000
FXUS61 KPHI 201619
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1115 AM EST TUE JAN 20 2009
.SYNOPSIS...
AN AREA OF LOW PRESSURE NEAR THE COAST OF THE CAROLINAS WILL TRACK
NORTHEASTWARD TODAY AND TONIGHT, SLIDING WELL TO OUR EAST. MEANWHILE,
HIGH PRESSURE IS FORECAST TO EXPAND INTO OUR AREA FROM THE
TENNESSEE AND OHIO VALLEYS DURING WEDNESDAY. AN AREA OF LOW
PRESSURE SHOULD THEN TRACK TO OUR NORTH ON FRIDAY, SWEEPING A COLD
FRONT ACROSS OUR AREA FRIDAY NIGHT. HIGH PRESSURE IS ANTICIPATED
TO GRADUALLY BUILD IN OVER THE WEEKEND. THIS HIGH WILL SLIDE TO
OUR EAST AND NORTHEAST ON EARLY MONDAY, AS A STORM SYSTEM DEVELOPS
ACROSS THE SOUTHERN PLAINS.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
AT 1100 AM, IT WAS MOSTLY SUNNY OVER OUR FORECAST AREA, WITH JUST
SOME CIRRUS OVERHEAD. TEMPERATURES WERE MAINLY IN THE 20S AND A
NORTH TO NORTHWEST WIND WAS BEGINNING TO INCREASE IN SPEED.
THE NORTHWESTERN EDGE OF THE CLOUDS ASSOCIATED WITH THE LOW OFF THE
NORTH CAROLINA COAST WAS UP OVER SOUTHEASTERN MARYLAND LATE THIS
MORNING. THE CLOUDS MAY EXPAND A LITTLE FARTHER NORTHWESTWARD THIS
AFTERNOON AND THERE COULD BE SOME SPOTTY LIGHT PRECIPITATION IN OUR
SOUTHEASTERN COUNTIES LATE IN THE DAY.
THE PREVIOUS FORECAST REMAINS ON TRACK.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
THE DEEP UPPER-LEVEL TROUGH WILL REMAIN ACROSS THE EASTERN UNITED
STATES FOR A TIME, HOWEVER A PATTERN CHANGE IS ANTICIPATED AS WE GO
THROUGH WEDNESDAY NIGHT AND THURSDAY. THE TROUGH WILL BE LIFTING OUT
AS ENERGY IN CANADA DIVES FARTHER TO THE WEST. THE COMPUTER MODELS
ALONG WITH THE ENSEMBLES AGREE RATHER WELL ON THE OVERALL LARGER
SCALE PATTERN. AS THE COASTAL LOW SLIDES TO OUR EAST TONIGHT, OUR
FAR SOUTHERN AND EASTERN COUNTIES MAY BE BRUSHED BY A TOUCH OF
LIGHT SNOW. AS A RESULT, WE CARRIED SLIGHT CHC TO LOW CHC POPS
FOR THE FIRST HALF OF THE NIGHT. ELSEWHERE, NO MEASURABLE
PRECIPITATION IS EXPECTED DESPITE SOME SHORT WAVE ENERGY SLIDING
BY. ALTHOUGH, SOME FLURRIES IN THE POCONOS ARE POSSIBLE GIVEN THE
COLD NORTHWESTERLY FLOW, WHICH MAY ALLOW SOME LAKE EFFECT MOISTURE
TO REACH THERE. THE PRESSURE GRADIENT HOLDS UP FOR AWHILE TONIGHT,
THEREFORE A GUSTY WIND SHOULD CONTINUE FOR A TIME, BEFORE
DIMINISHING SOME.
GRADUALLY HIGH PRESSURE BUILDS INTO OUR REGION FROM THE SOUTHWEST
WEDNESDAY NIGHT AND THURSDAY AS THE UPPER TROUGH BEGINS TO LIFT
NORTHEASTWARD. SOME WAA FROM THE MIDWEST TOWARD THE OHIO VALLEY WILL
BE AHEAD OF A FRONTAL BOUNDARY. THE BULK OF THE LIFT ASSOCIATED WITH
A SHORT WAVE IS EXPECTED TO SLIDE ACROSS EASTERN CANADA. THIS COULD
TOSS SOME MORE CLOUDS INTO OUR AREA THOUGH, ESPECIALLY OUR NORTHERN
ZONES WEDNESDAY INTO THURSDAY. THE WAA IS MORE NOTABLE ON THURSDAY
AS THE UPPER TROUGH FLATTENS OUT MORE, ALLOWING OUR WINDS TO BACK A
BIT. THIS WILL ALLOW TEMPERATURES TO REBOUND MORE IN THE AFTERNOON
TO NEAR WHERE WE SHOULD BE FOR THIS TIME OF THE YEAR. WE THEN TURN
OUR ATTENTION TO THE NORTHERN PLAINS AS A SHORT WAVE DIVING
SOUTHEASTWARD BEGINS TO AMPLIFY AN UPPER-LEVEL TROUGH. THIS WILL
DRIVE A COLD FRONT ACROSS THE NORTHERN TIER STATES AND INTO THE
GREAT LAKES AND TOWARD THE NORTHEAST ON FRIDAY.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
THE RETREATING OF THE LARGE UPPER-LEVEL TROUGH IN THE EAST WILL
ALLOW FOR A MODERATION IN THE TEMPERATURE DEPARTMENT TO START THIS
TIME FRAME OFF. THE UPPER-LEVEL FLOW PATTERN IS FAIRLY WELL AGREED
UPON AMONG THE OPERATIONAL MODEL GUIDANCE AS WELL AS THE ENSEMBLES.
THEY BASICALLY ARE GOING WITH A MORE ZONAL FLOW FOR A TIME, BEFORE
MORE TROUGHING BEGINS TO DIG INTO THE GREAT LAKES, NORTHEAST AND MID
ATLANTIC REGIONS. THE LEADING EDGE OF ANOTHER DEVELOPING UPPER-LEVEL
TROUGH WILL BE A SHORT WAVE DIVING SOUTHEASTWARD ACROSS THE MIDWEST
AND GREAT LAKES REGION ON FRIDAY. THE TIMING OF THIS FEATURE
GENERALLY LOOKS GOOD AMONG THE MODELS, ALTHOUGH THE DETAILS SUCH AS
THE THERMAL FIELDS DIFFER SOME. THIS SYSTEM IS PROBABLY MORE OF A
CLIPPER TYPE SYSTEM AS IT TRACKS THROUGH THE GREAT LAKES AND INTO
NEW ENGLAND, AND LOOKS TO BE RATHER MOISTURE STARVED.
AS THIS OCCURS, RISING HEIGHTS ALONG WITH A SOUTHERLY FLOW ACROSS
OUR REGION WILL COMBINE WITH WAA. AS THE SURFACE HIGH IS FORECAST TO
BE TO OUR EAST, WE ARE NOT EXPECTING ANY COLD AIR DAMMING TO OCCUR,
THEREFORE A DECENT MODERATION OF THE AIR MASS IS EXPECTED FOR FRIDAY.
AS THIS SYSTEM CRUISES TO OUR NORTH LATER FRIDAY, IT WILL SWEEP A
COLD FRONT ACROSS OUR REGION. AS THE UPPER-LEVEL TROUGH SHARPENS
WITH THE PASSAGE OF THE ASSOCIATED SHORT WAVE, MUCH COLDER AIR
WILL ONCE AGAIN GET PULLED DOWN INTO OUR AREA UNDER A STRENGTHENING
NORTHWESTERLY FLOW/CAA REGIME. WHILE THE CORE OF THIS COLD AIR
MASS IS EXPECTED TO REMAIN WELL UP TO OUR NORTH, THE COLDER
WEATHER IS FORECAST TO LINGER THROUGH THE WEEKEND AND EARLY NEXT
WEEK. WHAT THEN GETS OUR ATTENTION IS THE TRANSITION THAT TAKES
PLACE AS ENERGY BEGINS TO DIVE ACROSS THE WESTERN STATES AND IS
EJECTED ACROSS THE SOUTHERN STATES. THE MODEL GUIDANCE SUGGESTS
THAT GIVEN THE UPPER-LEVEL PATTERN, A TIGHTENING THERMAL GRADIENT
WILL BE IN PLACE TO OUR SOUTH. THERE ARE INDICATIONS THAT A LARGE
SURFACE HIGH THAT SLIDES ACROSS OUR AREA OVER THE WEEKEND, TURNS
TO THE NORTHEAST AND BECOMES ENTRENCHED OVER SOUTHEASTERN CANADA.
AS THIS OCCURS, MIDLEVEL SHORT WAVE ENERGY ALONG WITH SOME SURFACE
FEATURES INTERACT WITH THE STRENGTHENING BAROCLINIC ZONE TO OUR
SOUTH AND SOUTHWEST. THIS SCENARIO STRONGLY LEANS TOWARDS
OVERRUNNING PRECIPITATION FOR THE MID ATLANTIC REGION PERHAPS AS
EARLY AS LATE IN THE WEEKEND /SUNDAY NIGHT/, BUT ESPECIALLY
STARTING EARLY IN THE WEEK. THIS COULD BE IN THE FORM OF SNOW OR
EVEN A MIX, WHICH WILL ULTIMATELY DEPEND ON THE ATMOSPHERIC
THERMAL PROFILE.
THE ONLY SIGNIFICANT CHANGE WAS TO INCREASE THE HIGH TEMPERATURES
SEVERAL DEGREES ON FRIDAY DUE TO THE WAA AND RETURN FLOW AHEAD OF
THE NEXT COLD FRONT. OTHERWISE, WE BLENDED IN A SMALL PERCENTAGE OF
MOSGUIDE WITH CONTINUITY TO INTRODUCE SOME NEW DATA INTO THE
FORECAST. THIS WAS ESPECIALLY TRUE FOR TEMPERATURES, DEW POINTS AND
WINDS. TEMPERATURES ON SATURDAY MAY ACTUALLY TOP OUT EARLY IN THE
DAY, THEN GRADUALLY FALL. FOR THE MONDAY POTENTIAL, WE CARRIED
CHC POPS FOR SNOW FOR THE NORTHERN INTO THE CENTRAL AREAS, WITH A
GENERIC CHC OF RAIN/SNOW FURTHER SOUTH. THAT IS ALL FOR NOW.
THANKS TO THE SURROUNDING OFFICES FOR THE COLLABORATION EARLY THIS
MORNING. HAVE A GOOD ONE!
&&
.AVIATION /16Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
SFC OBS AND SATELLITE IMAGERY INDICATE JUST A THIN CIRRUS DECK OVER
OUR TAF SITES LATE THIS MORNING. WINDS ARE EXPECTED TO INCREASE THIS
AFTERNOON UNDER THE INFLUENCE OF A TIGHTENING GRADIENT BETWEEN A
DEVELOPING COASTAL LOW TO OUR SOUTH AND SOUTHEAST, AND A HIGH
PRESSURE RIDGE WELL TO OUR WEST AND NORTHWEST. NO PRECIPITATION IS
EXPECTED AT THE TAF SITES THROUGH THE NEXT 36 HOURS.
OUTLOOK...
A BRISK NORTHWEST FLOW WILL PREVAIL THROUGH MOST OF WEDNESDAY AS
AN INCREASED GRADIENT WILL EXIST BETWEEN THE OFFSHORE LOW AND HIGH
PRESSURE RIDGING TO OUR SOUTH. THE WINDS ARE EXPECTED TO DIMINISH
LATER WEDNESDAY AS A WEAK AREA OF HIGH PRESSURE TO THE SOUTH NOSES
NORTHWARD. THEN, VFR CONDITIONS ARE ANTICIPATED DURING THE MID TO
LATE PORTION OF THIS WEEK. THE NEXT WEATHER MAKER LOOKS TO BE IN
THE FORM OF A COLD FRONT ARRIVING LATER FRIDAY.
&&
.MARINE...
NORTHWEST WINDS WERE PICKING UP OVER THE COASTAL WATERS LATE THIS
MORNING AS THE PRESSURE GRADIENT INCREASES BETWEEN A DEVELOPING LOW
MOVING OFF THE NORTH CAROLINA COAST AND A HIGH PRESSURE SYSTEM WELL
TO OUR WEST. WILL KEEP THE SCA EXPIRATION TIME AT 15Z WEDNESDAY.
NO OTHER SIGNIFICANT WEATHER IS EXPECTED UNTIL A COLD FRONT, UNDER A
FAIRLY BROAD UPPER TROUGH, MOVES THROUGH LATE FRIDAY OR FRIDAY
EVENING.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST WEDNESDAY FOR
ANZ430-431-450>455.
&&
$$
SYNOPSIS...GORSE
NEAR TERM...IOVINO
SHORT TERM...GORSE
LONG TERM...GORSE
AVIATION...MIKETTA
MARINE...MIKETTA
000
FXUS61 KPHI 200910
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
410 AM EST TUE JAN 20 2009
.SYNOPSIS...
AN AREA OF LOW PRESSURE NEAR THE COAST OF THE CAROLINAS WILL TRACK
NORTHEASTWARD TODAY AND TONIGHT, SLIDING WELL TO OUR EAST. MEANWHILE,
HIGH PRESSURE IS FORECAST TO EXPAND INTO OUR AREA FROM THE
TENNESSEE AND OHIO VALLEYS DURING WEDNESDAY. AN AREA OF LOW
PRESSURE SHOULD THEN TRACK TO OUR NORTH ON FRIDAY, SWEEPING A COLD
FRONT ACROSS OUR AREA FRIDAY NIGHT. HIGH PRESSURE IS ANTICIPATED
TO GRADUALLY BUILD IN OVER THE WEEKEND. THIS HIGH WILL SLIDE TO
OUR EAST AND NORTHEAST ON EARLY MONDAY, AS A STORM SYSTEM DEVELOPS
ACROSS THE SOUTHERN PLAINS.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A 07Z SURFACE ANALYSIS PLACED LOW PRESSURE OFF THE CAROLINA COAST
WITH A COLD FRONT SNAKING ITS WAY ACROSS THE FAR SOUTHEASTERN UNITED
STATES AND INTO THE EASTERN GULF OF MEXICO. MEANWHILE, HIGH PRESSURE
WAS SITUATED ACROSS THE NORTHERN HIGH PLAINS. AN UPPER AIR ANALYSIS
INDICATED A DEEP TROUGH IN THE EAST WITH MULTIPLE SHORT WAVES MOVING
THROUGH IT, WHILE A RIDGE WAS IN THE WEST. A 300 MB ANALYSIS
INDICATED A STRONG CYCLONICALLY CURVED JET FROM THE MIDWEST TO THE
DEEP SOUTH, WITH ANOTHER JET MAXIMUM EAST OF THE EASTERN SEABOARD.
THE WATER VAPOR IMAGERY SHOWS SEVERAL MIDLEVEL IMPULSES, HOWEVER TWO
ARE MORE DEFINED. ONE IS MOVING OFF THE COAST OF SOUTH CAROLINA AND
HELPING TO STRENGTHEN THE SURFACE LOW WHILE ANOTHER ONE IS DIVING
SOUTHWARD ACROSS THE LOWER MISSISSIPPI VALLEY. THESE IMPULSES WILL
HELP TO MAINTAIN THE EASTERN TROUGH ALONG WITH DEEPENING THE COASTAL
STORM.
DUE TO THE SNOW THAT OCCURRED IN MANY AREAS ON MONDAY AND COLD
TEMPERATURES THIS MORNING, ICY SPOTS WILL BE POSSIBLE THIS MORNING.
THIS WILL ESPECIALLY BE THE CASE ON UNTREATED ROADS, BRIDGES AND
OVERPASSES. WE MAY ISSUE A SPECIAL WEATHER STATEMENT /SPS/ REGARDING
THIS TO HIGHLIGHT THE POSSIBLE HAZARD. OUR WEATHER WILL BE
DOMINATED BY THE PASSAGE OF A FEW SHORT WAVES TODAY, AS WE WATCH
THE COASTAL LOW ORGANIZE WELL TO OUR SOUTH AND THEN TRACK FAIRLY
FAR TO OUR EAST TONIGHT. GIVEN THE POSITION OF THE UPPER-LEVEL
TROUGH, THE MAIN FLOW IS POSITIONED FAIRLY FAR OFF THE EAST COAST,
THEREFORE A CONDUIT FOR THE COASTAL STORM TO TRACK IS EXPECTED TO
ALSO REMAIN WELL EAST OF OUR AREA. A CONCERN WE HAVE THOUGH IS
THAT THE SECOND MIDLEVEL IMPULSE ROUNDING THE BASE OF THE SHARP
TROUGH THIS MORNING MAY BE ABLE TO PULL THE SURFACE LOW A TAD
FARTHER TO THE WEST ALONG THE BAROCLINIC ZONE. THE MODEL GUIDANCE
IS PRETTY MUCH UNANIMOUS THOUGH IN KEEPING THE MEASURABLE
PRECIPITATION EAST OF OUR COASTAL AREAS BUT SOME BRING IT VERY
CLOSE. AS A RESULT, WE WILL CARRY SLIGHT CHC TO LOW CHC POPS FOR
SOME LIGHT SNOW ACROSS THE FAR SOUTHERN ZONES AND ACROSS
SOUTHEASTERN NEW JERSEY ON EASTWARD. ELSEWHERE, WE WILL KEEP IT
DRY WITH ONLY SOME FLURRIES MENTIONED IN THE POCONOS. SINCE THERE
WILL BE A COASTAL STORM TRACKING TO OUR SOUTH AND EAST TODAY AND
TONIGHT, AND A RATHER COLD AIR MASS IS IN PLACE, WE WERE PONDERING
IF ANY OCEAN EFFECT SNOW COULD DEVELOP. THE SETUP DOES NOT LOOK
GOOD AS THE BOUNDARY LAYER FLOW APPEARS TO REMAIN MORE NORTH
INSTEAD OF BACKING TO THE NORTHEAST /WITH SOME SHEAR NOTED/, LIMITING
THE FETCH. THERE IS MOISTURE WITHIN THE BOUNDARY LAYER, ALTHOUGH A
MORE SATURATED LAYER DOES NOT APPEAR DEEP ENOUGH. THEREFORE, WE
ARE NOT FACTORING IN ANY OCEAN MOISTURE BEING TOSSED INLAND TODAY
AND TONIGHT AS THE COASTAL STORM SLIDES ON BY.
THE FORECAST SOUNDINGS SUGGEST THAT THE CONVECTIVE TEMPERATURES ARE
FAIRLY LOW TODAY. THIS COMBINED WITH ENOUGH MOISTURE IN THE
BOUNDARY LAYER, A DEEP/COLD UPPER-LEVEL TROUGH, AND SOME SHORT WAVE
ENERGY AROUND, SHOULD RESULT IN THE DEVELOPMENT OF STRATOCUMULUS.
THE IR SATELLITE IMAGERY EARLY THIS MORNING IS NOT SHOWING MUCH IN
THE WAY OF CLOUDS AROUND, OTHER THAN SOME CIRRUS.
HIGH TEMPERATURES WERE LEANED CLOSER TO THE COLDER NAM MOS FOR MANY
LOCALES GIVEN THE LOOK OF THE FORECAST SOUNDINGS TODAY AS WELL AS
THE ADDED SNOW COVER. FORECAST SOUNDINGS INDICATE WINDS COULD TURN
A BIT GUSTY AT TIMES TODAY WITH VERTICAL MIXING AND THE PRESSURE
GRADIENT TIGHTENING UP, THEREFORE IT WILL TURN BRISK.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/...
THE DEEP UPPER-LEVEL TROUGH WILL REMAIN ACROSS THE EASTERN UNITED
STATES FOR A TIME, HOWEVER A PATTERN CHANGE IS ANTICIPATED AS WE GO
THROUGH WEDNESDAY NIGHT AND THURSDAY. THE TROUGH WILL BE LIFTING OUT
AS ENERGY IN CANADA DIVES FARTHER TO THE WEST. THE COMPUTER MODELS
ALONG WITH THE ENSEMBLES AGREE RATHER WELL ON THE OVERALL LARGER
SCALE PATTERN. AS THE COASTAL LOW SLIDES TO OUR EAST TONIGHT, OUR
FAR SOUTHERN AND EASTERN COUNTIES MAY BE BRUSHED BY A TOUCH OF
LIGHT SNOW. AS A RESULT, WE CARRIED SLIGHT CHC TO LOW CHC POPS
FOR THE FIRST HALF OF THE NIGHT. ELSEWHERE, NO MEASURABLE
PRECIPITATION IS EXPECTED DESPITE SOME SHORT WAVE ENERGY SLIDING
BY. ALTHOUGH, SOME FLURRIES IN THE POCONOS ARE POSSIBLE GIVEN THE
COLD NORTHWESTERLY FLOW, WHICH MAY ALLOW SOME LAKE EFFECT MOISTURE
TO REACH THERE. THE PRESSURE GRADIENT HOLDS UP FOR AWHILE TONIGHT,
THEREFORE A GUSTY WIND SHOULD CONTINUE FOR A TIME, BEFORE
DIMINISHING SOME.
GRADUALLY HIGH PRESSURE BUILDS INTO OUR REGION FROM THE SOUTHWEST
WEDNESDAY NIGHT AND THURSDAY AS THE UPPER TROUGH BEGINS TO LIFT
NORTHEASTWARD. SOME WAA FROM THE MIDWEST TOWARD THE OHIO VALLEY WILL
BE AHEAD OF A FRONTAL BOUNDARY. THE BULK OF THE LIFT ASSOCIATED WITH
A SHORT WAVE IS EXPECTED TO SLIDE ACROSS EASTERN CANADA. THIS COULD
TOSS SOME MORE CLOUDS INTO OUR AREA THOUGH, ESPECIALLY OUR NORTHERN
ZONES WEDNESDAY INTO THURSDAY. THE WAA IS MORE NOTABLE ON THURSDAY
AS THE UPPER TROUGH FLATTENS OUT MORE, ALLOWING OUR WINDS TO BACK A
BIT. THIS WILL ALLOW TEMPERATURES TO REBOUND MORE IN THE AFTERNOON TO
NEAR WHERE WE SHOULD BE FOR THIS TIME OF THE YEAR. WE THEN TURN OUR
ATTENTION TO THE NORTHERN PLAINS AS A SHORT WAVE DIVING
SOUTHEASTWARD BEGINS TO AMPLIFY AN UPPER-LEVEL TROUGH. THIS WILL
DRIVE A COLD FRONT ACROSS THE NORTHERN TIER STATES AND INTO THE
GREAT LAKES AND TOWARD THE NORTHEAST ON FRIDAY.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
THE RETREATING OF THE LARGE UPPER-LEVEL TROUGH IN THE EAST WILL
ALLOW FOR A MODERATION IN THE TEMPERATURE DEPARTMENT TO START THIS
TIME FRAME OFF. THE UPPER-LEVEL FLOW PATTERN IS FAIRLY WELL AGREED
UPON AMONG THE OPERATIONAL MODEL GUIDANCE AS WELL AS THE ENSEMBLES.
THEY BASICALLY ARE GOING WITH A MORE ZONAL FLOW FOR A TIME, BEFORE
MORE TROUGHING BEGINS TO DIG INTO THE GREAT LAKES, NORTHEAST AND MID
ATLANTIC REGIONS. THE LEADING EDGE OF ANOTHER DEVELOPING UPPER-LEVEL
TROUGH WILL BE A SHORT WAVE DIVING SOUTHEASTWARD ACROSS THE MIDWEST
AND GREAT LAKES REGION ON FRIDAY. THE TIMING OF THIS FEATURE
GENERALLY LOOKS GOOD AMONG THE MODELS, ALTHOUGH THE DETAILS SUCH AS
THE THERMAL FIELDS DIFFER SOME. THIS SYSTEM IS PROBABLY MORE OF A
CLIPPER TYPE SYSTEM AS IT TRACKS THROUGH THE GREAT LAKES AND INTO
NEW ENGLAND, AND LOOKS TO BE RATHER MOISTURE STARVED.
AS THIS OCCURS, RISING HEIGHTS ALONG WITH A SOUTHERLY FLOW ACROSS
OUR REGION WILL COMBINE WITH WAA. AS THE SURFACE HIGH IS FORECAST TO
BE TO OUR EAST, WE ARE NOT EXPECTING ANY COLD AIR DAMMING TO OCCUR,
THEREFORE A DECENT MODERATION OF THE AIR MASS IS EXPECTED FOR FRIDAY.
AS THIS SYSTEM CRUISES TO OUR NORTH LATER FRIDAY, IT WILL SWEEP A
COLD FRONT ACROSS OUR REGION. AS THE UPPER-LEVEL TROUGH SHARPENS
WITH THE PASSAGE OF THE ASSOCIATED SHORT WAVE, MUCH COLDER AIR
WILL ONCE AGAIN GET PULLED DOWN INTO OUR AREA UNDER A STRENGTHENING
NORTHWESTERLY FLOW/CAA REGIME. WHILE THE CORE OF THIS COLD AIR
MASS IS EXPECTED TO REMAIN WELL UP TO OUR NORTH, THE COLDER
WEATHER IS FORECAST TO LINGER THROUGH THE WEEKEND AND EARLY NEXT
WEEK. WHAT THEN GETS OUR ATTENTION IS THE TRANSITION THAT TAKES
PLACE AS ENERGY BEGINS TO DIVE ACROSS THE WESTERN STATES AND IS
EJECTED ACROSS THE SOUTHERN STATES. THE MODEL GUIDANCE SUGGESTS
THAT GIVEN THE UPPER-LEVEL PATTERN, A TIGHTENING THERMAL GRADIENT
WILL BE IN PLACE TO OUR SOUTH. THERE ARE INDICATIONS THAT A LARGE
SURFACE HIGH THAT SLIDES ACROSS OUR AREA OVER THE WEEKEND, TURNS
TO THE NORTHEAST AND BECOMES ENTRENCHED OVER SOUTHEASTERN CANADA.
AS THIS OCCURS, MIDLEVEL SHORT WAVE ENERGY ALONG WITH SOME SURFACE
FEATURES INTERACT WITH THE STRENGTHENING BAROCLINIC ZONE TO OUR
SOUTH AND SOUTHWEST. THIS SCENARIO STRONGLY LEANS TOWARDS
OVERRUNNING PRECIPITATION FOR THE MID ATLANTIC REGION PERHAPS AS
EARLY AS LATE IN THE WEEKEND /SUNDAY NIGHT/, BUT ESPECIALLY
STARTING EARLY IN THE WEEK. THIS COULD BE IN THE FORM OF SNOW OR
EVEN A MIX, WHICH WILL ULTIMATELY DEPEND ON THE ATMOSPHERIC
THERMAL PROFILE.
THE ONLY SIGNIFICANT CHANGE WAS TO INCREASE THE HIGH TEMPERATURES
SEVERAL DEGREES ON FRIDAY DUE TO THE WAA AND RETURN FLOW AHEAD OF
THE NEXT COLD FRONT. OTHERWISE, WE BLENDED IN A SMALL PERCENTAGE OF
MOSGUIDE WITH CONTINUITY TO INTRODUCE SOME NEW DATA INTO THE
FORECAST. THIS WAS ESPECIALLY TRUE FOR TEMPERATURES, DEW POINTS AND
WINDS. TEMPERATURES ON SATURDAY MAY ACTUALLY TOP OUT EARLY IN THE
DAY, THEN GRADUALLY FALL. FOR THE MONDAY POTENTIAL, WE CARRIED
CHC POPS FOR SNOW FOR THE NORTHERN INTO THE CENTRAL AREAS, WITH A
GENERIC CHC OF RAIN/SNOW FURTHER SOUTH. THAT IS ALL FOR NOW.
THANKS TO THE SURROUNDING OFFICES FOR THE COLLABORATION EARLY THIS
MORNING. HAVE A GOOD ONE!
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
SFC OBS AND SATELLITE IMAGERY INDICATE JUST A THIN SCT CIRRUS DECK
OVER MOST OF THE TAF SITES EARLY THIS MORNING. WHILE THIS DECK IS
EXPECTED TO BECOME BKN BY DAYBREAK, CEILING HEIGHTS ARE ALL EXPECTED
TO BE VFR. VSBYS HAVE IMPROVED TO VFR AT ALL TAF SITES EXCEPT ACY,
SO HAVE INCLUDED 5SM IN A TEMPO GROUP UNTIL 10Z TO GIVE THIS SITE
JUST A LITTLE LONGER TO IMPROVE. WINDS ARE EXPECTED TO INCREASE
ON TODAY UNDER THE INFLUENCE OF A TIGHTENING GRADIENT BETWEEN A
DEVELOPING COASTAL LOW TO OUR SOUTH AND SOUTHEAST, AND A HIGH
PRESSURE RIDGE WELL TO OUR WEST AND NORTHWEST. NO PRECIPITATION IS
EXPECTED AT THE TAF SITES THROUGH THE NEXT 36 HOURS.
OUTLOOK...
A BRISK NORTHWEST FLOW WILL PREVAIL THROUGH MOST OF WEDNESDAY AS
AN INCREASED GRADIENT WILL EXIST BETWEEN THE OFFSHORE LOW AND HIGH
PRESSURE RIDGING TO OUR SOUTH. THE WINDS ARE EXPECTED TO DIMINISH
LATER WEDNESDAY AS A WEAK AREA OF HIGH PRESSURE TO THE SOUTH NOSES
NORTHWARD. THEN, VFR CONDITIONS ARE ANTICIPATED DURING THE MID TO
LATE PORTION OF THIS WEEK. THE NEXT WEATHER MAKER LOOKS TO BE IN
THE FORM OF A COLD FRONT ARRIVING LATER FRIDAY.
&&
.MARINE...
NORTHWEST WINDS ARE BEGINNING TO PICK UP OVER THE COASTAL WATERS
EARLY THIS MORNING AS THE PRESSURE GRADIENT INCREASES BETWEEN A
DEVELOPING LOW MOVING OFF THE SOUTH CAROLINA COAST AND A HIGH
PRESSURE SYSTEM WELL TO OUR WEST. WILL KEEP THE SCA STARTING TIME AT
11Z, BUT WILL EXTEND THE EXPIRATION TIME TO 15Z WEDNESDAY /AS
OPPOSED TO 11Z/ JUST TO ALLOW MORE TIME FOR WINDS TO SETTLE DOWN A
BIT ON WEDNESDAY MORNING.
NO OTHER SIGNIFICANT WEATHER IS EXPECTED UNTIL A COLD FRONT, UNDER A
FAIRLY BROAD UPPER TROUGH, MOVES THROUGH LATE FRIDAY OR FRIDAY
EVENING.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EST WEDNESDAY FOR ANZ430-431-
450>455.
&&
$$
SYNOPSIS...GORSE
NEAR TERM...GORSE
SHORT TERM...GORSE
LONG TERM...GORSE
AVIATION...MIKETTA
MARINE...MIKETTA
000
FXUS61 KPHI 200121
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
821 PM EST MON JAN 19 2009
.SYNOPSIS...
THE WEAK DISTURBANCE IN THE UPPER ATMOSPHERE HAS PASS OVERHEAD THIS
EVENING AND WILL NO LONGER AFFECT OUR WEATHER. LOW PRESSURE IS
FORECAST TO DEVELOP OVER THE SOUTHEASTERN STATES TONIGHT, AND IT
SHOULD MOVE TO THE NORTHEAST AND OUT TO SEA ON TUESDAY AND TUESDAY
NIGHT. MEANWHILE, HIGH PRESSURE IS EXPECTED TO BUILD INTO OUR
REGION FROM THE WEST FOR THE MID WEEK PERIOD. A COLD FRONT IS
FORECAST TO APPROACH FROM THE NORTHWEST ON FRIDAY AND IT SHOULD
REACH OUR REGION ON FRIDAY NIGHT. HIGH PRESSURE IS ANTICIPATED TO
FOLLOW FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
SNOW HAS ENDED ACROSS THE AREA THIS EVENING AS THE VORT MAX
ASSOCIATED WITH THE SHORT WAVE MOVING ACROSS THE AREA HAS MOVED
THROUGH. BEHIND THIS DISTURBANCE, PRECIPITATION IS NOT EXPECTED
FOR THE REMAINDER OF THE NIGHT. CLOUDS HOWEVER ARE EXPECTED FOR
MUCH OF THE NIGHT, BUT THERE COULD BE A FEW BREAKS DURING THE
OVERNIGHT HOURS. COOLER AND DRIER AIR WILL TRY TO MOVE IN TONIGHT
FROM THE WEST, AND IF WE DO HAVE ANY BREAKS, OUR TEMPERATURES MAY
GO DOWN A LITTLE MORE THAN PREVIOUSLY EXPECTED. THEREFORE WE
LOWERED MIN TEMPERATURES TONIGHT BY ONLY A COUPLE OF DEGREES.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
LOW PRESSURE, PASSING WELL TO OUR SOUTHEAST ON TUESDAY, MAY BRING
SOME CLOUDS TO OUR SOUTHEASTERN COUNTIES. THE PRECIPITATION
ASSOCIATED WITH THE LOW SHOULD REMAIN OFF THE COAST. HOWEVER, WE
HAVE INCLUDED SLIGHT CHANCE POPS FOR SUSSEX COUNTY IN DELAWARE AND
FOR CAPE MAY COUNTY IN NEW JERSEY FOR TUESDAY AFTERNOON INTO TUESDAY
EVENING. ALSO, WE HAVE SLIGHT CHANCE POPS FOR THE COASTAL AREAS OF
ATLANTIC COUNTY IN NEW JERSEY.
HIGH PRESSURE IS FORECAST TO BUILD INTO OUR REGION FROM THE WEST FOR
TUESDAY NIGHT THROUGH THURSDAY. AS A RESULT, WE ARE EXPECTING DRY
WEATHER CONDITIONS AND BELOW NORMAL TEMPERATURES RETURNING TO NEAR
NORMAL DURING THE PERIOD.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A COLD FRONT IS FORECAST TO APPROACH FROM THE NORTHWEST ON FRIDAY
AND IT SHOULD REACH OUR REGION ON FRIDAY NIGHT. THE SYSTEM SHOULD
HAVE A LIMITED AMOUNT OF MOISTURE WITH IT, SO WE WILL SIMPLY CARRY
SOME MENTION OF CLOUDS. WE WILL ALSO INCLUDE SLIGHT CHANCE POPS IN
THE GRAPHICAL FORECAST PRODUCTS.
COLD HIGH PRESSURE IS ANTICIPATED TO FOLLOW FOR THE WEEKEND.
HOWEVER, THE AIR MASS SHOULD NOT BE NEARLY AS COLD AS THE ONE THAT
AFFECTED OUR REGION DURING THE PAST WEEKEND.
AS THE HIGH PASSES OFF THE COAST AND AS LOW PRESSURE BEGINS TO
APPROACH FROM THE WEST EARLY IN THE NEW WEEK, WE ARE ANTICIPATING A
BIT OF A WARMING TREND.
&&
.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
LATEST RADAR IMAGERY SHOWED THAT THE SNOW FROM EARLIER HAS MOVED TO
THE NORTHEAST. AS A RESULT, MOST LOCATIONS HAVE IMPROVED TO VFR, BUT
THERE IS STILL SOME LINGERING MVFR VSBYS. ALSO, KACY IS HOLDING IFR
CIGS AS WELL. EXPECT ALL OF THESE LOCATIONS TO BE VFR BY LATER
TONIGHT. CLOUDS HAVE ESSENTIALLY BECOME SCATTERED ATTM AND EXPECT
CIGS TO REMAIN VFR. WINDS SHOULD START TO INCREASE NOTICEABLY
TUESDAY MORNING UNDER THE INFLUENCE OF THE TIGHTENING GRADIENT
BETWEEN THE DEVELOPING COASTAL LOW TO OUR SOUTH AND SOUTHEAST, AND A
HIGH PRESSURE RIDGE WELL TO OUR WEST AND NORTHWEST.
OUTLOOK...
A COASTAL STORM WILL BE MOVING FROM OFF THE NORTH CAROLINA COAST
TUESDAY TO EAST OF THE NEW JERSEY SHORE TUESDAY NIGHT INTO
WEDNESDAY. THIS SYSTEM LOOKS TO REMAIN FAR ENOUGH TO OUR SOUTH AND
EAST SUCH THAT VFR CONDITIONS WILL OCCUR FOR THE TAF SITES TUESDAY.
KACY AND KMIV MAY DROP A LITTLE LOWER, AS THEY WOULD BE CLOSER TO
THE BETTER LIFT AND MOISTURE.
OTHERWISE, A BRISK NORTHWEST FLOW WILL PREVAIL THROUGH MOST OF
WEDNESDAY AS AN INCREASED GRADIENT WILL EXIST BETWEEN THE OFFSHORE
LOW AND HIGH PRESSURE RIDGING TO OUR SOUTH. THE WINDS ARE EXPECTED
TO DIMINISH LATER WEDNESDAY AS A WEAK AREA OF HIGH PRESSURE TO THE
SOUTH NOSES NORTHWARD. THEN, VFR CONDITIONS ARE ANTICIPATED DURING
THE MID TO LATE PORTION OF THIS WEEK. THE NEXT WEATHER MAKER LOOKS
TO BE IN THE FORM OF A COLD FRONT ARRIVING LATER FRIDAY.
&&
.MARINE...
WINDS HAVE SHIFTED TO THE NW, OR WILL DO SO SHORTLY ACRS THE MARINE
AREA BEHIND A CDFNT. THEN, DEVELOPING LOW PRESSURE OVER THE CENTRAL
MID ATLANTIC STATES TONIGHT WILL MOVE OFFSHORE TUESDAY AND TUESDAY
NIGHT. MOST OF THE SENSIBLE WEATHER WILL STAY TO THE SOUTH OF OUR
AREA, BUT FAR SOUTHERN PARTS OF THE COASTAL WATERS STAND A SMALL
CHANCE OF GETTING SOME PRECIPITATION LATER TUESDAY INTO TUESDAY
NIGHT AS THEY WILL BE BRUSHED BY THE COASTAL LOW. THE FAR BIGGER
STORY WILL BE THE INCREASING GRADIENT TO THE NORTH AND NORTHWEST OF
THE STORM AS IT DEEPENS AGAINST THE RIDGE OF HIGH PRESSURE WELL TO
OUR WEST AND NORTHWEST. MODEL GUIDANCE IS, AND HAS BEEN, FAIRLY
CONSISTENT IN THE TRACK OF THE LOW TO OUR SOUTH AND EAST. (HUMIDITY
AND LIFT ARE OTHER STORIES.) SO, A SMALL CRAFT ADVISORY WILL BE
ISSUED WITH THE AFTERNOON FORECAST FOR TUESDAY AND TUESDAY NIGHT.
WAVEWATCH BUILDS SEAS AT BUOY 44009 TO 5 FEET BY 18Z, SO A FEW HOURS
WILL BE ADDED ON TO THE FRONT SIDE FOR A SAFETY MARGIN. THE ADVISORY
WILL PERSIST THROUGH TUESDAY NIGHT, BUT WILL LIKELY NEED TO BE
EXTENDED THROUGH WEDNESDAY, WHICH LATER FORECASTERS CAN DO IF
NEEDED.
A COUPLE OF UPPER LEVEL DISTURBANCES MAY AFFECT THE AREA THURSDAY
INTO FRIDAY ABOVE SURFACE RIDGING OCCURRING TO OUR SOUTH. SO, NO
SIGNIFICANT WEATHER IS EXPECTED UNTIL A COLD FRONT, UNDER A FAIRLY
BROAD UPPER TROUGH, MOVES THROUGH LATE FRIDAY OR FRIDAY EVENING.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM TUESDAY TO 6 AM EST WEDNESDAY
FOR ANZ430-431-450>455.
&&
$$
SYNOPSIS...IOVINO/ROBERTSON
NEAR TERM...IOVINO/ROBERTSON
SHORT TERM...IOVINO
LONG TERM...IOVINO
AVIATION.../NIERENBERG
MARINE.../NIERENBERG
000
FXUS61 KPHI 192049
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
345 PM EST MON JAN 19 2009
.SYNOPSIS...
A WEAK DISTURBANCE IN THE UPPER ATMOSPHERE WILL PASS OVERHEAD THIS
EVENING. LOW PRESSURE IS FORECAST TO DEVELOP OVER THE SOUTHEASTERN
STATES TONIGHT, AND IT SHOULD MOVE TO THE NORTHEAST AND OUT TO SEA
ON TUESDAY AND TUESDAY NIGHT. MEANWHILE, HIGH PRESSURE IS EXPECTED
TO BUILD INTO OUR REGION FROM THE WEST FOR THE MID WEEK PERIOD. A
COLD FRONT IS FORECAST TO APPROACH FROM THE NORTHWEST ON FRIDAY AND
IT SHOULD REACH OUR REGION ON FRIDAY NIGHT. HIGH PRESSURE IS
ANTICIPATED TO FOLLOW FOR THE WEEKEND.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AN UPPER LEVEL LOW WAS DRIFTING ACROSS WESTERN NEW YORK THIS
AFTERNOON. IT SHOULD REACH THE ADIRONDACKS THIS EVENING, BEFORE
ZIPPING DOWN THE SAINT LAWRENCE RIVER VALLEY AND GETTING ABSORBED BY
THE POLAR VORTEX TONIGHT.
A SHORT WAVE ROTATING AROUND THE LOW SHOULD PASS OVERHEAD THIS
EVENING. AN AREA OF LIGHT SNOW DEVELOPED OUT AHEAD OF THE SHORT
WAVE.
AT 330 PM, LIGHT SNOW WAS FALLING THROUGHOUT MUCH OF SOUTHEASTERN
PENNSYLVANIA, NEW JERSEY AND THE FAR UPPER DELMARVA REGION. THE
BACK EDGE OF THE MAIN AREA OF SNOW HAD ALREADY REACHED THE
CHESAPEAKE BAY REGION, AND IT SHOULD WORK ITS WAY UP THROUGH OUR
FORECAST AREA DURING THE LATE AFTERNOON AND EARLY EVENING HOURS. AS
A RESULT, WE ARE EXPECTING THE SNOW TO END IN EASTERN PENNSYLVANIA
AND NEW JERSEY BY 700 PM. IT SHOULD END EARLIER ON THE UPPER
DELMARVA.
BY MID AFTERNOON, SOME SPOTS IN THE PENNSYLVANIA COUNTIES OF CHESTER
AND MONTGOMERY HAD PICKED UP ONE TO THREE INCHES OF SNOW IN ISOLATED
HEAVIER BANDS OF PRECIPITATION. THOSE SHOULD BE THE HIGHEST AMOUNTS
IN OUR REGION. THE HEAVIER BANDS SHOULD DRIFT NORTHEASTWARD
AFFECTING PARTS OF BUCKS COUNTY IN PENNSYLVANIA, AS WELL AS CENTRAL
AND NORTHERN NEW JERSEY. OTHERWISE, MOST LOCATIONS IN OUR REGION
WILL RECEIVE LESS THAN AN INCH OF SNOW.
ONCE THE SHORT WAVE LIFTS TO OUR NORTHEAST, THE PRECIPITATION WILL
COME TO AN END FOR TONIGHT AND THE CLOUD COVER MAY BREAK A BIT.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
LOW PRESSURE, PASSING WELL TO OUR SOUTHEAST ON TUESDAY, MAY BRING
SOME CLOUDS TO OUR SOUTHEASTERN COUNTIES. THE PRECIPITATION
ASSOCIATED WITH THE LOW SHOULD REMAIN OFF THE COAST. HOWEVER, WE
HAVE INCLUDED SLIGHT CHANCE POPS FOR SUSSEX COUNTY IN DELAWARE AND
FOR CAPE MAY COUNTY IN NEW JERSEY FOR TUESDAY AFTERNOON INTO TUESDAY
EVENING. ALSO, WE HAVE SLIGHT CHANCE POPS FOR THE COASTAL AREAS OF
ATLANTIC COUNTY IN NEW JERSEY.
HIGH PRESSURE IS FORECAST TO BUILD INTO OUR REGION FROM THE WEST FOR
TUESDAY NIGHT THROUGH THURSDAY. AS A RESULT, WE ARE EXPECTING DRY
WEATHER CONDITIONS AND BELOW NORMAL TEMPERATURES RETURNING TO NEAR
NORMAL DURING THE PERIOD.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A COLD FRONT IS FORECAST TO APPROACH FROM THE NORTHWEST ON FRIDAY
AND IT SHOULD REACH OUR REGION ON FRIDAY NIGHT. THE SYSTEM SHOULD
HAVE A LIMITED AMOUNT OF MOISTURE WITH IT, SO WE WILL SIMPLY CARRY
SOME MENTION OF CLOUDS. WE WILL ALSO INCLUDE SLIGHT CHANCE POPS IN
THE GRAPHICAL FORECAST PRODUCTS.
COLD HIGH PRESSURE IS ANTICIPATED TO FOLLOW FOR THE WEEKEND.
HOWEVER, THE AIR MASS SHOULD NOT BE NEARLY AS COLD AS THE ONE THAT
AFFECTED OUR REGION DURING THE PAST WEEKEND.
AS THE HIGH PASSES OFF THE COAST AND AS LOW PRESSURE BEGINS TO
APPROACH FROM THE WEST EARLY IN THE NEW WEEK, WE ARE ANTICIPATING A
BIT OF A WARMING TREND.
&&
.AVIATION /20Z MONDAY THROUGH SATURDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
MARGINAL VFR TO IFR CONDITIONS PREVAILED IN THE SNOW BANDS AT MID
AFTERNOON. THERE WERE TWO MAIN BANDS OF ACTIVITY, ONE FROM
NORTHEASTERN MARYLAND NORTHEASTWARD TO NEW YORK CITY, AND THE OTHER
FROM THE SOUTHERN DELMARVA PENINSULA TO COASTAL SOUTHERN NEW JERSEY
AND OFFSHORE. THE BREAK AREA IN BETWEEN HAD HIGHER VISIBILITIES AND
CEILINGS. FORECASTING WHERE THESE BANDS GO AND HOW THEY CHANGE /
DIMINISH WILL BE PROBLEMATIC...SO WILL FORECAST MARGINAL VFR IN FOG
VARIABLE DOWN TO IFR IN SNOW UNTIL THE WEAK LOW PRESSURE CENTER
RESPONSIBLE FOR THESE LOWER CONDITIONS IS FORECAST TO MOVE TO THE
NORTHEAST AND THROUGH THE AREA LATE THIS AFTERNOON AND EARLY THIS
EVENING. SO, WIDESPREAD IMPROVEMENT IS FORECAST BY 00Z OR 01Z, WITH
CEILINGS AND VISIBILITIES BECOMING VFR. THEN, MODEL AND MOS GUIDANCE
TRY TO SCATTER THE CLOUDS OUT DURING THE OVERNIGHT PERIOD. WITH A
DRIER NORTHWEST FLOW, THIS IS ACCEPTED. WINDS SHOULD START TO
INCREASE NOTICEABLY TUESDAY MORNING UNDER THE INFLUENCE OF THE
TIGHTENING GRADIENT BETWEEN THE DEVELOPING COASTAL LOW TO OUR SOUTH
AND SOUTHEAST, AND A HIGH PRESSURE RIDGE WELL TO OUR WEST AND
NORTHWEST.
OUTLOOK...
A COASTAL STORM WILL BE MOVING FROM OFF THE NORTH CAROLINA COAST
TUESDAY TO EAST OF THE NEW JERSEY SHORE TUESDAY NIGHT INTO
WEDNESDAY. THIS SYSTEM LOOKS TO REMAIN FAR ENOUGH TO OUR SOUTH AND
EAST SUCH THAT VFR CONDITIONS WILL OCCUR FOR THE TAF SITES TUESDAY.
KACY AND KMIV MAY DROP A LITTLE LOWER, AS THEY WOULD BE CLOSER TO
THE BETTER LIFT AND MOISTURE.
OTHERWISE, A BRISK NORTHWEST FLOW WILL PREVAIL THROUGH MOST OF
WEDNESDAY AS AN INCREASED GRADIENT WILL EXIST BETWEEN THE OFFSHORE
LOW AND HIGH PRESSURE RIDGING TO OUR SOUTH. THE WINDS ARE EXPECTED
TO DIMINISH LATER WEDNESDAY AS A WEAK AREA OF HIGH PRESSURE TO THE
SOUTH NOSES NORTHWARD. THEN, VFR CONDITIONS ARE ANTICIPATED DURING
THE MID TO LATE PORTION OF THIS WEEK. THE NEXT WEATHER MAKER LOOKS
TO BE IN THE FORM OF A COLD FRONT ARRIVING LATER FRIDAY.
&&
.MARINE...
LIGHT WINDS OVER THE COASTAL WATERS WERE IN THE PROCESS OF SHIFTING
AROUND AT MID AFTERNOON, AS THE WEAK LOW AFFECTING THE AREA SHIFTS
TO OUR NORTHEAST EARLY THIS EVENING. THIS WILL CAUSE WINDS TO HAUL
AROUND TO THE NORTHWEST TONIGHT. THEN, DEVELOPING LOW PRESSURE OVER
THE CENTRAL MID ATLANTIC STATES TONIGHT WILL MOVE OFFSHORE TUESDAY
AND TUESDAY NIGHT. MOST OF THE SENSIBLE WEATHER WILL STAY TO THE
SOUTH OF OUR AREA, BUT FAR SOUTHERN PARTS OF THE COASTAL WATERS
STAND A SMALL CHANCE OF GETTING SOME PRECIPITATION LATER TUESDAY
INTO TUESDAY NIGHT AS THEY WILL BE BRUSHED BY THE COASTAL LOW. THE
FAR BIGGER STORY WILL BE THE INCREASING GRADIENT TO THE NORTH AND
NORTHWEST OF THE STORM AS IT DEEPENS AGAINST THE RIDGE OF HIGH
PRESSURE WELL TO OUR WEST AND NORTHWEST. MODEL GUIDANCE IS, AND HAS
BEEN, FAIRLY CONSISTENT IN THE TRACK OF THE LOW TO OUR SOUTH AND
EAST. (HUMIDITY AND LIFT ARE OTHER STORIES.) SO, A SMALL CRAFT
ADVISORY WILL BE ISSUED WITH THE AFTERNOON FORECAST FOR TUESDAY AND
TUESDAY NIGHT. WAVEWATCH BUILDS SEAS AT BUOY 44009 TO 5 FEET BY 18Z,
SO A FEW HOURS WILL BE ADDED ON TO THE FRONT SIDE FOR A SAFETY
MARGIN. THE ADVISORY WILL PERSIST THROUGH TUESDAY NIGHT, BUT WILL
LIKELY NEED TO BE EXTENDED THROUGH WEDNESDAY, WHICH LATER
FORECASTERS CAN DO IF NEEDED.
A COUPLE OF UPPER LEVEL DISTURBANCES MAY AFFECT THE AREA THURSDAY
INTO FRIDAY ABOVE SURFACE RIDGING OCCURRING TO OUR SOUTH. SO, NO
SIGNIFICANT WEATHER IS EXPECTED UNTIL A COLD FRONT, UNDER A FAIRLY
BROAD UPPER TROUGH, MOVES THROUGH LATE FRIDAY OR FRIDAY EVENING.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 6 AM TUESDAY TO 6 AM EST
WEDNESDAY FOR ANZ430-431-450>455.
&&
$$
SYNOPSIS/NEAR TERM/SHORT TERM/LONG TERM...IOVINO
000
FXUS61 KPHI 191830
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
130 PM EST MON JAN 19 2009
.SYNOPSIS...
A WEAK FRONT IS FORECAST TO TRACK THROUGH THE AREA LATE TODAY. HIGH
PRESSURE OVER THE MIDWEST WILL THEN SLOWLY BUILD INTO THE AREA
THROUGH THE MIDDLE PART OF THE WEEK. A COLD FRONT IS THEN EXPECTED
TO MOVE THROUGH THE REGION ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LOW PRESSURE IN THE UPPER ATMOSPHERE WILL CONTINUE TO MOVE ACROSS
THE EASTERN GREAT LAKES REGION THIS AFTERNOON. AN UPPER LEVEL SHORT
WAVE EXTENDED FROM THE LOW ACROSS WESTERN PENNSYLVANIA AND DOWN OVER
WEST VIRGINIA LATE THIS MORNING. THE SHORT WAVE WILL ROTATE UP OVER
OUR REGION EARLY THIS EVENING.
AN AREA OF LIGHT SNOW WILL CONTINUE TO DEVELOP OUT AHEAD OF THE
SHORT WAVE. WE ARE EXPECTING UP TO AROUND AN INCH OF SNOW FROM THIS
AFTERNOON INTO THE EARLY EVENING HOURS IN MUCH OF NORTHEASTERN
MARYLAND, DELAWARE, SOUTHERN NEW JERSEY AND EXTREME SOUTHEASTERN
PENNSYLVANIA. FOR AREAS TO THE NORTHWEST, LESSER SNOW AMOUNTS ARE
ANTICIPATED WITH ONLY A TRACE OR A FEW TENTHS OF AN INCH.
THE CLOUD COVER IS EXPECTED TO HOLD THROUGH THE AFTERNOON AND
TEMPERATURES SHOULD RISE BY ONLY A FEW DEGREES AT MOST LOCATIONS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
THE WEAK FRONT WILL MOVE OFF THE COAST THIS EVENING AS THE MID-LEVEL
TROF DIGS A BIT DEEPER. THE TROF WILL THEN SLIDE TO THE EAST TUESDAY
AND TUESDAY NIGHT ALLOWING SURFACE HIGH PRESSURE TO CRAWL TOWARD THE
REGION. THE ONLY POPS IN THIS PERIOD WILL BE VERY EARLY ON AND
ASSOCIATED WITH THE AFOREMENTIONED COLD FRONT. TEMPERATURES WILL RUN
ABOUT 5 TO 10 DEGREES BELOW NORMAL.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
UPPER LEVEL CYCLONIC FLOW CONTINUES INTO THE LONG TERM WITH ANOTHER
SHORT WAVE DIGGING SOUTHEAST FROM THE LAKES. THE COLD AIR IS
ENTRENCHED OVER OUR REGION WEDNESDAY NIGHT. WESTERN ATLANTIC IS
ACTIVE BUT WE GET SOMEWHAT OF A BREAK EXCEPT FOR A WEAK FRONT MOVING
OVER THE RIDGE WEDNESDAY NIGHT AND THROUGH ON THURSDAY. SOME LIGHT
PRECIPITATION IN THE HILLS ESPECIALLY WITH MORE ACTIVE WEATHER
UPSTREAM. A BROAD UPPER TROUGH EXTENDS FROM WESTERN CANADA SOUTH
INTO THE CENTRAL PLAINS THEN EAST. WEAK FRONT WILL BE TO OUR NORTH
THURSDAY NIGHT AS A MASSIVE HIGH PRESSURE CENTERED OVER VANCOUVER
PROVINCE CANADA EXTENDS INTO THE CENTRAL PLAINS. SURFACE BOUNDARY
WILL SLICE THROUGH OUR CWA FRIDAY INTO SATURDAY WITH SCATTERED
SHOWERS. BROAD AREA OF LOW PRESSURE OVER GULF STATES MOVES EAST WITH
MOISTURE SPREADING NORTHEAST FOR SATURDAY INTO SUNDAY. TEMPERATURES
ALOFT REMAIN COLD ENOUGH FOR MOSTLY SNOW.
ONE WOULD FIGURE THAT SOMETHING HAS GOT TO GIVE WITH THIS PATTERN
BY THE END OF THE LONG TERM AND WE FINALLY SEE SOME COASTAL
DEVELOPMENT LIKE THE OLD DAYS SOONER OR LATER.
TEMPERATURES WARM UP THURSDAY AND FRIDAY BUT THEN FALL AGAIN
SATURDAY AND SUNDAY.
&&
.AVIATION /18Z MONDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
IFR TO MARGINAL VFR CONDITIONS PREVAILED IN THE SNOW SHIELD AT MID
AFTERNOON. THERE APPEARED TO BE TWO BANDS OF ACTIVITY, ONE FROM
CENTRAL MARYLAND NORTHEASTWARD TO NORTHERN NEW JERSEY, AND THE OTHER
FROM THE LOWER CHESAPEAKE AREA NORTH-NORTHEASTWARD TO THE JERSEY
SHORE. SO, THERE COULD BE SOME BREAKS IN THE PRECIPITATION THIS
AFTERNOON, BUT GENERAL SNOWFALL WAS FORECAST AS THIS SHOULD BE THE
PREDOMINANT CONDITION. THE BREAK AREA MAY EVEN TRY TO FILL IN
SOMEWHAT AS ACTIVITY MOVES IN FROM NORTHEASTERN VIRGINIA. THE WEAK
LOW PRESSURE CENTER RESPONSIBLE FOR THESE LOWER CONDITIONS IS
FORECAST TO MOVE TO THE NORTHEAST AND THROUGH THE AREA LATE THIS
AFTERNOON AND EARLY THIS EVENING. SO, IMPROVEMENT IS FORECAST BY 00Z
OR 01Z, WITH CEILINGS AND VISIBILITIES BECOMING VFR. THEN, MODEL AND
MOS GUIDANCE TRY TO SCATTER THE CLOUDS OUT DURING THE OVERNIGHT
PERIOD. WITH A DRIER NORTHWEST FLOW, THIS IS ACCEPTED. WINDS SHOULD
START TO INCREASE NOTICEABLY TUESDAY MORNING UNDER THE INFLUENCE OF
THE TIGHTENING GRADIENT BETWEEN THE DEVELOPING COASTAL LOW TO OUR
SOUTH AND SOUTHEAST, AND A HIGH PRESSURE RIDGE WELL TO OUR WEST AND
NORTHWEST.
OUTLOOK...
A COASTAL STORM WILL BE MOVING FROM OFF THE NORTH CAROLINA COAST
TUESDAY TO EAST OF THE NEW JERSEY SHORE TUESDAY NIGHT INTO
WEDNESDAY. THIS SYSTEM LOOKS TO REMAIN FAR ENOUGH TO OUR SOUTH AND
EAST SUCH THAT VFR CONDITIONS WILL OCCUR FOR THE TAF SITES TUESDAY.
KACY AND KMIV MAY DROP A LITTLE LOWER, AS THEY WOULD BE CLOSER TO
THE BETTER LIFT AND MOISTURE.
OTHERWISE, A BRISK NORTHWEST FLOW WILL PREVAIL THROUGH MOST OF
WEDNESDAY AS AN INCREASED GRADIENT WILL EXIST BETWEEN THE OFFSHORE
LOW AND HIGH PRESSURE RIDGING TO OUR SOUTH. THE WINDS ARE EXPECTED
TO DIMINISH LATER WEDNESDAY AS A WEAK AREA OF HIGH PRESSURE TO THE
SOUTH NOSES NORTHWARD. THEN, VFR CONDITIONS ARE ANTICIPATED DURING
THE MID TO LATE PORTION OF THIS WEEK. THE NEXT WEATHER-MAKER LOOKS
TO BE IN THE FORM OF A COLD FRONT ARRIVING LATE FRIDAY.
&&
.MARINE...
A RATHER ACTIVE ATMOSPHERIC PATTERN AS ONE SYSTEM HAS EXITED TO OUR
NORTHEAST EARLY THIS MORNING, THEN WE AWAIT FOR THE NEXT DISTURBANCE
TO ARRIVE THIS AFTERNOON. OVERALL, THE PRESSURE GRADIENT PATTERN IS
FAIRLY LOOSE THEREFORE CONDITIONS ARE NOT EXPECTED TO REACH ADVISORY
CRITERIA TODAY AND TONIGHT. A POTENT UPPER-LEVEL DISTURBANCE THEN
DIVES INTO THE SOUTHEASTERN UNITED STATES TONIGHT. THIS IS FORECAST
TO DEVELOP A COASTAL STORM, WHICH WILL THEN TRACK NORTHEASTWARD ON
TUESDAY. AS IT DOES SO, IT WILL INTENSIFY. IT APPEARS THE STORM WILL
BE FAR ENOUGH TO OUR EAST TO NOT HAVE MUCH OF AN IMPACT
PRECIPITATION-WISE, HOWEVER A TIGHTENING PRESSURE GRADIENT WILL
ALLOW THE SURFACE WINDS TO INCREASE. THE LATEST FORECAST SOUNDINGS
SUGGEST THAT WINDS INCREASE TO ADVISORY CRITERIA LATE TUESDAY
AFTERNOON AND ESPECIALLY TUESDAY NIGHT. WHILE THE WIND FIELD DOES
NOT LOOK OVERLY POTENT, THE STRENGTH OF THIS SYSTEM WILL HAVE TO BE
WATCHED AS ANY DEVIATION WILL RESULT IN A STRONGER OR WEAKER
PRESSURE GRADIENT ACROSS OUR WATERS. AS OF NOW, GALE FORCE WINDS
WILL PROBABLY STAY TO OUR EAST, HOWEVER THIS WILL HAVE TO BE
MONITORED. FOR NOW, WE WILL CONTINUE WITH THE IDEA OF WINDS RAMPING
UP TO ADVISORY CRITERIA LATE IN THE DAY TUESDAY. THIS WOULD BE LATE
IN THE THIRD PERIOD WITH THIS EARLY MORNING ISSUANCE, THEREFORE WE
WILL HOLD OFF ON ISSUING AN ADVISORY BUT CARRY THE CRITERIA IN THE
FORECAST. THE GUSTY CONDITIONS LOOK TO PERSIST THROUGH MOST OF
WEDNESDAY, HOWEVER THE PRESSURE GRADIENT SHOULD BE WANING THROUGH
THE DAY AS THE STORM PULLS FARTHER AWAY AND HIGH PRESSURE ARRIVES
FROM THE WEST.
A COUPLE OF UPPER-LEVEL DISTURBANCES THEN LOOK TO CRUISE NEAR OUR
AREA THURSDAY AND FRIDAY, HOWEVER ATTM IT LOOKS LIKE NO SIGNIFICANT
WEATHER IS EXPECTED. THE EXCEPTION MAY BE A SURFACE COLD FRONT THAT
ARRIVES LATE ON FRIDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KRUZDLO
NEAR TERM.../ IOVINO
SHORT TERM...KRUZDLO
LONG TERM...EBERWINE
AVIATION.../ GORSE/IOVINO
MARINE.../ GORSE
000
FXUS61 KPHI 191700
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1155 AM EST MON JAN 19 2009
.SYNOPSIS...
A WEAK FRONT IS FORECAST TO TRACK THROUGH THE AREA LATE TODAY. HIGH
PRESSURE OVER THE MIDWEST WILL THEN SLOWLY BUILD INTO THE AREA
THROUGH THE MIDDLE PART OF THE WEEK. A COLD FRONT IS THEN EXPECTED
TO MOVE THROUGH THE REGION ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LOW PRESSURE IN THE UPPER ATMOSPHERE WILL CONTINUE TO MOVE ACROSS
THE EASTERN GREAT LAKES REGION THIS AFTERNOON. AN UPPER LEVEL SHORT
WAVE EXTENDED FROM THE LOW ACROSS WESTERN PENNSYLVANIA AND DOWN OVER
WEST VIRGINIA LATE THIS MORNING. THE SHORT WAVE WILL ROTATE UP OVER
OUR REGION EARLY THIS EVENING.
AN AREA OF LIGHT SNOW WILL CONTINUE TO DEVELOP OUT AHEAD OF THE
SHORT WAVE. WE ARE EXPECTING UP TO AROUND AN INCH OF SNOW FROM THIS
AFTERNOON INTO THE EARLY EVENING HOURS IN MUCH OF NORTHEASTERN
MARYLAND, DELAWARE, SOUTHERN NEW JERSEY AND EXTREME SOUTHEASTERN
PENNSYLVANIA. FOR AREAS TO THE NORTHWEST, LESSER SNOW AMOUNTS ARE
ANTICIPATED WITH ONLY A TRACE OR A FEW TENTHS OF AN INCH.
THE CLOUD COVER IS EXPECTED TO HOLD THROUGH THE AFTERNOON AND
TEMPERATURES SHOULD RISE BY ONLY A FEW DEGREES AT MOST LOCATIONS.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
THE WEAK FRONT WILL MOVE OFF THE COAST THIS EVENING AS THE MID-LEVEL
TROF DIGS A BIT DEEPER. THE TROF WILL THEN SLIDE TO THE EAST TUESDAY
AND TUESDAY NIGHT ALLOWING SURFACE HIGH PRESSURE TO CRAWL TOWARD THE
REGION. THE ONLY POPS IN THIS PERIOD WILL BE VERY EARLY ON AND
ASSOCIATED WITH THE AFOREMENTIONED COLD FRONT. TEMPERATURES WILL RUN
ABOUT 5 TO 10 DEGREES BELOW NORMAL.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
UPPER LEVEL CYCLONIC FLOW CONTINUES INTO THE LONG TERM WITH ANOTHER
SHORT WAVE DIGGING SOUTHEAST FROM THE LAKES. THE COLD AIR IS
ENTRENCHED OVER OUR REGION WEDNESDAY NIGHT. WESTERN ATLANTIC IS
ACTIVE BUT WE GET SOMEWHAT OF A BREAK EXCEPT FOR A WEAK FRONT MOVING
OVER THE RIDGE WEDNESDAY NIGHT AND THROUGH ON THURSDAY. SOME LIGHT
PRECIPITATION IN THE HILLS ESPECIALLY WITH MORE ACTIVE WEATHER
UPSTREAM. A BROAD UPPER TROUGH EXTENDS FROM WESTERN CANADA SOUTH
INTO THE CENTRAL PLAINS THEN EAST. WEAK FRONT WILL BE TO OUR NORTH
THURSDAY NIGHT AS A MASSIVE HIGH PRESSURE CENTERED OVER VANCOUVER
PROVINCE CANADA EXTENDS INTO THE CENTRAL PLAINS. SURFACE BOUNDARY
WILL SLICE THROUGH OUR CWA FRIDAY INTO SATURDAY WITH SCATTERED
SHOWERS. BROAD AREA OF LOW PRESSURE OVER GULF STATES MOVES EAST WITH
MOISTURE SPREADING NORTHEAST FOR SATURDAY INTO SUNDAY. TEMPERATURES
ALOFT REMAIN COLD ENOUGH FOR MOSTLY SNOW.
ONE WOULD FIGURE THAT SOMETHING HAS GOT TO GIVE WITH THIS PATTERN
BY THE END OF THE LONG TERM AND WE FINALLY SEE SOME COASTAL
DEVELOPMENT LIKE THE OLD DAYS SOONER OR LATER.
TEMPERATURES WARM UP THURSDAY AND FRIDAY BUT THEN FALL AGAIN
SATURDAY AND SUNDAY.
&&
.AVIATION /17Z MONDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
ANOTHER DISTURBANCE WILL APPROACH OUR AREA THIS AFTERNOON AND IT
SHOULD PASS OVERHEAD EARLY THIS EVENING. CEILINGS WILL CONTINUE TO
LOWER. GIVEN THE TRACK OF THE SYSTEM, THE BEST CHANCE OF SNOW /AN
INCH OR TWO/ WILL BE AT KMIV AND KACY THEREFORE WE WENT WITH
SOMEWHAT LOWER CEILINGS AND HIT THE LOWER VISIBILITIES A LITTLE
HARDER HERE THIS AFTERNOON AND EARLY THIS EVENING. THERE LOOKS TO BE
A PERIOD OF LIGHT SNOW AT LEAST FOR KTTN AND KPHL/KPNE AND KILG
THEREFORE WE INDICATED A PERIOD OF LOW CONDITIONS THIS AFTERNOON AND
EARLY THIS EVENING. FOR KABE AND KRDG, A SNOW SHOWER OR SOME
FLURRIES CANNOT BE RULED OUT THEREFORE WE CARRIED A VCSH TO INDICATE
THE POTENTIAL IN THE AREA FOR AWHILE THIS AFTERNOON AND EVENING.
THE WINDS ARE EXPECTED TO BE RATHER LIGHT TODAY, WITH ONLY A SLIGHT
INCREASE TO 5 TO 10 KNOTS. AS THE SYSTEM MOVES TO OUR EAST EARLY
THIS EVENING, ANY SNOW WILL COME TO AN END AND DRIER AIR WILL ARRIVE
FROM THE WEST. THIS SHOULD SCOUR OUT ANY REMAINING LOW-LEVEL
MOISTURE IN THE EVENING AND WE MAY SEE THE CLOUDS QUICKLY CLEAR OUT.
FOR NOW WE CARRIED A BIT OF LINGERING STRATOCUMULUS AS SOME COLDER
AIR ARRIVES WITH A LIGHT NORTHWESTERLY WIND.
OUTLOOK...
HIGH PRESSURE WILL BE GRADUALLY MOVING TOWARD OUR REGION MONDAY
NIGHT AND TUESDAY, HOWEVER A COASTAL STORM WILL BE TRACKING FROM OFF
THE NORTH CAROLINA COAST TUESDAY TO EAST OF THE NEW JERSEY SHORE
TUESDAY NIGHT INTO WEDNESDAY. THIS SYSTEM LOOKS TO REMAIN FAR ENOUGH
TO OUR EAST TO KEEP LOCAL IMPACTS VERY LOW, ALTHOUGH AN INCREASING
NORTHWESTERLY WIND IS EXPECTED ON TUESDAY WHICH COULD BE A BIT GUSTY
AT TIMES. THE WINDS ARE EXPECTED TO DIMINISH THROUGH WEDNESDAY AS A
WEAK AREA OF HIGH PRESSURE MOVES IN. IN GENERAL, VFR CONDITIONS ARE
ANTICIPATED DURING THE MID TO LATE PORTION OF THIS WEEK UNDER A
NORTHWEST TO WESTERLY FLOW. THE NEXT WEATHER MAKER LOOKS TO BE IN
THE FORM OF A COLD FRONT ARRIVING LATER FRIDAY.
&&
.MARINE...
A RATHER ACTIVE ATMOSPHERIC PATTERN AS ONE SYSTEM HAS EXITED TO OUR
NORTHEAST EARLY THIS MORNING, THEN WE AWAIT FOR THE NEXT DISTURBANCE
TO ARRIVE THIS AFTERNOON. OVERALL, THE PRESSURE GRADIENT PATTERN IS
FAIRLY LOOSE THEREFORE CONDITIONS ARE NOT EXPECTED TO REACH ADVISORY
CRITERIA TODAY AND TONIGHT. A POTENT UPPER-LEVEL DISTURBANCE THEN
DIVES INTO THE SOUTHEASTERN UNITED STATES TONIGHT. THIS IS FORECAST
TO DEVELOP A COASTAL STORM, WHICH WILL THEN TRACK NORTHEASTWARD ON
TUESDAY. AS IT DOES SO, IT WILL INTENSIFY. IT APPEARS THE STORM WILL
BE FAR ENOUGH TO OUR EAST TO NOT HAVE MUCH OF AN IMPACT
PRECIPITATION-WISE, HOWEVER A TIGHTENING PRESSURE GRADIENT WILL
ALLOW THE SURFACE WINDS TO INCREASE. THE LATEST FORECAST SOUNDINGS
SUGGEST THAT WINDS INCREASE TO ADVISORY CRITERIA LATE TUESDAY
AFTERNOON AND ESPECIALLY TUESDAY NIGHT. WHILE THE WIND FIELD DOES
NOT LOOK OVERLY POTENT, THE STRENGTH OF THIS SYSTEM WILL HAVE TO BE
WATCHED AS ANY DEVIATION WILL RESULT IN A STRONGER OR WEAKER
PRESSURE GRADIENT ACROSS OUR WATERS. AS OF NOW, GALE FORCE WINDS
WILL PROBABLY STAY TO OUR EAST, HOWEVER THIS WILL HAVE TO BE
MONITORED. FOR NOW, WE WILL CONTINUE WITH THE IDEA OF WINDS RAMPING
UP TO ADVISORY CRITERIA LATE IN THE DAY TUESDAY. THIS WOULD BE LATE
IN THE THIRD PERIOD WITH THIS EARLY MORNING ISSUANCE, THEREFORE WE
WILL HOLD OFF ON ISSUING AN ADVISORY BUT CARRY THE CRITERIA IN THE
FORECAST. THE GUSTY CONDITIONS LOOK TO PERSIST THROUGH MOST OF
WEDNESDAY, HOWEVER THE PRESSURE GRADIENT SHOULD BE WANING THROUGH
THE DAY AS THE STORM PULLS FARTHER AWAY AND HIGH PRESSURE ARRIVES
FROM THE WEST.
A COUPLE OF UPPER-LEVEL DISTURBANCES THEN LOOK TO CRUISE NEAR OUR
AREA THURSDAY AND FRIDAY, HOWEVER ATTM IT LOOKS LIKE NO SIGNIFICANT
WEATHER IS EXPECTED. THE EXCEPTION MAY BE A SURFACE COLD FRONT THAT
ARRIVES LATE ON FRIDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KRUZDLO
NEAR TERM...IOVINO
SHORT TERM...KRUZDLO
LONG TERM...EBERWINE
AVIATION...GORSE/IOVINO
MARINE...GORSE
000
FXUS61 KPHI 190935
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
430 AM EST MON JAN 19 2009
.SYNOPSIS...
A WEAK FRONT IS FORECAST TO TRACK THROUGH THE AREA LATER TODAY. HIGH
PRESSURE OVER THE MIDWEST WILL THEN SLOWLY BUILD INTO THE AREA
THROUGH THE MIDDLE PART OF THE WEEK. A COLD FRONT IS THEN EXPECTED
TO MOVE THROUGH THE REGION ON FRIDAY.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
A FEW VARIABLES TO DISCUSS THIS MORNING. THE FIRST ONE BEING
TEMPERATURES, THE SECOND ONE BEING QPF, AND THE THIRD BEING SNOW
ACCUMULATIONS LATER THIS AFTERNOON AND EVENING.
TEMPERATURE WISE, WITH THE EXPECTED CLOUD COVER AND THE ANTICIPATED
DYNAMIC COOLING LATER TODAY, WE CHOSE TO UTILIZE THE COOLER MOS
GUIDANCE OR UNDERCUT IT. THE WARMEST TEMPERATURES AS I WRITE ARE
ACTUALLY IN THE POCONOS ACROSS THE HIGHER TERRAIN. THIS DUE TO AN
INVERSION. YOU CAN THANK THE INVERSION FOR THE FREEZING FOG EARLY
THIS MORNING AND THE LOW STRATUS THAT DEVELOPED AS WELL.
AS FOR QPF, THE GFS IS MORE ROBUST THAN EITHER THE ECMWF OR THE WRF.
BUT WITH STAT GUIDANCE REALLY NOT EXCITED ABOUT MUCH PRECIPITATION
EITHER, WE CHOSE TO TAKE THE "LESS" ROUTE RATHER THAN "MORE". WITH
THAT SAID, I PAINTED NO MORE THAN .13" ACROSS THE COASTAL PLAIN AS
THE WEAK FRONT CHUGS ACROSS THE CWA.
THE MORNING INVERSION SHOULD DISSIPATE THIS AFTERNOON. IF THIS
HAPPENS AS PLANNED, PTYPE SHOULDN`T BE MUCH OF AN ISSUE. I
MAINTAINED ALL SNOW, BUT WOULDN`T BE SURPRISED IF A FEW RAIN DROPS
GOT MIXED IN EARLY IN THE PROCESS DOWN ACROSS THE FAR SOUTHERN
ZONES. SNOWFALL ACCUMULATIONS ARE IN LINE WITH HPC, THAT IS, UP TO
AROUND AN INCH EAST OF THE I-95 CORRIDOR. ON ONE SIDE OF THE COIN,
SNOW WILL PROBABLY HAVE A TOUGH TIME STICKING THIS AFTERNOON ON MOST
ROADS BASED ON TIME OF DAY AND INTENSITY. ON THE OTHER SIDE OF THE
COIN IS THE GFS WITH ITS OMEGA AND SNOW GROWTH CROSS-HAIRS THIS
AFTERNOON. IF THIS VERIFIES, THERE COULD BE HEAVIER BURST OF SNOW
AND A MORE EFFICIENT ACCUMULATION.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
THE WEAK FRONT WILL MOVE OFF THE COAST THIS EVENING AS THE MID-LEVEL
TROF DIGS A BIT DEEPER. THE TROF WILL THEN SLIDE TO THE EAST TUESDAY
AND TUESDAY NIGHT ALLOWING SURFACE HIGH PRESSURE TO CRAWL TOWARD THE
REGION. THE ONLY POPS IN THIS PERIOD WILL BE VERY EARLY ON AND
ASSOCIATED WITH THE AFOREMENTIONED COLD FRONT. TEMPERATURES WILL RUN
ABOUT 5 TO 10 DEGREES BELOW NORMAL.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
UPPER LEVEL CYCLONIC FLOW CONTINUES INTO THE LONG TERM WITH ANOTHER
SHORT WAVE DIGGING SOUTHEAST FROM THE LAKES. THE COLD AIR IS
ENTRENCHED OVER OUR REGION WEDNESDAY NIGHT. WESTERN ATLANTIC IS
ACTIVE BUT WE GET SOMEWHAT OF A BREAK EXCEPT FOR A WEAK FRONT MOVING
OVER THE RIDGE WEDNESDAY NIGHT AND THROUGH ON THURSDAY. SOME LIGHT
PRECIPITATION IN THE HILLS ESPECIALLY WITH MORE ACTIVE WEATHER
UPSTREAM. A BROAD UPPER TROUGH EXTENDS FROM WESTERN CANADA SOUTH
INTO THE CENTRAL PLAINS THEN EAST. WEAK FRONT WILL BE TO OUR NORTH
THURSDAY NIGHT AS A MASSIVE HIGH PRESSURE CENTERED OVER VANCOUVER
PROVINCE CANADA EXTENDS INTO THE CENTRAL PLAINS. SURFACE BOUNDARY
WILL SLICE THROUGH OUR CWA FRIDAY INTO SATURDAY WITH SCATTERED
SHOWERS. BROAD AREA OF LOW PRESSURE OVER GULF STATES MOVES EAST WITH
MOISTURE SPREADING NORTHEAST FOR SATURDAY INTO SUNDAY. TEMPERATURES
ALOFT REMAIN COLD ENOUGH FOR MOSTLY SNOW.
ONE WOULD FIGURE THAT SOMETHING HAS GOT TO GIVE WITH THIS PATTERN
BY THE END OF THE LONG TERM AND WE FINALLY SEE SOME COASTAL
DEVELOPMENT LIKE THE OLD DAYS SOONER OR LATER.
TEMPERATURES WARM UP THURSDAY AND FRIDAY BUT THEN FALL AGAIN
SATURDAY AND SUNDAY.
&&
.AVIATION /09Z MONDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
FOLLOWING THE PASSAGE OF THE LIGHT SNOW THAT OCCURRED ACROSS THE
BULK OF THE AREA ON SUNDAY, LIGHT TO CALM WINDS COMBINED WITH AN
ABUNDANCE OF LOW-LEVEL MOISTURE TO RESULT IN FREEZING FOG, SOME OF
WHICH HAS BEEN DENSE /VLIFR/. WE HAVE LOW CONFIDENCE ON THE TIMING
OF THE TRUE IMPROVEMENT OF THE VISIBILITIES AS THERE IS NOT MUCH
WIND FOR AWHILE THIS MORNING. HOWEVER, WE ARE EXPECTING AN
IMPROVEMENT WITH TIME AS A TOUCH OF DRIER AIR BRIEFLY OVERSPREADS
THE AREA. THE CEILINGS TO OUR WEST AND SOUTHWEST HAVE SHOWED
IMPROVEMENT, THEREFORE WE ARE EXPECTING THIS TREND TO CONTINUE
NORTHEASTWARD GRADUALLY EARLY THIS MORNING FOLLOWING THE WEALTH OF
STRATUS /AREAS DOWN TO LIFR/ THAT REFORMED. THE IMPROVEMENTS ARE
EXPECTED TO BE GENERALLY SHORT-LIVED THOUGH AS ANOTHER DISTURBANCE
APPROACHES OUR AREA THIS AFTERNOON. WHILE VFR STRATOCUMULUS WILL BE
AROUND THIS AFTERNOON /MID TO HIGH LEVEL CLOUDS ABOVE/, SOME
LOWERING IS EXPECTED TO OCCUR BY EVENING. SOME ENERGY ROTATING
ACROSS CENTRAL PENNSYLVANIA MAY TOSS A FEW SNOW SHOWERS VERY NEAR
KRDG AND KABE EARLY THIS MORNING. FOR NOW, WE WENT WITH A VCSH,
ESPECIALLY AT KRDG, AND WILL ISSUE AMENDMENTS TO REFLECT
TRENDS/CONDITIONS AS WARRANTED. AS THE NEXT DISTURBANCE THOUGH MOVES
INTO OUR AREA, CEILINGS WILL LOWER A BIT ONCE AGAIN. GIVEN THE TRACK
OF THE SYSTEM, THE BEST CHANCE OF SNOW /AN INCH OR TWO/ WILL BE AT
KMIV AND KACY THEREFORE WE WENT WITH SOMEWHAT LOWER CEILINGS AND HIT
THE LOWER VISIBILITIES A LITTLE HARDER HERE THIS AFTERNOON AND EARLY
THIS EVENING. THERE LOOKS TO BE A PERIOD OF LIGHT SNOW AT LEAST FOR
KTTN AND KPHL/KPNE AND KILG THEREFORE WE INDICATED A PERIOD OF ABOUT
MARGINAL MVFR CONDITIONS LATER THIS AFTERNOON AND EARLY THIS
EVENING. WE MAY NEED TO ADJUST THIS START TIME TO SOONER WITH THE
12Z TAF ISSUANCE. FOR KABE AND KRDG, A SNOW SHOWER OR SOME FLURRIES
CANNOT BE RULED OUT THEREFORE WE CARRIED A VCSH TO INDICATE THE
POTENTIAL IN THE AREA FOR AWHILE THIS AFTERNOON AND EVENING.
THE WINDS ARE EXPECTED TO BE RATHER LIGHT TODAY, WITH ONLY A SLIGHT
INCREASE BY LATE MORNING TO 5 TO 10 KNOTS. AS THE SYSTEM MOVES TO
OUR EAST EARLY THIS EVENING, ANY SNOW WILL COME TO AN END AND DRIER
AIR WILL ARRIVE FROM THE WEST. THIS SHOULD SCOUR OUT ANY REMAINING
LOW-LEVEL MOISTURE IN THE EVENING AND WE MAY SEE THE CLOUDS QUICKLY
CLEAR OUT. FOR NOW WE CARRIED A BIT OF LINGERING STRATOCUMULUS AS
SOME COLDER AIR ARRIVES WITH A LIGHT NORTHWESTERLY WIND.
OUTLOOK...
HIGH PRESSURE WILL BE GRADUALLY MOVING TOWARD OUR REGION MONDAY
NIGHT AND TUESDAY, HOWEVER A COASTAL STORM WILL BE TRACKING FROM OFF
THE NORTH CAROLINA COAST TUESDAY TO EAST OF THE NEW JERSEY SHORE
TUESDAY NIGHT INTO WEDNESDAY. THIS SYSTEM LOOKS TO REMAIN FAR ENOUGH
TO OUR EAST TO KEEP LOCAL IMPACTS VERY LOW, ALTHOUGH AN INCREASING
NORTHWESTERLY WIND IS EXPECTED ON TUESDAY WHICH COULD BE A BIT GUSTY
AT TIMES. THE WINDS ARE EXPECTED TO DIMINISH THROUGH WEDNESDAY AS A
WEAK AREA OF HIGH PRESSURE MOVES IN. IN GENERAL, VFR CONDITIONS ARE
ANTICIPATED DURING THE MID TO LATE PORTION OF THIS WEEK UNDER A
NORTHWEST TO WESTERLY FLOW. THE NEXT WEATHER MAKER LOOKS TO BE IN
THE FORM OF A COLD FRONT ARRIVING LATER FRIDAY.
&&
.MARINE...
A RATHER ACTIVE ATMOSPHERIC PATTERN AS ONE SYSTEM HAS EXITED TO OUR
NORTHEAST EARLY THIS MORNING, THEN WE AWAIT FOR THE NEXT DISTURBANCE
TO ARRIVE THIS AFTERNOON. OVERALL, THE PRESSURE GRADIENT PATTERN IS
FAIRLY LOOSE THEREFORE CONDITIONS ARE NOT EXPECTED TO REACH ADVISORY
CRITERIA TODAY AND TONIGHT. A POTENT UPPER-LEVEL DISTURBANCE THEN
DIVES INTO THE SOUTHEASTERN UNITED STATES TONIGHT. THIS IS FORECAST
TO DEVELOP A COASTAL STORM, WHICH WILL THEN TRACK NORTHEASTWARD ON
TUESDAY. AS IT DOES SO, IT WILL INTENSIFY. IT APPEARS THE STORM WILL
BE FAR ENOUGH TO OUR EAST TO NOT HAVE MUCH OF AN IMPACT
PRECIPITATION-WISE, HOWEVER A TIGHTENING PRESSURE GRADIENT WILL
ALLOW THE SURFACE WINDS TO INCREASE. THE LATEST FORECAST SOUNDINGS
SUGGEST THAT WINDS INCREASE TO ADVISORY CRITERIA LATE TUESDAY
AFTERNOON AND ESPECIALLY TUESDAY NIGHT. WHILE THE WIND FIELD DOES
NOT LOOK OVERLY POTENT, THE STRENGTH OF THIS SYSTEM WILL HAVE TO BE
WATCHED AS ANY DEVIATION WILL RESULT IN A STRONGER OR WEAKER
PRESSURE GRADIENT ACROSS OUR WATERS. AS OF NOW, GALE FORCE WINDS
WILL PROBABLY STAY TO OUR EAST, HOWEVER THIS WILL HAVE TO BE
MONITORED. FOR NOW, WE WILL CONTINUE WITH THE IDEA OF WINDS RAMPING
UP TO ADVISORY CRITERIA LATE IN THE DAY TUESDAY. THIS WOULD BE LATE
IN THE THIRD PERIOD WITH THIS EARLY MORNING ISSUANCE, THEREFORE WE
WILL HOLD OFF ON ISSUING AN ADVISORY BUT CARRY THE CRITERIA IN THE
FORECAST. THE GUSTY CONDITIONS LOOK TO PERSIST THROUGH MOST OF
WEDNESDAY, HOWEVER THE PRESSURE GRADIENT SHOULD BE WANING THROUGH
THE DAY AS THE STORM PULLS FARTHER AWAY AND HIGH PRESSURE ARRIVES
FROM THE WEST.
A COUPLE OF UPPER-LEVEL DISTURBANCES THEN LOOK TO CRUISE NEAR OUR
AREA THURSDAY AND FRIDAY, HOWEVER ATTM IT LOOKS LIKE NO SIGNIFICANT
WEATHER IS EXPECTED. THE EXCEPTION MAY BE A SURFACE COLD FRONT THAT
ARRIVES LATE ON FRIDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...KRUZDLO
NEAR TERM...KRUZDLO
SHORT TERM...KRUZDLO
LONG TERM...EBERWINE
AVIATION...GORSE
MARINE...GORSE
000
FXUS61 KPHI 190241
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
940 PM EST SUN JAN 18 2009
.SYNOPSIS...
LOW PRESSURE FORMING OFF THE VIRGINIA COAST WILL MOVE INTO NEW
ENGLAND OVERNIGHT. ANOTHER LOW PRESSURE SYSTEM WILL GET TRIGGERED BY
AN UPPER AIR DISTURBANCE ALONG THE DELMARVA MONDAY AFTERNOON. THE
COASTAL LOW WILL MOVE OFFSHORE MONDAY EVENING PULLING DOWN ANOTHER
SURGE OF COLD AIR. HIGH PRESSURE OVER THE MID WEST, AND THE OFFSHORE
SYSTEMS WILL MAINTAIN A COLD NORTH TO NORTHWEST FLOW WITH SNOW OR
FLURRIES AT TIMES INTO MID WEEK.
&&
.NEAR TERM /THROUGH MONDAY/...
ITS A TOUGH TIME TRYING TO KEEP TRACK OF ALL THE SHORT WAVES AND
CYCLOGENESIS(ES) GOING ON ALREADY AND THE NEXT COUPLE OF DAYS. WE
MUST SAY THIS WINTER HAS TURNED A PAGE IN WHICH THE SNOW HAS STARTED
TO OVERPERFORM THE MODEL (AND OUR) PROJECTIONS BOTH TIMES TODAY AS
THIS CYCLOGENETIC SNOW HAS PRODUCED ABOUT A QUARTER OF AN INCH TO
ONE INCH ACROSS MOST OF OUR CWA.
FOR THE UPDATE WE WILL CARRY A SOW ENDING BEFORE MIDNIGHT STRIPE FOR
THE COASTAL ZONES AND JUST A CHANCE OF FLURRIES ELSEWHERE. CUR MIN
TEMPERATURES LOOK OK. ONLY OTHER ADJUSTMENT WILL BE TO LOWER WINDS
BASED ON CUR OBS.
BY THE WAY AT LEAST AS FAR AS 12 HOUR FCSTS GO VS THE 00Z RAOBS, THE
GFS VERIFIED BETTER THAN THE NAM WITH THE NEXT SHORT WAVE THAT IS
ENTERING THE OHIO VALLEY.
ANOTHER LOW WILL FORM MID WAY DOWN THE APPALACHIANS AND DELAWARE THE
SURGE OF COLD AIR MOVING INTO ALL AREAS. THE NORTHERN HALF WILL SEE
THE 80H TEMPERATURES DROPPING TO THE NEGATIVE LOW TEENS WHILE
SOUTHERN AREAS WILL BE AROUND -6C. AREA OF SURFACE CONVERGENCE WILL
CONTRIBUTE TO LOW LEVEL UVV AND WEAK FORCING NORTHWEST OF THE
SURFACE LOW OVER WESTERN VIRGINIA. SLIGHT DIFFERENCE IN THE HANDLING
OF THE SURFACE LOW WITH THE NAM MORE AGGRESSIVE IN CLOSING IT OFF
MONDAY AFTERNOON AND MOVING IT OFF THE DELMARVA WITH THE QPF AMOUNTS
OF ONE QUARTER INCH JUST OFF THE DE/NJ COAST. MEANWHILE THE 80H
TEMPERATURES BETWEEN -5 AND -10C. THE GFS ON THE OTHER HAND HAS A
WEAKER CENTER AND ABOUT .2 OF AN INCH. FOLLOWING HPC DISCUSSION AS
THE SITUATION EVOLVES. BOTTOM LINE HOWEVER IS WE MAY SEE SOME HIGHER
ACCUMULATIONS FOR LATE MONDAY ACROSS OUR SOUTHERN CFA THIS TIME. THE
SOUNDINGS SHOW A MIX OF SLEET TURNING TO ALL SNOW LATER IN THE NEAR
TERM PERIOD WHICH IS NOTHING NEW THIS WINTER. STILL TIME TO MAKE ANY
DRASTIC CALL ON ACCUMULATIONS AT THIS POINT. MEANWHILE, TEMPERATURES
ON MONDAY FROM THE LOW TO MID 20S NORTH, AROUND THE FREEZING MARK
CENTRAL AREAS AND NEAR 40 DELMARVA ZONES.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
DEPENDING ON THE DEVELOPING SURFACE LOW AT THE COAST AND THE SPEED
AT WHICH IT MOVES THE SNOW MAY LINGER INTO THE EVENING HOURS. THE
LOW COULD DEEPEN ENOUGH TO GIVE US A 10 TO 15 KNOT SURFACE WIND
OFF THE OCEAN AND PROVIDE SOME MOISTURE SOURCE TO BRING THE
ACCUMULATING SNOW SIMILAR TO AN OCEAN EFFECT SNOW. WE`LL SE. IT`S
BEEN DONE BEFORE BUT NOT MUCH. AREAS THEN TO WATCH WOULD BE PARTS
OF INTERIOR SNJ AND INTERIOR SRN DEL AND EASTERN SHORE.
THE LOW WILL MOVE OFF THE COAST MONDAY EVENING BUT THE WRAP AROUND
PRECIPITATION EXTENDS BACK OVER THE EASTERN HALF OF NEW JERSEY. AN
INCH OR TWO OF SNOW IS POSSIBLE AND I`LL PLAY IT THAT WAY AT THIS
TIME. OUR ADVISORY IS TWO INCHES ACROSS THE SOUTH. IT`LL JUST SHOW
UP IN THE HWO FOR NOW. THE NEW EURO SHOWS DOUBLE WEAK LOW WITH
EVEN WEAKER HIGH OVER DELAWARE BAY, FINE TUNING FOR SURE AND LESS
QPF THAN NAM AND GFS. FOR MONDAY NIGHT THERE IS A VERY TIGHT
THERMAL GRADIENT IN A CORRIDOR FROM SOUTHEAST PA TO THE LOW
OFFSHORE WHICH MOVES OFFSHORE AND THE COLD WINDS AND AIR POUR INTO
THE REGION OVERNIGHT MONDAY AND TUESDAY WITH THE BEST GRADIENT AT
THE SHORE. THE COLD CONTINUES INTO TUESDAY NIGHT ENHANCED BY THE
WINDS WITH SOME OCCASIONAL SNOW SHOWERS.
THE LOW MONDAY NIGHT WILL RANGE FROM 9 NORTH...15 CENTRAL AND 21
NEAR THE COAST. HIGHS FOR TUESDAY 20...29 AND 32. LOW TUESDAY
NIGHT 5 NORTH 13 CENTRAL AND 17 AT THE COAST.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
UPPER LEVEL CYCLONIC FLOW CONTINUES INTO THE LONG TERM WITH
ANOTHER SHORT WAVE DIGGING SOUTHEAST FROM THE LAKES. THE COLD AIR
IS ENTRENCHED OVER OUR REGION WEDNESDAY NIGHT. WESTERN ATLANTIC IS
ACTIVE BUT WE GET SOMEWHAT OF A BREAK EXCEPT FOR A WEAK FRONT
MOVING OVER THE RIDGE WEDNESDAY NIGHT AND THROUGH ON THURSDAY.
SOME LIGHT PRECIPITATION IN THE HILLS ESPECIALLY WITH MORE ACTIVE
WEATHER UPSTREAM. A BROAD UPPER TROUGH EXTENDS FROM WESTERN CANADA
SOUTH INTO THE CENTRAL PLAINS THEN EAST. WEAK FRONT WILL BE TO OUR
NORTH THURSDAY NIGHT AS A MASSIVE HIGH PRESSURE CENTERED OVER
VANCOUVER PROVINCE CANADA EXTENDS INTO THE CENTRAL PLAINS. SURFACE
BOUNDARY WILL SLICE THROUGH OUR CWA FRIDAY INTO SATURDAY WITH
SCATTERED SHOWERS. BROAD AREA OF LOW PRESSURE OVER GULF STATES
MOVES EAST WITH MOISTURE SPREADING NORTHEAST FOR SATURDAY INTO
SUNDAY. TEMPERATURES ALOFT REMAIN COLD ENOUGH FOR MOSTLY SNOW.
ONE WOULD FIGURE THAT SOMETHING HAS GOT TO GIVE WITH THIS PATTERN
BY THE END OF THE LONG TERM AND WE FINALLY SEE SOME COASTAL
DEVELOPMENT LIKE THE OLD DAYS SOONER OR LATER.
TEMPERATURES WARM UP THURSDAY AND FRIDAY BUT THEN FALL AGAIN
SATURDAY AND SUNDAY.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
SCATTERED IFR TO MVFR CONDITIONS WILL PREVAIL FOR A FEW MORE HOURS
ACROSS THE TAF SITES AS THE SNOW TAPPERS OFF ACROSS THE AREA AHEAD
OF AN APPROACHING COLD FRONT. BEHIND THE COLD FONT, PARTIAL CLEARING
SHOULD TAKE PLACE FOR MUCH OF THE AREA FOR THE REMAINDER OF THE
OVERNIGHT HOURS AS WINDS WILL SWITCH TO A WEST TO NORTHWEST
DIRECTION.
VFR WEATHER IS FORECAST FOR THE FIRST HALF OF MONDAY WITH A
NORTHWEST FLOW. BY LATE AFTERNOON TOMORROW, SOME LIGHT SNOW MAY
ACTUALLY MAKE IT TO ALL SITES AND LAST INTO THE EARLY EVENING ON
MONDAY. THERE MAY BE A PERIOD OF MARGINAL VFR CONDITIONS FOR BOTH
CIGS AND VSBYS WITH THE SNOW.
OUTLOOK...
CONDITIONS COULD START OUT WITH MARGINAL VFR WEATHER MONDAY EVENING,
THEN IMPROVE TO VFR OVERNIGHT IN THE WAKE OF THE WAVE AND ATTENDANT
FORCING. GENERAL VFR CONDITIONS ARE EXPECTED THROUGH THE MIDDLE OF
NEXT WEEK IN A NORTHWEST TO WEST FLOW.
&&
.MARINE...
CONDITIONS WILL REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA OVERNIGHT
AND SHOULD REMAIN BELOW SMALL CRAFT ADVISORY CRITERIA THROUGH EARLY
TUESDAY. THEN, AS THE OFFSHORE LOW DEEPENS, WINDS AND WAVES ARE
EXPECTED TO RAMP UP TO ADVISORY CRITERIA, EITHER LATER TUESDAY OR,
MORE LIKELY, TUESDAY NIGHT. THIS WILL BE THE FOURTH OR EVEN FIFTH
PERIOD, SO NO OTHER HEADLINES ARE INCLUDED IN THIS AFTERNOON`S
FORECAST ISSUANCE. THOSE CONDITIONS LOOK TO PERSIST INTO WEDNESDAY
OR WEDNESDAY NIGHT AS HIGH PRESSURE BUILDS WELL TO OUR SOUTH AND THE
GRADIENT FINALLY RELAXES SOMEWHAT BY THURSDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS AFTERNOON FOR
ANZ452>455.
&&
$$
SYNOPSIS...GIGI/EBERWINE
NEAR TERM...GIGI/EBERWINE
SHORT TERM...EBERWINE
LONG TERM...EBERWINE
AVIATION...ROBERTSON AND /
MARINE.../
000
FXUS61 KPHI 190017
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
710 PM EST SUN JAN 18 2009
.SYNOPSIS...
LOW PRESSURE WILL FORM ON AN EASTWARD MOVING COLD FRONT THIS EVENING
WITH A SECOND LOW FORMING ALONG THE DELMARVA MONDAY AFTERNOON. THE
COASTAL LOW WILL MOVE OFFSHORE MONDAY EVENING PULLING DOWN ANOTHER
SURGE OF COLD AIR. HIGH PRESSURE OVER THE MID WEST, AND THE OFFSHORE
SYSTEMS WILL MAINTAIN A COLD NORTH TO NORTHWEST FLOW WITH SNOW OR
FLURRIES AT TIMES INTO MID WEEK.
&&
.NEAR TERM /THROUGH MONDAY/...
ZONES UPDATED TO REFLECT CURRENT SNOW OCCURRING ACROSS THE EASTERN
HALF OF OUR CWA. WE ADDED ACCUMS BASED ON SNOW OBSERVER AND SPOTTER
REPORTS. AFM AND PFM WERE PREVIOUSLY UPDATED.
WELCOME TO THE JANUARY "THAWING OUT". WITHOUT THE WIND AND VERY
COLD TEMPERATURES IT ACTUALLY FEELS PRETTY GOOD OUT THERE. AND,
WE DON`T SEE THE EXTREME COLD RETURNING THIS WEEK. I SAY EXTREME,
BUT NONE OF OUR CLIMATE STATIONS SET ANY RECORD LOW TEMPERATURES.
OUR LATEST PNS HAS THE SNOW WRAP-UP SINCE LAST EVENING. THE 80H JET
CONTRIBUTED TO THE SNOW OVER OUR REGION THIS MORNING AND HAS NOW
SHIFTED INTO SOUTHERN NEW ENGLAND. WINDS HAVE BECOME WSW BUT WILL
BACK AROUND TO THE SOUTHWEST AGAIN THIS AFTERNOON. SECOND AREA OF
SNOW OVER CENTRAL AND WESTERN PENNSYLVANIA AHEAD OF THE GREAT LAKES
LOW, BUT A SECOND WEAKER LOW TO FORM OVER WEST VIRGINIA. THE LOW
WILL MOVE QUICKLY OFFSHORE WITH ANOTHER SHOT OF COLD AIR MOVING IN
BEHIND IT. THERE IS AN AREA OF WEAK TO MODERATE QG FORCING MOVING
WITH THE FRONT THAT DOES WEAKEN AS IT MOVES ACROSS NORTHERN MD TO
THE SHORE. PERHAPS ANOTHER LIGHT COATING IN THE SOUTHERN AREAS AND
LIGHT ADDITIONAL ACCUMULATION NORTH. UNDER THE CLOUD COVER TONIGHT
TONIGHT, TEMPERATURES WILL STILL BE BELOW NORMAL BUT NOT BAD RANGING
FROM THE UPPER TEENS FAR NORTH TO THE MID 20S CENTRAL AREAS AND
UPPER 20S TOWARD THE COAST.
ANOTHER LOW WILL FORM MID WAY DOWN THE APPALACHIANS AND DELAWARE THE
SURGE OF COLD AIR MOVING INTO ALL AREAS. THE NORTHERN HALF WILL SEE
THE 80H TEMPERATURES DROPPING TO THE NEGATIVE LOW TEENS WHILE
SOUTHERN AREAS WILL BE AROUND -6C. AREA OF SURFACE CONVERGENCE WILL
CONTRIBUTE TO LOW LEVEL UVV AND WEAK FORCING NORTHWEST OF THE
SURFACE LOW OVER WESTERN VIRGINIA. SLIGHT DIFFERENCE IN THE HANDLING
OF THE SURFACE LOW WITH THE NAM MORE AGGRESSIVE IN CLOSING IT OFF
MONDAY AFTERNOON AND MOVING IT OFF THE DELMARVA WITH THE QPF AMOUNTS
OF ONE QUARTER INCH JUST OFF THE DE/NJ COAST. MEANWHILE THE 80H
TEMPERATURES BETWEEN -5 AND -10C. THE GFS ON THE OTHER HAND HAS A
WEAKER CENTER AND ABOUT .2 OF AN INCH. FOLLOWING HPC DISCUSSION AS
THE SITUATION EVOLVES. BOTTOM LINE HOWEVER IS WE MAY SEE SOME HIGHER
ACCUMULATIONS FOR LATE MONDAY ACROSS OUR SOUTHERN CFA THIS TIME. THE
SOUNDINGS SHOW A MIX OF SLEET TURNING TO ALL SNOW LATER IN THE NEAR
TERM PERIOD WHICH IS NOTHING NEW THIS WINTER. STILL TIME TO MAKE ANY
DRASTIC CALL ON ACCUMULATIONS AT THIS POINT. MEANWHILE, TEMPERATURES
ON MONDAY FROM THE LOW TO MID 20S NORTH, AROUND THE FREEZING MARK
CENTRAL AREAS AND NEAR 40 DELMARVA ZONES.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
DEPENDING ON THE DEVELOPING SURFACE LOW AT THE COAST AND THE SPEED
AT WHICH IT MOVES THE SNOW MAY LINGER INTO THE EVENING HOURS. THE
LOW COULD DEEPEN ENOUGH TO GIVE US A 10 TO 15 KNOT SURFACE WIND
OFF THE OCEAN AND PROVIDE SOME MOISTURE SOURCE TO BRING THE
ACCUMULATING SNOW SIMILAR TO AN OCEAN EFFECT SNOW. WE`LL SE. IT`S
BEEN DONE BEFORE BUT NOT MUCH. AREAS THEN TO WATCH WOULD BE PARTS
OF INTERIOR SNJ AND INTERIOR SRN DEL AND EASTERN SHORE.
THE LOW WILL MOVE OFF THE COAST MONDAY EVENING BUT THE WRAP AROUND
PRECIPITATION EXTENDS BACK OVER THE EASTERN HALF OF NEW JERSEY. AN
INCH OR TWO OF SNOW IS POSSIBLE AND I`LL PLAY IT THAT WAY AT THIS
TIME. OUR ADVISORY IS TWO INCHES ACROSS THE SOUTH. IT`LL JUST SHOW
UP IN THE HWO FOR NOW. THE NEW EURO SHOWS DOUBLE WEAK LOW WITH
EVEN WEAKER HIGH OVER DELAWARE BAY, FINE TUNING FOR SURE AND LESS
QPF THAN NAM AND GFS. FOR MONDAY NIGHT THERE IS A VERY TIGHT
THERMAL GRADIENT IN A CORRIDOR FROM SOUTHEAST PA TO THE LOW
OFFSHORE WHICH MOVES OFFSHORE AND THE COLD WINDS AND AIR POUR INTO
THE REGION OVERNIGHT MONDAY AND TUESDAY WITH THE BEST GRADIENT AT
THE SHORE. THE COLD CONTINUES INTO TUESDAY NIGHT ENHANCED BY THE
WINDS WITH SOME OCCASIONAL SNOW SHOWERS.
THE LOW MONDAY NIGHT WILL RANGE FROM 9 NORTH...15 CENTRAL AND 21
NEAR THE COAST. HIGHS FOR TUESDAY 20...29 AND 32. LOW TUESDAY
NIGHT 5 NORTH 13 CENTRAL AND 17 AT THE COAST.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
UPPER LEVEL CYCLONIC FLOW CONTINUES INTO THE LONG TERM WITH
ANOTHER SHORT WAVE DIGGING SOUTHEAST FROM THE LAKES. THE COLD AIR
IS ENTRENCHED OVER OUR REGION WEDNESDAY NIGHT. WESTERN ATLANTIC IS
ACTIVE BUT WE GET SOMEWHAT OF A BREAK EXCEPT FOR A WEAK FRONT
MOVING OVER THE RIDGE WEDNESDAY NIGHT AND THROUGH ON THURSDAY.
SOME LIGHT PRECIPITATION IN THE HILLS ESPECIALLY WITH MORE ACTIVE
WEATHER UPSTREAM. A BROAD UPPER TROUGH EXTENDS FROM WESTERN CANADA
SOUTH INTO THE CENTRAL PLAINS THEN EAST. WEAK FRONT WILL BE TO OUR
NORTH THURSDAY NIGHT AS A MASSIVE HIGH PRESSURE CENTERED OVER
VANCOUVER PROVINCE CANADA EXTENDS INTO THE CENTRAL PLAINS. SURFACE
BOUNDARY WILL SLICE THROUGH OUR CWA FRIDAY INTO SATURDAY WITH
SCATTERED SHOWERS. BROAD AREA OF LOW PRESSURE OVER GULF STATES
MOVES EAST WITH MOISTURE SPREADING NORTHEAST FOR SATURDAY INTO
SUNDAY. TEMPERATURES ALOFT REMAIN COLD ENOUGH FOR MOSTLY SNOW.
ONE WOULD FIGURE THAT SOMETHING HAS GOT TO GIVE WITH THIS PATTERN
BY THE END OF THE LONG TERM AND WE FINALLY SEE SOME COASTAL
DEVELOPMENT LIKE THE OLD DAYS SOONER OR LATER.
TEMPERATURES WARM UP THURSDAY AND FRIDAY BUT THEN FALL AGAIN
SATURDAY AND SUNDAY.
&&
.AVIATION /00Z MONNDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
LIGHT SNOW WILL MOVE THROUGH THE AREA DURING THIS EVENING. WINDS
VEERING TO WEST EARLY TONIGHT WITH FRONTAL PASSAGE SHOULD HELP TO
RAISE CEILINGS...BUT SOUNDING STILL INDICATE A GOOD DEAL OF HIGH
CLOUDS OVERNIGHT AND MONDAY MORNING. VFR WEATHER IS FORECAST FOR THE
FIRST HALF OF MONDAY WITH A NORTHWEST FLOW. FOR THE 30 HOUR TAF FOR
KPHL, CONDITIONS WERE LOWERED LATER MONDAY AFTERNOON WITH THE
APPROACH OF ANOTHER WEAK WAVE. IN FACT, WITH SOME LIGHT
PRECIPITATION AMOUNTS SPIT OUT BY THE VARIOUS MODELS, IT WAS DECIDED
TO SIMPLIFY THINGS AND JUST INCLUDE A MARGINAL VFR VISIBILITY AND
CEILING IN SOME LIGHT SNOW BY 21Z MONDAY.
OUTLOOK...
CONDITIONS COULD START OUT WITH MARGINAL VFR WEATHER MONDAY EVENING,
THEN IMPROVE TO VFR OVERNIGHT IN THE WAKE OF THE WAVE AND ATTENDANT
FORCING. GENERAL VFR CONDITIONS ARE EXPECTED THROUGH THE MIDDLE OF
NEXT WEEK IN A NORTHWEST TO WEST FLOW.
&&
.MARINE...
THE SMALL CRAFT ADVISORY WILL BE CONTINUED FOR A FEW MORE HOURS LATE
THIS AFTERNOON DUE TO THE PERSISTENT 5 AND 6 FOOT SEAS AT BUOY 44009.
THESE SEAS ARE FORECAST TO DIMINISH EARLY TONIGHT, THOUGH. THEN,
WINDS AND SEAS ARE GENERALLY FORECAST TO REMAIN BELOW SMALL CRAFT
ADVISORY CRITERIA THROUGH EARLY TUESDAY. THEN, AS THE OFFSHORE LOW
DEEPENS, WINDS AND WAVES ARE EXPECTED TO RAMP UP TO ADVISORY
CRITERIA, EITHER LATER TUESDAY OR, MORE LIKELY, TUESDAY NIGHT. THIS
WILL BE THE FOURTH OR EVEN FIFTH PERIOD, SO NO OTHER HEADLINES ARE
INCLUDED IN THIS AFTERNOON`S FORECAST ISSUANCE. THOSE CONDITIONS
LOOK TO PERSIST INTO WEDNESDAY OR WEDNESDAY NIGHT AS HIGH PRESSURE
BUILDS WELL TO OUR SOUTH AND THE GRADIENT FINALLY RELAXES SOMEWHAT
BY THURSDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS AFTERNOON FOR
ANZ452>455.
&&
$$
SYNOPSIS...EBERWINE
NEAR TERM...GIGI/EBERWINE
SHORT TERM...EBERWINE
LONG TERM...EBERWINE
AVIATION.../
MARINE.../
000
FXUS61 KPHI 182001
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
301 PM EST SUN JAN 18 2009
.SYNOPSIS...
LOW PRESSURE WILL FORM ON AN EASTWARD MOVING COLD FRONT THIS EVENING
WITH A SECOND LOW FORMING ALONG THE DELMARVA MONDAY AFTERNOON. THE
COASTAL LOW WILL MOVE OFFSHORE MONDAY EVENING PULLING DOWN ANOTHER
SURGE OF COLD AIR. HIGH PRESSURE OVER THE MID WEST, AND THE OFFSHORE
SYSTEMS WILL MAINTAIN A COLD NORTH TO NORTHWEST FLOW WITH SNOW OR
FLURRIES AT TIMES INTO MID WEEK.
&&
.NEAR TERM /THROUGH MONDAY/...
WELCOME TO THE JANUARY "THAWING OUT". WITHOUT THE WIND AND VERY
COLD TEMPERATURES IT ACTUALLY FEELS PRETTY GOOD OUT THERE. AND,
WE DON`T SEE THE EXTREME COLD RETURNING THIS WEEK. I SAY EXTREME,
BUT NONE OF OUR CLIMATE STATIONS SET ANY RECORD LOW TEMPERATURES.
OUR LATEST PNS HAS THE SNOW WRAP-UP SINCE LAST EVENING. THE 80H JET
CONTRIBUTED TO THE SNOW OVER OUR REGION THIS MORNING AND HAS NOW
SHIFTED INTO SOUTHERN NEW ENGLAND. WINDS HAVE BECOME WSW BUT WILL
BACK AROUND TO THE SOUTHWEST AGAIN THIS AFTERNOON. SECOND AREA OF
SNOW OVER CENTRAL AND WESTERN PENNSYLVANIA AHEAD OF THE GREAT LAKES
LOW, BUT A SECOND WEAKER LOW TO FORM OVER WEST VIRGINIA. THE LOW
WILL MOVE QUICKLY OFFSHORE WITH ANOTHER SHOT OF COLD AIR MOVING IN
BEHIND IT. THERE IS AN AREA OF WEAK TO MODERATE QG FORCING MOVING
WITH THE FRONT THAT DOES WEAKEN AS IT MOVES ACROSS NORTHERN MD TO
THE SHORE. PERHAPS ANOTHER LIGHT COATING IN THE SOUTHERN AREAS AND
LIGHT ADDITIONAL ACCUMULATION NORTH. UNDER THE CLOUD COVER TONIGHT
TONIGHT, TEMPERATURES WILL STILL BE BELOW NORMAL BUT NOT BAD RANGING
FROM THE UPPER TEENS FAR NORTH TO THE MID 20S CENTRAL AREAS AND
UPPER 20S TOWARD THE COAST.
ANOTHER LOW WILL FORM MID WAY DOWN THE APPALACHIANS AND DELAWARE THE
SURGE OF COLD AIR MOVING INTO ALL AREAS. THE NORTHERN HALF WILL SEE
THE 80H TEMPERATURES DROPPING TO THE NEGATIVE LOW TEENS WHILE
SOUTHERN AREAS WILL BE AROUND -6C. AREA OF SURFACE CONVERGENCE WILL
CONTRIBUTE TO LOW LEVEL UVV AND WEAK FORCING NORTHWEST OF THE
SURFACE LOW OVER WESTERN VIRGINIA. SLIGHT DIFFERENCE IN THE HANDLING
OF THE SURFACE LOW WITH THE NAM MORE AGGRESSIVE IN CLOSING IT OFF
MONDAY AFTERNOON AND MOVING IT OFF THE DELMARVA WITH THE QPF AMOUNTS
OF ONE QUARTER INCH JUST OFF THE DE/NJ COAST. MEANWHILE THE 80H
TEMPERATURES BETWEEN -5 AND -10C. THE GFS ON THE OTHER HAND HAS A
WEAKER CENTER AND ABOUT .2 OF AN INCH. FOLLOWING HPC DISCUSSION AS
THE SITUATION EVOLVES. BOTTOM LINE HOWEVER IS WE MAY SEE SOME HIGHER
ACCUMULATIONS FOR LATE MONDAY ACROSS OUR SOUTHERN CFA THIS TIME. THE
SOUNDINGS SHOW A MIX OF SLEET TURNING TO ALL SNOW LATER IN THE NEAR
TERM PERIOD WHICH IS NOTHING NEW THIS WINTER. STILL TIME TO MAKE ANY
DRASTIC CALL ON ACCUMULATIONS AT THIS POINT. MEANWHILE, TEMPERATURES
ON MONDAY FROM THE LOW TO MID 20S NORTH, AROUND THE FREEZING MARK
CENTRAL AREAS AND NEAR 40 DELMARVA ZONES.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
DEPENDING ON THE DEVELOPING SURFACE LOW AT THE COAST AND THE SPEED
AT WHICH IT MOVES THE SNOW MAY LINGER INTO THE EVENING HOURS. THE
LOW COULD DEEPEN ENOUGH TO GIVE US A 10 TO 15 KNOT SURFACE WIND
OFF THE OCEAN AND PROVIDE SOME MOISTURE SOURCE TO BRING THE
ACCUMULATING SNOW SIMILAR TO AN OCEAN EFFECT SNOW. WE`LL SE. IT`S
BEEN DONE BEFORE BUT NOT MUCH. AREAS THEN TO WATCH WOULD BE PARTS
OF INTERIOR SNJ AND INTERIOR SRN DEL AND EASTERN SHORE.
THE LOW WILL MOVE OFF THE COAST MONDAY EVENING BUT THE WRAP AROUND
PRECIPITATION EXTENDS BACK OVER THE EASTERN HALF OF NEW JERSEY. AN
INCH OR TWO OF SNOW IS POSSIBLE AND I`LL PLAY IT THAT WAY AT THIS
TIME. OUR ADVISORY IS TWO INCHES ACROSS THE SOUTH. IT`LL JUST SHOW
UP IN THE HWO FOR NOW. THE NEW EURO SHOWS DOUBLE WEAK LOW WITH
EVEN WEAKER HIGH OVER DELAWARE BAY, FINE TUNING FOR SURE AND LESS
QPF THAN NAM AND GFS. FOR MONDAY NIGHT THERE IS A VERY TIGHT
THERMAL GRADIENT IN A CORRIDOR FROM SOUTHEAST PA TO THE LOW
OFFSHORE WHICH MOVES OFFSHORE AND THE COLD WINDS AND AIR POUR INTO
THE REGION OVERNIGHT MONDAY AND TUESDAY WITH THE BEST GRADIENT AT
THE SHORE. THE COLD CONTINUES INTO TUESDAY NIGHT ENHANCED BY THE
WINDS WITH SOME OCCASIONAL SNOW SHOWERS.
THE LOW MONDAY NIGHT WILL RANGE FROM 9 NORTH...15 CENTRAL AND 21
NEAR THE COAST. HIGHS FOR TUESDAY 20...29 AND 32. LOW TUESDAY
NIGHT 5 NORTH 13 CENTRAL AND 17 AT THE COAST.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
UPPER LEVEL CYCLONIC FLOW CONTINUES INTO THE LONG TERM WITH
ANOTHER SHORT WAVE DIGGING SOUTHEAST FROM THE LAKES. THE COLD AIR
IS ENTRENCHED OVER OUR REGION WEDNESDAY NIGHT. WESTERN ATLANTIC IS
ACTIVE BUT WE GET SOMEWHAT OF A BREAK EXCEPT FOR A WEAK FRONT
MOVING OVER THE RIDGE WEDNESDAY NIGHT AND THROUGH ON THURSDAY.
SOME LIGHT PRECIPITATION IN THE HILLS ESPECIALLY WITH MORE ACTIVE
WEATHER UPSTREAM. A BROAD UPPER TROUGH EXTENDS FROM WESTERN CANADA
SOUTH INTO THE CENTRAL PLAINS THEN EAST. WEAK FRONT WILL BE TO OUR
NORTH THURSDAY NIGHT AS A MASSIVE HIGH PRESSURE CENTERED OVER
VANCOUVER PROVINCE CANADA EXTENDS INTO THE CENTRAL PLAINS. SURFACE
BOUNDARY WILL SLICE THROUGH OUR CWA FRIDAY INTO SATURDAY WITH
SCATTERED SHOWERS. BROAD AREA OF LOW PRESSURE OVER GULF STATES
MOVES EAST WITH MOISTURE SPREADING NORTHEAST FOR SATURDAY INTO
SUNDAY. TEMPERATURES ALOFT REMAIN COLD ENOUGH FOR MOSTLY SNOW.
ONE WOULD FIGURE THAT SOMETHING HAS GOT TO GIVE WITH THIS PATTERN
BY THE END OF THE LONG TERM AND WE FINALLY SEE SOME COASTAL
DEVELOPMENT LIKE THE OLD DAYS SOONER OR LATER.
TEMPERATURES WARM UP THURSDAY AND FRIDAY BUT THEN FALL AGAIN
SATURDAY AND SUNDAY.
&&
.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
THE WARM ADVECTION / WARM FRONTAL PRECIPITATION AND LOWER CONDITIONS
OF EARLY THIS MORNING TRANSITIONED TO HIGH VFR BROKEN TO OVERCAST IN
THE "WARM" SECTOR AT MIDDAY. AS THE PARENT LOW OVER THE GREAT LAKES
MOVES TO THE EAST AND BRINGS A WEAK COLD FRONT THROUGH OUR TAF SITES
TONIGHT, WE LOOK FOR CONDITIONS TO LOWER SOMEWHAT ONCE AGAIN LATE
THIS AFTERNOON OR BY EARLY EVENING, LIKELY TO VFR STRATOCUMULUS
CEILINGS, AS SOME WEAK FORCING MOVES THROUGH THE REGION. AT EARLY
AFTERNOON, THERE WERE SOME WEAK ECHOES FORMING TO OUR WEST AND
SOUTHWEST. MOS GUIDANCE HAS SOMEWHAT LOWER CEILING VALUES THROUGH
THIS EVENING, THEN IMPROVES THINGS A BIT AGAIN IN THE POST-COLD
FRONTAL ENVIRONMENT. THIS GENERAL PHILOSOPHY WAS FOLLOWED. A
VICINITY REMARK WAS USED TO ALLUDE TO SCATTERED ECHOES...LIGHT
SNOW...MOVING THROUGH THE AREA DURING LATE AFTERNOON AND THIS
EVENING. WINDS VEERING TO WEST EARLY TONIGHT WITH FRONTAL PASSAGE
SHOULD HELP TO RAISE CEILINGS...BUT SOUNDING STILL INDICATE A GOOD
DEAL OF HIGH CLOUDS OVERNIGHT AND MONDAY MORNING. VFR WEATHER IS
FORECAST FOR THE FIRST HALF OF MONDAY WITH A NORTHWEST FLOW. FOR THE
30 HOUR TAF FOR KPHL, CONDITIONS WERE LOWERED LATER MONDAY AFTERNOON
WITH THE APPROACH OF ANOTHER WEAK WAVE. IN FACT, WITH SOME LIGHT
PRECIPITATION AMOUNTS SPIT OUT BY THE VARIOUS MODELS, IT WAS DECIDED
TO SIMPLIFY THINGS AND JUST INCLUDE A MARGINAL VFR VISIBILITY AND
CEILING IN SOME LIGHT SNOW BY 21Z MONDAY.
OUTLOOK...
CONDITIONS COULD START OUT WITH MARGINAL VFR WEATHER MONDAY EVENING,
THEN IMPROVE TO VFR OVERNIGHT IN THE WAKE OF THE WAVE AND ATTENDANT
FORCING. GENERAL VFR CONDITIONS ARE EXPECTED THROUGH THE MIDDLE OF
NEXT WEEK IN A NORTHWEST TO WEST FLOW.
&&
.MARINE...
THE SMALL CRAFT ADVISORY WILL BE CONTINUED FOR A FEW MORE HOURS LATE
THIS AFTERNOON DUE TO THE PERSISTENT 5 AND 6 FOOT SEAS AT BUOY 44009.
THESE SEAS ARE FORECAST TO DIMINISH EARLY TONIGHT, THOUGH. THEN,
WINDS AND SEAS ARE GENERALLY FORECAST TO REMAIN BELOW SMALL CRAFT
ADVISORY CRITERIA THROUGH EARLY TUESDAY. THEN, AS THE OFFSHORE LOW
DEEPENS, WINDS AND WAVES ARE EXPECTED TO RAMP UP TO ADVISORY
CRITERIA, EITHER LATER TUESDAY OR, MORE LIKELY, TUESDAY NIGHT. THIS
WILL BE THE FOURTH OR EVEN FIFTH PERIOD, SO NO OTHER HEADLINES ARE
INCLUDED IN THIS AFTERNOON`S FORECAST ISSUANCE. THOSE CONDITIONS
LOOK TO PERSIST INTO WEDNESDAY OR WEDNESDAY NIGHT AS HIGH PRESSURE
BUILDS WELL TO OUR SOUTH AND THE GRADIENT FINALLY RELAXES SOMEWHAT
BY THURSDAY.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS AFTERNOON FOR
ANZ452>455.
&&
$$
SYNOPSIS...EBERWINE
NEAR TERM...EBERWINE
SHORT TERM...EBERWINE
LONG TERM...EBERWINE
AVIATION.../
MARINE.../
000
FXUS61 KPHI 181630
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1130 AM EST SUN JAN 18 2009
.SYNOPSIS...
AS LOW PRESSURE MOVES SLOWLY NORTHEAST THROUGH THE GREAT LAKES
THIS AFTERNOON, A COLD FRONT TRAILING FROM THE LOW WILL MOVE EAST
AND CROSS THE REGION EARLY TONIGHT. A SECOND WEAK FRONT IS LIKELY
TO CROSS THE AREA MONDAY NIGHT AND EARLY TUESDAY. HIGH PRESSURE
OVER THE MIDWEST WILL BUILD SLOWLY EAST OVER THE REGION THROUGH
THE MIDDLE OF THE UPCOMING WEEK. A COLD FRONT IS EXPECTED TO MOVE
THROUGH FROM THE WEST FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
WARM ADVECTION INDUCED SNOW HAS WANED OVER OUR AREA THIS MORNING,
ALTHOUGH THERE WERE SOME LEFTOVERS OVER THE FAR NORTHERN ZONES AT
LATE MORNING. ANY ADDITIONAL ACCUMULATIONS NORTH SHOULD BE LESS
THAN 1 INCH THIS AFTERNOON.
OTHERWISE, WEAK WARM AIR ADVECTION IS NOTED OVER THE ENTIRE AREA,
BUT WITH DYNAMICS ALOFT LACKING, ANY PRECIPITATION SHOULD REMAIN
LIGHT AND MAINLY OVER THE NORTHERN ZONES. OVER THE SOUTHERN ZONES,
ONLY FLURRIES ARE EXPECTED, WITH SPRINKLES ALSO POSSIBLE IN
SOUTHERN DELAWARE AS TEMPERATURES SHOULD GET CLOSE TO 40 THERE.
FORECAST HIGH TEMPERATURES THIS AFTERNOON WERE LOWERED JUST A BIT
MORE, BASED ON CURRENT TEMPERATURES AND NEW GFS MOS 3 HOURLY
TEMPERATURES.
&&
.SHORT TERM /MONDAY/...
A WEAK COLD FRONT MOVES THROUGH FROM THE WEST. HOWEVER, THE TROUGH
ALOFT IS SLOWER TO MOVE THROUGH AND DOESN`T MOVE THROUGH UNTIL
TUESDAY ACCORDING TO THE LATEST GFS. HOWEVER, AS THE UPPER TROUGH
MOVES EAST, IT IS SLOWLY DRYING OUT. THEREFORE, MAINLY FLURRIES
ARE EXPECTED TONIGHT AND MONDAY.
MAV TEMPS GENLY LOOK REASONABLE.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
UPPER LOW OVER EASTERN CANADA BUT LONG ARM OF THE CYCLONIC FLOW
EXTENDS BACK TOWARD THE MISSISSIPPI RIVER. SEVERAL SHORT WAVES
WILL ROTATE AROUND THE BASE OF THE TROUGH WITH THE FIRST TUESDAY
MORNING WITH SNOW AND -16C AT 80H AND THE NEXT PUSHING THROUGH ON
THURSDAY WITH MORE SNOW. WITH SUCH A COLD AIR MASS THESE ARE
NOTHING MORE THAN "GYPPED CLIPPERS" AND NOT LIKELY TO BRING MUCH
IN THE WAY OF SNOW. FOR THE FIRST TIME IN A LONG TIME...THE 80H
ZERO LINE MOVES INTO WESTERN PENNSYLVANIA BUT IS QUICKLY PUSHED
EAST AND SOUTH OF THE CFA AS ANOTHER LOW RACES ACROSS THE GREAT
LAKES INTO EASTERN NEW YORK WITH MINIMAL THREAT OF PRECIPITATION.
ALTHOUGH NO PRECIPITATION...THIS LOW WILL BE FOLLOWED BY MORE COLD
AIR. ANOTHER HIGH WILL SWEEP ACROSS THE NORTHERN PLAINS WITH THE
COLDEST AIR REMAINING IN CANADA BUT STILL THE -22C AT 80H
MAKES IT AS FAR SOUTH AS AVP-FWN LINE BY SATURDAY MORNING.
WITH THE STRONG NORTH-SOUTH TEMPERATURE GRADIENT...TEMPERATURES
WILL REMAIN BELOW NORTH FROM THE LEHIGH VALLEY AND NORTH AND CLIMB
ABOVE NORMAL THU THROUGH SATURDAY FAR SOUTHERN ZONES. WHILE WE MAY
NOT BE GETTING THE BIG SNOWS...MORE ICE AND SNOW MAY BE IN THE
WORKS OVER THE CENTRAL PLAINS BY THE 27TH.
&&
.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
LOW PRESSURE TO THE WEST AND A SYNOPTIC WARM AIR ADVECTION PATTERN
IN COMBINATION WITH A FEW UPPER VORT MAXS ARE CREATING SOME -SN AND
LOWER CIGS ACROSS CENTRAL AND NE PA EARLY THIS MORNING. KRDG, KABE
AND PERHAPS KTTN WILL HAVE SOME LOWER CONDITIONS UNTIL AROUND 12Z
BEFORE THEY GO BACK TO VFR. OVERALL TODAY WILL BE CLOUDY (VFR CIGS)
AT THE TAF SITES WITH A LIGHT S TO SW WIND. A COLD FRONT WILL CROSS
THE AREA OVERNIGHT WITH SLIGHT CHANCES FOR SOME MORE -SN ACROSS THE
NORTH.
OUTLOOK...
SUN NIGHT AND MUCH OF MON WILL GENERALLY BE MOSTLY CLOUDY WITH VFR
CIGS AND NO PRECIP EXPECTED. SKY CONDITIONS WILL IMPROVE FOR MON
NIGHT AND INTO TUE MOST AREAS WITH BKN CONDITIONS NORTH OF KPHL.
&&
.MARINE...
WINDS AND SEAS ARE SLOWLY BUILDING ACROSS THE WATERS AS THE GUIDANCE
HAS BEEN SUGGESTING THAT IT WOULD. LOOKS LIKE IT WILL COME UP INTO
MARGINAL SMALL CRAFT ADVISORY CRITERIA TODAY. THERE ARE 35 KT
WINDS AT AROUND 925 MB, BUT THE THERMAL PROFILE DOES NOT FAVOR
DEEP MIXING.
WINDS AND SEAS ARE EXPECTED TO DECREASE LATER THIS AFTERNOON AND
REMAIN UNDER SMALL CRAFT ADVISORY RANGE UNTIL THE GRADIENT
TIGHTENS UP LATER MONDAY AND MONDAY NIGHT. STRONGER WINDS ALSO
APPEAR TO BE POSSIBLE TUE NIGHT INTO WED WHEN THE PRESSURE
GRADIENT INCREASES BETWEEN A HIGH MOVING IN FROM THE WEST AND A
LOW OFF THE COAST.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR
ANZ452>455.
&&
$$
SYNOPSIS.../ STAUBER
NEAR TERM.../ STAUBER
SHORT TERM...STAUBER
LONG TERM...EBERWINE
AVIATION.../ O`HARA
MARINE.../ O`HARA
000
FXUS61 KPHI 181451
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
951 AM EST SUN JAN 18 2009
.SYNOPSIS...
AS LOW PRESSURE MOVES SLOWLY NORTHEAST THROUGH THE GREAT LAKES
TODAY, A COLD FRONT TRAILING FROM THE LOW WILL MOVE EAST AND CROSS
THE REGION EARLY TONIGHT. HIGH PRESSURE OVER THE MIDWEST WILL
BUILD SLOWLY EAST OVER THE REGION THE EARLY PART OF THE UPCOMING
WEEK. A COLD FRONT IS EXPECTED TO MOVE THROUGH FROM THE WEST
FRIDAY.
&&
.NEAR TERM /THROUGH TONIGHT/...
WARM ADVECTION INDUCED SNOW DEVELOPED IN SOUTHWEST PENNSYLVANIA
OVERNIGHT AND SPREAD INTO MUCH OF OUR AREA TOWARD SUNRISE. THE
REMNANTS OF THIS ACTIVITY ASSOCIATED WITH A LOW LEVEL WARM FRONT
WERE LEAVING COASTAL NEW JERSEY AND WERE LESSENING OVER THE FAR
NORTHERN ZONES, AS VISIBILTIES WERE STARTING TO IMPROVE. SINCE
THE DYNAMICS ALOFT WERE NOT WELL ORGANIZED, MOST OF THE SNOW HAS
BEEN LIGHT. ACCUMULATIONS OVER THE NORTHERN AREAS HAVE BEEN 1 TO 3
INCHES, AND SINCE NOT MUCH MORE IS EXPECTED, THIS IS WHAT WILL BE
PUT INTO THE ZONES. FARTHER TO THE SOUTH, THERE WERE SOME FLURRIES
AND EVEN A BRIEF PERIOD OF LIGHT SNOW THAT LEFT A DUSTING IN SOME
AREAS.
SO DURING THE REST OF TODAY, WE CONTINUE TO HAVE WEAK WARM AIR
ADVECTION OVER THE ENTIRE AREA, BUT WITH DYNAMICS ALOFT LACKING,
ANY PCPN SHOULD REMAIN LIGHT AND MAINLY OVER THE NORTHERN ZONES.
OVER THE SOUTHERN ZONES, ONLY FLURRIES ARE EXPECTED WITH SPRINKLES
ALSO POSSIBLE IN SRN DE AS TEMPS SHOULD GET CLOSE TO 40 THERE.
FCST HIGH TEMPS TODAY WERE BASED OFF THE LATEST MAV GUIDANCE BUT
WERE CUT SLIGHTLY DUE TO CLOUDS.
&&
.SHORT TERM /MONDAY/...
A WEAK COLD FRONT MOVES THROUGH FROM THE WEST. HOWEVER, THE TROUGH
ALOFT IS SLOWER TO MOVE THROUGH AND DOESNT MOVE THROUGH UNTIL
TUESDAY ACCORDING TO THE LATEST GFS. HOWEVER, AS THE UPPER TROUGH
MOVES EAST, IT IS SLOWLY DRYING OUT. THEREFORE, MAINLY FLURRIES
ARE EXPECTED TONIGHT AND MONDAY.
MAV TEMPS GENLY LOOK REASONABLE.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
UPPER LOW OVER EASTERN CANADA BUT LONG ARM OF THE CYCLONIC FLOW
EXTENDS BACK TOWARD THE MISSISSIPPI RIVER. SEVERAL SHORT WAVES
WILL ROTATE AROUND THE BASE OF THE TROUGH WITH THE FIRST TUESDAY
MORNING WITH SNOW AND -16C AT 80H AND THE NEXT PUSHING THROUGH ON
THURSDAY WITH MORE SNOW. WITH SUCH A COLD AIR MASS THESE ARE
NOTHING MORE THAN "GYPPED CLIPPERS" AND NOT LIKELY TO BRING MUCH
IN THE WAY OF SNOW. FOR THE FIRST TIME IN A LONG TIME...THE 80H
ZERO LINE MOVES INTO WESTERN PENNSYLVANIA BUT IS QUICKLY PUSHED
EAST AND SOUTH OF THE CFA AS ANOTHER LOW RACES ACROSS THE GREAT
LAKES INTO EASTERN NEW YORK WITH MINIMAL THREAT OF PRECIPITATION.
ALTHOUGH NO PRECIPITATION...THIS LOW WILL BE FOLLOWED BY MORE COLD
AIR. ANOTHER HIGH WILL SWEEP ACROSS THE NORTHERN PLAINS WITH THE
COLDEST AIR REMAINING IN CANADA BUT STILL THE -22C AT 80H
MAKES IT AS FAR SOUTH AS AVP-FWN LINE BY SATURDAY MORNING.
WITH THE STRONG NORTH-SOUTH TEMPERATURE GRADIENT...TEMPERATURES
WILL REMAIN BELOW NORTH FROM THE LEHIGH VALLEY AND NORTH AND CLIMB
ABOVE NORMAL THU THROUGH SATURDAY FAR SOUTHERN ZONES. WHILE WE MAY
NOT BE GETTING THE BIG SNOWS...MORE ICE AND SNOW MAY BE IN THE
WORKS OVER THE CENTRAL PLAINS BY THE 27TH.
&&
.AVIATION /15Z SUNDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
LOW PRESSURE TO THE WEST AND A SYNOPTIC WARM AIR ADVECTION PATTERN
IN COMBINATION WITH A FEW UPPER VORT MAXS ARE CREATING SOME -SN AND
LOWER CIGS ACROSS CENTRAL AND NE PA EARLY THIS MORNING. KRDG, KABE
AND PERHAPS KTTN WILL HAVE SOME LOWER CONDITIONS UNTIL AROUND 12Z
BEFORE THEY GO BACK TO VFR. OVERALL TODAY WILL BE CLOUDY (VFR CIGS)
AT THE TAF SITES WITH A LIGHT S TO SW WIND. A COLD FRONT WILL CROSS
THE AREA OVERNIGHT WITH SLIGHT CHANCES FOR SOME MORE -SN ACROSS THE
NORTH.
OUTLOOK...
SUN NIGHT AND MUCH OF MON WILL GENERALLY BE MOSTLY CLOUDY WITH VFR
CIGS AND NO PREIP EXPECTED. SKY CONDITIONS WILL IMPROVE FOR MON
NIGHT AND INTO TUE MOST AREAS WITH BKN CONDITIONS NORTH OF KPHL.
&&
.MARINE...
WINDS AND SEAS ARE SLOWLY BUILDING ACROSS THE WATERS AS THE GUIDANCE
HAS BEEN SUGGESTING THAT IT WOULD. LOOKS LIKE IT WILL COME UP INTO
MARGINAL SMALL CRAFT ADVISORY CRITERIA TODAY. THERE ARE 35 KT
WINDS AT AROUND 925 MB, BUT THE THERMAL PROFILE DOES NOT FAVOR
DEEP MIXING.
WINDS AND SEAS ARE EXPECTED TO DECREASE LATER THIS AFTERNOON AND
REMAIN UNDER SMALL CRAFT ADVISORY RANGEUNTUIL THE GRADIENT
TIGHTENS UP LATER MONDAY AND MONDAY NIGHT. STRONGER WINDS ALSO
APPEAR TO BE POSSIBLE TUE NIGHT INTO WED WHEN THE PRESSURE
GRADIENT INCREASES BETWEEN A HIGH MOVING IN FROM THE WEST AND A
LOW OFF THE COAST.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EST THIS AFTERNOON FOR ANZ431-
452>455.
&&
$$
SYNOPSIS.../ STAUBER
NEAR TERM.../ STAUBER
SHORT TERM...STAUBER
LONG TERM...EBERWINE
AVIATION...O`HARA
MARINE...O`HARA
000
FXUS61 KPHI 180719
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
219 AM EST SUN JAN 18 2009
.SYNOPSIS...
AS LOW PRESSURE MOVES SLOWLY NORTHEAST THROUGH THE GREAT LAKES, A
COLD FRONT TRAILING FROM THE LOW WILL MOVE EAST AND CROSS THE
REGION EARLY TONIGHT. HIGH PRESSURE OVER THE MIDWEST WILL BUILD
SLOWLY EAST OVER THE REGION THE EARLY PART OF THE UPCOMING WEEK.
A COLD FRONT IS EXPECTED TO MOVE THROUGH FROM THE WEST FRIDAY.
&&
.NEAR TERM /THROUGH TODAY/...
WARM ADVECTION INDUCED SNOW DEVELOPED IN SOUTHWEST PA OVERNIGHT
AND SPREAD INTO AREAS FROM RDG-ABE-MMU NORTHWARD. HOWEVER, SINCE
THE DYNAMICS ALOFT WERE NOT ORGANIZED, MOST OF THE SNOW WAS LIGHT.
FARTHER TO THE SOUTH AND INCLUDING THE PHILA METROPOLITAN AREA,
THERE WERE SOME FLURRIES AND EVEN A BRIEF PERIOD OF LIGHT SNOW
THAT LEFT A DUSTING IN SOME AREAS.
THERE WAS AN AREA OF BRIEFLY HEAVIER SNOW THAT DEVELOPED
OVERNIGHT. IT WAS ON THE EDGE OF THE INCOMING UPPER VORTICITY AND
SHOWED UP WELL WHEN OVERLAYED WITH THICKNESSES. THIS IS FCST TO
SHEAR OUT AS IT MOVES BY TO THE N/W OF PHL BEFORE SUNRISE AS FCST
BY BOTH THE NAM/WRF AND THE GFS. DURING THE DAYLIGHT HOURS, WE
CONTINUE TO HAVE WEAK WAA OVER THE ENTIRE AREA, BUT WITH DYNAMICS
ALOFT LACKING, ANY PCPN SHOULD REMAIN LIGHT AND MAINLY OVER THE
NORTHERN ZONES. OVER THE SOUTHERN ZONES, ONLY FLURRIES ARE
EXPECTED WITH SPRINKLES ALSO POSSIBLE IN SRN DE AS TEMPS SHOULD
GET CLOSE TO 40 THERE.
FCST HIGH TEMPS TODAY WERE BASED OFF THE LATEST MAV GUIDANCE BUT
WERE CUT SLIGHTLY DUE TO CLOUD.
&&
.SHORT TERM /TONIGHT THROUGH 6 PM MONDAY/...
A WEAK COLD FRONT MOVES THROUGH FROM THE WEST. HOWEVER, THE TROUGH
ALOFT IS SLOWER TO MOVE THROUGH AND DOESNT MOVE THROUGH UNTIL
TUESDAY ACCORDING TO THE LATEST GFS. HOWEVER, AS THE UPPER TROUGH
MOVES EAST, IT IS SLOWLY DRYING OUT. THEREFORE, MAINLY FLURRIES
ARE EXPECTED TONIGHT AND MONDAY.
MAV TEMPS GENLY LOOK REASONABLE.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
UPPER LOW OVER EASTERN CANADA BUT LONG ARM OF THE CYCLONIC FLOW
EXTENDS BACK TOWARD THE MISSISSIPPI RIVER. SEVERAL SHORT WAVES
WILL ROTATE AROUND THE BASE OF THE TROUGH WITH THE FIRST TUESDAY
MORNING WITH SNOW AND -16C AT 80H AND THE NEXT PUSHING THROUGH ON
THURSDAY WITH MORE SNOW. WITH SUCH A COLD AIR MASS THESE ARE
NOTHING MORE THAN "GYPPED CLIPPERS" AND NOT LIKELY TO BRING MUCH
IN THE WAY OF SNOW. FOR THE FIRST TIME IN A LONG TIME...THE 80H
ZERO LINE MOVES INTO WESTERN PENNSYLVANIA BUT IS QUICKLY PUSHED
EAST AND SOUTH OF THE CFA AS ANOTHER LOW RACES ACROSS THE GREAT
LAKES INTO EASTERN NEW YORK WITH MINIMAL THREAT OF PRECIPITATION.
ALTHOUGH NO PRECIPITATION...THIS LOW WILL BE FOLLOWED BY MORE COLD
AIR. ANOTHER HIGH WILL SWEEP ACROSS THE NORTHERN PLAINS WITH THE
COLDEST AIR REMAINING IN CANADA BUT STILL THE -22C AT 80H
MAKES IT AS FAR SOUTH AS AVP-FWN LINE BY SATURDAY MORNING.
WITH THE STRONG NORTH-SOUTH TEMPERATURE GRADIENT...TEMPERATURES
WILL REMAIN BELOW NORTH FROM THE LEHIGH VALLEY AND NORTH AND CLIMB
ABOVE NORMAL THU THROUGH SATURDAY FAR SOUTHERN ZONES. WHILE WE MAY
NOT BE GETTING THE BIG SNOWS...MORE ICE AND SNOW MAY BE IN THE
WORKS OVER THE CENTRAL PLAINS BY THE 27TH.
&&
.AVIATION /07Z SUNDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
LOW PRESSURE TO THE WEST AND A SYNOPTIC WARM AIR ADVECTION PATTERN
IN COMBINATION WITH A FEW UPPER VORT MAXS ARE CREATING SOME -SN AND
LOWER CIGS ACROSS CENTRAL AND NE PA EARLY THIS MORNING. KRDG, KABE
AND PERHAPS KTTN WILL HAVE SOME LOWER CONDITIONS UNTIL AROUND 12Z
BEFORE THEY GO BACK TO VFR. OVERALL TODAY WILL BE CLOUDY (VFR CIGS)
AT THE TAF SITES WITH A LIGHT S TO SW WIND. A COLD FRONT WILL CROSS
THE AREA OVERNIGHT WITH SLIGHT CHANCES FOR SOME MORE -SN ACROSS THE
NORTH.
OUTLOOK...
SUN NIGHT AND MUCH OF MON WILL GENERALLY BE MOSTLY CLOUDY WITH VFR
CIGS AND NO PREIP EXPECTED. SKY CONDITIONS WILL IMPROVE FOR MON
NIGHT AND INTO TUE MOST AREAS WITH BKN CONDITIONS NORTH OF KPHL.
&&
.MARINE...
WINDS AND SEAS ARE SLOWLY BUILDING ACROSS THE WATERS AS THE GUIDANCE
HAS BEEN SUGGESTING THAT IT WOULD. LOOKS LIKE IT WILL COME UP SHORT
OF SCA CRITERIA EARLY TODAY. I WILL PROBABLY MENTION A FEW G25 IN
THE 4AM CWF THOUGH. THERE ARE 35 KT WINDS AT AROUND 925 MB, BUT THE
THERMAL PROFILE DOES NOT FAVOR DEEP MIXING.
WINDS ARE EXPECTED TO DECREASE LATER THIS MORNING AND REMAIN WELL
LESS THAN SCA RANGE FOR THE NEXT FEW DAYS. NEXT CHANCE OF SEEING THE
SCA FLAG WILL BE TUE NIGHT INTO WED WHEN THE PRESSURE GRADIENT
INCREASES BETWEEN A HIGH MOVING IN FROM THE WEST AND A LOW OFF THE
COAST.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...STAUBER
NEAR TERM...STAUBER
SHORT TERM...STAUBER
LONG TERM...EBERWINE
AVIATION...O`HARA
MARINE...O`HARA
000
FXUS61 KPHI 180119
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
820 PM EST SAT JAN 17 2009
.SYNOPSIS...
ARCTIC HIGH WILL MOVE OFFSHORE OVERNIGHT AND ALLOW BOTH CLOUDS AND
SOME LIGHT PRECIPITATION TO MOVE ALONG WITH AN APPROACHING LOW
PRESSURE. THE LOW...OVER THE GREAT LAKES WILL MOVE TO WESTERN NEW
YORK WITH A WEAKER EXTENSION OF IT JUST OFF THE DELMARVA. THE
OFFSHORE LOW WILL BECOME THE PRIMARY ONE AND THEN RACE TO NOVA
SCOTIA MONDAY AFTERNOON. THE DEPARTING LOW...AND APPROACHING HIGH
PRESSURE WILL MAINTAIN A COLD NORTHWEST FLOW WITH OCCASIONAL
FLURRIES OR LIGHT SNOW FROM TIME TO TIME INTO TUESDAY NIGHT. THE
ARCTIC COLD WILL BE REPLACED GRADUALLY WITH NEAR SEASONAL
TEMPERATURES BY MID WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
BASED ON THE 18Z MODEL RUNS WE ARE GOING TO UP THE POPS...SNOW
ACCUMS AND GEOGRAPHICAL EXTENT SLIGHTLY FOR THE FIRST SHOT OF SNOW
TONIGHT.
COMPARING THE ACTUAL SOUNDINGS AND MODEL FORECASTS WE ARE FINDING
THAT THE GFS FORECAST 850MB TEMPS UPSTREAM ARE VERIFYING OK. ITS
ONLY ONE LEVEL, BUT THE FORECAST OF MOISTURE AT THAT LEVEL IS
OVERDONE. THIS HOLDS ALL THE WAY TO THE GULF COAST. GETTING TO THE
GULF COAST, THE GFS HAS OVERDONE THE START OF THE PCPN, NOT MUCH
THERE YET. ITS SUPPOSE TO DEVELOP THIS EVENING AND SO FAR ITS NOT
AHEAD OF SCHEDULE. THE SAME CAN BE SAID FOR THE PCPN THAT IS FCST TO
DEVELOP EAST OF HATTERAS. THE FORMER IS THE MOISTURE THAT IS
FORECAST TO SWING SE OR ALONG THE COAST OF OUR CWA SUNDAY NIGHT. THE
OTHER SUNDAY DRIVER IS THE STRONG SHORT WAVE THAT WAS IN NORTHERN
CANADA LAST NIGHT AND ENTERING NORTH DAKOTA RIGHT NOW. THE MODELS
ARE HANDLING THIS FEATURE QUITE WELL. UNLESS THERE IS AN
ACCELERATION IN THE 00Z RUNS THIS FEATURE WOULD BE A HALF DAY LATE
AND A DOLLAR SHORT FROM PHASING WITH THE GULF COAST MOISTURE FOR US.
BUT GETTING BACK TO TONIGHT. ALL OF THE NUMERICAL GUIDANCE IS KEYING
ON DEVELOPING/ADVECTING PCPN OVER OUR THE PA PART OF OUR CWA
OVERNIGHT. THIS IS ALWAYS A TOUGH ONE TO FORECAST BECAUSE ITS NOT A
CASE OF FOLLOWING A FEATURE FROM POINT A TO POINT B AS IT JUST
DEVELOPS. IF WE LOOK AT THE GFS DIAGS THERE IS OK ISENTROPIC LIFT
AOB 700MB AND THE JET STREAM POSITION IS PRETTY GOOD. BUT UPSTREAM
SFC DEW POINTS ON OUR SIDE OF THE APPALACHIANS ARE PRETTY LOW AND
THE GFS FORECAST DEW POINTS AT BOTH 925MB AND 850MB ARE HIGHER (TOO
MOIST) THAN WHAT THE SOUNDINGS ARE SHOWING. THE SAME HOLDS FOR THE
WRF-NMM WHICH WENT TO THE PLOWS IN THE SUSQ VLY ON THE 18Z RUN.
SO THE UPSHOT FOR NOW IS TO RESPECT THE MODEL DYNAMICS WHICH ARE
DECENT (2 STEPS FORWARD) BUT TAKE INTO CONSIDERATION IT IS DRIER
THAN WHAT THE MODELS THINK (1 STEP BACKWARD) WITH THIS UPDATE. WE
WILL LOOK AT CURRENT TEMPS. WITH SKY COVER IN PLACE, WE EXPECT
TEMPERATURES TO HOLD STEADY OR RISE OVERNIGHT.
NO CHANGES TO SUNDAY. HIGHS FOR SUNDAY 25 TO 40 DEGREES. THERE IS A
MENTION OF RAIN FOR A TIME IN THE SOUTH AND EASTERN ZONES. HOWEVER,
THE AIR IS COLD ALOFT AND IF THE INTENSITY IS OTHER THAN LIGHT,
EVAPORATIONAL COOLER COULD CHANGE THE RAIN OVER TO SNOW BUT RIGHT
NOW PLAYING IT AS A PRIMARILY RAIN EVENT EAST.
THE MODEL SOUNDINGS SUPPORT A SHALLOW LAYER OF WARM AIR WITH
SURFACE TEMPERATURES BETWEEN +2 AND +4 C. WE`LL KEEP AN EYE ON
THAT OCCURRING.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY/...
IN THE EVENING SUNDAY IF THERE IS ANY RAIN FALLING IT WILL CHANGE
BACK TO SNOW AS A SECONDARY LOW SPAWNS OVER THE WEST VIRGINIA
PANHANDLE AND MOVES OFFSHORE LATE. THIS WILL PULL COLDER AIR BACK
INTO THE CFA AND SET THE STAGE FOR MORE FRESH NORTHWEST COLD WINDS
BUT NOT AS COLD AS PAST FEW DAYS. THE BROAD UPPER TROUGH IS OVER
US AND MAINTAINING A CYCLONIC FLOW WITH OCCASIONAL SNOW FOR SUNDAY
NIGHT INTO MONDAY. FOR THE NORTHERN ZONES HAVE MENTIONED
ACCUMULATIONS OF AN INCH FOR TWO OR THREE PERIODS. NOT OUT OF THE
QUESTION BUT PERHAPS THE LONG LASTING EVENT IF DYNAMICS FAVORING A
PARTICULAR SPOT MAY YIELD A LITTLE MORE SNOW.
LOW SUNDAY NIGHT 12 TO 28. HIGHS ON MONDAY 19 TO 34. COUNTING
SEVERAL INCHES OF FRESH SNOW AND GOOD COLD AIR ADVECTION.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
UPPER LOW OVER EASTERN CANADA BUT LONG ARM OF THE CYCLONIC FLOW
EXTENDS BACK TOWARD THE MISSISSIPPI RIVER. SEVERAL SHORT WAVES
WILL ROTATE AROUND THE BASE OF THE TROUGH WITH THE FIRST TUESDAY
MORNING WITH SNOW AND -16C AT 80H AND THE NEXT PUSHING THROUGH ON
THURSDAY WITH MORE SNOW. WITH SUCH A COLD AIR MASS THESE ARE
NOTHING MORE THAN "GYPPED CLIPPERS" AND NOT LIKELY TO BRING MUCH
IN THE WAY OF SNOW. FOR THE FIRST TIME IN A LONG TIME...THE 80H
ZERO LINE MOVES INTO WESTERN PENNSYLVANIA BUT IS QUICKLY PUSHED
EAST AND SOUTH OF THE CFA AS ANOTHER LOW RACES ACROSS THE GREAT
LAKES INTO EASTERN NEW YORK WITH MINIMAL THREAT OF PRECIPITATION.
ALTHOUGH NO PRECIPITATION...THIS LOW WILL BE FOLLOWED BY MORE COLD
AIR. ANOTHER HIGH WILL SWEEP ACROSS THE NORTHERN PLAINS WITH THE
COLDEST AIR REMAINING IN CANADA BUT STILL THE -22C AT 80H
MAKES IT AS FAR SOUTH AS AVP-FWN LINE BY SATURDAY MORNING.
WITH THE STRONG NORTH-SOUTH TEMPERATURE GRADIENT...TEMPERATURES
WILL REMAIN BELOW NORTH FROM THE LEHIGH VALLEY AND NORTH AND CLIMB
ABOVE NORMAL THU THROUGH SATURDAY FAR SOUTHERN ZONES. WHILE WE MAY
NOT BE GETTING THE BIG SNOWS...MORE ICE AND SNOW MAY BE IN THE
WORKS OVER THE CENTRAL PLAINS BY THE 27TH.
&&
.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
ARCTIC HIGH PRESSURE MOVING OFF THE EAST COAST WILL BE FOLLOWED
TONIGHT BY LOW PRESSURE MOVING EASTWARD THROUGH THE GREAT LAKES. A
WARM FRONTAL FEATURE SEEMS TO FORM SOUTHEASTWARD INTO THE CENTRAL
MID ATLANTIC AREA, WHICH THEN LIFTS NORTHWARD THROUGH OUR AREA LATER
TONIGHT AND SUNDAY MORNING. THE NAM EVEN PRINTS OUT AN OFFSHORE
SECONDARY LOW BY 12Z, WITH THE GFS FOLLOWING WITH A WEAK LOW
EAST-NORTHEAST OF US BY 18Z SUNDAY. THESE UNIMPRESSIVE WEATHER
FEATURES SEEM TO SUGGEST THAT THE MOS GUIDANCE HAS A HANDLE ON
THINGS WITH CHANCE PROBABILITIES FOR OUR CENTRAL TAF SITES, PERHAPS
A BIT HIGHER PROBABILITIES (AND WITH LOWER CONDITIONS) FOR THE
NORTHERN TWO SITES, AND LESSER CHANCES SOUTH. SO, A TEMPO GROUP WAS
INSERTED LATE TONIGHT AND EARLY SUNDAY FOR MARGINAL VFR CONDITIONS,
EVEN A TEMPORARY IFR PERIOD FOR ABE AND RDG IN LIGHT SNOW COINCIDENT
WITH THE APPROACH AND PASSAGE OF THE BEST WARM FRONTAL LIFT.
OTHERWISE, WARM ADVECTION GENERATED A RAPID ADVECTION OF MID CLOUDS
INTO THE AREA FROM THE WEST AT EARLY AFTERNOON, AND THIS WILL BE
FOLLOWED BY LOWER MIDDLE LEVEL CLOUDS LATER THIS AFTERNOON AND THIS
EVENING, AND THEN BY (MOSTLY) VFR STRATOCUMULUS LATER TONIGHT WHICH
ARE FORECAST TO CONTINUE SUNDAY.
OUTLOOK...
THE 12Z GFS AND NAM RUNS FAILED TO DEVELOP MUCH COASTAL
FRONTOGENESIS SUNDAY NIGHT INTO MONDAY, SO VFR CONDITIONS LOOK
LIKELY FOR THOSE TIMES AS WELL, AS SUGGESTED BY MOS GUIDANCE. THEN,
A BRISK WEST TO WEST-NORTHWEST FLOW MONDAY MAY BECOME MORE NORTHWEST
MONDAY NIGHT AS LOW PRESSURE DEVELOPS ON THE OFFSHORE FRONT. HIGH
PRESSURE MAY RIDGE IN, AT LEAST TO OUR SOUTH, FOR LATER IN THE WEEK.
&&
.MARINE...
A RETURN TO A SOUTHERLY FLOW TONIGHT IS PROGGED TO BECOME MODERATE
OVERNIGHT. 925 HPA WINDS ACTUALLY INCREASE TO ABOUT 30 KNOTS, BUT
THIS ALL SHOULD NOT MIX TO THE SURFACE. WAVEWATCH DOES INDEED
FORECAST SEAS AT BUOY 44009 UP TO 5 FEET STARTING EARLY SUNDAY AND
LASTING UNTIL DARK. AT THIS TIME, SEAS ON THE OCEAN WILL BE CAPPED
AT 4 FEET, WITH AN OCCASIONAL GUST TO 25 KNOTS, SO A SMALL CRAFT
ADVISORY WILL NOT BE ISSUED FOR OUR COASTAL WATERS AT THIS TIME FOR
LATE TONIGHT AND SUNDAY. HOWEVER, LATER FORECASTERS MAY NEED TO
ISSUE ONE IF WINDS AND SEAS INCREASE SLIGHTLY.
THEN, IN THE WAKE OF THE FRONT MONDAY, THE GRADIENT DOES INCREASE
FOR MONDAY INTO TUESDAY, ESPECIALLY MONDAY NIGHT WHEN THE OFFSHORE
LOW DEEPENS. AT THIS TIME, A FOURTH PERIOD SMALL CRAFT ADVISORY WILL
NOT BE ISSUED. THE GRADIENT REMAINS RATHER STRONG THROUGH WEDNESDAY
BEFORE HIGH PRESSURE RIDGES FROM THE SOUTH FOR LATER IN THE WEEK.
&&
...CLIMATOLOGY...
THIS MORNING CEMENTED BOTH LITERALLY AND FIGURATIVELY ONE OF THE
COLDEST WINTER MORNINGS WE HAVE HAD IN A WHILE ACROSS THE PHI CWA.
LOCATION LOW TEMP COLDEST SINCE
PHILADELPHIA 6F 1/28/2005 LOW OF 6F
LEHIGH VLY INTL -2F 12/14/2005 LOW OF -2F
READING REGIONAL 1F 1/10/2004 LOW OF 1F
MERCER COUNTY 4F 1/29/2005 LOW OF 4F
ATLC CITY INTL 4F 3/8/2007 LOW OF 4F
NEW CASTLE CTY 5F 1/28/2005 LOW OF 1F
OTHER LOW TEMPERATURES THIS MORNING INCLUDED 17 DEGREES BELOW ZERO
IN HAINESVILLE NJ, 16 DEGREES BELLOW ZERO IN PELLETTOWN AND
MONTAGUE, NJ, 14 DEGREES BELOW ZERO IN MOUNT POCONO PA AND SUSSEX
NJ, 12 BELOW ZERO IN WALPACK NJ, 11 BELOW ZERO IN PEQUEST NJ, 10
BELOW ZERO IN BERKELEY NJ, 5 BELOW ZERO IN BASKING RIDGE NJ AND
WOODBINE NJ AS WELL AS BREINIGSVILLE PA, 4 BELOW ZERO IN PERKASIE,
PA, 1 BELOW ZERO IN MULLICA NJ, 2 DEGREES ABOVE ZERO IN DOYLESTOWN,
PA AND POTTSTOWN, PA AS WELL AS SOMERDALE, NJ, 3 DEGREES ABOVE ZERO
IN STEVENSVILLE, MD 4 DEGREES ABOVE ZERO IN GEORGETOWN DE AND 7
DEGREES ABOVE ZERO IN EASTON, MD.
WHERE DO WE GO BEYOND DAY 7 OF OUR CURRENT DETERMINISTIC FORECAST?
THERE HAS BEEN MODEL CONSISTENCY THAT THE POSITIVE PNA CROSS POLAR
FLOW PATTERN THAT MADE THIS ARCTIC BLAST POSSIBLE WILL START
COLLAPSING NEXT WEEK. THIS IS SUPPORTED BY WHERE THE CURRENT PHASE
OF THE MADDEN JULIAN OSCILLATION IS (VERY COLD FOR THE EAST) AND ITS
FORECAST EVOLUTION BY THE NUMERICAL MODELS. THE QUESTION AS TO THE
DEGREE OF THE RECOVERY THE LAST CALENDAR WEEK OF JANUARY WILL HINGE
ON WHETHER OR NOT A WEAK NAO DEVELOPS. BOTH THE GFS AND ECMWF IN
RECENT RUNS HAVE THIS FEATURE DEVELOPING WHICH WOULD PUT A LID ON
HOW MUCH OF TEMPERATURES CAN REBOUND. THEN AGAIN AFTER THE LAST
TWO MORNINGS, THE ONLY WAY WE CAN GO IS UP.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...EBERWINE
NEAR TERM...GIGI/EBERWINE
SHORT TERM...EBERWINE
LONG TERM...EBERWINE
AVIATION.../ROBERTSON
MARINE.../ROBERTSON
CLIMATOLOGY...GIGI
000
FXUS61 KPHI 171955
AFDPHI
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
255 PM EST SAT JAN 17 2009
.SYNOPSIS...
ARCTIC HIGH WILL MOVE OFFSHORE OVERNIGHT AND ALLOW BOTH CLOUDS AND
SOME LIGHT PRECIPITATION TO MOVE ALONG WITH AN APPROACHING LOW
PRESSURE. THE LOW...OVER THE GREAT LAKES WILL MOVE TO WESTERN NEW
YORK WITH A WEAKER EXTENSION OF IT JUST OFF THE DELMARVA. THE
OFFSHORE LOW WILL BECOME THE PRIMARY ONE AND THEN RACE TO NOVA
SCOTIA MONDAY AFTERNOON. THE DEPARTING LOW...AND APPROACHING HIGH
PRESSURE WILL MAINTAIN A COLD NORTHWEST FLOW WITH OCCASIONAL
FLURRIES OR LIGHT SNOW FROM TIME TO TIME INTO TUESDAY NIGHT. THE
ARCTIC COLD WILL BE REPLACED GRADUALLY WITH NEAR SEASONAL
TEMPERATURES BY MID WEEK.
&&
.NEAR TERM /THROUGH SUNDAY/...
THE CLIMATE SECTION BELOW WILL GIVE SPECIFICS ABOUT THE RECENT
COLD. WATER VAPOR SHOWING THE SHORT WAVE DIGGING SOUTHEAST FROM
MINNESOTA. CLOUDS ARE WELL EAST OF THE LOW AND INTO OUR CFA THIS
HOUR. WATER VAPOR WIND PLOT SHOWS SOME STRONG WINDS ON THE BACK
SIDE OF THE APPROACHING SHORT WAVE ON THE ORDER OF 130 KNOTS
BETWEEN 350 AND 275MB. PERHAPS THERE IS ROOM FOR THE TROUGH TO DIG
A LITTLE BEFORE MOVE EAST TOO FAST. WITHIN THE CLOUDS STEAMING IN
IS AN AREA OF SNOW THAT IS BREAKING OUT WITH THE SW JET AT 80H
THAT IS INTO WESTERN PENNSYLVANIA BACK TOWARD INDIANA. SPEEDS ARE
40 TO 55 KNOTS. THE VORT MAX AND THE STRONGEST WINDS POKE INTO
NORTHERN PENNSYLVANIA AND BRINGING SNOW INTO OUR CFA OVERNIGHT.
THE BEST UVV IS WITH THE PERPENDICULAR FLOW WITH THE THICKNESS
LINES THROUGH 06Z BEFORE BECOMING PARALLEL BY DAYBREAK SUNDAY.
JUST SOME LIGHT AMOUNTS EXPECTED ACROSS OUR REGION. WITH THE
CLOUDS ROLLING IN THE TEMPERATURES WILL LEVEL OFF AND DON`T THINK
WE`LL SEE ANY MINUS NUMBERS TONIGHT. LOWS WILL RANGE FROM 5 TO 11
DEGREES. HIGHS FOR SUNDAY 25 TO 40 DEGREES.
THERE IS A MENTION OF RAIN FOR A TIME IN THE SOUTH AND EASTERN
ZONES. HOWEVER, THE AIR IS COLD ALOFT AND IF THE INTENSITY IS
OTHER THAN LIGHT, EVAPORATIONAL COOLER COULD CHANGE THE RAIN OVER
TO SNOW BUT RIGHT NOW PLAYING IT AS A PRIMARILY RAIN EVENT EAST.
THE MODEL SOUNDINGS SUPPORT A SHALLOW LAYER OF WARM AIR WITH
SURFACE TEMPERATURES BETWEEN +2 AND +4 C. WE`LL KEEP AN EYE ON
THAT OCCURRING.
&&
.SHORT TERM /SUNDAY NIGHT THROUGH MONDAY/...
IN THE EVENING SUNDAY IF THERE IS ANY RAIN FALLING IT WILL CHANGE
BACK TO SNOW AS A SECONDARY LOW SPAWNS OVER THE WEST VIRGINIA
PANHANDLE AND MOVES OFFSHORE LATE. THIS WILL PULL COLDER AIR BACK
INTO THE CFA AND SET THE STAGE FOR MORE FRESH NORTHWEST COLD WINDS
BUT NOT AS COLD AS PAST FEW DAYS. THE BROAD UPPER TROUGH IS OVER
US AND MAINTAINING A CYCLONIC FLOW WITH OCCASIONAL SNOW FOR SUNDAY
NIGHT INTO MONDAY. FOR THE NORTHERN ZONES HAVE MENTIONED ACCUMULATIONS
OF AN INCH FOR TWO OR THREE PERIODS. NOT OUT OF THE QUESTION BUT
PERHAPS THE LONG LASTING EVENT IF DYNAMICS FAVORING A PARTICULAR
SPOT MAY YIELD A LITTLE MORE SNOW.
LOW SUNDAY NIGHT 12 TO 28. HIGHS ON MONDAY 19 TO 34. COUNTING
SEVERAL INCHES OF FRESH SNOW AND GOOD COLD AIR ADVECTION.
&&
.LONG TERM /MONDAY NIGHT THROUGH SATURDAY/...
UPPER LOW OVER EASTERN CANADA BUT LONG ARM OF THE CYCLONIC FLOW
EXTENDS BACK TOWARD THE MISSISSIPPI RIVER. SEVERAL SHORT WAVES
WILL ROTATE AROUND THE BASE OF THE TROUGH WITH THE FIRST TUESDAY
MORNING WITH SNOW AND -16C AT 80H AND THE NEXT PUSHING THROUGH ON
THURSDAY WITH MORE SNOW. WITH SUCH A COLD AIR MASS THESE ARE
NOTHING MORE THAN "GYPPED CLIPPERS" AND NOT LIKELY TO BRING MUCH
IN THE WAY OF SNOW. FOR THE FIRST TIME IN A LONG TIME...THE 80H
ZERO LINE MOVES INTO WESTERN PENNSYLVANIA BUT IS QUICKLY PUSHED
EAST AND SOUTH OF THE CFA AS ANOTHER LOW RACES ACROSS THE GREAT
LAKES INTO EASTERN NEW YORK WITH MINIMAL THREAT OF PRECIPITATION.
ALTHOUGH NO PRECIPITATION...THIS LOW WILL BE FOLLOWED BY MORE COLD
AIR. ANOTHER HIGH WILL SWEEP ACROSS THE NORTHERN PLAINS WITH THE
COLDEST AIR REMAINING IN CANADA BUT STILL THE -22C AT 80H
MAKES IT AS FAR SOUTH AS AVP-FWN LINE BY SATURDAY MORNING.
WITH THE STRONG NORTH-SOUTH TEMPERATURE GRADIENT...TEMPERATURES
WILL REMAIN BELOW NORTH FROM THE LEHIGH VALLEY AND NORTH AND CLIMB
ABOVE NORMAL THU THROUGH SATURDAY FAR SOUTHERN ZONES. WHILE WE MAY
NOT BE GETTING THE BIG SNOWS...MORE ICE AND SNOW MAY BE IN THE
WORKS OVER THE CENTRAL PLAINS BY THE 27TH.
&&
.AVIATION /19Z SATURDAY THROUGH THURSDAY/...
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY AND SURROUNDING AREAS.
ARCTIC HIGH PRESSURE MOVING OFF THE EAST COAST WILL BE FOLLOWED
TONIGHT BY LOW PRESSURE MOVING EASTWARD THROUGH THE GREAT LAKES. A
WARM FRONTAL FEATURE SEEMS TO FORM SOUTHEASTWARD INTO THE CENTRAL
MID ATLANTIC AREA, WHICH THEN LIFTS NORTHWARD THROUGH OUR AREA LATER
TONIGHT AND SUNDAY MORNING. THE NAM EVEN PRINTS OUT AN OFFSHORE
SECONDARY LOW BY 12Z, WITH THE GFS FOLLOWING WITH A WEAK LOW
EAST-NORTHEAST OF US BY 18Z SUNDAY. THESE UNIMPRESSIVE WEATHER
FEATURES SEEM TO SUGGEST THAT THE MOS GUIDANCE HAS A HANDLE ON
THINGS WITH CHANCE PROBABILITIES FOR OUR CENTRAL TAF SITES, PERHAPS
A BIT HIGHER PROBABILITIES (AND WITH LOWER CONDITIONS) FOR THE
NORTHERN TWO SITES, AND LESSER CHANCES SOUTH. SO, A TEMPO GROUP WAS
INSERTED LATE TONIGHT AND EARLY SUNDAY FOR MARGINAL VFR CONDITIONS
IN LIGHT SNOW COINCIDENT WITH THE APPROACH AND PASSAGE OF THE BEST
WARM FRONTAL LIFT. OTHERWISE, WARM ADVECTION GENERATED A RAPID
ADVECTION OF MID CLOUDS INTO THE AREA FROM THE WEST AT EARLY
AFTERNOON, AND THIS WILL BE FOLLOWED BY LOWER MIDDLE LEVEL CLOUDS
LATER THIS AFTERNOON AND THIS EVENING, AND THEN BY (MOSTLY) VFR
STRATOCUMULUS LATER TONIGHT WHICH ARE FORECAST TO CONTINUE
SUNDAY.
OUTLOOK...
THE 12Z GFS AND NAM RUNS FAILED TO DEVELOP MUCH COASTAL
FRONTOGENESIS SUNDAY NIGHT INTO MONDAY, SO VFR CONDITIONS LOOK
LIKELY FOR THOSE TIMES AS WELL, AS SUGGESTED BY MOS GUIDANCE. THEN,
A BRISK WEST TO WEST-NORTHWEST FLOW MONDAY MAY BECOME MORE NORTHWEST
MONDAY NIGHT AS LOW PRESSURE DEVELOPS ON THE OFFSHORE FRONT. HIGH
PRESSURE MAY RIDGE IN, AT LEAST TO OUR SOUTH, FOR LATER IN THE WEEK.
&&
.MARINE...
A RETURN TO A SOUTHERLY FLOW TONIGHT IS PROGGED TO BECOME MODERATE
OVERNIGHT. 925 HPA WINDS ACTUALLY INCREASE TO ABOUT 30 KNOTS, BUT
THIS ALL SHOULD NOT MIX TO THE SURFACE. WAVEWATCH DOES INDEED
FORECAST SEAS AT BUOY 44009 UP TO 5 FEET STARTING EARLY SUNDAY AND
LASTING UNTIL DARK. AT THIS TIME, SEAS ON THE OCEAN WILL BE CAPPED
AT 4 FEET, AND GUSTS AT 20 KNOTS, SO A SMALL CRAFT ADVISORY WILL NOT
BE ISSUED FOR OUR COASTAL WATERS AT THIS TIME FOR LATE TONIGHT AND
SUNDAY. HOWEVER, LATER FORECASTERS MAY NEED TO ISSUE ONE IF WINDS
AND SEAS INCREASE SLIGHTLY.
THEN, IN THE WAKE OF THE FRONT MONDAY, THE GRADIENT DOES INCREASE
FOR MONDAY INTO TUESDAY, ESPECIALLY MONDAY NIGHT WHEN THE OFFSHORE
LOW DEEPENS. AT THIS TIME, A FOURTH PERIOD SMALL CRAFT ADVISORY WILL
NOT BE ISSUED. THE GRADIENT REMAINS RATHER STRONG THROUGH WEDNESDAY
BEFORE HIGH PRESSURE RIDGES FROM THE SOUTH FOR LATER IN THE WEEK.
&&
...CLIMATOLOGY...
THIS MORNING CEMENTED BOTH LITERALLY AND FIGURATIVELY ONE OF THE
COLDEST WINTER MORNINGS WE HAVE HAD IN A WHILE ACROSS THE PHI CWA.
LOCATION LOW TEMP COLDEST SINCE
PHILADELPHIA 6F 1/28/2005 LOW OF 6F
LEHIGH VLY INTL -2F 12/14/2005 LOW OF -2F
READING REGIONAL 1F 1/10/2004 LOW OF 1F
MERCER COUNTY 4F 1/29/2005 LOW OF 4F
ATLC CITY INTL 4F 3/8/2007 LOW OF 4F
NEW CASTLE CTY 5F 1/28/2005 LOW OF 1F
OTHER LOW TEMPERATURES THIS MORNING INCLUDED 17 DEGREES BELOW ZERO
IN HAINESVILLE NJ, 16 DEGREES BELLOW ZERO IN PELLETTOWN AND
MONTAGUE, NJ, 14 DEGREES BELOW ZERO IN MOUNT POCONO PA AND SUSSEX
NJ, 12 BELOW ZERO IN WALPACK NJ, 11 BELOW ZERO IN PEQUEST NJ, 10
BELOW ZERO IN BERKELEY NJ, 5 BELOW ZERO IN BASKING RIDGE NJ AND
WOODBINE NJ AS WELL AS BREINIGSVILLE PA, 4 BELOW ZERO IN PERKASIE,
PA, 1 BELOW ZERO IN MULLICA NJ, 2 DEGREES ABOVE ZERO IN DOYLESTOWN,
PA AND POTTSTOWN, PA AS WELL AS SOMERDALE, NJ, 3 DEGREES ABOVE ZERO
IN STEVENSVILLE, MD 4 DEGREES ABOVE ZERO IN GEORGETOWN DE AND 7
DEGREES ABOVE ZERO IN EASTON, MD.
WHERE DO WE GO BEYOND DAY 7 OF OUR CURRENT DETERMINISTIC FORECAST?
THERE HAS BEEN MODEL CONSISTENCY THAT THE POSITIVE PNA CROSS POLAR
FLOW PATTERN THAT MADE THIS ARCTIC BLAST POSSIBLE WILL START
COLLAPSING NEXT WEEK. THIS IS SUPPORTED BY WHERE THE CURRENT PHASE
OF THE MADDEN JULIAN OSCILLATION IS (VERY COLD FOR THE EAST) AND ITS
FORECAST EVOLUTION BY THE NUMERICAL MODELS. THE QUESTION AS TO THE
DEGREE OF THE RECOVERY THE LAST CALENDAR WEEK OF JANUARY WILL HINGE
ON WHETHER OR NOT A WEAK NAO DEVELOPS. BOTH THE GFS AND ECMWF IN
RECENT RUNS HAVE THIS FEATURE DEVELOPING WHICH WOULD PUT A LID ON
HOW MUCH OF TEMPERATURES CAN REBOUND. THEN AGAIN AFTER THE LAST
TWO MORNINGS, THE ONLY WAY WE CAN GO IS UP.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...NONE.
NJ...NONE.
DE...NONE.
MD...NONE.
MARINE...NONE.
&&
$$
SYNOPSIS...EBERWINE
NEAR TERM...EBERWINE
SHORT TERM...EBERWINE
LONG TERM...EBERWINE
AVIATION.../
MARINE.../
CLIMATOLOGY...GIGI("OUR" FATHER OF CLIMATOLOGY)
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