Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 281010 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 510 AM EST WED JAN 28 2015 .SYNOPSIS... HIGH PRESSURE SLOWLY BUILDS EAST INTO THE MID ATLANTIC REGION THROUGH TONIGHT. THE HIGH SLIDES OFFSHORE THURSDAY...BEFORE A COLD FRONT CROSSES THE AREA THURSDAY NIGHT. COLD HIGH PRESSURE THEN RETURNS FOR LATE FRIDAY INTO SATURDAY. && .NEAR TERM /THROUGH TONIGHT/... LATEST WX ANALYSIS FEATURES STRONG COASTAL LOW (~989MB) LIFTING INTO THE GULF OF MAINE/BAY OF FUNDY AREA TOWARDS ATLANTIC CANADA EARLY THIS MORNING. TO THE WEST, ~1026MB SFC HIGH PRESSURE CONTINUES TO DRIFT EAST OVER THE OHIO VALLEY, AND IS FORECAST BUILD ACROSS THE LOCAL AREA TODAY INTO TONIGHT. DID NUDGE TEMPERATURES UP SLIGHTLY EARLY THIS MORNING WITH WINDS KEEPING TEMPS UP ABOVE GUIDANCE, BUT DO EXPECT WINDS TO DROP OFF BRIEFLY JUST BEFORE DAWN...AND IN THE DRY AIRMASS IN PLACE, EXPECT READINGS TO DROP OFF QUICKLY JUST BEFORE SUNRISE. THICKNESS TOOLS MESH WELL WITH THE GOING FORECAST, WITH EXPECTED HIGHS TODAY IN THE LOWER TO MIDDLE 40S ACROSS MUCH OF THE AREA, WITH SLIGHTLY COOLER UPR 30S OVER THE EASTERN SHORE. CONDITIONS WL REMAIN A BIT BREEZY THROUGH THE AFTN, WITH NORTHERLY WINDS AVGG 15-20 MPH (GUSTS TO 25) ALONG THE COAST, 5-10 MPH INLAND. THIS WILL KEEP WIND CHILLS IN THE 30S THROUGH THE DAY FOR MOST DESPITE A SUNNY TO MOSTLY SUNNY SKY. HIGH PRESSURE MOVES OVERHEAD TONIGHT/ERY THURSDAY. CLEAR SKIES AND LIGHT WINDS SHOULD YIELD GOOD RADIATING CONDITIONS AND A COLDER NIGHT TNGT. EARLY MORNING LOWS THURSDAY MORNING 15 TO 20 INLAND TO LOWER TO MID 20S ALONG THE COAST. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... HIGH PRESSURE PUSHES OFFSHORE THURSDAY MORNING, ALLOWING SOUTHERLY FLOW TO RETURN AHEAD OF NORTHERN STREAM SHORT WAVE AND ASSOCIATED COLD FRONT. NOT MUCH MOISTURE FOR THE SYSTEM TO WORK WITH AS IT CROSSES THE OHIO VALLEY TOWARDS THE CENTRAL APPALACHIANS THU AFTN/EVENING, OWING TO DOWNSLOPE FLOW ACROSS THE REGION. THUS, HAVE KEPT A DRY FORECAST FOR MOST OF THE AREA ON THU...WITH ONLY A SLIGHT CHC TO LOW CHC (20-30%) CHANCE FOR SOME PASSING RAIN SHOWERS, MAINLY ALONG AND NORTH OF THE RICHMOND METRO AREA. ANY SHRAS LATE THU AFTN/EVENING WOULD BE BRIEF, WITH QPF ON THE ORDER OF A FEW HUNDREDTHS AT BEST. 00Z/28 DATA IS ALSO A BIT QUICKER TO DRY OUT ANY PCPN OVER THE EASTERN SHORE, SO WILL GO WITH A DRY FORECAST OVERNIGHT. FOR HIGHS, PRE-FRONTAL SW FLOW YIELDS A MODEST AND SHORT LIVED WARM UP ON THU, WITH HIGHS INTO THE MID TO UPPER 40S (WARMEST I-85/US-1 CORRIDOR). ASSOCIATED SFC COLD FRONT CROSSES THE AREA LATE THU NGT/FRIDAY MORNING, USHERING IN A SHARPLY COLDER AND DRIER AIRMASS FOR FRIDAY INTO THE WEEKEND. LOOK FOR BRISK WINDS OUT OF THE NW THROUGH THE DAY ON FRIDAY INTO FRIDAY NIGHT TO YIELD WIND CHILLS IN THE 20S DURING THE DAY FRIDAY AND INTO THE LOW TEENS FRIDAY NIGHT (SINGLE DIGITS TO NEAR ZERO ON THE LOWER EASTERN SHORE). && .LONG TERM /SATURDAY THROUGH TUESDAY/... NRN STREAM REMAINS ACTIVE DURING THE EXTENDED PERIOD WITH BELOW NORMAL TEMPS PREVAILING. TROUGH EXITS THE COAST FRI NIGHT/SAT MORNING...AS COLD CANADIAN HIGH PRESSURE CONTINUES TO BUILD OVER THE MID-ATLANTIC DURING THE DAY SAT. THE RESULT WILL BE MOSTLY SUNNY SKIES AND TEMPS IN THE LOW-MID 30S. H85 TEMPS PROGGED TO BE AROUND -10C (-1 STD DEV). THEREAFTER...MODELS IN GOOD AGREEMENT NOW WITH PUSHING THE SFC HIGH OFFSHORE SUN AS THE NEXT NRN STREAM SHORTWAVE DIGS INTO THE SOUTHERN STATES. ASSOCIATED SFC LOW PROGGED TO LIFT FROM THE LOWER MS VALLEY NEWD OVER THE CENTRAL APPALACHIANS SUN...AND NORTH OF THE REGION SUN NIGHT. TRAILING COLD FRONT PROGGED TO CROSS THE REGION SUN NIGHT. DEEP H85 TROUGH EXPECTED TO ADVECT MOISTURE NWD FROM THE ERN GULF INTO THE REGION IN ADVANCE OF THE FRONT. COMBINED WITH HEIGHT FALLS AND INCREASING WINDS ALOFT...WIDESPREAD PRECIP IS EXPECTED TO OVERSPREAD MUCH OF THE AREA LATE SUN INTO SUN NIGHT. RETURN FLOW WILL WARM TEMPS INTO THE LOW-MID 40S (POSSIBLY WARMER) SUN...WITH THE COLDEST AIR REMAINING OVER THE GREAT LAKES REGION. THE RESULT WILL BE PREDOMINATELY RAIN...BUT A BRIEF RAIN/SNOW MIX IS POSSIBLE AT THE ONSET AS WAA KICKS IN. HOWEVER...NO ACCUMULATION IS EXPECTED. ALL RAIN LATE SUN-SUN NIGHT...WITH A POSSIBLE CHANGE OVER ACROSS THE NRN ZONES LATE SAT NIGHT AS COLD AIR PUNCHES INTO THE REGION. WLY PUSH BEHIND THE SHORTWAVE WILL RESULT IN DRYING CONDITIONS MON- TUES AS COLD CANADIAN HIGH PRESSURE BUILDS IN FROM THE NW. BY TUES...TEMPS FORECAST TO BE BACK INTO THE MID-UPPER 30S. && .AVIATION /10Z WEDNESDAY THROUGH SUNDAY/... REMNANT BKN-OVC CLOUDS AROUND 10 KFT AGL WILL CONTINUE TO SLIDE SWD AND OUT OF THE AREA BY 28/0900-1000Z...BECOMING MOSTLY CLEAR THEREAFTER. HIGH PRESSURE BUILDS INTO THE REGION TODAY AND OVERHEAD WEDNESDAY NIGHT...THEN SLIDES OFF THE SOUTHEAST COAST ON THURSDAY. ALTHOUGH VFR CONDITIONS WILL PREVAIL DURING THE NEXT 24 HOURS...THERE WILL BE JUST ENOUGH OF A SFC PRESSURE GRADIENT BTWN THE INCOMING HIGH AND THE COASTAL LOW OFF THE NRN NEW ENGLAND COAST TO PRODUCE BREEZY NNW-N WINDS THROUGH TODAY. WINDS DIMINISH AROUND SUNSET THIS EVENING AS HIGH PRESSURE TAKES HOLD. A CLIPPER SYSTEM SKIRTS JUST NORTH OF THE AREA LATE IN THE DAY THURSDAY INTO THURSDAY NIGHT...DRAGGING A COLD FRONT ACROSS THE REGION LATE THURSDAY NIGHT. THE BEST CHANCE FOR LIGHT PRECIPITATION (RAIN CHANGING TO SNOW) WILL BE GENERALLY NORTH OF INTERSTATE 64 THURSDAY EVENING. A GOOD SHOT OF COLD AIR BEHIND THE FRONT IS THEN EXPECTED TO BRING ANOTHER ROUND OF BREEZY WINDS TO THE AREA ON FRIDAY AS CANADIAN HIGH PRESSURE BUILDS INTO AND SETTLES OVER THE MID ATLANTIC REGION THROUGH MOST OF THE DAY ON SUNDAY. A SOUTHERN STREAM LOW PRESSURE IS ANTICIPATED TO TRACK INTO THE AREA FROM THE SOUTHWEST LATE SUNDAY INTO MONDAY. && .MARINE... COASTAL LOW LOCATED OFF THE MAINE AND NOVA SCOTIA COASTS WILL PUSH OUT TO SEA TODAY AS HIGH PRESSURE BUILDS INTO THE REGION TODAY. THERE IS STILL JUST ENOUGH OF A PRESSURE GRADIENT BTWN THESE SYSTEMS TO KEEP BREEZY NW WINDS OVER THE WATERS TODAY THROUGH THIS EVENING. SPEEDS WILL AVERAGE 15-25KT. GUSTS UP TO 30KT WILL PERSIST ON THE BAY THROUGH THIS MORNING...AND ON THE COASTAL WATERS ALL DAY. SEAS CURRENTLY RANGE FROM 5-8FT NORTH TO 7-10FT SOUTH AND ARE EXPECTED TO SLOWLY SUBSIDE TODAY INTO TONIGHT... DROPPING BELOW 5FT LATE TONIGHT. WAVES OF 3-5FT WILL ALSO SUBSIDE TO 3-4FT THROUGH TODAY...DROPPING TO 2-3FT BY LATE THIS EVENING. SCA FLAGS REMAIN IN EFFECT THROUGH THIS EVENING. HIGH PRESSURE MOVES OVER THE WATERS TONIGHT...ALLOWING WINDS TO DIMINISH AOB 15KT AS THE PRESSURE GRADIENT FINALLY RELAXES. THE HIGH GETS SHUNTED OVER THE SE COAST THU AS A CLIPPER SYSTEM APPROACHES THE MID ATLANTIC REGION. THE COLD FRONT ASSOCIATED WITH THE CLIPPER IS EXPECTED TO CROSS THE WATERS LATE THU NIGHT. A SUBSTANTIAL INCREASE IN WIND SPEEDS SHOULD BE ANTICIPATED PRIMARILY DURING FRI/FRI NIGHT AS A COLD CANADIAN AIRMASS GETS PULLED OVER THE WATERS BY THE DEPARTING LOW AND A CANADIAN HIGH BUILDING INTO THE REGION. MODELS HAVE TRENDED COLDER WITH REGARD TO THE AIRMASS TEMPERATURES THUS RESULTING IN STRONGER CAA PROCESSES. SINCE MODELS TEND TO UNDERCUT WIND SPEEDS IN THESE SITUATIONS...DECIDED TO GO ABOVE GUIDANCE WHICH PUTS THE WATERS WITHIN POTENTIALLY SOLID GALE CONDITIONS (EXCEPT RIVERS/SOUND) FRI/FRI NIGHT. NW WINDS WOULD AVERAGE 20-25KT WITH GUSTS OF 35-40KT. SEAS/WAVES ALSO EXPECTED TO BUILD QUICKLY ONCE THE WIND SURGE BEGINS. SEAS COULD REACH 7-10FT...WAVES COULD REACH 4-6FT. WILL NEED TO KEEP A CLOSE EYE ON MODEL TRENDS FOR POTENTIAL HEADLINES IN THE POST-FRONTAL ENVIRONMENT. REGARDLESS OF STRENGTH... CONDITIONS WILL BEGIN TO SUBSIDE/DIMINISH SAT NIGHT AS THE CANADIAN HIGH SLIDES DIRECTLY OVER THE WATERS. A SOUTHERN STREAM LOW PRESSURE SYSTEM IS ANTICIPATED TO TRACK INTO THE AREA FROM THE SOUTHWEST LATE SUN INTO MON. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR ANZ630>638. SMALL CRAFT ADVISORY UNTIL 4 AM EST THURSDAY FOR ANZ650-652- 654-656-658. && $$ SYNOPSIS...MAM NEAR TERM...MAM SHORT TERM...MAM LONG TERM...SAM AVIATION...BMD MARINE...BMD

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