Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 310152 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 952 PM EDT MON MAR 30 2015 .SYNOPSIS... HIGH PRESSURE OVER THE TENNESSEE VALLEY WILL CONTROL THE WEATHER PATTERN FOR TONIGHT. POTENT LOW PRESSURE WILL MOVE TOWARD THE MASON-DIXON LINE TUESDAY AND THE COLD FRONT ASSOCIATED WITH THIS SYSTEM IS EXPECTED TO PASS THROUGH OUR AREA LATE TUESDAY AFTERNOON AND EVENING. HIGH PRESSURE WILL BRIEFLY BUILD IN DURING THE MIDDLE OF THE WEEK...WITH ANOTHER COLD FRONT EXPECTED BY THE END OF THE WORK WEEK. && .NEAR TERM /THROUGH TUESDAY NIGHT/... THE WEAK COLD FRONT THAT PASSED THROUGH THIS AFTERNOON WILL CONTINUE TO MOVE OFF TO THE EAST TONIGHT. A SURFACE RIDGE AXIS AROUND HIGH PRESSURE CENTERED OVER THE TENNESSEE VALLEY IS EXPECTED TO BUILD OVERHEAD LATE TONIGHT...ALLOWING FOR DRY CONDITIONS. THE GRADIENT MAY HOLD ON ENOUGH FOR A LIGHT WIND TO PERSIST...MINIMIZING THE POTENTIAL FOR RADIATIONAL COOLING. THEREFORE...THE MIN TEMP FORECASTS LEAN TOWARD THE WARMER GUIDANCE. A POTENT SHORTWAVE AND ITS ASSOCIATED LOW WILL TRACK THROUGH THE GREAT LAKES INTO OHIO LATE TONIGHT. THIS SYSTEM WILL DRIFT TOWARD THE MASON-DIXON LINE BY MIDDAY TUESDAY BEFORE MOVING OFF TO THE EAST TUESDAY AFTERNOON. THE COLD FRONT ASSOCIATED WITH THE LOW IS EXPECTED TO PASS THROUGH OUR AREA LATE TUESDAY AFTERNOON AND EVENING. THERE WILL BE SOME SHOWERS THROUGH MIDDAY TUESDAY ACROSS EXTREME NORTHERN PORTIONS OF OUR CWA...CLOSER TO THE LOW. HOWEVER...MUCH OF THE AREA WILL TURN OUT DRY...WINDY AND WARM WITH MAX TEMPS REACHING THE 60S AND EVEN THE LOWER 70S ACROSS PORTIONS OF CENTRAL VIRGINIA. SHOWERS ALONG AND AHEAD OF THE COLD FRONT WILL SPREAD SOUTH INTO NORTHERN VIRGINIA AS WELL AS THE WASHINGTON AND BALTIMORE METROPOLITAN AREAS LATER TUESDAY AFTERNOON BEFORE EVENTUALLY MOVING THROUGH SOUTHERN MARYLAND AND THE VIRGINIA PIEDMONT TUESDAY EVENING. RAINFALL AMOUNTS SHOULD BE LIGHT ACROSS MOST AREAS...AVERAGING LESS THAN ONE-QUARTER OF AN INCH. HOWEVER...THERE WILL BE SOME INSTABILITY AHEAD OF THE COLD FRONT AND THIS MAY LEAD TO A FEW HEAVIER SHOWERS AND PERHAPS EVEN A COUPLE THUNDERSTORMS. DESPITE SKINNY CAPE IN THE FORECAST SOUNDINGS...THERE WILL BE PLENTY OF COLD AIR ALOFT AND LOW-LEVEL DRY AIR WITH AN INVERTED V SIGNATURE IN THE SOUNDINGS FOR SMALL HAIL AND GUSTY WINDS TO ACCOMPANY SHOWERS AND ISOLATED THUNDERSTORMS THAT DO DEVELOP. THE COLD FRONT WILL BE TO THE SOUTH OF OUR CWA BY MIDNIGHT. DRIER AND CHILLIER CONDITIONS ARE EXPECTED BEHIND THE FRONT WITH A NORTHWEST FLOW OVERNIGHT TUESDAY. MIN TEMPS WILL RANGE FROM THE 20S IN THE MOUNTAINS TO THE MID AND UPPER 30S IN WASHINGTON AND BALTIMORE. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY/... FAST-MOVING CLIPPER SYSTEM WILL MOVE AWAY FROM THE MIDDLE ATLANTIC REGION TUESDAY NIGHT. A COOLER AIRMASS WILL BUILD IN BEHIND THE LOW PRESSURE SYSTEM AND TEMPERATURES WILL FALL BACK INTO THE 30S IN MOST LOCALES WITH 20S OVER THE WEST. NORTHWEST WINDS WILL ALSO GRADUALLY DIMINISH OVERNIGHT. HIGH PRESSURE WILL BUILD INTO THE MIDDLE ATLANTIC REGION ON WEDNESDAY AND PERSIST INTO THURSDAY. SUNNY AND COOLER CONDITIONS WITH HIGHS IN THE 50S TO LOWER 60S CAN BE EXPECTED WEDNESDAY. AS THE HIGH SHIFTS TO THE EAST ON THURSDAY...WINDS WILL SHIFT INTO THE SOUTH AND SOUTHWEST WHICH WILL PUMP MILDER AIR INTO THE FORECAST AREA. TEMPERATURES WILL LIKELY MODERATE INTO THE 60S TO THE LOWER 70S AREA WIDE...PERHAPS A FEW MIDDLE 70 DEGREE READINGS OVER CENTRAL VA. SHOWER CHANCES WILL BEGIN TO INCREASE FROM WEST TO EAST LATER THURSDAY...AHEAD OF THE NEXT COLD FRONT AND AREA OF LOW PRESSURE. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... HIGH PRESSURE CONTINUES TO MOVE OFFSHORE WHILE COLD FRONT APPROACHES THURS NIGHT STARTING A POSSIBLE EXTENDED RAIN EVENT. COLD FRONT MOVES ACROSS THE CWA ON FRI. PRECIP MOVES FROM WEST TO EAST AND LASTS INTO SAT AS A LOW PRESSURE BRINGS MOISTURE FROM THE GULF FRI INTO SAT AFTERNOON. HIGH PRESSURE BUILDS IN ON SAT NIGHT. WEAK COLD FRONT MAY BRING SOME PRECIP SUN AFTERNOON INTO NIGHT. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... WINDS WILL BE LIGHT TONIGHT AND VFR CONDITIONS ARE EXPECTED. GUSTY SOUTHWEST WINDS WILL DEVELOP LATE TUESDAY MORNING INTO TUESDAY AFTERNOON. GUSTS AROUND 25 TO 30 KNOTS ARE EXPECTED. A FEW SHOWERS WILL OVERSPREAD THE TERMINALS LATE TUESDAY AFTERNOON INTO TUESDAY EVENING AS A COLD FRONT PASSES THROUGH. THERE MAY BE ENOUGH INSTABILITY FOR A COUPLE THUNDERSTORMS AS WELL. GUSTY WINDS AND SMALL HAIL ARE POSSIBLE IN HEAVIER SHOWERS OR THUNDERSTORMS DURING THIS TIME. A WIND SHIFT TO THE NORTHWEST IS EXPECTED BEHIND THE FRONT WITH GUSTS AROUND 20 KNOTS. VFR CONDITIONS AND DRY CONDITIONS WILL PERSIST OVERNIGHT. VFR CONDITIONS WILL RETURN CONTINUE THROUGH THURSDAY EVENING. THE NEXT COLD FRONT AND AREA OF LOW PRESSURE WILL APPROACH FROM THE WEST LATER THURSDAY NIGHT BRINGING A CHANCE FOR SHOWERS. COLD FRONT APPROACHES THURS NIGHT AND MOVES ACROSS ON FRI... BRINGING RAIN THROUGH SAT. WINDY CONDITIONS ARE EXPECTED BEHIND COLD FRONT. && .MARINE... WINDS WILL DIMINISH BELOW SCA CRITERIA TONIGHT AS A SURFACE RIDGE AXIS BUILDS OVER THE WATERS. POTENT LOW PRESSURE WILL MOVE TOWARD THE PENNSYLVANIA-MARYLAND BORDER TUESDAY AFTERNOON BEFORE PASSING THROUGH THE NORTHERN WATERS LATE TUESDAY AFTERNOON. THE COLD FRONT ASSOCIATED WITH THE LOW WILL PASS THROUGH THE REST OF THE WATERS TUESDAY EVENING. GUSTY SOUTHWEST WINDS ARE EXPECTED TO DEVELOP AHEAD OF THIS SYSTEM LATE TUESDAY MORNING INTO TUESDAY AFTERNOON. A GALE WARNING IS IN EFFECT FOR THE WATERS DURING THIS TIME. HOWEVER...IT WILL BE MARGINAL AND MOST GUSTS MAY END UP BEING HIGH-END SCA CRITERIA DUE TO THE RELATIVELY COOLER WATERS. HOWEVER...THERE WILL BE A FEW SHOWERS AND PERHAPS EVEN A COUPLE THUNDERSTORMS THAT PASS THROUGH THE WATERS AHEAD OF THE COLD FRONT LATE TUESDAY AFTERNOON AND EVENING. DESPITE LIMITED INSTABILITY...THERE IS THE POTENTIAL FOR GUSTY WINDS AND SMALL HAIL IN HEAVIER SHOWERS AND THUNDERSTORMS DURING THIS TIME. THE COLD FRONT WILL MOVE SOUTH OF THE WATERS LATE TUESDAY NIGHT AND NORTHWEST WINDS ARE EXPECTED BEHIND THE BOUNDARY. A SMALL CRAFT ADVISORY IS IN EFFECT FOR ALL OF THE WATERS TUESDAY EVENING...AND FOR THE MIDDLE PORTION OF THE BAY AND LOWER TIDAL POTOMAC RIVER OVERNIGHT TUESDAY. WINDS WILL FALL BELOW SCA LEVELS ON WEDNESDAY BUT WILL INCREASE OUT OF THE SOUTH ON THURSDAY. SOUTHERLY CHANNELING WILL BE POSSIBLE AND WINDS COULD REACH SCA. SCA LIKELY FRI NIGHT INTO SAT BEHIND COLD AS WINDY CONDITIONS DEVELOP. && .FIRE WEATHER... GUSTY WINDS HAVE DIMINISHED THIS EVENING. WINDS WILL REMAIN LIGHT ACROSS MOST AREAS OVERNIGHT. HOWEVER...LOW PRESSURE AND ITS ASSOCIATED COLD FRONT ARE EXPECTED TO PASS THROUGH LATE TUESDAY AFTERNOON AND EVENING. THE PRESSURE GRADIENT WILL STRENGTHEN AHEAD OF THE FRONT...CAUSING GUSTY SOUTHWEST WINDS AND LOW RELATIVE HUMIDITY. THE COMBINATION OF THE GUSTY WINDS...LOW HUMIDITY AND LOW FUEL MOISTURE DUE TO RECENT DRY CONDITIONS WILL HAVE THE POTENTIAL TO ENHANCE THE THREAT FOR THE SPREAD OF WILDFIRES. THE BEST CHANCE FOR THE CRITICAL FIRE WEATHER CONDITIONS TO DEVELOP WILL BE ACROSS CENTRAL VIRGINIA INTO SOUTHERN MARYLAND. A FIRE WEATHER WATCH IS IN EFFECT FOR THESE AREAS LATE TUESDAY MORNING THROUGH TUESDAY AFTERNOON. FURTHER NORTH...THERE MAY BE A PERIOD OF GUSTY WINDS BUT THE RH VALUES ARE FORECAST TO BE HIGHER AND THERE MAY EVEN BE SOME RAIN THAT MOVES IN TUESDAY AFTERNOON. HIGH PRESSURE WILL BRING DRY CONDITIONS AND LIGHTER WINDS TUESDAY NIGHT THROUGH WEDNESDAY. GUSTY WINDS ARE POSSIBLE THURSDAY...BUT ATMOSPHERIC MOISTURE WILL BE HIGHER DUE TO THE SOUTHERLY FLOW THAT IS EXPECTED. && .TIDES/COASTAL FLOODING... TIDAL ANOMALIES HAVE DECREASED DUE TO THE OFFSHORE FLOW. ANOTHER SURGE OF SWLY WINDS WILL START UP ON TUE MRNG AND AFTERNOON AHEAD OF A COLD FRONT. ANOMALIES MAY QUICKLY INCREASE DURING THIS TIME AND WATER LEVELS MAY APPROACH MINOR FLOODING THRESHOLDS DURING THE HIGH TIDE CYCLE TUESDAY AFTERNOON INTO TUESDAY EVENING. GUSTY NORTHWEST WINDS WILL CAUSE ANOMALIES TO RAPIDLY FALL BEHIND A COLD FRONT LATER TUESDAY NIGHT. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...FIRE WEATHER WATCH FROM TUESDAY MORNING THROUGH TUESDAY AFTERNOON FOR MDZ016>018. VA...FIRE WEATHER WATCH FROM TUESDAY MORNING THROUGH TUESDAY AFTERNOON FOR VAZ025>027-029-030-036>040-050>052-055>057- 501-502-504-507-508. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 PM TUESDAY TO 6 AM EDT WEDNESDAY FOR ANZ532>534-537-540>543. GALE WARNING FROM 11 AM TO 6 PM EDT TUESDAY FOR ANZ530>543. SMALL CRAFT ADVISORY FROM 6 PM TUESDAY TO MIDNIGHT EDT TUESDAY NIGHT FOR ANZ530-531-535-536-538-539. && $$ SYNOPSIS...GMS NEAR TERM...BJL/GMS SHORT TERM...KRW LONG TERM...IR AVIATION...BJL/GMS/IR MARINE...BJL/GMS/IR FIRE WEATHER...BJL TIDES/COASTAL FLOODING...BJL/GMS

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