Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 051935 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 335 PM EDT TUE MAY 5 2015 .SYNOPSIS...
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HIGH PRESSURE WILL REMAIN WELL OFF THE SOUTHEAST AND MID ATLANTIC COAST THROUGH TONIGHT...BRINGING VERY WARM AND MAINLY DRY CONDITIONS TO THE LOCAL AREA. A BACKDOOR COLD FRONT APPROACHES FROM THE NORTH TONIGHT...THEN DROPS INTO VIRGINIA LATE WEDNESDAY INTO EARLY THURSDAY...BEFORE DISSIPATING. LOW PRESSURE WILL SPIN OFF OR NEAR THE SOUTHEAST COAST THURSDAY INTO SATURDAY.
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&& .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
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LATEST ANALYSIS REVEALS SFC HIGH PRESSURE CENTERED WELL OFFSHORE OF THE VA/NC COAST, EXTENDING BACK ACROSS EASTERN NC. ~1006 MB LOW PRESSURE WAS ANALYZED ACROSS NEWFOUNDLAND, WITH SFC COLD FRONT SNAKING BACK ACROSS NEW ENGLAND INTO NE PA/NW NJ AND THE EASTERN GRT LAKES. A PRE-FRONTAL SFC TROUGH EXTENDS SW FROM SE PA INTO SRN MD AND NORTHERN VA. HAVE NOTED SOME INCREASING CU OVER THE PAST FEW HOURS ALONG THE BLUE RIDGE AND EXPECT TO SEE A BIT MORE TO DEVELOP ACROSS WESTERN SECTIONS OF THE LOCAL AREA ALONG THE TROUGH BY OVER THE NEXT FEW HOURS. DO HAVE SOME LOW CHANCES FOR SHOWERS/TSTMS ACRS THE FAR N/NW LATE THIS AFTN/EVENING. EXPECT ANY SHOWERS TO BE SHORT LIVED OWING TO FLAT/QUASI-ZONAL FLOW ALOFT AND SHOULD THEREFORE ALLOW LIMITED CONVECTIVE DEVELOPMENT AND WILL YIELD A VERY SLOW SOUTHWARD PROGRESSION OF THE FRONT THROUGH TONIGHT AND INTO TOMORROW. BY TONIGHT, SHORTWAVE ENERGY NOTED ON IR SAT ACRS THE LWR GRT LAKES WILL DAMPEN AS IT DIVES SOUTHEAST ACROSS THE NORTHERN MID- ATLANTIC. RESULTANT UPPER FLOW SHIFTS TO THE WNW, AND WOULD ALLOW ANY LIGNERING SHOWERS AND STORMS TO CROSS A BIT FARTHER TO THE SOUTH. GIVEN THE LIMITED ACTIVITY THUS FAR, AND W/ HRRR NOT OVERLY EXCITED ABOUT ACTIVITY TONIGHT, WILL HANG ON TO A 30-40% RAIN CHANCE FOR SOME SCT SHRAS THIS EVENING ACROSS THE WEST, AND LATE TONIGHT/OVERNIGHT FOR THE EASTERN SHORE. FARTHER S-SE, EXPECT DRY CONDS TO CONTINUE UNDER A PARTLY CLOUDY SKY. LOWS TONIGHT IN THE UPPER 50S TO LWR 60S.
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&& .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
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HAVE LINGERED A SLIGHT CHC FOR LINGERING SHOWERS JUST AFTER SUNSET TOMORROW MORNING...W/AREA OF WEAK LIFT SLIDING ESE ALONG AND AHEAD OF THE BACKDOOR FRONT COINCIDENT WITH PLENTY OF LINGERING LLVL MOISTURE. ANY SHOWERS WOULD BE BRIEF AND WIDELY SCT AT MOST. OTHERWISE...DRY IN THE MORNING FOR MOST. EARLY SUN WILL GIVE WAY TO INCREASING AFTN CLOUDS ACROSS CENTRAL/SOUTHERN ZONES. STRONG HEATING AND THE ARRIVAL OF THE FRONT WILL LIKELY PROVIDE THE TRIGGER FOR SOME SCT AFTN SHRAS/THUNDERSTORMS...MAINLY OVR WRN AND NRN COUNTIES LATE IN THE AFTN INTO WED NIGHT. FOR TEMPS, STILL ON THE WARM SIDE OF THE GUIDANCE ENVELOPE IN EXPECTATION OF A SLOWER FRONTAL PROGRESSION...RESULTING IN A PARTLY TO MOSTLY SUNNY SKY EARLY AND HIGHS FM 80-85 WEST OF THE BAY...TO THE 70S ON THE ERN SHORE. FRONT BECOMES VERY DIFFUSE TOMORROW NIGHT AND WASHES OUT BY THE TIME IT REACHES THE VA/NC BORDER. MEANWHILE, SFC LOW PRES WILL BEGIN TO TAKE SHAPE AND CLOSE OFF ALONG THE EAST COAST OF FLORIDA/SE GA WED AFTN/NIGHT. WEAK SFC RIDGING WILL RE-ESTABLISH ITSELF OVERHEAD AND ALLOW FOR A DRY OVERNIGHT WED NIGHT INTO THU MORNING. HOWEVER, EXPECT A GOOD AMOUNT OF LOW TO MID LEVEL CLOUD TO LINGER OVERNIGHT INTO THU MORNING ALONG AND BEHIND THE FRONT ACROSS NORTHERN HALF OF THE AREA. GENERALLY PARTLY SUNNY FARTHER SOUTH A 20-30% CHC FOR A SHOWER OR TSTM, AGAIN MAINLY IN THE AFTN/EARLY EVENING. E-NE WINDS WILL RESULT IN HI TEMPS RANGING THRU THE 70S TO NEAR 80 SW TO THE UPPER 60S/LWR 70S ERN SHORE. STILL MONITORING THE PROGRESS OF AFOREMENTIONED LOW ALONG THE SE COAST. MODELS STILL HAVING TROUBLE RESOLVING THIS SYSTEM...WHICH IS CASTING A BIT OF LOWER CONFIDENCE ON THE HANDLING OF THIS SYSTEM. THE 12Z/5 GFS CONTINUES TO BRING THE SFC LOW INLAND OF THE SC/NC COAST...WITH THE 12Z/NAM NOW IN CLOSE ENOUGH TO COVER THU NIGHT AND FRIDAY. ITS SOLUTION IS SLIGHTLY FASTER THAN THE GFS AND TAKES THE SURFACE LOW INLAND ACROSS EXTREME NE GA/COASTAL SC BY EARLY FRIDAY MORNING. FOR ITS PART, THE OPERATIONAL ECMWF REMAINS OFFSHORE, BUT HAS TRENDED TOWARD THE GFS IN MOVING A BIT CLOSER TO THE COAST WITH THE SFC LOW...AND EVEN KEEPS THE LOW NEARLY STATIONARY ALONG THE CAROLINA COAST FOR FRIDAY AND THROUGH THE WEEKEND. HAVE GONE WITH A GFS WEIGHTED GFS/ECMWF BLEND FOR FRIDAY UNTIL MODELS COME INTO A BIT CLOSER AGREEMENT. EITEHR WAY, EXPECT FRIDAY TO BE PREDOMINATELY DRY ACROSS THE LOCAL AREA, BUT SHOULD SEE SOME (MAINLY) DIURNALLY DRIVEN SCT SHOWERS/TSTMS POSSIBLE OVER THE SOUTHERN HALF OF THE AREA (BEST CHC SOUTH OF THE BORDER INTO NC). HIGHS 80-85 INLAND, COOLER U60S TO M70S ALONG THE COAST IN CONTINUED ONSHORE FLOW.
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&& .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... MEDIUM RANGE PERIOD HIGHLY DEPENDENT PERSISTENT UPPER RIDGE OVER THE EAST, AS WELL AS THE DEVELOPMENT AND EVENTUAL PROGRESS OF EXPECTED DEVELOPMENT OF AN AREA OF LOW PRESSURE OFF THE EAST COAST OF FLORIDA. MODELS ARE IN GENERAL AGREEMENT OF THE DEVELOPMENT AND INITIAL SLOW DRIFT NORTHWARD ON WEDNESDAY. THE HURRICANE CENTER IS CONTINUING TO MONITOR THIS FEATURE FOR POTENTIAL SUBTROPICAL DEVELOPMENT. SFC RIDGING TO THE NORTH AND W-NW FLOW ALOFT SHOULD FORCE THE LOW TO MEANDER AROUND A POSITION ALONG/JUST OFF THE SOUTHEAST COAST THROUGH THE WEEKEND. THE GEFS AND EURO ENSEMBLES BOTH CONTINUE TO TAKE THE LOW INLAND ALONG THE SC/GA COAST, AS DOES THE NEW 12Z/04 GFS. THE OPERATIONAL EUROPEAN, MEANWHILE CONTINUES TO KEEP THE SYSTEM OFFSHORE. A SOLUTION TOWARDS THE GFS REMAINS THE HPC PREFERENCE, AND HV EDGED THE FORECAST IN THIS DIRECTION. THIS SCENARIO WOULD YIELD SLIGHT CHC TO LOW CHC POP FOR MAINLY DIURNALLY DRIVEN SHOWERS/T-STORMS AT MOST ACROSS OUR AREA. LOWEST CHANCES WILL BE ACROSS THE NORTH WITH SFC RIDGING IN PLACE NORTH OF THE AREA. OTHER HEADLINE FOR THE PERIOD WILL BE THE WARMER TEMPERATURES. E-SE FLOW WILL BRING A MODEST INCREASE IN HUMIDITY, AND INCREASING LOW LEVEL THICKNESSES FAVOR WARM HIGHS IN THE 80S UNDER A PARTLY TO MOSTLY SUNNY SKY. EARLY MORNING LOWS LOOK TO REMAIN WELL INTO THE 50S TO MID 60S LATE WEEK INTO EARLY NEXT WEEK. && .AVIATION /20Z TUESDAY THROUGH SUNDAY/... HIGH PRESSURE GENERALLY IN CONTROL OVER THE MID-ATLANTIC THIS AFTERNOON WITH A WEAK SURFACE TROUGH TO THE NORTH OF THE AKQ CWA. A COLD FRONT REMAINS OVER SOUTHERN NY STRETCHING WEST INTO PA AND OH. SWLY WINDS 10-15 KT CONTINUE WITH A FEW AFTERNOON GUSTS AROUND 20 KT. SHOWERS/THUNDERSTORMS DEVELOP ALONG THE FRONT LATE TODAY...DROPPING SWD TOWARD THE NRN LOCAL AREA TONIGHT. WILL LIKELY SEE AN INCREASE IN MID-HIGH CLOUDS EARLY TONIGHT AT KSBY AND KRIC...WITH SHOWERS (POSSIBLY A THUNDERSTORM) POSSIBLE LATE TONIGHT AT KSBY. OUTLOOK: THERE WILL BE A DAILY CHANCE FOR MAINLY AFTN AND EARLY EVENING SHOWERS AND THUNDERSTORMS WEDNESDAY THROUGH SATURDAY. THEY ARE NOT EXPECTED TO BE WIDESPREAD. OTHERWISE MAINLY VFR CONDITIONS ARE EXPECTED DURING THE PERIOD. LATE IN THE WEEK...PATCHY FOG WILL BE PSBL AROUND SUNRISE. && .MARINE... LATEST WEATHER ANALYSIS ACROSS THE WATERS DEPICTS HIGH PRESSURE CENTERED ROUGHLY 500 NM OFF THE MID ATLANTIC COAST AND LOW PRESSURE OVER NEWFOUNDLAND. AN ATTENDANT COLD FRONT EXTENDS FROM THE SFC LOW SWWD INTO NEW ENGLAND AND THE OH VALLEY. GRADIENT HAS RESULTED IN A PERIOD OF MARGINAL SCA CONDITIONS OVER THE BAY AND LOWER JAMES RIVER EARLY THIS MORNING...WITH OCCASIONAL GUSTS 20-25 KT. HAVE OPTED TO ISSUE SCA HEADLINES THRU 7 AM AS GRADIENT EXPECTED TO RELAX AND LOW LEVELS STABILIZE. WAVES GENERALLY 2-3 FT AND SEAS AROUND 3 FT. HIGH PRESSURE PUSHES FARTHER OFFSHORE TODAY AS THE COLD FRONT SLOWLY APPROACHES FROM THE NORTH. S-SW WINDS GENERALLY 10-15 KT TODAY...WITH OCCASIONAL GUSTS TO 20 KT IN THE COASTAL WATERS. SLIGHT UPTICK IN WINDS POSSIBLE AGAIN TONIGHT...BUT NOT AS STRONG AS EARLY THIS MORNING AS THE WINDS ALOFT ARE PROGGED TO BE WEAKER. THE COLD FRONT IS PROGGED TO REACH THE NRN WATERS LATE WEDS...DROPPING ACROSS THE WATERS WEDS NIGHT INTO THURS. THE FRONT THEN WASHES OUT OVER THE REGION THURS AS LOW PRESSURE LOCATES OFF THE SE COAST. FLOW BEHIND THE FRONT BECOMES NELY...REMAINING AOB 15 KT. SEAS ONLY PROGGED TO BUILD TO 3-4 FT WEDS NIGHT-THURS. UNCERTAINTY STILL EXISTS IN THE EXACT TRACK AND STRENGTH OF THE COASTAL LOW LATE IN THE WEEK. ATTM...MODELS KEEP THE LOW OFF THE SE COAST INTO THE WEEKEND. THIS TRACK STAYS TOO FAR SOUTH TO BRING ANY SIGNIFICANT INCREASE IN SEAS AND WINDS TO THE LOCAL AREA. OTHERWISE...HIGH PRESSURE REMAINS OVER THE LOCAL WATERS THRU THE WEEKEND WITH SE WINDS GENERALLY AOB 15 KT. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...MAM NEAR TERM...MAM SHORT TERM...LKB/MAM LONG TERM...MAM AVIATION...SAM/DAP MARINE...MAM/SAM

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