Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 230755 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 355 AM EDT WED APR 23 2014 .SYNOPSIS...
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HIGH PRESSURE WILL SLOWLY BUILD OVER THE AREA THROUGH THURSDAY. A COLD FRONT WILL PASS THROUGH THE AREA FRIDAY AND ANOTHER COLD FRONT IS EXPECTED TO MOVE THROUGH SATURDAY. HIGH PRESSURE WILL BUILD OVERHEAD SUNDAY AS THE COLD FRONT STALLS TO OUR SOUTH. WAVES OF LOW PRESSURE WILL DEVELOP ALONG THE STALLED BOUNDARY...BRINGING UNSETTLED CONDITIONS TO THE AREA NEXT WEEK.
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&& .NEAR TERM /THROUGH TONIGHT/...
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DRIER AND COOLER AIR BEING USHERED IN BEHIND THE COLD FRONT THAT MOVED THRU EARLIER IN THE OVERNIGHT. GUSTY WINDS SWEEPING ACROSS THE REGION...AS THEY WILL FOR MUCH OF THE DAY TODAY. A POTENT VORT LOBE SWINGING DOWN ACROSS THE MASON-DIXON LINE IN THE MID LEVELS. THIS FEATURE WILL BE MIXING-DOWN THE STRONGER WIND GUSTS IN THE COMING HRS...HELPING TO DROP TEMPS DOWN INTO THE M-U40S BY THE PREDAWN HRS WHICH IS ACTUALLY RIGHT AROUND SEASONAL AVG FOR OVERNIGHT LOWS. AS SKIES CLEAR OUT AND THE SUN COMES OUT IN THE COMING HRS...MORE OF THE HIGHER WIND GUSTS WILL SPREAD OUT ACROSS THE REGION. THE UPPER VORT WILL PUSH OFF THE COAST NEAR DAWN...W/ THE SUBSIDENCE REGION SETTING UP DIRECTLY OVER ERN MD AND TAPERING OFF INTO NRN VA. TEMPS WILL EVENTUALLY CLIMB BACK INTO THE L-M60S THIS AFTN...BUT WINDS IN THE 20-30MPH RANGE WILL KEEP AT LEAST SOME CHILL FACTOR IN THE AIR FOR MUCH OF THE DAY. SOME OF THE HIGHER GUSTS WILL PEAK NEAR 40MPH DURING THE EARLY-MID AFTN DURING PEAK HEATING. THE COMBINATION OF GUSTY WINDS...LOW RHS AND LOW FUEL MOISTURES WILL CREATE THE ELEVATED WILDFIRE DANGER TODAY - SO A RED FLAG WARNING HAS BEEN ISSUED FOR MUCH OF THE AREA DURING THE DAYTIME HRS TODAY. SEE FIRE WX SECTION BELOW. ONCE THE UPPER VORT COMPLETELY MOVES OFF THE COAST SLOWLY INTO THU MRNG...WINDS WILL DROP OFF OVER THE WRN HALF OF THE REGION. NERN MD WILL REMAIN THE SOME OF THE BREEZIER CONDITIONS LATE TONIGHT...SINCE THE RIBBON OF UPPER VORTICITY WILL STILL BE HANGING OUT OVER DELMARVA - VERY SLOWLY DRIFTING TOWARD THE COAST. A DAY`S WORTH OF DRY AIR WILL ALLOW TEMPS TO DROP BACK DOWN AGAIN INTO THE M-U30S FOR OVERNIGHT LOWS. A FEW AREAS OF THE CWA LIKE THE APLCNS AND SHEN VLY WILL SEE TEMPS HOVERING AROUND FREEZING.
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&& .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
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SURFACE HIGH PRESSURE WILL BUILD OVER THE REGION THURSDAY WHILE AN UPPER-LEVEL RIDGE MOVES OVERHEAD DURING THIS TIME. PLENTY OF SUBSIDENCE WILL ALLOW FOR DRY CONDITIONS ALONG WITH SUNSHINE. MAX TEMPS WILL BE NEAR CLIMO...RANGING FROM THE 50S IN THE MOUNTAINS TO THE MID AND UPPER 60S ACROSS MOST OTHER LOCATIONS. SOME AREAS ACROSS CENTRAL VIRGINIA AND THE VALLEYS OF EASTERN WEST VIRGINIA MAY REACH INTO THE 70S. THE SURFACE HIGH AND UPPER-LEVEL RIDGE AXIS WILL SLIDE TO THE EAST THURSDAY NIGHT AND A COLD FRONT WILL APPROACH FROM THE OHIO VALLEY. CLOUDS ASSOCIATED WITH THIS SYSTEM WILL OVERSPREAD THE AREA...BUT PRECIPITATION SHOULD HOLD OFF UNTIL FRIDAY. MIN TEMPS WILL RANGE FROM THE LOWER TO MIDDLE 40S ACROSS MOST LOCATIONS TO NEAR 50 IN DOWNTOWN WASHINGTON AND BALTIMORE.
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&& .LONG TERM /FRIDAY THROUGH TUESDAY/...
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A COLD FRONT WILL PASS THROUGH THE REGION FRIDAY...BRINGING A FEW SHOWERS WITH IT. AN ISOLATED THUNDERSTORM CANNOT BE RULED OUT...BUT INSTABILITY WILL BE LIMITED SO ANY SEVERE THREAT SHOULD REMAIN WELL TO OUR SOUTH. THE BOUNDARY WILL MOVE EAST FRIDAY NIGHT ALLOWING FOR DRY CONDITIONS...BUT ANOTHER COLD FRONT WILL PASS THROUGH THE REGION SATURDAY AFTERNOON. LITTLE MOISTURE WILL BE ASSOCIATED WITH THIS SO MOST AREAS WILL LIKELY REMAIN DRY. SATURDAY WILL TURN OUT MILD AHEAD OF THE BOUNDARY DUE TO A DOWNSLOPING WESTERLY FLOW AHEAD OF THE FRONT. CANADIAN HIGH PRESSURE WILL BUILD OVERHEAD SATURDAY NIGHT THROUGH SUNDAY BEHIND THE FRONT...BRINGING DRY AND COOLER CONDITIONS. CUTOFF LOW PRESSURE WILL TRACK THROUGH THE PLAINS INTO THE MIDWEST NEXT WEEK. A WARM FRONT WILL STALL OUT NEAR THE REGION DURING THIS TIME AND UNSETTLED CONDITIONS ARE POSSIBLE. CERTAINTY IN THE FORECAST REMAINS LOW AT THIS TIME.
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&& .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
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GUSTY WINDS THE MAIN ISSUE FOR THE DURATION OF THE CURRENT TAF PERIOD. MID-20KT RANGE GUSTS ALREADY HAVE BEEN SPREADING OVER THE AREA IN THE PAST COUPLE OF HRS...W/ A SOLID 12-OR-SO MORE HRS TO GO W/ THE STRONGER TIER OF WINDS. AFTER SUNRISE...GUSTS AOB 30KT WILL BEGIN SPREADING OVER THE AREA - ESPEC OVER NRN MD AND JUST INTO NRN VA...ALL OUT OF THE NW TODAY. WINDS WILL BEGIN TO DROP OFF TO 15-20KT LATER THIS EVE AFTER SUNSET BUT STAY BREEZY OVER THE I-95 CORRIDOR AND EAST FOR THE OVERNIGHT. LIGHT WINDS FOR THE AREA WEST OF THE BLUE RIDGE LATER TONIGHT. NORTHWEST WINDS WILL GUST AROUND 20 TO 25 KNOTS THURSDAY ACROSS THE EASTERN TERMINALS. WINDS WILL BE LIGHTER ACROSS KMRB AND KCHO. HIGH PRESSURE OVER THE TERMINALS THURSDAY EVENING WILL SHIFT EAST OVERNIGHT. A SOUTHERLY FLOW WILL DEVELOP AHEAD OF A COLD FRONT DURING THIS TIME. THE COLD FRONT WILL PASS THROUGH THE TERMINALS FRIDAY WITH A FEW SHOWERS LIKELY. ANOTHER COLD FRONT WILL PASS THROUGH SATURDAY AFTERNOON AND EVENING AND IT WILL STALL OUT JUST TO THE SOUTH FOR SUNDAY. VFR CONDITONS ARE EXPECTED DURING THIS TIME.
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&& .MARINE...
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LOCALIZED GUSTY WINDS IN THE HIGHER-END SCA CRITERIA RANGE ARE APPEARING OVER THE WATER...MAINLY OVER THE NRN MD BAY OVERNIGHT. MORE MARGINAL GUSTS EXIST OVER THE REST OF THE BAY/TP RVR. WINDS BEHIND A COLD FRONT HAVE INCREASED OVER THE PAST FEW HRS. ONCE THE SUN RISES IN A FEW HRS...HIGHER WINDS WILL SPREAD ACROSS THE ENTIRETY OVER THE MD BAY AND TP RVR AND GALE GUSTS ARE EXPECTED TO APPEAR FOR MUCH OF THE DAYTIME HRS. HEADING INTO THE LATE EVE HRS...WINDS WILL DROP OFF TO A GENERAL 15-20KT RANGE. A SMALL CRAFT ADVISORY IS IN EFFECT FOR THE WATERS THURSDAY. WINDS WILL DIMINISH BY THURSDAY EVENING WITH HIGH PRESSURE OVERHEAD. HOWEVER...THE HIGH WILL MOVE OFF THE COAST THURSDAY NIGHT AND A COLD FRONT IS EXPECTED TO PASS THROUGH FRIDAY. ANOTHER COLD FRONT WILL LIKELY PASS THROUGH THE WATERS SATURDAY BEFORE STALLING OUT TO THE SOUTH FOR SUNDAY. A SMALL CRAFT ADVISORY MAY BE NEEDED FOR PORTIONS OF THE WATERS FRIDAY THROUGH SUNDAY.
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&& .FIRE WEATHER...
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A RED FLAG WARNING HAS REPLACED THE FIRE WEATHER WATCH FOR MUCH OF THE MID ATLC REGION TODAY. GUSTY WINDS WILL BE STRONGER OVER NRN AND ERN MD...THOUGH THE LOWEST RHS/HIGHEST TEMPS WILL BE OVER THE LOWER NRN VA PIEDMONT. ONLY LOCALIZED AREAS RECEIVED A COUPLE/FEW TENTHS OF AN INCH OF RAINFALL YESTERDAY...WHICH WILL FAIRLY QUICKLY BE NULLIFIED BY THE RELENTLESS AND DRY NW WINDS FOR MOST OF TODAY. GUSTY WINDS OF 20-30MPH HAVE ALREADY BEEN SPREADING ACROSS THE REGION IN THE PAST FEW HRS...GETTING STRONGER AND DRIER AFTER SUNRISE. TEMPS WILL RISE INTO THE 60S TODAY AND DEWPOINTS WILL DROP TO THE U20S/L30S. LATER THIS EVE...WINDS WILL BEGIN TO DROP DOWN TO MORE OF A 10-15MPH BREEZE. DRIER AIR WILL CAUSE EVEN LOWER RH VALUES THURSDAY...BUT WINDS WILL NOT BE AS STRONG. A FIRE WEATHER WATCH IS IN EFFECT FOR PORTIONS OF CENTRAL AND NORTHEASTERN MARYLAND WHERE THE WINDS WILL BE STRONGEST. A COLD FRONT WILL PASS THROUGH THE AREA FRIDAY...BRINGING A FEW SHOWERS BUT RAINFALL AMOUNTS WILL LIKELY AVERAGE OUT TO BE LIGHT.
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&& .TIDES/COASTAL FLOODING...
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STRONG NORTHWEST WINDS ARE EXPECTED TODAY AND THIS WILL CAUSE TIDAL BLOWOUT. THE NORTHWEST FLOW WILL CONTINUE THROUGH THURSDAY...BUT NOT AS STRONG. HOWEVER...TIDAL BLOWOUT CONDITIONS ARE POSSIBLE DURING THIS TIME AS WELL.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...RED FLAG WARNING FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR DCZ001. FIRE WEATHER WATCH FROM THURSDAY MORNING THROUGH THURSDAY AFTERNOON FOR DCZ001. MD...RED FLAG WARNING FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR MDZ003>007-009>011-013-014-016>018-502. FIRE WEATHER WATCH FROM THURSDAY MORNING THROUGH THURSDAY AFTERNOON FOR MDZ004>007-009>011-013-014-018. VA...RED FLAG WARNING FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR VAZ025>031-036>040-042-050>057-501-502-504. FIRE WEATHER WATCH FROM THURSDAY MORNING THROUGH THURSDAY AFTERNOON FOR VAZ054. WV...RED FLAG WARNING FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR WVZ050>053-055-502-504-506. MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT EARLY THIS MORNING FOR ANZ530>543. SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 PM EDT THURSDAY FOR ANZ530>543. GALE WARNING UNTIL 6 PM EDT THIS EVENING FOR ANZ530>543.
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&& $$ SYNOPSIS...BJL NEAR TERM...GMS SHORT TERM...BJL LONG TERM...BJL/GMS AVIATION...BJL/GMS MARINE...BJL/GMS FIRE WEATHER...BJL TIDES/COASTAL FLOODING...GMS/BJL

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