Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 232100 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 400 PM EST FRI JAN 23 2015 .SYNOPSIS... LOW PRESSURE OVER THE GULF COAST REGION WILL RAPIDLY LIFT NORTHEAST ALONG THE SOUTHEAST ATLANTIC COAST TONIGHT...AND PUSH OFF THE MID ATLANTIC COAST ON SATURDAY. HIGH PRESSURE RETURNS BRIEFLY ON SUNDAY...TO BE FOLLOWED BY LOW PRESSURE FROM THE NORTHWEST CROSSING THE REGION SUNDAY NIGHT THROUGH MONDAY. && .NEAR TERM /THROUGH SATURDAY/... CURRENT ANALYSIS REVEALING DEEPENING SFC LOW PRESSURE CENTERED ALONG THE AL/GA GULF COAST REGION...WITH SFC HIGH OFF THE DELMARVA COAST. WSW FLOW PREVAILS ALOFT WELL OUT AHEAD OF AMPLIFYING MID/UPPER LEVEL TROUGH ALONG THE GULF COAST. PRECIP SHIELD HAS OVERSPREAD MUCH OF THE CWA...BUT DRY AIR IN LOW LEVELS HAS KEPT THE PRECIP ON THE LIGHT SIDE THUS FAR (JUST A FEW HUNDREDTHS THROUGH 20Z). THIS DRY AIR HAS ALSO ALLOWED THE RAIN TO BE MIXING WITH SLEET WITH SFC TEMPERATURES AS HIGH AS 40 F (AND DEW PTS IN THE 20S). NO IMPACTS WILL OCCUR AS THE DEW PTS ARE NOT LOW ENOUGH TO COOL THE TEMPS DOWN TO BELOW FREEZING (GENLY EXPECTING TEMPS TO DROP TO 33-36 F ALONG/WEST OF I-95 AND ACRS THE NRN TIER OF ERN VA AND THE MD ERN SHORE THROUGH EARLY EVENING. FOR TONIGHT...MAIN CONCERN WILL NOT BE WINTRY PRECIP...BUT RATHER THE POTENTIAL FOR MODERATE TO HEAVY RAIN. FOLLOWING A BLEND OF WPC AND SREF GUIDANCE FOR RAIN OVERNIGHT YIELDS TOTALS OF 1.00 TO 1.50" THROUGH 12 Z...WITH AN ADDITIONAL 0.25-0.50" EXPECTED DURING THE DAY SAT. THIS AS STRONG UPPER JET/RRQ FORCING INCREASES DEEP UVM LATER THIS EVENING AND OVERNIGHT. GFS/NAM PROG ~60 KT SOUTHERLY LOW LEVEL JET BETWEEN 900-800 MB FROM 03-06Z...AND AS SFC LOW SLIDES OFF THE NC/SE VA COAST BETWEEN 06-12Z WILL SEE RAPID CYCLOGENESIS AND PRESSURE FALLS. HAVE ADDED MENTION OF HEAVY RAIN TO ALL AREAS...HIGHEST CONFIDENCE ACRS THE SE ZONES...THOUGH SOME OF THE MODELS ARE SHOWING A SECONDARY AREA OF HEAVY RAIN OVER NW SECTIONS DUE TO FRONTOGENESIS. TEMPS OVERNIGHT WILL BE STEADY IN THE MID-UPPER 30S MOST AREAS...BUT WILL LIKELY RISE A BIT THROUGH THE 40S OVER FAR SE VA/NE NC. DRY SLOT ENTERS AREAS WEST OF I-95 PRIOR TO DAYBREAK SO WILL RAMP POPS DOWN AFTER 06Z-09Z THERE. GIVEN TRACK OF SFC LO PRES ON MDLS THROUGH CSTL NE NC THEN OUT TO SEA...CONCERN ON SAT WILL BE DRY SLOT ARRIVING FM THE SW...RESULTING IN BULK OF PCPN WINDING DOWN/ENDING BEFORE ANY AIR COLD ENOUGH FM THE PCPN ENDING AS MIXED SN/RA OR ALL SN (IN THE AFTN/EVE). GFS/NAM/ECMWF ALL SHOW A BRIEF PERIOD OF STRONGER FORCING AS THE UPPER SYSTEM PUSHES THROUGH THE REGION SAT AFTN. WHILE BNDRY LAYER WOULD BE FAIRLY WARM...COULD SEE A BRIEF PERIOD WHERE PRECIP COULD TURN TO SNOW OR RAIN/SNOW MIX IN HIGHER PRECIP RATES. THUS WILL KEEP MENTION OF RA/SN IN BY AFTN ACRS N/W 1/2 OF THE CWA GIVEN THE UNCERTAINTY. HIGHS SAT IN THE UPR 30S TO MID 40S (ARND 50 F CSTL NE NC). && .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/... LATEST 12Z SUITE OF THE GFS/NAM/ECMWF CONTINUE TO TREND FASTER/MORE PROGRESSIVE AND THE W/NW FLOW ALOFT SHOULD ALLOW FOR RAPID DRYING OF ANY LEFTOVER MOISTURE. WILL FORECAST DRY CONDITIONS UNDER PARTLY CLOUDY TO MOSTLY CLEAR SKIES SAT NIGHT OTHER THAN A CHC FOR SNOW BRIEFLY IN THE EVENING ON THE MD ERN SHORE/NRN NECK. LOWS 30-35 F. PARTLY SUNNY WITH HIGHS IN THE LWR 50S S TO THE MID 40S N ON SUN IN ADVANCE OF NEXT CLIPPER SYSTEM. MUCH COLDER AIRMASS APPROACHES FROM THE WNW SUN NIGHT INTO MON...WILL CARRY HIGH CHC TO LIKELY POPS AND RAIN CHANGING TO SNOW ON MON. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... && .AVIATION /21Z FRIDAY THROUGH WEDNESDAY/... A LOW PRESSURE SYSTEM DEVELOPING OVER THE SOUTHEASTERN US WILL SLIDE NE THIS AFTERNOON AND TONIGHT. THIS WILL PUSH GULF MOISTURE INTO THE AREA AND OVER RUN COOL DRY AIR AS HIGH PRESSURE EXITS THE REGION. WILL GRADUALLY SEE CONDITIONS DETERIORATE LATE THIS AFTERNOON AND TONIGHT FROM VFR TO IFR/LIFR OVERNIGHT WITH LOW CEILINGS AND REDUCE VISIBILITIES. BY SATURDAY MORNING...THE SFC LOW WILL BE OFF THE DELMARVA COAST AND SHOULD BEGIN TO RAPIDLY INTENSIFY. THIS WILL TURN THE WINDS MORE NORTH AND NORTHWEST DURING THE DAY AND PULL THE REMAINING MOISTURE OFF THE COAST. AS THE UPPER LOW PULLS ACROSS THE AREA SATURDAY AFTERNOON...SOME OF THE LINGERING SHOWERS COULD CHANGE TO SNOW...WHICH WOULD CAUSE MORE MVFR TO IFR CONDITIONS. ONCE THE MOISTURE CLEARS SAT EVENING...WILL SEE A RETURN TO VFR CONDITIONS SAT NIGHT THROUGH SUNDAY. ANOTHER WEATHER SYSTEM WILL IMPACT THE AREA MONDAY INTO TUESDAY. THIS COULD AGAIN CAUSE SOME MVFR TO IFR CEILINGS ALONG WITH A CHANCE FOR SOME WINTRY PRECIPITATION...MOST LIKELY RAIN SHOWERS CHANGING TO SNOW SHOWERS LATER MONDAY INTO TUESDAY. && .MARINE... && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 7 AM TO 7 PM EST SATURDAY FOR ANZ635>638. SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 7 PM EST SATURDAY FOR ANZ630>634. SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO 1 AM EST SUNDAY FOR ANZ654-656-658. SMALL CRAFT ADVISORY FROM 1 AM SATURDAY TO 4 AM EST SUNDAY FOR ANZ650-652. && $$ SYNOPSIS...LKB NEAR TERM...LKB SHORT TERM...LKB LONG TERM...SAM AVIATION...ESS MARINE...SAM

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