Area Forecast Discussion
Issued by NWS Wakefield, VA

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KAKQ 192104 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 404 PM EST FRI DEC 19 2014 .SYNOPSIS... WEAK LOW PRESSURE WILL TRACK FROM THE GULF OF MEXICO EASTWARD AND OFF THE SOUTHEAST COAST LATE TONIGHT THROUGH SATURDAY NIGHT. HIGH PRESSURE WILL BE OVER THE AREA AGAIN DURING SUNDAY. ANOTHER LOW PRESSURE AREA MOVES NORTHEAST OUT OF THE GULF OF MEXICO AND UP ALONG THE COAST LATE SUNDAY NIGHT THROUGH MONDAY NIGHT. && .NEAR TERM /THROUGH SATURDAY/... LATEST SFC ANALYSIS DEPICTS ~995 MB LO PRES OVER THE CANADIAN MARITIMES WITH BROAD ~1028 MB HI PRES CENTERED OVER THE MIDWEST...RIDGING ESE INTO THE MID ATLC STATES. WEAK LOW PRESSURE IS ALSO DEVELOPING ACRS THE WRN GULF OF MEXICO...WITH PRECIP OVER LA/MS/AL AS OF 20Z THIS AFTN. STILL MAINLY CLEAR SKIES OVER THE AKQ FORECAST AREA...BUT SOME HIGH CIRRUS HAS STARTED TO OVERSPREAD THE REGION FROM THE SW (AND BKN/OVC STRATO-CU HAS BEEN SLOW TO ERODE OVER THE ERN SHORE. CURRENT TEMPS ARE GENLY IN THE 40S...AS CHILLY AS THE UPPER 30S AT KWAL/KOXB IN THE CLOUDS...AND AS WARM AS AROUND 50 OVER NE NC AND SOUTH CENTRAL VA. FOR TONIGHT...DRY WX WILL PERSIST EVEN AS HIGH CLOUDS GRADUALLY THICKEN/LOWER OVERNIGHT. EXPECT TEMPS TO RAPIDLY DROP AFTER SUNSET UNDER MAINLY CLEAR SKIES...THEN BECOME NEARLY STEADY OVERNIGHT AS CLOUDS SLOWLY INCREASE. LOWS MID 20S TO LOWER 30S. SAT...SYSTEM FROM THE GULF CONTINUES TO REMAIN SHUNTED OFF TO OUR SOUTH AS MID LEVEL FLOW REMAINS FAIRLY ZONAL. NAM/GFS STILL SHOW SOME FORCING ALOFT MAKING WAY INTO PIEDMONT BETWEEN 12-18Z/SAT AND BUFKIT SOUNDINGS SHOW SOME MODEST LIFT THROUGH THE DENDRITIC GROWTH LAYER. PTYPE ACRS THE PIEDMONT WOULD TEND TO BE SNOW/SLEET SAT AM ALTHOUGH SFC TEMPS SHOULD BE ABOVE 32 F (SFC WET BULBS IN THE UPPER 20S INITIALLY). LOW LEVELS REMAIN QUITE DRY HOWEVER...SO ANY PRECIP WILL BE VERY LIGHT (GENLY A FEW HUNDREDTHS IF THAT...WITH A TRACE MORE LIKELY). THUS...WILL ONLY GO WITH 30% POPS AT MOST. BY LATE MORNING/EARLY AFTN...AREA OF FORCING OVER THE PIEDMONT/CENTRAL VA WEAKENS AS THE SFC LOW PUSHES OFF THE SE COAST. WILL CARRY LOW CHC POPS IN FAR SE ZONES (ALL RAIN) THROUGH THE AFTN (ALTHOUGH MOST OF THE PRECIP SHOULD STAY S OF THE CWA). CLOUDY TO MSTLY CLOUDY W/ HIGHS GENLY 40-45 F SAT. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... SFC HIGH PRESSURE NOSES SOUTH INTO THE REGION SAT NIGHT/SUN...WITH DRY CONDS THEN FOR SAT NGT AND SUN. LOWS IN THE 20S N TO THE 30S SE SAT NIGHT...WITH HIGHS MAINLY FROM 45-50 F ON SUN. NEXT SYSTEM...THIS ONE MORE AMPLIFIED WILL AFFECT THE AREA ON MON...WITH LIKELY POPS ALL ZONES BY LATE MON AM/MON AFTN. LOOKS LIKE ALL RAIN ASIDE FROM A BRIEF MIX POSSIBLE AT ONSET IN FAR NW COUNTIES. HIGHS MON ONLY AROUND 40 F NW TO THE MID 50S FAR SE IN CAD SETUP. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... LOW PRESSURE LIFTS TO THE NE MONDAY NIGHT WITH POPS DIMINISHING FROM SW-NE OVERNIGHT. MID-LEVEL RIDGING BRIEFLY BUILDS INTO THE REGION TUESDAY. HOWEVER...MOIST SOUTHERLY FLOW ORIGINATING FROM THE GULF STREAM WILL PREVAIL SO LOW CHC (30%) POPS WILL BE MAINTAINED. A VERY DYNAMIC SYSTEM LIFTS NNE WEST OF THE APPALACHIANS TUESDAY NIGHT WITH THE ATTENDANT COLD FRONT CROSSING THE MID-ATLANTIC WEDNESDAY. THE FIRST POTENTIAL OF RAIN ARRIVES TUESDAY NIGHT ASSOCIATED WITH MOIST WAA. THE SECOND POTENTIAL WILL BE WEDNESDAY AHEAD OF THE COLD FRONT. THERE IS A POTENTIAL FOR THUNDER WEDNESDAY AS SURFACE DEWPOINTS POTENTIALLY EXCEED 60F (ESPECIALLY OVER THE COASTAL PLAIN). THE PATTERN DOES SUPPORT THE POSSIBILITY OF A DYNAMICALLY FORCED LINE OF CONVECTION CONTAINING STRONG WIND GUSTS AS CURRENT FORECAST GUIDANCE SUGGESTS A 925-700MB WIND FIELD AVERAGING 40-50KT. THIS WOULD BE A CLIMATOLOGICALLY RARITY THIS TIME OF YEAR...SO CONFIDENCE IS ON THE LOW-SIDE GIVEN THAT THIS IS 5-6 DAYS OUT. TEMPERATURES WILL BE VERY MILD AHEAD OF THE FRONT TUESDAY AND WEDNESDAY...WITH HIGHS AVERAGING FROM THE MID 50S NW...TO MID/UPPER 60S SE. DRY AND BREEZY CONDITIONS WILL LIKELY PREVAIL BY CHRISTMAS DAY...WITH HIGH TEMPERATURES OF 50-55. THE FLOW BECOMES MORE SW BY FRIDAY WITH CURRENT FORECAST HIGHS OF 55-60...BUT 60-65 IS POSSIBLE BASED ON LOW-LEVEL THICKNESS FIELDS. && .AVIATION /21Z FRIDAY THROUGH WEDNESDAY/... THERE IS A VERY DISTINCT BOUNDARY BTWN BKN-OVC STRATOCUMULUS (AROUND 3500 FT AGL) OVER NRN VA AND THE MD/VA LOWER EASTERN SHORE VERSUS THE REST OF THE REGION...WHERE AN AREA OF SUBSIDENCE PASSING FROM WEST TO EAST IS KEEPING SKIES CLEAR. IN ADDITION...NW WINDS ARE GUSTING TO 15-20 KT WITHIN AND JUST SOUTH OF THE STRATUS DECK. THE GUSTY WINDS WILL CALM DOWN BY SUNSET BUT THE STRATUS WILL REMAIN STEADFAST THROUGH TONIGHT INTO SATURDAY MORNING. WINDS AT KORF TURN MORE TO THE NORTH OVERNIGHT AND A STRATUS DECK AROUND 2000 FT AGL COULD DEVELOP OFF THE BAY. OTHERWISE...HIGH CLOUDS WILL INCREASE ACROSS THE REGION FROM THE SW AFTER 20/0700Z TONIGHT. LOW PRESSURE TRACKS WELL SOUTH OF THE AREA SAT/SAT NIGHT WITH CLOUDS THICKENING AND LOWERING AS SATURDAY PROGRESSES. STEADY PRECIPITATION WILL BE SHUNTED WELL SOUTH OF THE AREA...HOWEVER THERE IS A SLIGHT CHANCE FOR RAIN SHOWERS ALONG AND SOUTH OF THE VA/NC BORDER FROM LATE MORNING THROUGH THE AFTN. PRECIP COMES TO AN END SATURDAY EVENING AND CONDITIONS WILL GRADUALLY IMPROVE FROM WEST TO EAST THROUGH THE REST OF SAT NIGHT. HIGH PRESSURE BUILDS TO THE NORTH OF THE AREA SUNDAY. A SERIES OF LOW PRESSURE SYSTEMS AND COMPLEX FRONTAL BOUNDARIES WILL BRING CHANCES FOR RAIN AND PERIODS OF LOW CEILINGS AND VISIBILITIES BEGINNING MONDAY. && .MARINE... HIGH PRESSURE REMAINS NW OF THE REGION TONIGHT...WITH LINGERING LIGHT CAA ALONG THE COAST. THIS WILL MAINTAIN A 10-15KT NNW WIND OVERNIGHT...WITH 2-3FT SEAS IN THE OCEAN AND 1-2FT WAVES IN THE BAY. HIGH PRESSURE SPREADS ACROSS NEW ENGLAND SATURDAY AND SATURDAY NIGHT...WITH THE SURFACE RIDGE AXIS REMAINING INLAND OVER THE PIEDMONT. THIS WILL MAINTAIN LIGHT (5-10KT) NORTHERLY FLOW OVER THE MARINE AREA. HIGH PRESSURE MOVES FARTHER E SUNDAY AND SUNDAY NIGHT...AS LOW PRESSURE DEVELOPS OFF THE SOUTHEAST COAST SUNDAY NIGHT...AND THEN TRACKS NE OFF THE MID ATLANTIC COAST MONDAY AND MONDAY NIGHT. THE SURFACE PRESSURE GRADIENT TIGHTENS AHEAD OF THE LOW MONDAY...WHICH HAS THE POTENTIAL TO PRODUCE 15-20KT EASTERLY FLOW OVER THE OCEAN AND LOWER BAY. THIS ONSHORE FLOW COULD PRODUCE A PERIOD OF SCA CONDITIONS ESPECIALLY OVER THE SRN OCEAN ZONES (MAINLY FOR SEAS) AND LOWER BAY/MOUTH OF JAMES. THERE IS NO CAA IN THE WAKE OF THIS LOW...SO SUB-SCA CONDITIONS SHOULD PREVAIL LATER MONDAY NIGHT INTO TUESDAY. A STRONG LOW PRESSURE SYSTEM TRACKS W OF THE MOUNTAINS TUESDAY NIGHT...WITH A STRONG COLD FRONT CROSSING THE MID ATLANTIC COAST LATER WEDNESDAY. SCA CONDITIONS ARE LIKELY WEDNESDAY NIGHT INTO CHRISTMAS DAY AS HIGH PRESSURE BUILDS IN FROM THE WNW. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...LKB NEAR TERM...LKB SHORT TERM...LKB/MAS LONG TERM...AJZ/MAS AVIATION...BMD/MPR MARINE...AJZ

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.