Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 310720 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 320 AM EDT FRI JUL 31 2015 .SYNOPSIS...
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HIGH PRESSURE WILL BUILD OVERHEAD THROUGH TONIGHT. A WEAK COLD FRONT WILL PASS THROUGH SATURDAY AND HIGH PRESSURE WILL RETURN FOR SUNDAY. A COLD FRONT WILL APPROACH THE AREA FROM THE NORTH EARLY NEXT WEEK. LOW PRESSURE WILL RIDE ALONG THE BOUNDARY...PASSING THROUGH OUR AREA WEDNESDAY NIGHT INTO THURSDAY BEFORE THE BOUNDARY SAGS TO OUR SOUTH LATE NEXT WEEK.
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&& .NEAR TERM /THROUGH SATURDAY/...
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DRIER AIR IS SLOWLY SEEPING ITS WAY INTO THE FORECAST AREA THIS MORNING...WITH THE COLD FRONT SOMEWHERE NEAR THE EASTERN EDGE OF THE FORECAST AREA. THE DEWPOINT DROP IS THE MAIN SIGNAL...DROPPING AROUND 10 DEGREES BEHIND THE FRONT. WITH DOWNSLOPING WESTERLY WINDS...A DRY DAY IS ON TAP TODAY. TEMPERATURES WILL BE FAIRLY SIMILAR TO YESTERDAY DESPITE BEING BEHIND AN IN-NAME-ONLY COLD FRONT SINCE THE DRIER AIR AND WESTERLY WINDS WILL COMBINE TO PROMOTE HEATING. CLEAR AND COOL TONIGHT WITH LOWS DROPPING INTO THE 50S IN MOST AREAS WEST OF THE BLUE RIDGE. 60S ALMOST EVERYWHERE ELSE. A REINFORCING IN-NAME-ONLY COLD FRONT WILL PUSH THROUGH THE REGION ON SATURDAY...BUT THERE IS SIMPLY NO TIME FOR RETURN FLOW...SO THE FROPA IS LIKELY TO BE DRY. WORTH NOTHING THAT OUR LOCAL WRF- NMM...AND THE OPERATIONAL NAM...DEVELOP SOME SHRA IN THE VIRGINIA PIEDMONT SATURDAY AFTERNOON. WHILE I CANNOT RULE THAT OUT...THE CHANCES SEEM TOO SMALL TO INCLUDE IN THE FORECAST AT THIS TIME. WILL KEEP IT DRY BUT WARM WITH HIGHS AROUND 90 IN THE URBAN CORRIDOR. GREAT WEEKEND FOR A MOUNTAIN GETAWAY...WHERE HIGHS WILL STAY IN THE 70S.
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&& .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
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HIGH PRESSURE WILL BUILD BUILD IN FROM THE WEST SATURDAY NIGHT THROUGH SUNDAY...BRINGING DRY CONDITIONS. A DOWNSLOPING WESTERLY FLOW WILL KEEP HUMIDITY DOWN DURING THIS TIME...BUT IT WILL TURN OUT TO BE A HOT AFTERNOON SUNDAY WITH MAX TEMPS IN THE UPPER 80S AND LOWER 90S ACROSS MOST LOCATIONS. HIGH PRESSURE WILL CONTINUE TO BRING DRY CONDITIONS FOR SUNDAY NIGHT.
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&& .LONG TERM /MONDAY THROUGH THURSDAY/...
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A LONGWAVE UPPER-LEVEL TROUGH WILL REMAIN OVER THE REGION FOR THE EARLY AND MIDDLE PORTIONS OF NEXT WEEK. MOST OF THE ENERGY ASSOCIATED WITH THE TROUGH WILL REMAIN TO OUR NORTH DURING THIS TIME. HIGH PRESSURE WILL MOVE OFF THE COAST MONDAY AND A SOUTHWEST FLOW WILL ALLOW FOR MORE HOT CONDITIONS...BUT HUMIDITY MAY BE DOWN A BIT WITH DEWPOINTS REMAINING IN THE 50S AND 60S. A COLD FRONT WILL APPROACH THE AREA MONDAY NIGHT THROUGH WEDNESDAY...BUT IT SHOULD REMAIN TO THE NORTH. THEREFORE...MORE HOT CONDITIONS ARE EXPECTED. A SHOWER OR THUNDERSTORM CANNOT BE RULED OUT DURING THIS TIME...BUT MOST AREAS WILL BE DRY. PERHAPS THERE WILL BE A BETTER CHANCE FOR A THUNDERSTORM ACROSS CENTRAL AND SOUTHERN AREAS WEDNESDAY AFTERNOON/EVENING...WHEN THE HUMIDITY WILL BE A BIT HIGHER DUE TO LESS OF A DOWNSLOPING WESTERLY FLOW. LOW PRESSURE WILL RIDE ALONG THE BOUNDARY...PASSING THROUGH THE AREA WEDNESDAY NIGHT OR THURSDAY. TIMING IS UNCERTAIN AT THIS TIME...BUT THERE WILL BE A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS WHEN THIS SYSTEM PASSES THROUGH. THE COLD FRONT WILL DROP TO OUR SOUTH LATE IN THE WEEK BEHIND THE DEPARTING WAVE OF LOW PRESSURE.
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&& .AVIATION /07Z FRIDAY THROUGH TUESDAY/...
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KCHO HAS BEEN BOUNCING AROUND IN LOWER CIGS/VSBY IN FOG EARLY THIS MORNING...BUT AS DRIER AIR CONTINUES TO FILTER IN...THIS IS NOT EXPECTED TO LAST MUCH LONGER. OTHERWISE...VFR THROUGH THE VALID TAF PERIOD. VFR CONDITIONS ARE EXPECTED SATURDAY NIGHT THROUGH MONDAY. THERE MAY BE A SHOWER OR THUNDERSTORM MONDAY NIGHT AND TUESDAY...BUT MOST OF THE TIME WILL BE DRY AND ANY CONVECTION WILL BE ISOLATED.
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&& .MARINE...
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LIGHT WINDS ARE EXPECTED THROUGH EARLY SATURDAY. A PUSH OF SLIGHTLY STRONGER WINDS MAY OCCUR BEHIND A COLD FRONT SATURDAY AFTERNOON...APPROACHING SCA CRITERIA. FOR NOW...CAPPED THE FORECAST AT 15 KTS. A COLD FRONT WILL APPROACH FROM THE NORTH MONDAY AND TUESDAY. THE GRADIENT MAY BE STRONG ENOUGH FOR SOUTHERLY WINDS TO CHANNEL UP THE BAY AND LOWER TIDAL POTOMAC RIVER MONDAY NIGHT INTO TUESDAY...CAUSING WIND GUSTS AROUND SCA CRITERIA. A SHOWER OR THUNDERSTORM IS POSSIBLE MONDAY NIGHT/TUESDAY...BUT MOST AREAS WILL BE DRY AND ANY CONVECTION WILL BE ISOLATED. AN ISOLATED SHOWER OR THUNDERSTORM IS POSSIBLE WEDNESDAY AS WELL...BUT THERE WILL BE A BETTER CHANCE FOR SHOWERS AND THUNDERSTORMS WEDNESDAY NIGHT OR THURSDAY AS A WAVE OF LOW PRESSURE PASSES THROUGH THE AREA.
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&& .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...BJL NEAR TERM...JCE SHORT TERM...BJL LONG TERM...BJL AVIATION...JCE/BJL MARINE...JCE/BJL

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