Area Forecast Discussion
Issued by NWS Wakefield, VA

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
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
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KAKQ 241040 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 540 AM EST WED DEC 24 2014 .SYNOPSIS... A WARM FRONT WILL LIFT NORTHWARD THROUGH THE AREA THROUGH THIS MORNING AS A LOW PRESSURE SYSTEM STRENGTHENS WEST OF THE MOUNTAINS. AN ASSOCIATED COLD FRONT WILL CROSS THE AREA TONIGHT. HIGH PRESSURE BUILDS BACK IN FROM THE SOUTHWEST CHRISTMAS DAY THROUGH FRIDAY. && .NEAR TERM /THROUGH TONIGHT/... A DYNAMIC SYSTEM CONTINUES TO DEVELOP OVER THE CENTRAL GULF COAST STATES AND TENNESSEE VALLEY EARLY THIS MORNING. LOCALLY...A RESIDUAL COOL-WEDGE AIRMASS LINGERS WITH TEMPERATURES IN THE MID/UPPER 40S. A WARM FRONT/COASTAL FRONT LIES IMMEDIATELY OFFSHORE...AND WARMER TEMPERATURES ARE BEGINNING TO CREEP INTO COASTAL NE NC WITH ECG/ONX RISING INTO THE UPPER 50S AS OF 09Z. THE FIRST BATCH OF RA IS LIFTING NE ACROSS THE ERN THIRD OF THE AREA. OVERALL VSBYS HAVE IMPROVED AS RA MOVED ACROSS THE REGION...SO DENSE FOG IS NOT AN ISSUE AT THIS TIME. HOWEVER...DENSE FOG COULD DEVELOP OVER THE WATER OVER THE NEXT FEW HOURS AS A WARM/MOIST AIRMASS OFF THE GULF STREAM OVERSPREADS COOLER WATER. THE NEXT BATCH OF RA IS PRESENTLY TRACKING NE ACROSS WRN NC/CENTRAL SC AND THIS SHOULD OVERSPREAD THE REGION THROUGH THE MORNING. THE WARM FRONT SHOULD STEADILY LIFT SE-NW ACROSS THE COASTAL PLAIN AND INTO THE I-95 CORRIDOR THIS MORNING AS THE LOW DEEPENS TO THE W AND TRACKS NNE INTO THE OHIO VALLEY. A BLEND OF THE HI-RES ARW AND HRRR RESULTS IN TEMPERATURES RISING INTO THE MID 60S TO NEAR 70 BY MIDDAY ROUGHLY ALONG AND E OF AN AVC-RIC-CGE LINE...WITH THE WEDGE AIRMASS HOLDING STRONG OVER THE NW PIEDMONT. PERIODS OF RA SHOULD CONTINUE THROUGH THE AFTERNOON. AS TEMPERATURES AND DEWPOINTS RISE THERE IS A CHC OF THUNDER BY AFTERNOON WHEN COMBINED WITH A STRONG SYSTEM TO THE W. CLOUDS/RA SHOULD LIMIT DESTABILIZATION...SO SPC HAS ONLY THE SE PORTION OF THE AREA IN A MARGINAL SEVERE RISK DESPITE A WARM MOISTURE RICH AIRMASS AND A STRONG 925-700MB WIND FIELD. BY LATE AFTERNOON HIGHS SHOULD RANGE FROM THE MID/UPPER 60S FOR CENTRAL PORTIONS TO AROUND 70 SE...WITH MID/UPPER 50S OVER THE FAR NW PIEDMONT. HIGHS WILL BE NEAR RECORDS...SEE THE CLIMATE SECTION BELOW FOR DETAILS. THE COLD FRONT ARRIVES FROM THE W THIS EVENING AND MOVES W-E ACROSS THE AREA AFTER MIDNIGHT. HIGH POPS CONTINUE THROUGH THE EVENING...AND THEN RAPIDLY DIMINISH AFTER MIDNIGHT. A MENTION OF THUNDER WILL BE MAINTAINED FOR THE AREA THROUGH THE EVENING...AND THROUGH THE EARLY OVERNIGHT HOURS FOR COASTAL PORTIONS. && .SHORT TERM /THURSDAY THROUGH FRIDAY/... DRIER AIR ARRIVES CHRISTMAS MORNING AS HIGH PRESSURE BUILDS IN FROM THE W. A SLOWER FRONTAL PASSAGE WILL RESULT IN A MILD CHRISTMAS MORNING WITH LOWS RANGING FROM THE MID 40S FAR W...TO THE MID/UPPER 50S SE. THE SKY SHOULD BECOME MAINLY SUNNY WITH SCT AFTERNOON CU ALONG WITH BREEZY WESTERLY FLOW BY MID/LATE MORNING CHRISTMAS DAY. HIGHS SHOULD RANGE FROM THE MID 50S TO LOWER 60S CHRISTMAS DAY AS CAA IS WEAK AND WILL BE OFFSET BY DOWNSLOPE WARMING (AND DUE TO A WARM BEGINNING). CLEAR/SEASONABLE THURSDAY NIGHT WITH LOWS IN THE UPPER 20S TO MID 30S. SURFACE HIGH PRESSURE SETTLES IMMEDIATELY OFF THE COAST FRIDAY RESULTING IN LIMITED MIXING/LIGHT WINDS AND SUNNY CONDITIONS. HIGHS SHOULD GENERALLY BE IN THE 50S. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... THE MODELS ARE IN GOOD AGREEMENT TO BEGIN THE PERIOD FRIDAY NIGHT WITH THE STRONG RIDGING OVER THE SOUTHEASTERN US AND HIGH PRESSURE OVER THE SOUTHEAST...CENTERED OVER EASTERN VA/NC. BUT THE MODELS STRUGGLE WITH THE BREAKING DOWN OF THE RIDGE WITH THE GFS BREAKING IT DOWN MUCH MORE QUICKLY THAN THE ECMWF. THE GFS ALLOW THE NEXT COLD FRONT TO DROP INTO THE ARE SAT NIGHT AND MOVES IT SOUTH OF THE REGION BY SUNDAY MORNING...SETTING UP AN OVERRUNNING PATTERN SUNDAY AFTERNOON INTO MONDAY MORNING. THE ECMWF...AND THE 12Z IS FURTHER NORTH WITH FEATURES THAN 00Z RUN...KEEPS THE RIDGE MUCH STRONGER OVER THE SE AND DOES NOT ALLOW THE COLD FRONT TO MOVE THROUGH THE AREA SAT NIGHT. IT STALLS THE FRONT OVER THE AREA ON SUNDAY AND AS A WAVE OF LOW PRESSURE FORMS ALONG THE BOUNDARY AND LIFTS NE INTO THE CENTRAL APPALACHIANS...IT PUSHES GULF MOISTURE INTO THE AREA. THE 00Z ECMWF PUSHED THE WAVE OFF THE COAST BY MONDAY...BUT THE 12Z RUN LIFTS THE LOW TO THE NORTH AND DRAGS A COLD FRONT ACROSS THE REGION ON TUESDAY. SO FOR NOW WITH THE GREAT SPREAD IN THE MODELS...HAVE TRENDED TOWARD HPC/WPC GUIDANCE...WHICH IS SIMILAR TO THE 00Z ECMWF AND BROUGHT THE WAVE INTO THE REGION ON SUNDAY AFTERNOON AND EVENING WITH IT EXITING BY MONDAY AFTERNOON. HAVE INCREASED POPS TO 50% FOR THAT PERIOD...KEEPING SATURDAY DRY. HAVE ALSO GONE DRY ON MONDAY NIGHT INTO TUESDAY. THE BIG DIFFERENCE COMES TO TEMPERATURES AS THE GFS WOULD ALLOW MUCH COLD AIR INTO THE REGION BEGINNING ON SUNDAY THROUGH TUESDAY. THIS COULD ALSO POTENTIALLY LEAD TO SOME WINTRY PCPN WITH WAVE ON SUNDAY NIGHT. FOR NOW HAVE KEPT TEMPERATURES ABOVE FREEZING AND ALL RAIN WITH THE COLD AIR BEING KEPT MORE TO THE NORTH. FOR TEMPERATURES HAVE ALLOW FOR A GRADUAL COOL DOWN THROUGH THE PERIOD WITH THE COLDEST AIR ARRIVING ON TUESDAY WITH HIGHS IN THE 40S. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/... LIFR CIGS WERE MOST PROMINENT ACRS THE CWA HOWEVER SOME TEMPORARY IMPROVEMENT HAS DEVELOPED...ESPECIALLY IN THE VSBY AND MOST OFTEN IN SE PORTIONS. THE WARM FRONT IS STILL JUST E OF HATTERAS DESPITE SE WINDS AND INCREASING TEMPERATURES TOWARD COASTAL AREAS OF OUR CWA. WITH THAT IN MIND...ANY IMPROVEMENT IN CIGS ARE EXPECTED TO BE TEMPORARY. AN AREA OF RAIN...BRIEFLY HEAVY...WAS MOVING QUICKLY NE THROUGH THE AREA. EXPECT THAT ONCE THE HEAVIER PCPN MOVES OUT THAT CONDITIONS WILL BE MORE CONSISTENTLY IFR. THE WARM FRONT IS EXPECTED TO LIFT TO THE NW/N WEDNESDAY MORNING. DESPITE THE FACT THAT LAVMOS AND NAM MOS HAVE PERSISTENT IFR AT THE TAF SITES...GFS MOS AND NAM DMO (DIRECT MODEL OUTPUT MOS) HAVE SOME MODEST IMPROVEMENT BY EARLY AFTN AT ORF AND ECG AND POSSIBLY PHF. WITH WARM SECTORING EXPECTED ESPECIALLY AT THESE LOCATIONS...HAVE MVFR BY AROUND 18Z AT ORF AND ECG. HAVE TRIED TO APPLY IMPROVEMENT CONSERVATIVELY. MODELS TEND TO IMPROVE WIDESPREAD IFR CONDS TOO FAST BUT AT THE SAME TIME CAN BE TOO LOW IN WARM SECTOR SITUATIONS. THEREFORE...CONFIDENCE IN THIS PART OF THE FORECAST IS LOW. OUTLOOK...CURRENT FORECAST HAS WIDESPREAD PCPN WITH SLGT CHC FOR THUNDER WEDNESDAY NIGHT AND EARLY THURSDAY MORNING. THE COLD FRONT MOVES THROUGH THURSDAY MORNING SHIFTING WINDS TO WESTERLY. CONDITIONS SHOULD IMPROVE RATHER QUICKLY FOLLOWING THE FRONTAL PASSAGE. HIGH PRESSURE DOMINATES THROUGH SATURDAY WITH DRY WEATHER. A CHC FOR RAIN RETURNS SUNDAY AS LOW PRESSURE APPROACHES FROM THE WEST. && .MARINE... WILL CONTINUE TO MONITOR THE NEED FOR A DENSE FOG ADVISORY THIS MORNING OVER THE MARINE AREA AS WARM MOIST AIR MOVES IN OVER RELATIVELY COOL WATER. AS OF 08Z...WINDS REMAIN LIGHT OVER THE MARINE AREA BUT ARE FORECAST TO INCREASE FROM THE SE AND THEN S THIS MORNING AS A WARM FRONT MOVES N THROUGH THE WATERS AND LOW PRESSURE DEEPENS OVER THE OHIO VALLEY. SCA IS IN EFFECT FOR ALL THE WATERS EXCEPT THE RIVERS SAVE THE LOWER JAMES. SCA CONDITIONS OVER INLAND WATERS MAY BE MINIMAL AT FIRST DUE TO LIMITED MIXING BUT WILL BECOME MORE FAVORABLE THURSDAY MORNING. HAVE ADDED THE LOWER JAMES WITH TIMES STAGGERED SLIGHTLY FROM THE BAY (STARTING AT 21Z TODAY AND ENDING 3 HOURS EARLIER THURSDAY). LATER SHIFTS MAY NEED TO CONSIDER SCA BEHIND THE COLD FRONT FOR OTHER RIVER ZONES ON THURSDAY MORNING. SCA IS ALREADY IN EFFECT N OF PARRAMORE ISLAND. SEAS ARE EXPECTED TO BUILD TO 5 FT OR HIGHER BY 18Z S OF THERE AND DECIDED TO BEGIN SCA S OF PARRAMORE ISLAND AT 15Z TO ALLOW SUFFICIENT CUSHION. HIGH PRESSURE THEN BUILDS INTO THE REGION ON THURSDAY NIGHT AND LINGERS THROUGH SATURDAY AS A STRONG UPPER LEVEL RIDGE BUILDS INTO THE SOUTHEASTERN US AND KEEPS STRONG HIGH PRESSURE AT THE SURFACE OVER THE REGION THROUGH SATURDAY. LOW PRESSURE APPROACHES FROM THE SW SUNDAY AND MOVES ACROSS THE REGION MONDAY. PRELIMINARY INDICATIONS DO NOT INDICATE THAT A SCA WILL BE NEEDED WITH THIS SYSTEM. && .TIDES/COASTAL FLOODING... WATER LEVELS AT BISHOPS HEAD AND CAMBRIDGE ARE EXPECTED TO APPROACH MINOR FLOODING LATE TODAY AND EARLY THIS EVENING. && .CLIMATE... RECORD HIGHS FOR CHRISTMAS EVE/WED 12/24: RICHMOND.......71 F (1988) NORFOLK........75 F (1891) SALISBURY......67 F (1990) ELIZ CITY NC...75 F (1990) && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 4 PM EST THURSDAY FOR ANZ630>634. SMALL CRAFT ADVISORY FROM 1 PM THIS AFTERNOON TO 1 PM EST THURSDAY FOR ANZ638. SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 4 PM EST THURSDAY FOR ANZ654-656-658. SMALL CRAFT ADVISORY UNTIL 4 PM EST THURSDAY FOR ANZ650-652. && $$ SYNOPSIS...AJZ/ALB NEAR TERM...AJZ SHORT TERM...AJZ/LKB LONG TERM...ESS AVIATION...LSA MARINE...LSA TIDES/COASTAL FLOODING... CLIMATE...

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