Area Forecast Discussion
Issued by NWS Sterling, VA

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000
FXUS61 KLWX 191800
AFDLWX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
100 PM EST FRI DEC 19 2014

.SYNOPSIS...
HIGH PRESSURE WILL BUILD OVERHEAD THIS AFTERNOON...THEN PERSIST
THROUGH SUNDAY. LOW PRESSURE WILL TRACK UP THE MID-ATLANTIC COAST
MONDAY THROUGH MONDAY NIGHT. A STRONG COLD FRONT WILL PASS THROUGH
THE AREA WEDNESDAY.

&&

.NEAR TERM /THROUGH SATURDAY/...
SURFACE HIGH PRESSURE WILL CONTINUE TO BUILD TOWARD THE REGION
FROM THE OHIO VALLEY THIS AFTERNOON. A NORTHWEST FLOW AHEAD OF
THE HIGH WILL CAUSE SEASONABLY CHILLY CONDITIONS DURING THIS TIME.

THERE WILL BE JUST ENOUGH MOISTURE UNDERNEATH THE SUBSIDENCE
INVERSION FOR A BKN STRATOCU DECK ACROSS THE NORTHERN AND CENTRAL
PORTIONS OF THE CWA. FURTHER SOUTH ACROSS CENTRAL
VIRGINIA...PLENTY OF SUNSHINE IS EXPECTED DUE TO THE DOWNSLOPING
NORTHWEST FLOW.

HIGH PRESSURE WILL BUILD OVERHEAD TONIGHT. THE STRATO CU DECK
SHOULD BREAK ACROSS MOST AREAS THIS EVENING...BUT HIGH AND MID-
LEVEL CLOUDS WILL INCREASE FROM SOUTHWEST TO NORTHEAST LATER
TONIGHT AS AN UPPER-LEVEL DISTURBANCE APPROACHES FROM THE
TENNESSEE VALLEY. MIN TEMPS WILL RANGE FROM THE LOWER 20S IN THE
MOUNTAINS TO THE LOWER AND MIDDLE 30S IN DOWNTOWN WASHINGTON AND
BALTIMORE.

THE UPPER-LEVEL DISTURBANCE WILL PASS THROUGH THE REGION SATURDAY.
THIS WILL CAUSE SURFACE LOW PRESSURE TO DEVELOP OFF THE SOUTH
CAROLINA COAST...BUT IT WILL BE TOO FAR TO OUR SOUTH FOR ANY
PRECIPITATION. HOWEVER...MOSTLY CLOUDY SKIES ARE EXPECTED AS HIGH
AND MID-LEVEL CLOUDS PASS THROUGH WITH THE UPPER-LEVEL
DISTURBANCE. SEASONABLY CHILLY CONDITIONS WILL CONTINUE BUT WINDS
WILL BE LIGHT. MAX TEMPS WILL RANGE FROM THE UPPER 20S AND LOWER
30S IN THE ALLEGHENY HIGHLANDS TO THE LOWER AND MIDDLE 40S IN
CENTRAL VIRGINIA.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
LARGE SURFACE HIGH PRESSURE WILL EXTEND FROM SOUTHEASTERN CANADA
THROUGH THE MIDDLE ATLANTIC AND INTO THE SOUTHEASTERN CONUS SATURDAY
NIGHT. A WEAK UPPER TROUGH WILL MOVE THROUGH THE AREA...RESULTING IN
A MID-LEVEL CLOUD DECK OVER THE AREA. GIVEN THE CLOUD
COVER...FAVORED THE WARMER MET GUIDANCE FOR LOW TEMPS.  IT WILL BE A
COLD NIGHT...WITH LOWS IN THE 20S OVER NEARLY ALL OF THE FORECAST
AREA. DOWNTOWN AREAS OF BALTIMORE AND WASHINGTON MAY STAY AT OR JUST
ABOVE FREEZING OVERNIGHT.

THE HIGH WILL BE DIRECTLY OVERHEAD SUNDAY...WITH MOSTLY SUNNY SKIES
AND LIGHT WINDS. SOME DISCREPANCY AMONG MODELS AS TO WHETHER THE
RIDGE AXIS WILL MAKE IT TO THE DELMARVA BY THE AFTERNOON...WHICH
WOULD RESULT IN LIGHT RETURN FLOW ACROSS THE SOUTHERN AND WESTERN
COUNTIES OF THE CWA. HIGH EXPECTED TO BE IN THE MID TO UPPER 40S
ACROSS MOST OF THE CWA...WITH LOW 40S POSSIBLE NEAR THE MASON DIXON
LINE AND IN HIGHER ELEVATIONS.

ONLY GRADUAL EWD MOVEMENT IN THE RIDGE AXIS TOWARDS THE COAST SUNDAY
NIGHT. MODELS HAVE TRENDED SLOWER IN THE DEVELOPMENT OF LOW PRESSURE
ALONG THE SOUTHEAST COAST. REMOVED ALL POPS FROM THE CWA SUNDAY
NIGHT ACCORDINGLY. LOWS WILL BE SIMILAR TO SATURDAY NIGHT...IN THE
20S FOR MOST OF THE CWA AND A FEW SPOTS ABOVE 30 IN METRO
BALTIMORE/WASHINGTON.


&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
PVA MAX IN SOUTHERN FLOW WILL SUPPORT WIDESPREAD PRECIPITATION
ACROSS REGION MONDAY. ALTHOUGH MOST OF PRECIPITATION LOOKS TO LIQUID
IT APPEARS THAT ENOUGH COLD AIR IS IN PLACE FOR PRECIPITATION BEGIN
AS A WINTRY MIX EARLY MONDAY.

STRONG COLD FRONT SUPPORTED BY UPPER LEVEL CUT-OFF SOUTH OF THE
GREAT LAKES WILL CROSS THE MID ATLANTIC STATES BY WEDNESDAY. RAIN
WILL CHANGE OVER TO SNOW IN AREA AFFECTED BY MUCH COLDER AIR
STREAMING INTO REGION BEHIND THE LOW.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
A BKN STRATOCU DECK IS EXPECTED ACROSS MOST OF THE TERMINALS
THROUGH THIS AFTERNOON. CIGS SHOULD REMAIN ABOVE 3KFT. NORTHWEST
WINDS WILL GUST AROUND 15 TO 20 KNOTS THROUGH THIS AFTERNOON
BEFORE DIMINISHING AROUND SUNSET. HIGH PRESSURE WILL BUILD OVER
THE TERMINALS TONIGHT THROUGH SATURDAY. VFR CONDITIONS WILL
CONTINUE.

HIGH PRESSURE WILL BE DIRECTLY OVERHEAD SATURDAY NIGHT THROUGH
SUNDAY NIGHT. VFR CONDITIONS EXPECTED WITH LIGHT WINDS. LOW
PRESSURE MAY BRING PRECIPITATION AND SUBVFR CONDITIONS MONDAY AND
TUESDAY. A STRONG COLD MAY IMPACT THE TERMINALS WEDNESDAY.

&&

.MARINE...
NW WINDS WILL CONTINUE TODAY AS HIGH PRESSURE APPROACHES FROM THE
WEST. A SMALL CRAFT ADVISORY IS IN EFFECT FOR THE WATERS DURING
THIS TIME. HIGH PRESSURE WILL BUILD OVER THE TONIGHT THROUGH
SATURDAY. A SMALL CRAFT ADVISORY IS IN EFFECT FOR THIS EVENING
ACROSS THE MARYLAND CHESAPEAKE BAY FROM SANDY POINT TO SMITH POINT
AND THE LOWER TIDAL POTOMAC RIVER FROM COBB ISLAND TO SMITH POINT.

HIGH PRESSURE WILL BE DIRECTLY OVER THE WATERS SATURDAY NIGHT
THROUGH SUNDAY NIGHT. LIGHT NORTHERLY FLOW SATURDAY NIGHT AND
SUNDAY...SHIFTING TO THE E-NE SUNDAY NIGHT. LOW PRESSURE MAY
IMPACT THE WATERS MONDAY INTO TUESDAY BEFORE A STRONG COLD FRONT
PASSES THROUGH WEDNESDAY.



&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...NONE.
MD...NONE.
VA...NONE.
WV...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 5 PM EST THIS AFTERNOON FOR ANZ530-
     531-535-536-538-539-542.
     SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TONIGHT FOR ANZ532>534-
     537-540-541-543.

&&

$$
SYNOPSIS...BJL
NEAR TERM...BJL
SHORT TERM...KS
LONG TERM...CEM
AVIATION...BJL/KS
MARINE...BJL/KS






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