FXUS61 KLWX 031620
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1120 AM EST THU DEC 3 2009

.SYNOPSIS...
DEEP LOW PRESSURE OVER LAKE ERIE WILL TRACK NORTHEAST TO NEW ENGLAND 
THIS AFTERNOON. ATMOSPHERIC PRESSURE BUILDS NOW THROUGH FRIDAY NIGHT. A 
COASTAL LOW DEVELOPS OFF THE CAROLINAS SATURDAY BEFORE TRACKING 
NORTHEAST OFF THE MID ATLANTIC COAST SATURDAY NIGHT. HIGH PRESSURE 
WILL RETURN FOR SUNDAY AND MONDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
ADJUSTED TEMPS AND SKY COVER BASED ON CURRENT SATL/OBS TRENDS.
GUSTINESS IS HAVING A SLOW START AS MIXING APPEARS TO BE DELAYED...SO
HAVE BACKED A BIT. OTHERWISE NO SIGNIFCANT CHANGES AS FRONT
CONTINUE TO MOVE EAST ACROSS THE BAY.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/...
TONIGHT...UPSLOPE SNOW FOR ALLEGHENY FRONT...AROUND AN INCH OF 
ACCUMULATION. TIMING OF SNOW CHANGEOVER AND MOISTURE AVAILABILITY 
KEYS TO WHETHER TWO INCHES /AND A WINTER WX ADVISORY/ IS POSSIBLE. 
THINKING TRANSITION WILL BE THIS EVENING AND INTENSITY TO DROP OFF 
THROUGH THE NIGHT...SO NO ADVISORY AT THIS TIME.

EAST OF THE ALLEGHENY FRONT...WHETHER THE BALT-DC METRO AREAS REACH 
32F DEPENDS ON MIXING AND HIGH CLOUD COVER...THINKING MID 30S ATTM.

FRIDAY...HIGH PRESSURE BUILDING IN. HOWEVER...MOSTLY SUNNY MORNING 
GIVES WAY MID/HIGH CLOUD COVER AS PRECURSOR TO COASTAL DEVELOPMENT 
OFF CAROLINAS FOR SATURDAY BUILDS NWARD BY FRIDAY AFTERNOON/EVENING. 
UPPER 40S TO NEAR 50F MAXT.

UPSLOPE SNOW TAPERS OFF COMPLETELY FRIDAY MORNING.

&&

.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
NOT MANY CHANGES TO THE LONG TERM FORECAST MADE. POPULATED WITH NEW 
WIND/MAX AND MIN T GRIDS FOR FRIDAY NIGHT INTO SATURDAY. 

RIDGE OF HIGH PRESSURE ACROSS THE CWFA WILL SHIFT SLIGHTLY TO THE 
NORTH EARLY SATURDAY AS A COASTAL LOW PRESSURE SYSTEM EMERGES OFF 
THE SOUTHEAST US COAST. THE LOW CENTER IS EXPECTED TO MOVE UP THE 
MIDDLE ATLANTIC COAST THROUGH SUNDAY. HIGH PRESSURE BUILDS IN LATE 
SUNDAY AND REMAINS ACROSS THE AREA THROUGH TUESDAY. THE NEXT 
FRONTAL/LOW PRESSURE SYSTEM IS EXPECTED FOR MID WEEK.

TEMPERATURES FOR SATURDAY ARE NOT EXPECTED TO RISE MUCH OUT OF THE 
30S FOR MOST LOCALES...WITH LOWER SOUTHERN MARYLAND IN THE LOWER 
40S. SNOW SHOWERS ARE EXPECTED IN THE HIGHER ELEVATIONS...WITH A 
RAIN/SNOW MIX MOST EVERYWHERE ELSE. LOWER SOUTHERN MARYLAND MAY STAY 
WARM ENOUGH FOR ALL RAIN.

&&

.AVIATION /16Z THURSDAY THROUGH MONDAY/...
STRONG SWLY WINDS WITH GUSTS 25 TO 30 KT BEHIND FROPA THROUGH
MIDDAY BEFORE DIMINISHING AS GRADIENT SLACKENS AND WINDS TURN WLY
THIS AFTERNOON.

SUB VFR CONDITIONS EXPECTED ON SATURDAY AS A LOW PRESSURE CENTER 
MOVES UP THE EAST COAST. NO VSBY/CIG RESTRICTIONS EXPECTED FROM 
SUNDAY THROUGH TUESDAY.

&&

.MARINE...
DROPPED GALE WARNING PER OBS SWLY 25 TO 30 KT OUTSIDE OF
CONVECTIVE GUSTS. STRONG SCA CONDITIONS THROUGH THE AFTERNOON
BEFORE THE GRADIENT BEGINS TO SLACKEN...SCA NOW UP THROUGH TONIGHT
/ALL ZONES TONIGHT EXCEPT UPPER TIDAL POTOMAC AND PATAPSCO/ WITH
NLY CHANNELING POSSIBLE LATE TONIGHT MAINTAINING THREAT TO MARINE
INTERESTS.

NWLY WINDS CONTINUE FRIDAY...10 TO 15 KT...BEFORE A COASTAL SYSTEM 
DEVELOPS OFF THE CAROLINAS ON SATURDAY.

SMALL CRAFT CONDITIONS ARE POSSIBLE SATURDAY AND SUNDAY AS A LOW 
PRESSURE SYSTEM MOVES UP THE EASTERN SEABOARD.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST FRIDAY FOR ANZ530>534-537-
     539>543.
     SMALL CRAFT ADVISORY UNTIL 6 PM EST THIS EVENING FOR ANZ535-
     536-538.

&&

$$
SYNOPSIS...BAJ
NEAR TERM...LEE 
SHORT TERM...BAJ 
LONG TERM...NWL/GMS/ABW
AVIATION...BAJ 
MARINE...BAJ