Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 120752 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 352 AM EDT FRI SEP 12 2014 .SYNOPSIS...
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A COLD FRONT WILL STALL ACROSS THE CAROLINAS TODAY. AN UPPER LEVEL DISTURBANCE WILL PASS THROUGH THE AREA EARLY SATURDAY. HIGH PRESSURE OVER THE GREAT LAKES WILL EXTEND SOUTH INTO THE MID ATLANTIC SUNDAY AND MONDAY.
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&& .NEAR TERM /THROUGH TONIGHT/...
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COOLER AND DRIER AIR WILL FILTER INTO THE REGION ON NNW WINDS TODAY. THE FRONTAL BOUNDARY HAS PUSHED SOUTH OF THE FORECAST AREA EARLY THIS MORNING AND WILL CONTINUE TO DRIFT SOUTH AS HIGH PRESSURE BUILDS IN ACROSS THE GREAT LAKES. TEMPERATURES THIS AFTERNOON WILL TOP OUT 10 TO 15 DEGREES COOLER THAN YESTERDAY AND WITH NOTICEABLY LESS HUMIDITY. THE OLD FRONTAL BOUNDARY IS EXPECTED TO STAY SOUTH OF THE FORECAST AREA LEAVING THE CWFA HIGH AND DRY FOR MUCH OF THE DAY...EVEN ACROSS SOUTHERN PORTIONS OF THE REGION. MOISTURE LEVELS WILL GRADUALLY INCREASE TONIGHT AS WINDS SHIFT AROUND TO THE EAST AND SOUTHEAST. AN UPPER LEVEL TROUGH WILL TRACK ACROSS THE GREAT LAKES DURING THE OVERNIGHT. PVA/LIFT ASSOCIATED WITH THIS FEATURE WILL INCREASE OVER THE FORECAST AREA LEADING TO SHOWERS DEVELOPING FROM SW-NE OVERNIGHT INTO EARLY SATURDAY MORNING.
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&& .SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
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BEST CHANCE FOR SHOWERS WILL OCCUR SATURDAY MORNING INTO THE AFTERNOON HOURS. INCREASED POPS TO LIKELY AREAWIDE DURING THE 12-18Z TIMEFRAME. BOUNDARY LAYER CONDITIONS APPEAR TO STABLE FOR CONVECTIVE ACTIVITY WITH THIS FAST MOVING SYSTEM. SHOWERS WILL END FROM WEST TO EAST LATE IN THE DAY/NIGHT. DAYTIME TEMPERATURES WILL ONLY TOP OUT IN THE 60S TO LOWER 70S WITH OVERNIGHT LOWS IN THE UPPER 40S TO 50S IN THE COOLER LOCATIONS...NEAR 60 IN THE METRO AREAS.
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&& .LONG TERM /SUNDAY THROUGH THURSDAY/...
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THE WEEK AHD WL LARGELY BE DOMINATED BY SFC HIPRES OVER THE GRTLKS/NEW ENGLAND...AND H5 ZNL FLOW. THIS PTTN WL BE INTERRUPTED ONLY BRIEFLY MON NGT-TUE AS A CDFNT DROPS ACRS THE RGN. UPA SUPPORT REMAINS N OF AREA...SO AM ONLY GOING W/ CHC POPS AND NO THUNDER. DEWPTS WL BE RISING ABV 60F PRIOR TO CFP...OTRW WE/LL BE IN THE COMFY 50S. THUS IT/LL BE A MILD STRETCH...ALMOST A LTL COOL. MAXT WL BE IN THE LWR-MID 70S. USED THE DEWPTS AS A MIN-T GUIDE.
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&& .AVIATION /08Z FRIDAY THROUGH TUESDAY/...
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VFR CONDITIONS EXPECTED TODAY THROUGH TONIGHT AT THE TERMINALS. SHOWERS WILL INCREASE IN COVERAGE OVERNIGHT FROM SW-NE SPREADING ACROSS THE TERMINALS SATURDAY MORNING. SUB VFR CIGS AND VSBYS EXPECTED IN SHOWERS DURING THE DAY THEN IMPROVING LATE. MVFR PSBL MON NGT-TUE AS A COLD FRONT DROPS ACRS THE TERMINALS. DEPENDING UPON TIMING...THE MVFR MAY EVEN START LT MON INVOF CHO. OTRW...VFR WL PREVAIL UNDER HIPRES.
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&& .MARINE...
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SMALL CRAFT CONDITIONS EXPECTED ON THE WATERS THIS MORNING FOLLOWED BY DIMINISHING WINDS AS HIGH PRESSURE NOSES IN FROM THE WEST. SHOWERS ARE LIKELY ON SATURDAY BUT WINDS ARE EXPECTED TO REMAIN BELOW SCA LEVELS DURING THE DAY. SCA CONDITIONS COULD RETURN AT LEAST OVER THE LOWER BAY/TIDAL POTOMAC LATE SATURDAY NIGHT. POST TROF CAA SURGE COMBINED W/ SLGTLY BETTER DAYTIME MIXING MAY LEAD TO CONTD SCA CONCERNS OVER PORTIONS OF THE WATERS SUN MRNG. OTRW...HIPRES OVER WATERS INTO MON.
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&& .TIDES/COASTAL FLOODING...
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COLD FRONT CROSSED AREA LAST NIGHT...FINALLY BRINGING THE SUPPORT TO DRIVE EXCESS WATER OUT OF THE ESTUARY. ANOMALIES HV SINCE DROPPED... IN SOME CASES MARKEDLY. THIS EFFECT NOT YET AS STRONG FOR THE LOWER POTOMAC OR MID BAY...BUT IT SEEMS TO BE ENOUGH. SOLOMONS AND LEWISETTA ARE NEAR HIGH TIDE...AND ITS UNDER CRITICAL THRESHOLDS. THUS...BELIEVE WE WILL NOT REQUIRE ADDITIONAL ADVISORIES AT THIS TIME.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL NOON EDT TODAY FOR ANZ531>534-537- 539>541-543. SMALL CRAFT ADVISORY UNTIL 6 AM EDT EARLY THIS MORNING FOR ANZ530-535-536-538-542.
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&& $$ SYNOPSIS...HTS NEAR TERM...KRW SHORT TERM...KRW LONG TERM...HTS AVIATION...HTS/KRW MARINE...HTS/KRW TIDES/COASTAL FLOODING...HTS

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