Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 310759 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 359 AM EDT TUE MAR 31 2015 .SYNOPSIS...
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HIGH PRESSURE WILL SLIDE TO THE SOUTH OF THE AREA TODAY. LOW PRESSURE AND A TRAILING COLD FRONT WILL MOVE THROUGH THE REGION THIS AFTERNOON AND EARLY EVENING. HIGH PRESSURE WILL THEN BUILD THROUGH WEDNESDAY BEFORE BECOMING A BERMUDA HIGH THURSDAY. ANOTHER COLD FRONT IS EXPECTED TO CROSS THE AREA FRIDAY INTO SATURDAY.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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LOW PRESSURE IS LOCATED NEAR CHICAGO EARLY THIS MORNING. THE LOW WILL CONTINUE TO TRACK QUICKLY TOWARDS THE SOUTHEAST...ACROSS OHIO AND WESTERN WV THROUGH THE MORNING HOURS AND ARRIVE IN EASTERN WV AND WESTERN MD BY EARLY AFTERNOON. SHOWERS AHEAD OF THE FRONT STILL FCST TO ARRIVE NEAR THE MASON DIXON LINE EITHER LATE MORNING OR EARLY AFTERNOON...AND THEN ACROSS THE AREA THROUGH MOST OF THE AFTERNOON. BEST DYNAMICS CONTINUE TO BE FCST NEAR THE LOW ITSELF...SO HIGHEST POPS WILL BE ACROSS THE NORTHERN AND EASTERN PORTIONS OF THE FORECAST AREA. SOUNDINGS INDICATE JUST ENOUGH INSTABILITY FOR A FEW POTENTIAL THUNDERSTORMS LATE THIS AFTN. GUSTY WINDS ALSO EXPECTED THIS AFTERNOON WITH A STRONG 700-850MB JET STREAM MOVING THROUGH AND GOOD MIXING. AFTER COLLABORATION WITH NEIGHBORING OFFICES...NOT ENOUGH CONFIDENCE TO ISSUE A WIND ADVISORY AT THIS TIME...BUT WILL CONTINUE TO MONITOR. HIGH TEMPS FORECAST SLIGHTLY HIGHER THAN MOS GUIDANCE. CENTRAL VA AND THE PIEDMONT WILL BE THE WARMEST WHERE THERE WILL BE LESS CLOUD COVER AND MORE TIME FOR HEATING AHEAD OF ANY RAIN...WITH TEMPS IN THE UPPER 60S TO LOW 70S. COOLER NEAR THE MASON DIXON LINE...WITH HIGHS IN THE UPPER 50S. 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. MIN TEMPS WILL RANGE FROM THE LOW 30S IN THE MOUNTAINS TO THE LOWER 40S IN DOWNTOWN WASHINGTON AND BALTIMORE.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
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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. MIN TEMPS WILL RANGE FROM THE LOW 30S IN THE MOUNTAINS TO THE LOWER 40S IN DOWNTOWN WASHINGTON AND BALTIMORE. HIGH PRESSURE WILL BUILD INTO THE MIDDLE ATLANTIC REGION ON WEDNESDAY. SUNNY AND COOLER CONDITIONS WITH HIGHS IN THE 50S TO LOWER 60S CAN BE EXPECTED WEDNESDAY.
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&& .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
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HIGH PRESSURE SHIFTS OFFSHORE WEDNESDAY EVENING...BECOMING A BERMUDA HIGH THURSDAY. UPR RIDGE AXIS SHIFTS EAST ACROSS THE MID-ATLANTIC WEDNESDAY EVENING INTO THURSDAY MORNING. RETURN FLOW WEDNESDAY NIGHT AND THURSDAY SLOWLY RETURNS MOISTURE TO THE AREA. PVA AHEAD OF THE NEXT TROUGH ALLOWS CHANCE POPS LATE THURSDAY. WARMING TREND THURSDAY AND FRIDAY AHEAD OF THE NEXT COLD FRONT. WITH DRY AND SUNNY CONDITIONS LASTING INTO THE AFTERNOON HOURS AND 10C 850MB TEMPS CROSSING THE AREA...THURSDAY MAY BE WARMEST DAY OF THE WEEK. THIS IS PARTICULARLY THE CASE IF THE 00Z GFS IS ANYWHERE CLOSE TO BEING RIGHT WITH A MORE PROGRESSIVE COLD FRONT. MAX TEMPS THURSDAY LOW TO MID 70S FOR MUCH OF THE CWA...LOW 60S ON WRN SHORE OF BAY. HUMID FRIDAY WITH AREAS S/E OF DC WARMEST (MID 70S) AS CLOUDS MOVE IN AHEAD OF COLD FRONT WITH UPR 60S/LOW 70S REST OF THE CWA. UPPER PATTERN BECOMES MORE ZONAL FRIDAY INTO THE WEEKEND WITH LOW PRESSURE MOVING EAST FROM CO...LIFTING NE ALONG THE CENTRAL APPALACHIANS. BERMUDA HIGH AND THIS LOW OPENS THE GULF. 1.2 INCH PWATS PROGGED BY 00Z GFS WHICH IS NEAR THE MAX FOR EARLY APRIL. LATER SHIFTS COULD PROBABLE ADD SOME HEAVY RAIN WORDING FOR TIMEFRAME IMMEDIATELY AHEAD OF THE COLD FRONT. HOPEFULLY GREATER CONSENSUS ON CDFROPA OCCURS. CURRENT THOUGHT IS CDFROPA LATE FRIDAY AFTERNOON THROUGH FRIDAY NIGHT. BELOW NORMAL TEMPERATURES ON TAP FOR SATURDAY IN WAKE OF COLD FRONT. WILL NEED TO MONITOR BROAD NRN STREAM TROUGH DIPPING INTO THE AREA SUNDAY.
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&& .AVIATION /08Z TUESDAY THROUGH SATURDAY/...
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VFR CONDITIONS TUESDAY MORNING. SHOWERS WILL MOVE THROUGH THE REGION DURING THE AFTERNOON...WITH POTENTIAL VSBY REDUCTIONS AND MVFR CIGS. ISOLATED TSTMS POSSIBLE LATE IN THE AFTN. GUSTY SOUTHWEST WINDS WILL DEVELOP LATE IN THE MORNING AND CONTINUE INTO THE AFTERNOON. GUSTS AROUND 25 TO 30 KNOTS ARE EXPECTED. 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 WEDNESDAY WITH NW WINDS 5-10KT. HIGH PRESSURE SHIFTS OFFSHORE WEDNESDAY EVENING AND BECOMES A BERMUDA HIGH THURSDAY. SLY FLOW UNTIL A COLD FRONT WHICH IS LIKELY TO CROSS FRIDAY NIGHT. POSSIBLE HEAVY RAIN AHEAD OF THAT COLD FRONT FRIDAY EVENING.
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&& .MARINE...
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POTENT LOW PRESSURE WILL MOVE TOWARD THE REGION THIS AFTERNOON BEFORE PASSING THROUGH THE WATERS LATE AFTERNOON OR EARLY EVENING.. GUSTY SOUTHWEST WINDS ARE EXPECTED TO DEVELOP AHEAD OF THIS SYSTEM BY LATE MORNING. A GALE WARNING IS IN EFFECT FOR THE WATERS LATE MORNING THROUGH THE AFTERNOON. 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 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. SCA EXPECTED ALL WATERS THURSDAY INTO FRIDAY IN BROAD RETURN FLOW AS A BERMUDA HIGH SETS UP AND A COLD FRONT APPROACHES. COLD FRONTAL PASSAGE LIKELY FRIDAY NIGHT. EXPECT HIGH END SCA/POSSIBLE GALE IN POST FROPA NWLY FLOW LATE FRIDAY NIGHT AND SATURDAY.
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&& .FIRE WEATHER...
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A RED FLAG WARNING HAS BEEN ISSUED FOR SEVERAL VIRGINIA COUNTIES IN THE HIGHLANDS...SHENANDOAH VALLEY...BLUE RIDGE AND CENTRAL FOOTHILLS. SUSTAINED WIND ARE EXPECTED AROUND 20 MPH WITH HIGHER GUSTS...AND LOWEST RH WILL DROP BELOW 30 PERCENT THIS AFTERNOON. FUEL MOISTURE IS BELOW REQUIRED THRESHOLDS IN THIS AREA. FURTHER EAST ALONG THE I-95 CORRIDOR AND SOUTHERN MD...FUEL MOISTURE INCREASES QUICKLY ABOVE 9 PERCENT...SO THE WATCH HAS BEEN DROPPED. AN ELEVATED RISK CONTINUES HOWEVER DUE TO GUSTY WINDS AND LOW RH. ANY RAIN THIS AFTERNOON WILL DIMINISH THE THREAT...SO THE WARNING MAY BE ABLE TO EXPIRE EARLY IN SOME LOCATIONS. OTHERWISE THE THREAT WILL DIMINISH BY THIS EVENING WITH DIURNALLY DECREASING RH.
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&& .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...
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DC...NONE. MD...NONE. VA...RED FLAG WARNING FROM 11 AM THIS MORNING TO 6 PM EDT THIS EVENING FOR VAZ025>027-029-030-036>040-050-051-501-502- 504-507-508. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EDT WEDNESDAY FOR ANZ532>534-537-540>543. GALE WARNING FROM 11 AM THIS MORNING TO 6 PM EDT THIS EVENING FOR ANZ530>543. SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT EDT TONIGHT FOR ANZ530-531-535-536-538-539.
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&& $$ SYNOPSIS...KS NEAR TERM...KS SHORT TERM...KS LONG TERM... AVIATION...BAJ/KS MARINE...BAJ/KS FIRE WEATHER... TIDES/COASTAL FLOODING...

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