Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 010757 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 357 AM EDT SAT AUG 1 2015 .SYNOPSIS... HIGH PRESSURE BUILDS INTO THE AREA FROM THE WEST TODAY. A WEAK FRONTAL BOUNDARY SLIDES OFFSHORE LATE SATURDAY INTO SATURDAY NIGHT...BEFORE HIGH PRESSURE RETURNS TO START NEXT WEEK. && .NEAR TERM /THROUGH TONIGHT/... LATEST WX ANALYSIS FEATURES WEAK SFC COLD FRONT IN PLACE FROM NEAR THE COASTAL CAROLINAS INTO THE DEEP SOUTH...WITH ~1018MB SFC HIGH PRESSURE CENTERED FROM THE CENTRAL/SOUTHERN APPALACHIANS BACK INTO THE MID MS RIVER VLY. ALOFT, EARLY MORNING WATER VAPOR IMAGERY AND SUBJECTIVE ANALYSIS DEPICT AN UPPER LEVEL TROUGH CENTERED OVER HUDSON BAY AND EXTENDING SOUTH INTO THE GREAT LAKES REGION INTO THE OH VALLEY/NORTHERN MID-ATLANTIC. DESPITE THE UPR-LEVEL TROUGHING IN PLACE OVER THE EASTERN CONUS, 00Z RAOB ANALYSIS INDICATES PW VALUES ~1 S.D. BELOW NORMAL (0.82" WAL, 0.92 IAD, 0.67" RNK, 0.76" GSO) ACROSS THE REGION. THIS LACK OF LLVL MOISTURE W/SFC HI PRES TO THE WEST SHOULD ALLOW FOR ANOTHER DRY DAY...ALBEIT VERY WARM. LOCAL THICKNESS TOOLS ARE IN GENERAL AGREEMENT WITH MOS GUIDANCE WRT HIGHS, DEPICTING MAXIMA IN THE LOW TO MID 90S UNDER A SUNNY TO MOSTLY SUNNY SKY. WEAK SFC BOUNDARY/TROUGH TO THE SOUTH SLIDES OFFSHORE OF THE SOUTHEAST COAST TONIGHT, AS THE SFC HI PRES CENTER BUILDS IN FROM THE W. LOWS SAT NIGHT AGAIN IN THE MID 60S TO LWR 70S. && .SHORT TERM /SUNDAY THROUGH MONDAY/... UPPER TROUGH REMAINS IN PLACE OVER HUDSON BAY. THIS WILL ALLOW FOR DRY CONDITIONS TO PERSIST FOR SUNDAY AND MONDAY FOR MOST OF THE AREA W/SIMILAR TEMPS WITH THE SFC HI IN PLACE OVER THE AREA. DID INCLUDE A 20% CHANCE OF A TSTM ON SUNDAY, BUT ONLY OVER NE NC WITH SOME SEABREEZE EFFECTS ACTING AS A FOCUS FOR ISO TSRA. ANOTHER SMALL CHC FOR TSRA MONDAY, AS SHORTWAVES ON THE PERIPHERY OF THE UPPER LOW DROP FROM THE OH VLY INTO THE REGION. PW VALUES REMAIN ON THE LOW SIDE, AT OR JUST BELOW SEASONAL NORMAL. THUS, WILL KEEP POP IN SLIGHT CHC RANGE AT MOST FOR NOW. TEMPERATURES ALSO RAMP UP ON MONDAY ON S/SW RETURN FLOW SETUP. EXPECT HIGHS IN THE MID 90S WITH HEAT INDICES PEAKING AOA 100 DEGREES. && .LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/... PATTERN BEGINS WITH WITH A MID/UPPER LEVEL RIDGE CENTERED OVER THE SW/SRN CONUS AND AN UPPER LEVEL LOW NEAR GEORGIAN/HUDSON BAY CANADA. LATEST GFS/ECMWF ARE INTO IMPROVED AGREEMENT COMPARED TO EARLIER RUNS WITH THIS OVERALL SETUP THROUGH THE MIDDLE OF NEXT WEEK. THIS TRANSLATES INTO HOT WX TUE/WED WITH H8 TEMPS RISING TO 19-21 C ACRS THE AREA. WILL FORECAST HIGHS IN THE MID 90S OVER MUCH OF THE AREA...A LITTLE COOLER (HIGHS UPPER 80S TO LOWER 90S) CLOSER TO THE COAST DUE TO SOME POTENTIAL FOR AFTN WINDS SHIFTING MORE TO THE SE/ONSHORE. ALSO A LITTLE COOLER OVER THE FAR NORTH AS SFC FRONT WILL NOT BE THAT FAR NORTH OF THE REGION AND COULD LEAD TO MORE AFTN CLOUDS AND SOMEWHAT HIGHER CHANCES FOR PRECIP. DEW PTS ARE FORECAST BY MODELS TO MIX OUT INTO THE UPPER 50S/LOW 60S WEST OF I- 95 TUE/WED...GENLY STAYED A LITTLE HIGHER THAN THIS...LWR TO MID 60S WEST TO LWR 70S EAST. FOR NOW THIS YIELDS HEAT INDICES PEAKING AROUND 100 F OR A TAD HIGHER BUT REMAINING BELOW 105 F ADVSY THRESHOLDS. AS FOR POPS TUE/WED...MODELS SHOW VERY LITTLE IN THE WAY OF DEEP FORCING/MOISTURE BUT GIVEN FAIRLY LOW H5 HGTS AND HOT LOW LEVELS WILL MAINTAIN AT LEAST A 20% POP BOTH DAYS IN THE AFTN/EVENING TIMEFRAME (UP TO 30% WED ACRS THE NORTH). BY THU/FRI...UPPER RIDGING AMPLIFIES ACRS THE WRN CONUS GRADUALLY CARVING OUT A DEEPER TROUGH OVER THE ERN CONUS. THIS SHOULD BE ENOUGH TO EVENTUALLY DRIVE THE COLD FRONT SOUTH INTO THE MID ATLC/CAROLINAS THU INTO FRI (THOUGH HARD TO SAY IF THE FRONT CLEARS THE AREA ON FRI). RAISED POPS TO 40% N AND 30% S THU AFTN/THU NIGHT...WITH A 20-30% POP FOR FRI. HIGHS TREND DOWN INTO THE MID/UPPER 80S N TO THE LWR 90S S ON THU...AND INTO THE 80S ALL AREAS ON FRI. && .AVIATION /08Z SATURDAY THROUGH WEDNESDAY/... A WEAK TROUGH/FRONTAL BOUNDARY WILL LINGER ALONG THE COAST TODAY... ESPECIALLY ACROSS NE NC. OVERALL CONDITIONS WILL BE VFR WITH LIGHT AND VARIABLE WINDS THROUGH THIS MORNING...BECOMING SLY WITH SPEEDS AOB 10KT BY THIS AFTN WITH SCT CUMULUS AROUND 5 KFT AGL DEVELOPING AT ALL TAF SITES. KECG AND KSBY MAY EXPERIENCE BKN CIGS IN THE AFTN/EVENING AS THE WEAK TROUGH GETS PUSHED OFFSHORE. SKIES GRADUALLY CLEAR OVERNIGHT TONIGHT AS HIGH PRESSURE BUILDS INTO THE MID ATLANTIC REGION THROUGH SUNDAY. ANOTHER TROUGH CROSSES THE AREA ON MONDAY...FOLLOWED BY MORE HIGH PRESSURE. && .MARINE... S-SW WINDS THIS MORNING TURN BACK TO THE SSE BY THIS AFTN WITH SPEEDS AOB 15 KT. GENERALLY LIGHT WINDS AND GOOD BOATING CONDITIONS PREVAIL THROUGHOUT THE WEEKEND WITH SEABREEZES DEVELOPING EACH AFTN. EXPECT LIGHT WEST WINDS IN THE MORNING...TURNING TO THE E/SE AT AROUND 10 KT IN THE LATE AFTN/EVENING. WAVES AVERAGE 1-2 FT IN THE BAY WITH SEAS 2-3 FT. PRESSURE GRADIENT INCREASES MON/MON NIGHT WITH SLY WINDS INCREASING INTO THE 15-20 KT RANGE (POSSIBLY TO MARGINAL SCA CONDS) WITH WAVES 2-3 FT AND SEAS 3-5 FT. HIGH PRESSURE RETURNS TO THE REGION TUESDAY THROUGH WEDNESDAY WITH S-SW WINDS AOB 15 KT AND WAVES 1-2 FT/SEAS 2-4 FT. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...MAM NEAR TERM...MAM SHORT TERM...MAS/MAM LONG TERM...LKB AVIATION...BMD MARINE...BMD

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