Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 121734 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 134 PM EDT SAT APR 12 2014 .SYNOPSIS...
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HIGH PRESSURE BUILDS OFF THE MID ATLANTIC COAST TONIGHT INTO SUNDAY...AND REMAINS ANCHORED OFF THE COAST THROUGH MONDAY. A SLOW MOVING COLD FRONT APPROACHES FROM THE WEST MONDAY NIGHT AND TUESDAY.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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LATEST WX ANALYSIS SHOWING A RATHER DIFFUSE FRONTAL BOUNDARY EXTENDING NR/JUST SOUTH OF THE VA/NC BORDER EXTENDING SOUTH INTO NORTH CENTRAL NORTH CAROLINA...AS A ~1024MB SFC HIGH HAS BECOME CENTERED ALONG THE SOUTHEAST COAST. PLEASANT WX EXPECTED FOR THE BALANCE OF THE DAY. FRONTAL BOUNDARY WILL CONTINUE TO WASH OUT THROUGH MID- AFTERNOON, WITH LITTLE MORE THAN SOME SCT AFTERNOON CU PERSISTING ACROSS THE SOUTHEAST COAST THROUGH EARLY EVENING. LIGHT ONSHORE FLOW BEHIND THE FRONT WILL LIMIT HIGHS ALONG THE IMMEDIATE COASTLINES...WITH LOW/MID 60S EXPECTED ALONG THE ATLANTIC COAST OF THE EASTERN SHORE...AND UPPER 60S/LOW 70S EXPECTED FOR COASTAL SE VA/NE NC. FARTHER INLAND, LOOK FOR HIGHS INTO THE MID TO UPPER 70S FOR MOST OF CENTRAL VA, INTERIOR SECTIONS OF THE EASTERN SHORE AND NE NC. DEWPOINTS HAVE DROPPED INTO THE 30S TO LOW 40S BEHIND THE FRONT RESULTING IN MIN RH VALUES OF 25-30% ACROSS MUCH OF CENTRAL VA. HOWEVER...LIGHT WINDS WILL BE VERY LIGHT AVERAGING NE ~5-8 MPH.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/... SURFACE HIGH PRESSURE STRENGTHENS OFF THE MID ATLANTIC COAST TONIGHT INTO SUNDAY IN RESPONSE TO A BUILDING MID/UPPER RIDGE OVER THE WESTERN ATLANTIC. THIS WILL ONCE AGAIN ALLOW THE WIND TO SHIFT TO SOUTHERLY...WHICH WILL BOOST HIGHS SUNDAY INTO THE UPPER 70S/LOW 80S AWAY FROM THE COASTS UNDER A MOSTLY SUNNY SKY. HIGHS WILL BE LOCALLY COOLER ALONG THE COASTS...ESPECIALLY THE ATLANTIC COAST OF THE EASTERN SHORE WHERE MAXIMA MAY ONLY HOLD IN THE LOW/MID 60S. AN AREA OF LOW PRESSURE WILL TRACK FROM THE OHIO VALLEY INTO THE EASTERN GREAT LAKES SUNDAY NIGHT INTO MONDAY. ANY CHC OF RAIN SHOULD HOLD OFF UNTIL MONDAY NIGHT AS THERE IS PLENTY OF MID-LEVEL DRY AIR ASSOCIATED WITH THE WESTERN ATLANTIC RIDGE. HIGHS MONDAY SHOULD BE IN THE MID/UPPER 70S (LOCALLY COOLER ALONG THE COASTS) UNDER A PARTLY SUNNY SKY. && .LONG TERM /TUESDAY THROUGH FRIDAY/... THE MEDIUM RANGE PERIOD WILL BEGIN WITH ACTIVE WX AS A STRONG COLD FRONT WILL BE APPROACHING FROM THE WEST. AMPLIFIED/DEEP MID/UPPER LEVEL TROUGH WILL TAP INTO DEEP GULF OF MEXICO MOISTURE...SO WILL CONTINUE WITH HIGH END LIKELY POPS (70%) FOR ALL ZONES AT SOME POINT BY TUE (THE UNCERTAINTY IS MORE WITH RESPECT TO EXACT TIMING) AND SHOULD BE ABLE TO TREND TO EVEN HIGHER POPS OVER THE NEXT DAY OR TWO. HIGHS WILL TREND DOWN INTO THE 60S TO LWR 70S SE ON TUE DUE TO CLOUDS AND PRECIP. FAVORING THE LATEST ECMWF OVER THE GFS BUT NO OPERATIONAL MODEL HAS BEEN FOLLOWED EXCLUSIVELY FOR THE TAIL END PERIOD OF THE SYSTEM BY WED. THE ECMWF WOULD KEEP CONDITIONS WET WED INTO WED NIGHT AS A SECOND UPPER LEVEL SHORTWAVE PUSHES FROM THE SE TO MID ATLC STATES (THE GFS WOULD BRING DRY BUT COOL CONDITIONS). AT THIS POINT...HAVE BUMPED UP CLOUD COVER AND LINGERED CHC POPS INLAND TO LOW END LIKELY POPS ALONG THE COAST THROUGH MIDDAY WED. TEMPS WILL TREND RATHER CHILLY...WITH HIGHS ONLY IN THE 50S (CERTAINLY COULD BE ONLY IN THE 40S IF ECMWF SOLUTION WERE TO VERIFY). CLEARING/COOLER WED NIGHT WITH LOWS IN THE 30S TO LWR 40S. DRY/PARTLY CLOUDY THU-FRI WITH HIGHS IN THE 50S TO LOWER 60S AND LOWS IN THE 30S AND 40S AS SFC HIGH PRESSURE BUILDS FROM THE OHIO VALLEY TO NEW ENGLAND AND RIDGES DOWN INTO THE MID ATLC STATES. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... VFR CONDITIONS PREVAIL EARLY THIS MORNING AS A WEAK COLD FRONT SETTLES OVER THE REGION. THE FRONT WILL DISSIPATE TODAY AS HIGH PRESSURE CENTERS JUST OFF THE MID-ATLANTIC COAST. WINDS WILL BACK TO THE NORTH BEHIND THE FRONT...AND THEN TO THE NE AND E THIS AFTERNOON...REMAINING AOB 10 KT. MID-HIGH LEVEL CLOUDS GENERALLY AOA 12K FT AGL WILL PASS OVER THE TAF SITES EARLY THIS MORNING BEFORE BECOMING CLEAR LATER THIS MORNING. OTHERWISE...FEW-SCT CLOUDS WITH DECKS 4-6K FT AGL POSSIBLE THIS AFTERNOON. HIGH PRESSURE PUSHES FARTHER OFFSHORE TONIGHT AS WINDS BECOME SLY. STALLED FRONTAL BOUNDARY WILL LIFT NWD OVERNIGHT AS A WARM FRONT...WITH SOME FOG POSSIBLE OVER THE ERN SHORE AND TAF SITE KSBY. VFR CONDITIONS EXPECTED AGAIN ON SUNDAY BEFORE A COLD FRONT APPROACHES THE REGION ON MONDAY. THE FRONT WILL BRING WIDESPREAD PRECIP TO THE REGION MON NIGHT INTO WEDS. && .MARINE... WEAK COLD FRONT WILL CONTINUE TO SETTLE OVER THE WATERS EARLY THIS MORNING. IN ADVANCE OF THE FRONT...SW WINDS ARE GENERALLY 10-15 KT WITH A FEW GUSTS NEAR 20 KT THANKS TO A MODEST PRESSURE GRADIENT. SCA CONDITIONS ARE NOT ANTICIPATED. BEHIND THE FRONT...WINDS HAVE BACKED TO THE NW AND DIMINISHED AOB 10 KT. WAVES REMAIN 1-2 FT AND SEAS 2 TO 4 FT. THE FRONT WILL SETTLE NEAR THE VA/NC BORDER EARLY-MID MORNING...WITH WINDS OVER THE WATER BACKING TO THE N AND THEN NE. HIGH PRESSURE WILL SLIDE JUST OFF THE MID-ATLANTIC COAST...WITH WINDS THEN BECOMING WLY AOB 10 KT THIS AFTERNOON. HIGH PRESSURE WILL STRENGTHEN OFF THE MID-ATLANTIC COAST TONIGHT AND SUNDAY WITH PERSISTENT SLY WINDS. GRADIENT OVER THE MID-ATLANTIC WILL STRENGTHEN BTWN HIGH PRESSURE OFFSHORE AND LOW PRESSURE OVER THE MIDWEST INTO THE GREAT LAKES. INVERSION WILL LIKELY PREVENT STRONGER WINDS ALOFT FROM MIXING DOWN. HOWEVER...STRONGER MIXING OVER LAND COULD PUSH SOME 20 KT GUSTS OUT OVER THE ADJACENT WATERS. HAVE UNDERCUT GFS GUIDANCE...WHICH MEANS WAVEWATCH IS TOO HIGH WITH SEAS. SLY WINDS ARE SLOW TO BUILD SEAS OVER THE NRN WATERS...SO HAVE CAPPED SEAS AT 4 FT SUN NIGHT INTO MON. A STRONG COLD FRONT WILL APPROACH FROM THE WEST ON MONDAY...CROSSING THE WATERS MON NIGHT-TUES. SLY WINDS WILL INCREASE IN ADVANCE OF THE FRONT MON-MON NIGHT WITH SCA CONDITIONS POSSIBLE. SEAS WILL ALSO BUILD MON-MON NIGHT. MODELS DIVERGE AS TO WHAT HAPPENS BEHIND THE FRONT TUE NIGHT INTO WED...BUT EITHER WAY EXPECT A STRONG SURGE OF COLD AIR AND STRONG SCAS OR POSSIBLY GALES TUE NIGHT INTO WED IN N/NE FLOW. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...AJZ NEAR TERM...AJZ/MAM SHORT TERM...AJZ/DAP LONG TERM...LKB AVIATION...SAM MARINE...SAM

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