000
FXUS63 KDMX 201224
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
624 AM CST TUE JAN 20 2009
.SHORT TERM...TODAY
S/WV IS EXITING IA ATTM AND WITH SUBSIDENCE IN ITS WAKE HAS LEFT A
LARGE PART OF THE ERN HLF OF THE CWA. TEMPS HAVE RESPONDED
ACCORDINGLY. NAM IS BULLISH ON HOLDING ONTO MOISTURE...BUT DO FEEL
THAT CLOUDS WILL THIN GRDLY THRU THE DAY. STRONG WAA AND SOME
SUNSHINE WILL HELP PUSH TEMPS TO NEAR 30 IN THE W AND THE LOW 20S
OVR THE E. EVEN THOUGH THE ERN ZONES WILL LKLY HAVE A LITTLE MORE
SUN...SFC RIDGE AXIS DOESN`T PASS THE AREA TIL LATE IN THE DAY WHICH
SHOULD RETARD WRMG.
.LONG TERM...TONIGHT THROUGH MONDAY
LAST FOR A BIT...IN A SEEMINGLY ENDLESS SERIES OF NORTHERN STREAM
SHORT WAVES TO EXIT THE AREA BY THIS EVENING. WEAK SFC TROUGH
BEGINNING TO FORM OVER THE PLAINS TONIGHT WHICH WILL ALLOW FOR WARM
AIR TO MOVE EAST INTO THE AREA. GFS SHOWING SOME MID LEVEL CLOUDS
FORMING AS WARM AIR ADVECTION ADVANCES EAST TONIGHT. WEAK SW FLOW
DEVELOPS AS WELL. WITH WARMING AND SNOW MELT OCCURRING OVER THE NEXT
24 TO 48 HOURS...WILL EXPECT TO SEE SOME PATCHY FOG DEVELOP. THIS
SHOULD BE ESPECIALLY TRUE OVER NORTHEAST/EAST SECTIONS OF THE
FORECAST AREA. DIFFICULT TO PLACE THE SOUTHERN EDGE OF DEVELOPMENT
BUT HAVE GENERALLY USED A ZERO-DELTA THICKNESS BAND FROM TONIGHT
THROUGH WEDNESDAY NIGHT AS A GUIDE FOR A GENERAL AREA NORTH.
PHYSICALLY THIS SHOULD BE AN AREA WHERE THE AIRMASS IS NOT WARMING
SO ANY MOISTURE INTRODUCTION WILL RESULT IN INCREASING RH AND
THUS... GREATER CHANCES FOR FOG. BOTH TONIGHT AND WED NIGHT ARE
FAVORED UNTIL THURS WHEN AIRMASS WARMS EVERYWHERE. TEMPS WILL BE
SOMEWHAT CHALLENGING FOR THE NEXT FEW DAYS AS SNOW MELT HINDERS RISE
NORTH WHILE SOUTHERN MOST REACHES WILL HAVE AN EASIER TIME REACHING
WARMER TMAX. HAVE RAISED MAX FOR WED/THURS MOST AREAS. FRONT STILL
SLOWER THAN EARLIER PROGGED SO FRI MORNING MINS WILL LIKELY BE
WARMER ...TOO. HOWEVER...FOR THE BALANCE OF FRIDAY WILL SEE STEADY
TO FALLING TEMPERATURES THROUGH EVENING. THAT COMBINED WITH
INCREASING NW SFC WINDS WILL MAKE FOR YET ANOTHER BANNER DAY. H850
TEMPS FRI NIGHT AND SAT SUPPORTIVE OF MUCH COLDER MINS AND HAVE MADE
SOME SIGNIFICANT DOWNWARD ADJUSTMENTS. GENERALLY...GFS AND EURO BOTH
SHOWING -14 TO -18C REGION WIDE BY SAT MORNING. DIFFICULTY IN RIDGE
AXIS TIMING...AND PREFER A SLIGHTLY SLOWER EURO/GEM PROG. THIS
SHOULD RESULT IN RATHER COLD TEMPS NORTHWEST SECTIONS SOUTHEAST TO
KOTM. SOME DOWNWARD ADJUSTMENTS MAY STILL BE NEEDED FOR SAT AM HOURS
BUT WILL NOT GO ANY LOWER TODAY. LITTLE TO CHEER ABOUT SATURDAY AS
COLD THICKNESSES REMAIN OVER THE REGION AND UPSTREAM WAVE BEGINS TO
SEND HIGH AND MID LEVEL CLOUDS EASTWARD. THIS SHOULD HOLD TEMPS DOWN
WITH LESS DIURNAL TREND LIKELY INTO SAT NIGHT. ONCE AGAIN DEALING
WITH TIMING ISSUES FOR THE WEEKEND SYSTEM. TYPICAL BIAS PROBLEMS
COMING INTO PLAY WITH GFS THE QUICKEST. SATURDAY NIGHT THROUGH
MONDAY WILL BE LEFT ALONE FOR NOW. UNCERTAINTY WILL RESULT IN SOME
HEADACHES FOR NEXT PACKAGE AS PLACEMENT OF OVERRUNNING SNOWS WILL
HAVE A SIGNIFICANT IMPACT ON FORECAST FOR SAT NIGHT AND SUNDAY.
CURRENTLY THE GFS/EURO NOT TOO DIFFERENT IN THIS REGARD. WITH COLD
AIRMASS IN PLACE THROUGH THE WEEKEND...SUNDAY AND MONDAY HIGHS MAY
NEED SOME DOWNWARD REVISION AS WELL. ENSEMBLE SPREAD IS RATHER LARGE
AND BODES ILL FOR CONFIDENCE. LEANING TOWARD COLDER NUMBERS FOR NOW
AND WILL PASS ALONG TO DAY SHIFT.
&&
.AVIATION...20/12Z
CLOUDS CONTINUE TO DISPT AS SUBSIDENCE TAKES OVER. EXPECT TO SEE
SOME REDEVELOPMENT WITH SNRS...BUT NOT LKLY TO ACHIEVE A BKN
CONDITION THIS AFTN. HI CLDS WL OVR SPRD THE AREA BY LATER THIS
AFTN INTO TNGT. VFR CONDS EXPECTED TO PREVAIL THIS AFTN THRU THE
NGT. THERE IS THE POSSIBILITY OF SOME LGT FOG FORMATION LATE
TNGT...BUT PROB LO ENUF ATTM I OPTED TO OMIT.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...MS JAN 09
LONG TERM...REV
AVIATION...MS JAN 09
000
FXUS63 KDMX 200856
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
256 AM CST TUE JAN 20 2009
.SHORT TERM...TODAY
S/WV IS EXITING IA ATTM AND WITH SUBSIDENCE IN ITS WAKE HAS LEFT A
LARGE PART OF THE ERN HLF OF THE CWA. TEMPS HAVE RESPONDED
ACCORDINGLY. NAM IS BULLISH ON HOLDING ONTO MOISTURE...BUT DO FEEL
THAT CLOUDS WILL THIN GRDLY THRU THE DAY. STRONG WAA AND SOME
SUNSHINE WILL HELP PUSH TEMPS TO NEAR 30 IN THE W AND THE LOW 20S
OVR THE E. EVEN THOUGH THE ERN ZONES WILL LKLY HAVE A LITTLE MORE
SUN...SFC RIDGE AXIS DOESN`T PASS THE AREA TIL LATE IN THE DAY WHICH
SHOULD RETARD WRMG.
.LONG TERM...TONIGHT THROUGH MONDAY
LAST FOR A BIT...IN A SEEMINGLY ENDLESS SERIES OF NORTHERN STREAM
SHORT WAVES TO EXIT THE AREA BY THIS EVENING. WEAK SFC TROUGH
BEGINNING TO FORM OVER THE PLAINS TONIGHT WHICH WILL ALLOW FOR WARM
AIR TO MOVE EAST INTO THE AREA. GFS SHOWING SOME MID LEVEL CLOUDS
FORMING AS WARM AIR ADVECTION ADVANCES EAST TONIGHT. WEAK SW FLOW
DEVELOPS AS WELL. WITH WARMING AND SNOW MELT OCCURRING OVER THE NEXT
24 TO 48 HOURS...WILL EXPECT TO SEE SOME PATCHY FOG DEVELOP. THIS
SHOULD BE ESPECIALLY TRUE OVER NORTHEAST/EAST SECTIONS OF THE
FORECAST AREA. DIFFICULT TO PLACE THE SOUTHERN EDGE OF DEVELOPMENT
BUT HAVE GENERALLY USED A ZERO-DELTA THICKNESS BAND FROM TONIGHT
THROUGH WEDNESDAY NIGHT AS A GUIDE FOR A GENERAL AREA NORTH.
PHYSICALLY THIS SHOULD BE AN AREA WHERE THE AIRMASS IS NOT WARMING
SO ANY MOISTURE INTRODUCTION WILL RESULT IN INCREASING RH AND
THUS... GREATER CHANCES FOR FOG. BOTH TONIGHT AND WED NIGHT ARE
FAVORED UNTIL THURS WHEN AIRMASS WARMS EVERYWHERE. TEMPS WILL BE
SOMEWHAT CHALLENGING FOR THE NEXT FEW DAYS AS SNOW MELT HINDERS RISE
NORTH WHILE SOUTHERN MOST REACHES WILL HAVE AN EASIER TIME REACHING
WARMER TMAX. HAVE RAISED MAX FOR WED/THURS MOST AREAS. FRONT STILL
SLOWER THAN EARLIER PROGGED SO FRI MORNING MINS WILL LIKELY BE
WARMER ...TOO. HOWEVER...FOR THE BALANCE OF FRIDAY WILL SEE STEADY
TO FALLING TEMPERATURES THROUGH EVENING. THAT COMBINED WITH
INCREASING NW SFC WINDS WILL MAKE FOR YET ANOTHER BANNER DAY. H850
TEMPS FRI NIGHT AND SAT SUPPORTIVE OF MUCH COLDER MINS AND HAVE MADE
SOME SIGNIFICANT DOWNWARD ADJUSTMENTS. GENERALLY...GFS AND EURO BOTH
SHOWING -14 TO -18C REGION WIDE BY SAT MORNING. DIFFICULTY IN RIDGE
AXIS TIMING...AND PREFER A SLIGHTLY SLOWER EURO/GEM PROG. THIS
SHOULD RESULT IN RATHER COLD TEMPS NORTHWEST SECTIONS SOUTHEAST TO
KOTM. SOME DOWNWARD ADJUSTMENTS MAY STILL BE NEEDED FOR SAT AM HOURS
BUT WILL NOT GO ANY LOWER TODAY. LITTLE TO CHEER ABOUT SATURDAY AS
COLD THICKNESSES REMAIN OVER THE REGION AND UPSTREAM WAVE BEGINS TO
SEND HIGH AND MID LEVEL CLOUDS EASTWARD. THIS SHOULD HOLD TEMPS DOWN
WITH LESS DIURNAL TREND LIKELY INTO SAT NIGHT. ONCE AGAIN DEALING
WITH TIMING ISSUES FOR THE WEEKEND SYSTEM. TYPICAL BIAS PROBLEMS
COMING INTO PLAY WITH GFS THE QUICKEST. SATURDAY NIGHT THROUGH
MONDAY WILL BE LEFT ALONE FOR NOW. UNCERTAINTY WILL RESULT IN SOME
HEADACHES FOR NEXT PACKAGE AS PLACEMENT OF OVERRUNNING SNOWS WILL
HAVE A SIGNIFICANT IMPACT ON FORECAST FOR SAT NIGHT AND SUNDAY.
CURRENTLY THE GFS/EURO NOT TOO DIFFERENT IN THIS REGARD. WITH COLD
AIRMASS IN PLACE THROUGH THE WEEKEND...SUNDAY AND MONDAY HIGHS MAY
NEED SOME DOWNWARD REVISION AS WELL. ENSEMBLE SPREAD IS RATHER LARGE
AND BODES ILL FOR CONFIDENCE. LEANING TOWARD COLDER NUMBERS FOR NOW
AND WILL PASS ALONG TO DAY SHIFT.
&&
.AVIATION...20/06Z
TAF FORECAST HAS BECOME LESS CONFIDENT FROM NOW THROUGH 18Z...WITH
MODEL GUIDANCE EITHER NOT IN SYNC WITH CURRENT TRENDS OR NOT MAKING
SENSE IN THE NEXT FEW HOURS BASED ON CURRENT TRENDS. HAVE OPTED TO
GO MORE OPTIMISTIC OVERALL...ESPECIALLY AT EASTERN TAFS GIVEN HIGHER
CEILINGS DEVELOPING OVERHEAD AND UPSTREAM. FLURRIES SHOULD TAPER OFF
BY 10-12Z THROUGH CENTRAL IA. EXPECTING TO HAVE VFR CONDITIONS
DEVELOP BY MID AFTERNOON AT THE LATEST...AND POSSIBLY SOONER THAN
FORECAST.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...MS JAN 09
LONG TERM...REV
AVIATION...MOYER
000
FXUS63 KDMX 200539 AAA
AFDDMX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
1140 PM CST MON JAN 19 2009
UPDATED AVIATION DISCUSSION
.SHORT TERM...TONIGHT
CONCERN FOR TONIGHT WILL BE YET ANOTHER ROUND OF FLURRIES OR LIGHT
SNOW. EXAMINATION OF 12Z SOUNDINGS SUGGESTS PRODUCTION COULD COME
FROM HIGHER RH IN DENDRITIC LAYER...AROUND H8/H9 OR 270-280K
LAYER...OR FROM SNOW SHOWERS IN STEEP LOW LEVEL LAPSE RATES. NAM
WAS ACTUALLY GENERATING SLIGHT MLCAPES THIS EVENING WRN HALF OF
FORECAST AREA. NAM/GFS 270-280K ISENT LAYERS FAVOR THIS AREA TOO
WITH SATURATION...ALTHOUGH UVM IS SPARSE AND THIS LAYER IS QUITE
STABLE. MODEL QPF CONTINUES TO GENERATE QPF HOWEVER SO WOULD NOT BE
SURPRISED TO SEE A FEW MEASURABLE AREAS MUCH LIKE PAST FEW NIGHTS SO
HAVE LOW MEASURABLE POPS ALONG WITH PERIODS OF FLURRIES.
STEEP 1000-850MB LAPSE RATES WILL ALSO ALLOW FOR GUSTY WINDS WITH
925MB WIND SUGGESTING GUSTS TO 30+KT POSSIBLE THIS EVENING. HAVE
KEPT BLOWING SNOW WORDING ACROSS DEEPER SNOW PACK. TEMP
WISE...MODELS AND GUIDANCE SEEM TO BE A BIT BEHIND THE CURVE SO HAVE
MINS NEAR MOS BLEND OR TOWARD LOWER END.
.LONG TERM...TUESDAY THROUGH MONDAY
WARMER AIR WILL GRADUALLY WORK INTO THE WEST TUESDAY AS THE
AMPLIFIED H5 TROUGH HEADS EAST. DOWNSLOPE FLOW BEHIND THE
TROUGH/WARM FRONT WILL BUMP TEMPERATURES UP EVEN MORE ON WEDNESDAY.
LEANED TOWARD THE MIDDLE OF THE SPREAD OF TEMPERATURE GUIDANCE AS
CONSIDERABLE SNOW PACK LINGERS CENTRAL AND NORTH. THE UPPER RIDGE
WILL FLATTEN THURSDAY AND THURSDAY NIGHT AS ANOTHER BOUNDARY DROPS
SOUTH THROUGH IOWA. THE COLDEST AIR WILL LAG WELL BEHIND THE
FRONT...AND THE TIMING OF THIS COLD PUSH IS SIMILAR AMONG THE
VARIOUS OPERATIONAL MODELS AND ENSEMBLES. END RESULT IS WILL STICK
WITH WARMER TEMPS SIMILAR TO PREVIOUS SHIFT. TEMPS WILL PLUNGE
THURSDAY NIGHT AND REMAIN BELOW NORMAL FRIDAY THROUGH THE WEEKEND.
THERE MAY BE SOME SCATTERED FLURRIES IN THE COLDER AIR ON
FRIDAY...BUT THE NEXT SIGNIFICANT SYSTEM SHOULD HOLD OFF UNTIL
SUNDAY AND MONDAY. THE ECMWF AND GFS/GFSENS ARE SUGGESTING A RATHER
PROLONGED PERIOD OF FRONTOGENETICAL FORCING ACROSS MAINLY THE
SOUTHERN HALF OF IOWA WHICH WOULD RESULT IN HEAVY SNOW. PLENTY CAN
CHANGE 6 TO 7 DAYS OUT...BUT SOMETHING TO WATCH.
&&
.AVIATION...20/06Z
TAF FORECAST HAS BECOME LESS CONFIDENT FROM NOW THROUGH 18Z...WITH
MODEL GUIDANCE EITHER NOT IN SYNC WITH CURRENT TRENDS OR NOT MAKING
SENSE IN THE NEXT FEW HOURS BASED ON CURRENT TRENDS. HAVE OPTED TO
GO MORE OPTIMISTIC OVERALL...ESPECIALLY AT EASTERN TAFS GIVEN HIGHER
CEILINGS DEVELOPING OVERHEAD AND UPSTREAM. FLURRIES SHOULD TAPER OFF
BY 10-12Z THROUGH CENTRAL IA. EXPECTING TO HAVE VFR CONDITIONS
DEVELOP BY MID AFTERNOON AT THE LATEST...AND POSSIBLY SOONER THAN
FORECAST.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...BSS
LONG TERM...KINNEY
AVIATION...MOYER
000
FXUS63 KDMX 192329 AAA
AFDDMX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
528 PM CST MON JAN 19 2009
UPDATED AVIATION DISCUSSION
.SHORT TERM...TONIGHT
CONCERN FOR TONIGHT WILL BE YET ANOTHER ROUND OF FLURRIES OR LIGHT
SNOW. EXAMINATION OF 12Z SOUNDINGS SUGGESTS PRODUCTION COULD COME
FROM HIGHER RH IN DENDRITIC LAYER...AROUND H8/H9 OR 270-280K
LAYER...OR FROM SNOW SHOWERS IN STEEP LOW LEVEL LAPSE RATES. NAM
WAS ACTUALLY GENERATING SLIGHT MLCAPES THIS EVENING WRN HALF OF
FORECAST AREA. NAM/GFS 270-280K ISENT LAYERS FAVOR THIS AREA TOO
WITH SATURATION...ALTHOUGH UVM IS SPARSE AND THIS LAYER IS QUITE
STABLE. MODEL QPF CONTINUES TO GENERATE QPF HOWEVER SO WOULD NOT BE
SURPRISED TO SEE A FEW MEASURABLE AREAS MUCH LIKE PAST FEW NIGHTS SO
HAVE LOW MEASURABLE POPS ALONG WITH PERIODS OF FLURRIES.
STEEP 1000-850MB LAPSE RATES WILL ALSO ALLOW FOR GUSTY WINDS WITH
925MB WIND SUGGESTING GUSTS TO 30+KT POSSIBLE THIS EVENING. HAVE
KEPT BLOWING SNOW WORDING ACROSS DEEPER SNOW PACK. TEMP
WISE...MODELS AND GUIDANCE SEEM TO BE A BIT BEHIND THE CURVE SO HAVE
MINS NEAR MOS BLEND OR TOWARD LOWER END.
.LONG TERM...TUESDAY THROUGH MONDAY
WARMER AIR WILL GRADUALLY WORK INTO THE WEST TUESDAY AS THE
AMPLIFIED H5 TROUGH HEADS EAST. DOWNSLOPE FLOW BEHIND THE
TROUGH/WARM FRONT WILL BUMP TEMPERATURES UP EVEN MORE ON WEDNESDAY.
LEANED TOWARD THE MIDDLE OF THE SPREAD OF TEMPERATURE GUIDANCE AS
CONSIDERABLE SNOW PACK LINGERS CENTRAL AND NORTH. THE UPPER RIDGE
WILL FLATTEN THURSDAY AND THURSDAY NIGHT AS ANOTHER BOUNDARY DROPS
SOUTH THROUGH IOWA. THE COLDEST AIR WILL LAG WELL BEHIND THE
FRONT...AND THE TIMING OF THIS COLD PUSH IS SIMILAR AMONG THE
VARIOUS OPERATIONAL MODELS AND ENSEMBLES. END RESULT IS WILL STICK
WITH WARMER TEMPS SIMILAR TO PREVIOUS SHIFT. TEMPS WILL PLUNGE
THURSDAY NIGHT AND REMAIN BELOW NORMAL FRIDAY THROUGH THE WEEKEND.
THERE MAY BE SOME SCATTERED FLURRIES IN THE COLDER AIR ON
FRIDAY...BUT THE NEXT SIGNIFICANT SYSTEM SHOULD HOLD OFF UNTIL
SUNDAY AND MONDAY. THE ECMWF AND GFS/GFSENS ARE SUGGESTING A RATHER
PROLONGED PERIOD OF FRONTOGENETICAL FORCING ACROSS MAINLY THE
SOUTHERN HALF OF IOWA WHICH WOULD RESULT IN HEAVY SNOW. PLENTY CAN
CHANGE 6 TO 7 DAYS OUT...BUT SOMETHING TO WATCH.
&&
.AVIATION...20/00Z
WILL HAVE HIGH LEVELS OF MOISTURE HANGING AROUND BELOW 5000 FT
THROUGH THE TAF PERIOD. THRU 12 TO 18Z...THE HIGHEST RH LEVELS ARE
IN A LAYER OF SUB -10C AIR...BUT LIFT IS WEAK TO NEUTRAL.
THEREFORE...PERIODS OF LIGHT SNOWFALL/SNOW SHOWERS/FLURRIES WILL
PERSIST...REDUCING VSBY AT TIMES TO 1 1/2 MILES AT THE WORST...BUT
MOST LIKELY IN THE 3 TO 5 MILE RANGE. TAFS WILL ONLY GO AS LOW AS
THE MORE CONFIDENT 3 MILES. CEILINGS WILL LIKELY REMAIN OR BE
LOWERING UNDER 010 BY AROUND 12Z...THEN LIFT BACK TO MVFR RANGE AFT
18Z.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...BSS
LONG TERM...KINNEY
AVIATION...MOYER
000
FXUS63 KDMX 192127
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
327 PM CST MON JAN 19 2009
.SHORT TERM...TONIGHT
CONCERN FOR TONIGHT WILL BE YET ANOTHER ROUND OF FLURRIES OR LIGHT
SNOW. EXAMINATION OF 12Z SOUNDINGS SUGGESTS PRODUCTION COULD COME
FROM HIGHER RH IN DENDRITIC LAYER...AROUND H8/H9 OR 270-280K
LAYER...OR FROM SNOW SHOWERS IN STEEP LOW LEVEL LAPSE RATES. NAM
WAS ACTUALLY GENERATING SLIGHT MLCAPES THIS EVENING WRN HALF OF
FORECAST AREA. NAM/GFS 270-280K ISENT LAYERS FAVOR THIS AREA TOO
WITH SATURATION...ALTHOUGH UVM IS SPARSE AND THIS LAYER IS QUITE
STABLE. MODEL QPF CONTINUES TO GENERATE QPF HOWEVER SO WOULD NOT BE
SURPRISED TO SEE A FEW MEASURABLE AREAS MUCH LIKE PAST FEW NIGHTS SO
HAVE LOW MEASURABLE POPS ALONG WITH PERIODS OF FLURRIES.
STEEP 1000-850MB LAPSE RATES WILL ALSO ALLOW FOR GUSTY WINDS WITH
925MB WIND SUGGESTING GUSTS TO 30+KT POSSIBLE THIS EVENING. HAVE
KEPT BLOWING SNOW WORDING ACROSS DEEPER SNOW PACK. TEMP
WISE...MODELS AND GUIDANCE SEEM TO BE A BIT BEHIND THE CURVE SO HAVE
MINS NEAR MOS BLEND OR TOWARD LOWER END.
.LONG TERM...TUESDAY THROUGH MONDAY
WARMER AIR WILL GRADUALLY WORK INTO THE WEST TUESDAY AS THE
AMPLIFIED H5 TROUGH HEADS EAST. DOWNSLOPE FLOW BEHIND THE
TROUGH/WARM FRONT WILL BUMP TEMPERATURES UP EVEN MORE ON WEDNESDAY.
LEANED TOWARD THE MIDDLE OF THE SPREAD OF TEMPERATURE GUIDANCE AS
CONSIDERABLE SNOW PACK LINGERS CENTRAL AND NORTH. THE UPPER RIDGE
WILL FLATTEN THURSDAY AND THURSDAY NIGHT AS ANOTHER BOUNDARY DROPS
SOUTH THROUGH IOWA. THE COLDEST AIR WILL LAG WELL BEHIND THE
FRONT...AND THE TIMING OF THIS COLD PUSH IS SIMILAR AMONG THE
VARIOUS OPERATIONAL MODELS AND ENSEMBLES. END RESULT IS WILL STICK
WITH WARMER TEMPS SIMILAR TO PREVIOUS SHIFT. TEMPS WILL PLUNGE
THURSDAY NIGHT AND REMAIN BELOW NORMAL FRIDAY THROUGH THE WEEKEND.
THERE MAY BE SOME SCATTERED FLURRIES IN THE COLDER AIR ON
FRIDAY...BUT THE NEXT SIGNIFICANT SYSTEM SHOULD HOLD OFF UNTIL
SUNDAY AND MONDAY. THE ECMWF AND GFS/GFSENS ARE SUGGESTING A RATHER
PROLONGED PERIOD OF FRONTOGENETICAL FORCING ACROSS MAINLY THE
SOUTHERN HALF OF IOWA WHICH WOULD RESULT IN HEAVY SNOW. PLENTY CAN
CHANGE 6 TO 7 DAYS OUT...BUT SOMETHING TO WATCH.
&&
.AVIATION...19/18Z
PRIMARY QUESTION WILL BE SNOW AND LOW CLOUD TRENDS. MULTIPLE
STRATUS LAYERS IN PLACE UPSTREAM INTO MN WHICH WILL RESULT IN
EXTENDED PERIOD OF AT LEAST MVFR CIGS TONIGHT AND INTO EARLY TUE.
ALTHOUGH NOT PREVALENT ENOUGH TO TRY AND TIME OR MENTION IN THE
FORECAST IFR CIGS ARE POSSIBLE AS WELL...WHICH WAS ONE REASON WHY
MVFR CIGS BELOW 2KFT WERE NOTED.
OCCASIONAL LIGHT SNOW SHOWERS ARE EXPECTED FOR PROLONGED PERIOD AS
WELL. MUCH LIKE CIGS...SHOULD BE MAINLY MVFR ALTHOUGH BRIEFLY IFR
VSBYS CANNOT BE RULED OUT.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/AVIATION...BSS
LONG TERM...KINNEY
000
FXUS63 KDMX 191811
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1211 PM CST MON JAN 19 2009
.UPDATE...
LITTLE CHANGE TO GOING FORECAST FOR MORNING UPDATE. PERIOD OF LIGHT
SNOW OR FLURRIES STILL SEEMS ON TRACK WITH PROLONGED DENDRITIC LAYER
SATURATION...BUT WITH LITTLE UVM. -12 TO -18C LAYER(S) DEEPER THAN
PREVIOUS EVENTS PER LOOK AT SOUNDINGS. ADDITION OF 18Z TAF
DISCUSSION AS WELL.
&&
.DISCUSSION...
CLIPPER TRACKING ACROSS SOUTHERN IL EARLY TODAY WITH COLD FRONT
MOVING WEST INTO EASTERN NEBRASKA. AREAS OF FLURRIES CONTINUE OVER
IOWA BUT STRATUS ON THE WANE...ESPECIALLY NORTH. WILL LOOK FOR A
PERIOD OF SUN EARLY TODAY BEFORE CLOUDS ROLL BACK AND DEVELOP INTO
THE AREA BY NOON. NEXT UPSTREAM WAVE OVER SOUTHWEST ONTARIO PROVINCE
SIMILAR TO SUNDAYS. AS IT DROPS SOUTH INTO THE UPPER GREAT LAKES
AND CENTRAL PLAINS...IT WILL ARRIVE WITH FLURRIES AND LIGHT SNOW BY
EARLY AFTERNOON...CONTINUING INTO THE EVENING HOURS. TEMPS TO BE
COOLER TODAY MOST SECTIONS AS RADIATIONAL COOLING NOW WILL HOLD BACK
HIGHS LATER TODAY. MOISTURE AGAIN LIMITED AS SOURCE REGION OVER
CENTRAL CANADA. A FEW HUNDREDTHS POSSIBLE WHICH WITH SNOW WATER
RATIOS OF 10:15:1 WILL RESULT IN AREAS OF ONE TENTH TO ONE HALF INCH
SNOWFALL OVER THE FORECAST AREA BY THIS EVENING. WINDS TO PICK UP A
BIT LATER THIS EVENING...BUT DAYTIME CONDITIONS LOOK BENIGN. IF ANY
ROAD ISSUES COME TO PASS...MOST CHALLENGES EXPECTED TO REMAIN ACROSS
NORTH AND EAST FOR NOW. S/WV SETTING OFF THE SNOW THIS AFTN IS
VERIFYING FARTHER E AND A LTL FASTER THAN PROGGED. FOR THAT
REASON...FEEL WINDS WILL BE HIER THAN PROGGED THIS EVE OVR THE NWRN
HLF OF THE CWA. FOR THAT REASON...INTRODUCED AREAS OF BLWG SNW FOR
THE EVE HRS IN AREAS WHERE DEEPER EXISTING SNW CVR REMAINS. NEXT
PROB WILL BE WITH THE WRM UP THRU MID WEEK. SLOW DOWN EXPECTED YDA
BASED ON GEM/ECMWF IS NOW ADVTZD IN THE GFS AND WILL KEEP WITH THE
THINKING OF THU BEING THE WRMST DAY OF THE WEEK. H8 TEMPS I THE +5
TO +10 RANGE ON ALL MDLS...HWVR MXG WILL BE A PROB. OVR SNW COVER
DON`T EXPECT TO SEE TEMPS GET OUT OF THE 30S...BUT IS SHUD DEF WRM
UP. CDFNT MOVS THRU THU NGT OR FRI AND IT LOOKS LIKE A QUICK SHOT
OF COLDER AIR BFR DISCONTINUOUS RETROGRESSION IN THE UPR PTRN BEGINS
TO TURN THINGS MORE ACTIVE HEADING INTO WEEK 2 WITH SLOW EVOLUTION
OF -PNA TYPE PTRN.
&&
.AVIATION...19/18Z
PRIMARY QUESTION WILL BE SNOW AND LOW CLOUD TRENDS. MULTIPLE
STRATUS LAYERS IN PLACE UPSTREAM INTO MN WHICH WILL RESULT IN
EXTENDED PERIOD OF AT LEAST MVFR CIGS TONIGHT AND INTO EARLY TUE.
ALTHOUGH NOT PREVALENT ENOUGH TO TRY AND TIME OR MENTION IN THE
FORECAST IFR CIGS ARE POSSIBLE AS WELL...WHICH WAS ONE REASON WHY
MVFR CIGS BELOW 2KFT WERE NOTED.
OCCASIONAL LIGHT SNOW SHOWERS ARE EXPECTED FOR PROLONGED PERIOD AS
WELL. MUCH LIKE CIGS...SHOULD BE MAINLY MVFR ALTHOUGH BRIEFLY IFR
VSBYS CANNOT BE RULED OUT.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/AVIATION...REV/BSS
LONG TERM...MS JAN 09
000
FXUS63 KDMX 191130 AAA
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
530 AM CST MON JAN 19 2009
.UPDATED AVIATION DISCUSSION.
.DISCUSSION...
CLIPPER TRACKING ACROSS SOUTHERN IL EARLY TODAY WITH COLD FRONT
MOVING WEST INTO EASTERN NEBRASKA. AREAS OF FLURRIES CONTINUE OVER
IOWA BUT STRATUS ON THE WANE...ESPECIALLY NORTH. WILL LOOK FOR A
PERIOD OF SUN EARLY TODAY BEFORE CLOUDS ROLL BACK AND DEVELOP INTO
THE AREA BY NOON. NEXT UPSTREAM WAVE OVER SOUTHWEST ONTARIO PROVINCE
SIMILAR TO SUNDAYS. AS IT DROPS SOUTH INTO THE UPPER GREAT LAKES
AND CENTRAL PLAINS...IT WILL ARRIVE WITH FLURRIES AND LIGHT SNOW BY
EARLY AFTERNOON...CONTINUING INTO THE EVENING HOURS. TEMPS TO BE
COOLER TODAY MOST SECTIONS AS RADIATIONAL COOLING NOW WILL HOLD BACK
HIGHS LATER TODAY. MOISTURE AGAIN LIMITED AS SOURCE REGION OVER
CENTRAL CANADA. A FEW HUNDREDTHS POSSIBLE WHICH WITH SNOW WATER
RATIOS OF 10:15:1 WILL RESULT IN AREAS OF ONE TENTH TO ONE HALF INCH
SNOWFALL OVER THE FORECAST AREA BY THIS EVENING. WINDS TO PICK UP A
BIT LATER THIS EVENING...BUT DAYTIME CONDITIONS LOOK BENIGN. IF ANY
ROAD ISSUES COME TO PASS...MOST CHALLENGES EXPECTED TO REMAIN ACROSS
NORTH AND EAST FOR NOW. S/WV SETTING OFF THE SNOW THIS AFTN IS
VERIFYING FARTHER E AND A LTL FASTER THAN PROGGED. FOR THAT
REASON...FEEL WINDS WILL BE HIER THAN PROGGED THIS EVE OVR THE NWRN
HLF OF THE CWA. FOR THAT REASON...INTRODUCED AREAS OF BLWG SNW FOR
THE EVE HRS IN AREAS WHERE DEEPER EXISTING SNW CVR REMAINS. NEXT
PROB WILL BE WITH THE WRM UP THRU MID WEEK. SLOW DOWN EXPECTED YDA
BASED ON GEM/ECMWF IS NOW ADVTZD IN THE GFS AND WILL KEEP WITH THE
THINKING OF THU BEING THE WRMST DAY OF THE WEEK. H8 TEMPS I THE +5
TO +10 RANGE ON ALL MDLS...HWVR MXG WILL BE A PROB. OVR SNW COVER
DON`T EXPECT TO SEE TEMPS GET OUT OF THE 30S...BUT IS SHUD DEF WRM
UP. CDFNT MOVS THRU THU NGT OR FRI AND IT LOOKS LIKE A QUICK SHOT
OF COLDER AIR BFR DISCONTINUOUS RETROGRESSION IN THE UPR PTRN BEGINS
TO TURN THINGS MORE ACTIVE HEADING INTO WEEK 2 WITH SLOW EVOLUTION
OF -PNA TYPE PTRN.
&&
.AVIATION...19/12Z
WEAK BUBBLE HIGH OVER THE AREA EARLY TODAY WITH VFR CONDITIONS
EXPECTED. WATER VAPOR IMAGERY ALREADY SHOWING PRONOUNCED UPPER LEVEL
WAVE DROPPING SOUTH FROM SOUTHERN CANADA INTO NORTHERN MN. CLOUDS
WILL RETURN THIS AFTERNOON WITH GENERAL MVFR CIGS APPROACHING BY
NOON NORTH AND MID TO LATE AFTERNOON ELSEWHERE. LATEST RUNS OF
MODELS HAVE TAKEN BEST LIFT EAST OF AREA THIS AFTERNOON/EVENING.
HAVE MODIFIED TIMING OF PREVIOUS PACKAGE AS SLOWER ARRIVAL EXPECTED.
HAVE ALSO TRIMMED BACK ON SNOW SHOWERS WEST WITH BETTER CHANCES OF
MORE SIGNIFICANT CONDITIONS AT KALO...KMCW...AND KOTM. CLOUDS WILL
STICK AROUND THROUGH THE EVENING AS THE SYSTEM ROTATES EAST. CIGS
SHOULD REMAIN MVFR AS WINDS PICK UP IN THE WAKE OF THE LOW. /REV
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...REV
LONG TERM...MS JAN 09
AVIATION...REV
000
FXUS63 KDMX 190936 AAB
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
330 AM CST MON JAN 19 2009
.DISCUSSION...
CLIPPER TRACKING ACROSS SOUTHERN IL EARLY TODAY WITH COLD FRONT
MOVING WEST INTO EASTERN NEBRASKA. AREAS OF FLURRIES CONTINUE OVER
IOWA BUT STRATUS ON THE WANE...ESPECIALLY NORTH. WILL LOOK FOR A
PERIOD OF SUN EARLY TODAY BEFORE CLOUDS ROLL BACK AND DEVELOP INTO
THE AREA BY NOON. NEXT UPSTREAM WAVE OVER SOUTHWEST ONTARIO PROVINCE
SIMILAR TO SUNDAYS. AS IT DROPS SOUTH INTO THE UPPER GREAT LAKES
AND CENTRAL PLAINS...IT WILL ARRIVE WITH FLURRIES AND LIGHT SNOW BY
EARLY AFTERNOON...CONTINUING INTO THE EVENING HOURS. TEMPS TO BE
COOLER TODAY MOST SECTIONS AS RADIATIONAL COOLING NOW WILL HOLD BACK
HIGHS LATER TODAY. MOISTURE AGAIN LIMITED AS SOURCE REGION OVER
CENTRAL CANADA. A FEW HUNDREDTHS POSSIBLE WHICH WITH SNOW WATER
RATIOS OF 10:15:1 WILL RESULT IN AREAS OF ONE TENTH TO ONE HALF INCH
SNOWFALL OVER THE FORECAST AREA BY THIS EVENING. WINDS TO PICK UP A
BIT LATER THIS EVENING...BUT DAYTIME CONDITIONS LOOK BENIGN. IF ANY
ROAD ISSUES COME TO PASS...MOST CHALLENGES EXPECTED TO REMAIN ACROSS
NORTH AND EAST FOR NOW. S/WV SETTING OFF THE SNOW THIS AFTN IS
VERIFYING FARTHER E AND A LTL FASTER THAN PROGGED. FOR THAT
REASON...FEEL WINDS WILL BE HIER THAN PROGGED THIS EVE OVR THE NWRN
HLF OF THE CWA. FOR THAT REASON...INTRODUCED AREAS OF BLWG SNW FOR
THE EVE HRS IN AREAS WHERE DEEPER EXISTING SNW CVR REMAINS. NEXT
PROB WILL BE WITH THE WRM UP THRU MID WEEK. SLOW DOWN EXPECTED YDA
BASED ON GEM/ECMWF IS NOW ADVTZD IN THE GFS AND WILL KEEP WITH THE
THINKING OF THU BEING THE WRMST DAY OF THE WEEK. H8 TEMPS I THE +5
TO +10 RANGE ON ALL MDLS...HWVR MXG WILL BE A PROB. OVR SNW COVER
DON`T EXPECT TO SEE TEMPS GET OUT OF THE 30S...BUT IS SHUD DEF WRM
UP. CDFNT MOVS THRU THU NGT OR FRI AND IT LOOKS LIKE A QUICK SHOT
OF COLDER AIR BFR DISCONTINUOUS RETROGRESSION IN THE UPR PTRN BEGINS
TO TURN THINGS MORE ACTIVE HEADING INTO WEEK 2 WITH SLOW EVOLUTION
OF -PNA TYPE PTRN.
&&
.AVIATION...19/06Z
A SUBTLE SURFACE TROUGH IS MOVING FROM NORTH TO SOUTH ACROSS THE
STATE...CURRENTLY STRETCHING FROM NEAR KOTM TO JUST SOUTH OF KDSM.
BEHIND THIS TROUGH WINDS ARE COMING AROUND TO 020-040 AND BECOMING
GUSTY FOR AN HOUR OR TWO...THEN GRADUALLY DIMINISHING AND TURNING
BACK TO 340-360. THE STRATUS DECK THAT HAS BLANKETED THE AREA ALL
AFTERNOON AND EVENING IS FINALLY SHOWING SIGNS OF BREAKING UP...WITH
THE CLEARING LINE NEARING THE MN/IA BORDER AND JUST SOME PATCHES OF
LOW CLOUDS AFTER THAT. PREVAILING MVFR CIGS WILL THUS END SOON AT
THE NORTHERN SITES AND WITHIN A FEW HOURS AT THE SOUTHERN
SITES...ALONG WITH LIGHT SNOW ENDING SOON AT KOTM AND KDSM.
THEREAFTER QUIET VFR CONDITIONS ARE EXPECTED AT LEAST THROUGH
SUNRISE WITH INTERMITTENT CEILINGS BETWEEN FL050 AND FL120.
ANOTHER WEAK TROUGH APPROACHING THE AREA MONDAY MORNING WILL BRING
REWEWED MVFR CIGS AND SNOW...WHICH WILL BE HEAVIEST AT KMCW AND KALO
FROM ABOUT MIDDAY THROUGH THE AFTERNOON. MVFR TO IFR VSBYS WILL
OCCUR AT THESE TERMINALS. AT THE OTHER THREE MVFR VSBYS AND CIGS ARE
LESS CERTAIN AND WOULD LIKELY BE INTERMITTENT DURING THE AFTERNOON
IF THEY OCCUR.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...REV
LONG TERM...MS JAN 09
AVIATION...REV
000
FXUS63 KDMX 190523 AAB
AFDDMX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
1123 PM CST SUN JAN 18 2009
...UPDATED AVIATION DISCUSSION...
.SHORT TERM...TONIGHT
MAIN PROBLEM REMAINS EXTENT OF FLURRIES AND LIGHT SNOW TONIGHT.
RADAR TRENDS CONTINUE TO INDICATE FLURRIES MOVING DOWN MS RIVER
VALLEY...BUT WITH APPARENTLY TRAJECTORIES THAT WILL ONLY BRUSH NERN
SECTIONS AT BEST. MODEL DENDRITIC RH DOES NOT SUGGEST MUCH FOR
FORECAST AREA EITHER SO WILL GO DRY AFTER MIDNIGHT WITH ONLY
ISOLATED LIGHT SNOW SHOWER WORDING NE TIL CHANCES INCREASE AGAIN MON.
TEMPS SOMEWHAT QUESTIONABLE AS WELL WHICH DEPEND ON BOTH DECOUPLING
AND CLOUD TRENDS...WHICH ARE SOMEWHAT INTERCHANGEABLE. THERE ARE
SOME CLEAR PATCHES UPSTREAM SO EXPECT SOME DECOUPLING AND COOLING
POTENTIAL WHICH CURRENT FORECAST SEEMS TO HAVE IN HAND.
.LONG TERM...MONDAY THRU SUNDAY
HIGHLY AMPLIFIED UPPER FLOW WILL CONTINUE MONDAY AND ANOTHER DECENT
SHORT WAVE WILL DROP SOUTH THROUGH THE REGION ALONG WITH A WEAK
SURFACE BOUNDARY. QG FORCING WILL MOVE INTO NORTHERN IOWA DURING THE
MORNING THEN SOUTHWARD THROUGH THE DAY. THE BEST LIFT AND MOISTURE
WILL BE LOCATED ACROSS NORTHEAST PORTIONS OF THE FORECAST AREA. HPC
QPF UP TO A FEW HUNDREDTHS LOOKS REASONABLE AND COBB OUTPUT
INDICATES SNOW TO LIQUID RATIOS OF 20:1 OR HIGHER...YIELDING MAX
AMOUNTS APPROACHING AN INCH. FORCING WILL WANE QUICKLY MONDAY
EVENING WITH ONLY LINGERING FLURRIES EXPECTED. SOMEWHAT COLDER AIR
WILL BE IN PLACE ACROSS THE FORECAST AREA ON MONDAY...BUT THE
WARMING TREND IS STILL ON TARGET FOR TUESDAY AND WEDNESDAY AS THE
UPPER RIDGE FINALLY HEADS EAST. THERE ARE TIMING DIFFERENCES WITH
THE ARRIVAL OF ANOTHER WEAK FRONT THURSDAY. THE OPERATIONAL GFS IS
FASTER...THE GEM/GFSENS/UKMET SLOWEST...AND THE ECMWF THE FASTEST.
SENSIBLE WEATHER WILL BE MINIMAL WITH THE FROPA...SO THE MAIN IMPACT
WILL BE HIGHS ON THURSDAY AND WITH THE UNCERTAINTY WILL STICK CLOSE
TO HPC GUIDANCE. ALL MODELS AGREE IN BRINGING IN COLDER AIR LATE
THURSDAY THROUGH THE WEEKEND. THE NEXT SIGNIFICANT SYSTEM WILL HOLD
OFF UNTIL LATE SUNDAY INTO MONDAY.
&&
.AVIATION...19/06Z
A SUBTLE SURFACE TROUGH IS MOVING FROM NORTH TO SOUTH ACROSS THE
STATE...CURRENTLY STRETCHING FROM NEAR KOTM TO JUST SOUTH OF KDSM.
BEHIND THIS TROUGH WINDS ARE COMING AROUND TO 020-040 AND BECOMING
GUSTY FOR AN HOUR OR TWO...THEN GRADUALLY DIMINISHING AND TURNING
BACK TO 340-360. THE STRATUS DECK THAT HAS BLANKETED THE AREA ALL
AFTERNOON AND EVENING IS FINALLY SHOWING SIGNS OF BREAKING UP...WITH
THE CLEARING LINE NEARING THE MN/IA BORDER AND JUST SOME PATCHES OF
LOW CLOUDS AFTER THAT. PREVAILING MVFR CIGS WILL THUS END SOON AT
THE NORTHERN SITES AND WITHIN A FEW HOURS AT THE SOUTHERN
SITES...ALONG WITH LIGHT SNOW ENDING SOON AT KOTM AND KDSM.
THEREAFTER QUIET VFR CONDITIONS ARE EXPECTED AT LEAST THROUGH
SUNRISE WITH INTERMITTENT CEILINGS BETWEEN FL050 AND FL120.
ANOTHER WEAK TROUGH APPROACHING THE AREA MONDAY MORNING WILL BRING
REWEWED MVFR CIGS AND SNOW...WHICH WILL BE HEAVIEST AT KMCW AND KALO
FROM ABOUT MIDDAY THROUGH THE AFTERNOON. MVFR TO IFR VSBYS WILL
OCCUR AT THESE TERMINALS. AT THE OTHER THREE MVFR VSBYS AND CIGS ARE
LESS CERTAIN AND WOULD LIKELY BE INTERMITTENT DURING THE AFTERNOON
IF THEY OCCUR.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...BSS
LONG TERM...KINNEY
AVIATION...LEE
000
FXUS63 KDMX 182335 AAA
AFDDMX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
535 PM CST SUN JAN 18 2009
...UPDATED AVIATION DISCUSSION...
.SHORT TERM...TONIGHT
MAIN PROBLEM REMAINS EXTENT OF FLURRIES AND LIGHT SNOW TONIGHT.
RADAR TRENDS CONTINUE TO INDICATE FLURRIES MOVING DOWN MS RIVER
VALLEY...BUT WITH APPARENTLY TRAJECTORIES THAT WILL ONLY BRUSH NERN
SECTIONS AT BEST. MODEL DENDRITIC RH DOES NOT SUGGEST MUCH FOR
FORECAST AREA EITHER SO WILL GO DRY AFTER MIDNIGHT WITH ONLY
ISOLATED LIGHT SNOW SHOWER WORDING NE TIL CHANCES INCREASE AGAIN MON.
TEMPS SOMEWHAT QUESTIONABLE AS WELL WHICH DEPEND ON BOTH DECOUPLING
AND CLOUD TRENDS...WHICH ARE SOMEWHAT INTERCHANGEABLE. THERE ARE
SOME CLEAR PATCHES UPSTREAM SO EXPECT SOME DECOUPLING AND COOLING
POTENTIAL WHICH CURRENT FORECAST SEEMS TO HAVE IN HAND.
.LONG TERM...MONDAY THRU SUNDAY
HIGHLY AMPLIFIED UPPER FLOW WILL CONTINUE MONDAY AND ANOTHER DECENT
SHORT WAVE WILL DROP SOUTH THROUGH THE REGION ALONG WITH A WEAK
SURFACE BOUNDARY. QG FORCING WILL MOVE INTO NORTHERN IOWA DURING THE
MORNING THEN SOUTHWARD THROUGH THE DAY. THE BEST LIFT AND MOISTURE
WILL BE LOCATED ACROSS NORTHEAST PORTIONS OF THE FORECAST AREA. HPC
QPF UP TO A FEW HUNDREDTHS LOOKS REASONABLE AND COBB OUTPUT
INDICATES SNOW TO LIQUID RATIOS OF 20:1 OR HIGHER...YIELDING MAX
AMOUNTS APPROACHING AN INCH. FORCING WILL WANE QUICKLY MONDAY
EVENING WITH ONLY LINGERING FLURRIES EXPECTED. SOMEWHAT COLDER AIR
WILL BE IN PLACE ACROSS THE FORECAST AREA ON MONDAY...BUT THE
WARMING TREND IS STILL ON TARGET FOR TUESDAY AND WEDNESDAY AS THE
UPPER RIDGE FINALLY HEADS EAST. THERE ARE TIMING DIFFERENCES WITH
THE ARRIVAL OF ANOTHER WEAK FRONT THURSDAY. THE OPERATIONAL GFS IS
FASTER...THE GEM/GFSENS/UKMET SLOWEST...AND THE ECMWF THE FASTEST.
SENSIBLE WEATHER WILL BE MINIMAL WITH THE FROPA...SO THE MAIN IMPACT
WILL BE HIGHS ON THURSDAY AND WITH THE UNCERTAINTY WILL STICK CLOSE
TO HPC GUIDANCE. ALL MODELS AGREE IN BRINGING IN COLDER AIR LATE
THURSDAY THROUGH THE WEEKEND. THE NEXT SIGNIFICANT SYSTEM WILL HOLD
OFF UNTIL LATE SUNDAY INTO MONDAY.
&&
.AVIATION...19/00Z
STRATUS DECK CONTINUES TO PRODUCE PREVAILING MVFR CIGS ACROSS MOST
OF THE AREAS...WITH SOME TERMINALS POPPING IN AND OUT OF VFR. WITH
LITTLE CHANGE IN LARGE SCALE PATTERNS OVERNIGHT EXPECT MORE OF THE
SAME...WITH CIGS BECOMING LOW VFR /BASES AROUND FL035-040/ OVERNIGHT
THEN GOING BACK DOWN TO MVFR ON MONDAY MORNING. LIGHT SNOW SHOWERS
WILL PRODUCE MVFR AND BRIEFLY IFR VSBYS AT KMCW AND KALO DURING THE
NEXT FEW HOURS...WITH LIGHTER FLURRIES EXPECTED ACROSS THE AREA
LATER TONIGHT INTO TOMORROW BUT MOSTLY PRODUCING LITTLE VSBY
RESTRICTION.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...BSS
LONG TERM...KINNEY
AVIATION...LEE
000
FXUS63 KDMX 182114
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
314 PM CST SUN JAN 18 2009
.SHORT TERM...TONIGHT
MAIN PROBLEM REMAINS EXTENT OF FLURRIES AND LIGHT SNOW TONIGHT.
RADAR TRENDS CONTINUE TO INDICATE FLURRIES MOVING DOWN MS RIVER
VALLEY...BUT WITH APPARENTLY TRAJECTORIES THAT WILL ONLY BRUSH NERN
SECTIONS AT BEST. MODEL DENDRITIC RH DOES NOT SUGGEST MUCH FOR
FORECAST AREA EITHER SO WILL GO DRY AFTER MIDNIGHT WITH ONLY
ISOLATED LIGHT SNOW SHOWER WORDING NE TIL CHANCES INCREASE AGAIN MON.
TEMPS SOMEWHAT QUESTIONABLE AS WELL WHICH DEPEND ON BOTH DECOUPLING
AND CLOUD TRENDS...WHICH ARE SOMEWHAT INTERCHANGEABLE. THERE ARE
SOME CLEAR PATCHES UPSTREAM SO EXPECT SOME DECOUPLING AND COOLING
POTENTIAL WHICH CURRENT FORECAST SEEMS TO HAVE IN HAND.
.LONG TERM...MONDAY THRU SUNDAY
HIGHLY AMPLIFIED UPPER FLOW WILL CONTINUE MONDAY AND ANOTHER DECENT
SHORT WAVE WILL DROP SOUTH THROUGH THE REGION ALONG WITH A WEAK
SURFACE BOUNDARY. QG FORCING WILL MOVE INTO NORTHERN IOWA DURING THE
MORNING THEN SOUTHWARD THROUGH THE DAY. THE BEST LIFT AND MOISTURE
WILL BE LOCATED ACROSS NORTHEAST PORTIONS OF THE FORECAST AREA. HPC
QPF UP TO A FEW HUNDREDTHS LOOKS REASONABLE AND COBB OUTPUT
INDICATES SNOW TO LIQUID RATIOS OF 20:1 OR HIGHER...YIELDING MAX
AMOUNTS APPROACHING AN INCH. FORCING WILL WANE QUICKLY MONDAY
EVENING WITH ONLY LINGERING FLURRIES EXPECTED. SOMEWHAT COLDER AIR
WILL BE IN PLACE ACROSS THE FORECAST AREA ON MONDAY...BUT THE
WARMING TREND IS STILL ON TARGET FOR TUESDAY AND WEDNESDAY AS THE
UPPER RIDGE FINALLY HEADS EAST. THERE ARE TIMING DIFFERENCES WITH
THE ARRIVAL OF ANOTHER WEAK FRONT THURSDAY. THE OPERATIONAL GFS IS
FASTER...THE GEM/GFSENS/UKMET SLOWEST...AND THE ECMWF THE FASTEST.
SENSIBLE WEATHER WILL BE MINIMAL WITH THE FROPA...SO THE MAIN IMPACT
WILL BE HIGHS ON THURSDAY AND WITH THE UNCERTAINTY WILL STICK CLOSE
TO HPC GUIDANCE. ALL MODELS AGREE IN BRINGING IN COLDER AIR LATE
THURSDAY THROUGH THE WEEKEND. THE NEXT SIGNIFICANT SYSTEM WILL HOLD
OFF UNTIL LATE SUNDAY INTO MONDAY.
&&
.AVIATION...18/18Z
LOW CLOUDS TO CONTINUE TO ROTATION AROUND BACK EDGE OF DEPARTING
GREAT LAKES LOW...HEADING SOUTHWARD INTO IA. WRN
SITES...FOD/DSM...ARE ON THE BACK EDGE OF VFR STRATUS AND WILL GO IN
AND OUT OF CLOUDS BUT PREDOMINATE TREND SHOULD BE TOWARD CIGS.
MCW/ALO/OTM WILL MAINLY BE AFFECTED BY MVFR CIGS THROUGHOUT THE
PERIOD...ALTHOUGH THERE MAY BE VFR PERIODS AS WELL AS IFR FOR A FEW
HOURS THIS AFTERNOON. OCCASIONAL LIGHT SNOW SHOWERS OR FLURRIES
WILL BE POSSIBLE THROUGHOUT THE PERIOD EAST. IMPOSSIBLE TO
TIME...BUT FEEL IT WILL BE MORE IN THAN OUT SO INCLUDED IN BODY OF
FORECAST FOR PROLONGED PERIOD.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/AVIATION...BSS
LONG TERM...KINNEY
000
FXUS63 KDMX 181801
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1201 PM CST SUN JAN 18 2009
.DISCUSSION...
ANOTHER UPPER LEVEL WAVE TO DROP SOUTH ACROSS THE REGION THIS
AFTERNOON INCREASING THE POSSIBILITY OF SNOW SHOWERS. LARGE GRADIENT
CONTINUES OVER THE AREA EARLY ON WITH LOWER TO MID 20S ACROSS THE
NORTHEAST AND UPPER 20S TO LOWER 30S CENTRAL AND WEST. EXPECTING
HIGHS TO WARM A BIT WEST TODAY WITH SUPPORT FOR MODERATE SNOW
SHOWERS EAST AS LAPSE RATES BECOME UNSTABLE DURING THE AFTERNOON
HOURS. WIND FIELDS MAY MIX TO 15 TO 25 MPH AT TIMES NORTHEAST AND
EAST WHICH MAY RESULT IN SOME MINOR BLOWING SNOW ISSUES. LOOKS LIKE
THIS WILL BE MORE TEMPORARY IN NATURE THAN SATURDAY WHEN GRADIENT
WINDS PROPELLED SNOW ACROSS ROADS FOR MUCH OF EARLY AFTERNOON AND TO
EVENING OVER PORTIONS OF EASTERN AND SMALL PART OF CENTRAL IOWA.
WINDS SHOULD SUBSIDE BY LATE AFTERNOON AS INSTABILITY LESSENS. WILL
CONTINUE WITH OCNL FLRYS GOING INTO TONIGHT IN THE EAST AS FIRST
S/WV EXITS. THEN FOR MON...EXPECT A DECENT ROUND OF FLRYS GIVEN
SHALLOW MSTR AND RATHER STG W/WV MOVG THRU. ENDED IT MON EVE AS
THINGS PULL EAST. FOR THE MOST PART THE CWA WILL BE DOMINATED BY
THE CHINOOK REGIME AND TMPS WILL BE ABV NORMAL THRU AT LEAST THU BFR
ANY COOLING SETS IN. SHOULD SEE A DROP BY THE WKND TO TEMPS A LTL
BLO NORMAL AS THE NEXT POLAR HI PRES SETTLES SWD INTO THE N CNTRL
U.S.
&&
.AVIATION...18/18Z
LOW CLOUDS TO CONTINUE TO ROTATION AROUND BACK EDGE OF DEPARTING
GREAT LAKES LOW...HEADING SOUTHWARD INTO IA. WRN
SITES...FOD/DSM...ARE ON THE BACK EDGE OF VFR STRATUS AND WILL GO IN
AND OUT OF CLOUDS BUT PREDOMINATE TREND SHOULD BE TOWARD CIGS.
MCW/ALO/OTM WILL MAINLY BE AFFECTED BY MVFR CIGS THROUGHOUT THE
PERIOD...ALTHOUGH THERE MAY BE VFR PERIODS AS WELL AS IFR FOR A FEW
HOURS THIS AFTERNOON. OCCASIONAL LIGHT SNOW SHOWERS OR FLURRIES
WILL BE POSSIBLE THROUGHOUT THE PERIOD EAST. IMPOSSIBLE TO
TIME...BUT FEEL IT WILL BE MORE IN THAN OUT SO INCLUDED IN BODY OF
FORECAST FOR PROLONGED PERIOD.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/AVIATION...REV/BSS
LONG TERM...MS JAN 09
000
FXUS63 KDMX 181138 AAB
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
328 AM CST SUN JAN 18 2009
.DISCUSSION...
ANOTHER UPPER LEVEL WAVE TO DROP SOUTH ACROSS THE REGION THIS
AFTERNOON INCREASING THE POSSIBILITY OF SNOW SHOWERS. LARGE GRADIENT
CONTINUES OVER THE AREA EARLY ON WITH LOWER TO MID 20S ACROSS THE
NORTHEAST AND UPPER 20S TO LOWER 30S CENTRAL AND WEST. EXPECTING
HIGHS TO WARM A BIT WEST TODAY WITH SUPPORT FOR MODERATE SNOW
SHOWERS EAST AS LAPSE RATES BECOME UNSTABLE DURING THE AFTERNOON
HOURS. WIND FIELDS MAY MIX TO 15 TO 25 MPH AT TIMES NORTHEAST AND
EAST WHICH MAY RESULT IN SOME MINOR BLOWING SNOW ISSUES. LOOKS LIKE
THIS WILL BE MORE TEMPORARY IN NATURE THAN SATURDAY WHEN GRADIENT
WINDS PROPELLED SNOW ACROSS ROADS FOR MUCH OF EARLY AFTERNOON AND TO
EVENING OVER PORTIONS OF EASTERN AND SMALL PART OF CENTRAL IOWA.
WINDS SHOULD SUBSIDE BY LATE AFTERNOON AS INSTABILITY LESSENS. WILL
CONTINUE WITH OCNL FLRYS GOING INTO TONIGHT IN THE EAST AS FIRST
S/WV EXITS. THEN FOR MON...EXPECT A DECENT ROUND OF FLRYS GIVEN
SHALLOW MSTR AND RATHER STG W/WV MOVG THRU. ENDED IT MON EVE AS
THINGS PULL EAST. FOR THE MOST PART THE CWA WILL BE DOMINATED BY
THE CHINOOK REGIME AND TMPS WILL BE ABV NORMAL THRU AT LEAST THU BFR
ANY COOLING SETS IN. SHOULD SEE A DROP BY THE WKND TO TEMPS A LTL
BLO NORMAL AS THE NEXT POLAR HI PRES SETTLES SWD INTO THE N CNTRL
U.S.
&&
.AVIATION...18/12Z
A LAYER OF STRATUS CONTINUES OVER MUCH OF CENTRAL IA. CIGS REMAIN
GENERALLY MVFR WITH SOME IFR FROM TIME TO TIME. ANOTHER WAVE SHOULD
PASS ACROSS THE AREA THIS AFTERNOON WITH SNOW SHOWERS. EXPECT MAX
INSTABILITY BETWEEN 19-23Z WITH SOME POSSIBLE VIGOROUS SHOWERS
NORTHEAST. LOWERED VSBYS TO 3-5SM NORTH AND EAST. LOOK FOR QUIETER
WX BY EVENING AND OVERNIGHT TONIGHT. WINDS TO MIX FOR A WHILE TODAY
AND THEN DIMINISH BY 00Z. WINDS MAY CAUSE MINOR ISSUES WITH GROUND
BLOWING SNOW...BUT HAVE NOT MENTIONED IT. /REV
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...REV
LONG TERM...MS JAN 09
AVIATION...REV
000
FXUS63 KDMX 180928 AAB
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
328 AM CST SUN JAN 18 2009
.DISCUSSION...
ANOTHER UPPER LEVEL WAVE TO DROP SOUTH ACROSS THE REGION THIS
AFTERNOON INCREASING THE POSSIBILITY OF SNOW SHOWERS. LARGE GRADIENT
CONTINUES OVER THE AREA EARLY ON WITH LOWER TO MID 20S ACROSS THE
NORTHEAST AND UPPER 20S TO LOWER 30S CENTRAL AND WEST. EXPECTING
HIGHS TO WARM A BIT WEST TODAY WITH SUPPORT FOR MODERATE SNOW
SHOWERS EAST AS LAPSE RATES BECOME UNSTABLE DURING THE AFTERNOON
HOURS. WIND FIELDS MAY MIX TO 15 TO 25 MPH AT TIMES NORTHEAST AND
EAST WHICH MAY RESULT IN SOME MINOR BLOWING SNOW ISSUES. LOOKS LIKE
THIS WILL BE MORE TEMPORARY IN NATURE THAN SATURDAY WHEN GRADIENT
WINDS PROPELLED SNOW ACROSS ROADS FOR MUCH OF EARLY AFTERNOON AND TO
EVENING OVER PORTIONS OF EASTERN AND SMALL PART OF CENTRAL IOWA.
WINDS SHOULD SUBSIDE BY LATE AFTERNOON AS INSTABILITY LESSENS. WILL
CONTINUE WITH OCNL FLRYS GOING INTO TONIGHT IN THE EAST AS FIRST
S/WV EXITS. THEN FOR MON...EXPECT A DECENT ROUND OF FLRYS GIVEN
SHALLOW MSTR AND RATHER STG W/WV MOVG THRU. ENDED IT MON EVE AS
THINGS PULL EAST. FOR THE MOST PART THE CWA WILL BE DOMINATED BY
THE CHINOOK REGIME AND TMPS WILL BE ABV NORMAL THRU AT LEAST THU BFR
ANY COOLING SETS IN. SHOULD SEE A DROP BY THE WKND TO TEMPS A LTL
BLO NORMAL AS THE NEXT POLAR HI PRES SETTLES SWD INTO THE N CNTRL
U.S.
&&
.AVIATION...18/06Z
STRATUS DECK CONTINUES TO PRODUCE FLURRIES AND PREVAILING MVFR CIGS
ACROSS THE AREA. SLIGHTLY HEAVIER SNOW IN WESTERN IOWA MAY PRODUCE
BRIEF PERIODS OF MVFR VSBYS AT KFOD AND KDSM WITHIN THE NEXT SEVERAL
HOURS. OTHERWISE NO VSBY RESTRICTIONS ANTICIPATED. CIG HEIGHTS WILL
RISE A BIT AFTER SUNRISE...WITH INTERMITTENT VFR CIGS POSSIBLE
DURING THE DAY SUNDAY. WINDS WILL ALSO BE LIGHTER ON
SUNDAY...GENERALLY AROUND 10 KT BUT A BIT HIGHER WITH SOME GUSTS AT
KMCW.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...REV
LONG TERM...MS JAN 09
AVIATION...LEE
000
FXUS63 KDMX 180530 AAB
AFDDMX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
1130 PM CST SAT JAN 17 2009
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
STRONG NORTHWEST WINDS CONTINUE THIS AFTERNOON WITH OCCASIONAL GUSTS
OVER 50 MPH. THIS HAS RESULTED IN SHALLOW DRIFTING SNOW AND AREAS OF
LOW VISIBILITY IN OPEN AREAS. THE GFS IS MODELING THE DEVELOPING
AREA OF SNOW IN EASTERN NORTH DAKOTA AND IS INDICATING DECENT
MOISTURE IN THE DENDRITIC ZONE. THE GFS BRINGS LIGHT QPF SOUTH INTO
IOWA TONIGHT. HAVE INCREASED POPS...ESPECIALLY NORTHEAST THIS
EVENING. ACCUMULATIONS WILL BE LIGHT...BUT WEATHER WILL BE
COMPOUNDED BY CONTINUED STRONG GUSTS INTO THIS EVENING AND HAVE
CONTINUED MENTION OF BLOWING SNOW OVER THE NORTH HALF. FAVORED
WARMER END OF GUIDANCE WITH ENTRENCHED LOW LEVEL CLOUD SHIELD.
THE MAIN FORECAST ISSUES ARE CHANCES FOR LIGHT SNOW OVER THE NEXT
FEW DAYS AND TEMPERATURES. SHORT RANGE MODELS ARE IN AGREEMENT IN
DIGGING MORE SHORT WAVE ENERGY SOUTH INTO THE STATE SUNDAY. HAVE
INTRODUCED CHANCE POPS ACROSS THE EAST AND EXPANDED MENTION OF
FLURRIES TO THE EAST. FORCING IS NOT IMPRESSIVE AT ALL...BUT A
SATURATED LAYER THROUGH 700MB...ALL IN THE FAVORABLE DENDRITIC
GROWTH ZONE...WILL BE IN PLACE OVER THE EAST...WITH LESSOR MOISTURE
TO THE WEST. MODEL QPF IS MEAGER...BUT DENDRITE PRODUCTION WILL
LIKELY RESULT IN SOME MINOR ACCUMULATIONS...MAINLY EAST. A FEW
FLURRIES WILL LIKELY LINGER INTO SUNDAY NIGHT. ANOTHER SHORT WAVE
WILL IMPACT THE FORECAST AREA ON MONDAY. HAVE INTRODUCED ONLY
FLURRIES FOR NOW...BUT WOULD NOT BE SURPRISED TO SEE SOME MORE MINOR
ACCUMULATIONS. SUNDAY WILL BE THE COLDEST DAY THROUGH MIDWEEK AS
COLD OR NEUTRAL ADVECTION CONTINUES IN THE SHARPLY AMPLIFIED
NORTHERLY FLOW...AND STAYED NEAR THE COLDER END OF GUIDANCE. EXPECT
A WARMING TREND MONDAY THROUGH WEDNESDAY AS THE UPPER RIDGE
GRADUALLY BUILDS IN FROM THE WEST. A CLIPPER WILL DROP SOUTH
THURSDAY WITH LITTLE MOISTURE BUT ANOTHER SHOT OF COLDER AIR BY LATE
WEEK. HAVE KEPT DRY FORECAST FROM TUESDAY THROUGH SATURDAY.
&&
.AVIATION...18/06Z
STRATUS DECK CONTINUES TO PRODUCE FLURRIES AND PREVAILING MVFR CIGS
ACROSS THE AREA. SLIGHTLY HEAVIER SNOW IN WESTERN IOWA MAY PRODUCE
BRIEF PERIODS OF MVFR VSBYS AT KFOD AND KDSM WITHIN THE NEXT SEVERAL
HOURS. OTHERWISE NO VSBY RESTRICTIONS ANTICIPATED. CIG HEIGHTS WILL
RISE A BIT AFTER SUNRISE...WITH INTERMITTENT VFR CIGS POSSIBLE
DURING THE DAY SUNDAY. WINDS WILL ALSO BE LIGHTER ON
SUNDAY...GENERALLY AROUND 10 KT BUT A BIT HIGHER WITH SOME GUSTS AT
KMCW.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...BSS
LONG TERM...KINNEY
AVIATION...LEE
000
FXUS63 KDMX 172339 AAA
AFDDMX
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DES MOINES IA
539 PM CST SAT JAN 17 2009
...UPDATED AVIATION DISCUSSION...
.DISCUSSION...
STRONG NORTHWEST WINDS CONTINUE THIS AFTERNOON WITH OCCASIONAL GUSTS
OVER 50 MPH. THIS HAS RESULTED IN SHALLOW DRIFTING SNOW AND AREAS OF
LOW VISIBILITY IN OPEN AREAS. THE GFS IS MODELING THE DEVELOPING
AREA OF SNOW IN EASTERN NORTH DAKOTA AND IS INDICATING DECENT
MOISTURE IN THE DENDRITIC ZONE. THE GFS BRINGS LIGHT QPF SOUTH INTO
IOWA TONIGHT. HAVE INCREASED POPS...ESPECIALLY NORTHEAST THIS
EVENING. ACCUMULATIONS WILL BE LIGHT...BUT WEATHER WILL BE
COMPOUNDED BY CONTINUED STRONG GUSTS INTO THIS EVENING AND HAVE
CONTINUED MENTION OF BLOWING SNOW OVER THE NORTH HALF. FAVORED
WARMER END OF GUIDANCE WITH ENTRENCHED LOW LEVEL CLOUD SHIELD.
THE MAIN FORECAST ISSUES ARE CHANCES FOR LIGHT SNOW OVER THE NEXT
FEW DAYS AND TEMPERATURES. SHORT RANGE MODELS ARE IN AGREEMENT IN
DIGGING MORE SHORT WAVE ENERGY SOUTH INTO THE STATE SUNDAY. HAVE
INTRODUCED CHANCE POPS ACROSS THE EAST AND EXPANDED MENTION OF
FLURRIES TO THE EAST. FORCING IS NOT IMPRESSIVE AT ALL...BUT A
SATURATED LAYER THROUGH 700MB...ALL IN THE FAVORABLE DENDRITIC
GROWTH ZONE...WILL BE IN PLACE OVER THE EAST...WITH LESSOR MOISTURE
TO THE WEST. MODEL QPF IS MEAGER...BUT DENDRITE PRODUCTION WILL
LIKELY RESULT IN SOME MINOR ACCUMULATIONS...MAINLY EAST. A FEW
FLURRIES WILL LIKELY LINGER INTO SUNDAY NIGHT. ANOTHER SHORT WAVE
WILL IMPACT THE FORECAST AREA ON MONDAY. HAVE INTRODUCED ONLY
FLURRIES FOR NOW...BUT WOULD NOT BE SURPRISED TO SEE SOME MORE MINOR
ACCUMULATIONS. SUNDAY WILL BE THE COLDEST DAY THROUGH MIDWEEK AS
COLD OR NEUTRAL ADVECTION CONTINUES IN THE SHARPLY AMPLIFIED
NORTHERLY FLOW...AND STAYED NEAR THE COLDER END OF GUIDANCE. EXPECT
A WARMING TREND MONDAY THROUGH WEDNESDAY AS THE UPPER RIDGE
GRADUALLY BUILDS IN FROM THE WEST. A CLIPPER WILL DROP SOUTH
THURSDAY WITH LITTLE MOISTURE BUT ANOTHER SHOT OF COLDER AIR BY LATE
WEEK. HAVE KEPT DRY FORECAST FROM TUESDAY THROUGH SATURDAY.
&&
.AVIATION...18/00Z
WITH SURFACE LOW OVER GREAT LAKES AND SHORTWAVES PASSING THROUGH
NORTHERLY FLOW ALOFT...STRATUS DECK WILL PERSIST OVER THE AREA
THROUGH TOMORROW. THIS WILL RESULT IN PREVAILING MVFR CEILINGS
THROUGH VIRTUALLY THE ENTIRE TAF PERIOD AT ALL TERMINALS. WIND
SPEEDS WILL GRADUALLY DIMINISH OVER THE NEXT COUPLE OF HOURS AND
BECOME SIGNIFICANTLY LIGHTER BY 03Z...WHICH WILL ALSO REDUCE BLOWING
SNOW WHICH HAS BEEN AFFECTING PRIMARILY KMCW AND KALO. REGIONAL
RADAR COMPOSITES AND SURFACE OBS SHOW AREAS OF LIGHT SNOW MOVING
INTO NORTHEASTERN IA ASSOCIATED WITH A SHORTWAVE...AND THESE WILL
PRODUCE INTERMITTENT MVFR OR POSSIBLY LOWER VSBYS AT KMCW AND KALO
FOR THE NEXT SEVERAL HOURS. ONCE THE SNOW MOVES BY AND WINDS LIGHTEN
UP...THE AVIATION FORECAST WILL BE FAIRLY UNEVENTFUL THROUGH THE TAF
PERIOD EXCEPT FOR THE PREVAILING LOW CIGS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...BSS
LONG TERM...KINNEY
AVIATION...LEE
000
FXUS63 KDMX 172131
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
330 PM CST SAT JAN 17 2009
.DISCUSSION...
STRONG NORTHWEST WINDS CONTINUE THIS AFTERNOON WITH OCCASIONAL GUSTS
OVER 50 MPH. THIS HAS RESULTED IN SHALLOW DRIFTING SNOW AND AREAS OF
LOW VISIBILITY IN OPEN AREAS. THE GFS IS MODELING THE DEVELOPING
AREA OF SNOW IN EASTERN NORTH DAKOTA AND IS INDICATING DECENT
MOISTURE IN THE DENDRITIC ZONE. THE GFS BRINGS LIGHT QPF SOUTH INTO
IOWA TONIGHT. HAVE INCREASED POPS...ESPECIALLY NORTHEAST THIS
EVENING. ACCUMULATIONS WILL BE LIGHT...BUT WEATHER WILL BE
COMPOUNDED BY CONTINUED STRONG GUSTS INTO THIS EVENING AND HAVE
CONTINUED MENTION OF BLOWING SNOW OVER THE NORTH HALF. FAVORED
WARMER END OF GUIDANCE WITH ENTRENCHED LOW LEVEL CLOUD SHIELD.
THE MAIN FORECAST ISSUES ARE CHANCES FOR LIGHT SNOW OVER THE NEXT
FEW DAYS AND TEMPERATURES. SHORT RANGE MODELS ARE IN AGREEMENT IN
DIGGING MORE SHORT WAVE ENERGY SOUTH INTO THE STATE SUNDAY. HAVE
INTRODUCED CHANCE POPS ACROSS THE EAST AND EXPANDED MENTION OF
FLURRIES TO THE EAST. FORCING IS NOT IMPRESSIVE AT ALL...BUT A
SATURATED LAYER THROUGH 700MB...ALL IN THE FAVORABLE DENDRITIC
GROWTH ZONE...WILL BE IN PLACE OVER THE EAST...WITH LESSOR MOISTURE
TO THE WEST. MODEL QPF IS MEAGER...BUT DENDRITE PRODUCTION WILL
LIKELY RESULT IN SOME MINOR ACCUMULATIONS...MAINLY EAST. A FEW
FLURRIES WILL LIKELY LINGER INTO SUNDAY NIGHT. ANOTHER SHORT WAVE
WILL IMPACT THE FORECAST AREA ON MONDAY. HAVE INTRODUCED ONLY
FLURRIES FOR NOW...BUT WOULD NOT BE SURPRISED TO SEE SOME MORE MINOR
ACCUMULATIONS. SUNDAY WILL BE THE COLDEST DAY THROUGH MIDWEEK AS
COLD OR NEUTRAL ADVECTION CONTINUES IN THE SHARPLY AMPLIFIED
NORTHERLY FLOW...AND STAYED NEAR THE COLDER END OF GUIDANCE. EXPECT
A WARMING TREND MONDAY THROUGH WEDNESDAY AS THE UPPER RIDGE
GRADUALLY BUILDS IN FROM THE WEST. A CLIPPER WILL DROP SOUTH
THURSDAY WITH LITTLE MOISTURE BUT ANOTHER SHOT OF COLDER AIR BY LATE
WEEK. HAVE KEPT DRY FORECAST FROM TUESDAY THROUGH SATURDAY.
&&
.AVIATION...17/18Z
OVERALL LITTLE CHANGE ANTICIPATED THROUGH THE PERIOD WITH PERSISTENT
MVFR CONDITIONS...MAINLY SUB 2KFT CIGS. THERE IS SOME POTENTIAL TO
GO ABOVE 2000KT OR JUST INTO IFR...BUT TIMING AND CONFIDENCE NOT
GREAT ENOUGH TO TRY AND PIN DOWN AT THIS POINT. MVFR BLOWING SNOW
MAY AFFECT MCW/ALO...ESPECIALLY MCW...UNTIL WINDS SUBSIDE THIS
EVENING. INTERMITTENT FLURRIES WILL BE POSSIBLE AS WELL...MAINLY
NERN SECTIONS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/AVIATION...BSS
LONG TERM...KINNEY
000
FXUS63 KDMX 171821
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1221 PM CST SAT JAN 17 2009
.DISCUSSION...
DECENT CHINOOK FNT MOVG INTO NWRN IA THIS MRNG AND SHUD BRING TEMPS
UP SHARPLY THIS MRNG...THEN SHOW LITTLE RISE THIS AFTN. SOME FLRYS
AND PTCHY FZDZ IN THE WAKE OF THE FNT WITH LTL ICE IN SOUNDING THRU
THE DENDRITIC LYR UNTIL TNGT WHEN DEEPER MSTR ROTATES IN WITH THE
CYC CRCLN. WENT WITH SCT TO OCNL FLRYS FOR TNGT AND SUN WITH MSTR
AND S/WV AND DID NOT BRING TEMPS UP A LOT WITH THE CAA TAKING
PLACE. REST OF THE WEEK LOOKS MAINLY DRY WITH WRMG TEMPS THRU MID
WEEK AS CHINOOK PTRN DOMINATES THRU MUCH OF THE WEEK. TRANSITION
BEGINS TWD THE WKND AND SIG MOD DIF TDA BTWN THE GFS AND THE ECMWF.
THE EC IS TRENDING MORE TWD A -PNA TYPE PTRN...WHILE THE GFS DOES
NOT. ATTM WOULD LEAN MORE TWD THE EC SOLNS...HWVR THAT IS BYND THIS
FCST PD.
&&
.AVIATION...17/18Z
OVERALL LITTLE CHANGE ANTICIPATED THROUGH THE PERIOD WITH PERSISTENT
MVFR CONDITIONS...MAINLY SUB 2KFT CIGS. THERE IS SOME POTENTIAL TO
GO ABOVE 2000KT OR JUST INTO IFR...BUT TIMING AND CONFIDENCE NOT
GREAT ENOUGH TO TRY AND PIN DOWN AT THIS POINT. MVFR BLOWING SNOW
MAY AFFECT MCW/ALO...ESPECIALLY MCW...UNTIL WINDS SUBSIDE THIS
EVENING. INTERMITTENT FLURRIES WILL BE POSSIBLE AS WELL...MAINLY
NERN SECTIONS.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM/AVIATION...CC/BSS
LONG TERM...MS JAN 09
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