Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 200230 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 930 PM EST FRI DEC 19 2014 .SYNOPSIS... HIGH PRESSURE WILL PERSIST THROUGH SUNDAY. LOW PRESSURE WILL TRACK UP THE MID-ATLANTIC COAST MONDAY NIGHT. A STRONG COLD FRONT WILL PASS THROUGH THE AREA WEDNESDAY. && .NEAR TERM /THROUGH SATURDAY/... AS OF 02Z...1024MB WILL PERSIST OVER THE AREA THROUGH SUNDAY NIGHT. CLEAR SKIES EAST OF THE ALLEGHENIES INTO LATE TONIGHT BEFORE STRATUS SPREADS IN FROM THE SOUTHWEST AS AN UPPER-LEVEL TROUGH APPROACHES FROM THE TENNESSEE VALLEY. TEMPS HAVE CRASHED INTO THE 20S IN TYPICAL COOL SPOTS ...LOW 30S ELSEWHERE. MINS JUST A FEW DEGREES LESS AS MIXING PERSISTS WITH 1027MB PRESSURE OVER THE ERN OH VLY. 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 /02Z SATURDAY THROUGH WEDNESDAY/... NW FLOW 5-10 KT INTO LATE TONIGHT BEFORE DIMINISHING. 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... SCA CANCELLED EARLY FOR GUSTS AROUND 15 KT THIS EVENING...EASING THROUGH SATURDAY MORNING AS HIGH PRESSURE BUILDS OVERHEAD. 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...NONE. && $$ SYNOPSIS...BAJ/BJL NEAR TERM...BAJ/BJL SHORT TERM...KS LONG TERM...CEM AVIATION...BAJ/BJL/KS MARINE...BAJ/BJL/KS

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