORNING THRU EARLY
AFTERNOON...THEN EVENTUALLY ALL RAIN BY THE LATE AFTERNOON. IT
SHOULD BE NOTED THAT ATTM IT APPEARS THAT ANY PRECIP THAT DOES
MANAGE TO GET SQUEEZED OUT OF THE ATMS IS EXPECTED TO BE LIGHT.
THE FRONT MOVES OFF THE COAST SUN NIGHT...SWEEPING THE LOW FARTHER
OUT TO SEA. PRECIP CHANCES WILL DIMINISH...BUT COULD STILL HAVE SOME
LINGERING/WRAP AROUND MOISTURE ACROSS THE SERN/ERN THIRD OF OUR FA.
SUN NIGHT LOW TEMPS WILL AGAIN BE NEAR 20 NW TO LWR 30S FAR SE...SO
ANY REMAINING PRECIP IS EXPECTED TO BE LIGHT SNOW AS THE LOW DEPARTS.
TROFINESS PERSISTS OVER THE ERN SEABOARD ON MON AND UNDER NW
FLOW/FETCH COULD HAVE SOME (BAY EFFECT) SNOW SHOWERS DEVELOP OVER
THE LWR MD/VA ERN SHORE. HIGH TEMPS MON WILL BE NEAR 40 TO NEAR
45. HIGH PRES RIDGES IN FROM THE SW/W MON NIGHT INTO NEXT WED.
LOWS MON NIGHT WILL BE IN THE UPR TEENS FAR NW TO NEAR 30 FAR SE.
NW FLOW PERSISTS ON TUE AND HIGHS WILL ACTUALLY BE A BIT CHILLIER
AS COLDER AIR ALOFT TRAVERSES ACROSS THE REGION...UPR 30S TO LWR
40S (EVEN MID 30S OVER PARTS OF THE LWR MD/VA ERN SHORE). FLOW
BECOMES SW BY WED AND HIGH TEMPS WILL MODERATE A BIT...BACK INTO
THE LWR 40S NW TO UPR 40S SE.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
VFR CONDITIONS WILL CONTINUE THRU FRIDAY. MAIN CONCERN TONIGHT
THRU FRI WILL BE WINDS...BY LATE TONIGHT WINDS WILL BE FROM THE SW
AND GUSTY AS AN ARTIC FRONT APPROACHES THE AREA. THURS AM WINDS
WILL BECOME GUSTY ESP ALONG THE COAST. A LOW PRESSURE SYSTEM MAY
IMPACT THE AREA SUN WITH A CHANCE OF PRECIPITATION AND POSSIBLY
LOWERING AVIATION CONDITIONS.
&&
.MARINE...
HIGH PRES MOVES TO THE E AWAY FROM THE WATERS THIS EVENING AS AN AREA
OF LOW PRES AND TRAILING COLD FRONT APPROACH THE WATERS. THE LOW
WILL MOVE ACROSS THE WATERS TONIGHT AND WINDS/SEAS WILL RAPIDLY
INCREASE LATE THIS EVENING/AFTER MIDNIGHT AS THE LOW DRAWS CLOSER.
SCA IN EFFECT BEGINNING OVER THE CHES BAY BY LATE EVENING...THEN FOR
ALL COASTAL WATERS AND THE CURRITUCK SND AFTER MIDNIGHT. THE SCA
WILL PERSIST THRU AT LEAST THU NIGHT AS VERY STRONG HIGH PRES
(1045 MB!) BEGINS TO BUILD IN FROM THE W WHICH WILL RESULT IN A
EXCEPTIONALLY TIGHT PRES GRADIENT. HOWEVER MODEL GUIDANCE CONTINUES
TO SUPPORT WINDS BLO GALE LEVELS SO DID NOT GO ANY HIGHER THAN GUSTS
TO 30 KT. LATER SHIFTS WILL CONTINUE TO MONITOR FOR ANY CHANGES.
WINDS START TO DIMINISH FRI THRU SAT AS THE HIGH MOVES OVER THE
MID-ATLANTIC. ANOTHER LOW PRES SYSTEM/FRONT WILL AFFECT THE WATERS
SAT NIGHT THRU MON WITH ANOTHER ROUND OF SCA CONDITIONS ALMOST
CERTAIN. HIGH PRES RETURNS NEXT TUE THRU WED.
&&
.CLIMATE...
VERY COLD WEATHER EXPECTED ON FRIDAY (THE 16TH) INTO THE MORNING OF
SAT (THE 17TH)...BUT SINCE THIS IS CLIMATOLOGICALLY RIGHT AROUND THE
COLDEST TIME OF YEAR...RECORD LOWS AND/OR RECORD LOW MAX
TEMPERATURES APPEAR UNLIKELY AT THE MAIN CLIMATE SITES
(RICHMOND/NORFOLK/SALISBURY). STILL...IT DOES LOOK TO BE THE COLDEST
CONDITIONS WE HAVE EXPERIENCED IN A FEW YEARS:
FCST HIGH FOR FRIDAY:
RICHMOND.....FRI FCST HIGH: 27 F (LAST TIME HIGH WAS COLDER THAN
30 F OCCURRED FEB 6TH 2007)
NORFOLK......FRI FCST HIGH: 27 F (LAST TIME HIGH WAS COLDER THAN 30
F OCCURRED JAN 28TH 2005)
SALISBURY....FRI FCST HIGH: 24 F (LAST TIME HIGH WAS COLDER THAN
25 F OCCURRED FEB 6TH 2007).
REC LOWS SAT JAN 17TH...
RIC... -1 (1977)
ORF... 5 (1977)
SBY... -6 (1965)
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 AM EST
FRIDAY FOR ANZ630>632.
SMALL CRAFT ADVISORY FROM 1 AM THURSDAY TO 6 AM EST FRIDAY FOR
ANZ633-650-652-654-656-658.
&&
$$
SYNOPSIS...BKH
NEAR TERM...BKH
SHORT TERM...BKH
LONG TERM...JRL
AVIATION...CY
MARINE...JRL
CLIMATE...AKQ
000
FXUS61 KAKQ 142112
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
412 PM EST WED JAN 14 2009
.SYNOPSIS...
HIGH PRESSURE MOVES OFFSHORE TONIGHT. LOW PRESSURE WILL TRACK
ALONG THE MASON...DIXON LINE TONIGHT...THEN QUICKLY SCOOT OFF THE
JERSEY SHORE THURSDAY MORNING. THE LOW WILL DRAG A STRONG COLD
FRONT THROUGH THE MID ATLANTIC REGION TONIGHT AND EARLY THURSDAY
MORNING...AND WILL BE FOLLOWED BY ARCTIC HIGH PRESSURE AND VERY
COLD AIR FOR THURSDAY NIGHT INTO SATURDAY. A CLIPPER SYSTEM WILL
APPROACH FROM THE NORTHWEST SATURDAY NIGHT...THEN TRACK ACROSS
THE MID ATLANTIC REGION LATE SUNDAY. HIGH PRESSURE RETURNS FROM
THE WEST ON MONDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
THE MUCH ADVERTISED CLIPPER SYSTEM IS CURRENTLY TRAVERSING THE
MIDWEST REGION PER THE LATEST SFC ANALYSIS. ARCTIC AIRMASS BEHIND
THE FRONT IS WELL DEPICTED ON STLT IR IMAGERY...GIVEN THE DEGREE
OF COLD AIR AND (THUS) IR ENHANCEMENT.
AT MOST...EXPECT INCREASING HIGH-BASED CLOUDINESS TONIGHT WITH THE
PASSAGE OF THE COLD FRONT...MAINLY OVER THE NRN ZONES...CLOSER TO
THE SFC LOW AND AXIS OF DEEPER MOISTURE...AND WHERE DOWNSLOPE
DRYING EFFECTS ARE TYPICALLY NOT AS PRONOUNCED.
MAINLY CLEAR SKIES EARLY (ESPECIALLY ERN AREAS) WILL ALLOW TEMPS
TO DIP FAIRLY QUICKLY TOWARD AND JUST AFTER SUNSET. LATER THIS
EVENING AND OVERNIGHT...S TO SW SFC WINDS WILL BUILD TO 10-15 MPH
AHEAD OF THE FRONT. THIS ALONG WITH ANY INCREASE IN CLOUD COVER
WILL GENERATE A WELL MIXED BOUNDARY LAYER...THUS ALLOWING FOR
STEADY (OR EVEN SLOWLY RISING) TEMPS LATE THIS EVENING AND OVERNIGHT.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
BEHIND THE ARCTIC FRONT...MUCH COLDER AIRMASS TO FOLLOW THU
THROUGH SAT...CERTAINLY THE COLDEST AIR WE`VE EXPERIENCED IN A
COUPLE OF YEARS AT LEAST FOR MOST LOCALES (SEE CLIMATE SECTION
BELOW). STRONG LLVL CAA TO FOLLOW DURING THE DAY ON THU...THOUGH
AS IS TYPICAL THE SHARP COOLING ALOFT DURING THE DAYTIME WILL BE
OFFSET BY THE COMPRESSIONAL WARMING/DEEPENING MIXED LAYER WITH THE
DOWNSLOPING NW FLOW E OF THE FOOTHILLS. THE UPSHOT WILL BE MAX
TEMPS IN THE LOW/MID 30S NRN AREAS TO AROUND 40/LWR 40S SRN
AREAS...AS HIGHS LIKELY WILL BE REACHED BY LATE MORNING/EARLY AFTN
OVER MOST AREAS BEFORE TEMPS BECOME STEADY OR SLOWLY FALL.
MUCH COLDER CONDITIONS WILL BEGIN TO BE FELT THU NIGHT...WITH
DECREASING WINDS AND CLEARING SKIES AWAY FROM THE WATER. MIN TEMPS
ARE EXPECTED TO RANGE FROM THE UPPER SINGLE DIGITS FAR N-NW TO THE
TEENS ELSEWHERE S-SE. FORTUNATELY...BY THE TEMPS FALL TO THESE
LEVELS...THE WINDS WILL HAVE DIMINISHED SIGNIFICANTLY. NEVERTHELESS...
AS THE FCST STANDS NOW...WIND CHILL VALUES MAY GET CLOSE TO ADVISORY
CRITERIA BY FRIDAY MORNING ACROSS THE LWR MD ERN SHORE
(APPROACHING -5F). WILL HAVE TO EVALUATE THIS FURTHER AS THU
NIGHT/FRIDAY MORNING DRAWS NEAR.
OTHERWISE...GIVEN THE STRONG CAA...EXPECT THE DEVELOPMENT OF
BAY/OCEAN EFFECT PLUMES THU NIGHT AND ON FRI. DESPITE THE VERY DRY
AIR ENTRAINMENT INTO THE LOWER LAYERS FROM A SYNOPTIC- SCALE
STANDPOINT...GIVEN THE DEGREE OF COLD AIR (CLOSE TO -20C AT 850
MB)...EXPECT THAT ICE NUCLEI WILL NEVERTHELESS BE PRESENT EVEN IN
VERY SHALLOW CONVECTION. FORTUNATELY...LLVL FLOW APPEARS TO BE
MORE NW THAN N...WHICH WOULD LIKELY KEEP ANY SNOW SHOWER ACTIVITY
OFFSHORE.
HIGHS ON FRI WILL BE THE COLDEST WE`VE SEEN IN 2-4 WINTERS...WHICH
IS IMPRESSIVE WHEN YOU CONSIDER THE ABSENCE OF SNOW COVER. LOCAL
1000-850 MB THICKNESS TOOL (FOR BOTH THE GFS AND NAM) SUGGESTS
LOWER 20S FAR N...MID 20S FOR MUCH OF CENTRAL AND SRN VA...AND
UPPER 20S IN NERN NC. THESE VALUES ARE AT LEAST 5F LOWER THAN THE
LATEST MAV- MET MOS BLEND. FOR NOW...HAVE OPTED TO TREND MAX TEMPS
TOWARD THE LOWER GUIDANCE SUPPORTED BY THE THICKNESS SCHEME.
CENTER OF ARCTIC SFC HIGH PRESSURE MOVES OVER FCST AREA FRI
NGT...SETTING UP COLDEST NGT OF WINTER THUS FAR. RDGS FALL DOWN INTO
THE SINGLE DIGITS ABOVE ZERO IN MANY INLAND LCTNS...MSTLY TEENS
ELSW (AGAIN...WHICH IS QUITE IMPRESSIVE W/O SNOW COVER).
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
HIGH PRES QUICKLY MOVES OFFSHORE AND AWAY FROM THE COAST SAT NIGHT
AS A COLD FRONT APPROACHES FROM THE NW. THE FRONT WILL CROSS THE
MID-ATLANTIC REGION SAT NIGHT THRU SUN NIGHT. THE GFS SOLUTION IS
NOW VERY SIMILAR TO THE ECMWF...WITH BOTH MODELS SHOWING SOME
AVAILABLE MOISTURE OVER OUR AREA. MEANWHILE THE GFS ALSO DEVELOPS A
WEAK COASTAL LOW OFF THE S CAROLINA COAST...THEN MOVES IT TO THE NE
AND AWAY FROM CAPE HATTERAS BY SUN NIGHT. WILL KEEP POPS TOPPED OUT
AT 30% AS THIS FEATURE MOVES THRU WITH THE HIGHEST CHANCE OF PRECIP
AND MOISTURE EXPECTED TO BE TO OUR S OVER SERN/ERN NC NEAR THE TRACK
OF THE LOW. TEMPS WILL BE COLD ENOUGH TO SUPPORT ALL SNOW OVER ALL
OF THE FA SAT NIGHT INTO EARLY SUN (LOWS NEAR 20 NW TO NEAR 30 SE).
WITH TEMPS EXPECTED TO RISE INTO THE LWR TO MID 40S DURING THE DAY
SUN EXPECT A TRANSITION TO A RAIN/SNOW MIX LATE MORNING THRU EARLY
AFTERNOON...THEN EVENTUALLY ALL RAIN BY THE LATE AFTERNOON. IT
SHOULD BE NOTED THAT ATTM IT APPEARS THAT ANY PRECIP THAT DOES
MANAGE TO GET SQUEEZED OUT OF THE ATMS IS EXPECTED TO BE LIGHT.
THE FRONT MOVES OFF THE COAST SUN NIGHT...SWEEPING THE LOW FARTHER
OUT TO SEA. PRECIP CHANCES WILL DIMINISH...BUT COULD STILL HAVE SOME
LINGERING/WRAP AROUND MOISTURE ACROSS THE SERN/ERN THIRD OF OUR FA.
SUN NIGHT LOW TEMPS WILL AGAIN BE NEAR 20 NW TO LWR 30S FAR SE...SO
ANY REMAINING PRECIP IS EXPECTED TO BE LIGHT SNOW AS THE LOW DEPARTS.
TROFINESS PERSISTS OVER THE ERN SEABOARD ON MON AND UNDER NW
FLOW/FETCH COULD HAVE SOME (BAY EFFECT) SNOW SHOWERS) DEVELOP OVER
THE LWR MD/VA ERN SHORE. HIGH TEMPS MON WILL BE NEAR 40 TO NEAR 45.
HIGH PRES RIDGES IN FROM THE SW/W MON NIGHT INTO NEXT WED. LOWS MON
NIGHT WILL BE IN THE UPR TEENS FAR NW TO NEAR 30 FAR SE. NW FLOW
PERSISTS ON TUE AND HIGHS WILL ACTUALLY BE A BIT CHILLIER AS COLDER
AIR ALOFT TRAVERSES ACROSS THE REGION...UPR 30S TO LWR 40S (EVEN MID
30S OVER PARTS OF THE LWR MD/VA ERN SHORE). FLOW BECOMES SW BY WED
AND HIGH TEMPS WILL MODERATE A BIT...BACK INTO THE LWR 40S NW TO UPR
40S SE.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
VFR CONDITIONS WILL
CONTINUE THRU FRIDAY. MAIN CONCERN TONIGHT THRU FRI WILL BE
WINDS...BY LATE TONIGHT WINDS WILL BE FROM THE SW AND GUSTY AS AN
ARTIC FRONT APPROACHES THE AREA. THURS AM WINDS WILL BECOME GUSTY
ESP ALONG THE COAST. A LOW PRESSURE SYSTEM MAY IMPACT THE AREA SUN
WITH A CHANCE OF PRECIPITATION AND POSSIBLY LOWERING AVIATION
CONDITIONS.
&&
.MARINE...
HIGH PRES MOVES TO THE E AWAY FROM THE WATERS THIS EVENING AS AN AREA
OF LOW PRES AND TRAILING COLD FRONT APPROACH THE WATERS. THE LOW
WILL MOVE ACROSS THE WATERS TONIGHT AND WINDS/SEAS WILL RAPIDLY
INCREASE LATE THIS EVENING/AFTER MIDNIGHT AS THE LOW DRAWS CLOSER.
SCA IN EFFECT BEGINNING OVER THE CHES BAY BY LATE EVENING...THEN FOR
ALL COASTAL WATERS AND THE CURRITUCK SND AFTER MIDNIGHT. THE SCA
WILL PERSIST THRU AT LEAST THU NIGHT AS VERY STRONG HIGH PRES
(1045 MB!) BEGINS TO BUILD IN FROM THE W WHICH WILL RESULT IN A
EXCEPTIONALLY TIGHT PRES GRADIENT. HOWEVER MODEL GUIDANCE CONTINUES
TO SUPPORT WINDS BLO GALE LEVELS SO DID NOT GO ANY HIGHER THAN GUSTS
TO 30 KT. LATER SHIFTS WILL CONTINUE TO MONITOR FOR ANY CHANGES.
WINDS START TO DIMINISH FRI THRU SAT AS THE HIGH MOVES OVER THE
MID-ATLANTIC. ANOTHER LOW PRES SYSTEM/FRONT WILL AFFECT THE WATERS
SAT NIGHT THRU MON WITH ANOTHER ROUND OF SCA CONDITIONS ALMOST
CERTAIN. HIGH PRES RETURNS NEXT TUE THRU WED.
&&
.CLIMATE...
VERY COLD WEATHER EXPECTED ON FRIDAY (THE 16TH) INTO THE MORNING OF
SAT (THE 17TH)...BUT SINCE THIS IS CLIMATOLOGICALLY RIGHT AROUND THE
COLDEST TIME OF YEAR...RECORD LOWS AND/OR RECORD LOW MAX
TEMPERATURES APPEAR UNLIKELY AT THE MAIN CLIMATE SITES
(RICHMOND/NORFOLK/SALISBURY). STILL...IT DOES LOOK TO BE THE COLDEST
CONDITIONS WE HAVE EXPERIENCED IN A FEW YEARS:
FCST HIGH FOR FRIDAY:
RICHMOND.....FRI FCST HIGH: 27 F (LAST TIME HIGH WAS COLDER THAN
30 F OCCURRED FEB 6TH 2007)
NORFOLK......FRI FCST HIGH: 27 F (LAST TIME HIGH WAS COLDER THAN 30
F OCCURRED JAN 28TH 2005)
SALISBURY....FRI FCST HIGH: 24 F (LAST TIME HIGH WAS COLDER THAN
25 F OCCURRED FEB 6TH 2007).
REC LOWS SAT JAN 17TH...
RIC... -1 (1977)
ORF... 5 (1977)
SBY... -6 (1965)
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 AM EST
FRIDAY FOR ANZ630>632.
SMALL CRAFT ADVISORY FROM 1 AM THURSDAY TO 6 AM EST FRIDAY FOR
ANZ633-650-652-654-656-658.
&&
$$
SYNOPSIS...BKH
NEAR TERM...BKH
SHORT TERM...BKH
LONG TERM...JRL
AVIATION...CY
MARINE...JRL
CLIMATE...AKQ
000
FXUS61 KAKQ 142058
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
358 PM EST WED JAN 14 2009
.SYNOPSIS...
HIGH PRESSURE MOVES OFFSHORE TONIGHT. LOW PRESSURE WILL TRACK
ALONG THE MASON...DIXON LINE TONIGHT...THEN QUICKLY SCOOT OFF THE
JERSEY SHORE THURSDAY MORNING. THE LOW WILL DRAG A STRONG COLD
FRONT THROUGH THE MID ATLANTIC REGION TONIGHT AND EARLY THURSDAY
MORNING...AND WILL BE FOLLOWED BY ARCTIC HIGH PRESSURE AND VERY
COLD AIR FOR THURSDAY NIGHT INTO SATURDAY. A CLIPPER SYSTEM WILL
APPROACH FROM THE NORTHWEST SATURDAY NIGHT...THEN TRACK ACROSS
THE MID ATLANTIC REGION LATE SUNDAY. HIGH PRESSURE RETURNS FROM
THE WEST ON MONDAY.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
THE MUCH ADVERTISED CLIPPER SYSTEM IS CURRENTLY TRAVERSING THE
MIDWEST REGION PER THE LATEST SFC ANALYSIS. ARCTIC AIRMASS BEHIND
THE FRONT IS WELL DEPICTED ON STLT IR IMAGERY...GIVEN THE DEGREE
OF COLD AIR AND (THUS) IR ENHANCEMENT.
AT MOST...EXPECT INCREASING HIGH-BASED CLOUDINESS TONIGHT WITH THE
PASSAGE OF THE COLD FRONT...MAINLY OVER THE NRN ZONES...CLOSER TO
THE SFC LOW AND AXIS OF DEEPER MOISTURE...AND WHERE DOWNSLOPE
DRYING EFFECTS ARE TYPICALLY NOT AS PRONOUNCED.
MAINLY CLEAR SKIES EARLY (ESPECIALLY ERN AREAS) WILL ALLOW TEMPS
TO DIP FAIRLY QUICKLY TOWARD AND JUST AFTER SUNSET. LATER THIS
EVENING AND OVERNIGHT...S TO SW SFC WINDS WILL BUILD TO 10-15 MPH
AHEAD OF THE FRONT. THIS ALONG WITH ANY INCREASE IN CLOUD COVER
WILL GENERATE A WELL MIXED BOUNDARY LAYER...THUS ALLOWING FOR
STEADY (OR EVEN SLOWLY RISING) TEMPS LATE THIS EVENING AND OVERNIGHT.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
BEHIND THE ARCTIC FRONT...MUCH COLDER AIRMASS TO FOLLOW THU
THROUGH SAT...CERTAINLY THE COLDEST AIR WE`VE EXPERIENCED IN A
COUPLE OF YEARS AT LEAST FOR MOST LOCALES (SEE CLIMATE SECTION
BELOW). STRONG LLVL CAA TO FOLLOW DURING THE DAY ON THU...THOUGH
AS IS TYPICAL THE SHARP COOLING ALOFT DURING THE DAYTIME WILL BE
OFFSET BY THE COMPRESSIONAL WARMING/DEEPENING MIXED LAYER WITH THE
DOWNSLOPING NW FLOW E OF THE FOOTHILLS. THE UPSHOT WILL BE MAX
TEMPS IN THE LOW/MID 30S NRN AREAS TO AROUND 40/LWR 40S SRN
AREAS...AS HIGHS LIKELY WILL BE REACHED BY LATE MORNING/EARLY AFTN
OVER MOST AREAS BEFORE TEMPS BECOME STEADY OR SLOWLY FALL.
MUCH COLDER CONDITIONS WILL BEGIN TO BE FELT THU NIGHT...WITH
DECREASING WINDS AND CLEARING SKIES AWAY FROM THE WATER. MIN TEMPS
ARE EXPECTED TO RANGE FROM THE UPPER SINGLE DIGITS FAR N-NW TO THE
TEENS ELSEWHERE S-SE. FORTUNATELY...BY THE TEMPS FALL TO THESE
LEVELS...THE WINDS WILL HAVE DIMINISHED SIGNIFICANTLY. NEVERTHELESS...
AS THE FCST STANDS NOW...WIND CHILL VALUES MAY GET CLOSE TO ADVISORY
CRITERIA BY FRIDAY MORNING ACROSS THE LWR MD ERN SHORE
(APPROACHING -5F). WILL HAVE TO EVALUATE THIS FURTHER AS THU
NIGHT/FRIDAY MORNING DRAWS NEAR.
OTHERWISE...GIVEN THE STRONG CAA...EXPECT THE DEVELOPMENT OF
BAY/OCEAN EFFECT PLUMES THU NIGHT AND ON FRI. DESPITE THE VERY DRY
AIR ENTRAINMENT INTO THE LOWER LAYERS FROM A SYNOPTIC- SCALE
STANDPOINT...GIVEN THE DEGREE OF COLD AIR (CLOSE TO -20C AT 850
MB)...EXPECT THAT ICE NUCLEI WILL NEVERTHELESS BE PRESENT EVEN IN
VERY SHALLOW CONVECTION. FORTUNATELY...LLVL FLOW APPEARS TO BE
MORE NW THAN N...WHICH WOULD LIKELY KEEP ANY SNOW SHOWER ACTIVITY
OFFSHORE.
HIGHS ON FRI WILL BE THE COLDEST WE`VE SEEN IN 2-4 WINTERS...WHICH
IS IMPRESSIVE WHEN YOU CONSIDER THE ABSENCE OF SNOW COVER. LOCAL
1000-850 MB THICKNESS TOOL (FOR BOTH THE GFS AND NAM) SUGGESTS
LOWER 20S FAR N...MID 20S FOR MUCH OF CENTRAL AND SRN VA...AND
UPPER 20S IN NERN NC. THESE VALUES ARE AT LEAST 5F LOWER THAN THE
LATEST MAV- MET MOS BLEND. FOR NOW...HAVE OPTED TO TREND MAX TEMPS
TOWARD THE LOWER GUIDANCE SUPPORTED BY THE THICKNESS SCHEME.
CENTER OF ARCTIC SFC HIGH PRESSURE MOVES OVER FCST AREA FRI
NGT...SETTING UP COLDEST NGT OF WINTER THUS FAR. RDGS FALL DOWN INTO
THE SINGLE DIGITS ABOVE ZERO IN MANY INLAND LCTNS...MSTLY TEENS
ELSW (AGAIN...WHICH IS QUITE IMPRESSIVE W/O SNOW COVER).
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
HIGH PRES QUICKLY MOVES OFFSHORE AND AWAY FROM THE COAST SAT NIGHT
AS A COLD FRONT APPROACHES FROM THE NW. THE FRONT WILL CROSS THE
MID-ATLANTIC REGION SAT NIGHT THRU SUN NIGHT. THE GFS SOLUTION IS
NOW VERY SIMILAR TO THE ECMWF...WITH BOTH MODELS SHOWING SOME
AVAILABLE MOISTURE OVER OUR AREA. MEANWHILE THE GFS ALSO DEVELOPS A
WEAK COASTAL LOW OFF THE S CAROLINA COAST...THEN MOVES IT TO THE NE
AND AWAY FROM CAPE HATTERAS BY SUN NIGHT. WILL KEEP POPS TOPPED OUT
AT 30% AS THIS FEATURE MOVES THRU WITH THE HIGHEST CHANCE OF PRECIP
AND MOISTURE EXPECTED TO BE TO OUR S OVER SERN/ERN NC NEAR THE TRACK
OF THE LOW. TEMPS WILL BE COLD ENOUGH TO SUPPORT ALL SNOW OVER ALL
OF THE FA SAT NIGHT INTO EARLY SUN (LOWS NEAR 20 NW TO NEAR 30 SE).
WITH TEMPS EXPECTED TO RISE INTO THE LWR TO MID 40S DURING THE DAY
SUN EXPECT A TRANSITION TO A RAIN/SNOW MIX LATE MORNING THRU EARLY
AFTERNOON...THEN EVENTUALLY ALL RAIN BY THE LATE AFTERNOON. IT
SHOULD BE NOTED THAT ATTM IT APPEARS THAT ANY PRECIP THAT DOES
MANAGE TO GET SQUEEZED OUT OF THE ATMS IS EXPECTED TO BE LIGHT.
THE FRONT MOVES OFF THE COAST SUN NIGHT...SWEEPING THE LOW FARTHER
OUT TO SEA. PRECIP CHANCES WILL DIMINISH...BUT COULD STILL HAVE SOME
LINGERING/WRAP AROUND MOISTURE ACROSS THE SERN/ERN THIRD OF OUR FA.
SUN NIGHT LOW TEMPS WILL AGAIN BE NEAR 20 NW TO LWR 30S FAR SE...SO
ANY REMAINING PRECIP IS EXPECTED TO BE LIGHT SNOW AS THE LOW DEPARTS.
TROFINESS PERSISTS OVER THE ERN SEABOARD ON MON AND UNDER NW
FLOW/FETCH COULD HAVE SOME (BAY EFFECT) SNOW SHOWERS) DEVELOP OVER
THE LWR MD/VA ERN SHORE. HIGH TEMPS MON WILL BE NEAR 40 TO NEAR 45.
HIGH PRES RIDGES IN FROM THE SW/W MON NIGHT INTO NEXT WED. LOWS MON
NIGHT WILL BE IN THE UPR TEENS FAR NW TO NEAR 30 FAR SE. NW FLOW
PERSISTS ON TUE AND HIGHS WILL ACTUALLY BE A BIT CHILLIER AS COLDER
AIR ALOFT TRAVERSES ACROSS THE REGION...UPR 30S TO LWR 40S (EVEN MID
30S OVER PARTS OF THE LWR MD/VA ERN SHORE). FLOW BECOMES SW BY WED
AND HIGH TEMPS WILL MODERATE A BIT...BACK INTO THE LWR 40S NW TO UPR
40S SE.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
VFR CONDITIONS WILL
CONTINUE THRU FRIDAY. MAIN CONCERN TONIGHT THRU FRI WILL BE
WINDS...BY LATE TONIGHT WINDS WILL BE FROM THE SW AND GUSTY AS AN
ARTIC FRONT APPROACHES THE AREA. THURS AM WINDS WILL BECOME GUSTY
ESP ALONG THE COAST. A LOW PRESSURE SYSTEM MAY IMPACT THE AREA SUN
WITH A CHANCE OF PRECIPITATION AND POSSIBLY LOWERING AVIATION
CONDITIONS.
&&
.MARINE...
WATERS CAN EXPECT A BRIEF RESPITE THIS AFTN AND EARLY EVENING AS
HIGH PRES BRIEFLY BUILDS IN. THEN SOUTHERLY WINDS BEGIN PICKING UP
ONCE AGAIN LATER TONIGHT. EXPECT YET EVEN COLDER AIR WITH THIS
FROPA...AND THINK THAT MODELS ARE SERIOUSLY UNDERDOING THE WINDS
W/ THIS NEXT EVENT. CERTAINLY LOOKING AT HIGH END SCA`S FOR LATER
TONIGHT INTO EARLY THU...BUT ALSO POSSIBLY LO-END GALES. WILL
ALLOW DAY SHIFT TO MAKE DECISION...ONCE CURRENT HEADLINES HV
EXPIRED.
&&
.CLIMATE...
VERY COLD WEATHER EXPECTED ON FRIDAY (THE 16TH) INTO THE MORNING OF
SAT (THE 17TH)...BUT SINCE THIS IS CLIMATOLOGICALLY RIGHT AROUND THE
COLDEST TIME OF YEAR...RECORD LOWS AND/OR RECORD LOW MAX
TEMPERATURES APPEAR UNLIKELY AT THE MAIN CLIMATE SITES
(RICHMOND/NORFOLK/SALISBURY). STILL...IT DOES LOOK TO BE THE COLDEST
CONDITIONS WE HAVE EXPERIENCED IN A FEW YEARS:
FCST HIGH FOR FRIDAY:
RICHMOND.....FRI FCST HIGH: 27 F (LAST TIME HIGH WAS COLDER THAN
30 F OCCURRED FEB 6TH 2007)
NORFOLK......FRI FCST HIGH: 27 F (LAST TIME HIGH WAS COLDER THAN 30
F OCCURRED JAN 28TH 2005)
SALISBURY....FRI FCST HIGH: 24 F (LAST TIME HIGH WAS COLDER THAN
25 F OCCURRED FEB 6TH 2007).
REC LOWS SAT JAN 17TH...
RIC... -1 (1977)
ORF... 5 (1977)
SBY... -6 (1965)
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 AM EST
FRIDAY FOR ANZ630>632.
SMALL CRAFT ADVISORY FROM 1 AM THURSDAY TO 6 AM EST FRIDAY FOR
ANZ633-650-652-654-656-658.
&&
$$
SYNOPSIS...BKH
NEAR TERM...BKH
SHORT TERM...BKH
LONG TERM...JRL
AVIATION...CY
MARINE...JRL
CLIMATE...AKQ
000
FXUS61 KRNK 142045
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
345 PM EST WED JAN 14 2009
.SYNOPSIS...
A COLD FRONT WILL TRAVEL EAST ACROSS THE REGION TONIGHT. THIS
FRONT WILL USHER IN THE COLDEST AIR OF THE SEASON SO FAR...ALONG
WITH SOME LIGHT SNOW ACCUMULATIONS ON WESTERN MOUNTAIN
SLOPES...AND GUSTY WINDS WITH DANGEROUS WIND CHILLS AT TIMES.
&&
.NEAR TERM /THROUGH THURSDAY/...
LOW PRESSURE OVER ILLINOIS THIS AFTERNOON WILL MOVE EAST TONIGHT AND
PUSHES A COLD FRONT THROUGH THE COUNTY WARNING AREA. CLOUD COVER AND
MOISTURE ASSOCIATED WITH THIS SYSTEM WILL CONTINUE TO SPREAD
EASTWARD TONIGHT. AIRMASS IS QUITE DRY AND IT WILL TAKE TIME TO
MOISTEN UP THE COLUMN. MODELS CONTINUE TO SHOW MOISTURE DEEPENING
ENOUGH BY 03Z FOR WIDESPREAD UPSLOPE SNOW SHOWERS IN THE WEST.
SREF...NAM AND CANADIAN TAPER MOISTURE/POPS OFF QUICKLY HAS ONE
HEADS WEST. PLAYED THE HIGHEST POPS AND SNOW ACCUMULATIONS IN THE
FAVORED WESTERN UPSLOPE AREAS ESPECIALLY THE GREENBRIER VALLEY. THE
RICHEST MOISTURE WITH THIS SYSTEM WILL PASS TO OUR NORTH. WINDS
ALONG AND BEHIND THE FRONT WILL PICK UP TONIGHT WITH PRESSURE RISES
AND 85H WINDS. STRONGEST 850 GRADIENT ACTUALLY FROM SW RIGHT BEFORE
FRONTAL PASSAGE. STILL LOOK LIKE WE COULD GET SOME ISOLD GUSTS OVER
40 MPH ALONG HIGHEST RIDGES BEHIND THE COLD FRONT IN THE MIDDLE OF
THE NIGHT. CROSS SECTIONS SHOWED POTENTIAL FOR WINDS ABOVE 40 KNOTS
AT THE HIGHEST ELEVATIONS FROM 00-09Z. DECIDED NOT TO POST WIND
ADVISORY AT THIS TIME...WITH VALUES JUST BELOW CRITERIA. WIND CHILLS
WILL ALSO BE CLOSE TO ADVISORY LEVELS OVERNIGHT WITH LIMITED
COVERAGE IN THE HIGHEST ELEVATIONS.
AIR MASS BEHIND ARCTIC FRONT THURSDAY WILL BRING COLDEST
TEMPERATURES OF THE SEASON SO FAR...WITH TEMPERATURES NEARLY STEADY
TO DROPPING DURING THE DAY THURSDAY. GRADIENT GRADUALLY DROPS OFF SO
WINDS WILL BEGIN TO DECREASE THROUGHOUT THE DAY. MOISTURE BECOMES
SHALLOW QUICKLY IN NW UPSLOPE LOCATIONS BUT WITH CYCLONIC FLOW
CONTINUING AND LOW LEVELS COLD ENOUGH TO SUPPORT ICE CRYSTAL GROWTH
THROUGH THE DAY...SOME LIGHT ACCUMULATIONS EXPECTED TO CONTINUE
MAINLY IN WV MTNS. USED SNOW TO LIQUID RATIOS OF 20:1 FOR THIS EVENT
WITH HIGHEST AMOUNTS ARD 4 INCHES POSSIBLE IN NW GREENBRIER.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
ALTHOUGH WIND DIRECTION ISN`T PERFECT...ENOUGH OF AN UPSLOPE
COMPONENT COMBINED WITH MOISTURE AND -20C H85 TEMPS SHOULD BE
SUFFICIENT FOR ACCUMULATING SNOW SHOWERS IN GREENBRIER THURSDAY
NIGHT. AN INCH OR LESS WILL FALL IN THE VALLEYS WITH ANOTHER 1 TO 4
ALONG THE HIGHER ELEVATIONS. A SNOW ADVISORY MAY BE NEEDED.
ALSO...AN UPPER WAVE WILL BE DROPPING THROUGH THE CWA...AND ENOUGH
MOISTURE REMAINS AT H85 FOR SOME SNOW SHOWERS TO PENETRATE THE NEW
RIVER VALLEY. H85 MOISTURE OFF THE NAM HINTS AT ONE OF THESE MORE
LOCALIZED BANDS AFFECTING THE ROA/BCB/PSK CORRIDOR EARLY THURSDAY
NIGHT....WHERE A QUICK INCH OR SO IN A VERY COLD REGIME COULD CAUSE
TRAVEL DIFFICULTIES. NEAR ZERO TO SLIGHTLY NEGATIVE NAM H85-H7 SAT
EPV ALSO PROVIDES SUBTLE HINTS. SNOW SHOWERS WANE AS FRIDAY DAWN
NEARS. MODELS ARE TYPICALLY UNABLE TO FORECAST QPF ON SUCH A SMALL
SCALE...SO WILL CARRY SLT CHC POPS ALTHOUGH NAM/GFS CLAIM DRY. A
WIND CHILL ADVISORY WILL BE NEEDED THURSDAY NIGHT AT LEAST FOR THE
WESTERN HALF OF THE CWA AND WILL CONTINUE TO HIGHLIGHT IN THE HWO.
STRONG HIGH PRESSURE MOVES OVERHEAD FRIDAY NIGHT...AND KEPT MAX T AT
LEAST A FEW DEGREES BELOW GUIDANCE CONSIDERING SHALLOW ARCTIC
AIRMASS. BIG QUESTION IS HOW MANY HIGH CLDS SPILL EAST AND WHEN
FRIDAY NIGHT. IF DELAYED THERE COULD BE WIDESPREAD SUBZERO LOWS WEST
OF THE BLUE RIDGE...ESPECIALLY CONSIDERING THAT THERE WILL BE SOME
SNOW ON THE GROUND ALONG THE LWB/BLF/JFZ CORRIDOR.
AT THE END OF THE SHORT RANGE...MUCH VARIABILITY REMAINS CONCERNING
THE TRACK OF ANOTHER CLIPPER SATURDAY NIGHT INTO SUNDAY. ITS
COMMONPLACE FOR DPROG/DT TO INCH SOUTH WITH EACH RUN WITH SUCH A
DEEP EASTERN TROUGH IN PLACE...ESPECIALLY PRECEDED BY AN ARCTIC
OUTBREAK. ALTHOUGH THE TRACK IS FAR ENOUGH NORTH
CURRENTLY...THERE COULD BE A LIGHT ACCUMULATING SNOW ACROSS THE
NORTHERN HALF OF THE CWA IF THIS CLIPPER ARRIVES FARTHER SOUTH.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
NEXT CLIPPER IN THE EASTERN U.S. TROUGH IS PROGGED TO SWING THROUGH
THE CENTRAL APPALACHIANS SUNDAY. MODELS ARE GRADUALLY SHIFTING THE
TRACK OF THIS CLIPPER A LITTLE FURTHER NORTH...SO I HAVE KEPT THE
POPS FOR THE WARM ADVECTION SNOWS AHEAD OF THE CLIPPER CHANCE...WITH
THE LOWEST ACROSS THE SOUTH. DESPITE WARM ADVECTION SUNDAY...
INCREASED CLOUDS WILL HOLD HIGH TEMPS DOWN IN THE 30S...POSSIBLY
UPPER 20S IN THE MTNS. RENEWED COLD ADVECTION SUNDAY NIGHT ON THE
BACK SIDE OF THE CLIPPER LOOKS COLD...BUT NOWHERE NEAR THE ARCTIC
AIR FROM EARLIER IN THE WEEKEND WITH THE SOURCE REGION EASTERN
CANADA. WILL HAVE MAINLY UPSLOPE SNOW SHOWERS IN THE MTNS SUNDAY
NIGHT.
YET ANOTHER CLIPPER-LIKE SHORT WAVE MAY AFFECT THE AREA MONDAY...BUT
LOOKS TO TRACK A LITTLE FURTHER NORTH. HAVE STAYED CLOSE TO HPC
GUIDANCE FOR THIS ONE...WITH LOW POPS CONFINED TO THE MTNS...HIGHEST
IN SE WV. ONCE AGAIN...MORE COLD ADVECTION MONDAY NIGHT BEHIND THIS
CLIPPER...WITH UPSLOPE SNOW SHOWERS IN THE MTNS.
FINALLY...ANOTHER SHORT WAVE SLIDING DOWN THE TROUGH TUESDAY OR
TUESDAY NIGHT MAY BRING MORE SNOW SHOWERS TO THE MTNS. HAVE STAYED
WITH HPC GUIDANCE WHICH FOLLOWS THE SLOWER ECMWF. THIS BRING A COLD
FRONT THROUGH LATE WEDNESDAY...AND ALLOWS HIGH TEMPS TO WARM QUITE
BIT AHEAD OF THE FNT ON WED.
&&
.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
CHECK AIRMETS AND SIGMETS FOR TURBULENCE...ICING AND MOUNTAIN
OBSCURATIONS THIS AFTERNOON AND TONIGHT. MID AND HIGH LEVEL CLOUDS
SPREADING EAST INTO WESTERN PORTIONS OF CWA THIS AFTERNOON AHEAD OF
LOW PRESSURE IN THE OHIO VALLEY. THIS LOW WILL CROSS QUICKLY THROUGH
THE OHIO VALLEY THIS AFTERNOON AND WILL PUSH A COLD FRONT ACROSS THE
FORECAST AREA THIS EVENING. MVFR CEILINGS WITH MVFR/IFR SNOW SHOWERS
WILL DEVELOP AFTER 06Z BEHIND THE COLD FRONT IN THE MOUNTAINS. WINDS
WILL ALSO INCREASE FROM THE WEST TO NORTHWEST WITH GUSTS FROM 06-12Z
AROUND 40 KNOTS AT HIGHER ELEVATIONS.
DRIER AIR AND VFR CONDITIONS WILL COME IN ON THURSDAY NIGHT AND
FRIDAY ALONG WITH A LARGE HIGH AND ARCTIC AIR. ANOTHER STORM
ARRIVES SATURDAY NIGHT INTO SUNDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...KK/SK
NEAR TERM...AMS/KK
SHORT TERM...KM
LONG TERM...JJ
AVIATION...AMS/KK
000
FXUS61 KRNK 142010
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
310 PM EST WED JAN 14 2009
.SYNOPSIS...
A COLD FRONT WILL TRAVEL EAST ACROSS THE REGION TONIGHT. THIS
FRONT WILL USHER IN THE COLDEST AIR OF THE SEASON SO FAR...ALONG
WITH SOME LIGHT SNOW ACCUMULATIONS ON WESTERN MOUNTAIN
SLOPES...AND GUSTY WINDS WITH DANGEROUS WIND CHILLS AT TIMES.
&&
.NEAR TERM /THROUGH THURSDAY/...
LOW PRESSURE OVER ILLINOIS THIS AFTERNOON WILL MOVE EAST TONIGHT AND
PUSHES A COLD FRONT THROUGH THE COUNTY WARNING AREA. CLOUD COVER AND
MOISTURE ASSOCIATED WITH THIS SYSTEM WILL CONTINUE TO SPREAD
EASTWARD TONIGHT. AIRMASS IS QUITE DRY AND IT WILL TAKE TIME TO
MOISTEN UP THE COLUMN. MODELS CONTINUE TO SHOW MOISTURE DEEPENING
ENOUGH BY 03Z FOR WIDESPREAD UPSLOPE SNOW SHOWERS IN THE WEST.
SREF...NAM AND CANADIAN TAPER MOISTURE/POPS OFF QUICKLY HAS ONE
HEADS WEST. PLAYED THE HIGHEST POPS AND SNOW ACCUMULATIONS IN THE
FAVORED WESTERN UPSLOPE AREAS ESPECIALLY THE GREENBRIER VALLEY. THE
RICHEST MOISTURE WITH THIS SYSTEM WILL PASS TO OUR NORTH. WINDS
ALONG AND BEHIND THE FRONT WILL PICK UP TONIGHT WITH PRESSURE RISES
AND 85H WINDS. STRONGEST 850 GRADIENT ACTUALLY FROM SW RIGHT BEFORE
FRONTAL PASSAGE. STILL LOOK LIKE WE COULD GET SOME ISOLD GUSTS OVER
40 MPH ALONG HIGHEST RIDGES BEHIND THE COLD FRONT IN THE MIDDLE OF
THE NIGHT. CROSS SECTIONS SHOWED POTENTIAL FOR WINDS ABOVE 40 KNOTS
AT THE HIGHEST ELEVATIONS FROM 00-09Z. DECIDED NOT TO POST WIND
ADVISORY AT THIS TIME...WITH VALUES JUST BELOW CRITERIA. WIND CHILLS
WILL ALSO BE CLOSE TO ADVISORY LEVELS OVERNIGHT WITH LIMITED
COVERAGE IN THE HIGHEST ELEVATIONS.
AIR MASS BEHIND ARCTIC FRONT THURSDAY WILL BRING COLDEST
TEMPERATURES OF THE SEASON SO FAR...WITH TEMPERATURES NEARLY STEADY
TO DROPPING DURING THE DAY THURSDAY. GRADIENT GRADUALLY DROPS OFF SO
WINDS WILL BEGIN TO DECREASE THROUGHOUT THE DAY. MOISTURE BECOMES
SHALLOW QUICKLY IN NW UPSLOPE LOCATIONS BUT WITH CYCLONIC FLOW
CONTINUING AND LOW LEVELS COLD ENOUGH TO SUPPORT ICE CRYSTAL GROWTH
THROUGH THE DAY...SOME LIGHT ACCUMULATIONS EXPECTED TO CONTINUE
MAINLY IN WV MTNS. USED SNOW TO LIQUID RATIOS OF 20:1 FOR THIS EVENT
WITH HIGHEST AMOUNTS ARD 4 INCHES POSSIBLE IN NW GREENBRIER.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
AIR MASS BEHIND ARCTIC FRONT WILL BRING COLDEST TEMPERATURES OF
THE SEASON SO FAR...WITH TEMPERATURES STEADY TO DROPPING DURING THE DAY
THURS. GRADIENT GRADUALLY DROPS OFF SO WINDS WILL BEGIN TO
DECREASE THROUGHOUT THE DAY...BUT WILL STILL RESULT IN WIND
CHILLS IN THE SINGLE DIGITS WEST...TO 20S IN THE EAST...AND THIS
DURING THE DAYTIME. MOISTURE BECOMES SHALLOW QUICKLY IN NW
UPSLOPE LOCATIONS BUT WITH CYCLONIC FLOW CONTINUING AND LOW LEVELS
COLD ENOUGH TO SUPPORT ICE CRYSTAL GROWTH THROUGH THE DAY...SOME
LIGHT ACCUMULATIONS EXPECTED TO CONTINUE MAINLY IN WV MTNS. USED
SNOW TO LIQUID RATIOS OF 20:1 OR HIGHER...RESULTING IN ANOTHER 1-3
INCHES IN FAVORED AREAS DURING THE DAY.
ANOTHER WEAKER WAVE FCST TO SWING THROUGH BY THURS EVENING...
PERHAPS KEEPING SOME SNOW SHWRS GOING ON WESTERN SLOPES...AND ALSO
TEMPORARILY INCREASING GRADIENT OVERNIGHT...SO AS TEMPS REALLY
PLUMMET WITH COLDEST LOW LEVEL THICKNESSES...WIND CHILLS WILL BE
AT THEIR COLDEST OVERNIGHT THURSDAY AND INTO FRIDAY. DID NOT MAKE
ANY SIGNIFICANT CHANGES TO TEMPS...ALTHOUGH MODERATED HIGHS
SLIGHTLY FOR FRI AND SAT PER GUIDANCE TRENDS...BUT DID INCREASE
WINDS THURS NIGHT AND INTO FRIDAY. THIS RESULTED IN COLDER WIND
CHILLS..WITH MANY LOCATIONS IN WEST MINUS 5 TO MINUS 10 THROUGH AT
LEAST MIDDAY FRIDAY. WILL CONTINUE TO HIGHLIGHT THIS IN THE
HAZARDOUS WEATHER OUTLOOK...BUT STILL TOO FAR OUT TO ISSUE THE
WIND CHILL ADVISORY. IT IS LOOKING MORE AND MORE LIKELY THAT IT
WILL EVENTUALLY BE NEEDED.
LOWS SATURDAY MORNING TRICKY AS HIGH SETTLES OVERHEAD SOME AREAS
WILL SEE EXCELLENT RADIATIONAL COOLING..BUT TRENDS ARE TO BRING
NEXT WAVE IN A LITTLE QUICKER...AND POSSIBLE SW WINDS AND WARM ADV
WITH HIGHER CLOUDS INTO THE WEST BEFORE DAWN...SO THIS WOULD LIMIT
HOW LOW TEMPS COULD GET IN AT LEAST PART OF THE REGION. TIMING OF
THIS COULD CHANGE THOUGH...SO MADE NO SIGNIFICANT CHANGES HERE
EITHER...OTHER THAN THE SLIGHT MODERATION OF HIGHS ON SATURDAY PER
LATEST GUIDANCE TRENDS AS WARM ADV LOOKS LIKE IT COULD BE STRONGER
THAN EARLIER THOUGHT. STILL...TEMPERATURES WAY BELOW NORMAL FOR
SATURDAY AND LIKELY NOT REACHING FREEZING AGAIN IN THE MOUNTAINS.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
NEXT CLIPPER IN THE EASTERN U.S. TROUGH IS PROGGED TO SWING THROUGH
THE CENTRAL APPALACHIANS SUNDAY. MODELS ARE GRADUALLY SHIFTING THE
TRACK OF THIS CLIPPER A LITTLE FURTHER NORTH...SO I HAVE KEPT THE
POPS FOR THE WARM ADVECTION SNOWS AHEAD OF THE CLIPPER CHANCE...WITH
THE LOWEST ACROSS THE SOUTH. DESPITE WARM ADVECTION SUNDAY...
INCREASED CLOUDS WILL HOLD HIGH TEMPS DOWN IN THE 30S...POSSIBLY
UPPER 20S IN THE MTNS. RENEWED COLD ADVECTION SUNDAY NIGHT ON THE
BACK SIDE OF THE CLIPPER LOOKS COLD...BUT NOWHERE NEAR THE ARCTIC
AIR FROM EARLIER IN THE WEEKEND WITH THE SOURCE REGION EASTERN
CANADA. WILL HAVE MAINLY UPSLOPE SNOW SHOWERS IN THE MTNS SUNDAY
NIGHT.
YET ANOTHER CLIPPER-LIKE SHORT WAVE MAY AFFECT THE AREA MONDAY...BUT
LOOKS TO TRACK A LITTLE FURTHER NORTH. HAVE STAYED CLOSE TO HPC
GUIDANCE FOR THIS ONE...WITH LOW POPS CONFINED TO THE MTNS...HIGHEST
IN SE WV. ONCE AGAIN...MORE COLD ADVECTION MONDAY NIGHT BEHIND THIS
CLIPPER...WITH UPSLOPE SNOW SHOWERS IN THE MTNS.
FINALLY...ANOTHER SHORT WAVE SLIDING DOWN THE TROUGH TUESDAY OR
TUESDAY NIGHT MAY BRING MORE SNOW SHOWERS TO THE MTNS. HAVE STAYED
WITH HPC GUIDANCE WHICH FOLLOWS THE SLOWER ECMWF. THIS BRING A COLD
FRONT THROUGH LATE WEDNESDAY...AND ALLOWS HIGH TEMPS TO WARM QUITE
BIT AHEAD OF THE FNT ON WED.
&&
.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
CHECK AIRMETS AND SIGMETS FOR TURBULENCE...ICING AND MOUNTAIN
OBSCURATIONS THIS AFTERNOON AND TONIGHT. MID AND HIGH LEVEL CLOUDS
SPREADING EAST INTO WESTERN PORTIONS OF CWA THIS AFTERNOON AHEAD OF
LOW PRESSURE IN THE OHIO VALLEY. THIS LOW WILL CROSS QUICKLY THROUGH
THE OHIO VALLEY THIS AFTERNOON AND WILL PUSH A COLD FRONT ACROSS THE
FORECAST AREA THIS EVENING. MVFR CEILINGS WITH MVFR/IFR SNOW SHOWERS
WILL DEVELOP AFTER 06Z BEHIND THE COLD FRONT IN THE MOUNTAINS. WINDS
WILL ALSO INCREASE FROM THE WEST TO NORTHWEST WITH GUSTS FROM 06-12Z
AROUND 40 KNOTS AT HIGHER ELEVATIONS.
DRIER AIR AND VFR CONDITIONS WILL COME IN ON THURSDAY NIGHT AND
FRIDAY ALONG WITH A LARGE HIGH AND ARCTIC AIR. ANOTHER STORM
ARRIVES SATURDAY NIGHT INTO SUNDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...KK/SK
NEAR TERM...AMS/KK
SHORT TERM...SK
LONG TERM...JJ
AVIATION...AMS/KK
000
FXUS61 KLWX 141959
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
241 PM EST WED JAN 14 2009
.SYNOPSIS...
AN ALBERTA CLIPPER AND ITS ASSOCIATED COLD FRONT WILL PASS THROUGH
TONIGHT INTO EARLY THURSDAY. BITTERLY COLD CONDITIONS ARE EXPECTED
BEHIND THIS SYSTEM THROUGH THE FIRST PART OF THE WEEKEND. ANOTHER
SYSTEM MAY AFFECT THE REGION LATER THIS WEEKEND INTO EARLY NEXT
WEEK. HIGH PRESSURE WILL BRING DRY AND CHILLY CONDITIONS BY THE
MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
MID TO HIGH CLOUDS HAVE BEEN INCREASING AND THICKENING THROUGH THE
AFTERNOON AHEAD OF LOW PRESSURE OVER THE OHIO VALLEY. SNOW HAS
PROGRESSES AS FAR EAST AS PITTSBURGH AT 2 AM.
MODELS ARE IN GOOD AGREEMENT WITH THE CLIPPER SYSTEM MOVING EAST
ACROSS THE NORTHERN PORTION OF THE CWA /NEARLY ALONG HIGHWAY 50/
TONIGHT. SNOW WILL MOVE INTO THE ALLEGHENY HIGHLANDS EARLY THIS
EVENING...AND THEN ATTEMPT TO SPREAD FURTHER EAST LATER THIS
EVENING. ONE OF THE PUZZLING ASPECTS OF THIS SYSTEM IS THAT THE
MODELS AND SREF SIGNIFICANTLY DWINDLE PRECIPITATION EAST OF THE MTNS
THIS EVENING. A GOOD CHUNK LIKELY WILL GET SHUNTED NORTH INTO
PENNSYLVANIA...BUT BELIEVE THIS IS ONE OF THOSE SYSTEMS THAT WILL BE
ABLE TO SUSTAIN SOME LIGHT PRECIPITATION EAST OF THE MTNS.
PRECIPITATION WILL BE IN THE FORM OF SNOW. HIGHEST TOTALS WILL OCCUR
IN THE ALLEGHENY HIGHLANDS WHERE LOW PRESSURE ITSELF AND THEN
UPSLOPE ENHANCED SNOW BEHIND THE SYSTEM CONTRIBUTE TO SNOWFALL
TOTALS /2 TO 4 INCHES/. THINK THAT ACCUMULATING SNOW WILL BE ABLE TO
MAKE IT EAST OF THE ALLEGHENY FRONT AND HAVE WINTER WEATHER ADVISORY
EXTENDING INTO THE EASTERN SECTIONS OF ALLEGANY...MINERAL AND GRANT
/1 TO 2 INCHES/. EVEN FURTHER EAST INTO HGR/MRB...SOME LIGHT
ACCUMULATION IS POSSIBLE BUT IT LOOKS TO BE A HALF INCH OR LESS
ATTM. LITTLE OR NO SNOW ACCUMULATION IS EXPECTED ALONG THE BALTIMORE
WASHINGTON METRO CORRIDOR WHERE 20 TO 30 POPS WILL BE PLACED.
&&
.SHORT TERM /THURSDAY/...
CLIPPER AND ASSOCIATED ARCTIC FRONT WILL MOVE EAST OF THE BAY BY
10Z. ANY LINGERING PRECIPITATION WILL GENERALLY BE RELEGATED TO WEST
OF THE BLUE RIDGE ESPECIALLY UPSLOPE LOCATIONS...ALTHOUGH CANT RULE
OUT A FEW FLURRIES IN THE MORNING ACROSS THE BALTIMORE WASHINGTON
METRO AREA.
NORTHWEST WINDS WILL DRAG IN COLDER AIR INTO THE REGION. WIND CHILL
VALUES WILL BE 5 BELOW OR LESS ACROSS THE HIGHLANDS AND A WIND CHILL
ADVISORY WILL BE IN EFFECT THROUGH THURSDAY AFTERNOON WITH THE
REALIZATION THAT IT WILL LIKELY NEED TO BE EXTENDED TEMPORALLY AND
EXPANDED GEOGRAPHICALLY.
GIVEN NORTHWEST FLOW...WENT A COUPLE DEGREES BELOW MOS FOR MAX T.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
ARCTIC HIGH PRESSURE WILL BUILD OVER THE REGION FOR THE END OF THE
WEEK BRINGING DRY BUT BITTERLY COLD CONDITIONS. TEMPERATURES WILL
AVERAGE 20-25 DEGREES BELOW CLIMO. HAVE WENT BELOW GUIDANCE DURING
THIS TIME WITH THE COLDEST TEMPERATURES PREDICTED FRIDAY NIGHT. MIN
TEMPS FRIDAY NIGHT WILL RANGE FROM BELOW ZERO IN THE POTOMAC
HIGHLANDS TO THE SINGLE DIGITS ACROSS THE WASHINGTON AND BALTIMORE
METROPOLITAN AREAS. AM CONCERNED IT COULD EVEN BE A FEW DEGREES
COLDER GIVEN THE FACT THAT DEWPOINTS ARE PROGGED TO BE BELOW ZERO
FRIDAY NIGHT WITH THE SURFACE HIGH OVERHEAD.
HIGH PRESSURE WILL MOVE OFF THE COAST SATURDAY AND THE NEXT CLIPPER
WILL PASS THROUGH THE REGION LATE IN THE WEEKEND INTO EARLY NEXT
WEEK. SUBTLE DIFFERENCES IN THE UPPER AIR PATTERN AMONG THE LONG
RANGE GUIDANCE HAS LED TO UNCERTAINTY IN TIMING FOR ANY
PRECIPITATION THAT WOULD DEVELOP FROM THIS CLIPPER. FOR NOW...WENT
WITH THE HIGHEST POPS SATURDAY NIGHT AND SUNDAY WHICH IS CLOSER TO
THE 00Z ECMWF SOLUTION RATHER THAN THE GFS WHICH HAS HIGHER POPS
SUNDAY NIGHT AND MONDAY.
LATEST GUIDANCE CONTINUES TO KEEP THE TROUGH OF LOW PRESSURE OVER
THE REGION TUESDAY AND WEDNESDAY BRINGING BELOW NORMAL TEMPERATURES.
THERE MAY BE ENOUGH COLD AIR ALOFT FOR SNOW SHOWERS TUESDAY. WILL
CONTINUE WITH THE SLIGHT CHANCE OF SNOW SHOWERS FOR NOW.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
VFR CONDITIONS THIS AFTERNOON AND EVENING WITH WLY WINDS 5-10 KT AND
BKN TO OVC 10 KFT CIGS. WINDS TO SHIFT SLY (AROUND 5 KT) OVERNIGHT
IN ADVANCE OF A SFC LOW AND COLD FRONT THAT THAT WILL CROSS THE
REGION BETWEEN EARLY TO MID MORNING HOURS THURSDAY. INCLUDED LIGHT
SNOW SHOWERS WITH MVFR CIGS AT KMRB AHEAD OF THE LOW FROM 03Z TO
10Z. SLIGHT CHANCE OF SNOW SHOWERS/FLURRIES ACROSS THE REST OF THE
TAF SITES THRU THE DAY THURSDAY...THOUGH CHANCES DECREASE AFTER
FROPA. EXPECT GUSTY W/W-NWLY WINDS THURSDAY WITH THE HIGHEST GUSTS
(25 TO 30 KT) DURING AND JUST AFTER FROPA (TIMING 10Z TO 12Z ACROSS
TAF SITES)...NW WINDS WITH 20 TO 25 KT GUSTS REST OF THURSDAY.
HIGH PRESSURE WILL BRING VFR CONDITIONS THURSDAY NIGHT THROUGH
SATURDAY. AN ALBERTA CLIPPER WILL PASS THROUGH THE TERMINALS LATE IN
THE WEEKEND INTO EARLY NEXT WEEK BRINGING THE NEXT CHANCE FOR
PRECIPITATION.
&&
.MARINE...
CLIPPER LOW AND ARCTIC FRONT MOVE ACROSS THE WATERS EARLY THURSDAY
MORNING. SOUTHERLY FLOW AHEAD OF THE SYSTEM WILL INCREASE INTO SMALL
CRAFT ADVISORY CRITERIA AROUND MIDNIGHT /20 TO 25 KT/. A WIND SHIFT
TO THE WEST NORTHWEST WILL OCCUR AS THE SYSTEM PASSES THROUGH WITH
GUSTS UP TO 30 KT. THERE IS A SMALL POTENTIAL OF BRIEF 35 KT GUSTS
BUT CONFIDENCE IS NOT HIGH ENOUGH AT THIS TIME TO ISSUE A GALE
WARNING. THEREFORE...SMALL CRAFT ADVISORY WILL BE IN EFFECT THROUGH
THURSDAY.
HIGH PRESSURE WILL APPROACH THE WATERS THURSDAY NIGHT...BUT THERE
WILL BE ENOUGH OF A PRESSURE GRADIENT FOR WEST-NORTHWEST WINDS OVER
20 KNOTS. HAVE ISSUED A SMALL CRAFT ADVISORY THURSDAY NIGHT.
HIGH PRESSURE WILL BUILD OVER THE WATERS FRIDAY INTO SATURDAY. THE
NEXT CLIPPER MAY PASS THROUGH THE WATERS LATE IN THE WEEKEND INTO
EARLY NEXT WEEK BRINGING A CHANCE FOR PRECIPITATION.
&&
.CLIMATE...
VERY COLD WEATHER IS STILL EXPECTED THIS FRIDAY /16 JAN/ INTO
SATURDAY MORNING /17 JAN/. HOWEVER...SINCE THIS IS NEAR THE
CLIMATOLOGICALLY COLDEST TIME OF YEAR...RECORD LOWS AND/OR RECORD
LOW MAXIMUM TEMPERATURES ARE UNLIKELY IN THE BALTIMORE/WASHINGTON
METROPOLITAN AREA. DESPITE GUIDANCE SUGGESTING SLIGHTLY HIGHER
TEMPERATURES ON SATURDAY MORNING...IT STILL DOES LOOK TO BE SOME OF
THE COLDEST AIR IN THE PAST 15 YEARS. PLEASE NOTE THAT IT WAS
SIGNIFICANTLY COLDER DURING A COLD SPELL IN MID JANUARY 1994 AT
BWI/DCA/IAD.
BELOW ARE THE LATEST FORECAST MAXIMA FOR FRIDAY AND MINIMA FOR
SATURDAY AT BWI/DCA/IAD WITH RECENT TIMES TEMPERATURES NEARED THESE
VALUES...AS WELL AS RECORD LOWEST MAX ON 16 JAN AND RECORD LOW ON 17
JAN.
BWI...FRI FCST HIGH: 20 F /HIGH OF 19 F ON JAN 10 2004 AND FEB 4
1996 AND 20 ON FEB 5 2007...RECORD LOW MAXIMUM OF 14 F IN 1893/
DCA...FRI FCST HIGH: 20 F /HIGH OF 17 F ON FEB 4 1996 AND 20 F ON
FEB 3 1996 AND 21 F ON JAN 10 2004...RECORD LOW MAXIMUM OF 15 F IN
1893/
IAD...FRI FCST HIGH: 19 F /HIGH OF 14 F ON FEB 4 1996 AND 19 F ON
JAN 17-18 1997 AND 20 ON FEB 5 2007...RECORD LOW MAXIMUM OF 14 IN
1972 AND 1996/
BWI...SAT FCST LOW: 5 F /LOW OF 1 ON JAN 19 1997 AND 4 ON FEB 6 1996
AND 5 ON JAN 18 2003...RECORD LOW OF -7 IN 1982/
DCA...SAT FCST LOW: 9 F /LOW OF 8 F ON JAN 10 2004 AND 9 ON FEB 4
1996...RECORD LOW OF -5 IN 1982/
IAD...SAT FCST LOW: 3 F /LOW OF 1 F ON DEC 7 2002 AND 3 ON JAN 29
2004...RECORD LOW OF -7 IN 1982/
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 12 PM EST
THURSDAY FOR MDZ501-502.
WIND CHILL ADVISORY FROM 4 AM TO 6 PM EST THURSDAY FOR MDZ501-
502.
VA...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 12 PM EST
THURSDAY FOR VAZ021.
WIND CHILL ADVISORY FROM 4 AM TO 6 PM EST THURSDAY FOR VAZ021.
WV...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 12 PM EST
THURSDAY FOR WVZ054-501>504.
WIND CHILL ADVISORY FROM 4 AM TO 6 PM EST THURSDAY FOR WVZ054-
501>504.
MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM EST
FRIDAY FOR ANZ530>537.
&&
$$
SYNOPSIS...PELOQUIN/BJL
NEAR TERM...PELOQUIN
SHORT TERM...PELOQUIN
LONG TERM...BJL
AVIATION...BAJ/BJL
MARINE...PELOQUIN/BJL
CLIMATE...BAJ/JRK/MRK
000
FXUS61 KLWX 141941
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
241 PM EST WED JAN 14 2009
.SYNOPSIS...
AN ALBERTA CLIPPER AND ITS ASSOCIATED COLD FRONT WILL PASS THROUGH
TONIGHT INTO EARLY THURSDAY. BITTERLY COLD CONDITIONS ARE EXPECTED
BEHIND THIS SYSTEM THROUGH THE FIRST PART OF THE WEEKEND. ANOTHER
SYSTEM MAY AFFECT THE REGION LATER THIS WEEKEND INTO EARLY NEXT
WEEK. HIGH PRESSURE WILL BRING DRY AND CHILLY CONDITIONS BY THE
MIDDLE OF NEXT WEEK.
&&
.NEAR TERM /THROUGH TONIGHT/...
MID TO HIGH CLOUDS HAVE BEEN INCREASING AND THICKENING THROUGH THE
AFTERNOON AHEAD OF LOW PRESSURE OVER THE OHIO VALLEY. SNOW HAS
PROGRESSES AS FAR EAST AS PITTSBURGH AT 2 AM.
MODELS ARE IN GOOD AGREEMENT WITH THE CLIPPER SYSTEM MOVING EAST
ACROSS THE NORTHERN PORTION OF THE CWA /NEARLY ALONG HIGHWAY 50/
TONIGHT. SNOW WILL MOVE INTO THE ALLEGHENY HIGHLANDS EARLY THIS
EVENING...AND THEN ATTEMPT TO SPREAD FURTHER EAST LATER THIS
EVENING. ONE OF THE PUZZLING ASPECTS OF THIS SYSTEM IS THAT THE
MODELS AND SREF SIGNIFICANTLY DWINDLE PRECIPITATION EAST OF THE MTNS
THIS EVENING. A GOOD CHUNK LIKELY WILL GET SHUNTED NORTH INTO
PENNSYLVANIA...BUT BELIEVE THIS IS ONE OF THOSE SYSTEMS THAT WILL BE
ABLE TO SUSTAIN SOME LIGHT PRECIPITATION EAST OF THE MTNS.
PRECIPITATION WILL BE IN THE FORM OF SNOW. HIGHEST TOTALS WILL OCCUR
IN THE ALLEGHENY HIGHLANDS WHERE LOW PRESSURE ITSELF AND THEN
UPSLOPE ENHANCED SNOW BEHIND THE SYSTEM CONTRIBUTE TO SNOWFALL
TOTALS /2 TO 4 INCHES/. THINK THAT ACCUMULATING SNOW WILL BE ABLE TO
MAKE IT EAST OF THE ALLEGHENY FRONT AND HAVE WINTER WEATHER ADVISORY
EXTENDING INTO THE EASTERN SECTIONS OF ALLEGANY...MINERAL AND GRANT
/1 TO 2 INCHES/. EVEN FURTHER EAST INTO HGR/MRB...SOME LIGHT
ACCUMULATION IS POSSIBLE BUT IT LOOKS TO BE A HALF INCH OR LESS
ATTM. LITTLE OR NO SNOW ACCUMULATION IS EXPECTED ALONG THE BALTIMORE
WASHINGTON METRO CORRIDOR WHERE 20 TO 30 POPS WILL BE PLACED.
&&
.SHORT TERM /THURSDAY/...
CLIPPER AND ASSOCIATED ARCTIC FRONT WILL MOVE EAST OF THE BAY BY
10Z. ANY LINGERING PRECIPITATION WILL GENERALLY BE RELEGATED TO WEST
OF THE BLUE RIDGE ESPECIALLY UPSLOPE LOCATIONS...ALTHOUGH CANT RULE
OUT A FEW FLURRIES IN THE MORNING ACROSS THE BALTIMORE WASHINGTON
METRO AREA.
NORTHWEST WINDS WILL DRAG IN COLDER AIR INTO THE REGION. WIND CHILL
VALUES WILL BE 5 BELOW OR LESS ACROSS THE HIGHLANDS AND A WIND CHILL
ADVISORY WILL BE IN EFFECT THROUGH THURSDAY AFTERNOON WITH THE
REALIZATION THAT IT WILL LIKELY NEED TO BE EXTENDED TEMPORALLY AND
EXPANDED GEOGRAPHICALLY.
GIVEN NORTHWEST FLOW...WENT A COUPLE DEGREES BELOW MOS FOR MAX T.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
ARCTIC HIGH PRESSURE WILL BUILD OVER THE REGION FOR THE END OF THE
WEEK BRINGING DRY BUT BITTERLY COLD CONDITIONS. TEMPERATURES WILL
AVERAGE 20-25 DEGREES BELOW CLIMO. HAVE WENT BELOW GUIDANCE DURING
THIS TIME WITH THE COLDEST TEMPERATURES PREDICTED FRIDAY NIGHT. MIN
TEMPS FRIDAY NIGHT WILL RANGE FROM BELOW ZERO IN THE POTOMAC
HIGHLANDS TO THE SINGLE DIGITS ACROSS THE WASHINGTON AND BALTIMORE
METROPOLITAN AREAS. AM CONCERNED IT COULD EVEN BE A FEW DEGREES
COLDER GIVEN THE FACT THAT DEWPOINTS ARE PROGGED TO BE BELOW ZERO
FRIDAY NIGHT WITH THE SURFACE HIGH OVERHEAD.
HIGH PRESSURE WILL MOVE OFF THE COAST SATURDAY AND THE NEXT CLIPPER
WILL PASS THROUGH THE REGION LATE IN THE WEEKEND INTO EARLY NEXT
WEEK. SUBTLE DIFFERENCES IN THE UPPER AIR PATTERN AMONG THE LONG
RANGE GUIDANCE HAS LED TO UNCERTAINTY IN TIMING FOR ANY
PRECIPITATION THAT WOULD DEVELOP FROM THIS CLIPPER. FOR NOW...WENT
WITH THE HIGHEST POPS SATURDAY NIGHT AND SUNDAY WHICH IS CLOSER TO
THE 00Z ECMWF SOLUTION RATHER THAN THE GFS WHICH HAS HIGHER POPS
SUNDAY NIGHT AND MONDAY.
LATEST GUIDANCE CONTINUES TO KEEP THE TROUGH OF LOW PRESSURE OVER
THE REGION TUESDAY AND WEDNESDAY BRINGING BELOW NORMAL TEMPERATURES.
THERE MAY BE ENOUGH COLD AIR ALOFT FOR SNOW SHOWERS TUESDAY. WILL
CONTINUE WITH THE SLIGHT CHANCE OF SNOW SHOWERS FOR NOW.
&&
.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
VFR CONDITIONS THIS AFTERNOON AND EVENING WITH WLY WINDS 5-10 KT AND
BKN TO OVC 10 KFT CIGS. WINDS TO SHIFT SLY (AROUND 5 KT) OVERNIGHT
IN ADVANCE OF A SFC LOW AND COLD FRONT THAT THAT WILL CROSS THE
REGION BETWEEN EARLY TO MID MORNING HOURS THURSDAY. INCLUDED LIGHT
SNOW SHOWERS WITH MVFR CIGS AT KMRB AHEAD OF THE LOW FROM 03Z TO
10Z. SLIGHT CHANCE OF SNOW SHOWERS/FLURRIES ACROSS THE REST OF THE
TAF SITES THRU THE DAY THURSDAY...THOUGH CHANCES DECREASE AFTER
FROPA. EXPECT GUSTY W/W-NWLY WINDS THURSDAY WITH THE HIGHEST GUSTS
(25 TO 30 KT) DURING AND JUST AFTER FROPA (TIMING 10Z TO 12Z ACROSS
TAF SITES)...NW WINDS WITH 20 TO 25 KT GUSTS REST OF THURSDAY.
HIGH PRESSURE WILL BRING VFR CONDITIONS THURSDAY NIGHT THROUGH
SATURDAY. AN ALBERTA CLIPPER WILL PASS THROUGH THE TERMINALS LATE IN
THE WEEKEND INTO EARLY NEXT WEEK BRINGING THE NEXT CHANCE FOR
PRECIPITATION.
&&
.MARINE...
CLIPPER LOW AND ARCTIC FRONT MOVE ACROSS THE WATERS EARLY THURSDAY
MORNING. SOUTHERLY FLOW AHEAD OF THE SYSTEM WILL INCREASE INTO SMALL
CRAFT ADVISORY CRITERIA AROUND MIDNIGHT /20 TO 25 KT/. A WIND SHIFT
TO THE WEST NORTHWEST WILL OCCUR AS THE SYSTEM PASSES THROUGH WITH
GUSTS UP TO 30 KT. THERE IS A SMALL POTENTIAL OF BRIEF 35 KT GUSTS
BUT CONFIDENCE IS NOT HIGH ENOUGH AT THIS TIME TO ISSUE A GALE
WARNING. THEREFORE...SMALL CRAFT ADVISORY WILL BE IN EFFECT THROUGH
THURSDAY.
HIGH PRESSURE WILL APPROACH THE WATERS THURSDAY NIGHT...BUT THERE
WILL BE ENOUGH OF A PRESSURE GRADIENT FOR WEST-NORTHWEST WINDS OVER
20 KNOTS. HAVE ISSUED A SMALL CRAFT ADVISORY THURSDAY NIGHT.
HIGH PRESSURE WILL BUILD OVER THE WATERS FRIDAY INTO SATURDAY. THE
NEXT CLIPPER MAY PASS THROUGH THE WATERS LATE IN THE WEEKEND INTO
EARLY NEXT WEEK BRINGING A CHANCE FOR PRECIPITATION.
&&
.CLIMATE...
VERY COLD WEATHER IS STILL EXPECTED THIS FRIDAY /16 JAN/ INTO
SATURDAY MORNING /17 JAN/. HOWEVER...SINCE THIS IS NEAR THE
CLIMATOLOGICALLY COLDEST TIME OF YEAR...RECORD LOWS AND/OR RECORD
LOW MAXIMUM TEMPERATURES ARE UNLIKELY IN THE BALTIMORE/WASHINGTON
METROPOLITAN AREA. DESPITE GUIDANCE SUGGESTING SLIGHTLY HIGHER
TEMPERATURES ON SATURDAY MORNING...IT STILL DOES LOOK TO BE SOME OF
THE COLDEST AIR IN THE PAST 15 YEARS. PLEASE NOTE THAT IT WAS
SIGNIFICANTLY COLDER DURING A COLD SPELL IN MID JANUARY 1994 AT
BWI/DCA/IAD.
BELOW ARE THE LATEST FORECAST MAXIMA FOR FRIDAY AND MINIMA FOR
SATURDAY AT BWI/DCA/IAD WITH RECENT TIMES TEMPERATURES NEARED THESE
VALUES...AS WELL AS RECORD LOWEST MAX ON 16 JAN AND RECORD LOW ON 17
JAN.
BWI...FRI FCST HIGH: 20 F /HIGH OF 19 F ON JAN 10 2004 AND FEB 4
1996 AND 20 ON FEB 5 2007...RECORD LOW MAXIMUM OF 14 F IN 1893/
DCA...FRI FCST HIGH: 20 F /HIGH OF 17 F ON FEB 4 1996 AND 20 F ON
FEB 3 1996 AND 21 F ON JAN 10 2004...RECORD LOW MAXIMUM OF 15 F IN
1893/
IAD...FRI FCST HIGH: 19 F /HIGH OF 14 F ON FEB 4 1996 AND 19 F ON
JAN 17-18 1997 AND 20 ON FEB 5 2007...RECORD LOW MAXIMUM OF 14 IN
1972 AND 1996/
BWI...SAT FCST LOW: 5 F /LOW OF 1 ON JAN 19 1997 AND 4 ON FEB 6 1996
AND 5 ON JAN 18 2003...RECORD LOW OF -7 IN 1982/
DCA...SAT FCST LOW: 9 F /LOW OF 8 F ON JAN 10 2004 AND 9 ON FEB 4
1996...RECORD LOW OF -5 IN 1982/
IAD...SAT FCST LOW: 3 F /LOW OF 1 F ON DEC 7 2002 AND 3 ON JAN 29
2004...RECORD LOW OF -7 IN 1982/
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 12 PM EST
THURSDAY FOR MDZ501-502.
WIND CHILL ADVISORY FROM 4 AM TO 6 PM EST THURSDAY FOR MDZ501-
502.
VA...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 12 PM EST
THURSDAY FOR VAZ021.
WIND CHILL ADVISORY FROM 4 AM TO 6 PM EST THURSDAY FOR VAZ021.
WV...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 12 PM EST
THURSDAY FOR WVZ054-501>504.
WIND CHILL ADVISORY FROM 4 AM TO 6 PM EST THURSDAY FOR WVZ054-
501>504.
MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 10 PM EST
THURSDAY FOR ANZ530>537.
&&
$$
SYNOPSIS...PELOQUIN/BJL
NEAR TERM...PELOQUIN
SHORT TERM...PELOQUIN
LONG TERM...BJL
AVIATION...BAJ/BJL
MARINE...PELOQUIN/BJL
CLIMATE...BAJ/JRK/MRK
000
FXUS61 KAKQ 141816
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
116 PM EST WED JAN 14 2009
.SYNOPSIS...
HIGH PRESSURE BRIEFLY BUILDS INTO THE MID ATLANTIC REGION FROM
THE SOUTHWEST TODAY. A STRONG COLD FRONT CROSSES THE REGION
THURSDAY...FOLLOWED BY ARCTIC HIGH PRESSURE AND VERY COLD AIR FOR
THURSDAY NIGHT INTO SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE 1ST PHASE OF THE ARCTIC INVASION TAKES PLC TDA. GSTY NNW WNDS
USHERING IN COLDER/DRY AMS ATTM...WNDSPDS STAY UP THROUGH THE MRNG
HRS B4 DCRSG AS WK SFC HI PRES NOSES INTO RGN FM THE SW. ALREADY
WL BE LOOKING WWD FOR NEXT CLIPPER SYS APPROACHING FM THE NW WHICH
SPRDS SCT/BKN CLDNS INTO FA BY LT AFTN HRS. HI TEMPS FM THE L30S
TO L40S...W/ DWPTS DROPPING INTO THE SINGLE DIGITS/TEENS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
LLVL FLO SWINGS TO SW...AND INCRSS OVRNGT. AFT QUIK TEMP DROP
(ERY) THIS EVE...RDGS LVL OFF FOR THE REST OF THE NGT. SFC LO PRES
TRACKS BY JUST N OF RGN...W/ TRAILING (STRNG) CDFNT TO THE CST BY
12Z/15. STRNG LLVL CAA TO FOLLOW DURG THU...TEMPS NOT LIKELY TO
RISE TO MUCH FM MRNG RDGS (HI TEMPS MNLY M30S TO M40S). ANOTHER
RND OF GSTY NNW WNDS (LT TNGT/THU)...RESULTS IN WND CHILLS IN THE
TEENS/20S.
MUCH COLDER/XTRMLY DRY THU NGT/FRI...UNDER GENLY SKC. DWPTS MSTLY
FM 5 BLO ZERO TO 5 ABV ZERO. LO TEMPS THU NGT IN THE TEENS TO
L20S...HI TEMPS FRI STRUGGLE TO REACH THE U20S/ARND 30 DESPITE
SUNSHINE.
CNTR OF ARCTIC SFC HI PRES MVS OVR FA FRI NGT...SETTING UP COLDEST
NGT OF WINTER THUS FAR. RDGS FALL DN INTO THE SINGLE DIGITS ABV
ZERO IN MANY INLAND LCTNS...MSTLY TEENS ELSW (AND THIS IS W/O ANY
SNWCVR).
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
TEMPS START TO MODERATE (ALBEIT SLOLY) ON SAT AS THE FLOW BECOMES
SW WITH THE HIGH SLIDING OFFSHORE. HIGHS `WARM` SAT INTO THE LWR
TO MID 30S. LOWS "MILDER" SAT NIGHT...NEAR 20 NW TO NEAR 30 SE.
SEVERAL TROFS/AREAS OF LOW PRES WILL THEN ROTATE THRU THE MID-
ATLANTIC FROM SUN THRU EARLY NEXT WEEK. FCST MODEL SOUNDINGS SHOW
PLENTY OF DRY AIR IN PLACE AS EACH TROF MOVES THRU...AND GIVEN THE
TRAJECTORY OF EACH WAVE EXPECT THAT IT WILL BE DIFFICULT TO GET MUCH
IF ANY MEASURABLE PRECIP OUT OF THESE FEATURES. IF MODELS START TO
TREND WITH A TRACK FARTHER TO THE S THEN WILL NEED TO INCREASE THE
CHANCE OF PRECIP. WILL KEEP POPS CAPPED BETWEEN 20-30% AT THIS TIME.
AT ANY RATE...COLD AIR WILL REMAIN IN PLACE THRU AT LEAST EARLY NEXT
WEEK (ALTHO NOT AS COLD AS FRI-SAT). HIGHS WILL BE IN THE UPR 30S
NW/N TO MID 40S SE...LOWS IN THE LWR 20S NW/N TO NEAR 30 SE.
&&
.AVIATION /18Z WEDNESDAY THROUGH SUNDAY/... VFR CONDITIONS WILL
CONTINUE THRU FRIDAY. MAIN CONCERN TONIGHT THRU FRI WILL BE
WINDS...BY LATE TONIGHT WINDS WILL BE FROM THE SW AND GUSTY AS AN
ARTIC FRONT APPROACHES THE AREA. THURS AM WINDS WILL BECOME GUSTY
ESP ALONG THE COAST. A LOW PRESSURE SYSTEM MAY IMPACT THE AREA SUN
WITH A CHANCE OF PRECIPITATION AND POSSIBLY LOWERING AVIATION
CONDITIONS.
&&
.MARINE...
MARGINAL GALE FOR THE NRN COASTAL WTRS WILL CONT THRU THIS MORNING.
COLDER AIR IS JUST ABOUT THE REACH THE COASTAL WATERS WHERE GUSTS
AROUND 35 KT CUD REACH THE SFC. OTHERWISE...SCA`S UP FOR THE REST OF
THE WATERS UNTIL LATE MORN/EARLY AFTN.
WATERS CAN EXPECT A BRIEF RESPITE THIS AFTN AND EARLY EVENING AS
HIGH PRES BRIEFLY BUILDS IN. THEN SOUTHERLY WINDS BEGIN PICKING UP
ONCE AGAIN LATER TONIGHT. EXPECT YET EVEN COLDER AIR WITH THIS
FROPA...AND THINK THAT MODELS ARE SERIOUSLY UNDERDOING THE WINDS W/
THIS NEXT EVENT. CERTAINLY LOOKING AT HIGH END SCA`S FOR LATER
TONIGHT INTO EARLY THU...BUT ALSO POSSIBLY LO-END GALES. WILL ALLOW
DAY SHIFT TO MAKE DECISION...ONCE CURRENT HEADLINES HV EXPIRED.
&&
.CLIMATE...
VERY COLD WEATHER EXPECTED ON FRIDAY (THE 16TH) INTO THE MORNING OF
SAT (THE 17TH)...BUT SINCE THIS IS CLIMATOLOGICALLY RIGHT AROUND THE
COLDEST TIME OF YEAR...RECORD LOWS AND/OR RECORD LOW MAX
TEMPERATURES APPEAR UNLIKELY AT THE MAIN CLIMATE SITES
(RICHMOND/NORFOLK/SALISBURY). STILL...IT DOES LOOK TO BE THE COLDEST
CONDITIONS WE HAVE EXPERIENCED IN A FEW YEARS:
FCST HIGH FOR FRIDAY:
RICHMOND.....FRI FCST HIGH: 28 F (LAST TIME HIGH WAS COLDER THAN
30 F OCCURRED FEB 6TH 2007)
NORFOLK......FRI FCST HIGH: 30 F (LAST TIME HIGH WAS COLDER THAN
30 F OCCURRED JAN 28TH 2005)
SALISBURY....FRI FCST HIGH: 25 F (LAST TIME HIGH WAS COLDER THAN
25 F OCCURRED FEB 6TH 2007).
REC LOWS SAT JAN 17TH...
RIC... -1 (1977)
ORF... 5 (1977)
SBY... -6 (1965)
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 6 AM EST
FRIDAY FOR ANZ630>632.
SMALL CRAFT ADVISORY FROM 1 AM THURSDAY TO 6 AM EST FRIDAY FOR
ANZ633-650-652-654-656-658.
&&
$$
SYNOPSIS...ALB/MPR
NEAR TERM...ALB
SHORT TERM...ALB
LONG TERM...JRL
AVIATION...CY
MARINE...CY
CLIMATE...
000
FXUS61 KRNK 141701
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
1201 PM EST WED JAN 14 2009
.SYNOPSIS...
WEAK HIGH PRESSURE TODAY WILL QUICKLY GIVE WAY TO THE NEXT ARCTIC
FRONT BLASTING THROUGH TONIGHT. THIS FRONT WILL USHER IN THE
COLDEST AIR OF THE SEASON SO FAR...ALONG WITH SOME LIGHT SNOW
ACCUMULATIONS ON WESTERN MOUNTAIN SLOPES...AND GUSTY WINDS WITH
DANGEROUS WIND CHILLS AT TIMES.
&&
.NEAR TERM /THROUGH TONIGHT/...
MADE SOME MINOR ADJUSTMENTS IN TEMPERATURES AND CLOUD COVER
TODAY. TEMPERATURES HAVE BEEN WARMING MORE SLOWLY THAN EXPECTED
THIS MORNING. ELECTED TO TWEAKED HIGHS DOWN IN A FEW LOCATIONS.
ALSO...WITH CLOUDS ADVANCING QUICKLY EAST...DECIDED TO INCREASE
CLOUD COVER IN THE WEST THIS AFTERNOON. AS NEW MODELS COME IN WILL
LOOK AT THE SNOW AND WIND POTENTIAL FOR TONIGHT.
PREVIOUS DISCUSSION...
CURRENTLY ON THE INFRARED SATELLITE LOOP TOPS ARE WARMING OVER
THE MOUNTAINS AND AREA RADARS ARE SHOWING A TREND OF DECREASING
AREAL COVERAGE AND INTENSITY OF THE SNOW SHOWERS WEST OF THE BLUE
RIDGE. EXPECT VERY LITTLE TO BE LEFT AFTER 09Z.
THERE WILL BE A BREAK IN THE CLOUD COVER EARLY THIS MORNING...THEN
BY 15Z CLOUDS FROM THE NEXT CLIPPER WILL START TO SPREAD INTO THE
FORECAST AREA.
LOW OVER SOUTHERN IOWA THIS MORNING MOVES RAPIDLY EAST TODAY AND
PUSHES A FRONT THROUGH THE COUNTY WARNING AREA THIS EVENING. BEST
PRESSURE RISES BEHIND THIS SYSTEM ARE OVERNIGHT. MODELS SHOW
MOISTURE DEEPENING ENOUGH BY 03Z FOR WIDESPREAD UPSLOPE SNOW SHOWERS
IN THE WEST. HAVE SLIGHTLY RAISED PROBABILITY OF SNOW IN THE FAVORED
WESTERN AREAS AFTER THIS TIME.
CONDITIONS NOT IDEAL FOR ADV CRITERIA WINDS BEHIND FRONT AS
SUBSIDENCE INVERSION REMAINS HIGH AND PRESSURE RISES BEHIND FRONT
NOT PARTICULARLY IMPRESSIVE. STRONGEST 850 GRADIENT ACTUALLY FROM
SW RIGHT BEFORE FRONTAL PASSAGE. COULD GET SOME ISOLD GUSTS OVER 40
MPH ALONG HIGHEST RIDGES BEHIND FRONT IN THE MIDDLE OF THE
NIGHT. CROSS SECTIONS SHOWED POTENTIAL FOR WINDS ABOVE 40 KNOTS AT
THE HIGHEST ELEVATIONS...SO HAVE RAISED WINDS SPEEDS AND GUSTS
FROM 00-09Z BUT NO WIND ADVISORY POSTED AT THIS TIME.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
AIR MASS BEHIND ARCTIC FRONT WILL BRING COLDEST TEMPERATURES OF
THE SEASON SO FAR...WITH TEMPERATURES STEADY TO DROPPING DURING THE DAY
THURS. GRADIENT GRADUALLY DROPS OFF SO WINDS WILL BEGIN TO
DECREASE THROUGHOUT THE DAY...BUT WILL STILL RESULT IN WIND
CHILLS IN THE SINGLE DIGITS WEST...TO 20S IN THE EAST...AND THIS
DURING THE DAYTIME. MOISTURE BECOMES SHALLOW QUICKLY IN NW
UPSLOPE LOCATIONS BUT WITH CYCLONIC FLOW CONTINUING AND LOW LEVELS
COLD ENOUGH TO SUPPORT ICE CRYSTAL GROWTH THROUGH THE DAY...SOME
LIGHT ACCUMULATIONS EXPECTED TO CONTINUE MAINLY IN WV MTNS. USED
SNOW TO LIQUID RATIOS OF 20:1 OR HIGHER...RESULTING IN ANOTHER 1-3
INCHES IN FAVORED AREAS DURING THE DAY.
ANOTHER WEAKER WAVE FCST TO SWING THROUGH BY THURS EVENING...
PERHAPS KEEPING SOME SNOW SHWRS GOING ON WESTERN SLOPES...AND ALSO
TEMPORARILY INCREASING GRADIENT OVERNIGHT...SO AS TEMPS REALLY
PLUMMET WITH COLDEST LOW LEVEL THICKNESSES...WIND CHILLS WILL BE
AT THEIR COLDEST OVERNIGHT THURSDAY AND INTO FRIDAY. DID NOT MAKE
ANY SIGNIFICANT CHANGES TO TEMPS...ALTHOUGH MODERATED HIGHS
SLIGHTLY FOR FRI AND SAT PER GUIDANCE TRENDS...BUT DID INCREASE
WINDS THURS NIGHT AND INTO FRIDAY. THIS RESULTED IN COLDER WIND
CHILLS..WITH MANY LOCATIONS IN WEST MINUS 5 TO MINUS 10 THROUGH AT
LEAST MIDDAY FRIDAY. WILL CONTINUE TO HIGHLIGHT THIS IN THE
HAZARDOUS WEATHER OUTLOOK...BUT STILL TOO FAR OUT TO ISSUE THE
WIND CHILL ADVISORY. IT IS LOOKING MORE AND MORE LIKELY THAT IT
WILL EVENTUALLY BE NEEDED.
LOWS SATURDAY MORNING TRICKY AS HIGH SETTLES OVERHEAD SOME AREAS
WILL SEE EXCELLENT RADIATIONAL COOLING..BUT TRENDS ARE TO BRING
NEXT WAVE IN A LITTLE QUICKER...AND POSSIBLE SW WINDS AND WARM ADV
WITH HIGHER CLOUDS INTO THE WEST BEFORE DAWN...SO THIS WOULD LIMIT
HOW LOW TEMPS COULD GET IN AT LEAST PART OF THE REGION. TIMING OF
THIS COULD CHANGE THOUGH...SO MADE NO SIGNIFICANT CHANGES HERE
EITHER...OTHER THAN THE SLIGHT MODERATION OF HIGHS ON SATURDAY PER
LATEST GUIDANCE TRENDS AS WARM ADV LOOKS LIKE IT COULD BE STRONGER
THAN EARLIER THOUGHT. STILL...TEMPERATURES WAY BELOW NORMAL FOR
SATURDAY AND LIKELY NOT REACHING FREEZING AGAIN IN THE MOUNTAINS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
TEMPERATURES SHOULD CONTINUE TO GRADUALLY MODERATE INTO SUNDAY
AHEAD OF ANOTHER CONTINENTAL FRONT THAT WILL CROSS THE FORECAST
AREA. CONTINUED THE CHANCE OF SNOW WITH ITS PASSAGE SATURDAY NIGHT
INTO SUNDAY. KEPT LIGHT CHC POPS IN THE WESTERN MOUNTAINS SUNDAY
NIGHT INTO MONDAY. NEXT FRONT ARRIVES ON TUESDAY WITH CHANCE FOR
RAIN AND SNOW. LEANED EARLY NEXT WEEK TOWARDS THE ECMWF WITH
ADDITIONAL CLOUDS AND POPS...WHICH DIVES SYSTEM FURTHER SOUTH WITH
COASTAL LOW DEVELOPMENT COMPARED TO GFS. PLAYED TEMPERATURES CLOSE
TO HPCGUIDE.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
CHECK AIRMETS AND SIGMETS FOR TURBULENCE...ICING AND MOUNTAIN
OBSCURATIONS THIS AFTERNOON AND TONIGHT. MID AND HIGH LEVEL CLOUDS
SPREADING EAST INTO WESTERN PORTIONS OF CWA THIS AFTERNOON AHEAD OF
LOW PRESSURE IN THE OHIO VALLEY. THIS LOW WILL CROSS QUICKLY THROUGH
THE OHIO VALLEY THIS AFTERNOON AND WILL PUSH A COLD FRONT ACROSS THE
FORECAST AREA THIS EVENING. MVFR CEILINGS WITH MVFR/IFR SNOW SHOWERS
WILL DEVELOP AFTER 06Z BEHIND THE COLD FRONT IN THE MOUNTAINS. WINDS
WILL ALSO INCREASE FROM THE WEST TO NORTHWEST WITH GUSTS FROM 06-12Z
AROUND 40 KNOTS AT HIGHER ELEVATIONS.
DRIER AIR AND VFR CONDITIONS WILL COME IN ON THURSDAY NIGHT AND
FRIDAY ALONG WITH A LARGE HIGH AND ARCTIC AIR. ANOTHER STORM
ARRIVES SATURDAY NIGHT INTO SUNDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...SK
NEAR TERM...AMS/KK
SHORT TERM...SK
LONG TERM...KK
AVIATION...AMS/KK
000
FXUS61 KLWX 141626
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1126 AM EST WED JAN 14 2009
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFF THE COAST THIS AFTERNOON. AN ALBERTA
CLIPPER AND ITS ASSOCIATED COLD FRONT WILL PASS THROUGH WEDNESDAY
NIGHT INTO THURSDAY. BITTERLY COLD CONDITIONS ARE EXPECTED BEHIND
THIS SYSTEM THROUGH THE END OF THE WEEK AND FIRST PART OF THE
WEEKEND. ANOTHER SYSTEM MAY AFFECT THE REGION ON SUNDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
CLIPPER LOW WAS MOVING INTO THE OHIO VALLEY LATE THIS MORNING.
BAND OF HEAVY SNOW HAS SET UP RIGHT ALONG INTERSTATE 70 NEAR
COLUMBUS OHIO.
INFRARED IMAGERY INDICATES THAT MID AND HIGH CLOUDS ARE ON THE
INCREASE ACORSS OUR CWA WELL AHEAD OF THE CLIPPER LOW. SO...AFTER
THE MORNING SUNSINE THE AFTERNOON WILL BE MOSTLY CLOUDY.
SNOW WILL HOLD OFF UNTIL LATER THIS AFTERNOON TO MOVE INTO THE
HIGHLANDS PER 09Z SREFS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
LOW PRESSURE MOVES ACROSS THE NORTHERN CWA THIS EVENING. LOW
PRESSURE ITSELF WILL LEAD TO SNOW ACROSS THE ALLEGHENY HIGHLANDS
THIS EVENING. THEN AS NORTHWEST WINDS BRING IN ARCTIC
AIR...SNOW WILL CONTINUE IN UPSLOPE FASHION OVERNIGHT INTO
THURSDAY MORNING.
HAVE ISSUED A WINTER WEATHER ADVISORY FOR THE HIGHLANDS. HIGHEST
ACCUMS WILL BE WESTERN FACING SLOPES OF THE ALLGHENY HIGHLANDS
WITH LOW PRESSURE AND THEN UPSLOPE SNOW...2 TO 4 INCHES.
HOWEVER...BELIEVE THIS IS ONE OF THOSE SITUATIONS WHERE SNOW CAN
MAKE IT EAST OF THE FRONT INTO PLACES LIKE CUMBERLAND WHERE AN
INCH OR TWO CAN ACCUMULATE. EVEN FURTHER EAST AND SOUTH THAN
THAT...SOME ACCUMULATING SNOW MAY OCCUR INTO NORTHERN
MARYLAND...REST OF THE EASTERN WEST VIRGINIA PANHANDLE AND
NORTHERN SHENANDOAH VALLEY BUT RIGHT NOT EXPECT THIS TO BE BELOW 1
INCH. WILL ADD DETAIL IN THE AFTERNOON PACKAGE. WILL ALSO CONSIDER
WIND CHILL ISSUES ACROSS THE HIGHLANDS FOR LATE TONIGHT INTO
THURSDAY AS WELL.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
WINTER COLD HAS DEFINITELY SETTLED INTO THE MID ATLC. FOR EXAMPLE...
IN DC PROPER IT LIKELY WON/T GET ABOVE FREEZING UNTIL SUNDAY...AND
ONLY FOR A FEW HRS DURING THE AFTN. TWO STRAIGHT NIGHTS OF SUBZERO
AND SINGLE DIGIT WIND CHILLS ARE CLOSE AT HAND. ARCTIC AIR WILL
INVADE THE REGION EAST OF APLCNS AFTER A WINDY DAY ON THURS. AFTER
THE ARCTIC COLD FRONT SLIDES ACROSS THE AREA EARLY THURS MRNG /AND
DWPTS DROP INTO THE SINGLE DIGITS/ TEMPS WILL PLUMMET THRU THE REST
OF THE AFTN/EVNG HRS. BY LATE EVNG...TEMPS WILL ALREADY BE IN THE
UPPER TEENS ACROSS THE I-95 CORRIDOR. LOWS WILL BOTTOM OUT IN THE
LOWER TEENS FOR THE METRO AREA...SINGLE DIGITS FOR MUCH OF THE CNTRL
AND WRN PORTIONS OF THE CWA...AND A FEW SUBZERO MARKS ACROSS THE
HIGHER ELEVATIONS. THE BIGGER ISSUE W/ THIS IS THAT WINDS WILL STILL
BE SUBSIDING FROM A BREEZY AFTN W/ PEAK WIND GUSTS IN THE 30-35 MPH
RANGE.
BY LATE EVNG...SFC WINDS WILL STILL BE GUSTING INTO THE 15-20 MPH
RANGE FOR MUCH OF THE AREA. OVERNIGHT...OVERALL WIND SPEEDS WILL
DROP INTO THE 5-10 MPH RANGE...BUT WELL INTO THE OVERNIGHT HRS.
WIND CHILL PRODUCTS MAY BE WARRANTED...MAINLY WEST OF THE VA BLUE
RIDGE. EAST OF THE BLUE RIDGE...WINDS SHOULD BE LIGHT ENOUGH BY
THE TIME TEMPS DROP INTO THE LOWER TEENS. IF GUIDANCE SUGGESTS WINDS
WILL DECREASE QUICKER THAN CURRENT SOLUTIONS SUGGEST...MUCH LESS
AREA MAY NEED TO BE COVERED THO AMBIENT TEMPS WILL BE DANGEROUS
ENOUGH THAT THE PUBLIC SHOULD AT VERY LEAST BE WARY OF THE COLDEST
AIR OF THE SEASON WILL BE UPON US. HIGHS ON FRI BARELY OUT OF THE
TEENS...POSSIBLY BREACHING 20 DEGREES EAST OF I-95...A FEW SINGLE
DIGITS READING FOR HIGHS ACROSS EXTREME WRN PANHANDLE REGIONS OF WV.
SAME STORY FRIDAY NIGHT...JUST A BIT COLDER AND LESS WINDY. WITH
EVEN DRIER AIR /DWPTS WELL BELOW ZERO/ AS THE CENTER OF A STRONG
SFC HIGH PASSES OVER THE REGION...AMBIENT TEMPS WILL DROP INTO AT
LEAST SINGLE DIGITS FOR MUCH OF THE OHIO VLY ALL THE WAY TO THE
ATLC COAST. NO WIND CHILL PRODUCTS ANTICIPATED FOR OVERNIGHT FRI
W/ WINDS LIGHT/VRB.
BY THE END OF THE WEEK...THE LONGWAVE TROF WILL BE POSITIONED A BIT
FURTHER EAST...MAKING THE ARCTIC BLASTS ALSO DISPLACED FURTHER EAST
AS THE SLIDE SE ACROSS THE SRN END OF HUDSON BAY.
SAT...ANOTHER SERIES OF WEAK UPPER VORTS WILL SLIDE THRU THE GRT
LKS REGION. A SFC LOW LOOKS TO INITIALLY MAKE A FAST APPROACH
TOWARD THE CNTRL APLCNS FROM THE NW...BUT DISSIPATES OVER LAKE
ERIE AS A SECONDARY UPPER WAVE PUSHES DUE SOUTH INTO THE UPPER
MIDWEST LATE SAT. SLY WINDS WILL INCREASE UP THE ERN SEABOARD LATE
SAT...ADDING A BIT MORE LOW LEVEL MOISTURE A MAKING IT FEEL A BIT
LESS MISERABLE GOING INTO SUNDAY.
THE BEST CHANCE FOR AT LEAST LOW CHANCE SNOW PROBABILITIES LOOKS
TO BE SUNDAY AS THE LOW WASHES OUT AND THE INCOMING DYNAMICS OF
THE UPPER TROF PUSH THE DISSIPATING FRONT ACROSS THE REGION. THE
00Z EUROPEAN DOESN/T DISSIPATE THE LOW AND INSTEAD DEVELOPS A
NOR`EASTER FOR THE NEW ENGLAND STATES SUNDAY INTO EARLY MON...AN
UNLIKELY SCENARIO AT THIS TIME.
THEN...ONE AFTER ANOTHER...UPPER WAVES SLIDES DOWN THE SAME PATH
OVER THE GRT LKS REGION THRU THE MIDDLE OF NEXT WEEK. EACH ONE W/
AT LEAST A LOW CHANCE OF A FEW FLURRIES OR SCATTERED SNOW BANDS.
TUESDAY OF NEXT WEEK /AT THIS TIME/ SHOWS MODELS BACKING OFF FROM
EVEN LOW CHANCE SNOWS AS IT LOOKS LIKE A TRANSITION DAY FROM ONE OF
THE WEAK LOW PRESSURE SYSTEMS EXITING THE REGION OFF THE ATLC COAST.
TUE A TRANSITION DAY MEANING TEMPS STILL IN THE 20S DURING THE
MRNG HRS...WINDS GRADUALLY INCREASING DURING THE LATE MRNG AND
HIGHS JUST ABOVE FREEZING. MOS GUIDANCE HAS EVEN BACKED OFF ON
CLOUD COVER...FOR A MOSTLY SUNNY AFTN. ALL THIS LOOKS TO HINGE ON
THE TIMING AND PROGRESS OF ONE OF THESE UPPER VORTS THAT...FOR
EXAMPLE THE GFS PUSHES DOWN INTO THE DEEP SOUTH ON TUES...WHICH
WOULD BE A DRY SOLUTION FOR THE MID ATLC.
&&
.AVIATION /16Z WEDNESDAY THROUGH SUNDAY/...
BRZY CONDITIONS ATTM WL SUBSIDE THIS MRNG. VFR CONDS TDA/TNGT.
A COLD FRONT WILL SLIDE ACROSS THE REGION DURING THE MID MRNG HRS
THURSDAY...W/ W-NWLY WINDS QUICKLY PICKING UP BEHIND THE BOUNDARY.
SFC WINDS EXPECTED TO GUST 20-30KT...W/ A 40-50KT LL JET SLIDING
ACROSS THE REGION DURING THE AFTN. WEAKER GUSTS ON FRI AFTN...THEN
LITTLE CONCERN THRU EARLY NEXT WEEK OTHER THAN VERY COLD TEMPS.
&&
.MARINE...
DROPPED THE SMALL CRAFT ADVISORY AS OBS SHOW THAT THERE IS A
RELATIVE MINIMUM IN WIND ATTM. DO NOT EXPECT THEM TO INCREASE BACK
TO 20 KT UNTIL AFTER MIDNIGHT. SO HAVE ADJUSTED HEADLINES
ACCORDINGLY.
A LOW PRESSURE SYSTEM SLIDING INTO THE REGION OVERNIGHT WED INTO THE
EARLY MRNG HRS THURS. GUSTY WINDS WILL BRIEFLY PEAK NEAR GALE OVER
SRN/CNTRL PORTIONS OF THE BAY MIDDAY THURS...BUT MAINLY SOLID SCA
CONDITIONS OVER THE WATERS ALL-DAY THURSDAY. LESSER CONCERNS FOR
FRIDAY AFTN...AND FAIRLY LIGHT WINDS OVER THE WATER FOR THE COMING
WEEKEND.
&&
.CLIMATE...
VERY COLD WEATHER EXPECTED THIS FRIDAY /16 JAN/ INTO SATURDAY
MORNING /17 JAN/. HOWEVER...SINCE THIS IS NEAR THE CLIMATOLOGICALLY
COLDEST TIME OF YEAR...RECORD LOWS AND/OR RECORD LOW MAXIMUM
TEMPERATURES APPEAR UNLIKELY IN THE IMMEDIATE BALTIMORE/WASHINGTON
METROPOLITAN AREA. STILL...IT DOES LOOK TO BE THE COLDEST AIRMASS
FOR THE AREA IN OVER A DECADE. IT WAS NOTABLY COLDER FOR A FEW DAYS
IN MID JANUARY 1994 AT BWI/DCA/IAD.
BELOW ARE THE FORECAST MAXIMA FOR FRIDAY AND THE FORECAST MINIMA FOR
SATURDAY WITH THE MOST RECENT TIMES TEMPERATURES NEARED THESE
LEVELS...AS WELL AS RECORD LOWEST MAX ON 16 JAN AND RECORD LOW ON 17
JAN.
BWI...FRI FCST HIGH: 18 F /HIGHS OF 5-18 F IN MID JAN 1994 AND 19 F
ON JAN 10 2004 AND FEB 4 1996...RECORD LOW MAXIMUM OF 14 F IN 1893/
DCA...FRI JAN 16 FCST HIGH: 20 F /HIGH OF 17 F ON FEB 4 1996 AND 20
F ON FEB 3 1996 AND 21 F ON JAN 10 2004...RECORD LOW MAXIMUM OF 15 F
IN 1893/
IAD...FRI FCST HIGH: 18 F /HIGH OF 14 F ON FEB 4 1996 AND 19 F ON
JAN 17-18 1997 AND 20 ON FEB 5 2007...RECORD LOW MAXIMUM OF 14 IN
1972 AND 1996/
BWI...SAT FCST LOW: 1 F /LOW OF -1 F ON FEB 5 1996 AND 1 F ON JAN 19
1997...RECORD LOW OF -7 IN 1982/
DCA...SAT FCST LOW: 4 F /LOW OF 5 F ON FEB 5 1996...RECORD LOW OF -5
IN 1982/
IAD...SAT FCST LOW: 1 F /LOW OF -1 F ON FEB 7 1995...RECORD LOW OF
-7 IN 1982/
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 12 PM EST
THURSDAY FOR MDZ501-502.
VA...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 12 PM EST
THURSDAY FOR VAZ021.
WV...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 12 PM EST
THURSDAY FOR WVZ054-501>504.
MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 10 PM EST
THURSDAY FOR ANZ530>537.
&&
$$
SYNOPSIS...PELOQUIN
NEAR TERM...PELOQUIN
SHORT TERM...PELOQUIN
LONG TERM...GMS
AVIATION...ABW/GMS
MARINE...PELOQUIN/GMS
CLIMATE...BAJ/JRK/MRK
000
FXUS61 KRNK 141444
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
944 AM EST WED JAN 14 2009
.SYNOPSIS...
WEAK HIGH PRESSURE TODAY WILL QUICKLY GIVE WAY TO THE NEXT ARCTIC
FRONT BLASTING THROUGH TONIGHT. THIS FRONT WILL USHER IN THE
COLDEST AIR OF THE SEASON SO FAR...ALONG WITH SOME LIGHT SNOW
ACCUMULATIONS ON WESTERN MOUNTAIN SLOPES...AND GUSTY WINDS WITH
DANGEROUS WIND CHILLS AT TIMES.
&&
.NEAR TERM /THROUGH TONIGHT/...
MADE SOME MINOR ADJUSTMENTS IN TEMPERATURES AND CLOUD COVER
TODAY. TEMPERATURES HAVE BEEN WARMING MORE SLOWLY THAN EXPECTED
THIS MORNING. ELECTED TO TWEAKED HIGHS DOWN IN A FEW LOCATIONS.
ALSO...WITH CLOUDS ADVANCING QUICKLY EAST...DECIDED TO INCREASE
CLOUD COVER IN THE WEST THIS AFTERNOON. AS NEW MODELS COME IN WILL
LOOK AT THE SNOW AND WIND POTENTIAL FOR TONIGHT.
PREVIOUS DISCUSSION...
CURRENTLY ON THE INFRARED SATELLITE LOOP TOPS ARE WARMING OVER
THE MOUNTAINS AND AREA RADARS ARE SHOWING A TREND OF DECREASING
AREAL COVERAGE AND INTENSITY OF THE SNOW SHOWERS WEST OF THE BLUE
RIDGE. EXPECT VERY LITTLE TO BE LEFT AFTER 09Z.
THERE WILL BE A BREAK IN THE CLOUD COVER EARLY THIS MORNING...THEN
BY 15Z CLOUDS FROM THE NEXT CLIPPER WILL START TO SPREAD INTO THE
FORECAST AREA.
LOW OVER SOUTHERN IOWA THIS MORNING MOVES RAPIDLY EAST TODAY AND
PUSHES A FRONT THROUGH THE COUNTY WARNING AREA THIS EVENING. BEST
PRESSURE RISES BEHIND THIS SYSTEM ARE OVERNIGHT. MODELS SHOW
MOISTURE DEEPENING ENOUGH BY 03Z FOR WIDESPREAD UPSLOPE SNOW SHOWERS
IN THE WEST. HAVE SLIGHTLY RAISED PROBABILITY OF SNOW IN THE FAVORED
WESTERN AREAS AFTER THIS TIME.
CONDITIONS NOT IDEAL FOR ADV CRITERIA WINDS BEHIND FRONT AS
SUBSIDENCE INVERSION REMAINS HIGH AND PRESSURE RISES BEHIND FRONT
NOT PARTICULARLY IMPRESSIVE. STRONGEST 850 GRADIENT ACTUALLY FROM
SW RIGHT BEFORE FRONTAL PASSAGE. COULD GET SOME ISOLD GUSTS OVER 40
MPH ALONG HIGHEST RIDGES BEHIND FRONT IN THE MIDDLE OF THE
NIGHT. CROSS SECTIONS SHOWED POTENTIAL FOR WINDS ABOVE 40 KNOTS AT
THE HIGHEST ELEVATIONS...SO HAVE RAISED WINDS SPEEDS AND GUSTS
FROM 00-09Z BUT NO WIND ADVISORY POSTED AT THIS TIME.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
AIR MASS BEHIND ARCTIC FRONT WILL BRING COLDEST TEMPERATURES OF
THE SEASON SO FAR...WITH TEMPERATURES STEADY TO DROPPING DURING THE DAY
THURS. GRADIENT GRADUALLY DROPS OFF SO WINDS WILL BEGIN TO
DECREASE THROUGHOUT THE DAY...BUT WILL STILL RESULT IN WIND
CHILLS IN THE SINGLE DIGITS WEST...TO 20S IN THE EAST...AND THIS
DURING THE DAYTIME. MOISTURE BECOMES SHALLOW QUICKLY IN NW
UPSLOPE LOCATIONS BUT WITH CYCLONIC FLOW CONTINUING AND LOW LEVELS
COLD ENOUGH TO SUPPORT ICE CRYSTAL GROWTH THROUGH THE DAY...SOME
LIGHT ACCUMULATIONS EXPECTED TO CONTINUE MAINLY IN WV MTNS. USED
SNOW TO LIQUID RATIOS OF 20:1 OR HIGHER...RESULTING IN ANOTHER 1-3
INCHES IN FAVORED AREAS DURING THE DAY.
ANOTHER WEAKER WAVE FCST TO SWING THROUGH BY THURS EVENING...
PERHAPS KEEPING SOME SNOW SHWRS GOING ON WESTERN SLOPES...AND ALSO
TEMPORARILY INCREASING GRADIENT OVERNIGHT...SO AS TEMPS REALLY
PLUMMET WITH COLDEST LOW LEVEL THICKNESSES...WIND CHILLS WILL BE
AT THEIR COLDEST OVERNIGHT THURSDAY AND INTO FRIDAY. DID NOT MAKE
ANY SIGNIFICANT CHANGES TO TEMPS...ALTHOUGH MODERATED HIGHS
SLIGHTLY FOR FRI AND SAT PER GUIDANCE TRENDS...BUT DID INCREASE
WINDS THURS NIGHT AND INTO FRIDAY. THIS RESULTED IN COLDER WIND
CHILLS..WITH MANY LOCATIONS IN WEST MINUS 5 TO MINUS 10 THROUGH AT
LEAST MIDDAY FRIDAY. WILL CONTINUE TO HIGHLIGHT THIS IN THE
HAZARDOUS WEATHER OUTLOOK...BUT STILL TOO FAR OUT TO ISSUE THE
WIND CHILL ADVISORY. IT IS LOOKING MORE AND MORE LIKELY THAT IT
WILL EVENTUALLY BE NEEDED.
LOWS SATURDAY MORNING TRICKY AS HIGH SETTLES OVERHEAD SOME AREAS
WILL SEE EXCELLENT RADIATIONAL COOLING..BUT TRENDS ARE TO BRING
NEXT WAVE IN A LITTLE QUICKER...AND POSSIBLE SW WINDS AND WARM ADV
WITH HIGHER CLOUDS INTO THE WEST BEFORE DAWN...SO THIS WOULD LIMIT
HOW LOW TEMPS COULD GET IN AT LEAST PART OF THE REGION. TIMING OF
THIS COULD CHANGE THOUGH...SO MADE NO SIGNIFICANT CHANGES HERE
EITHER...OTHER THAN THE SLIGHT MODERATION OF HIGHS ON SATURDAY PER
LATEST GUIDANCE TRENDS AS WARM ADV LOOKS LIKE IT COULD BE STRONGER
THAN EARLIER THOUGHT. STILL...TEMPERATURES WAY BELOW NORMAL FOR
SATURDAY AND LIKELY NOT REACHING FREEZING AGAIN IN THE MOUNTAINS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
TEMPERATURES SHOULD CONTINUE TO GRADUALLY MODERATE INTO SUNDAY
AHEAD OF ANOTHER CONTINENTAL FRONT THAT WILL CROSS THE FORECAST
AREA. CONTINUED THE CHANCE OF SNOW WITH ITS PASSAGE SATURDAY NIGHT
INTO SUNDAY. KEPT LIGHT CHC POPS IN THE WESTERN MOUNTAINS SUNDAY
NIGHT INTO MONDAY. NEXT FRONT ARRIVES ON TUESDAY WITH CHANCE FOR
RAIN AND SNOW. LEANED EARLY NEXT WEEK TOWARDS THE ECMWF WITH
ADDITIONAL CLOUDS AND POPS...WHICH DIVES SYSTEM FURTHER SOUTH WITH
COASTAL LOW DEVELOPMENT COMPARED TO GFS. PLAYED TEMPERATURES CLOSE
TO HPCGUIDE.
&&
.AVIATION /15Z WEDNESDAY THROUGH SUNDAY/...
SCATTERED TO BROKEN MVFR CLOUDS WILL CONTINUE TO DISSIPATE THIS
MORNING OVER THE MOUNTAINS. THE SKY WILL BE VFR ALONG AND EAST OF
THE BLUE RIDGE.
A COLD FRONT WILL GRADUALLY COME AROUND TO THE SOUTHWEST AD SOUTH
AHEAD OF THE NEXT LOW PRESSURE SYSTEM. THIS LOW WILL CROSS QUICKLY
THROUGH THE OHIO VALLEY TODAY AND WILL PUSH A COLD FRONT ACROSS
THE FORECAST AREA THIS EVENING. MVFR CEILINGS WITH MVFR/IFR SNOW
SHOWERS WILL DEVELOP AFTER 06Z BEHIND THE COLD FRONT IN THE
MOUNTAINS. WINDS WILL ALSO INCREASE FROM THE WEST TO NORTHWEST
WITH GUSTS FROM 06-12Z AROUND 40 KNOTS AT HIGHER ELEVATIONS.
DRIER AIR AND VFR CONDITIONS WILL COME IN ON THURSDAY NIGHT AND
FRIDAY ALONG WITH A LARGE HIGH AND ARCTIC AIR. ANOTHER STORM
ARRIVES SATURDAY NIGHT INTO SUNDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...SK
NEAR TERM...AMS/KK
SHORT TERM...SK
LONG TERM...KK
AVIATION...AMS
000
FXUS61 KRNK 141210
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
710 AM EST WED JAN 14 2009
.SYNOPSIS...
WEAK HIGH PRESSURE TODAY WILL QUICKLY GIVE WAY TO THE NEXT ARCTIC
FRONT BLASTING THROUGH TONIGHT. THIS FRONT WILL USHER IN THE
COLDEST AIR OF THE SEASON SO FAR...ALONG WITH SOME LIGHT SNOW
ACCUMULATIONS ON WESTERN MOUNTAIN SLOPES...AND GUSTY WINDS WITH
DANGEROUS WIND CHILLS AT TIMES.
&&
.NEAR TERM /THROUGH TONIGHT/...
CURRENTLY ON THE INFRARED SATELLITE LOOP TOPS ARE WARMING OVER THE
MOUNTAINS AND AREA RADARS ARE SHOWING A TREND OF DECREASING AREAL
COVERAGE AND INTENSITY OF THE SNOW SHOWERS WEST OF THE BLUE RIDGE.
EXPECT VERY LITTLE TO BE LEFT AFTER 09Z.
THERE WILL BE A BREAK IN THE CLOUD COVER EARLY THIS MORNING...THEN
BY 15Z CLOUDS FROM THE NEXT CLIPPER WILL START TO SPREAD INTO THE
FORECAST AREA.
LOW OVER SOUTHERN IOWA THIS MORNING MOVES RAPIDLY EAST TODAY AND
PUSHES A FRONT THROUGH THE COUNTY WARNING AREA THIS EVENING. BEST
PRESSURE RISES BEHIND THIS SYSTEM ARE OVERNIGHT. MODELS SHOW
MOISTURE DEEPENING ENOUGH BY 03Z FOR WIDESPREAD UPSLOPE SNOW SHOWERS
IN THE WEST. HAVE SLIGHTLY RAISED PROBABILITY OF SNOW IN THE FAVORED
WESTERN AREAS AFTER THIS TIME.
CONDITIONS NOT IDEAL FOR ADV CRITERIA WINDS BEHIND FRONT AS
SUBSIDENCE INVERSION REMAINS HIGH AND PRESSURE RISES BEHIND FRONT
NOT PARTICULARLY IMPRESSIVE. STRONGEST 850 GRADIENT ACTUALLY FROM
SW RIGHT BEFORE FRONTAL PASSAGE. COULD GET SOME ISOLD GUSTS OVER 40
MPH ALONG HIGHEST RIDGES BEHIND FRONT IN THE MIDDLE OF THE
NIGHT. CROSS SECTIONS SHOWED POTENTIAL FOR WINDS ABOVE 40 KNOTS AT
THE HIGHEST ELEVATIONS...SO HAVE RAISED WINDS SPEEDS AND GUSTS
FROM 00-09Z BUT NO WIND ADVISORY POSTED AT THIS TIME.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
AIR MASS BEHIND ARCTIC FRONT WILL BRING COLDEST TEMPERATURES OF
THE SEASON SO FAR...WITH TEMPERATURES STEADY TO DROPPING DURING THE DAY
THURS. GRADIENT GRADUALLY DROPS OFF SO WINDS WILL BEGIN TO
DECREASE THROUGHOUT THE DAY...BUT WILL STILL RESULT IN WIND
CHILLS IN THE SINGLE DIGITS WEST...TO 20S IN THE EAST...AND THIS
DURING THE DAYTIME. MOISTURE BECOMES SHALLOW QUICKLY IN NW
UPSLOPE LOCATIONS BUT WITH CYCLONIC FLOW CONTINUING AND LOW LEVELS
COLD ENOUGH TO SUPPORT ICE CRYSTAL GROWTH THROUGH THE DAY...SOME
LIGHT ACCUMULATIONS EXPECTED TO CONTINUE MAINLY IN WV MTNS. USED
SNOW TO LIQUID RATIOS OF 20:1 OR HIGHER...RESULTING IN ANOTHER 1-3
INCHES IN FAVORED AREAS DURING THE DAY.
ANOTHER WEAKER WAVE FCST TO SWING THROUGH BY THURS EVENING...
PERHAPS KEEPING SOME SNOW SHWRS GOING ON WESTERN SLOPES...AND ALSO
TEMPORARILY INCREASING GRADIENT OVERNIGHT...SO AS TEMPS REALLY
PLUMMET WITH COLDEST LOW LEVEL THICKNESSES...WIND CHILLS WILL BE
AT THEIR COLDEST OVERNIGHT THURSDAY AND INTO FRIDAY. DID NOT MAKE
ANY SIGNIFICANT CHANGES TO TEMPS...ALTHOUGH MODERATED HIGHS
SLIGHTLY FOR FRI AND SAT PER GUIDANCE TRENDS...BUT DID INCREASE
WINDS THURS NIGHT AND INTO FRIDAY. THIS RESULTED IN COLDER WIND
CHILLS..WITH MANY LOCATIONS IN WEST MINUS 5 TO MINUS 10 THROUGH AT
LEAST MIDDAY FRIDAY. WILL CONTINUE TO HIGHLIGHT THIS IN THE
HAZARDOUS WEATHER OUTLOOK...BUT STILL TOO FAR OUT TO ISSUE THE
WIND CHILL ADVISORY. IT IS LOOKING MORE AND MORE LIKELY THAT IT
WILL EVENTUALLY BE NEEDED.
LOWS SATURDAY MORNING TRICKY AS HIGH SETTLES OVERHEAD SOME AREAS
WILL SEE EXCELLENT RADIATIONAL COOLING..BUT TRENDS ARE TO BRING
NEXT WAVE IN A LITTLE QUICKER...AND POSSIBLE SW WINDS AND WARM ADV
WITH HIGHER CLOUDS INTO THE WEST BEFORE DAWN...SO THIS WOULD LIMIT
HOW LOW TEMPS COULD GET IN AT LEAST PART OF THE REGION. TIMING OF
THIS COULD CHANGE THOUGH...SO MADE NO SIGNIFICANT CHANGES HERE
EITHER...OTHER THAN THE SLIGHT MODERATION OF HIGHS ON SATURDAY PER
LATEST GUIDANCE TRENDS AS WARM ADV LOOKS LIKE IT COULD BE STRONGER
THAN EARLIER THOUGHT. STILL...TEMPERATURES WAY BELOW NORMAL FOR
SATURDAY AND LIKELY NOT REACHING FREEZING AGAIN IN THE MOUNTAINS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
TEMPERATURES SHOULD CONTINUE TO GRADUALLY MODERATE INTO SUNDAY
AHEAD OF ANOTHER CONTINENTAL FRONT THAT WILL CROSS THE FORECAST
AREA. CONTINUED THE CHANCE OF SNOW WITH ITS PASSAGE SATURDAY NIGHT
INTO SUNDAY. KEPT LIGHT CHC POPS IN THE WESTERN MOUNTAINS SUNDAY
NIGHT INTO MONDAY. NEXT FRONT ARRIVES ON TUESDAY WITH CHANCE FOR
RAIN AND SNOW. LEANED EARLY NEXT WEEK TOWARDS THE ECMWF WITH
ADDITIONAL CLOUDS AND POPS...WHICH DIVES SYSTEM FURTHER SOUTH WITH
COASTAL LOW DEVELOPMENT COMPARED TO GFS. PLAYED TEMPERATURES CLOSE
TO HPCGUIDE.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
SCATTERED TO BROKEN MVFR CLOUDS WILL CONTINUE TO DISSIPATE THIS
MORNING OVER THE MOUNTAINS. THE SKY WILL BE VFR ALONG AND EAST OF
THE BLUE RIDGE.
A COLD FRONT WILL GRADUALLY COME AROUND TO THE SOUTHWEST AD SOUTH
AHEAD OF THE NEXT LOW PRESSURE SYSTEM. THIS LOW WILL CROSS QUICKLY
THROUGH THE OHIO VALLEY TODAY AND WILL PUSH A COLD FRONT ACROSS
THE FORECAST AREA THIS EVENING. MVFR CEILINGS WITH MVFR/IFR SNOW
SHOWERS WILL DEVELOP AFTER 06Z BEHIND THE COLD FRONT IN THE
MOUNTAINS. WINDS WILL ALSO INCREASE FROM THE WEST TO NORTHWEST
WITH GUSTS FROM 06-12Z AROUND 40 KNOTS AT HIGHER ELEVATIONS.
DRIER AIR AND VFR CONDITIONS WILL COME IN ON THURSDAY NIGHT AND
FRIDAY ALONG WITH A LARGE HIGH AND ARCTIC AIR. ANOTHER STORM
ARRIVES SATURDAY NIGHT INTO SUNDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...SK
NEAR TERM...AMS
SHORT TERM...SK
LONG TERM...KK
AVIATION...AMS
000
FXUS61 KRNK 141136
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
636 AM EST WED JAN 14 2009
.SYNOPSIS...
WEAK HIGH PRESSURE TODAY WILL QUICKLY GIVE WAY TO THE NEXT ARCTIC
FRONT BLASTING THROUGH TONIGHT. THIS FRONT WILL USHER IN THE
COLDEST AIR OF THE SEASON SO FAR...ALONG WITH SOME LIGHT SNOW
ACCUMULATIONS ON WESTERN MOUNTAIN SLOPES...AND GUSTY WINDS WITH
DANGEROUS WIND CHILLS AT TIMES.
&&
.NEAR TERM /THROUGH TONIGHT/...
CURRENTLY ON THE INFRARED SATELLITE LOOP TOPS ARE WARMING OVER THE
MOUNTAINS AND AREA RADARS ARE SHOWING A TREND OF DECREASING AREAL
COVERAGE AND INTENSITY OF THE SNOW SHOWERS WEST OF THE BLUE RIDGE.
EXPECT VERY LITTLE TO BE LEFT AFTER 09Z.
THERE WILL BE A BREAK IN THE CLOUD COVER EARLY THIS MORNING...THEN
BY 15Z CLOUDS FROM THE NEXT CLIPPER WILL START TO SPREAD INTO THE
FORECAST AREA.
LOW OVER SOUTHERN IOWA THIS MORNING MOVES RAPIDLY EAST TODAY AND
PUSHES A FRONT THROUGH THE COUNTY WARNING AREA THIS EVENING. BEST
PRESSURE RISES BEHIND THIS SYSTEM ARE OVERNIGHT. MODELS SHOW
MOISTURE DEEPENING ENOUGH BY 03Z FOR WIDESPREAD UPSLOPE SNOW SHOWERS
IN THE WEST. HAVE SLIGHTLY RAISED PROBABILITY OF SNOW IN THE FAVORED
WESTERN AREAS AFTER THIS TIME.
CONDITIONS NOT IDEAL FOR ADV CRITERIA WINDS BEHIND FRONT AS
SUBSIDENCE INVERSION REMAINS HIGH AND PRESSURE RISES BEHIND FRONT
NOT PARTICULARLY IMPRESSIVE. STRONGEST 850 GRADIENT ACTUALLY FROM
SW RIGHT BEFORE FRONTAL PASSAGE. COULD GET SOME ISOLD GUSTS OVER 40
MPH ALONG HIGHEST RIDGES BEHIND FRONT IN THE MIDDLE OF THE
NIGHT...BUT AT THIS TIME DO NOT THINK IT WILL BE WIDESPREAD ENOUGH FOR
WIND ADVISORY.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
AIR MASS BEHIND ARCTIC FRONT WILL BRING COLDEST TEMPERATURES OF
THE SEASON SO FAR...WITH TEMPERATURES STEADY TO DROPPING DURING THE DAY
THURS. GRADIENT GRADUALLY DROPS OFF SO WINDS WILL BEGIN TO
DECREASE THROUGHOUT THE DAY...BUT WILL STILL RESULT IN WIND
CHILLS IN THE SINGLE DIGITS WEST...TO 20S IN THE EAST...AND THIS
DURING THE DAYTIME. MOISTURE BECOMES SHALLOW QUICKLY IN NW
UPSLOPE LOCATIONS BUT WITH CYCLONIC FLOW CONTINUING AND LOW LEVELS
COLD ENOUGH TO SUPPORT ICE CRYSTAL GROWTH THROUGH THE DAY...SOME
LIGHT ACCUMULATIONS EXPECTED TO CONTINUE MAINLY IN WV MTNS. USED
SNOW TO LIQUID RATIOS OF 20:1 OR HIGHER...RESULTING IN ANOTHER 1-3
INCHES IN FAVORED AREAS DURING THE DAY.
ANOTHER WEAKER WAVE FCST TO SWING THROUGH BY THURS EVENING...
PERHAPS KEEPING SOME SNOW SHWRS GOING ON WESTERN SLOPES...AND ALSO
TEMPORARILY INCREASING GRADIENT OVERNIGHT...SO AS TEMPS REALLY
PLUMMET WITH COLDEST LOW LEVEL THICKNESSES...WIND CHILLS WILL BE
AT THEIR COLDEST OVERNIGHT THURSDAY AND INTO FRIDAY. DID NOT MAKE
ANY SIGNIFICANT CHANGES TO TEMPS...ALTHOUGH MODERATED HIGHS
SLIGHTLY FOR FRI AND SAT PER GUIDANCE TRENDS...BUT DID INCREASE
WINDS THURS NIGHT AND INTO FRIDAY. THIS RESULTED IN COLDER WIND
CHILLS..WITH MANY LOCATIONS IN WEST MINUS 5 TO MINUS 10 THROUGH AT
LEAST MIDDAY FRIDAY. WILL CONTINUE TO HIGHLIGHT THIS IN THE
HAZARDOUS WEATHER OUTLOOK...BUT STILL TOO FAR OUT TO ISSUE THE
WIND CHILL ADVISORY. IT IS LOOKING MORE AND MORE LIKELY THAT IT
WILL EVENTUALLY BE NEEDED.
LOWS SATURDAY MORNING TRICKY AS HIGH SETTLES OVERHEAD SOME AREAS
WILL SEE EXCELLENT RADIATIONAL COOLING..BUT TRENDS ARE TO BRING
NEXT WAVE IN A LITTLE QUICKER...AND POSSIBLE SW WINDS AND WARM ADV
WITH HIGHER CLOUDS INTO THE WEST BEFORE DAWN...SO THIS WOULD LIMIT
HOW LOW TEMPS COULD GET IN AT LEAST PART OF THE REGION. TIMING OF
THIS COULD CHANGE THOUGH...SO MADE NO SIGNIFICANT CHANGES HERE
EITHER...OTHER THAN THE SLIGHT MODERATION OF HIGHS ON SATURDAY PER
LATEST GUIDANCE TRENDS AS WARM ADV LOOKS LIKE IT COULD BE STRONGER
THAN EARLIER THOUGHT. STILL...TEMPERATURES WAY BELOW NORMAL FOR
SATURDAY AND LIKELY NOT REACHING FREEZING AGAIN IN THE MOUNTAINS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
TEMPERATURES SHOULD CONTINUE TO GRADUALLY MODERATE INTO SUNDAY
AHEAD OF ANOTHER CONTINENTAL FRONT THAT WILL CROSS THE FORECAST
AREA. CONTINUED THE CHANCE OF SNOW WITH ITS PASSAGE SATURDAY NIGHT
INTO SUNDAY. KEPT LIGHT CHC POPS IN THE WESTERN MOUNTAINS SUNDAY
NIGHT INTO MONDAY. NEXT FRONT ARRIVES ON TUESDAY WITH CHANCE FOR
RAIN AND SNOW. LEANED EARLY NEXT WEEK TOWARDS THE ECMWF WITH
ADDITIONAL CLOUDS AND POPS...WHICH DIVES SYSTEM FURTHER SOUTH WITH
COASTAL LOW DEVELOPMENT COMPARED TO GFS. PLAYED TEMPERATURES CLOSE
TO HPCGUIDE.
&&
.AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
SCATTERED TO BROKEN MVFR CLOUDS WILL CONTINUE TO DISSIPATE THIS
MORNING OVER THE MOUNTAINS. THE SKY WILL BE VFR ALONG AND EAST OF
THE BLUE RIDGE.
A COLD FRONT WILL GRADUALLY COME AROUND TO THE SOUTHWEST AD SOUTH
AHEAD OF THE NEXT LOW PRESSURE SYSTEM. THIS LOW WILL CROSS QUICKLY
THROUGH THE OHIO VALLEY TODAY AND WILL PUSH A COLD FRONT ACROSS
THE FORECAST AREA THIS EVENING. MVFR CEILINGS WITH MVFR/IFR SNOW
SHOWERS WILL DEVELOP AFTER 06Z BEHIND THE COLD FRONT IN THE
MOUNTAINS. WINDS WILL ALSO INCREASE FROM THE WEST TO NORTHWEST
WITH GUSTS FROM 06-12Z AROUND 40 KNOTS AT HIGHER ELEVATIONS.
DRIER AIR AND VFR CONDITIONS WILL COME IN ON THURSDAY NIGHT AND
FRIDAY ALONG WITH A LARGE HIGH AND ARCTIC AIR. ANOTHER STORM
ARRIVES SATURDAY NIGHT INTO SUNDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...SK
NEAR TERM...AMS
SHORT TERM...SK
LONG TERM...KK
AVIATION...AMS
000
FXUS61 KRNK 140933
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
433 AM EST WED JAN 14 2009
.SYNOPSIS...
WEAK HIGH PRESSURE TODAY WILL QUICKLY GIVE WAY TO THE NEXT ARCTIC
FRONT BLASTING THROUGH TONIGHT. THIS FRONT WILL USHER IN THE
COLDEST AIR OF THE SEASON SO FAR...ALONG WITH SOME LIGHT SNOW
ACCUMULATIONS ON WESTERN MOUNTAIN SLOPES...AND GUSTY WINDS WITH
DANGEROUS WIND CHILLS AT TIMES.
&&
.NEAR TERM /THROUGH TONIGHT/...
CURRENTLY ON THE INFRARED SATELLITE LOOP TOPS ARE WARMING OVER THE
MOUNTAINS AND AREA RADARS ARE SHOWING A TREND OF DECREASING AREAL
COVERAGE AND INTENSITY OF THE SNOW SHOWERS WEST OF THE BLUE RIDGE.
EXPECT VERY LITTLE TO BE LEFT AFTER 09Z.
THERE WILL BE A BREAK IN THE CLOUD COVER EARLY THIS MORNING...THEN
BY 15Z CLOUDS FROM THE NEXT CLIPPER WILL START TO SPREAD INTO THE
FORECAST AREA.
LOW OVER SOUTHERN IOWA THIS MORNING MOVES RAPIDLY EAST TODAY AND
PUSHES A FRONT THROUGH THE COUNTY WARNING AREA THIS EVENING. BEST
PRESSURE RISES BEHIND THIS SYSTEM ARE OVERNIGHT. MODELS SHOW
MOISTURE DEEPENING ENOUGH BY 03Z FOR WIDESPREAD UPSLOPE SNOW SHOWERS
IN THE WEST. HAVE SLIGHTLY RAISED PROBABILITY OF SNOW IN THE FAVORED
WESTERN AREAS AFTER THIS TIME.
CONDITIONS NOT IDEAL FOR ADV CRITERIA WINDS BEHIND FRONT AS
SUBSIDENCE INVERSION REMAINS HIGH AND PRESSURE RISES BEHIND FRONT
NOT PARTICULARLY IMPRESSIVE. STRONGEST 850 GRADIENT ACTUALLY FROM
SW RIGHT BEFORE FRONTAL PASSAGE. COULD GET SOME ISOLD GUSTS OVER 40
MPH ALONG HIGHEST RIDGES BEHIND FRONT IN THE MIDDLE OF THE
NIGHT...BUT AT THIS TIME DO NOT THINK IT WILL BE WIDESPREAD ENOUGH FOR
WIND ADVISORY.
&&
.SHORT TERM /THURSDAY THROUGH SATURDAY/...
AIR MASS BEHIND ARCTIC FRONT WILL BRING COLDEST TEMPERATURES OF
THE SEASON SO FAR...WITH TEMPERATURES STEADY TO DROPPING DURING THE DAY
THURS. GRADIENT GRADUALLY DROPS OFF SO WINDS WILL BEGIN TO
DECREASE THROUGHOUT THE DAY...BUT WILL STILL RESULT IN WIND
CHILLS IN THE SINGLE DIGITS WEST...TO 20S IN THE EAST...AND THIS
DURING THE DAYTIME. MOISTURE BECOMES SHALLOW QUICKLY IN NW
UPSLOPE LOCATIONS BUT WITH CYCLONIC FLOW CONTINUING AND LOW LEVELS
COLD ENOUGH TO SUPPORT ICE CRYSTAL GROWTH THROUGH THE DAY...SOME
LIGHT ACCUMULATIONS EXPECTED TO CONTINUE MAINLY IN WV MTNS. USED
SNOW TO LIQUID RATIOS OF 20:1 OR HIGHER...RESULTING IN ANOTHER 1-3
INCHES IN FAVORED AREAS DURING THE DAY.
ANOTHER WEAKER WAVE FCST TO SWING THROUGH BY THURS EVENING...
PERHAPS KEEPING SOME SNOW SHWRS GOING ON WESTERN SLOPES...AND ALSO
TEMPORARILY INCREASING GRADIENT OVERNIGHT...SO AS TEMPS REALLY
PLUMMET WITH COLDEST LOW LEVEL THICKNESSES...WIND CHILLS WILL BE
AT THEIR COLDEST OVERNIGHT THURSDAY AND INTO FRIDAY. DID NOT MAKE
ANY SIGNIFICANT CHANGES TO TEMPS...ALTHOUGH MODERATED HIGHS
SLIGHTLY FOR FRI AND SAT PER GUIDANCE TRENDS...BUT DID INCREASE
WINDS THURS NIGHT AND INTO FRIDAY. THIS RESULTED IN COLDER WIND
CHILLS..WITH MANY LOCATIONS IN WEST MINUS 5 TO MINUS 10 THROUGH AT
LEAST MIDDAY FRIDAY. WILL CONTINUE TO HIGHLIGHT THIS IN THE
HAZARDOUS WEATHER OUTLOOK...BUT STILL TOO FAR OUT TO ISSUE THE
WIND CHILL ADVISORY. IT IS LOOKING MORE AND MORE LIKELY THAT IT
WILL EVENTUALLY BE NEEDED.
LOWS SATURDAY MORNING TRICKY AS HIGH SETTLES OVERHEAD SOME AREAS
WILL SEE EXCELLENT RADIATIONAL COOLING..BUT TRENDS ARE TO BRING
NEXT WAVE IN A LITTLE QUICKER...AND POSSIBLE SW WINDS AND WARM ADV
WITH HIGHER CLOUDS INTO THE WEST BEFORE DAWN...SO THIS WOULD LIMIT
HOW LOW TEMPS COULD GET IN AT LEAST PART OF THE REGION. TIMING OF
THIS COULD CHANGE THOUGH...SO MADE NO SIGNIFICANT CHANGES HERE
EITHER...OTHER THAN THE SLIGHT MODERATION OF HIGHS ON SATURDAY PER
LATEST GUIDANCE TRENDS AS WARM ADV LOOKS LIKE IT COULD BE STRONGER
THAN EARLIER THOUGHT. STILL...TEMPERATURES WAY BELOW NORMAL FOR
SATURDAY AND LIKELY NOT REACHING FREEZING AGAIN IN THE MOUNTAINS.
&&
.LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/...
TEMPERATURES SHOULD CONTINUE TO GRADUALLY MODERATE INTO SUNDAY
AHEAD OF ANOTHER CONTINENTAL FRONT THAT WILL CROSS THE FORECAST
AREA. CONTINUED THE CHANCE OF SNOW WITH ITS PASSAGE SATURDAY NIGHT
INTO SUNDAY. KEPT LIGHT CHC POPS IN THE WESTERN MOUNTAINS SUNDAY
NIGHT INTO MONDAY. NEXT FRONT ARRIVES ON TUESDAY WITH CHANCE FOR
RAIN AND SNOW. LEANED EARLY NEXT WEEK TOWARDS THE ECMWF WITH
ADDITIONAL CLOUDS AND POPS...WHICH DIVES SYSTEM FURTHER SOUTH WITH
COASTAL LOW DEVELOPMENT COMPARED TO GFS. PLAYED TEMPERATURES CLOSE
TO HPCGUIDE.
&&
.AVIATION /09Z WEDNESDAY THROUGH SUNDAY/...
A COLD FRONT WILL TRAVEL EAST OFF THE COAST TONIGHT. MVFR/IFR
CIGS IN SNOW SHOWERS IN THE MOUNTAINS WILL GRADUALLY DIMINISH BY
09Z. ELSEWHERE...VFR CONDITIONS ARE EXPECTED. WINDS GUSTS WILL
ALSO DIMINISH AS LOW LEVEL WINDS BACK AHEAD OF THE NEST
APPROACHING SHORT WAVE.
CONDITIONS WILL REMAIN MVFR AT BLF/LWB THROUGH DAYBREAK BEFORE DRIER
AIR SCATTERS OUT THE CEILINGS. ELSEWHERE...LOOK FOR VFR CIGS
OVERNIGHT THEN CLEARING.
A STRONGER ARCTIC COLD FRONT WILL CROSS THE AREA WEDNESDAY NIGHT
WITH MVFR CIGS/VSBYS AND SNOW SHOWERS AGAIN IN THE MOUNTAINS
THROUGH THURSDAY MORNING. ALSO STRONG WINDS AT HIGHER ELEVATIONS
ARE EXPECTED THROUGH THURSDAY. ANOTHER STORM ARRIVES SATURDAY
NIGHT INTO SUNDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...SK
NEAR TERM...AMS
SHORT TERM...SK
LONG TERM...KK
AVIATION...AMS
000
FXUS61 KLWX 140854
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
354 AM EST WED JAN 14 2009
.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER THE REGION WEDNESDAY BRINGING DRY
AND COLD CONDITIONS. AN ALBERTA CLIPPER AND ITS ASSOCIATED COLD
FRONT WILL PASS THROUGH WEDNESDAY NIGHT INTO THURSDAY. BITTERLY
COLD CONDITIONS ARE EXPECTED BEHIND THIS SYSTEM THROUGH THE END OF
THE WEEK AND FIRST PART OF THE WEEKEND. ANOTHER SYSTEM MAY AFFECT
THE REGION ON SUNDAY.
&&
.NEAR TERM /TODAY/...
SVRL SIDEBARS TO START THIS DSCN...
1) MEGA KUDOS TO THE LONG RANGE MDLS WHICH PROGGED THIS COLD WV 7 DAYS AGO.
ONE THING INTERESTING DURG MY CAREER HAS BEEN TO WITNESS HOW MUCH
FARTHER INTO THE FUTURE MDLS CAN GO AND HOW MUCH MORE ACCURATE
THESE ARE.
2) I`D GUESS EVERYONE KNOWS IT`S GOING TO BE QUITE COLD TDA THRU
THE WKND. RATHER THAN REINVENT THE WHEEL I`VE LEFT THE CLIMO SXN
WRITTEN BY THE EVE SHIFT BLO. BUT WHILE IT WL CERTAINLY BE COLD THIS
DOES NOT LOOK TO BE EVEN CLOSE TO RECORD BREAKING. DID A SEARCH ON
LOW TEMPS AT THE THREE MAJOR AIRPORTS 1989-2009. AT IAD ALL TEN
LOWEST ARE SUB-ZERO...BUT NONE IN THE 2000`S. 12/7/02 WAS #12 WHEN
+1 WAS OBSERVED. FOR BWI #11 WAS 1/18/03 WHEN +5 WAS REACHED...AND
DCA HIT +8 ON 1/10/04.
NO RECORD MINS HV BEEN SET IN THE 2000`S AT ANY OF THE THREE MAJOR
AIRPORTS IN JAN OR FEB...BUT QUITE A FEW RECORD HIGH MINS HV.
AND NOW...BACK TO TDA. HIGH PRES WL QUICKLY BUILD INTO THE RGN.
RCVD A REPORT ARND 1130 THAT SNOW IN FROSTBURG WAS FALLING
LGTLY...AND THAT SHOULD BE GETTING CLOSE TO THE END. NATL COMP RDR
SHOWS ONLY A THIN STREAMER FM WRN LAKE ERIE. SHORT TERM MDLS SHOW
THE SNOW COMING TO AN END B4 SUNRISE...SO WL LET THE WINT WX
ADVSRY EXPIRE AT 4 AM. ALSO INTERESTING - IR STLT SHOWS ICE OVR
WRN LAKE ERIE...WHICH IS CORROBORATED BY THE NOAA GRT LKS
COMPOSITE GRAPHIC..WHICH ON 8 JAN SHOWED 8/10 CVRG. THE MORE ICE
THAT FORMS THE LESS MOISTURE AVBL FOR UPSLOPE IN THE HIGHLANDS?
IT`S BRZY ATTM...BUT THAT TOO SHOULD COME QUICKLY TO AN END AS THE
HIGH MOVES OVR THE MID ATLC RGN.
PLENTY OF SUNSHINE E OF THE MTNS TDA. HIGHS ONLY 30-35 E OF THE
MTNS...25-30 W.
&&
.SHORT TERM /TONIGHT/...
LOW PRES CURRENTLY NEAR OMAHA WL TRACK RAPIDLY E ON A 120 KT JET.
MAJORITY OF SNSH W/ THIS WL TRACK N OF THE CWA. WE ARE CURRENTLY
ADVSRTSG LO POPS IN DC METRO AFTR MDNGT WHICH CERTAINLY COULD
OCCUR..BUT THIS SYSTEM WL TRACK QUICKLY THRU SO NO ACCUM IS XPCTD.
1/2-1" PSBL IN HIGHLANDS. FOR NOW WL LV THE PSBLTY OF ANOTHER LOW
END ADVSRY THERE TO THE DAYSHIFT.
TEMPS LM20S E OF MTNS. TEENS W.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
WINTER COLD HAS DEFINITELY SETTLED INTO THE MID ATLC. FOR EXAMPLE...
IN DC PROPER IT LIKELY WON/T GET ABOVE FREEZING UNTIL SUNDAY...AND
ONLY FOR A FEW HRS DURING THE AFTN. TWO STRAIGHT NIGHTS OF SUBZERO
AND SINGLE DIGIT WIND CHILLS ARE CLOSE AT HAND. ARCTIC AIR WILL
INVADE THE REGION EAST OF APLCNS AFTER A WINDY DAY ON THURS. AFTER
THE ARCTIC COLD FRONT SLIDES ACROSS THE AREA EARLY THURS MRNG /AND
DWPTS DROP INTO THE SINGLE DIGITS/ TEMPS WILL PLUMMET THRU THE REST
OF THE AFTN/EVNG HRS. BY LATE EVNG...TEMPS WILL ALREADY BE IN THE
UPPER TEENS ACROSS THE I-95 CORRIDOR. LOWS WILL BOTTOM OUT IN THE
LOWER TEENS FOR THE METRO AREA...SINGLE DIGITS FOR MUCH OF THE CNTRL
AND WRN PORTIONS OF THE CWA...AND A FEW SUBZERO MARKS ACROSS THE
HIGHER ELEVATIONS. THE BIGGER ISSUE W/ THIS IS THAT WINDS WILL STILL
BE SUBSIDING FROM A BREEZY AFTN W/ PEAK WIND GUSTS IN THE 30-35 MPH
RANGE.
BY LATE EVNG...SFC WINDS WILL STILL BE GUSTING INTO THE 15-20 MPH
RANGE FOR MUCH OF THE AREA. OVERNIGHT...OVERALL WIND SPEEDS WILL
DROP INTO THE 5-10 MPH RANGE...BUT WELL INTO THE OVERNIGHT HRS.
WIND CHILL PRODUCTS MAY BE WARRANTED...MAINLY WEST OF THE VA BLUE
RIDGE. EAST OF THE BLUE RIDGE...WINDS SHOULD BE LIGHT ENOUGH BY
THE TIME TEMPS DROP INTO THE LOWER TEENS. IF GUIDANCE SUGGESTS WINDS
WILL DECREASE QUICKER THAN CURRENT SOLUTIONS SUGGEST...MUCH LESS
AREA MAY NEED TO BE COVERED THO AMBIENT TEMPS WILL BE DANGEROUS
ENOUGH THAT THE PUBLIC SHOULD AT VERY LEAST BE WARY OF THE COLDEST
AIR OF THE SEASON WILL BE UPON US. HIGHS ON FRI BARELY OUT OF THE
TEENS...POSSIBLY BREACHING 20 DEGREES EAST OF I-95...A FEW SINGLE
DIGITS READING FOR HIGHS ACROSS EXTREME WRN PANHANDLE REGIONS OF WV.
SAME STORY FRIDAY NIGHT...JUST A BIT COLDER AND LESS WINDY. WITH
EVEN DRIER AIR /DWPTS WELL BELOW ZERO/ AS THE CENTER OF A STRONG
SFC HIGH PASSES OVER THE REGION...AMBIENT TEMPS WILL DROP INTO AT
LEAST SINGLE DIGITS FOR MUCH OF THE OHIO VLY ALL THE WAY TO THE
ATLC COAST. NO WIND CHILL PRODUCTS ANTICIPATED FOR OVERNIGHT FRI
W/ WINDS LIGHT/VRB.
BY THE END OF THE WEEK...THE LONGWAVE TROF WILL BE POSITIONED A BIT
FURTHER EAST...MAKING THE ARCTIC BLASTS ALSO DISPLACED FURTHER EAST
AS THE SLIDE SE ACROSS THE SRN END OF HUDSON BAY.
SAT...ANOTHER SERIES OF WEAK UPPER VORTS WILL SLIDE THRU THE GRT
LKS REGION. A SFC LOW LOOKS TO INITIALLY MAKE A FAST APPROACH
TOWARD THE CNTRL APLCNS FROM THE NW...BUT DISSIPATES OVER LAKE
ERIE AS A SECONDARY UPPER WAVE PUSHES DUE SOUTH INTO THE UPPER
MIDWEST LATE SAT. SLY WINDS WILL INCREASE UP THE ERN SEABOARD LATE
SAT...ADDING A BIT MORE LOW LEVEL MOISTURE A MAKING IT FEEL A BIT
LESS MISERABLE GOING INTO SUNDAY.
THE BEST CHANCE FOR AT LEAST LOW CHANCE SNOW PROBABILITIES LOOKS
TO BE SUNDAY AS THE LOW WASHES OUT AND THE INCOMING DYNAMICS OF
THE UPPER TROF PUSH THE DISSIPATING FRONT ACROSS THE REGION. THE
00Z EUROPEAN DOESN/T DISSIPATE THE LOW AND INSTEAD DEVELOPS A
NOR`EASTER FOR THE NEW ENGLAND STATES SUNDAY INTO EARLY MON...AN
UNLIKELY SCENARIO AT THIS TIME.
THEN...ONE AFTER ANOTHER...UPPER WAVES SLIDES DOWN THE SAME PATH
OVER THE GRT LKS REGION THRU THE MIDDLE OF NEXT WEEK. EACH ONE W/
AT LEAST A LOW CHANCE OF A FEW FLURRIES OR SCATTERED SNOW BANDS.
TUESDAY OF NEXT WEEK /AT THIS TIME/ SHOWS MODELS BACKING OFF FROM
EVEN LOW CHANCE SNOWS AS IT LOOKS LIKE A TRANSITION DAY FROM ONE OF
THE WEAK LOW PRESSURE SYSTEMS EXITING THE REGION OFF THE ATLC COAST.
TUE A TRANSITION DAY MEANING TEMPS STILL IN THE 20S DURING THE
MRNG HRS...WINDS GRADUALLY INCREASING DURING THE LATE MRNG AND
HIGHS JUST ABOVE FREEZING. MOS GUIDANCE HAS EVEN BACKED OFF ON
CLOUD COVER...FOR A MOSTLY SUNNY AFTN. ALL THIS LOOKS TO HINGE ON
THE TIMING AND PROGRESS OF ONE OF THESE UPPER VORTS THAT...FOR
EXAMPLE THE GFS PUSHES DOWN INTO THE DEEP SOUTH ON TUES...WHICH
WOULD BE A DRY SOLUTION FOR THE MID ATLC.
&&
.AVIATION /TODAY THROUGH SUNDAY/...
BRZY CONDITIONS ATTM WL SUBSIDE THIS MRNG. VFR CONDS TDA/TNGT.
A COLD FRONT WILL SLIDE ACROSS THE REGION DURING THE MID MRNG HRS
THURSDAY...W/ W-NWLY WINDS QUICKLY PICKING UP BEHIND THE BOUNDARY.
SFC WINDS EXPECTED TO GUST 20-30KT...W/ A 40-50KT LL JET SLIDING
ACROSS THE REGION DURING THE AFTN. WEAKER GUSTS ON FRI AFTN...THEN
LITTLE CONCERN THRU EARLY NEXT WEEK OTHER THAN VERY COLD TEMPS.
&&
.MARINE...
IN SHORT TERM IN REALITY TWO SCA`S SURROUNDED BY A PD OF WINDS BLO
SCA VALUES. CD AIR RUSHING INTO AREA THIS MRNG IS PRODUCING WIND
GUSTS OF 25-30 KTS. THESE LOOK TO SLACKEN THIS AFTN AND THIS
EVE...TO INCRS AFTR MDNGT WHEN ALBERTA CLIPPER PUSHES OFF THE CST.
A LOW PRESSURE SYSTEM SLIDING INTO THE REGION OVERNIGHT WED INTO THE
EARLY MRNG HRS THURS. GUSTY WINDS WILL BRIEFLY PEAK NEAR GALE OVER
SRN/CNTRL PORTIONS OF THE BAY MIDDAY THURS...BUT MAINLY SOLID SCA
CONDITIONS OVER THE WATERS ALL-DAY THURSDAY. LESSER CONCERNS FOR
FRIDAY AFTN...AND FAIRLY LIGHT WINDS OVER THE WATER FOR THE COMING
WEEKEND.
&&
.CLIMATE...
VERY COLD WEATHER EXPECTED THIS FRIDAY /16 JAN/ INTO SATURDAY
MORNING /17 JAN/. HOWEVER...SINCE THIS IS NEAR THE CLIMATOLOGICALLY
COLDEST TIME OF YEAR...RECORD LOWS AND/OR RECORD LOW MAXIMUM
TEMPERATURES APPEAR UNLIKELY IN THE IMMEDIATE BALTIMORE/WASHINGTON
METROPOLITAN AREA. STILL...IT DOES LOOK TO BE THE COLDEST AIRMASS
FOR THE AREA IN OVER A DECADE. IT WAS NOTABLY COLDER FOR A FEW DAYS
IN MID JANUARY 1994 AT BWI/DCA/IAD.
BELOW ARE THE FORECAST MAXIMA FOR FRIDAY AND THE FORECAST MINIMA FOR
SATURDAY WITH THE MOST RECENT TIMES TEMPERATURES NEARED THESE
LEVELS...AS WELL AS RECORD LOWEST MAX ON 16 JAN AND RECORD LOW ON 17
JAN.
BWI...FRI FCST HIGH: 18 F /HIGHS OF 5-18 F IN MID JAN 1994 AND 19 F
ON JAN 10 2004 AND FEB 4 1996...RECORD LOW MAXIMUM OF 14 F IN 1893/
DCA...FRI JAN 16 FCST HIGH: 20 F /HIGH OF 17 F ON FEB 4 1996 AND 20
F ON FEB 3 1996 AND 21 F ON JAN 10 2004...RECORD LOW MAXIMUM OF 15 F
IN 1893/
IAD...FRI FCST HIGH: 18 F /HIGH OF 14 F ON FEB 4 1996 AND 19 F ON
JAN 17-18 1997 AND 20 ON FEB 5 2007...RECORD LOW MAXIMUM OF 14 IN
1972 AND 1996/
BWI...SAT FCST LOW: 1 F /LOW OF -1 F ON FEB 5 1996 AND 1 F ON JAN 19
1997...RECORD LOW OF -7 IN 1982/
DCA...SAT FCST LOW: 4 F /LOW OF 5 F ON FEB 5 1996...RECORD LOW OF -5
IN 1982/
IAD...SAT FCST LOW: 1 F /LOW OF -1 F ON FEB 7 1995...RECORD LOW OF
-7 IN 1982/
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST THURSDAY FOR ANZ530>537.
&&
$$
PRODUCTS...WOODY!/GMS
CLIMATE...BAJ/JRK/MRK
000
FXUS61 KAKQ 140826
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
326 AM EST WED JAN 14 2009
.SYNOPSIS...
HIGH PRESSURE BRIEFLY BUILDS INTO THE MID ATLANTIC REGION FROM
THE SOUTHWEST TODAY. A STRONG COLD FRONT CROSSES THE REGION
THURSDAY...FOLLOWED BY ARCTIC HIGH PRESSURE AND VERY COLD AIR FOR
THURSDAY NIGHT INTO SATURDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
THE 1ST PHASE OF THE ARCTIC INVASION TAKES PLC TDA. GSTY NNW WNDS
USHERING IN COLDER/DRY AMS ATTM...WNDSPDS STAY UP THROUGH THE MRNG
HRS B4 DCRSG AS WK SFC HI PRES NOSES INTO RGN FM THE SW. ALREADY
WL BE LOOKING WWD FOR NEXT CLIPPER SYS APPROACHING FM THE NW WHICH
SPRDS SCT/BKN CLDNS INTO FA BY LT AFTN HRS. HI TEMPS FM THE L30S
TO L40S...W/ DWPTS DROPPING INTO THE SINGLE DIGITS/TEENS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/...
LLVL FLO SWINGS TO SW...AND INCRSS OVRNGT. AFT QUIK TEMP DROP
(ERY) THIS EVE...RDGS LVL OFF FOR THE REST OF THE NGT. SFC LO PRES
TRACKS BY JUST N OF RGN...W/ TRAILING (STRNG) CDFNT TO THE CST BY
12Z/15. STRNG LLVL CAA TO FOLLOW DURG THU...TEMPS NOT LIKELY TO
RISE TO MUCH FM MRNG RDGS (HI TEMPS MNLY M30S TO M40S). ANOTHER
RND OF GSTY NNW WNDS (LT TNGT/THU)...RESULTS IN WND CHILLS IN THE
TEENS/20S.
MUCH COLDER/XTRMLY DRY THU NGT/FRI...UNDER GENLY SKC. DWPTS MSTLY
FM 5 BLO ZERO TO 5 ABV ZERO. LO TEMPS THU NGT IN THE TEENS TO
L20S...HI TEMPS FRI STRUGGLE TO REACH THE U20S/ARND 30 DESPITE
SUNSHINE.
CNTR OF ARCTIC SFC HI PRES MVS OVR FA FRI NGT...SETTING UP COLDEST
NGT OF WINTER THUS FAR. RDGS FALL DN INTO THE SINGLE DIGITS ABV
ZERO IN MANY INLAND LCTNS...MSTLY TEENS ELSW (AND THIS IS W/O ANY
SNWCVR).
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
TEMPS START TO MODERATE (ALBEIT SLOLY) ON SAT AS THE FLOW BECOMES
SW WITH THE HIGH SLIDING OFFSHORE. HIGHS `WARM` SAT INTO THE LWR
TO MID 30S. LOWS "MILDER" SAT NIGHT...NEAR 20 NW TO NEAR 30 SE.
SEVERAL TROFS/AREAS OF LOW PRES WILL THEN ROTATE THRU THE MID-
ATLANTIC FROM SUN THRU EARLY NEXT WEEK. FCST MODEL SOUNDINGS SHOW
PLENTY OF DRY AIR IN PLACE AS EACH TROF MOVES THRU...AND GIVEN THE
TRAJECTORY OF EACH WAVE EXPECT THAT IT WILL BE DIFFICULT TO GET MUCH
IF ANY MEASURABLE PRECIP OUT OF THESE FEATURES. IF MODELS START TO
TREND WITH A TRACK FARTHER TO THE S THEN WILL NEED TO INCREASE THE
CHANCE OF PRECIP. WILL KEEP POPS CAPPED BETWEEN 20-30% AT THIS TIME.
AT ANY RATE...COLD AIR WILL REMAIN IN PLACE THRU AT LEAST EARLY NEXT
WEEK (ALTHO NOT AS COLD AS FRI-SAT). HIGHS WILL BE IN THE UPR 30S
NW/N TO MID 40S SE...LOWS IN THE LWR 20S NW/N TO NEAR 30 SE.
&&
.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
QUIET WX AND VFR CONDITIONS WILL PREVAIL DURING THE NEXT SEVERAL
DAYS. WINDS WILL BE GUSTY AT TIMES THU AS AN ARCTIC COLD FRONT
CROSSES THE AREA. THEN A LOW PRESSURE SYSTEM MAY IMPACT THE AREA SUN
WITH A CHANCE OF PRECIPITATION AND POSSIBLY LOWERING AVIATION
CONDITIONS.
&&
.MARINE...
MARGINAL GALE FOR THE NRN COASTAL WTRS WILL CONT THRU THIS MORNING.
COLDER AIR IS JUST ABOUT THE REACH THE COASTAL WATERS WHERE GUSTS
AROUND 35 KT CUD REACH THE SFC. OTHERWISE...SCA`S UP FOR THE REST OF
THE WATERS UNTIL LATE MORN/EARLY AFTN.
WATERS CAN EXPECT A BRIEF RESPITE THIS AFTN AND EARLY EVENING AS
HIGH PRES BRIEFLY BUILDS IN. THEN SOUTHERLY WINDS BEGIN PICKING UP
ONCE AGAIN LATER TONIGHT. EXPECT YET EVEN COLDER AIR WITH THIS
FROPA...AND THINK THAT MODELS ARE SERIOUSLY UNDERDOING THE WINDS W/
THIS NEXT EVENT. CERTAINLY LOOKING AT HIGH END SCA`S FOR LATER
TONIGHT INTO EARLY THU...BUT ALSO POSSIBLY LO-END GALES. WILL ALLOW
DAY SHIFT TO MAKE DECISION...ONCE CURRENT HEADLINES HV EXPIRED.
&&
.CLIMATE...
VERY COLD WEATHER EXPECTED ON FRIDAY (THE 16TH) INTO THE MORNING OF
SAT (THE 17TH)...BUT SINCE THIS IS CLIMATOLOGICALLY RIGHT AROUND THE
COLDEST TIME OF YEAR...RECORD LOWS AND/OR RECORD LOW MAX
TEMPERATURES APPEAR UNLIKELY AT THE MAIN CLIMATE SITES
(RICHMOND/NORFOLK/SALISBURY). STILL...IT DOES LOOK TO BE THE COLDEST
CONDITIONS WE HAVE EXPERIENCED IN A FEW YEARS:
FCST HIGH FOR FRIDAY:
RICHMOND.....FRI FCST HIGH: 28 F (LAST TIME HIGH WAS COLDER THAN
30 F OCCURRED FEB 6TH 2007)
NORFOLK......FRI FCST HIGH: 30 F (LAST TIME HIGH WAS COLDER THAN
30 F OCCURRED JAN 28TH 2005)
SALISBURY....FRI FCST HIGH: 25 F (LAST TIME HIGH WAS COLDER THAN
25 F OCCURRED FEB 6TH 2007).
REC LOWS SAT JAN 17TH...
RIC... -1 (1977)
ORF... 5 (1977)
SBY... -6 (1965)
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR
ANZ630>633-656-658.
GALE WARNING UNTIL 7 AM EST THIS MORNING FOR ANZ650-652-654.
&&
$$
SYNOPSIS...ALB/MPR
NEAR TERM...ALB
SHORT TERM...ALB
LONG TERM...ALB/JRL
AVIATION...SMF
MARINE...SMF
CLIMATE...AKQ
000
FXUS61 KRNK 140538
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
1238 AM EST WED JAN 14 2009
.SYNOPSIS...
A COLD FRONT WILL MOVE OFF THE VIRGINIA COAST OVERNIGHT. WEAK
HIGH PRESSURE WILL BUILD IN BRIEFLY WEDNESDAY. AN ARCTIC COLD
FRONT WILL CROSS THE AREA LATE WEDNESDAY NIGHT AND THURSDAY.
&&
.NEAR TERM /THROUGH TODAY/...
COLD FRONT IS NOW EAST OF ROANOKE...AND WILL CLEAR THE FORECAST
AREA AFTER MIDNIGHT. SNOW SHOWERS IN THE MTNS HAVE TRANSITIONED TO
MAINLY UPSLOPE ON THE WESTERN SLOPES...BUT UPSTREAM RADARS SHOW
NUMEROUS SNOW SHOWERS STILL HEADED THIS WAY...SO I HAVE EXTENDED
THE HIGHER POPS THROUGH 400 AM- ESPECIALLY UPSLOPE AREAS OF SE WV
AS NW TRAJECTORIES CONTINUE THERE THRU MUCH OF THE NIGHT. TEMPS
HAVE DROPPED OFF FAIRLY QUICKLY BEHIND THE COLD FRONT IN THE MTNS.
00Z SOUNDINGS SUPPORT THE 18Z MODEL DATA SHOWING -16C AT 850 MBS
MOVING INTO THE MTNS. I HAVE LOWERED THE OVERNIGHT MINS A FEW
DEGREES FROM THE BLUE RIDGE WEST. MOST MTN LOCATIONS WILL DROP
INTO THE TEENS. STILL DOES NOT LOOK LIKE ENOUGH SNOW FOR AN
ADVISORY- GENERALLY 1 TO 2 INCHES...EXCEPT FOR WESTERN
GREENBRIER...WHICH I HAVE RAISED TO 3-4 INCHES. WILL CONTINUE TO
HANDLE WITH SPS- WITH TEMPS DROPPING SO COLD...UNTREATED ROADS
WILL KEEP SOME SNOW COVER.
THE WINDS BEHIND THE FRONT ARE NEAR THEIR PEAK NOW- GUSTING TO
AROUND 40 MPH IN THE NC MTNS. STILL DO NOT EXPECT ADVISORY LEVEL
WINDS. AS THE HIGH BUILDS INTO THE AREA WED...WINDS WILL BECOME
LIGHT. THERE WILL BE A FEW HOUR PERIOD OF WIND CHILLS AROUND
5 BELOW ZERO OVER THE MTNS OF SE WV AND ELEVATIONS ABOVE 3500 FEET
IN THE NC MTNS TOWARD DAWN. NOT ENOUGH COVERAGE TO WARRANT A WIND
CHILL ADVISORY. HAVE KEPT THE HIGHLIGHT OF THE SNOW AND WIND CHILLS
IN THE HAZARDOUS WEATHER OUTLOOK.
FOR WED...SHOULD SEE PLENTY OF SUN MOST AREAS...WITH FLOW BECOMING
SW AHEAD OF THE ARCTIC BLAST. WENT GENERALLY WITH MAV MOS FOR
HIGHS. WINDS WILL START TO INCREASE OVER THE SW VA/NW NC MTNS
TOWARD THE LATE AFTERNOON AS 40+ KNOT SW 8H JET PUSHES IN AHEAD OF
FRONT. CLOUDS INCREASE LATE IN THE DAY FROM THE NORTHWEST...BUT
ANY PRECIP WILL HOLD OFF UNTIL WED NIGHT.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
ARCTIC FRONT TO CROSS WEDNESDAY NIGHT WITH THE COLDEST AIR THIS
WINTER. AREA OF LOW PRESSURE TAKES A FAVORABLE TRACK FOR AT LEAST
WIND ADVISORY CRITERIA/HIGH WIND WATCH GUSTS AT THE VERY LEAST
ACROSS SW VA AND NW NC. UNIDIRECTIONAL WINDS...AND THE JET
DIRECTORY OVERHEAD OF ASHE/WATAUGA/GRAYSON...ALONG WITH AN
IMPRESSIVE ISENT OMEGA RISE/FALL COUPLET MAY PRODUCE WIND GUSTS
STRONGER THAN EVEN BUFKIT IS FORECASTING RIGHT NOW. WOULD LIKE TO
SEE MORE DOWNGLIDE FROM AN ISENTROPIC PERSPECTIVE THOUGH. AN EVENT
SIMILAR TO THIS WAS UNDER FORECASTED BY THE MODELS A FEW WEEKS AGO.
AFTER COORD WITH GSP...DECIDED NOT TO HOIST A HIGH WIND WATCH BUT
THIS NEEDS TO BE CONSIDERED LATER FOR WED NIGHT THROUGH THUR
AFTERNOON...BUT MOST LIKELY WHEN THE ARCTIC CROSSES NEAR DAWN
THURSDAY. MIDLEVEL LAPSE RATES AND STRENGTH OF FRONT INDICATE SOME
SNOW SQUALLS POSSIBLY ALONG THE FRONT ACROSS SE WEST VA LATER
WEDNESDAY NIGHT...WITH A QUICK INCH OR TWO ALONG THE FAVORED
SPOTS. ANOTHER INCH OR TWO COULD FALL THURSDAY. ALTHOUGH
FAVORABLE UPSLOPE CONDITIONS WANE THURSDAY...A SHRTWV DROPPING
INTO THE CWA MAY PROVIDE ANOTHER SHOT OF SNOW INTO THE BLUE RIDGE
ON THURSDAY AFTERNOON. SEEMS AS THE 12Z MEX IS FINALLY REALIZING
THE STRENGTH OF THIS AIRMASS...SO GENERALLY FOLLOWED IT ON DAY
4...WHILE UNDERCUTTING MOS LEADING UP TO THAT POINT WITH THE
SHALLOW ARCTIC AIR. A WIND CHILL ADVISORY WILL ALSO BE NEEDED
PERHAPS AS EARLY AS WEDNESDAY NIGHT. IF NO HIGH CLOUDS ARRIVE
FRIDAY NIGHT...AND MOST SPOTS ARE ABLE TO DECOUPLE...AOB 0F IS
POSSIBLE ALONG THE BLUE RIDGE AND INTO SE WEST VA WITH STRONG HIGH
OVERHEAD.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ARCTIC DOME OF HIGH PRESSURE WILL BE LOCATED ACROSS OUR REGION
SATURDAY MORNING WITH VERY COLD READINGS IN THE SINGLE DIGITS TO
LOWER TEENS. AREAS WITH ANY SNOW COVER COULD SEE SUBZERO SINGLE
DIGIT LOWS...EVERYONE ELSE SHOULD STAY ON THE PLUS SIDE OF ZERO.
HIGH PRESSURE WILL SLIDE EAST ON SATURDAY. TEMPERATURES SHOULD
GRADUALLY MODERATE SATURDAY AFTERNOON INTO SUNDAY AHEAD OF ANOTHER
CONTINENTAL FRONT THAT WILL CROSS THE FORECAST AREA. CONTINUED THE
CHANCE OF SNOW WITH ITS PASSAGE SATURDAY NIGHT INTO SUNDAY. KEPT
LIGHT CHC POPS IN THE WESTERN MOUNTAINS SUNDAY NIGHT INTO MONDAY.
NEXT FRONT ARRIVES ON TUESDAY WITH CHANCE FOR RAIN AND SNOW. LEANED
EARLY NEXT WEEK TOWARDS THE ECMWF WITH ADDITIONAL CLOUDS AND
POPS...WHICH DIVES SYSTEM FURTHER SOUTH WITH COASTAL LOW DEVELOPMENT
COMPARED TO GFS. PLAYED TEMPERATURES CLOSE TO HPCGUIDE.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
A COLD FRONT WILL TRAVEL EAST OFF THE COAST TONIGHT. MVFR/IFR
CIGS IN SNOW SHOWERS IN THE MOUNTAINS WILL GRADUALLY DIMINISH BY
09Z. ELSEWHERE...VFR CONDITIONS ARE EXPECTED. WINDS GUSTS WILL
ALSO DIMINISH AS LOW LEVEL WINDS BACK AHEAD OF THE NEST
APPROACHING SHORT WAVE.
CONDITIONS WILL REMAIN MVFR AT BLF/LWB THROUGH DAYBREAK BEFORE DRIER
AIR SCATTERS OUT THE CEILINGS. ELSEWHERE...LOOK FOR VFR CIGS
OVERNIGHT THEN CLEARING.
A STRONGER ARCTIC COLD FRONT WILL CROSS THE AREA WEDNESDAY NIGHT
WITH MVFR CIGS/VSBYS AND SNOW SHOWERS AGAIN IN THE MOUNTAINS
THROUGH THURSDAY MORNING. ALSO STRONG WINDS AT HIGHER ELEVATIONS
ARE EXPECTED THROUGH THURSDAY. ANOTHER STORM ARRIVES SATURDAY
NIGHT INTO SUNDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS/WP
NEAR TERM...JJ/WP
SHORT TERM...KM
LONG TERM...KK
AVIATION...AMS/KK/WP
000
FXUS61 KLWX 140325 AAC
AFDLWX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1025 PM EST TUE JAN 13 2009
.SYNOPSIS...
A COLD FRONT WILL CONTINUE TO MOVE THROUGH THE REGION TONIGHT.
HIGH PRESSURE WILL BUILD OVER THE REGION WEDNESDAY BRINGING DRY
AND COLD CONDITIONS. AN ALBERTA CLIPPER AND ITS ASSOCIATED COLD
FRONT WILL PASS THROUGH WEDNESDAY NIGHT INTO THURSDAY. BITTERLY
COLD CONDITIONS ARE EXPECTED BEHIND THIS SYSTEM THROUGH THE END OF
THE WEEK AND FIRST PART OF THE WEEKEND. ANOTHER SYSTEM MAY AFFECT
THE REGION ON SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
COLD FRONT CONTINUING TO QUICKLY ADVANCE EAST ACROSS THE CWA. IN
WAKE OF FROPA...SCATTERED FLURRIES AND SNOW SHOWERS ARE BREAKING
OUT OVER E PANHANDLE OF WV/N VA/N MD. HAVE UPDATED POP/WX GRIDS
ACCORDINGLY TO MENTION SCT/ISO SNSH N AND W OF DC. UPSLOPE SNOW
SHOWERS WILL CONTINUE OVERNIGHT ACROSS THE FAVORED WESTERN SLOPES
OF THE HIGHLANDS. UP TO 1.5 INCHES HAS ALREADY BEEN REPORTED
ACROSS THIS AREA AND AN ADDITIONAL INCH OR SO IS EXPECTED THROUGH
THE REST OF TONIGHT.
TWEAKED HOURLY TEMPS A LITTLE BIT AS PREVIOUS FCST WAS TOO QUICK TO
BRING IN THE COLD AIR. WINDS WILL BE GUSTY BEHIND THE FRONT WITH 20
TO 30 KTS GUSTS EXPECTED THROUGH THE EARLY MORNING HOURS. WINDS
SHOULD BEGIN TO DIMINISH DURING THE MORNING AS HIPRES BUILDS INTO
THE AREA.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH 6 PM WEDNESDAY/...
HIGH PRESSURE BUILDS INTO THE MID ATLANTIC ON WEDNESDAY...BUT ONLY
MAKES A BRIEF APPEARANCE AND IS ALREADY MOVING OFF THE COAST IN
THE AFTERNOON. SNOW SHOWERS IN FAVORED WESTERN UPSLOPE AREAS WILL
CUT OFF EARLY IN THE MORNING. SOME SUNSHINE WILL BE SEEN IN THE
MORNING BUT WILL BE FOLLOWED BY INCREASING CLOUDS IN THE AFTERNOON
AHEAD OF ANOTHER CLIPPER SYSTEM ACROSS THE OHIO VALLEY THAT WILL
MOVE THROUGH AND AFFECT OUR CWA LATER WEDNESDAY NIGHT INTO
THURSDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
AN UPPER-LEVEL LOW OVER EASTERN CANADA WILL REMAIN IN PLACE THROUGH
THE FORECAST PERIOD. THIS WILL CARVE OUT A POTENT MID-LEVEL TROUGH
OVER THE MID-ATLANTIC BRINGING COLD CONDITIONS. SEVERAL DISTURBANCES
WILL ROTATE AROUND THE TROUGH BRINGING CHANCES FOR LIGHT
PRECIPITATION. THE EXACT TIMING AND TRACK OF THESE SYSTEMS REMAINS
UNCERTAIN THIS FAR OUT.
AN ALBERTA CLIPPER WILL PASS THROUGH NORTHERN MARYLAND OVERNIGHT
WEDNESDAY AND THEN QUICKLY OFF THE MID-ATLANTIC COAST THURSDAY. THE
BEST CHANCE FOR SNOW WILL BE ACROSS THE POTOMAC HIGHLANDS...EASTERN
PANHANDLE OF WEST VIRGINIA...AND NEAR THE MASON DIXON LINE. HAVE
KEPT THE HIGHEST POPS AND ACCUMULATING SNOW NEAR THE ALLEGHENY FRONT
WHERE UPSLOPE SNOW WITH THIS SYSTEM IS ALSO EXPECTED. ARCTIC HIGH
PRESSURE WILL APPROACH THE REGION FROM THE NORTHERN PLAINS BEHIND
THIS SYSTEM THURSDAY ALLOWING FOR BITTERLY COLD CONDITIONS BY
THURSDAY NIGHT. LATEST GUIDANCE CONTINUES TO INDICATE LIMITED
INSTABILITY THURSDAY INTO THURSDAY NIGHT BEHIND THE CLIPPER DUE TO
THE STRONG COLD ADVECTION. WILL CONTINUE WITH CHANCE/SLIGHT CHANCE
FOR SNOW SHOWERS ACROSS THE NORTHERN AND WESTERN PORTION OF THE CWA.
HIGHER POPS NEAR THE ALLEGHENY FRONT. TEMPERATURES THURSDAY NIGHT
AND FRIDAY WILL BE AROUND 20-25 DEGREES BELOW CLIMO. THE NORMAL HIGH
AND LOW FOR WASHINGTON DC IS 42 AND 27 DEGREES RESPECTIVELY.
ARCTIC HIGH PRESSURE WILL MOVE OFF THE MID-ATLANTIC COAST SATURDAY
ALLOWING A RETURN FLOW TO SET UP. TEMPERATURES WILL REMAIN WELL
BELOW NORMAL DESPITE THE RETURN FLOW. ANOTHER UPPER-LEVEL
DISTURBANCE AND ITS ASSOCIATED SURFACE LOW WILL TRACK THROUGH THE
REGION SATURDAY NIGHT INTO SUNDAY BRINGING THE CHANCE FOR
PRECIPITATION. BELOW NORMAL TEMPERATURES WILL CONTINUE MONDAY BEHIND
THIS SYSTEM.
BELOW NORMAL TEMPERATURES ARE EXPECTED FOR TUESDAY AS WELL. ANOTHER
DISTURBANCE WILL BRINGING THE CHANCE FOR SNOW. THE EXACT TIMING AND
TRACK OF THIS DISTURBANCE REMAINS UNCERTAIN THIS FAR OUT.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
A COLD FRONT WILL CONTINUE TO MOVE ACROSS THE TERMINALS FROM W TO
E BY 04Z. WINDS WILL SHIFT TO THE W/NW AND BECOMING GUSTY WITH GUSTS
UP TO 30 KTS POSSIBLE. MENTIONED -SN ACROSS MRB TERMINAL EARLY
TONIGHT. ISO FLURRIES CANNOT BE RULED OUT OVER ALL TERMINALS
EXCEPT DCA AND CHO. VFR CONDITIONS EXPECTED THROUGH TAF PERIOD.
HOWEVER BKN TO SCT MIDLEVEL CIGS EXPECTED TONIGHT. GUSTY WINDS
SHOULD BEGIN TO WEAKEN BY 10-12Z WED BEFORE BECOMING LIGHT AND
VARIABLE LATE WED AFTERNOON AS HIPRES BUILDS INTO THE REGION.
AN AREA OF LOW PRESSURE WILL PASS THROUGH THE TERMINALS OVERNIGHT
WEDNESDAY...THEN OFF THE MID-ATLANTIC COAST THURSDAY. THIS SYSTEM
MAY BRING MVFR CIGS/VSBYS ALONG WITH THE CHANCE FOR LIGHT SNOW
OVERNIGHT WEDNESDAY...ESPECIALLY ACROSS KMRB. GENERALLY VFR
CONDITIONS ARE EXPECTED BEHIND THE SYSTEM THURSDAY...BUT THERE MAY
BE ENOUGH INSTABILITY FOR SCATTERED SNOW SHOWERS ACROSS THE NORTHERN
TERMINALS. GUSTY NORTHWEST WINDS ARE EXPECTED THURSDAY WITH FREQUENT
WIND GUSTS AROUND 30 KNOTS.
HIGH PRESSURE WILL BUILD OVER THE TERMINALS THURSDAY NIGHT THROUGH
FRIDAY NIGHT BRINGING VFR CONDITIONS. A COUPLE DISTURBANCES MAY
AFFECT THE TERMINALS LATER IN THE WEEKEND INTO EARLY NEXT WEEK
BRINGING THE CHANCE FOR PRECIPITATION.
&&
.MARINE...
A COLD FRONT WILL CONTINUE TO MOVE ACROSS THE WATERS BEFORE MIDNIGHT...WITH
WINDS INCREASING BEHIND THE FRONT. ALTHOUGH WINDS ARE LIGHT RIGHT
NOW...SMALL CRAFT CONDITIONS WILL QUICKLY DEVELOP TONIGHT WITH 20
TO 30 KT GUSTS EXPECTED OVERNIGHT. HIGH PRESSURE BUILDS IN
WEDNESDAY...WITH WINDS DIMINISHING TOWARD AFTERNOON.
AN AREA OF LOW PRESSURE WILL PASS THROUGH THE WATERS WEDNESDAY
NIGHT. WINDS MAY APPROACH SMALL CRAFT ADVISORY CRITERIA WITH THIS
LOW...ESPECIALLY LATE. WILL CONTINUE WITH A SMALL CRAFT ADVISORY
WEDNESDAY NIGHT. MUCH STRONGER WINDS ARE EXPECTED BEHIND THIS SYSTEM
THURSDAY WHERE A GALE WARNING MAY BE WARRANTED. WINDS WILL DIMINISH
THURSDAY NIGHT...BUT GUSTS AROUND 20 KNOTS ARE STILL EXPECTED.
HIGH PRESSURE WILL BUILD OVER THE WATERS FOR FRIDAY THROUGH
SATURDAY. THE NEXT DISTURBANCE WILL PASS THROUGH THE WATERS SUNDAY.
&&
.CLIMATE...
VERY COLD WEATHER EXPECTED THIS FRIDAY /16 JAN/ INTO SATURDAY
MORNING /17 JAN/. HOWEVER...SINCE THIS IS NEAR THE CLIMATOLOGICALLY
COLDEST TIME OF YEAR...RECORD LOWS AND/OR RECORD LOW MAXIMUM
TEMPERATURES APPEAR UNLIKELY IN THE IMMEDIATE BALTIMORE/WASHINGTON
METROPOLITAN AREA. STILL...IT DOES LOOK TO BE THE COLDEST AIRMASS
FOR THE AREA IN OVER A DECADE. IT WAS NOTABLY COLDER FOR A FEW DAYS
IN MID JANUARY 1994 AT BWI/DCA/IAD.
BELOW ARE THE FORECAST MAXIMA FOR FRIDAY AND THE FORECAST MINIMA FOR
SATURDAY WITH THE MOST RECENT TIMES TEMPERATURES NEARED THESE
LEVELS...AS WELL AS RECORD LOWEST MAX ON 16 JAN AND RECORD LOW ON 17
JAN.
BWI...FRI FCST HIGH: 18 F /HIGHS OF 5-18 F IN MID JAN 1994 AND 19 F
ON JAN 10 2004 AND FEB 4 1996...RECORD LOW MAXIMUM OF 14 F IN 1893/
DCA...FRI JAN 16 FCST HIGH: 20 F /HIGH OF 17 F ON FEB 4 1996 AND 20
F ON FEB 3 1996 AND 21 F ON JAN 10 2004...RECORD LOW MAXIMUM OF 15 F
IN 1893/
IAD...FRI FCST HIGH: 18 F /HIGH OF 14 F ON FEB 4 1996 AND 19 F ON
JAN 17-18 1997 AND 20 ON FEB 5 2007...RECORD LOW MAXIMUM OF 14 IN
1972 AND 1996/
BWI...SAT FCST LOW: 1 F /LOW OF -1 F ON FEB 5 1996 AND 1 F ON JAN 19
1997...RECORD LOW OF -7 IN 1982/
DCA...SAT FCST LOW: 4 F /LOW OF 5 F ON FEB 5 1996...RECORD LOW OF -5
IN 1982/
IAD...SAT FCST LOW: 1 F /LOW OF -1 F ON FEB 7 1995...RECORD LOW OF
-7 IN 1982/
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...WINTER WEATHER ADVISORY UNTIL 4 AM EST WEDNESDAY FOR MDZ501.
VA...WINTER WEATHER ADVISORY UNTIL 4 AM EST WEDNESDAY FOR VAZ021.
WV...WINTER WEATHER ADVISORY UNTIL 4 AM EST WEDNESDAY FOR WVZ054-
501-503.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST THURSDAY FOR ANZ530>537.
&&
$$
UPDATE...JRK
PREVIOUS DISC...BPP/BJL
000
FXUS61 KAKQ 140301
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
1001 PM EST TUE JAN 13 2009
.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA TONIGHT...AS AN AREA OF LOW
PRESSURE MOVES FURTHER OFF THE MID ATLANTIC COAST. HIGH PRESSURE
BRIEFLY BUILDS IN FROM THE SOUTHWEST ON WEDNESDAY...WITH A STRONG
COLD FRONT CROSSING THE REGION ON THURSDAY. ARCTIC HIGH PRESSURE
WILL USHER IN A COLD AIRMASS FRIDAY INTO SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
CSTL LOW CONTS TO PUSH FRTHR OFSHORE LATE THIS EVE AND ALL PCPN HAS
ENDED ACROSS FA AS OF 02Z. MEANWHILE...CDFRNT CONTS TO MOVE E AND IS
CRNTLY LCTD IVOF THE I95 CORRIDOR. THIS FRNT WILL CONT TO MOVE E AND
PUSH OFFSHORE AFTR 06Z. SAT LOOP AND SFC OBS INDCT A RAPID DRYING
OF COLUMN BEHIND DEPARTING CSTL LOW AS SKIES RPDLY CLR OUT. CAA
SETS IN BEHIND FROPA WITH WNDS BCMG NW AND INCRG IN SPEEDS...SPCLLY
ALONG THE COAST. THUS...LATE EVE UPDATE TO ZFP / GRIDS WILL SHOW
SCT-BKN HIGH LVL CLDS ARND FOR NXT FEW HRS. KEPT SCT RW ACROSS CSTL
WTRS FOR NXT FEW HRS AS WELL. TMPS FALL INTO THE 20S TO NR 30.
QPF WITH TDYS SYSTM RANGED FROM A TRACE UPWARDS TO .20 INCHES ALONG
THE COAST. MEASURABLE RAIN FELL MAINLY E OF A RZZ-AKQ-JGG-SBY LINE.
WITH TMPE XPCTD TO DROP BLO FREEZING BY 12Z WED...WENT AHEAD AND
ISSUED AN SPS FOR AREAS OF BLACK ICE AS ANY LEFT OVR MSTR WILL
LIKELY FREEZE ON RAISED SURFACES.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY NIGHT/...
DRY CONDS START OUT THE DAY ON WEDNESDAY AS THE FRONT CONTINUES TO
PUSH OFFSHORE AND WEAK HIGH PRESSURE BUILDS IN. EVEN WITH CLEAR
SKIES TO START OUT THE DAY...CAA AND INCREASING CLOUDS WILL KEEP MAX
TEMPS DOWN IN THE MID 30S (WEST AND NORTH WHERE THEY`LL SEE CLOUDS
SOONER IN THE DAY) TO AROUND 40 DEGREES IN THE SOUTH/SOUTHEAST
AREAS. ANOTHER FAST MVG SYSTEM MVS TOWARDS THE AREA IN THE AFTN/EVNG
HRS BUT HIGH TO OUR SE WILL KEEP THE LOW TO OUR NORTH. HAVE
CONTINUED ONLY SILENT POPS WITH THIS SYSTEM DUE TO LACK OF MOISTURE
AND THE FACT TAHT MOST OF THE ENERGY REMAINS TO OUR NORTH. SHOULD
STILL SEE PLENTY OF CLOUDS WED NIGHT INTO THURS WITH THIS FEATURE
HOWEVER.
TROUGH MVS OVER THE EAST COAST THURS NIGHT/FRI MORNING...SO A BIG
CHANGE EXPECTED GOING INTO FRIDAY MORNING. CLEARING SKIES THURS
NIGHT ALONG WITH LIGHT WINDS AND STRONG CAA WILL ALLOW TEMPS TO DROP
INTO THE TEENS MOST LOCATIONS. GUIDANCE HAS BEEN TRENDING COLDER AND
THEREFORE HAVE DROPPED MINS A FEW DEGREES FROM PREVIOUS FCST. STRONG
HIGH BUILDS INTO THE OH VALLEY ON FRIDAY...KEEPING MAX TEMPS DOWN
BLO FREEZING AND MOCLEAR SKIES OVER THE AREA.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
HIGH PRES BUILDS IN FROM THE W FRI NIGHT THRU SAT NIGHT. FRIGID LOW
TEMPS WILL CONT FRI NIGHT...ONLY NEAR 10 NW/N TO NEAR 20 SE. TEMPS
START TO MODERATE ON SAT AS THE FLOW BECOMES SW WITH THE HIGH
SLIDING OFFSHORE. HIGHS `WARM` SAT INTO THE LWR TO MID 30S. LOWS
ALSO MILDER SAT NIGHT...NEAR 20 NW TO NEAR 30 SE.
SEVERAL TROFS/AREAS OF LOW PRES WILL THEN ROTATE THRU THE MID-
ATLANTIC FROM SUN THRU EARLY NEXT WEEK. FCST MODEL SOUNDINGS SHOW
PLENTY OF DRY AIR IN PLACE AS EACH TROF MOVES THRU...AND GIVEN THE
TRAJECTORY OF EACH WAVE EXPECT THAT IT WILL BE DIFFICULT TO GET MUCH
IF ANY MEASURABLE PRECIP OUT OF THESE FEATURES. IF MODELS START TO
TREND WITH A TRACK FARTHER TO THE S THEN WILL NEED TO INCREASE THE
CHANCE OF PRECIP. WILL KEEP POPS CAPPED BETWEEN 20-30% AT THIS TIME.
AT ANY RATE...COLD AIR WILL REMAIN IN PLACE THRU AT LEAST EARLY NEXT
WEEK (ALTHO NOT AS COLD AS FRI-SAT). HIGHS WILL BE IN THE UPR 30S
NW/N TO MID 40S SE...LOWS IN THE LWR 20S NW/N TO NEAR 30 SE.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
LOW PRESSURE OFF THE SE VA/NE NC CST...WILL LIFT QUICKLY NE AWAY
FM THE AREA TNGT. LGT RAIN WAS STILL RIGHT ALNG THE CST ARND 745
PM BUT WILL BE MOVNG OUT TO SEA IN THE NEXT COUPLE OF HRS. CIGS
AND VSBYS WILL IMPROVE QUICKLY TO MAINLY VFR CONDS...AND NW WNDS
WILL INCRS OVRNGT...AS HI PRES STARTS TO BLD IN FM THE W.
VFR CONDITIONS WILL PREVAIL DURING THE NEXT SEVERAL DAYS. WINDS
WILL BE GUSTY AT TIMES THU AS AN ARCTIC COLD FRONT CROSSES THE
AREA. A LOW PRESSURE SYSTEM MAY IMPACT THE AREA SUN WITH A CHANCE
OF PRECIPITATION AND POSSIBLY LOWERING AVIATION CONDITIONS.
&&
.MARINE...
AN AREA OF LOW PRES WILL CONTINUE TO DEVELOP/DEEPEN OFF THE NC OBX.
THE LOW WILL MOVE TO THE NE AND AWAY FROM THE COAST TONIGHT...AS A
COLD FRONT SWEEPS IN FROM THE W. WINDS/SEAS WILL INCREASE/BUILD
LATER THIS EVENING...AND SCA FLAGS REMAIN IN EFFECT...BEGINNING AT
03Z TONIGHT. WINDS WILL BE THE STRONGEST OVER THE NRN WATERS COASTAL
WATERS FROM CAPE CHARLES LIGHT VA NORTHWARD...AND HAVE GALE WARNINGS
IN EFFECT FOR THOSE ZONES. ONLY EXPECT ABOUT A 6 HR WINDOW FOR GALE
FORCE WINDS TO OCCUR...FROM MIDNIGHT THRU SUNRISE. AFTERWARD WINDS
WILL START TO DIMINISH AND SEAS WILL SLOWLY SUBSIDE AS HIGH PRES
BRIEFLY BUILDS IN FROM THE W ON WED.
ANOTHER AREA OF LOW PRES WILL MOVE ACROSS THE MID-ATLANTIC FROM THE
W WED NIGHT THRU THU...AND HIGH END SCA TO LOW END GALE CONDITIONS
ARE EXPECTED YET AGAIN. HIGH PRES RETURNS LATE FRI THRU SAT
NIGHT...WITH ANOTHER LOW PRES SYSTEM AFFECTING THE REGION BY THE END
OF THE WEEKEND INTO EARLY NEXT WEEK.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST WEDNESDAY FOR ANZ630>633-
656-658.
GALE WARNING FROM 1 AM TO 7 AM EST WEDNESDAY FOR ANZ650-652-
654.
&&
$$
SYNOPSIS...MPR
NEAR TERM...MPR
SHORT TERM...JYM
LONG TERM...JRL
AVIATION...TMG
MARINE...JRL
000
FXUS61 KLWX 140259 AAB
AFDLWX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
959 PM EST TUE JAN 13 2009
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE REGION THIS EVENING. HIGH
PRESSURE WILL BUILD OVER THE REGION WEDNESDAY BRINGING DRY AND COLD
CONDITIONS. AN ALBERTA CLIPPER AND ITS ASSOCIATED COLD FRONT WILL
PASS THROUGH WEDNESDAY NIGHT INTO THURSDAY. BITTERLY COLD CONDITIONS
ARE EXPECTED BEHIND THIS SYSTEM THROUGH THE END OF THE WEEK AND
FIRST PART OF THE WEEKEND. ANOTHER SYSTEM MAY AFFECT THE REGION ON
SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
COLD FRONT CONTINUING TO QUICKLY ADVANCE EAST ACROSS THE CWA. IN
WAKE OF FROPA...SCATTERED FLURRIES AND SNOW SHOWERS ARE BREAKING
OUT OVER E PANHANDLE OF WV/N VA/N MD. HAVE UPDATED POP/WX GRIDS
ACCORDINGLY TO MENTION SCT/ISO SNSH N AND W OF DC. UPSLOPE SNOW
SHOWERS WILL CONTINUE OVERNIGHT ACROSS THE FAVORED WESTERN SLOPES
OF THE HIGHLANDS. UP TO 1.5 INCHES HAS ALREADY BEEN REPORTED
ACROSS THIS AREA AND AN ADDITIONAL INCH OR SO IS EXPECTED THROUGH
THE REST OF TONIGHT.
TWEAKED HOURLY TEMPS A LITTLE BIT AS PREVIOUS FCST WAS TOO QUICK TO
BRING IN THE COLD AIR. WINDS WILL BE GUSTY BEHIND THE FRONT WITH 20
TO 30 KTS GUSTS EXPECTED THROUGH THE EARLY MORNING HOURS. WINDS
SHOULD BEGIN TO DIMINISH DURING THE MORNING AS HIPRES BUILDS INTO
THE AREA.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH 6 PM WEDNESDAY/...
HIGH PRESSURE BUILDS INTO THE MID ATLANTIC ON WEDNESDAY...BUT ONLY
MAKES A BRIEF APPEARANCE AND IS ALREADY MOVING OFF THE COAST IN
THE AFTERNOON. SNOW SHOWERS IN FAVORED WESTERN UPSLOPE AREAS WILL
CUT OFF EARLY IN THE MORNING. SOME SUNSHINE WILL BE SEEN IN THE
MORNING BUT WILL BE FOLLOWED BY INCREASING CLOUDS IN THE AFTERNOON
AHEAD OF ANOTHER CLIPPER SYSTEM ACROSS THE OHIO VALLEY THAT WILL
MOVE THROUGH AND AFFECT OUR CWA LATER WEDNESDAY NIGHT INTO
THURSDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
AN UPPER-LEVEL LOW OVER EASTERN CANADA WILL REMAIN IN PLACE THROUGH
THE FORECAST PERIOD. THIS WILL CARVE OUT A POTENT MID-LEVEL TROUGH
OVER THE MID-ATLANTIC BRINGING COLD CONDITIONS. SEVERAL DISTURBANCES
WILL ROTATE AROUND THE TROUGH BRINGING CHANCES FOR LIGHT
PRECIPITATION. THE EXACT TIMING AND TRACK OF THESE SYSTEMS REMAINS
UNCERTAIN THIS FAR OUT.
AN ALBERTA CLIPPER WILL PASS THROUGH NORTHERN MARYLAND OVERNIGHT
WEDNESDAY AND THEN QUICKLY OFF THE MID-ATLANTIC COAST THURSDAY. THE
BEST CHANCE FOR SNOW WILL BE ACROSS THE POTOMAC HIGHLANDS...EASTERN
PANHANDLE OF WEST VIRGINIA...AND NEAR THE MASON DIXON LINE. HAVE
KEPT THE HIGHEST POPS AND ACCUMULATING SNOW NEAR THE ALLEGHENY FRONT
WHERE UPSLOPE SNOW WITH THIS SYSTEM IS ALSO EXPECTED. ARCTIC HIGH
PRESSURE WILL APPROACH THE REGION FROM THE NORTHERN PLAINS BEHIND
THIS SYSTEM THURSDAY ALLOWING FOR BITTERLY COLD CONDITIONS BY
THURSDAY NIGHT. LATEST GUIDANCE CONTINUES TO INDICATE LIMITED
INSTABILITY THURSDAY INTO THURSDAY NIGHT BEHIND THE CLIPPER DUE TO
THE STRONG COLD ADVECTION. WILL CONTINUE WITH CHANCE/SLIGHT CHANCE
FOR SNOW SHOWERS ACROSS THE NORTHERN AND WESTERN PORTION OF THE CWA.
HIGHER POPS NEAR THE ALLEGHENY FRONT. TEMPERATURES THURSDAY NIGHT
AND FRIDAY WILL BE AROUND 20-25 DEGREES BELOW CLIMO. THE NORMAL HIGH
AND LOW FOR WASHINGTON DC IS 42 AND 27 DEGREES RESPECTIVELY.
ARCTIC HIGH PRESSURE WILL MOVE OFF THE MID-ATLANTIC COAST SATURDAY
ALLOWING A RETURN FLOW TO SET UP. TEMPERATURES WILL REMAIN WELL
BELOW NORMAL DESPITE THE RETURN FLOW. ANOTHER UPPER-LEVEL
DISTURBANCE AND ITS ASSOCIATED SURFACE LOW WILL TRACK THROUGH THE
REGION SATURDAY NIGHT INTO SUNDAY BRINGING THE CHANCE FOR
PRECIPITATION. BELOW NORMAL TEMPERATURES WILL CONTINUE MONDAY BEHIND
THIS SYSTEM.
BELOW NORMAL TEMPERATURES ARE EXPECTED FOR TUESDAY AS WELL. ANOTHER
DISTURBANCE WILL BRINGING THE CHANCE FOR SNOW. THE EXACT TIMING AND
TRACK OF THIS DISTURBANCE REMAINS UNCERTAIN THIS FAR OUT.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
A COLD FRONT WILL MOVE ACROSS THE TERMINALS THIS EVENING. WINDS WILL
BACK TO THE WEST NORTHWEST AND GUST TO 25 TO 30KT ALONG AND
ESPECIALLY BEHIND THE COLD FRONT. HIGH PRESSURE BUILDS IN FOR
WEDNESDAY.
AN AREA OF LOW PRESSURE WILL PASS THROUGH THE TERMINALS OVERNIGHT
WEDNESDAY...THEN OFF THE MID-ATLANTIC COAST THURSDAY. THIS SYSTEM
MAY BRING MVFR CIGS/VSBYS ALONG WITH THE CHANCE FOR LIGHT SNOW
OVERNIGHT WEDNESDAY...ESPECIALLY ACROSS KMRB. GENERALLY VFR
CONDITIONS ARE EXPECTED BEHIND THE SYSTEM THURSDAY...BUT THERE MAY
BE ENOUGH INSTABILITY FOR SCATTERED SNOW SHOWERS ACROSS THE NORTHERN
TERMINALS. GUSTY NORTHWEST WINDS ARE EXPECTED THURSDAY WITH FREQUENT
WIND GUSTS AROUND 30 KNOTS.
HIGH PRESSURE WILL BUILD OVER THE TERMINALS THURSDAY NIGHT THROUGH
FRIDAY NIGHT BRINGING VFR CONDITIONS. A COUPLE DISTURBANCES MAY
AFFECT THE TERMINALS LATER IN THE WEEKEND INTO EARLY NEXT WEEK
BRINGING THE CHANCE FOR PRECIPITATION.
&&
.MARINE...
AS A COLD FRONT MOVES THROUGH THIS EVENING...WINDS WILL INCREASE.
GUSTS ARE EXPECTED TO REACH STRONG SMALL CRAFT ADVISORY CRITERIA /30
KT/ OVERNIGHT. WILL HAVE TO WATCH THE SLIGHT CHANCE THAT GUSTS REACH
MINIMAL GALE WARNING CRITERIA /35 KT/. HIGH PRESSURE BUILDS IN
WEDNESDAY...WITH LESS WIND TOWARD AFTERNOON.
AN AREA OF LOW PRESSURE WILL PASS THROUGH THE WATERS WEDNESDAY
NIGHT. WINDS MAY APPROACH SMALL CRAFT ADVISORY CRITERIA WITH THIS
LOW...ESPECIALLY LATE. WILL CONTINUE WITH A SMALL CRAFT ADVISORY
WEDNESDAY NIGHT. MUCH STRONGER WINDS ARE EXPECTED BEHIND THIS SYSTEM
THURSDAY WHERE A GALE WARNING MAY BE WARRANTED. WINDS WILL DIMINISH
THURSDAY NIGHT...BUT GUSTS AROUND 20 KNOTS ARE STILL EXPECTED.
HIGH PRESSURE WILL BUILD OVER THE WATERS FOR FRIDAY THROUGH
SATURDAY. THE NEXT DISTURBANCE WILL PASS THROUGH THE WATERS SUNDAY.
&&
.CLIMATE...
VERY COLD WEATHER EXPECTED THIS FRIDAY /16 JAN/ INTO SATURDAY
MORNING /17 JAN/. HOWEVER...SINCE THIS IS NEAR THE CLIMATOLOGICALLY
COLDEST TIME OF YEAR...RECORD LOWS AND/OR RECORD LOW MAXIMUM
TEMPERATURES APPEAR UNLIKELY IN THE IMMEDIATE BALTIMORE/WASHINGTON
METROPOLITAN AREA. STILL...IT DOES LOOK TO BE THE COLDEST AIRMASS
FOR THE AREA IN OVER A DECADE. IT WAS NOTABLY COLDER FOR A FEW DAYS
IN MID JANUARY 1994 AT BWI/DCA/IAD.
BELOW ARE THE FORECAST MAXIMA FOR FRIDAY AND THE FORECAST MINIMA FOR
SATURDAY WITH THE MOST RECENT TIMES TEMPERATURES NEARED THESE
LEVELS...AS WELL AS RECORD LOWEST MAX ON 16 JAN AND RECORD LOW ON 17
JAN.
BWI...FRI FCST HIGH: 18 F /HIGHS OF 5-18 F IN MID JAN 1994 AND 19 F
ON JAN 10 2004 AND FEB 4 1996...RECORD LOW MAXIMUM OF 14 F IN 1893/
DCA...FRI JAN 16 FCST HIGH: 20 F /HIGH OF 17 F ON FEB 4 1996 AND 20
F ON FEB 3 1996 AND 21 F ON JAN 10 2004...RECORD LOW MAXIMUM OF 15 F
IN 1893/
IAD...FRI FCST HIGH: 18 F /HIGH OF 14 F ON FEB 4 1996 AND 19 F ON
JAN 17-18 1997 AND 20 ON FEB 5 2007...RECORD LOW MAXIMUM OF 14 IN
1972 AND 1996/
BWI...SAT FCST LOW: 1 F /LOW OF -1 F ON FEB 5 1996 AND 1 F ON JAN 19
1997...RECORD LOW OF -7 IN 1982/
DCA...SAT FCST LOW: 4 F /LOW OF 5 F ON FEB 5 1996...RECORD LOW OF -5
IN 1982/
IAD...SAT FCST LOW: 1 F /LOW OF -1 F ON FEB 7 1995...RECORD LOW OF
-7 IN 1982/
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...WINTER WEATHER ADVISORY UNTIL 4 AM EST WEDNESDAY FOR MDZ501.
VA...WINTER WEATHER ADVISORY UNTIL 4 AM EST WEDNESDAY FOR VAZ021.
WV...WINTER WEATHER ADVISORY UNTIL 4 AM EST WEDNESDAY FOR WVZ054-
501-503.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST THURSDAY FOR ANZ530>537.
&&
$$
UPDATE...JRK
PREVIOUS DISC...BPP/BJL
000
FXUS61 KRNK 140222
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
922 PM EST TUE JAN 13 2009
.SYNOPSIS...
A COLD FRONT WILL MOVE OFF THE VIRGINIA COAST OVERNIGHT. WEAK
HIGH PRESSURE WILL BUILD IN BRIEFLY WEDNESDAY. AN ARCTIC COLD
FRONT WILL CROSS THE AREA LATE WEDNESDAY NIGHT AND THURSDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
COLD FRONT IS NOW EAST OF ROANOKE...AND WILL CLEAR THE FORECAST
AREA AFTER MIDNIGHT. SNOW SHOWERS IN THE MTNS HAVE TRANSITIONED TO
MAINLY UPSLOPE ON THE WESTERN SLOPES...BUT UPSTREAM RADARS SHOW
NUMEROUS SNOW SHOWERS STILL HEADED THIS WAY...SO I HAVE EXTENDED
THE HIGHER POPS THROUGH 400 AM- ESPECIALLY UPSLOPE AREAS OF SE WV
AS NW TRAJECTORIES CONTINUE THERE THRU MUCH OF THE NIGHT. TEMPS
HAVE DROPPED OFF FAIRLY QUICKLY BEHIND THE COLD FRONT IN THE MTNS.
00Z SOUNDINGS SUPPORT THE 18Z MODEL DATA SHOWING -16C AT 850 MBS
MOVING INTO THE MTNS. I HAVE LOWERED THE OVERNIGHT MINS A FEW
DEGREES FROM THE BLUE RIDGE WEST. MOST MTN LOCATIONS WILL DROP
INTO THE TEENS. STILL DOES NOT LOOK LIKE ENOUGH SNOW FOR AN
ADVISORY- GENERALLY 1 TO 2 INCHES...EXCEPT FOR WESTERN
GREENBRIER...WHICH I HAVE RAISED TO 3-4 INCHES. WILL CONTINUE TO
HANDLE WITH SPS- WITH TEMPS DROPPING SO COLD...UNTREATED ROADS
WILL KEEP SOME SNOW COVER.
THE WINDS BEHIND THE FRONT ARE NEAR THEIR PEAK NOW- GUSTING TO
AROUND 40 MPH IN THE NC MTNS. STILL DO NOT EXPECT ADVISORY LEVEL
WINDS. AS THE HIGH BUILDS INTO THE AREA WED...WINDS WILL BECOME
LIGHT. THERE WILL BE A FEW HOUR PERIOD OF WIND CHILLS AROUND
5 BELOW ZERO OVER THE MTNS OF SE WV AND ELEVATIONS ABOVE 3500 FEET
IN THE NC MTNS TOWARD DAWN. NOT ENOUGH COVERAGE TO WARRANT A WIND
CHILL ADVISORY. HAVE KEPT THE HIGHLIGHT OF THE SNOW AND WIND CHILLS
IN THE HAZARDOUS WEATHER OUTLOOK.
FOR WED...SHOULD SEE PLENTY OF SUN MOST AREAS...WITH FLOW BECOMING
SW AHEAD OF THE ARCTIC BLAST. WENT GENERALLY WITH MAV MOS FOR
HIGHS. WINDS WILL START TO INCREASE OVER THE SW VA/NW NC MTNS
TOWARD THE LATE AFTERNOON AS 40+ KNOT SW 8H JET PUSHES IN AHEAD OF
FRONT. CLOUDS INCREASE LATE IN THE DAY FROM THE NORTHWEST...BUT
ANY PRECIP WILL HOLD OFF UNTIL WED NIGHT.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
ARCTIC FRONT TO CROSS WEDNESDAY NIGHT WITH THE COLDEST AIR THIS
WINTER. AREA OF LOW PRESSURE TAKES A FAVORABLE TRACK FOR AT LEAST
WIND ADVISORY CRITERIA/HIGH WIND WATCH GUSTS AT THE VERY LEAST
ACROSS SW VA AND NW NC. UNIDIRECTIONAL WINDS...AND THE JET
DIRECTORY OVERHEAD OF ASHE/WATAUGA/GRAYSON...ALONG WITH AN
IMPRESSIVE ISENT OMEGA RISE/FALL COUPLET MAY PRODUCE WIND GUSTS
STRONGER THAN EVEN BUFKIT IS FORECASTING RIGHT NOW. WOULD LIKE TO
SEE MORE DOWNGLIDE FROM AN ISENTROPIC PERSPECTIVE THOUGH. AN EVENT
SIMILAR TO THIS WAS UNDER FORECASTED BY THE MODELS A FEW WEAKS AGO.
AFTER COORD WITH GSP...DECIDED NOT TO HOIST A HIGH WIND WATCH BUT
THIS NEEDS TO BE CONSIDERED LATER FOR WED NIGHT THROUGH THUR
AFTERNOON...BUT MOST LIKELY WHEN THE ARCTIC CROSSES NEAR DAWN
THURSDAY. MIDLEVEL LAPSE RATES AND STRENGTH OF FRONT INDICATE SOME
SNOW SQUALLS POSSIBLY ALONG THE FRONT ACROSS SE WEST VA LATER
WEDNESDAY NIGHT...WITH A QUICK INCH OR TWO ALONG THE FAVORED
SPOTS. ANOTHER INCH OR TWO COULD FALL THURSDAY. ALTHOUGH
FAVORABLE UPSLOPE CONDITIONS WANE THURSDAY...A SHRTWV DROPPING
INTO THE CWA MAY PROVIDE ANOTHER SHOT OF SNOW INTO THE BLUE RIDGE
ON THURSDAY AFTERNOON. SEEMS AS THE 12Z MEX IS FINALLY REALIZING
THE STRENGTH OF THIS AIRMASS...SO GENERALLY FOLLOWED IT ON DAY
4...WHILE UNDERCUTTING MOS LEADING UP TO THAT POINT WITH THE
SHALLOW ARCTIC AIR. A WIND CHIL ADVISORY WILL ALSO BE NEEDED
PERHAPS AS EARLY AS WEDNESDAY NIGHT. IF NO HIGH CLOUDS ARRIVE
FRIDAY NIGHT...AND MOST SPOTS ARE ABLE TO DECOUPLE...AOB 0F IS
POSSIBLE ALONG THE BLUE RIDGE AND INTO SE WEST VA WITH STRONG HIGH
OVERHEAD.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ARCTIC DOME OF HIGH PRESSURE WILL BE LOCATED ACROSS OUR REGION
SATURDAY MORNING WITH VERY COLD READINGS IN THE SINGLE DIGITS TO
LOWER TEENS. AREAS WITH ANY SNOW COVER COULD SEE SUBZERO SINGLE
DIGIT LOWS...EVERYONE ELSE SHOULD STAY ON THE PLUS SIDE OF ZERO.
HIGH PRESSURE WILL SLIDE EAST ON SATURDAY. TEMPERATURES SHOULD
GRADUALLY MODERATE SATURDAY AFTERNOON INTO SUNDAY AHEAD OF ANOTHER
CONTINENTAL FRONT THAT WILL CROSS THE FORECAST AREA. CONTINUED THE
CHANCE OF SNOW WITH ITS PASSAGE SATURDAY NIGHT INTO SUNDAY. KEPT
LIGHT CHC POPS IN THE WESTERN MOUNTAINS SUNDAY NIGHT INTO MONDAY.
NEXT FRONT ARRIVES ON TUESDAY WITH CHANCE FOR RAIN AND SNOW. LEANED
EARLY NEXT WEEK TOWARDS THE ECMWF WITH ADDITIONAL CLOUDS AND
POPS...WHICH DIVES SYSTEM FURTHER SOUTH WITH COASTAL LOW DEVELOPMENT
COMPARED TO GFS. PLAYED TEMPERATURES CLOSE TO HPCGUIDE.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
A COLD FRONT WILL TRAVEL EAST ACROSS THE REGION TONIGHT. THE COLD
FRONT HAS REACH THE WESTERN MOUNTAINS AND SHOULD CLEAR DAN BY
04Z. MVFR/IFR CIGS IN SNOW SHOWERS ARE POSSIBLE. ELSEWHERE...VFR
CONDITIONS ARE EXPECTED. WINDS MAY GUST UP TO 25-30 KNOTS THIS
EVENING FOR A 6 HOUR OR LESS PERIOD...MAINLY LEE OF THE HIGHLANDS
AND ALONG/JUST EAST OF THE BLUE RIDGE.
CIGS WILL REMAIN MVFR AT BLF/LWB THROUGH DAYBREAK B4 DRIER AIR
SCATTERS OUT THE LOW LVLS. ELSEWHERE...LOOK FOR VFR CIGS OVERNIGHT
THEN CLEARING.
A STRONGER ARCTIC COLD FRONT WILL CROSS THE AREA WEDNESDAY NIGHT
ENHANCING THE THREAT FOR WESTERN MVFR CIGS/VSBYS IN MOUNTAIN SNOW
SHOWERS AND STRONG WINDS AT HIGHER ELEVATIONS THROUGH THURSDAY.
ANOTHER STORM ARRIVES SATURDAY NIGHT INTO SUNDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS/WP
NEAR TERM...JJ/WP
SHORT TERM...KM
LONG TERM...KK
AVIATION...AMS/KK/WP
000
FXUS61 KAKQ 140058
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
758 PM EST TUE JAN 13 2009
.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA TONIGHT...AS AN AREA OF LOW
PRESSURE MOVES FURTHER OFF THE MID ATLANTIC COAST. HIGH PRESSURE
BRIEFLY BUILDS IN FROM THE SOUTHWEST ON WEDNESDAY...WITH A STRONG
COLD FRONT CROSSING THE REGION ON THURSDAY. ARCTIC HIGH PRESSURE
WILL USHER IN A COLD AIRMASS FRIDAY INTO SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
CDFRNT APPRCHG WRN CNTYS IS HELPING TO KICK COASTAL LOW FRTHR OUT
TO SEA ERLY THIS EVE. LTST RADAR TRENDS HAS PCPN BASICALLY CONFINED
TO SERN CSTL AND ERN SHORE AREAS WITH LTST RUC INDCTG ANTHR 1-3 HRS
OF PCPN XPCTD B4 IT ALL MOVES OFFSHORE. MEANWHILE...SAT LOOP CONTS
TO SHOW LOW LVL CLDS QUICKLY GETTING SCOURED OUT TO A BKN MID AND
HIGH LVL DECK ACROSS WRN HALF OF FA. THUS DID A ERLY EVE UPDATE TO
ACCOUNT FOR THESE LTST TRENDS.
NXT CONCERN WILL BE THE PTNTL FOR BLACK ICE LATER TONIGHT (IN AREAS
THAT RCVD MEASURABLE RAIN PAST SVRL HRS) AS SKIES CLR AND TMPS DROP
TO ARND 30 ACROSS SERN CNTYS...BTWN 25-30 ERN SHORE AREAS. PLAN IS
TO ISSUE AN SPS BY LATE EVE MAINLY FOR WED MORN COMMUTE.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY NIGHT/...
DRY CONDS START OUT THE DAY ON WEDNESDAY AS THE FRONT CONTINUES TO
PUSH OFFSHORE AND WEAK HIGH PRESSURE BUILDS IN. EVEN WITH CLEAR
SKIES TO START OUT THE DAY...CAA AND INCREASING CLOUDS WILL KEEP MAX
TEMPS DOWN IN THE MID 30S (WEST AND NORTH WHERE THEY`LL SEE CLOUDS
SOONER IN THE DAY) TO AROUND 40 DEGREES IN THE SOUTH/SOUTHEAST
AREAS. ANOTHER FAST MVG SYSTEM MVS TOWARDS THE AREA IN THE AFTN/EVNG
HRS BUT HIGH TO OUR SE WILL KEEP THE LOW TO OUR NORTH. HAVE
CONTINUED ONLY SILENT POPS WITH THIS SYSTEM DUE TO LACK OF MOISTURE
AND THE FACT TAHT MOST OF THE ENERGY REMAINS TO OUR NORTH. SHOULD
STILL SEE PLENTY OF CLOUDS WED NIGHT INTO THURS WITH THIS FEATURE
HOWEVER.
TROUGH MVS OVER THE EAST COAST THURS NIGHT/FRI MORNING...SO A BIG
CHANGE EXPECTED GOING INTO FRIDAY MORNING. CLEARING SKIES THURS
NIGHT ALONG WITH LIGHT WINDS AND STRONG CAA WILL ALLOW TEMPS TO DROP
INTO THE TEENS MOST LOCATIONS. GUIDANCE HAS BEEN TRENDING COLDER AND
THEREFORE HAVE DROPPED MINS A FEW DEGREES FROM PREVIOUS FCST. STRONG
HIGH BUILDS INTO THE OH VALLEY ON FRIDAY...KEEPING MAX TEMPS DOWN
BLO FREEZING AND MOCLEAR SKIES OVER THE AREA.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
HIGH PRES BUILDS IN FROM THE W FRI NIGHT THRU SAT NIGHT. FRIGID LOW
TEMPS WILL CONT FRI NIGHT...ONLY NEAR 10 NW/N TO NEAR 20 SE. TEMPS
START TO MODERATE ON SAT AS THE FLOW BECOMES SW WITH THE HIGH
SLIDING OFFSHORE. HIGHS `WARM` SAT INTO THE LWR TO MID 30S. LOWS
ALSO MILDER SAT NIGHT...NEAR 20 NW TO NEAR 30 SE.
SEVERAL TROFS/AREAS OF LOW PRES WILL THEN ROTATE THRU THE MID-
ATLANTIC FROM SUN THRU EARLY NEXT WEEK. FCST MODEL SOUNDINGS SHOW
PLENTY OF DRY AIR IN PLACE AS EACH TROF MOVES THRU...AND GIVEN THE
TRAJECTORY OF EACH WAVE EXPECT THAT IT WILL BE DIFFICULT TO GET MUCH
IF ANY MEASURABLE PRECIP OUT OF THESE FEATURES. IF MODELS START TO
TREND WITH A TRACK FARTHER TO THE S THEN WILL NEED TO INCREASE THE
CHANCE OF PRECIP. WILL KEEP POPS CAPPED BETWEEN 20-30% AT THIS TIME.
AT ANY RATE...COLD AIR WILL REMAIN IN PLACE THRU AT LEAST EARLY NEXT
WEEK (ALTHO NOT AS COLD AS FRI-SAT). HIGHS WILL BE IN THE UPR 30S
NW/N TO MID 40S SE...LOWS IN THE LWR 20S NW/N TO NEAR 30 SE.
&&
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
LOW PRESSURE OFF THE SE VA/NE NC CST...WILL LIFT QUICKLY NE AWAY
FM THE AREA TNGT. LGT RAIN WAS STILL RIGHT ALNG THE CST ARND 745
PM BUT WILL BE MOVNG OUT TO SEA IN THE NEXT COUPLE OF HRS. CIGS
AND VSBYS WILL IMPROVE QUICKLY TO MAINLY VFR CONDS...AND NW WNDS
WILL INCRS OVRNGT...AS HI PRES STARTS TO BLD IN FM THE W.
VFR CONDITIONS WILL PREVAIL DURING THE NEXT SEVERAL DAYS. WINDS
WILL BE GUSTY AT TIMES THU AS AN ARCTIC COLD FRONT CROSSES THE
AREA. A LOW PRESSURE SYSTEM MAY IMPACT THE AREA SUN WITH A CHANCE
OF PRECIPITATION AND POSSIBLY LOWERING AVIATION CONDITIONS.
&&
.MARINE...
AN AREA OF LOW PRES WILL CONTINUE TO DEVELOP/DEEPEN OFF THE NC OBX.
THE LOW WILL MOVE TO THE NE AND AWAY FROM THE COAST TONIGHT...AS A
COLD FRONT SWEEPS IN FROM THE W. WINDS/SEAS WILL INCREASE/BUILD
LATER THIS EVENING...AND SCA FLAGS REMAIN IN EFFECT...BEGINNING AT
03Z TONIGHT. WINDS WILL BE THE STRONGEST OVER THE NRN WATERS COASTAL
WATERS FROM CAPE CHARLES LIGHT VA NORTHWARD...AND HAVE GALE WARNINGS
IN EFFECT FOR THOSE ZONES. ONLY EXPECT ABOUT A 6 HR WINDOW FOR GALE
FORCE WINDS TO OCCUR...FROM MIDNIGHT THRU SUNRISE. AFTERWARD WINDS
WILL START TO DIMINISH AND SEAS WILL SLOWLY SUBSIDE AS HIGH PRES
BRIEFLY BUILDS IN FROM THE W ON WED.
ANOTHER AREA OF LOW PRES WILL MOVE ACROSS THE MID-ATLANTIC FROM THE
W WED NIGHT THRU THU...AND HIGH END SCA TO LOW END GALE CONDITIONS
ARE EXPECTED YET AGAIN. HIGH PRES RETURNS LATE FRI THRU SAT
NIGHT...WITH ANOTHER LOW PRES SYSTEM AFFECTING THE REGION BY THE END
OF THE WEEKEND INTO EARLY NEXT WEEK.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST WEDNESDAY FOR ANZ630>633-
656-658.
GALE WARNING FROM 1 AM TO 7 AM EST WEDNESDAY FOR ANZ650-652-
654.
&&
$$
SYNOPSIS...JYM
NEAR TERM...JYM/MPR
SHORT TERM...JYM
LONG TERM...JRL
AVIATION...TMG
MARINE...JRL
000
FXUS61 KAKQ 132358
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
658 PM EST TUE JAN 13 2009
.SYNOPSIS...
A COLD FRONT WILL CROSS THE AREA TONIGHT...AS AN AREA OF LOW
PRESSURE MOVES FURTHER OFF THE MID ATLANTIC COAST. HIGH PRESSURE
BRIEFLY BUILDS IN FROM THE SOUTHWEST ON WEDNESDAY...WITH A STRONG
COLD FRONT CROSSING THE REGION ON THURSDAY. ARCTIC HIGH PRESSURE
WILL USHER IN A COLD AIRMASS FRIDAY INTO SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
CDFRNT APPRCHG WRN CNTYS IS HELPING TO KICK COASTAL LOW FRTHR OUT
TO SEA ERLY THIS EVE. LTST RADAR TRENDS HAS PCPN BASICALLY CONFINED
TO SERN CSTL AND ERN SHORE AREAS WITH LTST RUC INDCTG ANTHR 1-3 HRS
OF PCPN XPCTD B4 IT ALL MOVES OFFSHORE. MEANWHILE...SAT LOOP CONTS
TO SHOW LOW LVL CLDS QUICKLY GETTING SCOURED OUT TO A BKN MID AND
HIGH LVL DECK ACROSS WRN HALF OF FA. THUS DID A ERLY EVE UPDATE TO
ACCOUNT FOR THESE LTST TRENDS.
NXT CONCERN WILL BE THE PTNTL FOR BLACK ICE LATER TONIGHT (IN AREAS
THAT RCVD MEASURABLE RAIN PAST SVRL HRS) AS SKIES CLR AND TMPS DROP
TO ARND 30 ACROSS SERN CNTYS...BTWN 25-30 ERN SHORE AREAS. PLAN IS
TO ISSUE AN SPS BY LATE EVE MAINLY FOR WED MORN COMMUTE.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY NIGHT/...
DRY CONDS START OUT THE DAY ON WEDNESDAY AS THE FRONT CONTINUES TO
PUSH OFFSHORE AND WEAK HIGH PRESSURE BUILDS IN. EVEN WITH CLEAR
SKIES TO START OUT THE DAY...CAA AND INCREASING CLOUDS WILL KEEP MAX
TEMPS DOWN IN THE MID 30S (WEST AND NORTH WHERE THEY`LL SEE CLOUDS
SOONER IN THE DAY) TO AROUND 40 DEGREES IN THE SOUTH/SOUTHEAST
AREAS. ANOTHER FAST MVG SYSTEM MVS TOWARDS THE AREA IN THE AFTN/EVNG
HRS BUT HIGH TO OUR SE WILL KEEP THE LOW TO OUR NORTH. HAVE
CONTINUED ONLY SILENT POPS WITH THIS SYSTEM DUE TO LACK OF MOISTURE
AND THE FACT TAHT MOST OF THE ENERGY REMAINS TO OUR NORTH. SHOULD
STILL SEE PLENTY OF CLOUDS WED NIGHT INTO THURS WITH THIS FEATURE
HOWEVER.
TROUGH MVS OVER THE EAST COAST THURS NIGHT/FRI MORNING...SO A BIG
CHANGE EXPECTED GOING INTO FRIDAY MORNING. CLEARING SKIES THURS
NIGHT ALONG WITH LIGHT WINDS AND STRONG CAA WILL ALLOW TEMPS TO DROP
INTO THE TEENS MOST LOCATIONS. GUIDANCE HAS BEEN TRENDING COLDER AND
THEREFORE HAVE DROPPED MINS A FEW DEGREES FROM PREVIOUS FCST. STRONG
HIGH BUILDS INTO THE OH VALLEY ON FRIDAY...KEEPING MAX TEMPS DOWN
BLO FREEZING AND MOCLEAR SKIES OVER THE AREA.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
HIGH PRES BUILDS IN FROM THE W FRI NIGHT THRU SAT NIGHT. FRIGID LOW
TEMPS WILL CONT FRI NIGHT...ONLY NEAR 10 NW/N TO NEAR 20 SE. TEMPS
START TO MODERATE ON SAT AS THE FLOW BECOMES SW WITH THE HIGH
SLIDING OFFSHORE. HIGHS `WARM` SAT INTO THE LWR TO MID 30S. LOWS
ALSO MILDER SAT NIGHT...NEAR 20 NW TO NEAR 30 SE.
SEVERAL TROFS/AREAS OF LOW PRES WILL THEN ROTATE THRU THE MID-
ATLANTIC FROM SUN THRU EARLY NEXT WEEK. FCST MODEL SOUNDINGS SHOW
PLENTY OF DRY AIR IN PLACE AS EACH TROF MOVES THRU...AND GIVEN THE
TRAJECTORY OF EACH WAVE EXPECT THAT IT WILL BE DIFFICULT TO GET MUCH
IF ANY MEASURABLE PRECIP OUT OF THESE FEATURES. IF MODELS START TO
TREND WITH A TRACK FARTHER TO THE S THEN WILL NEED TO INCREASE THE
CHANCE OF PRECIP. WILL KEEP POPS CAPPED BETWEEN 20-30% AT THIS TIME.
AT ANY RATE...COLD AIR WILL REMAIN IN PLACE THRU AT LEAST EARLY NEXT
WEEK (ALTHO NOT AS COLD AS FRI-SAT). HIGHS WILL BE IN THE UPR 30S
NW/N TO MID 40S SE...LOWS IN THE LWR 20S NW/N TO NEAR 30 SE.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
A LOW PRESSURE SYSTEM WAS CENTERED ABOUT 40 MILES S OF CAPE
LOOKOUT NC AT 17Z. LIGHT RAIN HAS BROKEN OUT ACROSS ERN NC AND FAR
SE VA. CEILINGS HAVE LOWERED AT THE TAF SITES WITH IFR AT ECG AND MVFR
PRESENT OR SOON TO DEVELOP AT THE OTHER TAF SITES. AS THE LOW
MOVES OFF TO THE NE...RAIN WILL END AROUND 00Z. VFR CONDITIONS
WILL DEVELOP TONIGHT AND CONTINUE WED AS HIGH PRESSURE BUILDS
INTO THE AREA.
VFR CONDITIONS WILL PREVAIL DURING THE NEXT SEVERAL DAYS. WINDS
WILL BE GUSTY AT TIMES THU AS AN ARCTIC COLD FRONT CROSSES THE
AREA. A LOW PRESSURE SYSTEM MAY IMPACT THE AREA SUN WITH A CHANCE
OF PRECIPITATION AND POSSIBLY LOWERING AVIATION CONDITIONS.
&&
.MARINE...
AN AREA OF LOW PRES WILL CONTINUE TO DEVELOP/DEEPEN OFF THE NC OBX.
THE LOW WILL MOVE TO THE NE AND AWAY FROM THE COAST TONIGHT...AS A
COLD FRONT SWEEPS IN FROM THE W. WINDS/SEAS WILL INCREASE/BUILD
LATER THIS EVENING...AND SCA FLAGS REMAIN IN EFFECT...BEGINNING AT
03Z TONIGHT. WINDS WILL BE THE STRONGEST OVER THE NRN WATERS COASTAL
WATERS FROM CAPE CHARLES LIGHT VA NORTHWARD...AND HAVE GALE WARNINGS
IN EFFECT FOR THOSE ZONES. ONLY EXPECT ABOUT A 6 HR WINDOW FOR GALE
FORCE WINDS TO OCCUR...FROM MIDNIGHT THRU SUNRISE. AFTERWARD WINDS
WILL START TO DIMINISH AND SEAS WILL SLOWLY SUBSIDE AS HIGH PRES
BRIEFLY BUILDS IN FROM THE W ON WED.
ANOTHER AREA OF LOW PRES WILL MOVE ACROSS THE MID-ATLANTIC FROM THE
W WED NIGHT THRU THU...AND HIGH END SCA TO LOW END GALE CONDITIONS
ARE EXPECTED YET AGAIN. HIGH PRES RETURNS LATE FRI THRU SAT
NIGHT...WITH ANOTHER LOW PRES SYSTEM AFFECTING THE REGION BY THE END
OF THE WEEKEND INTO EARLY NEXT WEEK.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 1 PM EST
WEDNESDAY FOR ANZ630>633-656-658.
GALE WARNING FROM 1 AM TO 7 AM EST WEDNESDAY FOR ANZ650-652-
654.
&&
$$
SYNOPSIS...JYM/MPR
NEAR TERM...JYM/MPR
SHORT TERM...JYM
LONG TERM...JRL
AVIATION...LSA
MARINE...JRL
000
FXUS61 KRNK 132357
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
657 PM EST TUE JAN 13 2009
.SYNOPSIS...
A COLD FRONT IS GOING TO MOVE TO THE VIRGINIA COAST TONIGHT WITH A
WEAK HIGH PRESSURE BUILDING IN BRIEFLY WEDNESDAY. AN ARCTIC COLD
FRONT WILL CROSS THE AREA LATE WEDNESDAY NIGHT AND THURSDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
HAVE ISSUED A QUICK UPDATE TO RAISE POPS IN THE MTNS. INITIAL BAND
OF SNOW SHOWERS MOVING THROUGH MAY MAKE IT TO THE BLUE RIDGE
BEFORE WE TRANSITION TO MAINLY UPSLOPE SNOW SHOWERS BY 03Z.
PREVIOUS DISCUSSION...
COLD FRONT OVER THE CENTRAL APPS WILL SHIFT EAST THROUGH THE AREA
THIS EVENING. SHORTWAVE OVER THE GULF COAST STATES WILL SHIFT
NORTHEAST INTO THE CAROLINAS THIS EVENING AND INTO CENTRAL VA
OVERNIGHT BEFORE SHEARING INTO THE MID ATLANTIC 12Z WED.
MOISTURE WITH THE FRONT IS NARROW...BUT DEEP ENOUGH THAT ONCE IT
GETS INTO SE WV WILL BRING LIKELY TO CAT SNOW SHOWERS THIS
EVENING. ONCE THE FRONT AND SHORTWAVE MOVE EAST...NW FLOW WILL
CONTINUE BUT MOISTURE BECOMES SHALLOW RATHER FAST. WESTERLY FLOW
WITH PRE-FRONT TROUGH WILL INHIBIT PRECIP FROM MAKING IT EAST OF
THE BLUE RIDGE...EXCEPT A FEW FLURRIES. TRAJECTORIES OVERALL STILL
APPEAR TO LACK A LAKE CONNECTION...EXCEPT FOR A BRIEF PERIOD THIS
EVENING OVER SE WV. LIQUID TO SNOW RATIOS WILL INCREASE TO 20 OR
25 TO 1 BY MIDNIGHT. ATTM...LOOKS LIKE A DUSTING TO ONE INCH
EXPECTED FROM THE WRN SLOPES OF THE NC MTNS THROUGH FAR SW VA INTO
SE WV THRU 12Z WED...WITH 1-3 INCHES EXPECTED OVER THE WRN SLOPES
OF GREENBRIER SOUTH INTO NRN SUMMERS.
TEMPS STARTING OFF CHILL TODAY OUT EAST...ALTHOUGH VSBL SAT
INDICATES THE EWD MOVEMENT TO THE CIRRUS SHIELD SO SOME WARMING
MAY TAKE PLACE FOR 1-2 HOURS. THE MAV MOS LOWS TONIGHT LOOK
REASONABLE...LOOKING AT TEENS IN THE WEST...20S EAST. THE WINDS
BEHIND THE FRONT WILL GUST FOR ABOUT 4-6 HOURS. NOT LOOKING AT
ADVISORY WINDS. AS THE HIGH BUILDS INTO THE AREA WED...WINDS WILL
BECOME LIGHT. THERE WILL BE A SMALL WINDOW OF WIND CHILLS
APPROACHING ZERO TO -5 OVER THE MTNS OF SE WV TOWARD DAWN...AND
MAINLY IN GREENBRIER COUNTY. HAVE HIGHLIGHTED THE SNOW AND WIND
CHILLS IN THE HAZARDOUS WEATHER OUTLOOK.
FOR WED...SHOULD SEE PLENTY OF SUN MOST AREAS...WITH FLOW BECOMING
SW AHEAD OF THE ARCTIC BLAST. WENT GENERALLY WITH MAV MOS FOR
HIGHS. WINDS WILL START TO INCREASE OVER THE SW VA/NW NC MTNS
TOWARD THE LATE AFTERNOON AS 40+ KNOT SW 8H JET PUSHES IN AHEAD OF
FRONT. CLOUDS INCREASE LATE IN THE DAY FROM THE NORTHWEST...BUT
ANY PRECIP WILL HOLD OFF UNTIL WED NIGHT.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
ARCTIC FRONT TO CROSS WEDNESDAY NIGHT WITH THE COLDEST AIR THIS
WINTER. AREA OF LOW PRESSURE TAKES A FAVORABLE TRACK FOR AT LEAST
WIND ADVISORY CRITERIA/HIGH WIND WATCH GUSTS AT THE VERY LEAST
ACROSS SW VA AND NW NC. UNIDIRECTIONAL WINDS...AND THE JET
DIRECTORY OVERHEAD OF ASHE/WATAUGA/GRAYSON...ALONG WITH AN
IMPRESSIVE ISENT OMEGA RISE/FALL COUPLET MAY PRODUCE WIND GUSTS
STRONGER THAN EVEN BUFKIT IS FORECASTING RIGHT NOW. WOULD LIKE TO
SEE MORE DOWNGLIDE FROM AN ISENTROPIC PERSPECTIVE THOUGH. AN EVENT
SIMILAR TO THIS WAS UNDER FORECASTED BY THE MODELS A FEW WEAKS AGO.
AFTER COORD WITH GSP...DECIDED NOT TO HOIST A HIGH WIND WATCH BUT
THIS NEEDS TO BE CONSIDERED LATER FOR WED NIGHT THROUGH THUR
AFTERNOON...BUT MOST LIKELY WHEN THE ARCTIC CROSSES NEAR DAWN
THURSDAY. MIDLEVEL LAPSE RATES AND STRENGTH OF FRONT INDICATE SOME
SNOW SQUALLS POSSIBLY ALONG THE FRONT ACROSS SE WEST VA LATER
WEDNESDAY NIGHT...WITH A QUICK INCH OR TWO ALONG THE FAVORED
SPOTS. ANOTHER INCH OR TWO COULD FALL THURSDAY. ALTHOUGH
FAVORABLE UPSLOPE CONDITIONS WANE THURSDAY...A SHRTWV DROPPING
INTO THE CWA MAY PROVIDE ANOTHER SHOT OF SNOW INTO THE BLUE RIDGE
ON THURSDAY AFTERNOON. SEEMS AS THE 12Z MEX IS FINALLY REALIZING
THE STRENGTH OF THIS AIRMASS...SO GENERALLY FOLLOWED IT ON DAY
4...WHILE UNDERCUTTING MOS LEADING UP TO THAT POINT WITH THE
SHALLOW ARCTIC AIR. A WIND CHIL ADVISORY WILL ALSO BE NEEDED
PERHAPS AS EARLY AS WEDNESDAY NIGHT. IF NO HIGH CLOUDS ARRIVE
FRIDAY NIGHT...AND MOST SPOTS ARE ABLE TO DECOUPLE...AOB 0F IS
POSSIBLE ALONG THE BLUE RIDGE AND INTO SE WEST VA WITH STRONG HIGH
OVERHEAD.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ARCTIC DOME OF HIGH PRESSURE WILL BE LOCATED ACROSS OUR REGION
SATURDAY MORNING WITH VERY COLD READINGS IN THE SINGLE DIGITS TO
LOWER TEENS. AREAS WITH ANY SNOW COVER COULD SEE SUBZERO SINGLE
DIGIT LOWS...EVERYONE ELSE SHOULD STAY ON THE PLUS SIDE OF ZERO.
HIGH PRESSURE WILL SLIDE EAST ON SATURDAY. TEMPERATURES SHOULD
GRADUALLY MODERATE SATURDAY AFTERNOON INTO SUNDAY AHEAD OF ANOTHER
CONTINENTAL FRONT THAT WILL CROSS THE FORECAST AREA. CONTINUED THE
CHANCE OF SNOW WITH ITS PASSAGE SATURDAY NIGHT INTO SUNDAY. KEPT
LIGHT CHC POPS IN THE WESTERN MOUNTAINS SUNDAY NIGHT INTO MONDAY.
NEXT FRONT ARRIVES ON TUESDAY WITH CHANCE FOR RAIN AND SNOW. LEANED
EARLY NEXT WEEK TOWARDS THE ECMWF WITH ADDITIONAL CLOUDS AND
POPS...WHICH DIVES SYSTEM FURTHER SOUTH WITH COASTAL LOW DEVELOPMENT
COMPARED TO GFS. PLAYED TEMPERATURES CLOSE TO HPCGUIDE.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
A COLD FRONT WILL TRAVEL EAST ACROSS THE REGION TONIGHT. THE COLD
FRONT HAS REACH THE WESTERN MOUNTAINS AND SHOULD CLEAR DAN BY
04Z. MVFR/IFR CIGS IN SNOW SHOWERS ARE POSSIBLE. ELSEWHERE...VFR
CONDITIONS ARE EXPECTED. WINDS MAY GUST UP TO 25-30 KNOTS THIS
EVENING FOR A 6 HOUR OR LESS PERIOD...MAINLY LEE OF THE HIGHLANDS
AND ALONG/JUST EAST OF THE BLUE RIDGE.
CIGS WILL REMAIN MVFR AT BLF/LWB THROUGH DAYBREAK B4 DRIER AIR
SCATTERS OUT THE LOW LVLS. ELSEWHERE...LOOK FOR VFR CIGS OVERNIGHT
THEN CLEARING.
A STRONGER ARCTIC COLD FRONT WILL CROSS THE AREA WEDNESDAY NIGHT
ENHANCING THE THREAT FOR WESTERN MVFR CIGS/VSBYS IN MOUNTAIN SNOW
SHOWERS AND STRONG WINDS AT HIGHER ELEVATIONS THROUGH THURSDAY.
ANOTHER STORM ARRIVES SATURDAY NIGHT INTO SUNDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS/WP
NEAR TERM...JJ/WP
SHORT TERM...KM
LONG TERM...KK
AVIATION...AMS/KK/WP
000
FXUS61 KRNK 132315
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
615 PM EST TUE JAN 13 2009
.SYNOPSIS...
A COLD FRONT IS GOING TO MOVE TO THE VIRGINIA COAST TONIGHT WITH A
WEAK HIGH PRESSURE BUILDING IN BRIEFLY WEDNESDAY. AN ARCTIC COLD
FRONT WILL CROSS THE AREA LATE WEDNESDAY NIGHT AND THURSDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
HAVE ISSUED A QUICK UPDATE TO RAISE POPS IN THE MTNS. INITIAL BAND
OF SNOW SHOWERS MOVING THROUGH MAY MAKE IT TO THE BLUE RIDGE
BEFORE WE TRANSITION TO MAINLY UPSLOPE SNOW SHOWERS BY 03Z.
PREVIOUS DISCUSSION...
COLD FRONT OVER THE CENTRAL APPS WILL SHIFT EAST THROUGH THE AREA
THIS EVENING. SHORTWAVE OVER THE GULF COAST STATES WILL SHIFT
NORTHEAST INTO THE CAROLINAS THIS EVENING AND INTO CENTRAL VA
OVERNIGHT BEFORE SHEARING INTO THE MID ATLANTIC 12Z WED.
MOISTURE WITH THE FRONT IS NARROW...BUT DEEP ENOUGH THAT ONCE IT
GETS INTO SE WV WILL BRING LIKELY TO CAT SNOW SHOWERS THIS
EVENING. ONCE THE FRONT AND SHORTWAVE MOVE EAST...NW FLOW WILL
CONTINUE BUT MOISTURE BECOMES SHALLOW RATHER FAST. WESTERLY FLOW
WITH PRE-FRONT TROUGH WILL INHIBIT PRECIP FROM MAKING IT EAST OF
THE BLUE RIDGE...EXCEPT A FEW FLURRIES. TRAJECTORIES OVERALL STILL
APPEAR TO LACK A LAKE CONNECTION...EXCEPT FOR A BRIEF PERIOD THIS
EVENING OVER SE WV. LIQUID TO SNOW RATIOS WILL INCREASE TO 20 OR
25 TO 1 BY MIDNIGHT. ATTM...LOOKS LIKE A DUSTING TO ONE INCH
EXPECTED FROM THE WRN SLOPES OF THE NC MTNS THROUGH FAR SW VA INTO
SE WV THRU 12Z WED...WITH 1-3 INCHES EXPECTED OVER THE WRN SLOPES
OF GREENBRIER SOUTH INTO NRN SUMMERS.
TEMPS STARTING OFF CHILL TODAY OUT EAST...ALTHOUGH VSBL SAT
INDICATES THE EWD MOVEMENT TO THE CIRRUS SHIELD SO SOME WARMING
MAY TAKE PLACE FOR 1-2 HOURS. THE MAV MOS LOWS TONIGHT LOOK
REASONABLE...LOOKING AT TEENS IN THE WEST...20S EAST. THE WINDS
BEHIND THE FRONT WILL GUST FOR ABOUT 4-6 HOURS. NOT LOOKING AT
ADVISORY WINDS. AS THE HIGH BUILDS INTO THE AREA WED...WINDS WILL
BECOME LIGHT. THERE WILL BE A SMALL WINDOW OF WIND CHILLS
APPROACHING ZERO TO -5 OVER THE MTNS OF SE WV TOWARD DAWN...AND
MAINLY IN GREENBRIER COUNTY. HAVE HIGHLIGHTED THE SNOW AND WIND
CHILLS IN THE HAZARDOUS WEATHER OUTLOOK.
FOR WED...SHOULD SEE PLENTY OF SUN MOST AREAS...WITH FLOW BECOMING
SW AHEAD OF THE ARCTIC BLAST. WENT GENERALLY WITH MAV MOS FOR
HIGHS. WINDS WILL START TO INCREASE OVER THE SW VA/NW NC MTNS
TOWARD THE LATE AFTERNOON AS 40+ KNOT SW 8H JET PUSHES IN AHEAD OF
FRONT. CLOUDS INCREASE LATE IN THE DAY FROM THE NORTHWEST...BUT
ANY PRECIP WILL HOLD OFF UNTIL WED NIGHT.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
ARCTIC FRONT TO CROSS WEDNESDAY NIGHT WITH THE COLDEST AIR THIS
WINTER. AREA OF LOW PRESSURE TAKES A FAVORABLE TRACK FOR AT LEAST
WIND ADVISORY CRITERIA/HIGH WIND WATCH GUSTS AT THE VERY LEAST
ACROSS SW VA AND NW NC. UNIDIRECTIONAL WINDS...AND THE JET
DIRECTORY OVERHEAD OF ASHE/WATAUGA/GRAYSON...ALONG WITH AN
IMPRESSIVE ISENT OMEGA RISE/FALL COUPLET MAY PRODUCE WIND GUSTS
STRONGER THAN EVEN BUFKIT IS FORECASTING RIGHT NOW. WOULD LIKE TO
SEE MORE DOWNGLIDE FROM AN ISENTROPIC PERSPECTIVE THOUGH. AN EVENT
SIMILAR TO THIS WAS UNDER FORECASTED BY THE MODELS A FEW WEAKS AGO.
AFTER COORD WITH GSP...DECIDED NOT TO HOIST A HIGH WIND WATCH BUT
THIS NEEDS TO BE CONSIDERED LATER FOR WED NIGHT THROUGH THUR
AFTERNOON...BUT MOST LIKELY WHEN THE ARCTIC CROSSES NEAR DAWN
THURSDAY. MIDLEVEL LAPSE RATES AND STRENGTH OF FRONT INDICATE SOME
SNOW SQUALLS POSSIBLY ALONG THE FRONT ACROSS SE WEST VA LATER
WEDNESDAY NIGHT...WITH A QUICK INCH OR TWO ALONG THE FAVORED
SPOTS. ANOTHER INCH OR TWO COULD FALL THURSDAY. ALTHOUGH
FAVORABLE UPSLOPE CONDITIONS WANE THURSDAY...A SHRTWV DROPPING
INTO THE CWA MAY PROVIDE ANOTHER SHOT OF SNOW INTO THE BLUE RIDGE
ON THURSDAY AFTERNOON. SEEMS AS THE 12Z MEX IS FINALLY REALIZING
THE STRENGTH OF THIS AIRMASS...SO GENERALLY FOLLOWED IT ON DAY
4...WHILE UNDERCUTTING MOS LEADING UP TO THAT POINT WITH THE
SHALLOW ARCTIC AIR. A WIND CHIL ADVISORY WILL ALSO BE NEEDED
PERHAPS AS EARLY AS WEDNESDAY NIGHT. IF NO HIGH CLOUDS ARRIVE
FRIDAY NIGHT...AND MOST SPOTS ARE ABLE TO DECOUPLE...AOB 0F IS
POSSIBLE ALONG THE BLUE RIDGE AND INTO SE WEST VA WITH STRONG HIGH
OVERHEAD.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ARCTIC DOME OF HIGH PRESSURE WILL BE LOCATED ACROSS OUR REGION
SATURDAY MORNING WITH VERY COLD READINGS IN THE SINGLE DIGITS TO
LOWER TEENS. AREAS WITH ANY SNOW COVER COULD SEE SUBZERO SINGLE
DIGIT LOWS...EVERYONE ELSE SHOULD STAY ON THE PLUS SIDE OF ZERO.
HIGH PRESSURE WILL SLIDE EAST ON SATURDAY. TEMPERATURES SHOULD
GRADUALLY MODERATE SATURDAY AFTERNOON INTO SUNDAY AHEAD OF ANOTHER
CONTINENTAL FRONT THAT WILL CROSS THE FORECAST AREA. CONTINUED THE
CHANCE OF SNOW WITH ITS PASSAGE SATURDAY NIGHT INTO SUNDAY. KEPT
LIGHT CHC POPS IN THE WESTERN MOUNTAINS SUNDAY NIGHT INTO MONDAY.
NEXT FRONT ARRIVES ON TUESDAY WITH CHANCE FOR RAIN AND SNOW. LEANED
EARLY NEXT WEEK TOWARDS THE ECMWF WITH ADDITIONAL CLOUDS AND
POPS...WHICH DIVES SYSTEM FURTHER SOUTH WITH COASTAL LOW DEVELOPMENT
COMPARED TO GFS. PLAYED TEMPERATURES CLOSE TO HPCGUIDE.
&&
.AVIATION /23Z TUESDAY THROUGH SUNDAY/...
PRE-FRONTAL TROUGH NOW MOVING INTO THE BLUE RIDGE AHEAD OF FRONT
OVER ERN KY AT 17Z. THE WINDS BEHIND TROF ARE SWITCHING FROM
SOUTHWES TO WEST. THE COLD FRONT WILL MOVE EAST THROUGH BLF/LWB BY
22Z...MAKING IT TO ROANOKE BY 00Z AND LYH/DAN BY 02Z. WINDS ARE
GOING TO GUST UP TO 25-30 KNOTS THIS EVENING FOR A 6 HOUR OR LESS
PERIOD...MAINLY LEE OF THE HIGHLANDS AND ALONG/JUST EAST OF THE
BLUE RIDGE.
FOR BLF/LWB...CIGS WILL DROP TO MVFR WITH FRONTAL PASSAGE WITH
VSBYS DROPPING TO 3-5SM IN LIGHT SNOW SHOWERS. VSBYS WEST OF LWB
AND NORTH OF BLF MAY DROP TO IFR IN HEAVIER SNOW SHOWERS BETWEEN
22Z-03Z THIS EVENING.
CIGS WILL REMAIN MVFR AT BLF/LWB THROUGH DAYBREAK B4 DRIER AIR
SCATTERS OUT THE LOW LVLS. ELSEWHERE...LOOK FOR VFR CIGS OVERNIGHT
THEN CLEARING.
A STRONGER ARCTIC COLD FRONT WILL CROSS THE AREA WEDNESDAY NIGHT
ENHANCING THE THREAT FOR WESTERN MVFR CIGS/VSBYS IN MOUNTAIN SNOW
SHOWERS AND STRONG WINDS AT HIGHER ELEVATIONS THROUGH THURSDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS/WP
NEAR TERM...JJ/WP
SHORT TERM...KM
LONG TERM...KK
AVIATION...AMS/WP
000
FXUS61 KLWX 132242 AAA
AFDLWX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
542 PM EST TUE JAN 13 2009
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE REGION THIS EVENING. HIGH
PRESSURE WILL BUILD OVER THE REGION WEDNESDAY BRINGING DRY AND COLD
CONDITIONS. AN ALBERTA CLIPPER AND ITS ASSOCIATED COLD FRONT WILL
PASS THROUGH WEDNESDAY NIGHT INTO THURSDAY. BITTERLY COLD CONDITIONS
ARE EXPECTED BEHIND THIS SYSTEM THROUGH THE END OF THE WEEK AND
FIRST PART OF THE WEEKEND. ANOTHER SYSTEM MAY AFFECT THE REGION ON
SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
UPDATED TO ADD CLIMATE SECTION CONCERNING THE EXPECTED COLD
CONDITIONS FRIDAY INTO SATURDAY...SEE BELOW...
MID ATLANTIC CONTINUES TO BE LOCATED BETWEEN TWO WEATHER
SYSTEMS EARLY THIS AFTERNOON. ONE WAS LOW PRESSURE OFF THE NORTH
CAROLINA COAST AND THE OTHER WAS LOW PRESSURE ACROSS THE GREAT
LAKES AND ITS ASSOCIATED COLD FRONT APPROACHING THE APPALACHIANS.
LOW PRESSURE OFF THE NORTH CAROLINA COAST HAS HELPED TO BRING A DECK
OF MID TO HIGH CLOUDS INTO THE CWA TODAY. THESE WILL CONTINUE INTO
THIS EVENING BEFORE PUSHING OFFSHORE AS THE COLD FRONT APPROACHING
THE APPALACHIANS THIS AFTERNOON MOVES EAST ACROSS THE CWA THIS
EVENING.
THESE FRONTS NEED TO BE WATCHED. MOST OFTEN...PRECIPITATION IS NOT
ABLE TO MOVE EAST OF THE MTNS...HOWEVER ONCE IN A WHILE A MORE
DYNAMIC ONE IS ABLE TO SQUEEZE OUT A LITTLE MOISTURE FOR A QUICK
BURST OF SNOW OR THE LIKE. DO NOT HAVE A LOT OF MODEL SUPPORT IN
THIS SOLUTION...SO WILL NOT HAVE ANY POPS EAST OF THE MTNS THIS
EVENING. BELIEVE THE MAIN AREA OF PRECIPITATION WILL BE WEST OF THE
MTNS NAMELY THE HIGHLANDS WHICH WILL RECEIVE UPSLOPE ENHANCEMENT
BEHIND THE FRONT AS WINDS TURN WEST NORTHWEST. WINTER WEATHER
ADVISORY IS IN EFFECT FOR 1 TO 2 INCHES OF SNOW ACROSS THE HIGHLANDS.
ACROSS THE ENTIRE CWA...ALONG AND ESPECIALLY BEHIND THE FRONT THERE
WILL BE GUSTY WINDS WHICH MAY REACH 30 KT...WHICH WILL BEGIN TO DRAG
IN COLDER AIR. WIND CHILL VALUES ACROSS THE HIGHLANDS WILL BE AROUND
ZERO LATE AT NIGHT.
&&
.SHORT TERM /WEDNESDAY/...
HIGH PRESSURE BUILDS INTO THE MID ATLANTIC ON WEDNESDAY...BUT ONLY
MAKES A BRIEF APPEARANCE AND IS ALREADY MOVING OFF THE COAST IN
THE AFTERNOON. SNOW SHOWERS IN FAVORED WESTERN UPSLOPE AREAS WILL
CUT OFF EARLY IN THE MORNING. SOME SUNSHINE WILL BE SEEN IN THE
MORNING BUT WILL BE FOLLOWED BY INCREASING CLOUDS IN THE AFTERNOON
AHEAD OF ANOTHER CLIPPER SYSTEM ACROSS THE OHIO VALLEY THAT WILL
MOVE THROUGH AND AFFECT OUR CWA LATER WEDNESDAY NIGHT INTO
THURSDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
AN UPPER-LEVEL LOW OVER EASTERN CANADA WILL REMAIN IN PLACE THROUGH
THE FORECAST PERIOD. THIS WILL CARVE OUT A POTENT MID-LEVEL TROUGH
OVER THE MID-ATLANTIC BRINGING COLD CONDITIONS. SEVERAL DISTURBANCES
WILL ROTATE AROUND THE TROUGH BRINGING CHANCES FOR LIGHT
PRECIPITATION. THE EXACT TIMING AND TRACK OF THESE SYSTEMS REMAINS
UNCERTAIN THIS FAR OUT.
AN ALBERTA CLIPPER WILL PASS THROUGH NORTHERN MARYLAND OVERNIGHT
WEDNESDAY AND THEN QUICKLY OFF THE MID-ATLANTIC COAST THURSDAY. THE
BEST CHANCE FOR SNOW WILL BE ACROSS THE POTOMAC HIGHLANDS...EASTERN
PANHANDLE OF WEST VIRGINIA...AND NEAR THE MASON DIXON LINE. HAVE
KEPT THE HIGHEST POPS AND ACCUMULATING SNOW NEAR THE ALLEGHENY FRONT
WHERE UPSLOPE SNOW WITH THIS SYSTEM IS ALSO EXPECTED. ARCTIC HIGH
PRESSURE WILL APPROACH THE REGION FROM THE NORTHERN PLAINS BEHIND
THIS SYSTEM THURSDAY ALLOWING FOR BITTERLY COLD CONDITIONS BY
THURSDAY NIGHT. LATEST GUIDANCE CONTINUES TO INDICATE LIMITED
INSTABILITY THURSDAY INTO THURSDAY NIGHT BEHIND THE CLIPPER DUE TO
THE STRONG COLD ADVECTION. WILL CONTINUE WITH CHANCE/SLIGHT CHANCE
FOR SNOW SHOWERS ACROSS THE NORTHERN AND WESTERN PORTION OF THE CWA.
HIGHER POPS NEAR THE ALLEGHENY FRONT. TEMPERATURES THURSDAY NIGHT
AND FRIDAY WILL BE AROUND 20-25 DEGREES BELOW CLIMO. THE NORMAL HIGH
AND LOW FOR WASHINGTON DC IS 42 AND 27 DEGREES RESPECTIVELY.
ARCTIC HIGH PRESSURE WILL MOVE OFF THE MID-ATLANTIC COAST SATURDAY
ALLOWING A RETURN FLOW TO SET UP. TEMPERATURES WILL REMAIN WELL
BELOW NORMAL DESPITE THE RETURN FLOW. ANOTHER UPPER-LEVEL
DISTURBANCE AND ITS ASSOCIATED SURFACE LOW WILL TRACK THROUGH THE
REGION SATURDAY NIGHT INTO SUNDAY BRINGING THE CHANCE FOR
PRECIPITATION. BELOW NORMAL TEMPERATURES WILL CONTINUE MONDAY BEHIND
THIS SYSTEM.
BELOW NORMAL TEMPERATURES ARE EXPECTED FOR TUESDAY AS WELL. ANOTHER
DISTURBANCE WILL BRINGING THE CHANCE FOR SNOW. THE EXACT TIMING AND
TRACK OF THIS DISTURBANCE REMAINS UNCERTAIN THIS FAR OUT.
&&
.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
A COLD FRONT WILL MOVE ACROSS THE TERMINALS THIS EVENING. WINDS WILL
BACK TO THE WEST NORTHWEST AND GUST TO 25 TO 30KT ALONG AND
ESPECIALLY BEHIND THE COLD FRONT. HIGH PRESSURE BUILDS IN FOR
WEDNESDAY.
AN AREA OF LOW PRESSURE WILL PASS THROUGH THE TERMINALS OVERNIGHT
WEDNESDAY...THEN OFF THE MID-ATLANTIC COAST THURSDAY. THIS SYSTEM
MAY BRING MVFR CIGS/VSBYS ALONG WITH THE CHANCE FOR LIGHT SNOW
OVERNIGHT WEDNESDAY...ESPECIALLY ACROSS KMRB. GENERALLY VFR
CONDITIONS ARE EXPECTED BEHIND THE SYSTEM THURSDAY...BUT THERE MAY
BE ENOUGH INSTABILITY FOR SCATTERED SNOW SHOWERS ACROSS THE NORTHERN
TERMINALS. GUSTY NORTHWEST WINDS ARE EXPECTED THURSDAY WITH FREQUENT
WIND GUSTS AROUND 30 KNOTS.
HIGH PRESSURE WILL BUILD OVER THE TERMINALS THURSDAY NIGHT THROUGH
FRIDAY NIGHT BRINGING VFR CONDITIONS. A COUPLE DISTURBANCES MAY
AFFECT THE TERMINALS LATER IN THE WEEKEND INTO EARLY NEXT WEEK
BRINGING THE CHANCE FOR PRECIPITATION.
&&
.MARINE...
AS A COLD FRONT MOVES THROUGH THIS EVENING...WINDS WILL INCREASE.
GUSTS ARE EXPECTED TO REACH STRONG SMALL CRAFT ADVISORY CRITERIA /30
KT/ OVERNIGHT. WILL HAVE TO WATCH THE SLIGHT CHANCE THAT GUSTS REACH
MINIMAL GALE WARNING CRITERIA /35 KT/. HIGH PRESSURE BUILDS IN
WEDNESDAY...WITH LESS WIND TOWARD AFTERNOON.
AN AREA OF LOW PRESSURE WILL PASS THROUGH THE WATERS WEDNESDAY
NIGHT. WINDS MAY APPROACH SMALL CRAFT ADVISORY CRITERIA WITH THIS
LOW...ESPECIALLY LATE. WILL CONTINUE WITH A SMALL CRAFT ADVISORY
WEDNESDAY NIGHT. MUCH STRONGER WINDS ARE EXPECTED BEHIND THIS SYSTEM
THURSDAY WHERE A GALE WARNING MAY BE WARRANTED. WINDS WILL DIMINISH
THURSDAY NIGHT...BUT GUSTS AROUND 20 KNOTS ARE STILL EXPECTED.
HIGH PRESSURE WILL BUILD OVER THE WATERS FOR FRIDAY THROUGH
SATURDAY. THE NEXT DISTURBANCE WILL PASS THROUGH THE WATERS SUNDAY.
&&
.CLIMATE...
VERY COLD WEATHER EXPECTED THIS FRIDAY /16 JAN/ INTO SATURDAY
MORNING /17 JAN/. HOWEVER...SINCE THIS IS NEAR THE CLIMATOLOGICALLY
COLDEST TIME OF YEAR...RECORD LOWS AND/OR RECORD LOW MAXIMUM
TEMPERATURES APPEAR UNLIKELY IN THE IMMEDIATE BALTIMORE/WASHINGTON
METROPOLITAN AREA. STILL...IT DOES LOOK TO BE THE COLDEST AIRMASS
FOR THE AREA IN OVER A DECADE. IT WAS NOTABLY COLDER FOR A FEW DAYS
IN MID JANUARY 1994 AT BWI/DCA/IAD.
BELOW ARE THE FORECAST MAXIMA FOR FRIDAY AND THE FORECAST MINIMA FOR
SATURDAY WITH THE MOST RECENT TIMES TEMPERATURES NEARED THESE
LEVELS...AS WELL AS RECORD LOWEST MAX ON 16 JAN AND RECORD LOW ON 17
JAN.
BWI...FRI FCST HIGH: 18 F /HIGHS OF 5-18 F IN MID JAN 1994 AND 19 F
ON JAN 10 2004 AND FEB 4 1996...RECORD LOW MAXIMUM OF 14 F IN 1893/
DCA...FRI JAN 16 FCST HIGH: 20 F /HIGH OF 17 F ON FEB 4 1996 AND 20
F ON FEB 3 1996 AND 21 F ON JAN 10 2004...RECORD LOW MAXIMUM OF 15 F
IN 1893/
IAD...FRI FCST HIGH: 18 F /HIGH OF 14 F ON FEB 4 1996 AND 19 F ON
JAN 17-18 1997 AND 20 ON FEB 5 2007...RECORD LOW MAXIMUM OF 14 IN
1972 AND 1996/
BWI...SAT FCST LOW: 1 F /LOW OF -1 F ON FEB 5 1996 AND 1 F ON JAN 19
1997...RECORD LOW OF -7 IN 1982/
DCA...SAT FCST LOW: 4 F /LOW OF 5 F ON FEB 5 1996...RECORD LOW OF -5
IN 1982/
IAD...SAT FCST LOW: 1 F /LOW OF -1 F ON FEB 7 1995...RECORD LOW OF
-7 IN 1982/
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...WINTER WEATHER ADVISORY UNTIL 4 AM EST WEDNESDAY FOR MDZ501.
VA...WINTER WEATHER ADVISORY UNTIL 4 AM EST WEDNESDAY FOR VAZ021.
WV...WINTER WEATHER ADVISORY UNTIL 4 AM EST WEDNESDAY FOR WVZ054-
501-503.
MARINE...SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 6 AM EST
THURSDAY FOR ANZ530>537.
&&
$$
SYNOPSIS...BPP
NEAR TERM...BPP
SHORT TERM...BPP
LONG TERM...BJL
AVIATION...BJL/BPP
MARINE...BJL/BPP
CLIMATE...BAJ/JRK/KRAMAR
000
FXUS61 KRNK 132101
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
401 PM EST TUE JAN 13 2009
.SYNOPSIS...
A COLD FRONT IS GOING TO MOVE TO THE VIRGINIA COAST TONIGHT WITH A
WEAK HIGH PRESSURE BUILDING IN BRIEFLY WEDNESDAY. AN ARCTIC COLD
FRONT WILL CROSS THE AREA LATE WEDNESDAY NIGHT AND THURSDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
COLD FRONT OVER THE CENTRAL APPS WILL SHIFT EAST THROUGH THE AREA
THIS EVENING. SHORTWAVE OVER THE GULF COAST STATES WILL SHIFT
NORTHEAST INTO THE CAROLINAS THIS EVENING AND INTO CENTRAL VA
OVERNIGHT BEFORE SHEARING INTO THE MID ATLANTIC 12Z WED.
MOISTURE WITH THE FRONT IS NARROW...BUT DEEP ENOUGH THAT ONCE IT
GETS INTO SE WV WILL BRING LIKELY TO CAT SNOW SHOWERS THIS
EVENING. ONCE THE FRONT AND SHORTWAVE MOVE EAST...NW FLOW WILL
CONTINUE BUT MOISTURE BECOMES SHALLOW RATHER FAST. WESTERLY FLOW
WITH PRE-FRONT TROUGH WILL INHIBIT PRECIP FROM MAKING IT EAST OF
THE BLUE RIDGE...EXCEPT A FEW FLURRIES. TRAJECTORIES OVERALL STILL
APPEAR TO LACK A LAKE CONNECTION...EXCEPT FOR A BRIEF PERIOD THIS
EVENING OVER SE WV. LIQUID TO SNOW RATIOS WILL INCREASE TO 20 OR
25 TO 1 BY MIDNIGHT. ATTM...LOOKS LIKE A DUSTING TO ONE INCH
EXPECTED FROM THE WRN SLOPES OF THE NC MTNS THROUGH FAR SW VA INTO
SE WV THRU 12Z WED...WITH 1-3 INCHES EXPECTED OVER THE WRN SLOPES
OF GREENBRIER SOUTH INTO NRN SUMMERS.
TEMPS STARTING OFF CHILL TODAY OUT EAST...ALTHOUGH VSBL SAT
INDICATES THE EWD MOVEMENT TO THE CIRRUS SHIELD SO SOME WARMING
MAY TAKE PLACE FOR 1-2 HOURS. THE MAV MOS LOWS TONIGHT LOOK
REASONABLE...LOOKING AT TEENS IN THE WEST...20S EAST. THE WINDS
BEHIND THE FRONT WILL GUST FOR ABOUT 4-6 HOURS. NOT LOOKING AT
ADVISORY WINDS. AS THE HIGH BUILDS INTO THE AREA WED...WINDS WILL
BECOME LIGHT. THERE WILL BE A SMALL WINDOW OF WIND CHILLS
APPROACHING ZERO TO -5 OVER THE MTNS OF SE WV TOWARD DAWN...AND
MAINLY IN GREENBRIER COUNTY. HAVE HIGHLIGHTED THE SNOW AND WIND
CHILLS IN THE HAZARDOUS WEATHER OUTLOOK.
FOR WED...SHOULD SEE PLENTY OF SUN MOST AREAS...WITH FLOW BECOMING
SW AHEAD OF THE ARCTIC BLAST. WENT GENERALLY WITH MAV MOS FOR
HIGHS. WINDS WILL START TO INCREASE OVER THE SW VA/NW NC MTNS
TOWARD THE LATE AFTERNOON AS 40+ KNOT SW 8H JET PUSHES IN AHEAD OF
FRONT. CLOUDS INCREASE LATE IN THE DAY FROM THE NORTHWEST...BUT
ANY PRECIP WILL HOLD OFF UNTIL WED NIGHT.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
ARCTIC FRONT TO CROSS WEDNESDAY NIGHT WITH THE COLDEST AIR THIS
WINTER. AREA OF LOW PRESSURE TAKES A FAVORABLE TRACK FOR AT LEAST
WIND ADVISORY CRITERIA/HIGH WIND WATCH GUSTS AT THE VERY LEAST
ACROSS SW VA AND NW NC. UNIDIRECTIONAL WINDS...AND THE JET
DIRECTORY OVERHEAD OF ASHE/WATAUGA/GRAYSON...ALONG WITH AN
IMPRESSIVE ISENT OMEGA RISE/FALL COUPLET MAY PRODUCE WIND GUSTS
STRONGER THAN EVEN BUFKIT IS FORECASTING RIGHT NOW. WOULD LIKE TO
SEE MORE DOWNGLIDE FROM AN ISENTROPIC PERSPECTIVE THOUGH. AN EVENT
SIMILAR TO THIS WAS UNDER FORECASTED BY THE MODELS A FEW WEAKS AGO.
AFTER COORD WITH GSP...DECIDED NOT TO HOIST A HIGH WIND WATCH BUT
THIS NEEDS TO BE CONSIDERED LATER FOR WED NIGHT THROUGH THUR
AFTERNOON...BUT MOST LIKELY WHEN THE ARCTIC CROSSES NEAR DAWN
THURSDAY. MIDLEVEL LAPSE RATES AND STRENGTH OF FRONT INDICATE SOME
SNOW SQUALLS POSSIBLY ALONG THE FRONT ACROSS SE WEST VA LATER
WEDNESDAY NIGHT...WITH A QUICK INCH OR TWO ALONG THE FAVORED
SPOTS. ANOTHER INCH OR TWO COULD FALL THURSDAY. ALTHOUGH
FAVORABLE UPSLOPE CONDITIONS WANE THURSDAY...A SHRTWV DROPPING
INTO THE CWA MAY PROVIDE ANOTHER SHOT OF SNOW INTO THE BLUE RIDGE
ON THURSDAY AFTERNOON. SEEMS AS THE 12Z MEX IS FINALLY REALIZING
THE STRENGTH OF THIS AIRMASS...SO GENERALLY FOLLOWED IT ON DAY
4...WHILE UNDERCUTTING MOS LEADING UP TO THAT POINT WITH THE
SHALLOW ARCTIC AIR. A WIND CHIL ADVISORY WILL ALSO BE NEEDED
PERHAPS AS EARLY AS WEDNESDAY NIGHT. IF NO HIGH CLOUDS ARRIVE
FRIDAY NIGHT...AND MOST SPOTS ARE ABLE TO DECOUPLE...AOB 0F IS
POSSIBLE ALONG THE BLUE RIDGE AND INTO SE WEST VA WITH STRONG HIGH
OVERHEAD.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ARCTIC DOME OF HIGH PRESSURE WILL BE LOCATED ACROSS OUR REGION
SATURDAY MORNING WITH VERY COLD READINGS IN THE SINGLE DIGITS TO
LOWER TEENS. AREAS WITH ANY SNOW COVER COULD SEE SUBZERO SINGLE
DIGIT LOWS...EVERYONE ELSE SHOULD STAY ON THE PLUS SIDE OF ZERO.
HIGH PRESSURE WILL SLIDE EAST ON SATURDAY. TEMPERATURES SHOULD
GRADUALLY MODERATE SATURDAY AFTERNOON INTO SUNDAY AHEAD OF ANOTHER
CONTINENTAL FRONT THAT WILL CROSS THE FORECAST AREA. CONTINUED THE
CHANCE OF SNOW WITH ITS PASSAGE SATURDAY NIGHT INTO SUNDAY. KEPT
LIGHT CHC POPS IN THE WESTERN MOUNTAINS SUNDAY NIGHT INTO MONDAY.
NEXT FRONT ARRIVES ON TUESDAY WITH CHANCE FOR RAIN AND SNOW. LEANED
EARLY NEXT WEEK TOWARDS THE ECMWF WITH ADDITIONAL CLOUDS AND
POPS...WHICH DIVES SYSTEM FURTHER SOUTH WITH COASTAL LOW DEVELOPMENT
COMPARED TO GFS. PLAYED TEMPERATURES CLOSE TO HPCGUIDE.
&&
.AVIATION /21Z TUESDAY THROUGH SUNDAY/...
PRE-FRONTAL TROUGH NOW MOVING INTO THE BLUE RIDGE AHEAD OF FRONT
OVER ERN KY AT 17Z. THE WINDS BEHIND TROF ARE SWITCHING FROM
SOUTHWES TO WEST. THE COLD FRONT WILL MOVE EAST THROUGH BLF/LWB BY
22Z...MAKING IT TO ROANOKE BY 00Z AND LYH/DAN BY 02Z. WINDS ARE
GOING TO GUST UP TO 25-30 KNOTS THIS EVENING FOR A 6 HOUR OR LESS
PERIOD...MAINLY LEE OF THE HIGHLANDS AND ALONG/JUST EAST OF THE
BLUE RIDGE.
FOR BLF/LWB...CIGS WILL DROP TO MVFR WITH FRONTAL PASSAGE WITH
VSBYS DROPPING TO 3-5SM IN LIGHT SNOW SHOWERS. VSBYS WEST OF LWB
AND NORTH OF BLF MAY DROP TO IFR IN HEAVIER SNOW SHOWERS BETWEEN
22Z-03Z THIS EVENING.
CIGS WILL REMAIN MVFR AT BLF/LWB THROUGH DAYBREAK B4 DRIER AIR
SCATTERS OUT THE LOW LVLS. ELSEWHERE...LOOK FOR VFR CIGS OVERNIGHT
THEN CLEARING.
A STRONGER ARCTIC COLD FRONT WILL CROSS THE AREA WEDNESDAY NIGHT
ENHANCING THE THREAT FOR WESTERN MVFR CIGS/VSBYS IN MOUNTAIN SNOW
SHOWERS AND STRONG WINDS AT HIGHER ELEVATIONS THROUGH THURSDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS/WP
NEAR TERM...WP
SHORT TERM...KM
LONG TERM...KK
AVIATION...AMS/WP
000
FXUS61 KAKQ 132021
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
321 PM EST TUE JAN 13 2009
.SYNOPSIS...
LOW PRESSURE OFF THE SOUTHEASTERN COAST WILL STRENGTHEN AS IT
MOVES ALONG THE SOUTHEASTERN COAST...PUSHING AWAY FROM THE REGION
BY THIS EVENING. HIGH PRESSURE BRIEFLY BUILDS IN FROM THE
SOUTHWEST ON WEDNESDAY...WITH A STRONG COLD FRONT CROSSING THE
REGION ON THURSDAY. ARCTIC HIGH PRESSURE WILL USHER IN A COLD
AIRMASS FRIDAY INTO SATURDAY.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
FRONT JUST WEST OF OUR COUNTIES THIS AFTERNOON. DRY SLOT OVER THE
PIEDMONT HAS INHIBITED ANY PRECIP FROM DVLPG...BUT SUFFICIENT MID
AND HIGH CLOUD CVR HAS KEPT TEMPS DOWN IN THE UPR 30S TO LWR 40S
CURRENTLY. MAINLY LGT RAIN CONTINUING OVER OUR SE COUNTIES WITH SFC
LOW OFFSHORE NOW EAST OF CNTRL NC COAST. MODELS IN GOOD AGREEMENT IN
QUICKLY MVG THIS LOW TO THE NNE THIS EVNG...SO PRECIP SHOULD MOVE
OFFSHORE BEFORE MIDNIGHT AND SKIES WILL CLEAR FROM WEST TO EAST
TONIGHT THROUGH THE EARLY MORNING HRS. TEMPS WON`T BE MUCH DIFFERENT
THAN THIS MORNING`S LOWS DUE TO LINGERING CLOUD CVR.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY NIGHT/...
DRY CONDS START OUT THE DAY ON WEDNESDAY AS THE FRONT CONTINUES TO
PUSH OFFSHORE AND WEAK HIGH PRESSURE BUILDS IN. EVEN WITH CLEAR
SKIES TO START OUT THE DAY...CAA AND INCREASING CLOUDS WILL KEEP MAX
TEMPS DOWN IN THE MID 30S (WEST AND NORTH WHERE THEY`LL SEE CLOUDS
SOONER IN THE DAY) TO AROUND 40 DEGREES IN THE SOUTH/SOUTHEAST
AREAS. ANOTHER FAST MVG SYSTEM MVS TOWARDS THE AREA IN THE AFTN/EVNG
HRS BUT HIGH TO OUR SE WILL KEEP THE LOW TO OUR NORTH. HAVE
CONTINUED ONLY SILENT POPS WITH THIS SYSTEM DUE TO LACK OF MOISTURE
AND THE FACT TAHT MOST OF THE ENERGY REMAINS TO OUR NORTH. SHOULD
STILL SEE PLENTY OF CLOUDS WED NIGHT INTO THURS WITH THIS FEATURE
HOWEVER.
TROUGH MVS OVER THE EAST COAST THURS NIGHT/FRI MORNING...SO A BIG
CHANGE EXPECTED GOING INTO FRIDAY MORNING. CLEARING SKIES THURS
NIGHT ALONG WITH LIGHT WINDS AND STRONG CAA WILL ALLOW TEMPS TO DROP
INTO THE TEENS MOST LOCATIONS. GUIDANCE HAS BEEN TRENDING COLDER AND
THEREFORE HAVE DROPPED MINS A FEW DEGREES FROM PREVIOUS FCST. STRONG
HIGH BUILDS INTO THE OH VALLEY ON FRIDAY...KEEPING MAX TEMPS DOWN
BLO FREEZING AND MOCLEAR SKIES OVER THE AREA.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
HIGH PRES BUILDS IN FROM THE W FRI NIGHT THRU SAT NIGHT. FRIGID LOW
TEMPS WILL CONT FRI NIGHT...ONLY NEAR 10 NW/N TO NEAR 20 SE. TEMPS
START TO MODERATE ON SAT AS THE FLOW BECOMES SW WITH THE HIGH
SLIDING OFFSHORE. HIGHS `WARM` SAT INTO THE LWR TO MID 30S. LOWS
ALSO MILDER SAT NIGHT...NEAR 20 NW TO NEAR 30 SE.
SEVERAL TROFS/AREAS OF LOW PRES WILL THEN ROTATE THRU THE MID-
ATLANTIC FROM SUN THRU EARLY NEXT WEEK. FCST MODEL SOUNDINGS SHOW
PLENTY OF DRY AIR IN PLACE AS EACH TROF MOVES THRU...AND GIVEN THE
TRAJECTORY OF EACH WAVE EXPECT THAT IT WILL BE DIFFICULT TO GET MUCH
IF ANY MEASURABLE PRECIP OUT OF THESE FEATURES. IF MODELS START TO
TREND WITH A TRACK FARTHER TO THE S THEN WILL NEED TO INCREASE THE
CHANCE OF PRECIP. WILL KEEP POPS CAPPED BETWEEN 20-30% AT THIS TIME.
AT ANY RATE...COLD AIR WILL REMAIN IN PLACE THRU AT LEAST EARLY NEXT
WEEK (ALTHO NOT AS COLD AS FRI-SAT). HIGHS WILL BE IN THE UPR 30S
NW/N TO MID 40S SE...LOWS IN THE LWR 20S NW/N TO NEAR 30 SE.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
A LOW PRESSURE SYSTEM WAS CENTERED ABOUT 40 MILES S OF CAPE
LOOKOUT NC AT 17Z. LIGHT RAIN HAS BROKEN OUT ACROSS ERN NC AND FAR
SE VA. CEILINGS HAVE LOWERED AT THE TAF SITES WITH IFR AT ECG AND MVFR
PRESENT OR SOON TO DEVELOP AT THE OTHER TAF SITES. AS THE LOW
MOVES OFF TO THE NE...RAIN WILL END AROUND 00Z. VFR CONDITIONS
WILL DEVELOP TONIGHT AND CONTINUE WED AS HIGH PRESSURE BUILDS
INTO THE AREA.
VFR CONDITIONS WILL PREVAIL DURING THE NEXT SEVERAL DAYS. WINDS
WILL BE GUSTY AT TIMES THU AS AN ARCTIC COLD FRONT CROSSES THE
AREA. A LOW PRESSURE SYSTEM MAY IMPACT THE AREA SUN WITH A CHANCE
OF PRECIPITATION AND POSSIBLY LOWERING AVIATION CONDITIONS.
&&
.MARINE...
AN AREA OF LOW PRES WILL CONTINUE TO DEVELOP/DEEPEN OFF THE NC OBX.
THE LOW WILL MOVE TO THE NE AND AWAY FROM THE COAST TONIGHT...AS A
COLD FRONT SWEEPS IN FROM THE W. WINDS/SEAS WILL INCREASE/BUILD
LATER THIS EVENING...AND SCA FLAGS REMAIN IN EFFECT...BEGINNING AT
03Z TONIGHT. WINDS WILL BE THE STRONGEST OVER THE NRN WATERS COASTAL
WATERS FROM CAPE CHARLES LIGHT VA NORTHWARD...AND HAVE GALE WARNINGS
IN EFFECT FOR THOSE ZONES. ONLY EXPECT ABOUT A 6 HR WINDOW FOR GALE
FORCE WINDS TO OCCUR...FROM MIDNIGHT THRU SUNRISE. AFTERWARD WINDS
WILL START TO DIMINISH AND SEAS WILL SLOWLY SUBSIDE AS HIGH PRES
BRIEFLY BUILDS IN FROM THE W ON WED.
ANOTHER AREA OF LOW PRES WILL MOVE ACROSS THE MID-ATLANTIC FROM THE
W WED NIGHT THRU THU...AND HIGH END SCA TO LOW END GALE CONDITIONS
ARE EXPECTED YET AGAIN. HIGH PRES RETURNS LATE FRI THRU SAT
NIGHT...WITH ANOTHER LOW PRES SYSTEM AFFECTING THE REGION BY THE END
OF THE WEEKEND INTO EARLY NEXT WEEK.
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 1 PM EST
WEDNESDAY FOR ANZ630>633-656-658.
GALE WARNING FROM 1 AM TO 7 AM EST WEDNESDAY FOR ANZ650-652-
654.
&&
$$
SYNOPSIS...JYM
NEAR TERM...JYM
SHORT TERM...JYM
LONG TERM...JRL
AVIATION...LSA
MARINE...JRL
000
FXUS61 KLWX 131946
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
246 PM EST TUE JAN 13 2009
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE REGION THIS EVENING. HIGH
PRESSURE WILL BUILD OVER THE REGION WEDNESDAY BRINGING DRY AND COLD
CONDITIONS. AN ALBERTA CLIPPER AND ITS ASSOCIATED COLD FRONT WILL
PASS THROUGH WEDNESDAY NIGHT INTO THURSDAY. BITTERLY COLD CONDITIONS
ARE EXPECTED BEHIND THIS SYSTEM THROUGH THE END OF THE WEEK AND
FIRST PART OF THE WEEKEND. ANOTHER SYSTEM MAY AFFECT THE REGION ON
SUNDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
MID ATLANTIC CONTINUES TO BE LOCATED BETWEEN TWO WEATHER SYSTEMS
EARLY THIS AFTERNOON. ONE WAS LOW PRESSURE OFF THE NORTH CAROLINA
COAST AND THE OTHER WAS LOW PRESSURE ACROSS THE GREAT LAKES AND ITS
ASSOCIATED COLD FRONT APPROACHING THE APPALACHIANS.
LOW PRESSURE OFF THE NORTH CAROLINA COAST HAS HELPED TO BRING A DECK
OF MID TO HIGH CLOUDS INTO THE CWA TODAY. THESE WILL CONTINUE INTO
THIS EVENING BEFORE PUSHING OFFSHORE AS THE COLD FRONT APPROACHING
THE APPALACHIANS THIS AFTERNOON MOVES EAST ACROSS THE CWA THIS
EVENING.
THESE FRONTS NEED TO BE WATCHED. MOST OFTEN...PRECIPITATION IS NOT
ABLE TO MOVE EAST OF THE MTNS...HOWEVER ONCE IN A WHILE A MORE
DYNAMIC ONE IS ABLE TO SQUEEZE OUT A LITTLE MOISTURE FOR A QUICK
BURST OF SNOW OR THE LIKE. DO NOT HAVE A LOT OF MODEL SUPPORT IN
THIS SOLUTION...SO WILL NOT HAVE ANY POPS EAST OF THE MTNS THIS
EVENING. BELIEVE THE MAIN AREA OF PRECIPITATION WILL BE WEST OF THE
MTNS NAMELY THE HIGHLANDS WHICH WILL RECEIVE UPSLOPE ENHANCEMENT
BEHIND THE FRONT AS WINDS TURN WEST NORTHWEST. WINTER WEATHER
ADVISORY IS IN EFFECT FOR 1 TO 2 INCHES OF SNOW ACROSS THE HIGHLANDS.
ACROSS THE ENTIRE CWA...ALONG AND ESPECIALLY BEHIND THE FRONT THERE
WILL BE GUSTY WINDS WHICH MAY REACH 30 KT...WHICH WILL BEGIN TO DRAG
IN COLDER AIR. WIND CHILL VALUES ACROSS THE HIGHLANDS WILL BE AROUND
ZERO LATE AT NIGHT.
&&
.SHORT TERM /WEDNESDAY/...
HIGH PRESSURE BUILDS INTO THE MID ATLANTIC ON WEDNESDAY...BUT ONLY
MAKES A BRIEF APPEARANCE AND IS ALREADY MOVING OFF THE COAST IN THE
AFTERNOON. SNOW SHOWERS IN FAVORED WESTERN UPSLOPE AREAS WILL CUT
OFF EARLY IN THE MORNING. SOME SUNSHINE WILL BE SEEN IN THE MORNING
BUT WILL BE FOLLOWED BY INCREASING CLOUDS IN THE AFTERNOON AHEAD OF
ANOTHER CLIPPER SYSTEM ACROSS THE OHIO VALLEY THAT WILL MOVE THROUGH
AND AFFECT OUR CWA LATER WEDNESDAY NIGHT INTO THURSDAY.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
AN UPPER-LEVEL LOW OVER EASTERN CANADA WILL REMAIN IN PLACE THROUGH
THE FORECAST PERIOD. THIS WILL CARVE OUT A POTENT MID-LEVEL TROUGH
OVER THE MID-ATLANTIC BRINGING COLD CONDITIONS. SEVERAL DISTURBANCES
WILL ROTATE AROUND THE TROUGH BRINGING CHANCES FOR LIGHT
PRECIPITATION. THE EXACT TIMING AND TRACK OF THESE SYSTEMS REMAINS
UNCERTAIN THIS FAR OUT.
AN ALBERTA CLIPPER WILL PASS THROUGH NORTHERN MARYLAND OVERNIGHT
WEDNESDAY AND THEN QUICKLY OFF THE MID-ATLANTIC COAST THURSDAY. THE
BEST CHANCE FOR SNOW WILL BE ACROSS THE POTOMAC HIGHLANDS...EASTERN
PANHANDLE OF WEST VIRGINIA...AND NEAR THE MASON DIXON LINE. HAVE
KEPT THE HIGHEST POPS AND ACCUMULATING SNOW NEAR THE ALLEGHENY FRONT
WHERE UPSLOPE SNOW WITH THIS SYSTEM IS ALSO EXPECTED. ARCTIC HIGH
PRESSURE WILL APPROACH THE REGION FROM THE NORTHERN PLAINS BEHIND
THIS SYSTEM THURSDAY ALLOWING FOR BITTERLY COLD CONDITIONS BY
THURSDAY NIGHT. LATEST GUIDANCE CONTINUES TO INDICATE LIMITED
INSTABILITY THURSDAY INTO THURSDAY NIGHT BEHIND THE CLIPPER DUE TO
THE STRONG COLD ADVECTION. WILL CONTINUE WITH CHANCE/SLIGHT CHANCE
FOR SNOW SHOWERS ACROSS THE NORTHERN AND WESTERN PORTION OF THE CWA.
HIGHER POPS NEAR THE ALLEGHENY FRONT. TEMPERATURES THURSDAY NIGHT
AND FRIDAY WILL BE AROUND 20-25 DEGREES BELOW CLIMO. THE NORMAL HIGH
AND LOW FOR WASHINGTON DC IS 42 AND 27 DEGREES RESPECTIVELY.
ARCTIC HIGH PRESSURE WILL MOVE OFF THE MID-ATLANTIC COAST SATURDAY
ALLOWING A RETURN FLOW TO SET UP. TEMPERATURES WILL REMAIN WELL
BELOW NORMAL DESPITE THE RETURN FLOW. ANOTHER UPPER-LEVEL
DISTURBANCE AND ITS ASSOCIATED SURFACE LOW WILL TRACK THROUGH THE
REGION SATURDAY NIGHT INTO SUNDAY BRINGING THE CHANCE FOR
PRECIPITATION. BELOW NORMAL TEMPERATURES WILL CONTINUE MONDAY BEHIND
THIS SYSTEM.
BELOW NORMAL TEMPERATURES ARE EXPECTED FOR TUESDAY AS WELL. ANOTHER
DISTURBANCE WILL BRINGING THE CHANCE FOR SNOW. THE EXACT TIMING AND
TRACK OF THIS DISTURBANCE REMAINS UNCERTAIN THIS FAR OUT.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
A COLD FRONT WILL MOVE ACROSS THE TERMINALS THIS EVENING. WINDS WILL
BACK TO THE WEST NORTHWEST AND GUST TO 25 TO 30KT ALONG AND
ESPECIALLY BEHIND THE COLD FRONT. HIGH PRESSURE BUILDS IN FOR
WEDNESDAY.
AN AREA OF LOW PRESSURE WILL PASS THROUGH THE TERMINALS OVERNIGHT
WEDNESDAY...THEN OFF THE MID-ATLANTIC COAST THURSDAY. THIS SYSTEM
MAY BRING MVFR CIGS/VSBYS ALONG WITH THE CHANCE FOR LIGHT SNOW
OVERNIGHT WEDNESDAY...ESPECIALLY ACROSS KMRB. GENERALLY VFR
CONDITIONS ARE EXPECTED BEHIND THE SYSTEM THURSDAY...BUT THERE MAY
BE ENOUGH INSTABILITY FOR SCATTERED SNOW SHOWERS ACROSS THE NORTHERN
TERMINALS. GUSTY NORTHWEST WINDS ARE EXPECTED THURSDAY WITH FREQUENT
WIND GUSTS AROUND 30 KNOTS.
HIGH PRESSURE WILL BUILD OVER THE TERMINALS THURSDAY NIGHT THROUGH
FRIDAY NIGHT BRINGING VFR CONDITIONS. A COUPLE DISTURBANCES MAY
AFFECT THE TERMINALS LATER IN THE WEEKEND INTO EARLY NEXT WEEK
BRINGING THE CHANCE FOR PRECIPITATION.
&&
.MARINE...
AS A COLD FRONT MOVES THROUGH THIS EVENING...WINDS WILL INCREASE.
GUSTS ARE EXPECTED TO REACH STRONG SMALL CRAFT ADVISORY CRITERIA /30
KT/ OVERNIGHT. WILL HAVE TO WATCH THE SLIGHT CHANCE THAT GUSTS REACH
MINIMAL GALE WARNING CRITERIA /35 KT/. HIGH PRESSURE BUILDS IN
WEDNESDAY...WITH LESS WIND TOWARD AFTERNOON.
AN AREA OF LOW PRESSURE WILL PASS THROUGH THE WATERS WEDNESDAY
NIGHT. WINDS MAY APPROACH SMALL CRAFT ADVISORY CRITERIA WITH THIS
LOW...ESPECIALLY LATE. WILL CONTINUE WITH A SMALL CRAFT ADVISORY
WEDNESDAY NIGHT. MUCH STRONGER WINDS ARE EXPECTED BEHIND THIS SYSTEM
THURSDAY WHERE A GALE WARNING MAY BE WARRANTED. WINDS WILL DIMINISH
THURSDAY NIGHT...BUT GUSTS AROUND 20 KNOTS ARE STILL EXPECTED.
HIGH PRESSURE WILL BUILD OVER THE WATERS FOR FRIDAY THROUGH
SATURDAY. THE NEXT DISTURBANCE WILL PASS THROUGH THE WATERS SUNDAY.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...WINTER WEATHER ADVISORY UNTIL 4 AM EST WEDNESDAY FOR MDZ501.
VA...WINTER WEATHER ADVISORY UNTIL 4 AM EST WEDNESDAY FOR VAZ021.
WV...WINTER WEATHER ADVISORY UNTIL 4 AM EST WEDNESDAY FOR WVZ054-
501-503.
MARINE...SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 6 AM EST
THURSDAY FOR ANZ530>537.
&&
$$
SYNOPSIS...PELOQUIN
NEAR TERM...PELOQUIN
SHORT TERM...PELOQUIN
LONG TERM...BJL
AVIATION...PELOQUIN/BJL
MARINE...PELOQUIN/BJL
000
FXUS61 KRNK 131913
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
213 PM EST TUE JAN 13 2009
.SYNOPSIS...
A COLD FRONT IS GOING TO MOVE TO THE VIRGINIA COAST TONIGHT WITH A
WEAK HIGH PRESSURE BUILDIN IN BRIEFLY WEDNESDAY. AN ARCTIC COLD
FRONT WILL CROSS THE AREA LATE WEDNESDAY NIGHT AND THURSDAY.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
COLD FRONT OVER THE CENTRAL APPS WILL SHIFT EAST THROUGH THE AREA
THIS EVENING. SHORTWAVE OVER THE GULF COAST STATES WILL SHIFT
NORTHEAST INTO THE CAROLINAS THIS EVENING AND INTO CENTRAL VA
OVERNIGHT BEFORE SHEARING INTO THE MID ATLANTIC 12Z WED.
MOISTURE WITH THE FRONT IS NARROW...BUT DEEP ENOUGH THAT ONCE IT
GETS INTO SE WV WILL BRING LIKELY TO CAT SNOW SHOWERS THIS
EVENING. ONCE THE FRONT AND SHORTWAVE MOVE EAST...NW FLOW WILL
CONTINUE BUT MOISTURE BECOMES SHALLOW RATHER FAST. WESTERLY FLOW
WITH PRE-FRONT TROUGH WILL INHIBIT PRECIP FROM MAKING IT EAST OF
THE BLUE RIDGE...EXCEPT A FEW FLURRIES. TRAJECTORIES OVERALL STILL
APPEAR TO LACK A LAKE CONNECTION...EXCEPT FOR A BRIEF PERIOD THIS
EVENING OVER SE WV. LIQUID TO SNOW RATIOS WILL INCREASE TO 20 OR
25 TO 1 BY MIDNIGHT. ATTM...LOOKS LIKE A DUSTING TO ONE INCH
EXPECTED FROM THE WRN SLOPES OF THE NC MTNS THROUGH FAR SW VA INTO
SE WV THRU 12Z WED...WITH 1-3 INCHES EXPECTED OVER THE WRN SLOPES
OF GREENBRIER SOUTH INTO NRN SUMMERS.
TEMPS STARTING OFF CHILL TODAY OUT EAST...ALTHOUGH VSBL SAT
INDICATES THE EWD MOVEMENT TO THE CIRRUS SHIELD SO SOME WARMING
MAY TAKE PLACE FOR 1-2 HOURS. THE MAV MOS LOWS TONIGHT LOOK
REASONABLE...LOOKING AT TEENS IN THE WEST...20S EAST. THE WINDS
BEHIND THE FRONT WILL GUST FOR ABOUT 4-6 HOURS. NOT LOOKING AT
ADVISORY WINDS. AS THE HIGH BUILDS INTO THE AREA WED...WINDS WILL
BECOME LIGHT. THERE WILL BE A SMALL WINDOW OF WIND CHILLS
APPROACHING ZERO TO -5 OVER THE MTNS OF SE WV TOWARD DAWN...AND
MAINLY IN GREENBRIER COUNTY. HAVE HIGHLIGHTED THE SNOW AND WIND
CHILLS IN THE HAZARDOUS WEATHER OUTLOOK.
FOR WED...SHOULD SEE PLENTY OF SUN MOST AREAS...WITH FLOW BECOMING
SW AHEAD OF THE ARCTIC BLAST. WENT GENERALLY WITH MAV MOS FOR
HIGHS. WINDS WILL START TO INCREASE OVER THE SW VA/NW NC MTNS
TOWARD THE LATE AFTERNOON AS 40+ KNOT SW 8H JET PUSHES IN AHEAD OF
FRONT. CLOUDS INCREASE LATE IN THE DAY FROM THE NORTHWEST...BUT
ANY PRECIP WILL HOLD OFF UNTIL WED NIGHT.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
ON WEDNESDAY...THE HIGH PRESSURE MAKES A BRIEF VISIT TO THE
REGION...PROVIDING FOR PLENTY OF SUNSHINE...EVEN IN THE
MOUNTAINS...AND LIGHT WINDS. THE AIR BEHIND TODAYS COLD FRONT WILL
BE COLDER...BUT NOT SIGNIFICANTLY. HIGHS ON WEDNESDAY STILL SHOULD BE
IN THE MID-UPPER 30S IN THE MOUNTAINS AND LOW 40S EAST OF THE BLUE
RIDGE.
THE ONSET OF THE MUCH COLDER AIR WILL BEGIN WEDNESDAY NIGHT AS A
MUCH STRONGER COLD FRONT MOVES THROUGH THE REGION. UPSLOPE SNOW
SHOWERS IN THE MOUNTAINS WILL BE ON THE INCREASE THROUGH THE NIGHT.
GOOD PRESSURE RISES ALONG WITH GOOD COLD AIR ADVECTION BEHIND THE
FRONT WILL ALLOW FOR GUSTY WINDS IN THE MOUNTAINS. THE NORTHERN
MOUNTAINS OF NORTH CAROLINA AND THE NEIGHBORING MOUNTAIN EMPIRE
REGION OF SOUTHWEST VIRGINIA MAY SEE GUSTS AROUND 40 MPH BY DAYBREAK
THURSDAY.
ON THURSDAY UPSLOPE SNOW SHOWERS WILL CONTINUE...BUT COVERAGE WILL
GRADUALLY BE ON THE DECREASE. HIGH TEMPERATURES IN THE MOUNTAINS
WILL BE ONLY A FEW DEGREES HIGHER THAN MORNING LOWS. EAST OF THE
BLUE RIDGE..WE MAY SEE HIGHS 5 TO 8 DEGREES HIGHER THAN MORNINGS
LOWS. THE PRESSURE GRADIENT WILL WEAKEN A LITTLE THROUGH THE DAY AS
WELL...SO WIND SPEEDS ALSO WILL DECREASE SLOWLY THROUGH THE DAY.
THURSDAY NIGHT TEMPERATURES WILL CONTINUE TO FALL WITH READINGS BY
DAYBREAK THURSDAY IN THE SINGLE DIGITS IN THE MOUNTAINS...WITH
VALUES JUST A LITTLE ABOVE 10 EAST OF THE BLUE RIDGE. WINDS STILL
SHOULD BE IN THE 10 TO 15 MPH RANGE IN THE MOUNTAINS. THE
COMBINATION OF THE COLD TEMPERATURES AND THESE WINDS WILL ALLOW THE
WIND CHILL READING TO FALL BELOW WIND CHILL ADVISORY CRITERIA. WILL
CONTINUE TO HIGHLIGHT THIS CONCERN IN THE HAZARDOUS WEATHER OUTLOOK.
ARCTIC DOME OF HIGH PRESSURE (1040+ MB) WILL PASS OVERHEAD FRIDAY
BRINGING VERY COLD AND DRY AIRMASS ACROSS THE FORECAST AREA...85H
TEMPS M18 TO M24 DEG C. SURFACE TEMPS FRIDAY WILL BE HARD PRESSED
TO GET OUT OF THE TEENS MOUNTAINS...20S EAST OF THE BLUE RIDGE.
THIS WILL SET STAGE FOR SINGLE DIGIT LOWS FRIDAY NIGHT. AREAS WITH
ANY SNOW COVER WILL LIKELY SEE SUBZERO SINGLE DIGIT LOWS...EVERYONE
ELSE SHOULD STAY ON THE PLUS SIDE OF ZERO.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
ARCTIC DOME OF HIGH PRESSURE WILL BE LOCATED ACROSS OUR REGION
SATURDAY MORNING WITH VERY COLD READINGS IN THE SINGLE DIGITS TO
LOWER TEENS. AREAS WITH ANY SNOW COVER COULD SEE SUBZERO SINGLE
DIGIT LOWS...EVERYONE ELSE SHOULD STAY ON THE PLUS SIDE OF ZERO.
HIGH PRESSURE WILL SLIDE EAST ON SATURDAY. TEMPERATURES SHOULD
GRADUALLY MODERATE SATURDAY AFTERNOON INTO SUNDAY AHEAD OF ANOTHER
CONTINENTAL FRONT THAT WILL CROSS THE FORECAST AREA. CONTINUED THE
CHANCE OF SNOW WITH ITS PASSAGE SATURDAY NIGHT INTO SUNDAY. KEPT
LIGHT CHC POPS IN THE WESTERN MOUNTAINS SUNDAY NIGHT INTO MONDAY.
NEXT FRONT ARRIVES ON TUESDAY WITH CHANCE FOR RAIN AND SNOW. LEANED
EARLY NEXT WEEK TOWARDS THE ECMWF WITH ADDITIONAL CLOUDS AND
POPS...WHICH DIVES SYSTEM FURTHER SOUTH WITH COASTAL LOW DEVELOPMENT
COMPARED TO GFS. PLAYED TEMPERATURES CLOSE TO HPCGUIDE.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
PRE-FRONTAL TROUGH NOW MOVING INTO THE BLUE RIDGE AHEAD OF FRONT
OVER ERN KY AT 17Z. THE WINDS BEHIND TROF ARE SWITCHING FROM
SOUTHWES TO WEST. THE COLD FRONT WILL MOVE EAST THROUGH BLF/LWB BY
22Z...MAKING IT TO ROANOKE BY 00Z AND LYH/DAN BY 02Z. WINDS ARE
GOING TO GUST UP TO 25-30 KNOTS THIS EVENING FOR A 6 HOUR OR LESS
PERIOD...MAINLY LEE OF THE HIGHLANDS AND ALONG/JUST EAST OF THE
BLUE RIDGE.
FOR BLF/LWB...CIGS WILL DROP TO MVFR WITH FRONTAL PASSAGE WITH
VSBYS DROPPING TO 3-5SM IN LIGHT SNOW SHOWERS. VSBYS WEST OF LWB
AND NORTH OF BLF MAY DROP TO IFR IN HEAVIER SNOW SHOWERS BETWEEN
22Z-03Z THIS EVENING.
CIGS WILL REMAIN MVFR AT BLF/LWB THROUGH DAYBREAK B4 DRIER AIR
SCATTERS OUT THE LOW LVLS. ELSEWHERE...LOOK FOR VFR CIGS OVERNIGHT
THEN CLEARING.
A STRONGER ARCTIC COLD FRONT WILL CROSS THE AREA WEDNESDAY NIGHT
ENHANCING THE THREAT FOR WESTERN MVFR CIGS/VSBYS IN MOUNTAIN SNOW
SHOWERS AND STRONG WINDS AT HIGHER ELEVATIONS THROUGH THURSDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS/WP
NEAR TERM...WP
SHORT TERM...DS
LONG TERM...KK
AVIATION...AMS/WP
000
FXUS61 KAKQ 131821
AFDAKQ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
121 PM EST TUE JAN 13 2009
.SYNOPSIS...
LOW PRESSURE OFF THE SOUTHEASTERN COAST WILL STRENGTHEN AS IT
MOVES ALONG THE SOUTHEASTERN COAST...PUSHING AWAY FROM THE REGION
BY THIS EVENING. HIGH PRESSURE BRIEFLY BUILDS IN FROM THE
SOUTHWEST ON WEDNESDAY...WITH A STRONG COLD FRONT CROSSING THE
REGION ON THURSDAY. ARCTIC HIGH PRESSURE WILL USHER IN A COLD
AIRMASS FRIDAY INTO SATURDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
EARLY MORNING ANALYSIS DEPICTS SFC HIGH PRESSURE OFF THE MID ATL COAST.
FARTHER WEST...DEEPENING LOW PRESSURE WAS ANALYZED OVER MI...WITH
THE ASSOCIATED COLD FRONT DIVING SOUTH AND WEST INTO THE LWR MS
VLY. TO THE WEST...ELONGATED AREA OF SFC HIGH PRES WAS NOTED OVER
ONTARIO/MANITOBA...SPILLING SOUTH ONTO THE PLAINS AND MO VLY.
AS EXPECTED...LTL MORE THAN A BATCH OF CI BISECTING NW HALF OF THE
CWA THIS MORNING. MORE SUBSTANTIVE CLDS IN ASSN WITH DEVELOPING
ISENTROPIC LIFT (290-300K SFC) FOLLOWING APPROACHING UPR LVL
TROF...AND JUST NOSING INTO NE NC COUNTIES THIS MORNING. GENERAL
TREND OF INCREASING CLDS TO CONTINUE THROUGH MIDDAY ALONG AND
EAST OF A LINE FROM ASJ-JGG-OXB THIS MORNING.
SLIGHTLY LESS AGGRESSIVE NAM SOLN VERIFYING JUST A BIT BETTER
THIS MORNING...WITH RAIN SHIELD STILL OFF THE GA/SC COAST. MODELS
HV COME INTO BETTER AGREEMENT ON A BIT OF A SLOWER TRACK. CURRENT
THINKING TAKES DEVELOPING SFC LOW JUST EAST OF CAPE HATTERAS BY
MIDDAY...WELL OFFSHORE BY LT TONIGHT. ACCORDINGLY...HV PUSHED POPS
BACK A LTL BIT GIVEN WHAT ARE STILL RELATIVELY DRY SOUNDINGS
ACROSS SERN CWA. CONSIDERING THE AFOREMENTIONED TRACK...STILL DO
BELIEVE SOME LGT RAIN WL PUSH INTO SERN CWA AFTER 12-14Z. HI
CHC/LKLY POPS NOW MID TO LT MORNING ACROSS TIDEWATER RGN...RISING TO
LKLY/CATEGORICAL POPS INTO THE AFTERNOON. INLAND...HV CUT BACK ON
POPS TO SILENT OR LESS WEST OF I-95...ALLOWING FOR A BUFFER OF
SLIGHT CHC POPS JUST EAST OF I-95. HOWEVER...WITH BUFKIT SOUNDINGS
STILL TICKING WITH PLENTY OF LLVL DRY AIR OVER THIS REGION...THINK
MOST IF NOT ALL OF THE DAY WL BE DRY WEST OF THAT AFOREMENTIONED ASJ-
JGG-OXB LINE.
AS TO QPF...AMTS WILL SHOW A SHARP GRDNT...WITH SREF PLUMES
SUGGESTING HALF TO THREE-QUARTERS OF AN INCH ACROSS THE OUTER
BANK....WITH A QUARTER INCH OR LESS ELSEWHERE ACROSS TIDEWATER AND
LWR EASTERN SHORE. HIGHS TODAY ARE A BIT TRICKY. WL GO WITH HIGHS
AROUND 50 GIVEN WAA AND ONSHORE FLOW...WITH SLIGHTLY COOLER M40S
INLAND. HOWEVER...HV BUMPED HIGHS A BIT HIGHER OVER THE NERN
PIEDMONT WITH PLENTY OF LLVL DRY AIR AND PSNY SKIES.
GRADUAL CLEARING TONIGHT...AND POPS SHUT OFF QUICKLY AFTER
MIDNIGHT TONIGHT AS OVERRUNNING WANES AND LOW DEPARTS OVERNIGHT.
MODIFIED FRONTAL SYSTEM RESPONSIBLE FOR INCURSION OF COLD CANADIAN
AIR ONTO THE PLAINS CROSSES THE RGN LT TONIGHT...WITH BUFR
SOUNDINGS STILL POINTING TWDS BRIEF PERIOD OF BREEZY CONDITIONS
POST FROPA AFTER 02-04Z TONIGHT. TEMPS WL LKLY BE STABLE ERY
ON...TANKING LATE BEHIND THE FRONT. MINIMA IN THE 20S INLAND TO NR
30 SE COAST.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
UPR TROF FLATTENS A LITTLE BIT TOMORROW...AND MID LVL FLOW BECOMES
ZONAL BY WED MRNG...THUS ALLOWING SFC HIGH PRESSURE TO BRIEFLY
BUILD INTO THE AREA. DRY WX THROUGHOUT THE PERIOD WITH HIGHS IN
THE LWR/MID 30S NE TO LWR 40S SOUTH. NEXT TROF DIGS INTO THE
MIDWEST LTR WED/THU...RAPIDLY SHUNTING ANOTHER AREA OF PIECE OF
S/W ENERGY ACROSS THE GRT LAKES TOWARDS THE NORTHERN MID-ATLC ON
THU. MAIN FORCING REMAINS WELL NORTH OF THE CWA...AND AS PRVS
SHIFT NOTED...MAY WELL SEE A STRAY SNOW SHOWER OR TWO OVER EASTERN
SHORE (AND MAYBE A BAY EFFECT FLURRY OR TWO OVER THE TIDEWATER?).
HOWEVER...WL KEEP POPS AT SILENT OR LESS FOR NOW. MAIN HEADLINE WL
BE THE COLD. SREFS NOW HINTING AT DOWNRIGHT WINDY CONDS FOR MOST
OF THE AREA THU...WITH TEMPS INTO THE UPR 30S NW TO LWR/MID 40S
SE EXPECTED. WIND CHILLS WL BE IN THE SINGLE DIGITS OVER NORTHERN
HALF OF THE AREA THU NGT...APPROACHING ZERO ACROSS THE EASTERN
SHORE. LOW TEMPS ERY FRIDAY MORNING WILL BE IN THE LWR TEENS NW/N
TO LWR 20S SE. WL CONTINUE TO OUTLOOK COLD AND WIND CHILLS IN HWO.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
CLIPPER LOW DEPARTS TOWARDS ATLANTIC CANADA THU NIGHT AS COLD
HIGH PRES BUILDS IN FROM THE W. THIS WL ALLOW FOR COLD ARCTIC AIR
(THE COLDEST OF THE SEASON) TO ENVELOP THE ERN SEABOARD. AS WITH
THE UPR TROF PUSHING INTO THE REGION TODAY...EURO/GFS NOW TRENDING
TOWARDS FLATTENING OUT UPR RIDGE...WHICH WOULD ALLOW FOR MID/UPR
FLOW TO BE A BIT MORE WLY VICE NWLY. HV THEREFORE MADE VERY MINOR
ADJUSTMENTS TO T/TD GRIDS ON FRIDAY...NUDGING MAXIMA UPWARD FRIDAY
BY A DEGREE OR TWO. MAKE NO MISTAKE THROUGH...TIGHT SFC NWLY FLOW
AND COLD TEMPS WL MAKE FOR A CHILLY DAY. LOOK FOR WIND CHILLS IN
THE TEENS AND 20S FOR MUCH OF THE DAY FRIDAY TO MAKE ANY OUTDOOR
ACTIVITIES...LESS THAN PLEASANT.
AIR TEMPS ON FRI WILL STRUGGLE TO GET ABOVE FREEZING EVEN UNDER A
MOSTLY SUNNY SKY...WITH ONLY MID/UPPER 20S NW/N TO L30S SE
EXPECTED. COLDEST NIGHT OF THE YEAR THUS FAR FOR MOST SITES WL
LIKELY BE FRI NIGHT...UPR SINGLE DIGITS NW/N TO NEAR 20 FAR SE.
TEMPS START TO MODERATE ON SAT WITH THE FLOW BECOMING SW AS THE
HIGH SLIDES OVERHEAD OF THE AREA. HIGHS SAT WILL `WARM` INTO THE
LWR TO MID 30S...WITH LOWS SAT NIGHT INTO THE UPR TEENS TO UPR
20S.
HIGH PRES MOVES OFFSHORE AND AWAY FROM THE COAST ON SUN...AS A COLD
FRONT AND AREA OF LOW PRES APPROACHES FROM THE W. PREV MODEL RUNS
HAVE KEPT OUR AREA DRY AS THIS FRONT/LOW MOVE ACROSS THE
MID-ATLANTIC...ALTHO LATEST GFS/ECMWF NOW DEPICT A MORE SRN TRACK
TAPPING ADDITIONAL MOISTURE. WILL KEEP THE EXTENDED FCST DRY FOR NOW
UNTIL MODELS/TRENDS BECOME MORE CONSISTENT WITH THIS FEATURE. HIGHS
CONTINUE THEIR UPWARD TREND ON SUN AND MON TO NEAR 40 FAR NW/N TO
NEAR 50 SE...WITH LOWS IN THE LWR 20S TO LWR 30S.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
A LOW PRESSURE SYSTEM WAS CENTERED ABOUT 40 MILES S OF CAPE
LOOKOUT NC AT 17Z. LIGHT RAIN HAS BROKEN OUT ACROSS ERN NC AND FAR
SE VA. CEILINGS HAVE LOWERED AT THE TAF SITES WITH IFR AT ECG AND MVFR
PRESENT OR SOON TO DEVELOP AT THE OTHER TAF SITES. AS THE LOW
MOVES OFF TO THE NE...RAIN WILL END AROUND 00Z. VFR CONDITIONS
WILL DEVELOP TONIGHT AND CONTINUE WED AS HIGH PRESSURE BUILDS
INTO THE AREA.
VFR CONDITIONS WILL PREVAIL DURING THE NEXT SEVERAL DAYS. WINDS
WILL BE GUSTY AT TIMES THU AS AN ARCTIC COLD FRONT CROSSES THE
AREA. A LOW PRESSURE SYSTEM MAY IMPACT THE AREA SUN WITH A CHANCE
OF PRECIPITATION AND POSSIBLY LOWERING AVIATION CONDITIONS.
&&
.MARINE...
SFC HI PRES SLO TO RLS GRIP THIS MRNG. LO PRES TRACKS NE FM CSTL NC
TO A FEW HUNDREDS MI E OF VA CAPES BY LT THIS EVE. WNDS/SEAS RMNG
BLO SCA THROUGH THIS EVE. LO PRES CONTS TO MV AWAY FM CST LT
TNGT...AFT CDFNTL PASSAGE...MOD LLVL CAA DVLPS AND CONTS THROUGH WED
MRNG. HOISTING GALES FOR NRN 3 OCN ZNS FOR GUSTS TO 35 KT...OTRW
STRNG SCAS WL BE ADVERTISED. WKNG CAA WED AFTN LEADS TO DCRS TRENDS
FOR WNDSPDS/SEAS INTO WED NGT. NEXT CLIPPER/CDFNT POISED TO CRS THE
WTRS THU AFTN...LEADING TO NEXT PD OF STRNG SCAS/PSBL LO END GALES
INTO FRI (AS COLDEST AMS OF WINTER THUS FAR ARRIVES).
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 11 AM EST
WEDNESDAY FOR ANZ630>633-656-658.
GALE WARNING FROM 1 AM TO 9 AM EST WEDNESDAY FOR ANZ650-652-
654.
&&
$$
SYNOPSIS...MAM
NEAR TERM...MAM
SHORT TERM...MAM
LONG TERM...JRL/MAM
AVIATION...LSA
MARINE...ALB
000
FXUS61 KRNK 131731
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
1231 PM EST TUE JAN 13 2009
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE REGION THIS AFTERNOON FOLLOWED
BY COLD HIGH PRESSURE FOR MIDWEEK. AN ARCTIC COLD FRONT WILL CROSS
THE AREA LATE WEDNESDAY NIGHT AND THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
FRONT LOCATED OVER CENTRAL KY WITH NARROW BAND OF SNOW SHOWERS
EXTENDING FROM EAST OF LEX-EAST OF BNA. THE 12KM NAM/12Z RUC ARE
PICKING THIS UP PRETTY GOOD. NOT IMPRESSED WITH THE AMOUNTS AS IT
MOVES INTO THE WESTERN TERRAIN THIS AFTERNOON. STILL LOOKS LIKE BEST
CHANCE OF SNOW IN MOUNTAINS WILL BE FROM 19Z THROUGH EARLY
EVENING. THERE IS LITTLE TO NO INFLOW FROM THE LAKES. FOR NOW
SEEING AN INCH OR LESS BY THE END OF THE DAY OVER WRN GREENBRIER
SOUTH TO FLAT TOP WV AND RICHLANDS VA. AIRMASS IS COLDER...SO
THINK MOST PRECIP WILL BE IN THE FORM OF SNOW.
THICK CS EXTENDS FROM THE NEW RIVER VALLEY EAST...AND MODELS START
PUSHING THIS EAST BY LATE AFTERNOON. WITH THICK BKN-OVC SKIES OUT
EAST...HAVE LOWER HIGHS A FEW DEGREES. SOME BREAKS THIS AFTERNOON
SHOULD KEEP CURRENT FOREAST HIGHS IN THE UPPER 30S TO UPPER 40S
FROM THE NEW RIVER VALLEY SOUTH INTO THE NC MTNS/FOOTHILLS.
WINDS PICK UP TONIGHT BEHIND THE FRONT BUT ARE EXPECTED TO REMAIN
BELOW ADVISORY CRITERIA. WILL STAY CLOSE TO TEMPERATURE GUIDANCE
FOR HIGHS TODAY AND LOWS TONIGHT.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
ON WEDNESDAY...THE HIGH PRESSURE MAKES A BRIEF VISIT TO THE
REGION...PROVIDING FOR PLENTY OF SUNSHINE...EVEN IN THE
MOUNTAINS...AND LIGHT WINDS. THE AIR BEHIND TODAYS COLD FRONT WILL
BE COLDER...BUT NOT SIGNIFICANTLY. HIGHS ON WEDNESDAY STILL SHOULD BE
IN THE MID-UPPER 30S IN THE MOUNTAINS AND LOW 40S EAST OF THE BLUE
RIDGE.
THE ONSET OF THE MUCH COLDER AIR WILL BEGIN WEDNESDAY NIGHT AS A
MUCH STRONGER COLD FRONT MOVES THROUGH THE REGION. UPSLOPE SNOW
SHOWERS IN THE MOUNTAINS WILL BE ON THE INCREASE THROUGH THE NIGHT.
GOOD PRESSURE RISES ALONG WITH GOOD COLD AIR ADVECTION BEHIND THE
FRONT WILL ALLOW FOR GUSTY WINDS IN THE MOUNTAINS. THE NORTHERN
MOUNTAINS OF NORTH CAROLINA AND THE NEIGHBORING MOUNTAIN EMPIRE
REGION OF SOUTHWEST VIRGINIA MAY SEE GUSTS AROUND 40 MPH BY DAYBREAK
THURSDAY.
ON THURSDAY UPSLOPE SNOW SHOWERS WILL CONTINUE...BUT COVERAGE WILL
GRADUALLY BE ON THE DECREASE. HIGH TEMPERATURES IN THE MOUNTAINS
WILL BE ONLY A FEW DEGREES HIGHER THAN MORNING LOWS. EAST OF THE
BLUE RIDGE..WE MAY SEE HIGHS 5 TO 8 DEGREES HIGHER THAN MORNINGS
LOWS. THE PRESSURE GRADIENT WILL WEAKEN A LITTLE THROUGH THE DAY AS
WELL...SO WIND SPEEDS ALSO WILL DECREASE SLOWLY THROUGH THE DAY.
THURSDAY NIGHT TEMPERATURES WILL CONTINUE TO FALL WITH READINGS BY
DAYBREAK THURSDAY IN THE SINGLE DIGITS IN THE MOUNTAINS...WITH
VALUES JUST A LITTLE ABOVE 10 EAST OF THE BLUE RIDGE. WINDS STILL
SHOULD BE IN THE 10 TO 15 MPH RANGE IN THE MOUNTAINS. THE
COMBINATION OF THE COLD TEMPERATURES AND THESE WINDS WILL ALLOW THE
WIND CHILL READING TO FALL BELOW WIND CHILL ADVISORY CRITERIA. WILL
CONTINUE TO HIGHLIGHT THIS CONCERN IN THE HAZARDOUS WEATHER OUTLOOK.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
ARCTIC DOME OF HIGH PRESSURE (1040+ MB) WILL PASS OVERHEAD FRIDAY
BRINGING VERY COLD AND DRY AIRMASS ACROSS THE FORECAST AREA...85H
TEMPS M18 TO M24 DEG C. SURFACE TEMPS FRIDAY WILL BE HARD PRESSED
TO GET OUT OF THE TEENS MOUNTAINS...20S EAST OF THE BLUE RIDGE.
THIS WILL SET STAGE FOR SINGLE DIGIT LOWS FRIDAY NIGHT. AREAS WITH
ANY SNOW COVER WILL LIKELY SEE SUBZERO SINGLE DIGIT LOWS...EVERYONE
ELSE SHOULD STAY ON THE PLUS SIDE OF ZERO.
TEMPS SHOULD GRADUALLY MODERATE SATURDAY INTO SUNDAY AHEAD OF
ANOTHER CONTINENTAL FRONT THAT WILL CROSS THE FORECAST AREA. WILL
SEE CHANCE OF SNOW WITH ITS PASSAGE LATE SUNDAY...FOLLOWED BY DRYING
AGAIN MONDAY.
&&
.AVIATION /18Z TUESDAY THROUGH SUNDAY/...
PRE-FRONTAL TROUGH NOW MOVING INTO THE BLUE RIDGE AHEAD OF FRONT
OVER ERN KY AT 17Z. THE WINDS BEHIND TROF ARE SWITCHING FROM
SOUTHWES TO WEST. THE COLD FRONT WILL MOVE EAST THROUGH BLF/LWB BY
22Z...MAKING IT TO ROANOKE BY 00Z AND LYH/DAN BY 02Z. WINDS ARE
GOING TO GUST UP TO 25-30 KNOTS THIS EVENING FOR A 6 HOUR OR LESS
PERIOD...MAINLY LEE OF THE HIGHLANDS AND ALONG/JUST EAST OF THE
BLUE RIDGE.
FOR BLF/LWB...CIGS WILL DROP TO MVFR WITH FRONTAL PASSAGE WITH
VSBYS DROPPING TO 3-5SM IN LIGHT SNOW SHOWERS. VSBYS WEST OF LWB
AND NORTH OF BLF MAY DROP TO IFR IN HEAVIER SNOW SHOWERS BETWEEN
22Z-03Z THIS EVENING.
CIGS WILL REMAIN MVFR AT BLF/LWB THROUGH DAYBREAK B4 DRIER AIR
SCATTERS OUT THE LOW LVLS. ELSEWHERE...LOOK FOR VFR CIGS OVERNIGHT
THEN CLEARING.
A STRONGER ARCTIC COLD FRONT WILL CROSS THE AREA WEDNESDAY NIGHT
ENHANCING THE THREAT FOR WESTERN MVFR CIGS/VSBYS IN MOUNTAIN SNOW
SHOWERS AND STRONG WINDS AT HIGHER ELEVATIONS THROUGH THURSDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/WP
SHORT TERM...DS
LONG TERM...PM
AVIATION...AMS/WP
000
FXUS61 KLWX 131540
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1040 AM EST TUE JAN 13 2009
.SYNOPSIS...
HIGH PRESSURE WILL MOVE OFF THE MID-ATLANTIC COAST TODAY. A COLD
FRONT WILL MOVE THROUGH THE REGION THIS EVENING. HIGH PRESSURE
WILL BUILD OVER THE REGION WEDNESDAY BRINGING DRY AND COLD
CONDITIONS. AN ALBERTA CLIPPER AND ITS ASSOCIATED COLD FRONT WILL
PASS THROUGH THURSDAY MORNING WITH VERY COLD CONDITIONS FOR THE
END OF THE WEEK.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
MID ATLANTIC IS BETWEEN TWO SYSTEMS EARLY THIS MORNING. ONE IS LOW
PRESSURE OFF THE CAROLINA COAST AND ANOTHER ONE IS LOW PRESSURE
OVER THE MIDWEST AND ITS ATTACHED FRONT THAT EXTENDS THROUGH THE
OHIO VALLEY. FIRST SYSTEM WILL REMAIN TO OUR SOUTHEAST...WITH JUST
A SLIGHT CHANCE OF RAIN SPREADING INTO OUR LOWER BAY ZONES AND
LOWER SOUTHERN MARYLAND. MORE IMPORTANTLY...A DECK OF MID TO HIGH
CLOUDS MORE OVER THE CWA THIS AFTERNOON ON THE NORTHERN FRINGE OF
LOW PRESSURE AND WITH AN UPPER JET OVERHEAD. THEREFORE...WILL
INCREASE SKY COVER TO MOSTLY CLOUDY ACROSS MOST AREAS.
IN ADDITION...THE FRONT OVER THE OHIO VALLEY WILL MOVE EAST ACROSS
THE HIGHLANDS LATE THIS AFTERNOON. AS THE FRONT MOVES THROUGH AND
WINDS TURN TO THE WEST NORTHWEST...SNOW SHOWERS WILL INCREASE IN
COVERAGE LATER TODAY. WILL BEGIN A WINTER WEATHER ADVISORY AT 4 PM
FOR THE UPSLOPE VULNERABLE COUNTIES ACROSS THE HIGHLANDS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM WEDNESDAY/...
COLD FRONT MOVES ACROSS THE REST OF THE CWA THIS EVENING. UPSLOPE
SNOW SHOWERS CONTINUE ACROSS THE HIGHLANDS FOR 1 TO 2 INCHES OF
ACCUMULATION. ADVISORY WILL EXPIRE AT 4 AM.
WILL HAVE TO WATCH THIS FRONT FOR A BAND OF PRECIPITATION ALONG
IT...BUT DO NOT THINK IT WILL BE ABLE TO MAKE IT EAST OF THE MTNS.
WILL HAVE LOW POPS FOR SNOW SHOWERS ACROSS PLACES LIKE
HAGERSTOWN...MARTINSBURG...AND WINCHESTER BUT WILL END IT THERE.
ALONG AND BEHIND THE FRONT...WINDS WILL KICK UP...GUSTING 30 TO 35
MPH. WIND CHILLS ACROSS THE HIGHLANDS MAY BE NEAR ZERO.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
BY EARLY WED...A SECOND AND MOST POTENT SHOT OF ARCTIC AIR WILL BE
BARRELING ITS WAY DOWN THE NRN PLAINS TOWARD THE EAST COAST. MODELS
HAVE DROPPED THE SFC LOW FURTHER SOUTH THAN SOLUTIONS 24 HRS AGO.
THE SFC LOW IS NOW EXPECTED TO TRACK JUST NORTH OF THE MASON DIXON
LINE...AFTER SLIDING EAST ACROSS THE I-70 CORRIDOR OF THE UPPER
MIDWEST. THE LOW ITSELF WILL BE FAIRLY WEAK AND ONLY A LIMITED
AMOUNT OF MOISTURE WRAPPED AROUND THE BACKSIDE...THOUGH THE
FORWARD PROGRESSION WILL BE FAIRLY QUICK. DURING THE LATE NIGHT
HRS WED...UPSLOPE SNOW WILL BEGIN IN THE CNTRL APLCNS AND LINGER
INTO THE MIDDAY THURS. A VERY LIMITED AMOUNT OF INSTABILITY MAY BE
IN PLACE ONCE THE VERY COLD LOW LEVEL REGIME FIRST REACHES MID
ATLC AHEAD OF THE LOW...DEVELOPING A FEW ISOLATED SNOW BANDS OR
CONVECTIVE-TYPE SNOW SHOWERS STREAMING ACROSS EXTREME NRN MD. A
FEW MAY SLIDE ACROSS THE REGION NORTH OF I-66...SO THE LOW CHANCE
POPS REMAIN FOR THE OVERNIGHT HRS AS THE LOW FIRST BEGINS TO
AFFECT THE MID ATLC...SLIDING ACROSS SRN PA.
WINDS WILL PICK UP QUICKLY ACROSS THE REGION DURING THE MID MRNG
HRS THURSDAY. GUSTS RANGING 25-35 MPH WILL SPREAD QUICKLY ACROSS NRN
MD/NOVA INTO THE LATE AFTN HRS. TEMPS WILL BARELY RISE INTO THE
M/U20S AREAWIDE...NEAR FREEZING ACROSS THE SRN REACHES OF THE CWA.
A LOW CHANCE OF SCATTERED SNOW BANDS WILL REMAIN ACROSS THE PA
BORDER THRU THE AFTN HRS...THO THE LOW LEVELS ARE EXPECTED TO BE
TOO DRY IN THE AFTN FOR LITTLE MORE THAN FLURRIES MAKING IT TO THE
SFC.
RELENTLESS COLD AIR WILL THEN TANK TEMPS INTO THE SINGLE DIGITS
QUICKLY THRU THE EVNG HRS THURSDAY...BARELY INTO THE TEENS ACROSS
THE I-95 CORRIDOR. OVERNIGHT...DANGEROUS WIND CHILLS ARE EXPECTED
ACROSS THE REGION...W/ POSSIBLE WIND CHILL WARNINGS FOR THE WRN
ZONES OF THE CNTRL APLCN REGION AND ADVISORIES ACROSS MUCH OF THE
SHENANDOAH VALLEY INTO PORTIONS OF THE MID ATLC PIEDMONT. WINDS
OVERNIGHT WILL BE GRADUALLY DECREASING FROM THE NW...FROM THE
15-20 MPH RANGE DURING THE LATE EVNG TO 5-10 MPH RANGE DURING THE
PRE-DAWN HRS...BUT W/ AMBIENT TEMPS IN THE SINGLE DIGITS AND JUST
ABOVE...WIND CHILL VALUES WILL CERTAINLY BE ENOUGH TO WARRANT A
LEAST ADVISORY CRITERIA.
HIGHS ON FRIDAY WON/T REBOUND MUCH...ONLY CLIPPING THE UPPER TEENS
ACROSS THE WEST AND NEAR 20 CLOSER TO THE COAST. BREEZY WLY WINDS
DURING THE AFTN WILL MAKE IT FEEL LIKE THE SINGLE DIGITS THOUGH. A
SECOND NIGHT OF TEMPS JUST ABOVE ZERO ACROSS THE WEST AND EVEN
COLDER ACROSS THE I-95 CORRIDOR...FORTUNATELY WINDS WILL BE LIGHT
AS THE CENTER OF A 1040MB SFC HIGH CROSSES OVER THE APLCNS AND ERN
SEABOARD. THE WEEKEND STILL UNCERTAIN...AS THE INITIALLY TYPICAL
QUICK MOVING VORT LOBE OVER THE GREAT LAKES HAS NOW BEEN MODIFIED BY
LR MODELS TO STALL ACROSS THE ERN GREAT LAKES...AND PULL UP A BIT
MORE GULF MOISTURE UP THE ATLC COAST. SEVERAL WEAKER TROF AXIS
REGIONS LOOKS TO SLIDE DOWN THE BACKSIDE OF THE UPPER LONGWAVE OVER
THE WEEKEND...MAKING FOR A SLOWER EXIT TO THE COLD REGIME...LASTING
INTO EARLY NEXT WEEK /THO NOT QUITE AS COLD AS THU/FRI OF THIS WEEK/.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
VFR CONDS TDA AND TNGT. WINDS WL GUST TNGT INTO 20+ KT RANGE AFTER
CD FNT MOVES THRU THE MID ATLC RGN.
WINDS THE MAIN CONCERN THROUGH THE REMAINDER OF THE WEEK. WED
AFTN...WINDS WILL BE GRADUALLY SUBSIDING AND REMAINING FAIRLY
LIGHT THRU THE EARLY MRNG HRS THURSDAY. A COLD FRONT WILL SLIDE
ACROSS THE REGION DURING THE MID MRNG HRS THURSDAY...W/ W-NWLY
WINDS QUICKLY PICKING UP BEHIND THE BOUNDARY. SFC WINDS EXPECTED
TO GUST 20-30KT...W/ A 40-50KT LL JET SLIDING ACROSS THE REGION
DURING THE AFTN. WEAKER GUSTS ON FRI AFTN...THEN LITTLE CONCERN
THRU EARLY NEXT WEEK OTHER THAN VERY COLD TEMPS.
&&
.MARINE...
COLD FRONT MOVES THROUGH THIS EVENING. ALONG AND BEHIND THE
FRONT...WIND GUSTS WILL REACH SMALL CRAFT ADVISORY CRITERIA
POSSIBLY EVEN TEASING 35 KT /GALE CRITERIA/ FOR A BRIEF PERIOD OF
TIME.
A COLD FRONT WILL MOVE OFF THE ATLC COAST EARLY WED...W/ ANOTHER
LOW PRESSURE SYSTEM SLIDING INTO THE REGION OVERNIGHT WED INTO THE
EARLY MRNG HRS THURS. GUSTY WINDS WILL BRIEFLY PEAK NEAR GALE OVER
SRN/CNTRL PORTIONS OF THE BAY MIDDAY THURS...BUT MAINLY SOLID SCA
CONDITIONS OVER THE WATERS ALL-DAY THURSDAY. LESSER CONCERNS FOR
FRIDAY AFTN...AND FAIRLY LIGHT WINDS OVER THE WATER FOR THE COMING
WEEKEND.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 4 AM EST
WEDNESDAY FOR MDZ501.
VA...WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 4 AM EST
WEDNESDAY FOR VAZ021.
WV...WINTER WEATHER ADVISORY FROM 4 PM THIS AFTERNOON TO 4 AM EST
WEDNESDAY FOR WVZ054-501-503.
MARINE...SMALL CRAFT ADVISORY FROM 9 PM THIS EVENING TO 1 PM EST
WEDNESDAY FOR ANZ530>537.
&&
$$
SYNOPSIS...PELOQUIN
NEAR TERM...PELOQUIN
SHORT TERM...PELOQUIN
LONG TERM...GMS
AVIATION...WOODY!/GMS
MARINE...PELOQUIN/GMS
000
FXUS61 KRNK 131510
AFDRNK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
1010 AM EST TUE JAN 13 2009
.SYNOPSIS...
A COLD FRONT WILL MOVE THROUGH THE REGION THIS AFTERNOON FOLLOWED
BY COLD HIGH PRESSURE FOR MIDWEEK. AN ARCTIC COLD FRONT WILL CROSS
THE AREA LATE WEDNESDAY NIGHT AND THURSDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
FRONT LOCATED OVER CENTRAL KY WITH NARROW BAND OF SNOW SHOWERS
EXTENDING FROM EAST OF LEX-EAST OF BNA. THE 12KM NAM/12Z RUC ARE
PICKING THIS UP PRETTY GOOD. NOT IMPRESSED WITH THE AMOUNTS AS IT
MOVES INTO THE WESTERN TERRAIN THIS AFTERNOON. STILL LOOKS LIKE BEST
CHANCE OF SNOW IN MOUNTAINS WILL BE FROM 19Z THROUGH EARLY
EVENING. THERE IS LITTLE TO NO INFLOW FROM THE LAKES. FOR NOW
SEEING AN INCH OR LESS BY THE END OF THE DAY OVER WRN GREENBRIER
SOUTH TO FLAT TOP WV AND RICHLANDS VA. AIRMASS IS COLDER...SO
THINK MOST PRECIP WILL BE IN THE FORM OF SNOW.
THICK CS EXTENDS FROM THE NEW RIVER VALLEY EAST...AND MODELS START
PUSHING THIS EAST BY LATE AFTERNOON. WITH THICK BKN-OVC SKIES OUT
EAST...HAVE LOWER HIGHS A FEW DEGREES. SOME BREAKS THIS AFTERNOON
SHOULD KEEP CURRENT FOREAST HIGHS IN THE UPPER 30S TO UPPER 40S
FROM THE NEW RIVER VALLEY SOUTH INTO THE NC MTNS/FOOTHILLS.
WINDS PICK UP TONIGHT BEHIND THE FRONT BUT ARE EXPECTED TO REMAIN
BELOW ADVISORY CRITERIA. WILL STAY CLOSE TO TEMPERATURE GUIDANCE
FOR HIGHS TODAY AND LOWS TONIGHT.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
ON WEDNESDAY...THE HIGH PRESSURE MAKES A BRIEF VISIT TO THE
REGION...PROVIDING FOR PLENTY OF SUNSHINE...EVEN IN THE
MOUNTAINS...AND LIGHT WINDS. THE AIR BEHIND TODAYS COLD FRONT WILL
BE COLDER...BUT NOT SIGNIFICANTLY. HIGHS ON WEDNESDAY STILL SHOULD BE
IN THE MID-UPPER 30S IN THE MOUNTAINS AND LOW 40S EAST OF THE BLUE
RIDGE.
THE ONSET OF THE MUCH COLDER AIR WILL BEGIN WEDNESDAY NIGHT AS A
MUCH STRONGER COLD FRONT MOVES THROUGH THE REGION. UPSLOPE SNOW
SHOWERS IN THE MOUNTAINS WILL BE ON THE INCREASE THROUGH THE NIGHT.
GOOD PRESSURE RISES ALONG WITH GOOD COLD AIR ADVECTION BEHIND THE
FRONT WILL ALLOW FOR GUSTY WINDS IN THE MOUNTAINS. THE NORTHERN
MOUNTAINS OF NORTH CAROLINA AND THE NEIGHBORING MOUNTAIN EMPIRE
REGION OF SOUTHWEST VIRGINIA MAY SEE GUSTS AROUND 40 MPH BY DAYBREAK
THURSDAY.
ON THURSDAY UPSLOPE SNOW SHOWERS WILL CONTINUE...BUT COVERAGE WILL
GRADUALLY BE ON THE DECREASE. HIGH TEMPERATURES IN THE MOUNTAINS
WILL BE ONLY A FEW DEGREES HIGHER THAN MORNING LOWS. EAST OF THE
BLUE RIDGE..WE MAY SEE HIGHS 5 TO 8 DEGREES HIGHER THAN MORNINGS
LOWS. THE PRESSURE GRADIENT WILL WEAKEN A LITTLE THROUGH THE DAY AS
WELL...SO WIND SPEEDS ALSO WILL DECREASE SLOWLY THROUGH THE DAY.
THURSDAY NIGHT TEMPERATURES WILL CONTINUE TO FALL WITH READINGS BY
DAYBREAK THURSDAY IN THE SINGLE DIGITS IN THE MOUNTAINS...WITH
VALUES JUST A LITTLE ABOVE 10 EAST OF THE BLUE RIDGE. WINDS STILL
SHOULD BE IN THE 10 TO 15 MPH RANGE IN THE MOUNTAINS. THE
COMBINATION OF THE COLD TEMPERATURES AND THESE WINDS WILL ALLOW THE
WIND CHILL READING TO FALL BELOW WIND CHILL ADVISORY CRITERIA. WILL
CONTINUE TO HIGHLIGHT THIS CONCERN IN THE HAZARDOUS WEATHER OUTLOOK.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
ARCTIC DOME OF HIGH PRESSURE (1040+ MB) WILL PASS OVERHEAD FRIDAY
BRINGING VERY COLD AND DRY AIRMASS ACROSS THE FORECAST AREA...85H
TEMPS M18 TO M24 DEG C. SURFACE TEMPS FRIDAY WILL BE HARD PRESSED
TO GET OUT OF THE TEENS MOUNTAINS...20S EAST OF THE BLUE RIDGE.
THIS WILL SET STAGE FOR SINGLE DIGIT LOWS FRIDAY NIGHT. AREAS WITH
ANY SNOW COVER WILL LIKELY SEE SUBZERO SINGLE DIGIT LOWS...EVERYONE
ELSE SHOULD STAY ON THE PLUS SIDE OF ZERO.
TEMPS SHOULD GRADUALLY MODERATE SATURDAY INTO SUNDAY AHEAD OF
ANOTHER CONTINENTAL FRONT THAT WILL CROSS THE FORECAST AREA. WILL
SEE CHANCE OF SNOW WITH ITS PASSAGE LATE SUNDAY...FOLLOWED BY DRYING
AGAIN MONDAY.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
THROUGH 18Z TUESDAY...EXPECT VFR CONDITIONS. THE WINDS WILL
GRADUALLY BECOME SOUTHWEST AROUND 5 TO 10 KTS IN ADVANCE OF AN
APPROACHING COLD FRONT.
THIS COLD FRONT IS EXPECTED TO MOVE THROUGH THE REGION BETWEEN
21Z AT KBLF AND KLWB...00Z AT KROA AND 03Z AT KLYH AND KDAN. IN
THE MOUNTAINS...BEHIND THE FRONT LOOK FOR CIGS TO DROP TO MVFR
LEVELS WITH MVFR VSBYS DUE TO RAIN AND SNOW SHOWERS. THIS TIMING
CLOSELY FOLLOW THE LATEST LOCAL WRF MODEL.
EAST OF THE BLUE RIDGE...NO OBSTRUCTION TO VISIBILITY ARE
EXPECTED AND CIGS SHOULD REMAIN VFR. WINDS WILL INCREASE FROM THE
NORTHWEST AND GUST TO AROUND 20-30KTS.
A STRONGER ARCTIC COLD FRONT WILL CROSS THE AREA WEDNESDAY NIGHT
ENHANCING THE THREAT FOR WESTERN MVFR CIGS/VSBYS IN MOUNTAIN SNOW
SHOWERS AND STRONG WINDS AT HIGHER ELEVATIONS THROUGH THURSDAY.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.
&&
$$
SYNOPSIS...AMS
NEAR TERM...AMS/WP
SHORT TERM...DS
LONG TERM...PM
AVIATION...AMS/DS
| 
