Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 040918 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 418 AM EST WED MAR 4 2015 .SYNOPSIS... A WARM FRONT LINGERS OVER THE NORTHERN MID ATLANTIC EARLY TODAY...WITH A COLD FRONT SLOWLY CROSSING THE REGION LATER THIS AFTERNOON THROUGH TONIGHT. THE FRONT WILL STALL OVER NORTH CAROLINA ON THURSDAY...WITH A WAVE OF LOW PRESSURE MOVING ALONG THE FRONT INTO THURSDAY NIGHT. THIS WILL BRING ANOTHER ROUND OF WINTRY WEATHER TO THE AREA...FOLLOWED BY COLD AND DRY CONDITIONS BY FRIDAY. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... THE CURRENT SURFACE ANALYSIS SHOWS A WARM FRONT LINGERING OVER THE NRN MID-ATLANTIC WITH A RESIDUAL WEDGE AIRMASS IN PLACE TO THE LEE OF THE MOUNTAINS. ONE BATCH OF RA HAS MOVED OFF THE COAST EARLY THIS MORNING...WITH ANOTHER AREA OF RA FROM THE NRN DELMARVA BACK ACROSS NRN VA AND INTO THE MOUNTAINS. THIS WILL SKIRT NRN PORTIONS OF THE AREA THIS MORNING...WITH OTHER AREAS GENERALLY RAIN-FREE. STRATUS WILL LINGER THROUGH AT LEAST MID-MORNING...WITH AREAS OF FOG...ESPECIALLY OVER SE VA/NE NC. HIGH TEMPERATURES WILL BE VERY CHALLENGING TODAY. THERE IS A POTENTIAL THAT FAR NRN PORTIONS STAY IN THE UPPER 40S...WITH LOW 70S ACROSS SRN PORTIONS. CENTRAL PORTIONS COULD EXPERIENCE A SPREAD OF AT LEAST 10-15F DEPENDING ON THE EVENTUAL POSITION OF THE FRONTAL BOUNDARY. && .SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY/... A COLD FRONT PRESENTLY BACK OVER THE OHIO VALLEY DROPS INTO THE AREA THIS EVENING AND TRACKS NNW-SSE ACROSS THE AREA OVERNIGHT INTO THU MORNING. MEANWHILE...A WAVE OF LOW PRESSURE DEVELOPS ALONG THE FRONT AND TRACKS ACROSS THE CAROLINAS WEDNESDAY NIGHT INTO THURSDAY. MUCH COLDER AIR ARRIVES BEHIND THE FRONT WITH MOST OF THE AREA FALLING INTO THE UPPER 20S/LOW 30S BY THU AFTN. FORECAST SOUNDINGS SHOW DRY AIR LINGERING BETWEEN 600-400MB TONIGHT...SO ANY PCPN (IN THE FORM OF -RA) WILL BE LIGHT. A STRONG ANTI-CYCLONIC JET IS PRESENTLY LOCATED FROM THE MID-MISSISSIPPI VALLEY THROUGH ATLANTIC CANADA. THIS JET STRUCTURE WILL TRANSLATE EWD THROUGH THU AS A STRONG TROUGH DIGS ACROSS THE UPPER MIDWEST AND GREAT LAKES BY LATER THU MORNING INTO THU AFTERNOON. IT IS AT THIS TIME THAT DEEPER MOISTURE WILL ARRIVE AND RRQ FORCING WILL BE IDEALIZED AND TRIGGER THE ONSET OF WINTRY PCPN FROM NW-SE ACROSS THE AREA. IT IS NOT UNTIL 21Z THU TO 00Z FRI THAT SUB 1540M 850-700MB THICKNESS VALUES ARRIVE INTO NW PORTIONS OF THE AREA. HOWEVER...BY THIS TIME THE STRONGEST UVM WILL BE EXITING THE COAST. OVERALL IT APPEARS THAT SLR VALUES WILL BE LOW (PERHAPS 5:1-8:1) GIVEN THAT THERE WILL BE A PERIOD OF SLEET...AND THAT MID-LEVEL THICKNESSES WILL BE `WARM` DURING THE STRONGEST FORCING. THE CURRENT FORECAST HAS A NARROW BAND OF 3-4" FROM LOUISA COUNTY TO DORCHESTER COUNTY BORDERED BY A BAND OF 2-3" FOR OTHER PORTIONS OF THE NW PIEDMONT...NRN NECK...AND LOWER MD EASTERN SHORE. CURRENTLY 1-2" IS FORECAST FROM THE RIC METRO DOWN THROUGH HAMPTON ROADS...WITH 1" OR LESS FARTHER S. A BRIEF PERIOD OF FZRA IS POSSIBLE DURING THE TRANSITION FROM RA TO SN/IP WITH ANY ICE ACCUM ONLY TRACE TO A FEW HUNDREDTHS OF AN INCH. CONFIDENCE IS NOT HIGH ENOUGH FOR A WATCH ACROSS THE FAR N AT THIS TIME GIVEN THAT THIS IS A LATER THIRD PERIOD EVENT...SO THIS WILL CONTINUED TO BE HIGHLIGHTED IN THE HWO. WINTRY PCPN SHOULD TAPER OFF THU EVENING...WITH DRIER AIR ARRIVING FROM THE NW DURING THE LATE EVENING. TEMPERATURES WILL CONTINUE TO PLUMMET WITH LOWS FRI MORNING RANGING FROM THE LOW TEENS NW...TO LOW 20S SE. HIGHS FRI WILL STRUGGLE TO REACH 30-35 FRI UNDER A MOSTLY SUNNY SKY. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... EXTENDED PERIOD WILL BE HIGHLIGHTED BY GENERALLY DRY CONDITIONS AND A RETURN TO NEAR SEASONABLE NORMAL TEMPS. MEDIUM RANGE GUIDANCE IN GENERAL CONSENSUS WITH THE UPPER FLOW THRU THE EXTENDED...CHARACTERIZED BY RIDGING/BLOCKING OVER THE WRN CONUS/ERN PACIFIC AND BROAD TROUGHING OVER THE CNTRL AND ERN CONUS. TO BEGIN THE PERIOD...COLD/DRY 1030+MB ARCTIC HIGH PRESSURE CENTERS OVER THE MID-ATLANTIC REGION. THURSDAYS COLD FRONT LOCATES OFF THE COAST...EXTENDING SWWD INTO THE NRN GULF. H85 TEMPS DROP TO AROUND -8C FRI (~-1 STD DEV)...SLIGHTLY WARMER THAN DEPICTED 24 HRS AGO. HIGHS FRI GENERALLY IN THE LOW-MID 30S INLAND AND UPPER 20S-LOW 30S COASTAL AREAS. AIRMASS MODIFIES FRI NIGHT-SAT AS THE COLD/DRY AIR RETREATS NWD. HIGH PRESSURE REMAINS OVER THE REGION SAT...WITH LIGHT RETURN FLOW HELPING TO MODERATE LOW LEVEL THICKNESSES. TEMPS WARM INTO THE UPPER 40S-LOW 50S INLAND AND LOW- MID 40S COASTAL AREAS. SKY AVG MOSTLY SUNNY-PARTLY CLOUDY. HIGH PRESSURE REMAINS OVER THE REGION SUN...RESULTING IN CONTINUED DRY AND WARMING CONDITIONS. HIGHS IN THE LOW-MID 50S INLAND AND LOW 40S TO UPPER 40S COASTAL AREAS. ATTENTION THEN TURNS OUT WEST...WHERE MODELS CONTINUE TO STRUGGLE HANDLING SPLIT/BLOCKY FLOW AND SRN STREAM ENERGY OVER THE DESERT SW/BAJA. GOOD NEWS IS THAT NOW THE DETERMINISTIC ECMWF HAS TRENDED DRY SUN NIGHT-EARLY NEXT WEEK...MATCHING THE GFS AND ENSEMBLES. HOWEVER...SPLIT FLOW CONTINUES RESULTING IN LOW CONFIDENCE EARLY NEXT WEEK. FRONT OVER THE GULF WILL ATTEMPT TO AMPLIFY AND LIFT NWD AS SRN STREAM ENERGY APPROACHES...BUT WILL KEEP POPS SILENT. HIGHS EARLY NEXT WEEK (MON AND TUES) CONTINUE TO WARM INTO THE MID 50S INLAND AND LOW-UPPER 40S COASTAL AREAS THANKS TO COLD WATER. && .AVIATION /09Z WEDNESDAY THROUGH SUNDAY/... AS OF 06Z...THE SURFACE MAP SHOWS A WARM FRONT REACHING FROM WRN PA AND SNAKING S/SW ACROSS ERN WV. A COLD FRONT FROM A LOW OVER THE GREAT LAKES EXTENDS DOWN ACROSS OH AND KY. THE MID ATLANTIC STATES WILL BECOME LARGELY WARM SECTORED LATER TODAY INCLUDING ALL THE TAF SITES EXCEPT SBY. PCPN HAS BEEN SPARSE AND SUPPORT FOR MORE THAN LIGHT DRIZZLE OR BRIEF SHOWERS IS NOT PRESENT. HAVE LIMITED THE PCPN IN THE TAFS COMPARED WITH WHAT IS IN THE NAM MOS. THE BEST CHANCE FOR RAIN IS AT SBY THROUGHOUT THIS AFTN. WINDS WILL BE FROM THE S/SW OVERNIGHT AND SW TODAY AND BECOME GUSTY AT TIMES...ASIDE FROM SBY WHERE WINDS SHOULD STAY UNDER 10 KNOTS. OUTLOOK...RAIN INCREASES FROM THE NORTH TONIGHT AND ON THURSDAY BECOMES MIXED PCPN OVER NRN PORTIONS. BY LATE IN THE DAY...PCPN BECOMES SNOW NRN PORTIONS AND MIXED PCPN SRN PORTIONS. PCPN BECOMES MAINLY SNOW THURSDAY EVENING BEFORE ENDING FROM THE NW. ANY SNOW ACCUMULATIONS ARE EXPECTED TO BE AROUND 2 INCHES RIC AND SBY AND AROUND AN INCH SE PORTIONS. A GUSTY NORTHERLY WIND WILL DEVELOP ALONG THE COAST THURSDAY. HIGH PRESSURE SETTLES WITH DRY WEATHER FRIDAY THROUGH SUNDAY. && .MARINE... A COLD FRNT APPROACHES FM THE W TDA WITH S/SW FLOW CONTINUING OUT AHEAD OF THE FRNT. WINDS MAY COME CLOSE TO SCA THRESHOLDS THIS MORNG OVER THE LWR BAY DUE TO A STRONG LLJ...BUT WAA AND COLD WATERS WILL CAUSE A SHARP INVERSION THAT SHOULD KEEP SUSTAINED WINDS UP TO ~15 KT THERE. ISSUED A DENSE FOG ADVSRY FOR CSTL WTRS S OF CAPE CHARLES LIGHT DUE TO EXPECTED VSBYS AOB 1 MI THRU THE MIDDAY HRS IN ASSOCIATION WITH VERY MOIST LO LEVELS. THE FRNT SLOWLY DROPS THRU THE AREA LATE TDA INTO TNGT AS A WAVE OF LO PRES DEVELOPS ALONG THE FRNT. AS THE FRNT FINALLY PUSHES S OF THE AREA TNGT...SCA CONDS WILL COMMENCE OVR THE WTRS. THESE CONDS WILL CONTINUE INTO THU NGT AS WELL SO EXTENDED THE HEADLINES INTO THE 4TH PERIOD. WINDS MAY COME CLOSE TO GALE FORCE OVR SRN CSTL WTRS BUT CONFIDENCE IS NOT HI ENUF TO ISSUE A GALE WATCH/WARNG ATTM. ALSO KEPT ALL RIVER ZONES EXCEPT THE LWR JAMES OUT OF THE ADVSRY FOR NOW BUT WILL CONTINUE TO MONITOR. WAVES OVER THE BAY UP TO 4-5 FT WITH SEAS OVER CSTL WTRS UP TO 7-8 FT. SFC HI PRES THEN BLDS IN FOR FRI INTO THE WEEKEND LEADING TO IMPROVING MARINE CONDS. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 4 AM THURSDAY TO 4 AM EST FRIDAY FOR ANZ630>632-634-650-652-654-656-658. DENSE FOG ADVISORY UNTIL NOON EST TODAY FOR ANZ633-656-658. SMALL CRAFT ADVISORY FROM 7 AM THURSDAY TO 4 AM EST FRIDAY FOR ANZ633-638. && $$ SYNOPSIS...AJZ/LKB NEAR TERM...AJZ SHORT TERM...AJZ LONG TERM...SAM AVIATION...MAS/LSA MARINE...MAS

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