Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 301937 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 337 PM EDT MON MAR 30 2015 .SYNOPSIS...
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DRY NORTHWEST WINDS WILL CONTINUE BEHIND A COLD FRONT INTO THE LATE EVENING HOURS...WHILE ANOTHER POTENT UPPER LEVEL LOW QUICKLY APPROACHES FROM THE GREAT LAKES REGION. THIS FEATURE WILL MOVE ACROSS THE REGION ON TUESDAY...REINFORCING THE DRY AND WINDY CONDITIONS. HIGH PRESSURE WILL BRIEFLY BUILD IN DURING THE MIDDLE OF THE WEEK...WITH ANOTHER COLD FRONT EXPECTED BY THE END OF THE WORK WEEK.
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&& .NEAR TERM /THROUGH TUESDAY/...
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A COMPLEX UPPER LEVEL TROUGH NOW MOVING OFF THE COAST AND BEHIND THE EXITING COLD FRONT...WNW BREEZES IN THE 20-30KT RANGE CONTINUE THRU THE LATE AFTN HRS. MAX TEMPS W/ THE CLEARING SKIES WILL PEAK IN THE 50S AND L60S. CONDITIONS WILL QUIET DOWN OVERNIGHT W/ CLEAR SKIES AND LIGHT WINDS. LOWS WILL DROP BACK INTO THE 30S FROM THE DRIER AIRMASS THAT HAS BEEN OVERCOMING THE AREA IN RECENT HRS. AN INITIALLY WEAK AND MINOR UPPER WAVE OVER THE WRN GREAT LAKES/NRN PLAINS WILL BECOME A POTENT AND TIGHTLY- WOUND VORT LOBE THAT WILL SLIDE DIRECTLY OVER THE MID-ATLC REGION ON TUE. MUCH OF THE PRECIP AND GUSTY WINDS WILL BE TIGHTLY PACKED NEAR THE SFC FEATURE. STARTING OFF THE DAY...IT WILL SEEM PRETTY CALM ACROSS THE REGION W/ SOME MID CLOUD DECKS COMING IN FROM THE NW. TOWARD THE MID MRNG HRS...WINDS WILL KICK UP OUT OF THE SW AND QUICKLY START TO GUST IN THE 20-30KT RANGE...W/ HIGHER GUSTS OVER THE TERRAIN OF THE SW/BLUE RIDGE MTNS. LOOKING THRU SOME OF THE HI-RES MODELS IN THE NEAR TERM...THE PRECIP W/ THE DEVELOPING SYSTEM TMRW WILL BE CLOSE TO THE LOW WHICH LOOKS TO TRACK ACROSS THE MASON-DIXON LINE. THE HIGHEST EXPECTED QPF IS ACROSS NRN/NE MD...AND THE HEAVIEST ALONG W/ THE EVENTUAL COLD FRONT LATE AFTN/EVE TIME. DENSE OVERCAST ASSOCIATED W/ THIS ACTIVITY NEAR THE SFC LOW OVER THE NRN HALF OF THE CWA BUT SKIES WILL BE LESS CLOUDY OVER THE SWRN ZONES AND WINDS WILL GUST OUT OF THE SW...BUILDING THE FIRE WX CONCERNS FOR THE AREAS SURROUNDING THE BLUE RIDGE/FOOTHILLS AND SHEN VLY. SEE FIRE WX SECTION BELOW.
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&& .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
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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.
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&& .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
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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.
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&& .AVIATION /19Z MONDAY THROUGH SATURDAY/...
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THE DENSE 5-8KFT CLOUD DECK HAS DISPERSED TO A FEW/SCT BATCH OVER MUCH OF THE AREA. SKIES WILL CLEAR OUT CLOSER TO SUNSET...AS WELL AS THE GUSTY SFC CONDS. WINDS WILL PEAK W/ GUSTS IN THE 25-30KT RANGE BEFORE 00Z...THEN SUBSIDE AFTERWARD. WINDS WILL PICK UP OUT OF THE SW POST DAWN TUE...GUSTS WILL QUICKLY START WELL INTO THE 20-30KT RANGE ALONG W/ A COLD FRONT AND SOME SCATTERED SHOWERS TMRW AFTN. RAIN/SHOWERS WILL END FROM WEST TO EAST BY TUESDAY NIGHT. VFR CONDITIONS WILL RETURN TO THE TERMINALS BY 06Z AND PERSIST 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.
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&& .MARINE...
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SCA REMAINS REMAINS IN EFFECT ACROSS BAY/TP THRU MID-EVE. WNW WINDS WILL CONTINUE TO GUST IN THE 20-30KT RANGE W/ ONLY A FEW NEAR 30KT GUSTS EXPECTED OVER THE NEXT FEW HRS. WINDS DIMINISH LATE TONIGHT BUT INCREASE QUICKLY TUE MRNG POST DAWN...WELL INTO SCA RANGE BUT LATE MRNG. HOWEVER...A FAST-MOVING AND POTENT UPPER LOW WILL SLIDE THRU THE REGION TMRW...SPREADING LOW END GALE GUSTS AHEAD OF A COLD FRONT. GALES MAY ALSO BE PRESENT W/ RAIN SHOWERS SO A GALE WARNING IS IN EFFECT FOR THE MIDDAY HRS...SCA CONDS WILL CONTINUE INTO THE LATE NIGHT HRS OVER MUCH OF THE WATERS. SMALL CRAFT CONDITIONS LIKELY ON THE MIDDLE AND LOWER BAY AND LOWER TIDAL POTOMAC TUESDAY NIGHT. 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.
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&& .FIRE WEATHER...
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A COUPLE OF QUICK-MOVING LOW PRESSURE SYSTEMS W/ DRY AIR AND BREEZY CONDS - TODAY AND AGAIN ANOTHER TMRW - WILL SET UP PARTS OF THE AREA FOR ENHANCED FIRE WX CONCERNS. A DAY OF BREEZY NW WINDS TODAY AND GUSTY SW WINDS ON TUE WILL HELP DRY OUT FUEL MOISTURES OVER THE SW PORTION OF THE AREA - THE LOWER NRN SHEN VLY/N CNTL VA PIEDMONT. MUCH OF THE PRECIP IS EXPECTED TO STAY NORTH OF THESE AREAS AND GUSTY WINDS DROP RH VALUES DOWN INTO THE 20-30 PERCENT RANGE. STILL COORDINATING POSSIBLE FIRE WX HEADLINES FOR TUE AFTN/EVE.
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&& .TIDES/COASTAL FLOODING...
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WATER LEVELS STILL HOVERING IN THE 1-1.5` ABOVE NORMS RANGE AND ANNAPOLIS HAS PEAKED JUST ABOVE 2` AT HIGH TIDE. HOWEVER...WINDS HAVE SWITCHED TO WSW AND NW IN SOME CASES AT FAIRLY BREEZY WHICH IS BEGINNING TO TAKE EFFECT ON WATER LEVELS...STARTING THE GRADUAL DECREASE BACK TOWARD 1` ABOVE LEVELS AND LOWER. THESE STRONGER WINDS WILL GRADUALLY SUBSIDE LATER TONIGHT AND ANOTHER SURGE OF SWLY WINDS WILL START UP ON TUE MRNG. THIS MAY BEGIN TO PICK UP ANOMALIES AND INCREASE THEM TO SIMILAR OR HIGHER LEVELS INTO THE AFTN HRS ON TUE...BEFORE ANOTHER COLD FRONT MOVES THRU W/ YET ANOTHER SURGE OF STRONG NW WINDS TO TAKE LEVELS BACK DOWN AGAIN.
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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 8 PM EDT THIS EVENING FOR ANZ530>543. SMALL CRAFT ADVISORY FROM 6 PM TUESDAY TO MIDNIGHT EDT TUESDAY NIGHT FOR ANZ530-531-535-536-538-539. GALE WARNING FROM 11 AM TO 6 PM EDT TUESDAY FOR ANZ530>543. SMALL CRAFT ADVISORY FROM 6 PM TUESDAY TO 6 AM EDT WEDNESDAY FOR ANZ532>534-537-540>543.
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&& $$ SYNOPSIS...GMS NEAR TERM...GMS SHORT TERM...KRW LONG TERM...IR AVIATION...GMS/KRW/IR MARINE...GMS/KRW/IR FIRE WEATHER...GMS TIDES/COASTAL FLOODING...GMS

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