-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KLWX 030845
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
345 AM EST TUE DEC 3 2013

.SYNOPSIS...
-- Changed Discussion --
WEAK HIGH PRESSURE OVERHEAD TODAY WILL MOVE OFF THE COAST TONIGHT
THROUGH WEDNESDAY. A COLD FRONT WILL SLOWLY APPROACH THE REGION
THURSDAY BEFORE PASSING THROUGH THURSDAY NIGHT THROUGH FRIDAY NIGHT.
WAVES OF LOW PRESSURE WILL DEVELOP ALONG THE FRONT...BRINGING
UNSETTLED CONDITIONS DURING THIS TIME. HIGH PRESSURE WILL BRIEFLY
BUILD OVERHEAD SATURDAY BEFORE LOW PRESSURE IMPACTS THE AREA SUNDAY
INTO EARLY NEXT WEEK.
-- End Changed Discussion --

&&

.NEAR TERM /TODAY AND TONIGHT/...
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UPPER TROF AXIS IS OVER WEST VIRGINIA EARLY THIS MORNING. MODELS
MOVE IT THROUGH THE DC AREA AROUND 7 AM AND THEN WEAK HIGH PRESSURE
BUILDS IN. PERSISTENT CLOUD DECK AROUND 6K TO 7K FEET IS KEEPING
TEMPERATURES RELATIVELY MILD THIS MORNING...AND IS ALSO LIMITING
FOG DEVELOPMENT. HIGHER CLOUDS ARE ALSO DRIFTING OVERHEAD AS A NEARLY
STATIONARY FRONT OVER THE OHIO VALLEY NUDGES A BIT CLOSER TO US.

LIGHT ECHOES NOTED ON KLRX RADAR EXPECT THAT VERY LITTLE...IF ANY IS
REACHING THE GROUND. LIGHT SHOWERS / SPRINKLES REMAIN POSSIBLE FOR A
FEW MORE HOURS FROM THE POTOMAC HIGHLANDS TO PORTIONS OF THE
SHENANDOAH VALLEY. AS THE TROF DEPARTS TO THE EAST...EXPECT PARTIAL
CLEARING OF SKIES LATER THIS MORNING AND AFTERNOON. MILD HIGH
TEMPERATURES IN THE 50S ARE LIKELY SOUTH OF DC AND ABOVE ANY
INVERSIONS THAT LINGER TODAY...WITH COOLER 40S IN THE MOUNTAINS AND
SHELTERED AREAS.
-- End Changed Discussion --

&&

.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
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HIGH PRESSURE WILL MOVE OFF THE COAST AND A WARM FRONT WILL LIFT
NORTH INTO OUR REGION LATER WEDNESDAY AND WEDNESDAY NIGHT.
ISENTROPIC LIFT ASSOCIATED WITH THE WARM FRONT WILL CAUSE LOW CLOUDS
TO DEVELOP WHILE HIGH AND MID-LEVEL CLOUDS MOVE THROUGH IN THE
SOUTHWEST FLOW ALOFT. THEREFORE...SKIES ARE EXPECTED TO TURN OUT
MAINLY CLOUDY DURING THIS TIME. LITTLE OR NO PRECIPITATION IS
EXPECTED SINCE FORCING AHEAD OF THE WARM FRONT WILL BE WEAK AND
ISENTROPIC LIFT WILL BE SHALLOW. HOWEVER...A COUPLE SHOWERS CANNOT
BE RULED OUT WEDNESDAY MORNING ACROSS CENTRAL VIRGINIA AND SOUTHERN
MARYLAND AS SHORTWAVE ENERGY PASSES THROUGH IN THE SOUTHWEST FLOW
ALOFT. PATCHY DRIZZLE IS POSSIBLE...ESPECIALLY WEDNESDAY NIGHT.

MAX TEMPS WILL BE NEAR OR SLIGHTLY ABOVE CLIMO WEDNESDAY...DESPITE
THE CLOUD COVER. MIN TEMPS WILL BE WELL ABOVE CLIMO WEDNESDAY NIGHT.
MAX TEMPS WEDNESDAY WILL BE IN THE LOWER TO MIDDLE 50S ACROSS MOST
LOCATIONS WITH UPPER 50S POSSIBLE ACROSS PORTIONS OF CENTRAL
VIRGINIA AND EASTERN WEST VIRGINA. MIN TEMPS WEDNESDAY NIGHT WILL
RANGE FROM THE MIDDLE 40S ACROSS PORTIONS OF THE POTOMAC HIGHLANDS
TO THE UPPER 40S AND LOWER 50S ELSEWHERE.
-- End Changed Discussion --

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
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AN UPPER-LEVEL TROUGH WILL REMAIN OVER THE NORTH-CENTRAL CONUS INTO
THE ROCKIES WHILE THE SUBTROPICAL RIDGE STRENGTHENS OVER THE
SOUTHEASTERN CONUS. A SOUTHWEST FLOW IS EXPECTED ALOFT IN BETWEEN
THESE SYSTEMS ACROSS OUR AREA.

LOW PRESSURE WILL BECOME VERTICALLY STACKED AS IT TRACKS TOWARD THE
HUDSON BAY THURSDAY. THE COLD FRONT ASSOCIATED WITH THIS LOW WILL
SLOWLY TRACK SOUTHEAST FROM THE OHIO VALLEY TOWARD OUR AREA. THE
WARM FRONT OVER THE REGION THURSDAY MORNING SHOULD LIFT OFF TO OUR
NORTH AND EAST. A SOUTHERLY FLOW AHEAD OF THE COLD FRONT AND BEHIND
THE WARM FRONT SHOULD ALLOW FOR UNUSUALLY MILD CONDITIONS FOR THIS
TIME OF YEAR THURSDAY. DESPITE PLENTY OF CLOUDS...MAX TEMPS SHOULD
REACH THE 60S ACROSS MOST LOCATIONS. A FEW SHOWERS ARE POSSIBLE
THURSDAY...BUT MUCH OF THE TIME SHOULD TURN OUT DRY. THE BEST CHANCE
FOR SHOWERS WILL BE ACROSS WESTERN MARYLAND AND EASTERN WEST
VIRGINIA THURSDAY AFTERNOON...CLOSER TO THE FRONT.


THE COLD FRONT WILL BE SLOW TO MOVE THROUGH OUR AREA THURSDAY NIGHT
THROUGH FRIDAY NIGHT. THE EXACT TIMING OF THE FRONTAL PASSAGE
REMAINS UNCERTAIN AT THIS TIME...BUT WAVES OF LOW PRESSURE RIDING
ALONG THE COLD FRONT ALONG WITH WARM AND MOIST AIR OVERRUNNING THE
LOW-LEVEL COLD AIR BEHIND THE FRONT WILL RESULT IN RAINFALL ACROSS
THE AREA. VERY MILD CONDITIONS ARE EXPECTED AHEAD OF THE FRONT...BUT
IT WILL TURN OUT SHARPLY COLDER BEHIND THE FRONT. RAIN MAY END AS A
LITTLE SNOW FRIDAY NIGHT...ESPECIALLY IN THE MOUNTAINS. ANY
ACCUMULATION WILL BE LIGHT AND CONFINED MOST LIKELY TO LOCATIONS
ALONG AND WEST OF THE ALLEGHENY FRONT.

HIGH PRESSURE WILL RETURN BRIEFLY FOR SATURDAY...BUT LOW PRESSURE
MAY IMPACT THE AREA SUNDAY INTO MONDAY. DETAILS ARE UNCERTAIN AT
THIS TIME...BUT THE STRONG SUBTROPICAL RIDGE SUGGESTS THAT THE
PRIMARY LOW WILL TRACK TO OUR WEST. THIS MEANS THAT WARMER AIR IS
LIKELY TO BE DRAWN INTO THE SYSTEM. HOWEVER...COLD HIGH PRESSURE TO
OUR NORTH WILL BE SLOW TO RETREAT AND THERE SHOULD BE PLENTY OF
LOW-LEVEL COLD AIR AHEAD OF THE STORM SYSTEM. THEREFORE...A WINTRY
MIX IS POSSIBLE BEFORE WARMER AIR EVENTUALLY WORKS ITS WAY INTO THE
AREA.
-- End Changed Discussion --

&&

.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
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VFR CONDITIONS THRU 12Z AT THE BWI...DCA AND IAD TERMINALS. CIGS
BKN-OVC070 WITH LIMITED MVFR 5SM BR POSSIBLE AROUND SUNRISE. VFR
PERSISTS INTO THE AFTERNOON WITH CLEARING SKIES. SFC WINDS LIGHT
180-220 LESS THAN 05KTS. WINDS ABOVE 1000 FEET WILL BE FROM THE NE
UNTIL LATER THIS MORNING...WITH DIRECTIONAL DIFFERENCES CAUSING SOME
TURBULENCE THIS MORNING. WINDS ALOFT BACK TO THE SOUTHWEST AND
INCREASE LATER TODAY.

A WARM FRONT WILL APPROACH THE REGION WEDNESDAY BEFORE PASSING
THROUGH WEDNESDAY NIGHT INTO THURSDAY MORNING. CIGS WILL LOWER
WEDNESDAY AND IFR CONDITIONS ARE LIKELY WEDNESDAY NIGHT INTO
THURSDAY ALONG WITH AREAS OF DRIZZLE.

CIGS/VSBYS MAY IMPROVE BEHIND THE WARM FRONT LATER THURSDAY...BUT A
COLD FRONT WILL SLOWLY PASS THROUGH THURSDAY NIGHT THROUGH FRIDAY
NIGHT. RAIN AND SUBVFR CIGS/VSBYS ARE EXPECTED DURING THIS TIME.
HIGH PRESSURE WILL BUILD OVERHEAD SATURDAY.
-- End Changed Discussion --

&&

.MARINE...
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WINDS WILL BE LIGHT AND NORTHERLY OVERNIGHT BECOMING MORE EASTERLY
THEN SOUTHEASTERLY AT 5 TO 10 KNOTS WITH GUSTS TO AROUND 15 KNOTS
THIS AFTERNOON AND TONIGHT.

WARM FRONT WILL APPROACH THE WATERS WEDNESDAY BEFORE PASSING
THROUGH WEDNESDAY NIGHT INTO THURSDAY. WINDS SHOULD REMAIN BELOW
SCA CRITERIA THROUGH THURSDAY MORNING.

A COLD FRONT WILL APPROACH THE AREA LATE THURSDAY BEFORE PASSING
THROUGH THURSDAY NIGHT THROUGH FRIDAY NIGHT. HIGH PRESSURE WILL
BRIEFLY BUILD TOWARD THE WATERS SATURDAY BEFORE LOW PRESSURE IMPACTS
THE WATERS EARLY NEXT WEEK. A SMALL CRAFT ADVISORY MAY BE NEEDED FOR
PORTIONS OF THE WATERS THURSDAY AFTERNOON THROUGH SUNDAY.
-- End Changed Discussion --

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...NONE.

&&

$$

SYNOPSIS...BJL/SDG
NEAR TERM...SDG
SHORT TERM...SDG
LONG TERM...BJL
AVIATION...SDG/BJL
MARINE...SDG/BJL