Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 312041 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 441 PM EDT TUE MAR 31 2015 .SYNOPSIS... LOW PRESSURE AND A TRAILING COLD FRONT WILL MOVE THROUGH THE REGION THIS EVENING. HIGH PRESSURE WILL THEN BUILD INTO THE MIDDLE ATLANTIC THROUGH WEDNESDAY AND THURSDAY. ANOTHER COLD FRONT IS EXPECTED TO CROSS THE AREA FRIDAY INTO SATURDAY. HIGH PRESSURE WILL RETURN FOR SUNDAY. && .NEAR TERM /THROUGH WEDNESDAY/... ...UPDATE TO EXTEND WIND ADVISORY FOR RIDGE TOPS OF BLUE RIDGE MOUNTAINS AND POTOMAC HIGHLANDS UNTIL MIDNIGHT. THE GALE WARNING ALSO GOES UNTIL MIDNIGHT FOR THE WATERS... LOW PRESSURE AND ASSOCIATED COLD FRONT WILL SWEEP ACROSS THE MIDDLE ATLANTIC REGION THIS EVENING. TEMPERATURES OUT AHEAD OF THE FRONT HAVE WARMED INTO THE 60S WITH A FEW 70 DEGREE READINGS OVER CENTRAL VA. WINDS WILL REMAIN GUSTY ACROSS MUCH OF THE FORECAST AREA THE REMAINDER OF THIS AFTERNOON INTO THIS EVENING. SUSTAINED WINDS OF 15 TO 25 MPH WITH GUSTS TO 35 MPH WILL BE COMMON...EXCEPT UP TO 50 MPH ABOVE 1500 FEET WITHIN THE BLUE RIDGE AND POTOMAC HIGHLANDS. SHOWERS AND ISOLATED THUNDERSTORMS WILL ALSO DEVELOP...ESPECIALLY OVER THE BALTIMORE AND WASHINGTON DC METRO AREAS AND SURROUNDING SUBURBS TO THE NORTH AND WEST. BUFKIT PROFILES INDICATED AN INVERTED-V SUBCLOUD LAYER AND THIN CAPE...INDICATIVE OF GUSTY WIND POTENTIAL. ANY THUNDERSTORM THAT DOES DEVELOP WILL HAVE THE POTENTIAL TO BRING DOWN STRONGER WIND GUSTS AOA 40 MPH. THE SHOWER ACTIVITY WILL LIKELY CLEAR THE BAY COMMUNITIES AROUND 03Z. FURTHER SOUTH OVER THE SHENANDOAH VALLEY AND PORTIONS OF THE VIRGINIA PIEDMONT...CRITICAL FIRE WEATHER CONDITIONS ARE LIKELY TO OCCUR WITH A COMBINATION OF STRONG WINDS AND LOW HUMIDITIES. PLEASE REFER TO THE FIRE WEATHER DISCUSSION BELOW FOR FURTHER DETAILS. MUCH COOLER TEMPERATURES WILL FOLLOW BEHIND THE COLD FRONT OVERNIGHT AND WINDS WILL GRADUALLY DIMINISH. LOW TEMPERATURES WILL BOTTOM OUT IN THE 30S IN MOST LOCATIONS...EVEN A FEW 20S OUT WEST AND NEAR THE MASON DIXON LINE. HIGH PRESURE WILL BUILD BACK INTO THE REGION ON WEDNESDAY BRINGING A RETURN TO SUNSHINE BUT WITH COOLER HIGH TEMPERATURES IN THE 50S TO NEAR 60 IN SPOTS. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... HIGH PRESSURE WILL MAKE ABOUT A TWO-DAY VISIT DURING THE MIDDLE OF THE WEEK...ATTEMPTING TO HANG ON THRU THE END OF THE WORK WEEK AS ANOTHER COMPLEX LOW PRESSURE SYSTEM APPROACHES. THE EFFECT ON THU FROM THIS HIGH WILL BE ANOTHER WELL-ABOVE AVERAGE DAY IN TERMS OF TEMPS. S-SW WINDS CHANNELING THRU THE VLYS OF THE APLCNS WILL BRING TEMPS WELL INTO THE 70S AND POSSIBLY SOME L80S...WHILE THE PIEDMONT/COASTAL REGION STAYS A BIT MORE MODERATED BUT STILL NEAR THE 70F DEG MARK BY MID AFTN. MEANWHILE...A LARGE BUT FAIRLY DISORGANIZED FETCH OF GULF MOISTURE WILL BE COLLECTING OVER THE MS RVR VLY AND DEEP SOUTH...AS A SERIES OF UPPER WAVES BEGIN TO SHAPE IT WELL TO OUR WEST. A LONG OUTSTRETCHED WARM FRONTAL REGION WILL BE SET UP TO OUR NORTH...FROM THE UPPER MIDWEST TO NEW ENGLAND AS WE HEAD INTO FRI. PLENTY OF PRECIP WILL BE HANGING AROUND THIS BOUNDARY...STAYING LARGELY NORTH AND WEST OF THE AREA UNTIL DAWN FRI. A WEAKER LOW PRES SYSTEM THAT WILL DEVELOP THU NIGHT INTO FRI WILL SLIDE UP TOWARD NEW ENGLAND...BUT A MORE POTENT LOW WILL BE FORMING OVER THE LOWER OHIO RVR VLY. THE LOW WILL STAY TO OUR NORTH AS IT APPROACHES...BUT THE COLD FRONT WILL BE STRENGTHENING THRU THE DAYTIME HRS. POCKETS OF PRE-FRONTAL SHOWERS WILL SPREAD OVER THE AREA DURING THE FIRST HALF OF THE DAY...AS TEMPS RISE BACK INTO THE 60S/70S. THE COLD FRONT WILL THEN MOVE THRU THE REGION LATE INTO THE NIGHTTIME HRS. CONVECTIVE POTENTIAL WILL DEPEND ON WHATEVER LEFTOVER INSTABILITY THERE IS FROM THE AFTN/EVE HEATING AND MAY COME IN TOO LATE TO MAXIMIZE THIS POTENTIAL. HOWEVER...THE LOW-MID SHEAR WILL BE POTENT ENOUGH TO DRIVE AN ORGANIZED LINE - ALBEIT SHALLOW - BUT ENOUGH TO MIX DOWN GUSTY WINDS IN ISOLATED AREAS. && .LONG TERM /SATURDAY THROUGH TUESDAY/... COLD FRONT MOVES ACROSS THE CWA FRI NIGHT INTO SAT MORNING WHILE LOW PRESSURE MOVES NE FROM NORTHERN TX/OK. MOISTURE ASSOCIATED WITH THESE SYSTEMS MAY BRING AN EXTENDED PERIOD OF RAIN TO THE CWA ENDING LATE SAT MORNING INTO THE AFTERNOON. SOME UPSLOPE PRECIP TO THE WEST MAY LAST LONGER. ANOTHER COLD FRONT APPROACHES ON SAT NIGHT INTO SUN MORNING...GUIDANCE SUGGESTS THAT THE FRONT WILL BECOME STATIONARY OVER THE MID-ATLANTIC REGION INTO MON NIGHT. WINDY CONDITIONS FROM FRI INTO SAT NIGHT ARE ANTICIPATED. BELOW NORMAL TEMPS ARE EXPECTED FOR SAT NIGHT BEHIND THE COLD FRONT. && .AVIATION /21Z TUESDAY THROUGH SUNDAY/... GUSTY WINDS WILL PERSIST AT ALL TERMINAL SITES INTO THIS EVENING. WIND SPEEDS OF 15 TO 25 KTS WITH GUSTS TO 30 KTS WILL BE COMMON AT THE TERMINALS. SHOWERS...PERHAPS AN ISOLATED THUNDERSTORM WILL BE POSSIBLE ESPECIALLY FROM KDCA TO KMTN TO KBWI TO KMRB. ANY THUNDERSTORMS THAT DO DEVELOP WILL BE CAPABLE OF PRODUCING STRONGER WIND GUSTS OF 35 TO 40 KTS. COLD FRONT WILL PUSH THROUGH LATER THIS EVENING AND VFR CONDITIONS ARE EXPECTED ALONG WITH DIMINISHING WINDS. VFR WILL PERSIST ON WEDNESDAY. SOLID VFR CONDS ON THU AS A LOW PRES SYSTEM APPROACHES INTO EARLY FRI. THIS SYSTEM WILL TAKE A COUPLE OF DAYS TO PASS COMPLETELY...W/ SOME ISOLATED CONVECTIVE ACTIVITY W/ A COLD FRONT LATE FRI NIGHT AND RAIN SHOWERS ON EITHER SIDE OF THE LINE. COLD FRONT MOVES ACROSS REGION FRI NIGHT... BRINGING RAINY CONDITIONS THROUGH SAT. WINDY CONDITIONS ARE EXPECTED FROM FRI NIGHT INTO SAT NIGHT. VFR CONDITIONS FOR LATE SAT NIGHT INTO SUN. && .MARINE... GUSTY WINDS OCCURRING OVER THE WATERS. GALE CONDITIONS ARE STILL POSSIBLE AS A COLD FRONT MOVES EAST ACROSS THE REGION. SHOWERS AND ISOLATED THUNDERSTORMS THAT DEVELOP WILL BE CAPABLE OF MIXING DOWN 30 TO 40 KT WIND GUSTS. ALL OF THE ACTIVITY SHOULD CLEAR THE WATERS BY 04Z. GALE WARNING CONTINUES UNTIL MIDNIGHT...AND SCA WINDS WILL PERSIST INTO EARLY WEDNESDAY MORNING BEFORE DIMINISHING UNDER HIGH PRESSURE DURING THE DAY. HIGH PRES MOVING OFFSHORE WED NIGHT INTO THU WILL CREATE PRES GRADIENT STRONG ENOUGH FOR SCA CONDS OVER THE WATERS BOTH THU AND FRI AFTNS. A STRONG COLD FRONT WILL SLIDE THRU THE REGION LATE FRI NIGHT. SCA LIKELY FRI NIGHT INTO SAT BEHIND COLD AS WINDY CONDITIONS DEVELOP. SUB-SCA CONDITIONS LATE SAT NIGHT. && .FIRE WEATHER... RED FLAG CONDITIONS EXPECTED THE REMAINDER OF THIS AFTERNOON INTO THE EARLY EVENING FOR SEVERAL VIRGINIA COUNTIES IN THE HIGHLANDS...SHENANDOAH VALLEY...BLUE RIDGE AND CENTRAL FOOTHILLS. SUSTAINED WINDS OF 20 MPH WITH HIGHER GUSTS ALONG WITH RH VALUES BELOW 30 PERCENT ARE EXPECTED. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...NONE. MD...NONE. VA...RED FLAG WARNING UNTIL 6 PM EDT THIS EVENING FOR VAZ025>027- 029-030-036>040-050-051-501-502-504-507-508. WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR VAZ025>027-029- 503-504-507-508. WV...WIND ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR WVZ055-501-502- 505-506. MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 6 AM EDT WEDNESDAY FOR ANZ532>534-537-540>543. GALE WARNING UNTIL MIDNIGHT EDT TONIGHT FOR ANZ530>543. SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 2 AM EDT WEDNESDAY FOR ANZ530-531-535-536-538-539. && $$ SYNOPSIS...KRW NEAR TERM...BJL/KRW SHORT TERM...GMS LONG TERM...IR AVIATION...GMS/IR/KRW MARINE...BJL/GMS/IR/KRW FIRE WEATHER...KRW

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