Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 170549 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 149 AM EDT THU APR 17 2014 .SYNOPSIS... COOL HIGH PRESSURE SETTLES OVER THE MID ATLANTIC AND NORTHEAST STATES TONIGHT. THE HIGH WILL BECOME CENTERED FROM NEW ENGLAND TO THE CANADIAN MARITIMES THURSDAY AND FRIDAY...MAINTAINING NORTHEAST FLOW AND MUCH COOLER THAN AVERAGE TEMPERATURES ACROSS THE REGION. A COLD FRONT WILL CROSS THE AREA FRIDAY NIGHT WITH HIGH PRESSURE RETURNING FOR SATURDAY. && .NEAR TERM /THROUGH TODAY/... MADE SOME MINOR CHANGES TO FREEZE WARNING...ADDING INLAND WORCESTER MD AND GLOUCESTER/WILLIAMSBURG. OTHERWISE, NPW/FREEZE WARNING REMAINS IN EFFECT UNTIL 13Z. EARLY EVENING WEATHER ANALYSIS FEATURES SFC HIGH PRESSURE CENTERED OVER WESTERN NEW YORK/ERN GREAT LAKES, WITH COLD HIGH PRESSURE RIDGING DOWN OVER THE EASTERN SEABOARD. RESULTANT NE FLOW OFF THE STILL COOL WATERS HAS ALLOWED COASTAL LOCALES TO AVERAGE BETWEEN 3-5 DEG COOLER THAN INLAND SECTIONS, WHERE WINDS ARE LIGHT...AND SHOULD REMAIN SO THROUGH THE OVERNIGHT HOURS. CONSIDERING CLEAR SKY AND LIGHT WINDS, STILL EXPECTING TEMPERATURES WILL DROP INTO THE UPPER 20S AND LOW 30S OVER MOST INLAND SECTIONS (HENCE THE PREVIOUSLY REFERENCED FREEZE WARNING) OVERNIGHT. SEE CLIMO SECTION FOR RECORD LOW TEMP VALUES. TOUGH CALL ACROSS SE PERIPHERY OF WARNING..AND EXPECT SOME AREAS AWAY FROM THE IMMEDIATE COAST RIGHT UP AGAINST NPW WILL (BRIEFLY) FALL INTO THE LOWER 30S BY DAWN. WILL HANDLE THIS WITH A BUFFER AREA HWO MENTIONING NEAR FREEZING TEMPS ACROSS SE VA/NE NC COASTAL PLAIN. HIGH RES MODELS CONTINUE TO SHOW SOME LOW SC PUSHING INLAND ACROSS NC COASTAL PLAIN...AND EVENTUALLY SE VA BY MORNING. HOWEVER, APPEARS MUCH OF THE AREA WILL REMAIN MAINLY CLEAR OVERNIGHT. EARLY MORNING LOWS WL RANGE FROM UPPER 20S FAR WEST...TO UPPER 30S SE COASTAL AREAS. THURSDAY... ON THURSDAY CLOUDS IN ASSOCIATION W/COASTAL TROUGH WILL CONTINUE TO LINGER ACROSS THE SE COAST. ANOTHER CHILLY DAY ON THURSDAY WITH TEMPERATURES IN THE 50S. THE MILDEST TEMPERATURES WILL BE IN WESTERN SECTIONS WHERE A SUNNY SKY PERSISTS FARTHER AWAY FROM THE OCEAN INFLUENCE. && .SHORT TERM /TONIGHT THROUGH SATURDAY/... MODELS AGREE WITH TROUGH DEVELOPING JUST OFF THE SOUTHEAST COAST THURSDAY NIGHT INTO FRIDAY NIGHT IN ASSOCIATION WITH SOME SOUTHERN STREAM ENERGY MOVING ALONG ACROSS THE SOUTHERN US. THIS ENERGY IS NOT WELL HANDLED BY ANY OF THE MODELS, SO PLENTY OF UNCERTAINTY REMAINS. FOR NOW, HAVE LEANED MORE TOWARD THE DRIER NAM BUT WILL BRING SLIGHT CHANCE POPS IN FOR FRIDAY NIGHT OVER THE EASTERN THIRD OF THE AREA, WITH CHANCE POPS OVER PARTS OF NORTHEAST NORTH CAROLINA. TEMPERATURES WILL SLOWLY MODERATE THROUGH THE PERIOD. GENERALLY FOLLOWED MOS GUIDANCE, WHICH KEEPS MOST MINS IN THE 40S THURSDAY NIGHT AND HIGHS ON FRIDAY BACK INTO THE 60S. BY LATE FRIDAY NIGHT ALL MODELS AGREE ON A WEAK COLD FRONT CROSSING THE AREA WITH HIGH PRESSURE REBUILDING FROM THE WEST. THIS WILL CLEAR THE SKIES ACROSS THE AREA AS IT PUSHES THE TROUGH FARTHER OFF THE COAST. LOWS FRIDAY NIGHT WILL BE IN THE 40S WITH HIGH TEMPERATURES ON SATURDAY GETTING BACK TO AROUND NORMAL IN THE LOW 70S. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... A LONG AREA OF HIGH PRESSURE MOVING ACROSS SOUTHEAST CANADA WILL EXTEND INTO THE ERN GREAT LAKES AND OH/TN VALLEYS SAT NIGHT. MEANWHILE...A COASTAL LOW OFF THE SOUTHEAST COAST IS NOW EXPECTED TO STAY SHUNTED WELL SOUTH OF THE AREA SAT NIGHT AND THEN TRACK NE WELL OFF THE CAROLINA COAST THROUGH SUN. THE STRETCHED OUT SFC HIGH AND ASSOCIATED MID/UPPER RIDGING WILL PASS OVER THE MID ATLANTIC REGION SUN INTO EARLY MON. THE SFC HIGH THEN SLIDES OFF THE COAST DURING THE DAY AS THE MID/UPPER RIDGING FLATTENS. A RELATIVELY FLAT (WEST TO EAST ORIENTED) FRONTAL BOUNDARY SAGS DOWN INTO THE AREA MON NIGHT INTO TUE...MOVING OFFSHORE BY WED MORNING. WEAK SHORTWAVE ENERGY AND A SUBSEQUENT SFC LOW TRAVELING ALONG THIS BOUNDARY MAY BRING ANOTHER SHOT OF PRECIPITATION TO THE AREA ON MON/TUE. GFS PRECIP-GENERATION AND GENERAL MOVEMENT CONTINUES TO BE AGGRESSIVE/FAST VERSUS THE ECMWF. HAVE THEREFORE TRIED TO SPLIT THE DIFFERENCE WITH THE POP FORECAST...LEANING TWD SLIGHTLY SLOWER TIMING TO THE ONSET OF PRECIP MON NIGHT AND LIMITING OVERALL COVERAGE ON TUE TO NO HIGHER THAN 40 PERCENT. TEMPERATURES ARE EXPECTED TO BE STRAIGHT-FORWARD SAT NIGHT THROUGH SUN NIGHT AS HIGH PRESSURE CROSSES THE REGION. EXPECT LOWS NEAR NORMAL BOTH NIGHTS IN THE 40S (LOWER 50S POSSIBLE IMMEDIATE SE VA/NE NC COASTS). HIGHS SAT/SUN RANGE FROM ROUGHLY 65 DEGREES FAR NE TO 70 DEGREES SW. AS THE FLAT FRONTAL BOUNDARY STARTS TO SAG INTO THE MID ATLANTIC STATES MON THROUGH WED...THE TEMP FORECAST BECOMES TRICKY IN REGARD TO WHERE EXACTLY THE WARM SECTOR DEVELOPS. WITH PRECIP EXPECTED TO MOVE INTO THE AREA AT SOME POINT MON NIGHT...INCREASING CIRRUS DURING THE DAY MON SHOULD KEEP HIGH TEMPS IN THE UPPER 60S WEST OF I-95 WITH WARMER TEMPS IN THE LOWER 70S EAST OF I-95 (MID-UPPER 60S MD/VA EASTERN SHORE). HIGHS TUE SHOULD BE IN THE LOW-MID 70S INLAND AND IN THE UPPER 60S NEAR THE IMMEDIATE CHES BAY AND ATLANTIC COASTS. THE WARMING TREND CONTINUES WITH HIGHS ON WED IN THE MID 70S INLAND TO UPPER 60S AT THE IMMEDIATE COAST. LOW TEMPERATURES AREAWIDE ON MON/TUE/WED NIGHTS SHOULD ALSO BE WARM WITH READINGS IN THE 50S (OR ABOUT 10 DEGREES ABOVE NORMAL). && .AVIATION /06Z THURSDAY THROUGH MONDAY/...
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A MAINLY CLEAR SKY IS EXPECTED THRU EARLY THIS MORNING. SFC RIDGING FM THE NE WILL THEN HELP TO BRING IN STRATOCU CLOUDS...WHICH COULD GO TO MVFR CIGS...OVER SE VA/NE NC TAF SITES (ORF/ECG) DURING TODAY...DUE TO MOIST ONSHORE FLOW. NE WINDS MAY BE GUSTY ONCE AGAIN AT THESE SITES ALSO FM LATER THIS MORNING INTO THIS EVENG. OUTLOOK...DUE TO CONTINUED RATHER STRONG HI PRES OVER NEW ENGLAND AND THE CANADIAN MARITIMES...THE CHC FOR MVFR CONDITIONS WILL INCREASE THRU FRI NGT...ESPLY ACRS SE PORTIONS. THERE WILL ALSO BE A CHC FOR SHOWERS LATE FRI AND FRI NGT.
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&& .MARINE... SCA FLAGS NOW IN EFFECT THROUGH EARLY THU AFTN FOR ERN VA RIVERS AND NRN CHES BAY...AND THROUGH THU EVENING FOR SRN CHES BAY. AS HIGH PRESSURE SLIDES ACROSS NEW ENGLAND TONIGHT INTO FRIDAY... WINDS TURN TO THE NE AND ANOTHER PUSH OF COLD AIR (ALBEIT WEAKER) IS ANTICIPATED TO OCCUR OVERNIGHT INTO EARLY THU AFTN...WHICH WILL INCREASE SPEEDS INTO SCA THRESHOLDS DURING THIS TIME. ALSO...THE PERSISTENT ONSHORE FLOW WILL CAUSE SEAS TO REMAIN AT OR ABOVE 5 FT FOR ALL COASTAL WATERS THROUGH FRI EVENING. PROLONGED SCA FLAGS ARE NOW IN EFFECT FOR THE COASTAL WATERS DURING THIS TIMEFRAME BUT WILL LIKELY BE EXTENDED THROUGH SAT DUE TO SEAS STAYING AT OR ABOVE 5 FT IN PERSISTENT NE/ONSHORE FLOW. THE NEXT BEST CHANCE FOR SCA CONDITIONS APPEARS TO BE SAT NIGHT INTO SUN MORNING AS A WEAK LOW PASSING ACROSS NRN NEW ENGLAND PUSHES A WEAK BACKDOOR TROUGH AND A COOLER AIRMASS ACROSS THE WATERS. WIND DIRECTION REMAINS IN AN ONSHORE DIRECTION AND SEAS COULD BRIEFLY REACH ABOVE 5 FT AGAIN. && .CLIMATE... RECORD LOW MAXIMUM TEMPERATURES TODAY 4/16 (AND UNOFFICIAL HIGHS): RIC...45 (1929) (UNOFFICIAL HIGH 53) ORF...46 (1935) (47) SBY...45 (1935) (51) ECG...52 (1962 & 1952) (50) RECORD LOWS FOR THU 4/17: RIC...31 (1949) ORF...34 (1875) SBY...26 (2008) && .AKQ WATCHES/WARNINGS/ADVISORIES...
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MD...FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR MDZ021>024. NC...FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR NCZ012. VA...FREEZE WARNING UNTIL 9 AM EDT THIS MORNING FOR VAZ048-049- 060>085-087>090-092. MARINE...SMALL CRAFT ADVISORY UNTIL 8 PM EDT FRIDAY FOR ANZ633-650-652- 654-656-658. SMALL CRAFT ADVISORY UNTIL 1 PM EDT THIS AFTERNOON FOR ANZ630- 631-635>638. SMALL CRAFT ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR ANZ632-634.
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&& $$ SYNOPSIS...JAB NEAR TERM...MAM/JAB SHORT TERM...JAB LONG TERM...BMD AVIATION...TMG MARINE...BMD CLIMATE...AKQ

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