Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 310024 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 824 PM EDT THU OCT 30 2014 .SYNOPSIS...
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WEAK HIGH PRESSURE BUILDS ACROSS THE AREA THROUGH FRIDAY. A STRONG LOW PRESSURE SYSTEM WILL DEVELOP OFF THE MID ATLANTIC COAST SATURDAY AND SATURDAY NIGHT BEFORE EXITING THE AREA ON SUNDAY. HIGH PRESSURE RETURNS FOR THE BEGINNING OF NEXT WEEK.
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&& .NEAR TERM /THROUGH FRIDAY/... MIDDAY SFC ANALYSIS INDICATED SFC COLD FRONT WELL OFFSHORE, EXTENDING INTO THE DEEP SOUTH. MEANWHILE, ~1022 MB SFC HIGH PRESSURE CONTINUES TO BUILD INTO THE RGN FM THE WNW. ALOFT, 2 MAIN PLAYERS ARE A SHORTWAVE CUTTING ACROSS THE MID MISSOURI VALLEY INTO THE OZARKS WITH A SECOND, STRONGER SHORTWAVE DROPPING SOUTH ACROSS THE CANADIAN PRAIRIES THIS AFTN. FRONT WILL REMAIN IN PLACE OFFSHORE TONIGHT AS SFC HIGH BUILDS OVER THE REGION TONIGHT. FORECAST LOW TEMPS EARLY FRI MORNING INTO THE M/U30S INLAND TO ~ 50F ALONG SE COASTAL AREAS...UNDER A CLEAR TO MOSTLY CLEAR SKY. FRIDAY BEGINS MOSTLY CLEAR, WITH GRADUALLY INCREASING CLOUDS LATE AFTN/FRIDAY NIGHT. FRIDAY WILL BE THE TRANSITION DAY AS WEAKER SHORTWAVE CURRENTLY OVER THE OZARKS CARVES OUT AN EAST COAST TROUGH INTO THE DEEP SOUTH FRIDAY. MEANWHILE, STRONGER NORTHERN PLAINS TROUGH DROPS SOUTH FROM THE UPPER MIDWEST INTO THE OHIO VALLEY THROUGH FRIDAY AFTN. THE ASSOCIATED SFC LOW AND STRONG SFC COLD FRONT WILL PUSH ACROSS THE OHIO VALLEY TOWARDS THE CENTRAL APPALACHIANS FRIDAY AFTN AND EVENING. ACROSS THE LOCAL AREA, HV MAINTAINED A DRY FORECAST FRIDAY. MODEL CROSS SECTIONS STILL SHOWING A GOOD DEAL OF MID-LEVEL DRY AIR THAT WL NEED TO BE OVERCOME...SO WILL HOLD OFF ON POP UNTIL AFTER DARK FRIDAY NIGHT ACROSS THE PIEDMONT. OTHERWISE, NOTHING MORE THAN INCREASING MID TO HIGH CLOUDS TOMORROW AFTN/EVENING WITH HIGHS IN THE U50S NORTH TO LOW 60S SOUTHEAST INCLUDING ALONG THE COAST. DRY CONDITIONS FOR MOST TRICK OR TREATERS TOMORROW, WITH THE EXCEPTION OF A FEW SPRINKLES POTENTIALLY ALONG THE IMMEDIATE COAST ALONG THE COASTAL FRONT AND OVER THE PIEDMONT AHEAD OF NEXT SYSTEM. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/... SYNOPTIC REVIEW: STRONG UPPER SHORTWAVE WILL DIG CONTINUE TO DIG SOUTH FROM THE TN VALLEY ACROSS THE DEEP SOUTH ON SATURDAY. GOOD MODEL AGREEMENT DEPICTING UPPER LOW CLOSING OFF OVER THE CAROLINAS MIDDAY SAT. MODELS CONTINUE TO SPIN-UP SECONDARY CYCLOGENESIS OFFSHORE OF THE NC COAST SAT AFTN/EVENING, BEFORE QUICKLY EJECTING NORTHEAST AWAY FROM THE AREA LATE SAT NGT INTO SUNDAY MORNING. COOL 1030+MB HIGH PRESSURE WILL SETTLE EAST FROM THE MISSISSIPPI VALLEY LATE SATURDAY THROUGH MONDAY. FORECAST DETAILS/CONCERNS: 12Z/THU SUITE OF MODELS ARE IN GOOD AGREEMENT THAT RAIN WILL INCREASE IN COVERAGE LATE FRIDAY NIGHT THROUGH SATURDAY. BREEZY OVERALL ON SATURDAY, WITH BEST SURGE OF CAA LIKELY HOLDING OFF UNTIL SAT NGT. GIVEN FCST OF HOW FAR S UPR LVL SYSTEM TRACKS, MOST SIGNIFICANT IMPACTS APPEAR TO BE OVER FOR ERN/SERN CSTL LOCATIONS (PRIMARILY) FM MIDDAY SAT INTO EARLY SAT EVENING. ADDITIONALLY, A PERIOD OF STRONG NNE WNDS (35-45 MPH) EXPECTED ALONG COASTAL ZONES W/AREAS OF MINOR TIDAL FLOODING ALONG THE ATLC BEACHES (SEE COASTAL FLOODING SECTION BELOW). WILL HIGHLIGHT POTENTIAL IMPACTS IN HWO. A WIND ADVISORY MAY BE NEEDED OVER AT LEAST SOME OF OUR COASTAL ZONES SATURDAY NIGHT FOR A 6-10 HOUR PERIOD IF CURRENT FORECAST RATIONALE PANS OUT. PCPN WILL QUICKLY TAPER OFF SATURDAY NIGHT WITH SUBSIDENCE IN THE WAKE OF THE DEPARTING WAVE...AND SKY CLEARS OUT QUICKLY INTO SUNDAY MORNING AS SURFACE HIGH OF CANADIAN ORIGIN SINKS FROM THE OHIO VALLEY INTO THE SOUTHEAST SUNDAY INTO SUNDAY NIGHT. THIS WILL USHER IN THE COOLEST AIR OF THE SEASON TO DATE AND A WIDESPREAD FROST/FREEZE IS EXPECTED TO FOR MOST LOCATIONS JUST INLAND MONDAY MORNING.. FOR TEMPERATURES, WIDESPREAD CLOUDS, INCREASING RAIN CHCS WILL KEEP HIGHS IN THE 50S FOR MOST ON SATURDAY, WITH TEMPS POTENTIALLY NOT MAKING IT OUT OF THE 40S WELL INLAND. WELL MIXED ATM/BREEZY CONDITIONS WILL KEEP TEMPS FROM BOTTOMING OUT SATURDAY NIGHT, BUT STILL CHILLY WITH LOWS IN THE MID 30S INLAND TO LOW 40S ALONG THE COAST. DESPITE A MOSTLY SUNNY SKY, ONGOING CAA WILL KEEP HIGHS SUNDAY IN THE 50S...OR ROUGHLY -1 TO -1.5 STD DEV FROM CLIMO. THE SFC HIGH LOCATES ALONG THE SE COAST ON MONDAY, WITH RESULTANT LOW LEVEL SW FLOW ALLOWING FOR A MODEST WARMUP MONDAY...INTO THE U50S TO NEAR 60. && .LONG TERM /MONDAY THROUGH THURSDAY/... STRONG HIGH PRESSURE SETTLES OVER THE MID ATLANTIC SUNDAY NIGHT. BY MONDAY MORNING LOWS SHOULD FALL TO AROUND 30-32 FOR MUCH OF THE AREA (UPPER 20S POSSIBLE IN FAVORED COLD SPOTS)...WITH SLIGHTLY HIGHER VALUES (35-40) FOR FAR SE PORTIONS. THIS HAS THE POTENTIAL TO PRODUCE THE FIRST WIDESPREAD FREEZING TEMPERATURES THIS FALL ACROSS THE LOCAL AREA. A SLOW MODERATING TREND IS EXPECTED MONDAY THROUGH WEDNESDAY AS THE HIGH GRADUALLY MOVES OFFSHORE. HIGHS MONDAY SHOULD RANGE FROM 55-60...WITH MID/UPPER 60S POSSIBLE BY TUESDAY AND WEDNESDAY. OVERNIGHT LOWS SHOULD REMAIN RATHER COOL TUESDAY MORNING RANGING FROM THE LOW/MID 30S INTERIOR TO LOW 40S FOR SE COASTAL LOCATIONS. LOWS SHOULD MODERATE INTO THE MID 40S/LOW 50S WEDNESDAY MORNING WITH THE HIGH WELL OFFSHORE AND THE RESUMPTION OF SSW FLOW. THE NEXT COLD FRONT APPROACHES FROM THE NW WEDNESDAY/WEDNESDAY NIGHT...AND TRACKS THROUGH THE MID ATLANTIC WEDNESDAY NIGHT/THURSDAY. AT THIS TIME MOISTURE APPEARS RATHER LIMITED WITH THIS FRONT...SO ONLY SLIGHT CHC POPS ARE INCLUDED AT THE END OF THE FORECAST PERIOD. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/...
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MOSTLY VFR CONDITIONS WILL PREVAIL ACROSS THE AREA THROUGH FRI EVENING AS A WEAK AREA OF HIGH PRESSURE BUILDS INTO THE AREA TNGT. THE HIGH DISSIPATES OVER THE REGION FRI AFTN WHILE SETTING UP A WEAK WEDGE THAT...DUE TO THE RESULTING NE FLOW...MAY CAUSE SOME MVFR CEILINGS TO OCCUR AT KORF AND KPHF FRI EVENING. ON FRIDAY...A WEAK AREA OF LOW PRESSURE WILL DEVELOP ALONG A STALLED FRONTAL BOUNDARY OFF THE CAROLINA COAST. INCREASING MOISTURE ALONG WITH A FEW SHOWERS MAY IMPACT THE NE NC/SE VA COAST. STRONG UPPER LEVEL SYSTEM WILL MOVE ACROSS THE OH AND THEN TN RIVER VALLEYS FRI INTO SAT. THIS SYSTEM WILL HELP TO FORM A STRONG COASTAL SYSTEM OFF THE OUTER BANKS LATE SAT INTO SUN. AS THIS SYSTEM DEEPENS AND MOVES OFF THE COAST...20-30 KT N WINDS WITH HIGHER GUSTS WILL BE POSSIBLE FROM SAT NIGHT THROUGH SUN AFTN.
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&& .MARINE... WEAK HIGH PRESSURE REMAINS IMMEDIATELY WEST OF THE MID ATLANTIC COAST TONIGHT THROUGH FRIDAY...AS A WAVE OF LOW PRESSURE FORMS OFF THE SOUTHEAST COAST. THIS WILL MAINTAIN NNE FLOW AVERAGING 10-15KT...WITH 2-3FT SEAS AND 1-2FT WAVES IN THE BAY (2-3FT AT THE MOUTH OF THE BAY). THE HIGH WEAKENS FRIDAY NIGHT AS THE FIRST WAVE OF LOW PRESSURE PULLS QUICKLY TO THE NE. A VIGOROUS UPPER LEVEL TROUGH IS EXPECTED TO CROSS THE REGION SATURDAY...WITH A STRONGER AREA OF LOW PRESSURE RAPIDLY DEEPENING OFF THE OUTER BANKS SATURDAY EVENING. THIS WILL BE FOLLOWED BY STRONG CAA LATER SATURDAY NIGHT INTO SUNDAY AS CANADIAN HIGH PRESSURE BUILDS IN FROM THE NW. A NNW WIND IS EXPECTED TO QUICKLY INCREASE LATE SATURDAY AFTERNOON AND A PERIOD OF GALE CONDITIONS IS LIKELY LATE SATURDAY AFTERNOON THROUGH SUNDAY MORNING...FOLLOWED BY SCA CONDITIONS LINGERING THROUGH SUNDAY NIGHT. AT THIS TIME A GALE WATCH HAS BEEN ISSUED FOR ALL ZONES BUT THE RAPPAHANNOCK/YORK/UPPER JAMES BEGINNING LATE SATURDAY AFTERNOON AND RUNNING THROUGH EARLY SUNDAY MORNING FOR THE BAY/SOUND/LOWER JAMES...AND MID-MORNING FOR THE OCEAN. THIS IS RATHER EARLY FOR A GALE WATCH...BUT THE FLAG HAS BEEN RAISED GIVEN A RATHER HIGH CONFIDENCE FORECAST. A RAMP UP SCA HAS BEEN ISSUED FOR THE NRN OCEAN ZONES (N OF PARRAMORE) TO ACCOUNT FOR A LONGER NE PUSH...WHICH COULD BUILD SEAS TO 5-7FT DURING THE DAY SATURDAY. 12Z DATA INDICATES RAPID CYCLOGENESIS OCCURRING OFF THE OUTER BANKS...SO GIVEN THIS THERE IS MUCH LESS OF A CHANCE OF A SHORT DURATION PERIOD OF STORM FORCE GUSTS SATURDAY EVENING. HIGH PRESSURE BUILDS OVER THE AREA SUNDAY NIGHT AND MONDAY AND THEN SLOWLY MOVES OFFSHORE EARLY NEXT WEEK...WITH THE WIND BACKING FROM NW TO SW. && .TIDES/COASTAL FLOODING... LOW PRESSURE IS EXPECTED TO RAPIDLY STRENGTHEN OFF THE COAST LATE SATURDAY AFTERNOON AND SATURDAY NIGHT. TIDAL DEPARTURES OF 1-1.5FT ABOVE NORMAL ARE POSSIBLE SATURDAY NIGHT ALONG THE ATLANTIC COAST AND LOWER BAY. MINOR TIDAL FLOODING IS POSSIBLE IF THE SURGE COINCIDES DURING THE HIGH TIDE CYCLE SATURDAY NIGHT. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...GALE WATCH FROM SATURDAY EVENING THROUGH SUNDAY MORNING FOR ANZ630>634-638. GALE WATCH FROM SATURDAY EVENING THROUGH SUNDAY MORNING FOR ANZ650-652-654-656-658. SMALL CRAFT ADVISORY FROM 7 AM TO 6 PM EDT SATURDAY FOR ANZ650- 652. && $$ SYNOPSIS...MAM NEAR TERM...MAM SHORT TERM...ALB/MAM LONG TERM...AJZ AVIATION...DAP MARINE...AJZ TIDES/COASTAL FLOODING...

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