Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 170726 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 326 AM EDT WED SEP 17 2014 .SYNOPSIS...
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HIGH PRESSURE WILL BUILD OVER THE REGION THROUGH TONIGHT. A WEAK COLD FRONT WILL PASS THROUGH THE AREA THURSDAY. HIGH PRESSURE WILL RETURN FOR FRIDAY AND SATURDAY BEFORE MOVING OFF THE COAST SUNDAY.
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&& .NEAR TERM /THROUGH THURSDAY/...
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A LARGE AREA OF HIGH PRESSURE IS CENTERED ACROSS THE MID-WEST AND EXTENDS ACROSS THE MID-ATLANTIC EARLY THIS MORNING. A COLD FRONT IS LOCATED ACROSS THE CAROLINAS. CLEAR AND NEARLY CALM CONDITIONS HAVE LED TO TEMPS DROPPING INTO THE 50S AND NEAR 40 ACROSS THE ALLEGHENY FRONT. LOW CLOUDS WILL CONTINUE TO MOVE ACROSS THE VA HIGHLANDS AND SHENANDOAH VALLEY AS LOW LEVEL MOISTURE STAYS UNDER THE NOCTURNAL INVERSION. A FEW CLOUDS MAY CLIP THE PIEDMONT THIS MORNING AS CLOUD DEBRIS FROM THE ACTIVITY ACROSS THE CAROLINAS MOVES NEAR THE AREA. HIGH PRESSURE WILL CONTINUE ACROSS THE AREA TODAY AND FCST MAX TEMPS WILL REACH THE 60S IN THE MTNS TO THE LOW TO MID 70S EAST OF THE BLUE RIDGE. A BROAD UPPER LEVEL TROUGH WILL CONTINUE ACROSS THE NORTHEAST CONUS TONIGHT AND A WEAK DISTURBANCE WILL APPROACH THE POTOMAC HIGHLANDS THIS EVENING. CLOUDS SHOULD INCREASE FROM WEST TO EAST TONIGHT AND INTO THURSDAY MORNING. ANOTHER STRONG AREA OF HIGH PRESSURE WILL APPROACH THE NRN GREAT LAKES LATE TONIGHT. A COLD FRONT AHEAD OF THIS AIR MASS WILL MOVE THROUGH THE REGION THURSDAY. NRLY WINDS WILL INCREASE AS THE FRONT CROSSES BY THURSDAY EVENING. DRY CONDITIONS ARE EXPECTED DUE TO THE LACK OF UPPER LEVEL FORCING ALONG THE FRONT AND LACK OF MOISTURE.
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&& .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY/...
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BEHIND THE WEAK COLD FROPA THURSDAY NIGHT...A HIGH PRESSURE WEDGE BUILDS IN ACROSS THE MID-ATLANTIC EXTENDING FROM THE HIGH PRESSURE CENTER OVER NEW ENGLAND. LOW LEVEL FLOW VEERS AND BECOMES ONSHORE DOMINATE FOR FRIDAY. WHILE OVERALL AIRMASS REMAINS DRY...HAVE INCREASED CLOUD COVER MAINLY ACROSS THE MOUNTAINS WITH LOW LEVEL MOISTURE FEED AND UPSLOPE COMPONENT.
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&& .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
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AS UPPER FLOW TRANSITIONS FROM CYCLONIC TO ANTICYCLONIC OVERHEAD FOR SATURDAY AND SUNDAY...LOW LEVELS RESPONSE WITH INCREASING SOUTHERLY FLOW AND WARM AIR ADVECTION. TEMPERATURES ON SUNDAY SHOULD WARM INTO THE LOW TO MID 80S. TRAILING STRONGER COLD FRONT EXTENDING FROM GREAT LAKES LOW WILL THEN PUSH THROUGH THE REGION SUNDAY NIGHT THROUGH MONDAY...SLOWING FOR A BIT MONDAY AHEAD OF SECONDARY SHORT WAVE IN UPPER TROUGH. SHOULD SEE CONVECTIVE SHOWERS WITH THIS FRONT...HOWEVER WIDESPREAD HEAVIER RAIN DOES NOT LOOK LIKELY AT THIS TIME. AUTUMN-LIKE CONDITIONS ARE THEN EXPECTED INTO NEXT WEEK AS H85 TEMPS FALL INTO THE SINGLE DIGITS ABOVE ZERO CELSIUS. MID-ATLANTIC SITS IN TIGHTER PRESSURE GRADIENT WITH ONSHORE FLOW AS LARGE AREA OF HIGH PRESSURE BUILDS ACROSS THE GREAT LAKES REGION.
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&& .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
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HIGH PRESSURE WILL CONTINUE ACROSS THE TERMINALS TODAY. VFR CONDITIONS EXPECTED TODAY. CLOUDS WILL INCREASE FROM NW TO SE TONIGHT AS A COLD FRONT APPROACHES THE REGION. MVFR/IFR VSBYS POSSIBLE AT CHO EARLY THURSDAY MORNING. THE COLD FRONT WILL CROSS THE TERMINALS FROM WEST TO EAST THURSDAY. NRLY WINDS EXPECTED BEHIND THE FRONT. A HIGH PRESSURE WEDGE WILL BE IN PLACE FOR FRIDAY...AND WINDS WILL VEER SOUTHERLY FOR THE WEEKEND AHEAD OF AN APPROACHING COLD FRONT. THIS FRONT WILL BRING THE CHANCE OF SHOWERS WITH AREAS OF LOWER CIGS SUNDAY NIGHT AND MONDAY ACROSS THE REGION ALONG WITH A WIND SHIFT.
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&& .MARINE...
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HIGH PRESSURE WILL MOVE ACROSS THE WATERS TODAY AND TONIGHT. N-NE WINDS 10-15 KTS EXPECTED ACROSS THE WATERS THIS MORNING MAINLY SOUTH OF DRUM PT ON THE BAY AS A PRESSURE GRADIENT EXISTS AS HIGH PRSESURE APPROACHES THE AREA. WINDS WILL RELAX BY THIS AFTERNOON. A COLD FRONT WILL CROSS THE WATERS THURSDAY AFTERNOON/EVENING. NRLY WINDS BEHIND THE FRONT ARE EXPECTED. HIGH PRESSURE BUILDING ACROSS THE REGION FRIDAY WILL BRING ONSHORE WINDS AND POSSIBLE SCA CONDITIONS WITH HIGHER GUSTS ACROSS PORTIONS OF THE WATERS. A COLD FRONT WILL PUSH THROUGH THE REGION SUNDAY NIGHT AND MONDAY...BRINGING THE CHANCE OF SHOWERS AND GUSTY WINDS.
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&& .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...NONE. WV...NONE. MARINE...NONE. && $$ SYNOPSIS...HAS NEAR TERM...HAS SHORT TERM...AEB LONG TERM...AEB AVIATION...HAS/AEB MARINE...HAS/AEB

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