FXUS61 KLWX 091346
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
846 AM EST WED DEC 9 2009

.SYNOPSIS...
LOW PRESSURE WILL MOVE INTO THE GREAT LAKES AND SOUTHERN CANADA 
TODAY. THE WARM FRONT ASSOCIATED WITH THIS LOW WILL REMAIN OVER THE 
REGION THIS MORNING...BRINGING MORE RAIN. THE COLD FRONT ASSOCIATED 
WITH THIS LOW WILL PASS THROUGH THIS AFTERNOON. HIGH PRESSURE WILL
BUILD IN BEHIND THE COLD FRONT TONIGHT THROUGH FRIDAY...BRINGING
DRY AND VERY COLD CONDITIONS. LOW PRESSURE MAY IMPACT THE REGION
DURING THE WEEKEND.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
HAVE UPDATED THE FORECAST TO ADD EXTREME WESTERN ALLEGANY AND
MINERAL COUNTIES TO THE WIND ADVISORY OUT WEST. ALSO...HAVE
UPDATED THE POPS TO REFLECT CURRENT TRENDS. 

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM THURSDAY/...
CDFNT ASSOCIATED WITH MODIFIED ARCTIC AMS MOVES THRU RGN LATE THIS
AFTN. GUSTY WINDS CONT THRU EARLY THIS EVE BFR TEMPS DROP
DRASTICALLY AND AIR DRIES. UPSLP SNOW PSBL TNGT ALONG WRN SLOPES
OF ALLEGHENY FRONT...BUT ACCUMULATIONS XPCD TO BE AROUND ONE INCH.
SHARPLY COLDER MINIMA AS SKIES CLR AND VERY COLD...DRY AIR ARRIVES.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
MODIFIED ARCTIC AMS ARRIVES THU IN WAKE OF TROF. DIFFERENCES EXIST
BTWN SHORTER RANGE MODELS IN STRENGTH OF COLD AIR. HAVE COOLED
MAXIMA THU AFTN BY A FEW DEG F OVER PREV FCST...HOWEVER IF GFS IS
CORRECT...THERE IS ROOM TO CONT COOLING TREND. COLD AIR RMNS IN
PLACE FRI. DRY WX AS HIPRES BUILDS.

MINIMAL CHGS MADE TO EXTENDED FCST ATTM. PSBLTY OF A BRIEF SNOW
SAT-SAT NGT AS A QUICK-MOVG SHRTWV TROF PASSES TO S AND
STRENGTHENS A COASTAL LOPRES SYSTEM. ANOTHER ARCTIC ORIGIN AMS
ARRIVES BY EARLY NEXT WEEK.

&&

.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
CONTD SUB-VFR CONDITIONS XPCD ALL TERMINALS THRU MID-MRNG. DRY
SLOT ARRIVES AND DIVERTS HEAVY PCPN EWD LATE THIS MRNG. SOME
BREAKS IN CLDS PSBL...BUT DRY AIR ALOFT MAY INVIGORATE A FEW
CNVCTV ELEMENTS BY THIS AFTN...MAINLY VCTY ERN TERMINALS. PRESSURE
GRADIENT INCRS AND MAY PROMOTE GUSTY WINDS AT ALL TERMINALS.

STRONG CDFNT MOVES THRU EARLY THIS EVE...WITH STRONG WLY WINDS
CONTG THRU TNGT. HIPRES BUILDS THU AND FRI.

SUB-VFR CIGS AND VSBYS PSBL SAT-SAT NGT AS A QUICK-MOVG SHRTWV
TROF COULD YIELD A BRIEF PERIOD OF RAIN OR SNOW. HIPRES BUILDS
AGAIN EARLY NEXT WEEK.

&&

.MARINE...
SMALL CRAFT ADZY CANCELLED THIS MRNG FOR UPR AND MIDDLE PORTIONS
OF TIDAL POTOMAC GIVEN CURRENT OBS. ONSET OF 20 KT GUSTS WAS
DELAYED UNTIL MID-DAY...WHEN DRY SLOT ARRIVES AND LIMITED MIXING
ENSUES.

LWR PORTIONS OF MD CHSPK BAY AND LWR TIDAL POTOMAC UPGRADED TO
GALE WRNG AS COASTAL FRONT XPCD TO BISECT THESE ZONES.

SMALL CRAFT ADZY CONTS...AND GALE WRNG SPREADS NWD...TNGT AS
STRONG CDFNT MOVES ACRS WATERS AND YIELDS WLY WINDS WITH GUSTS UP
TO 40 KT XPCD.

STRONG WINDS MAY CONT INTO THU...BUT ATTM DURATION AND STRENGTH OF
WINDS UNCERTAIN.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR VAZ021-025-026-
     036.
WV...WIND ADVISORY UNTIL 10 PM EST THIS EVENING FOR WVZ054-501-502.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ532-
     533-540-541.
     GALE WARNING FROM 6 PM THIS EVENING TO 6 AM EST THURSDAY FOR 
     ANZ532-533-540-541.
     SMALL CRAFT ADVISORY UNTIL 6 AM EST THURSDAY FOR ANZ530-531-
     538-539-542.
     GALE WARNING UNTIL 6 AM EST THURSDAY FOR ANZ534-537-543.
     SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 6 AM EST 
     THURSDAY FOR ANZ535-536.

&&

$$
UPDATE...LISTEMAA