Area Forecast Discussion
Issued by NWS Sterling, VA

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KLWX 311431 AAA AFDLWX AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 1031 AM EDT TUE MAR 31 2015 .SYNOPSIS... HIGH PRESSURE WILL SLIDE OFF THE MIDDLE ATLANTIC COAST TODAY. LOW PRESSURE AND A TRAILING COLD FRONT WILL MOVE THROUGH THE REGION THIS 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. && .NEAR TERM /THROUGH TONIGHT/... MULTIFACETED WEATHER SYSTEM TO IMPACT THE MIDDLE ATLANTIC REGION THIS AFTERNOON INTO THIS EVENING. WATER VAPOR IMAGERY SHOWS A VIGOROUS UPPER SHORTWAVE/VORT MAX SLIDING ACROSS THE GREAT LAKES AND OHIO VALLEY WITH A FORMIDABLE SURFACE LOW. OUT AHEAD OF THIS FEATURE...ABUNDANT SUNSHINE AND MILD CONDITIONS ARE IN PLACE WITH TEMPERATURES ALREADY CLIMBING INTO THE 50S AND EVEN NEAR 60 IN A FEW LOCATIONS. HAVE BUMPED UP EXPECTED HIGH TEMPERATURES A COUPLE DEGREES EAST OF THE BLUE RIDGE. SURFACE LOW WILL SLIDE ACROSS THE NORTHERN PORTION OF THE FORECAST AREA THIS AFTERNOON...PUSHING A COLD FRONT THROUGH THE REGION. BUFKIT SOUNDINGS INDICATE AN INVERTED-V SUBCLOUD LAYER WITH SKINNY CAPE ABOVE. WINDS JUST OFF THE DECK ALSO APPROACH 40KTS. SOME OF THE SHOWERS THAT DEVELOP COULD CONTAIN GUSTY WINDS ABOVE 40 MPH ESPECIALLY FOR AREAS EAST OF THE BLUE RIDGE. MAIN THREAT WILL BE THIS LATER THIS AFTERNOON AND EVENING. IN ADDITION...GRADIENT WINDS WILL INCREASE BEHIND THE FRONT AND GUSTS COULD APPROACH WIND ADVISORY CRITERIA MAINLY OVER THE RIDGE TOPS. CURRENTLY THERE ARE NO HEADLINES UP FOR THIS POTENTIAL. WILL MONITOR CLOSELY. FURTHER SOUTH AND WEST...MUCH DRIER DOWNSLOPE FLOW WILL OCCUR LEADING TO THE THREAT FOR CRITICAL FIRE WEATHER CONDITIONS ESPECIALLY OVER PORTIONS OF THE CENTRAL VA PIEDMONT AND CENTRAL SHENANDOAH VALLEY. PLEASE REFER TO THE FIRE WEATHER DISCUSSION BELOW. 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. WINDS WILL GRADUALLY DIMINISH. && .SHORT TERM /WEDNESDAY/... 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. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... 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. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... 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. GUSTS TO 35 KTS COULD DEVELOP IN THE HEAVIER SHOWERS/STORMS. 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. && .MARINE... POTENT LOW PRESSURE WILL MOVE TOWARD THE REGION THIS AFTERNOON BEFORE PASSING THROUGH THE WATERS LATE AFTERNOON OR EARLY EVENING.. 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 TONIGHT AND NORTHWEST WINDS ARE EXPECTED BEHIND THE BOUNDARY. A SMALL CRAFT ADVISORY IS IN EFFECT FOR ALL OF THE WATERS THIS EVENING...AND FOR THE MIDDLE PORTION OF THE BAY AND LOWER TIDAL POTOMAC RIVER OVERNIGHT. 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.&& .FIRE WEATHER... 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. && .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 THIS AFTERNOON INTO THIS EVENING. GUSTY NORTHWEST WINDS WILL CAUSE ANOMALIES TO RAPIDLY FALL BEHIND A COLD FRONT LATER TONIGHT. && .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. WV...NONE. MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 AM EDT WEDNESDAY FOR ANZ532>534-537-540>543. GALE WARNING UNTIL 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. && $$ SYNOPSIS...KRW NEAR TERM...KRW SHORT TERM...KS LONG TERM...BAJ AVIATION...BAJ/KRW MARINE...BAJ/KRW FIRE WEATHER... TIDES/COASTAL FLOODING...

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.