863
FXUS61 KLWX 090854
AFDLWX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
354 AM EST TUE FEB 9 2010
SYNOPSIS
LOW PRESSURE OVER THE GULF STATES WILL MOVE OFF THE CAROLINA COAST
TONIGHT AND INTENSIFY OFF THE DELMARVA OVERNIGHT. THIS WILL PROVIDE
ANOTHER ROUND OF WINTRY PRECIPITATION TO THE MID ATLANTIC REGION
TODAY THROUGH WEDNESDAY. HIGH PRESSURE RETURNS LATE IN THE WEEK.
NEAR TERM /TODAY/
IT'S BEEN AN INTENSE NGT...IN ADDITION TO THE WX WE'VE HAD TO DEAL
W/ A SHUTDOWN OF THE COOLING SYSTEM WHERE OUR COMPUTERS ARE HOUSED.
GNRL GIST OF THE FCST RMNS UNCHGD - ANOTHER ROUND OF WINTER WX AS
LOW PRES DVLPG OVR THE LOWER GULF STATES INTENSIFIES E OF ORF
TNGT. LGT SNOW ALREADY ON RDR ABT 50 MILES S OF NELSON/AUGUSTA
COUNTIES WL BE MOVG INTO THE SRN SXN OF OUR CWA AFTR 4
AM...REACHING THE DC BELTWAY ARND 9 AM. SNOWFALL SHOULD BE ON LGT
SIDE TDA. TENMPS THIS AFTN SHOULD BE AT OR STLY BLO FRZG ACROSS
THE CWA.
SHORT TERM /TONIGHT THROUGH WEDNESDAY NGT/
TNGT THAT LOW WL MOVE E OF ORF AND BEGIN TO INTENSIFY. SNOWFALL
RATES WL BEGIN TO INCRS AS WELL ACRS THE MAJORITY OF THE CWA. BY
WED MRNG TOTALS RANGING FM ARND 6 INCHES IN THE HIGHLANDS TO 8-9
INCHES IN THE DC-BALT CORRIDOR ARE LKLY. THE COUNTIES THAT WERE
PRVSLY IN A WTCH - ST. MARY'S TO SPOTSY...HV BEEN UPGRADED TO A
WRNG. ST. MARY'S WAS TOUGH TO FCST FOR - BLV ARND PAX RVR BY WED
MRNG 2-3" PSBL WHILE IN THE NW PART OF THE COUNTY 7" IN LKLY.
LOW TEMPS IN THE HIGHLANDS U TEENS. RMNDR OF CWA IN THE 20S.
WED-WED NGT...
LITTLE CHANGE TO WED IN THE GRIDS OTHER THAN MAKING SOME TIMING
ADJUSTMENTS TO THE EXIT OF THE LOW PRESSURE SYSTEM AND SFC WINDS.
PERIODS OF HEAVY SNOW AND GUSTY WINDS EXPECTED AS THE COASTAL LOW
DEEPENS AND MOVES PARALLEL TO THE DELMARVA COAST ON WED AFTN. AS
THEY HAVE FOR THE PAST SEVERAL DAYS...MOST OF THE AVAILABLE GUIDANCE
CONTINUES TO PAINT A REGIONAL AREA OF PRECIP THAT QUICKLY DEVELOPS
OVER THE ERN HALF OF THE CWA ON WED MORNING...REACHING ITS PEAK
INTENSITY BY EARLY AFTN /CENTERED OVER THE MD CHESAPEAKE/ AND
EVENTUALLY ROTATING OFF THE COAST BY LATE AFTN-EARLY EVENING.
MAKING THE SITUATION MORE COMPLEX AND THE SYSTEM EVEN STRONGER IS A
SCENARIO WELL-DEPICTED ON THE LATEST NAM WITH TWO VERY DEEP SFC LOWS
ROTATING OFF THE MID ATLC COAST. THE DEEPER ONE SLIDES ABOUT THE
SERN SIDE OF THE ONE CLOSER TO THE COAST. BY MIDDAY WED...BOTH ARE
NEARING 985 MB...BY EARLY EVENING ALMOST ANOTHER 10MB DROP IN EACH
/AN EVEN BIGGER DROP FOR THE ONE JUST OFF THE SRN COAST OF CAPE
COD/. BOTH WILL EVENTUALLY BE WRAPPED BECOME VERTICALLY STACKED AS
THE UPPER LOW SWINGS OFF THE COAST BY LATE AFTN WED. THIS WILL
INCREASE THE INTENSITY OF PRECIP BANDS STREWN ACROSS THE ERN
SEABOARD OF THE MID ATLC /PARTICULARLY THE I-95 CORRIDOR OF NRN VA
AND ERN MD...THRU NJ AND LONG ISLAND.
IN THE ZONES...GUSTS OF 35-40 MPH APPEAR FOR THE WED-WED NIGHT
PERIOD WHICH IS COINCIDENT W/ HIGH SNOW CHANCES...BUT IN TERMS OF
TIMING AND PROGRESSION...THE STRONGEST WINDS WILL BE WRAPPED AROUND
THE BACKSIDE OF THE PRECIP W/ THE DRIER AIR THAT CUT-OFF THE PRECIP
ON THE WRN EDGE OF THE SNOW BANDS. SO EVEN THOUGH BREEZY CONDITIONS
/GUSTS 15-30 MPH/ WILL BE COMMON AS THE LAST FEW SNOW BANDS SET-UP
ACROSS THE REGION WED MORNING-AFTN...THE +35MPH GUSTS /ON LAND
AREAS/ EXPECTED TO MOSTLY APPEAR AFTER A BULK OF THE SNOW BANDS
HAVE DISSIPATED AND MOVED EAST.
THE STRONG NW FLOW WILL CONTINUE INTO THE LATE NIGHT HRS...W/ A FEW
BANDS OF LIGHT SNOW CONTINUING TO STREAM DOWN THE NERN PORTIONS OF
MD AND ADJACENT NRN VA BUT LITTLE ACCUMULATION EXPECTED FROM THIS
ACTIVITY. UPSLOPE SNOW FOR THE MTNS WILL CONTINUE INTO MIDDAY THU
AND MORE BREEZY NW FLOW FOR THE REST OF THE AREA.
LONG TERM /THURSDAY THROUGH MONDAY/
AFTER THE TUE-WED SNOW STORM...LITTLE ON THE HORIZON IN TERMS OF
WX-MAKERS...JUST A DAILY ROUTINE OF NW WINDS...TEMPS BARELY PEAKING
OUT OF FREEZING DURING THE DAYTIME HRS...DROPPING BACK WELL-BELOW
FREEZING OVERNIGHT. THIS REGIME IS FROM REINFORCING UPPER WAVES OF
CANADIAN AIR THAT SLIDE DOWN THE GREAT LAKES FROM S CNTRL
CANADA...AND ROTATE AROUND A RESIDENT UPPER LOW STATIONED OVER NEW
FOUNDLAND. ONE OF THESE UPPER VORT WILL PUSH DOWN THE NRN PLAINS
EARLY NEXT WEEK /LIKE THIS INCOMING STORM SYSTEM/ BUT WON/T HAVE THE
SUPPORT OF GULF MOISTURE AND THEREFORE LOOKS TO BE LITTLE MORE THAN
A DISORGANIZED BATCH OF PRECIP AS IT MOVES THRU SUN NIGHT INTO MON.
THO IT DOES MEAN MORE UPSLOPE SNOW FOR THE CNTRL APLCNS FOR
CONSECUTIVE DAYS.
AVIATION /TODAY THROUGH SATURDAY/
VFR CONDS THIS MRNG WL BEGIN TO DEGRADE 1ST AT CHO. THE MAJOR
AIRPORTS WL MOVE INTO IFR REALM ATER NOON...AND DEGRADE TO LIFR
TONGT IN MDT SNOW...BCMG HVY TOWARDS WED MRNG.
BANDS OF HEAVY SNOW POSSIBLE WED MORNING AND MID AFTN. THIS SYSTEM
WILL MOVE OFF THE COAST LATE WED AND NW FLOW WILL PUSH OVER THE
REGION INTO NEXT WEEKEND. GUSTY WINDS WILL BE A CONCERN W/ THE LOW
PRESSURE SYSTEM...AS WELL AS AFTER THE SYSTEM EXITS AND COLD-DRY NW
FLOW SETTLES IN OVER THE AREA.
MARINE
WINDS WL BE UNDER SCA VALUES TDA AND TNGT. LGT SNOW WL BEGIN TO
FALL THIS AFTN...BECMG HVR AFTR MDNGT AND DCSRG VSBY TO 1/2 MILE
BY MRNG.
WINDS WILL APPROACH SCA CRIT AFT SUNRISE WED...BUT GALE CONDITIONS
WILL QUICKLY BE REALIZED INTO THE MID-LATE MORNING...AS A COASTAL
LOW STRENGTHENS OFF THE MID ATLC...PICKING UP WINDS OVER THE MID
ATLC AND ESPECIALLY OVER THE BAY/TP. THE LOW WILL REACH PEAK
STRENGTH AND PROXIMITY JUST OFF THE COAST FROM WED AFTN INTO EARLY
THU...KEEPING GALE CONDITIONS OVER THE WATERS WELL INTO THE LATE
NIGHT HRS...SOLID SCA AFTER THAT /INTO MUCH OF THU/. NW FLOW WILL
THEN BE COMMON FOR THE REGION INTO THE WEEKEND...W/ INTERMITTENT
PERIODS OF SCA CONDITIONS.
LWX WATCHES/WARNINGS/ADVISORIES
DC...WINTER STORM WARNING FROM NOON TODAY TO 7 PM EST WEDNESDAY FOR
DCZ001.
MD...WINTER STORM WARNING FROM NOON TODAY TO 7 PM EST WEDNESDAY FOR
MDZ003>007-009>011-013-014-016>018.
WINTER STORM WARNING FROM 9 AM THIS MORNING TO 4 PM EST
WEDNESDAY FOR MDZ502.
WINTER STORM WARNING FROM 9 AM THIS MORNING TO 7 PM EST
WEDNESDAY FOR MDZ501.
VA...WINTER STORM WARNING FROM NOON TODAY TO 7 PM EST WEDNESDAY FOR
VAZ030-031-040-042-050>057-501-502.
WINTER STORM WARNING FROM 9 AM THIS MORNING TO 4 PM EST
WEDNESDAY FOR VAZ025>029-036>039.
WINTER STORM WARNING FROM 9 AM THIS MORNING TO 7 PM EST
WEDNESDAY FOR VAZ021.
WV...WINTER STORM WARNING FROM NOON TODAY TO 7 PM EST WEDNESDAY FOR
WVZ052-053.
WINTER STORM WARNING FROM 9 AM THIS MORNING TO 4 PM EST
WEDNESDAY FOR WVZ050-051-055-502-504.
WINTER STORM WARNING FROM 9 AM THIS MORNING TO 7 PM EST
WEDNESDAY FOR WVZ054-501-503.
MARINE...GALE WARNING FROM 8 AM WEDNESDAY TO 6 AM EST THURSDAY FOR
ANZ530>543.
PRODUCTS...WOODY!/GMS
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