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000
FXUS61 KLWX 110230
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
930 PM EST TUE DEC 10 2013

.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVER THE REGION TONIGHT. A REINFORCING
COLD FRONT WILL MOVE THROUGH THE AREA LATE WEDNESDAY AFTERNOON AND
EVENING. ARCTIC HIGH PRESSURE WILL BUILD OVERHEAD THROUGH THE END
OF THE WEEK. LOW PRESSURE MAY IMPACT THE REGION THIS WEEKEND.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
1030MB SFC HIGH CENTERED OVER LWR/MID MS RVR VLY THIS EVE. THE
PRESSURE GRADIENT BETWEEN THIS HIGH AND ONE COLD FRONT OVER THE WRN
ATLANTIC AND ANOTHER MOVING THRU THE GREAT LAKES WILL PRODUCE A WLY
WIND THIS EVE. WINDS BE BREEZY ALONG THE WRN RIDGES...GUSTING 30-40
MPH...AND GENERALLY LIGHTER IN THE VLYS /WHERE THERMO PROFILES ARE
MORE STABLE/. IN SHELTERED VLYS /WHERE THERE IS A FRESH SNOWPACK AND
WINDS LIKELY GO CALM/...TEMPS WILL DROP QUICKLY INTO THE TEENS.
RAISED MIN TEMPS SEVERAL DEGREES FROM PREV FCST MOST NOTABLY IN
PARTS OF CENTRAL VA AND SRN MD...WHERE THERE IS LESS OF A SNOWPACK.
THE BIGGEST CONCERN FOR TNGT IS ICY ROADS TNGT WITH ANY MELTED
SNOW/SLUSH FROM TDA FREEZING OVER. HAVE ALREADY RECEIVED REPORTS IN
NRN MD AND ERN WV OF ACCIDENTS DUE TO ICY ROADS. AN SPS FOR BLACK
ICE WAS ISSUED TO ALERT THE PUBLIC.

HIPRES WILL CONTINUE TO BUILD EWD ON WED...WITH THE CENTER
REACHING THE SRN MID-ATLANTIC STATES DURING THE DAY. A COLD FRONT
WILL PASS THRU THE NWRN PART OF THE CWA LATE IN THE DAY. DESPITE
PLENTY OF SUNSHINE...TEMPS MAY REMAIN BELOW FREEZING THRUOUT THE DAY
ACROSS NRN MD...NRN VA AND ERN WV. FROM DC SOUTHWARD...HIGHS ARE ONLY
IN THE MID 30S.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
A WEAK COLD FRONT WILL PASS THROUGH THE AREA WEDNESDAY EVENING.
THE FRONT MAY BE ACCOMPANIED BY A PERIOD OF UPSLOPE SNOW SHOWERS
ALONG THE ALLEGHENY FRONT. LGT SNOW ACCUMULATION /UNDER 1 INCH/
IS POSSIBLE. ELSEWHERE...DRY WX EXPECTED.

ARCTIC HIGH PRESSURE BUILD INTO THE MID ATLANTIC BEHIND THE COLD
FRONT...LEADING TO A PERIOD OF COLD WEATHER FOR THE REGION THRUOUT
THE PERIOD. TEMPS WILL BE 10-20F BELOW NORMAL WED NGT THRU THU
NGT.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
HIGH PRESSURE WILL PASS OVERHEAD ON FRIDAY AND MOVE OUT TO SEA
EARLY SATURDAY MORNING.

A COLORADO LOW IS EXPECTED TO FORM MIDWEEK AND TRAVEL CLOSE TO
THE GULF STATES BEFORE MAKING A TURN UP THE TN VALLEY AND TOWARDS
THE MID ATLANTIC. BOTH THE GFS AND ECMWF ARE ON BOARD WITH A
DOUBLE-BARREL LOPRES SYSTEM IMPACTING THE MID-ATLANTIC REGION THIS
WEEKEND. MODELS IN AGREEMENT WITH A 1035 MB HIGH PRESSURE SETTING
UP OVER MAINE...WHICH SHOULD ACT AS A BLOCKING HIGH AND ESTABLISH
ANOTHER COLD AIR DAMMING SETUP FOR THE WEEKEND EVENT...HELPING TO
KEEP COLD AIR WEDGED IN NEAR THE SFC FOR AT LEAST THE ONSET OF
PRECIP ON SATURDAY. OVERALL PTYPE AND TIMING SPECIFICS ARE STILL
IN QUESTION...BUT THE POTENTIAL FOR A WINTRY MIX EXISTS.

LOW PRESSURE MOVES TOWARDS NEW ENGLAND SUNDAY AND BREEZY COOLER
CONDITIONS ARE EXPECTED FOR THE MID ATLANTIC AS HIGH PRESSURE
MOVES BACK INTO THE REGION SUNDAY. HAVE INCLUDED UPSLOPE SNOW FOR
HIGH ELEVATIONS NEAR THE ALLEGANY FRONT OVERNIGHT SUNDAY WITH A
NWLY FETCH FROM THE GREAT LAKES DURING THIS TIME.

&&

.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
VFR CONDITIONS TNGT AND WED. WLY WINDS 5-10 KT BECOME SWLY BY WED
AFTN. A FEW GUSTS T0 20 KT POSSIBLE LATE THIS EVE.

A PRESSURE SURGE BEHIND A COLD FRONT WILL CAUSE WINDS TO INCREASE
LATE WEDNESDAY NIGHT THROUGH THURSDAY. WINDS WILL SHIFT FROM
SOUTHWEST TO NORTHWEST BEHIND THE FRONT E WITH GUSTS AROUND
20 KNOTS. WINDS WILL DIMINISH THURSDAY NIGHT.

VFR CONDITIONS ARE EXPECTED FOR THE END OF THE WORKWEEK. LOW
PRESSURE MAY IMPACT THE TERMINALS DURING THE WEEKEND.

&&

.MARINE...
A SMALL CRAFT ADVISORY IS IN EFFECT FOR THE WATERS TONIGHT AHEAD OF
BUILDING HIGH PRESSURE. DESPITE A WEAK GRADIENT...THE RELATIVELY
WARMER WATERS SHOULD ALLOW FOR ENOUGH MIXING TO BRING STRONGER WINDS
FROM ALOFT DOWN TO THE SURFACE...ESPECIALLY ACROSS THE MIDDLE
PORTION OF THE BAY AND LOWER TIDAL POTOMAC RIVER. ELSEWHERE THE SCA
MAY TURN OUT TO BE MORE MARGINAL.

A SMALL CRAFT ADVISORY IS IN EFFECT FOR ALL WATERS LATE WEDNESDAY
NIGHT AND THURSDAY. LOW PRESSURE MAY IMPACT THE WATERS DURING THE
WEEKEND.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EST WEDNESDAY FOR ANZ530>543.
     SMALL CRAFT ADVISORY FROM MIDNIGHT WEDNESDAY NIGHT TO 6 PM EST
     THURSDAY FOR ANZ530>543.

&&

$$
SYNOPSIS...BJL/JRK
NEAR TERM...JRK
SHORT TERM...JRK/KLW
LONG TERM...CEB/JRK
AVIATION...BJL/CEB/KLW
MARINE...BJL/CEB/KLW