Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 291011 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 511 AM EST MON DEC 29 2014 .SYNOPSIS... COLD FRONT HAS CLEARED THE LOCAL AREA THIS MORNING. LOW PRESSURE WILL TRACK NORTHEAST ALONG THE FRONT TODAY...LOCATING OFF THE MID ATLANTIC COAST TONIGHT. HIGH PRESSURE SLOWLY BUILDS INTO THE REGION FROM THE WEST TUESDAY THROUGH MIDWEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... LATEST WATER VAPOR IMAGERY DEPICTS THE NEXT IN A SERIES OF SHEARING SHORTWAVES LIFTING INTO THE TN VALLEY THIS MORNING. FAVORABLE PLACEMENT IN THE RRQ OF DEPARTING 150+ KT JET IN TANDEM WITH MODEST HEIGHT FALLS AND ANOMALOUS MOISTURE (PWATS 200% OF NORMAL) HAS RESULTED IN WIDESPREAD ANAFRONTAL RAINFALL. SFC FRONT/WIND SHIFT HAS NEARLY CLEARED THE LOCAL AREA EARLY THIS MORNING...BUT MID LEVEL FRONT AND COLD/DRY AIR MASS LAGS BEHIND. WAVE OF LOW PRESSURE LIFTS INTO THE CAROLINAS THIS MORNING...AS THERMAL ADVECTION INCREASES OVER THE LOCAL AREA. SFC FLOW ALSO BECOMES ONSHORE...RESULTING IN ABUNDANT LOW LEVEL MOISTURE. THE RESULT WILL BE AN EXPANSION OF PRECIP OVER THE LOCAL AREA...SPREADING EWD THRU THE MORNING HOURS. WAVE SHEARS FURTHER...PUSHING OFFSHORE THIS AFTERNOON. PRECIP WILL BEGIN TO RAMP DOWN OVER THE NW ZONES FIRST...SPREADING SEWD THRU THE AFTERNOON AS DRY AIR ALOFT PENETRATES THE REGION IN INCREASING WLY FLOW ALOFT. LIGHT RAINFALL EXPECTED TO PERSIST OVER THE SE THIS AFTERNOON. HOWEVER...ONSHORE FLOW PERSISTS AS STRONG WINDS ALOFT PROVIDE UVM. THE RESULT WILL BE SCT LIGHT RAIN/DRIZZLE OVER THE AREA THIS AFTERNOON INTO THIS EVENING. TOTAL QPF AMOUNTS WILL RANGE FROM ONE QUARTER TO ONE HALF INCH. CAA BEHIND THE FRONT WILL RESULT IN DROPPING TEMPS THRU THE DAY. TEMPS PROGGED TO FALL INTO THE LOW 40S NW TO MID 50S SE EARLY THIS MORNING (THE HIGH FOR TODAY)...FALLING INTO THE LOW-MID 40S THIS AFTERNOON. CLOUDS WILL PERSIST THRU THE DAY. DEWPOINTS WILL FALL INTO THE MID 30S TO LOW 40S WITH NE WINDS 10-15 MPH. THE RESULT WILL BE A COLD/RAW DAY. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... THE NEXT SHORTWAVE EJECTS FROM THE DESERT SW EWD INTO THE MIDWEST TONIGHT. STRONG WINDS PERSIST ALOFT AS THE H85 TROUGH REMAINS WEST OF THE LOCAL AREA. DRY WLY FLOW ALOFT CONTINUES TO DRY OUT THE MID-UPPER LEVELS...BUT SOUNDINGS INDICATE LOW LEVEL MOISTURE WILL PERSIST THANKS TO NELY FLOW. MODEST UPSLOPE FLOW WILL PRODUCE SHOWERS OVER THE CNTRL APPALACHIANS OVERNIGHT. DIFFERENCES PERSIST IN MODELS OVERNIGHT IN RESPECT TO THERMAL PROFILES AND LIFT. NAM/SREF REMAINS ON THE STRONGER SIDE WITH THE GFS/ECMWF ON THE WEAKER/FLATTER SIDE. PREFER THE ONGOING TREND TOWARD THE GFS/ECMWF AS FLOW REMAINS PROGRESSIVE AND ENERGY ENCOUNTERS CONFLUENT FLOW. AS A RESULT...HAVE MAINTAINED CHANCE POPS OVER THE PIEDMONT AS PRECIP MAY SPREAD EWD FROM THE HIGHER TERRAIN THANKS TO MOIST LOW LEVELS. HOWEVER...LITTLE MOISTURE AND FORCING IN THE SNOW GROWTH LAYER (-12 TO -18C) WILL RESULT IN ONLY LIGHT PRECIP. LIGHT RAIN/DRIZZLE PERSIST OVER CNTRL VA. CAA WANES BRIEFLY TONIGHT AS DEWPOINTS LEVEL OFF IN THE LOW-MID 30S. HOWEVER...WITH THE PASSAGE OF THE MID-LEVEL FRONT...EXPECT H85 TEMPS TO DROP BELOW 0C LATE TONIGHT. HAVE TRENDED LOW TEMPS TONIGHT UPWARDS SLIGHTLY...GENERALLY IN THE LOW-MID 30S. AS WET BULB TEMPS DROP TO AROUND 32 OVER THE NW PIEDMONT AND NRN VA...THERE WILL BE A PERIOD FOR A RAIN/SNOW MIX. NO ACCUMULATION IS EXPECTED. FRONT WILL ALSO REMAIN STALLED OFF THE SE COAST TONIGHT...RESULTING IN CHANCE POPS NEAR THE COAST. HAVE MAINTAINED CHANCE POPS OVER THE MD ERN SHORE AND NRN NECK THRU MID MORNING TUES AS A BAND OF FRONTOGENESIS/THERMAL ADVECTION MAY PRODUCE SOME WRAP AROUND MOISTURE. EXPECT A RAIN/SNOW MIX AS THERMAL PROFILES DROP TO NEAR OR BELOW 0C. NO ACCUMULATION IS EXPECTED ATTM. UPPER WAVE LIFTS OVER THE MID-ATLANTIC REGION TUES AS THE H85 TROUGH PUSHES OFFSHORE. THIS WILL RESULT IN A DRYING TREND THRU THE AFTERNOON. WILL BEGIN TO SEE THE SUN TUES AFTERNOON. NLY WINDS INCREASE AS A DRY/COLD AIR MASS SETTLES INTO THE REGION. FEW GUSTS UP TO 25 MPH EXPECTED NEAR THE COAST. TEMPS WARM INTO THE LOW-MID 40S TUES AFTERNOON. HIGH PRESSURE BEGINS TO BUILD INTO THE REGION FROM THE WEST TUES NIGHT-WEDS. CLEARING SKIES AND DEWPOINTS DROPPING INTO THE TEENS TO LOW 20S WILL RESULT IN LOW IN THE MID-UPPER 20S TUES NIGHT. DRY WEDS UNDER MOSTLY SUNNY-PARTLY CLOUDY SKIES. HIGHS IN THE MID 40S. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... 28/12Z GFS/ECMWF DEMONSTRATE GOOD AGREEMENT THROUGH FRIDAY. DRY AND MOSTLY CLEAR/SUNNY CONDITIONS SHOULD PREVAIL THROUGH THURSDAY NIGHT WITH INCREASING CLOUDS FROM THE SW FRIDAY AS LOW PRESSURE TRACKS ACROSS THE LOWER MISSISSIPPI VALLEY. HIGHS THURSDAY AND FRIDAY SHOULD RANGE FROM THE LOW/MID 40S NW...TO UPPER 40S/LOW 50S SE. LOWS THURSDAY MORNING SHOULD BE IN THE LOW/MID 20S...WITH MID/UPPER 20S FRIDAY MORNING. MODEL SOLUTIONS BEGIN TO DIVERGE FRIDAY NIGHT INTO SATURDAY AS THE ECMWF MAINTAINS A STRONGER HIGH ACROSS THE GREAT LAKES...WHICH KEEPS A WARM FRONT FARTHER S...WHILE THE GFS ALLOWS THE FRONT TO LIFT N THROUGH THE REGION. THE MAIN IMPACT AT THIS TIME APPEARS TO BE TEMPERATURE...AS OVERALL SURFACE TEMPERATURES APPEAR WARM ENOUGH TO SUPPORT MOSTLY RAIN (ASIDE FROM A CHC OF SLEET ACROSS THE N FRIDAY NIGHT). DIFFERENCES CONTINUE THROUGH THE WEEKEND WITH RESPECT TO THE FRONTAL BOUNDARY. THE ECMWF KEEPS THE BOUNDARY IN VICINITY OF THE LOCAL AREA THROUGH SUNDAY...WHILE THE GFS BRINGS THE COLD FRONT IN FROM THE NW BY SATURDAY NIGHT. OVERALL THE FORECAST DETAILS ARE LOW CONFIDENCE. HOWEVER...THE WEATHER DOES APPEAR TO BE UNSETTLED NEXT WEEKEND. && .AVIATION /10Z MONDAY THROUGH FRIDAY/...
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STEADY RAIN IS FINALLY BEGINNING TO OVERSPREAD THE AREA NW OF A LINE FROM KSBY TO KEMV. ANAFRONTAL PRECIPITATION WILL CONTINUE TO PUSH EWD THIS MORNING AS THE SFC COLD FRONT STALLS OFF THE CAROLINA COAST. MAIN IMPACTS ACROSS THE AREA WILL BE FROM POCKETS OF CIGS BELOW 1000FT AGL...IN ADDITION TO REDUCED VISIBILITIES DUE TO FOG/MIST ACROSS NE NC. VISIBILITIES WILL IMPROVE IN NE NC ONCE RAIN MOVES IN AND SCOURS OUT THE FOG/MIST. A BRIEF SURGE IN N-NE WINDS OFF CHES BAY (ESPECIALLY THE SRN BAY) WILL RESULT IN GUSTS OF 20-30KT THROUGH AT LEAST 29/1200Z BEFORE SUBSIDING TO AROUND 10KT. RAIN STARTS TO TAPER OFF FROM NW TO SE THIS AFTN/EVENING... HOWEVER THERE IS ENOUGH MOISTURE AND LIFT PRESENT TO KEEP A CHANCE FOR SHOWERS OVER THE PIEDMONT OVERNIGHT. SHOWERS WILL ALSO PERSIST ALONG THE COAST DUE TO PERSISTENT NE WINDS 15-25KT AND LOW STRATUS/CIGS MOVING IN FROM THE OCEAN. BY TUE AFTN...CONDITIONS DRY OUT IN THE PIEDMONT AND SHOWERS AT THE COAST TAPER OFF FROM NORTH TO SOUTH AS A MUCH COLDER AIRMASS TO THE NORTH PUSHES THE STALLED FRONT FARTHER ESE. EXPECT GRADUAL CLEARING FROM NW TO SE DURING TUE. HIGH PRESSURE AND VFR CONDITIONS PREVAIL THE REST OF THE WEEK.
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&& .MARINE...
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A SFC COLD FRONT HAS CROSSED THE WATERS AND IS EXPECTED TO STALL OFF THE CAROLINA COAST TODAY AND TONIGHT BEFORE BEGIN PUSHED FARTHER TO THE SOUTHEAST (AND OFFSHORE) ON TUESDAY. A NLY SURGE OF 15-25KT IS OCCURRING EARLY THIS MORNING...PRIMARILY ACROSS THE SRN BAY AND THE MOUTH OF THE JAMES RIVER...WHERE SCA FLAGS ARE IN EFFECT. ADDITIONALLY...ENOUGH OF A NNE WIND IS EXPECTED TO KEEP WINDS ELEVATED TO 15-20KT OVER CURRITUCK SOUND AND TO BUILD SEAS TO 4-5FT SOUTH OF CAPE CHARLES LATER THIS MORNING. SCA FLAGS FOR THESE AREAS WILL GO INTO EFFECT AT 7 AM. ANOTHER WAVE OF LOW PRESSURE TRACKS NE ALONG THE STALLED FRONT...BRINGING RAIN TO THE AREA TODAY THROUGH TUE MORNING BEFORE TAPERING OFF. WINDS WILL REMAIN NNE WITH SPEEDS INCREASING TO 15-25KT THIS EVENING THROUGH TUE BEFORE DIMINISHING TUE EVENING. SEAS ARE EXPECTED TO BUILD TO 5-7FT LATE TONIGHT INTO TUESDAY FOR THE SRN OCEAN ZONES AND 4-5FT NRN OCEAN ZONES...WITH 3-4FT WAVES IN THE BAY. SCA FLAGS HAVE BEEN EXTENDED THROUGH TUE NIGHT FOR SEAS LINGERING AROUND 5 FT AND ADDED FOR NRN OCEAN ZONES. ADDITIONAL SCA FLAGS WILL LIKELY BE HOISTED FOR CHES BAY AND THE MOUTH OF THE JAMES FOR LATE TONIGHT THROUGH TUE ONCE CURRENT FLAGS EXPIRE THIS MORNING/EARLY AFTN. HIGH PRESSURE GRADUALLY BUILDS INTO THE REGION THROUGH MID WEEK...WITH WINDS DIMINISHING AND SEAS/WAVES SUBSIDING.
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&& .EQUIPMENT... KDOX 88D RADAR IS EXPECTED TO BE OUT OF SERVICE THROUGH AT LEAST WED 12/31. SEE FTMDOX (FREE TEXT MESSAGE) FOR DETAILS. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 1 PM EST THIS AFTERNOON FOR ANZ631- 632-634. SMALL CRAFT ADVISORY UNTIL MIDNIGHT EST TUESDAY NIGHT FOR ANZ633. SMALL CRAFT ADVISORY UNTIL 10 AM EST THIS MORNING FOR ANZ630. SMALL CRAFT ADVISORY UNTIL 7 AM EST THIS MORNING FOR ANZ638. SMALL CRAFT ADVISORY FROM 10 PM THIS EVENING TO MIDNIGHT EST TUESDAY NIGHT FOR ANZ654. SMALL CRAFT ADVISORY FROM 10 AM THIS MORNING TO 7 AM EST WEDNESDAY FOR ANZ656-658. SMALL CRAFT ADVISORY FROM 3 AM TO 4 PM EST TUESDAY FOR ANZ650- 652. && $$ SYNOPSIS...MPR NEAR TERM...SAM SHORT TERM...SAM LONG TERM...AJZ AVIATION...BMD MARINE...BMD/AJZ EQUIPMENT...AKQ

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