Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 240153 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 853 PM EST TUE DEC 23 2014 .SYNOPSIS... A WARM FRONT WILL LIFT NORTHWARD THROUGH THE AREA OVERNIGHT THROUGH WEDNESDAY MORNING AS A LOW PRESSURE SYSTEM STRENGTHENS WEST OF THE MOUNTAINS. AN ASSOCIATED COLD FRONT WILL CROSS THE AREA WEDNESDAY NIGHT. HIGH PRESSURE BUILDS BACK IN FROM THE SOUTHWEST CHRISTMAS DAY THROUGH FRIDAY. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... FG...PSBLY BECOMING DENSE...WILL RMN PROBLEMATIC OVR MOST THE AREA THROUGH OVRNGT HRS AS SFC WARM FRONT/(MUCH) WARMER AIR BEGINS TO PUSH N INTO THE RGN. ALSO...AREA OF RA NOW SPREADING INTO SOUTH CENTRAL PORTIONS OF VA/INTERIOR NE NC ATTM...ALSO ADDED ISOLD T THOSE AREAS. PREV DISCUSSION... LATEST SFC ANALYSIS SHOWS WEAK LOW PRESSURE JUST OFF THE NJ COAST...SLOWLY LIFTING NE. SATURATED LOW LEVELS REMAIN BUT VSBYS HAVE IMPROVED TO AT OR ABOVE 2SM IN MOST AREAS AS FOG HAS LIFTED AND NOW JUST SEEING MAINLY LOW STRATUS. FOG NOW MOST PREVALENT OVER THE WATER BUT VSBYS HAVE IMPROVED HERE AS WELL. EXPECT FOG TO BECOME AN ISSUE AGAIN LATER THIS EVENING OR TONIGHT AS HIGHER DEW PTS SURGE NORTHWARD TO THE N OF THE APPROACHING WARM FRONT. SFC WARM FRONT WILL LIFT NORTH ACRS THE REGION LATER TONIGHT AND WILL ALLOW FOR THE AREA TO BE WARM SECTORED ON WED. DEEP MOISTURE TRANSPORT OCCURS TONIGHT...RAISED POPS TO NEAR 100% ALL AREAS...AS MODERATE TO HEAVY RAIN MOVES THROUGH THE REGION...REACHING SRN AREAS 00-03Z...NRN AREAS AFTER MIDNIGHT. LOWS TONIGHT IN THE 40S MOST AREAS...WITH TEMPERATURES LIKELY TO RISE AFTER MIDNIGHT (ESP IN SE ZONES). && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/... LATEST RUNS OF THE NAM/GFS/ECMWF AND VARIOUS HIGH RES MODELS REMAIN IN GOOD AGREEMENT OVERALL W/ THE PATTERN WED/WED NIGHT. A ~995MB SFC LOW OVER THE TN/OH VALLEY WILL TRACK RAPIDLY NNE FROM AND INTENSIFY THROUGH THE DAY...REACHING THE CENTRAL GREAT LAKES BY 00Z/THU. OVER AKQ AREA...DEEP SOUTHERLY FLOW WILL INCREASE...AND SHOULD SCOUR OUT ANY RESIDUAL WEAK LOW LEVEL WEDGING OVER THE PIEDMONT (WILL MAINTAIN SOME MENTION OF FOG IN THE AM HRS ACRS THE NW ZONES AS WELL AS THE NRN WATERS). DEW PTS SOAR INTO THE UPPER 50S TO LOWER-MID 60S BY LATE MORNING/AFTN. AT THIS POINT THERE DOES NOT LOOK TO BE MUCH IN THE WAY OF CLEARING POTENTIAL (HIGH SHEAR BUT VERY MINIMAL CAPE) ON WED TO LEAD TO SEVERE WX. SPC HAS MUCH OF THE CWA IN A MARGINAL RISK FOR SEVERE WX...PRIMARILY DUE TO STRONG FLOW IN THE H9 TO H5 WINDS (HIGH SHEAR). CAPES WILL BE MINIMAL AND TIMING OF FRONT WILL BE WED EVENING/WED NIGHT...NOT OPTIMAL FOR A SEVERE WX OUTBREAK. WILL CONTINUE TO MENTION MARGINAL THREAT IN HWO...AND ISO TSTMS WED EVENING/ERLY THU MORNING AND IT WIL NOT NOT TAKE A LOT TO MIX DOWN ~40+ MPH WINDS AS THE FRONT PUSHES THROUGH. HIGHS WED INTO THE M-U60S TO LOWER 70S (CLOSE TO RECORD HIGHS/SEE CLIMATE SECTION). CATEGORICAL POPS ALL AREAS WED (ALTHOUGH PRECIP MAY SCATTER OUT FOR A TIME IN THE WARM SECTOR. HIGHEST POPS SHIFTING OFF THE COAST LATER WED NIGHT AS THE COLD FRONT PUSHES THROUGH AND DRIER AIR MOVES IN FROM THE WEST BY CHRISTMAS MORNING. SLOWER PASSAGE OF THE FRONT WILL MAKE FOR VERY MILD MINS CHRISTMAS MORNING WITH LOWS IN THE MID 40S FAR WEST...TO THE MID 50S SE. SKIES BECOME MOSTLY SUNNY WITH BREEZY WESTERLY FLOW BY MID/LATE MORNING CHRISTMAS DAY. RAISED HIGHS TO 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 THU NIGHT W/ LOWS IN THE UPPER 20S TO MID 30S. SFC HIGH IN CONTROL/LIGHT WINDS AND MAINLY CLEAR FRI. HIGHS 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 /02Z WEDNESDAY THROUGH SUNDAY/...
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MOSTLY IFR/MVFR CONDS ACROSS THE ENTIRE CWA AS AREA IS COVERED IN LOW CLOUDS AND VSBY DUE TO LOW PRES SYS AND COASTAL FRONT...AND DEEP E-S FLOW FROM THE GULF AND ATL OCEAN. AREA OF RAIN IS ALSO MOVG NORTH FROM THE CAROLINAS AND WILL AFFECT THE WX THRU THE FORECAST PERIOD. IN ADDITION...A LOW PRES SYS WILL LIFT THRU THE OH VALLEY AND PUSH A WARM FRONT THRU THE REGION DURING THE OVERNIGHT AND MORNING HOURS. CIGS/VSBY EXPECTED TO BE REDUCED TO LIKELY IFR/LIFR CONDS FOR MOST OF THE NIGHT. RAIN AND PSBL ISOLATED TSTMS WILL MOVE INTO S CENTRL VA EARLY TONIGHT AND AND CENTRL VA BEFORE MIDNIGHT. THERE MAY BE A TEMPO IMPROVEMENT WITH CIGS AS SHOWERS/CONVECTION MOVE THRU BUT DO NOT EXPECT IT TO BE LONG. WARM FRONT WILL BREAK THRU WED MORNING AND CIGS SHOULD SLOWLY IMPROVE TO MVFR CONDS BY AFTN. CONFIDENCE IN CIGS IMPROVING TO BETTER THAN 1000 FT BY WED AFTN IS LOW AND WILL BE DEPENDENT ON RAIN AND WHETHER THE WARM FRONT MOVES THRU AS EXPECTED. THERE IS ALSO A SLIGHT CHC OF THUNDER WEDNESDAY AFTERNOON AND EVENING. A GUSTY SOUTHERLY WIND IS LIKELY WEDNESDAY AFTERNOON AND EVENING AHEAD OF A COLD FRONT...WHICH SWEEPS THROUGH THE REGION EARLY THU MORNING. DRIER CONDITIONS SHOULD PREVAIL BY CHRISTMAS DAY ALONG WITH A GUSTY WESTERLY WIND.
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&& .MARINE... THE WEAK LOW PRESSURE AREA JUST OFF THE COAST CONTINUES TO KEEP THE SEAS UP AROUND SCA LEVELS IN THE NORTHERN MARINE ZONES TONIGHT WITH SEAS OF 5 TO 6 FT. SEAS HAVE BEEN SLOWLY DROPPING THERE AND THEY SHOULD FALL BELOW 5 FT THIS EVENING. SO HAVE EXTENDED THE SCA THERE THROUGH 10 PM FOR THE SEAS. MEANWHILE...LOW PRESSURE ALONG THE NORTHERN GULF COAST HAS BEGUN TO DEVELOP ALONG A STRONG COLD FRONT. THIS LOW WILL DEEPEN AND LIFT NORTHWARD INTO THE OHIO VALLEY TONIGHT INTO WEDNESDAY. AHEAD OF THE FRONT...A WARM FRONT WILL LIFT ACROSS THE WATERS. AHEAD OF THE FRONT...EXPECT MORE LIGHT RAIN AND DRIZZLE TO DEVELOP OVERNIGHT ALONG WITH REDUCED VISIBILITIES. A DENSE FOG ADVISORY MAY BE NEEDED LATER TONIGHT BEFORE THE WARM FRONT PASSES THE REGION. AS THE WARM FRONT CROSSES...THE WINDS WILL SHIFT FROM AN E-SE DIRECTION TO A SW DIRECTION. AS THE LOW DEEPENS...THE PRESSURE GRADIENT WILL TIGHTEN AND THE WINDS INCREASE TO 15 TO 20 ON THE BAY AND 20 TO 25 KT IN THE COASTAL ZONE. THE FRONT WILL CROSS THE AREA OVERNIGHT WED NIGHT AND SHIFT THE WINDS TO THE WEST. BUT THE COLD ADVECTION BEHIND THE FRONT IS NOT STRONG SO EXPECT THAT THE WINDS WILL DIMINISH ON CHRISTMAS DAY DURING THE AFTERNOON HOURS AS HIGH PRESSURE BUILDS INTO THE AREA. SO HAVE RAISED SCA FLAGS FOR WED AFTERNOON THROUGH THURSDAY AFTERNOON FOR THIS SYSTEM. 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. THE MODELS BEGIN TO STRUGGLE WITH THE NEXT SYSTEM FOR SUNDAY AS A FRONT TRIES TO MOVE INTO THE WATERS. FOR NOW EXPECT THE FRONT TO APPROACH FROM THE NORTH AND THEN STALL A LOW PRESSURE LIFTS NORTHEASTWARD INTO THE REGION WITH SHOWER AND LIGHT RAIN. THIS COULD AGAIN LIMIT VISIBILITIES...BUT WINDS ARE NOT EXPECTED TO BE STRONG ENOUGH TO REACH SCA LEVELS. && .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) && .EQUIPMENT... THE NOAA ALL HAZARDS RADIO SYSTEM AT WAKEFIELD VA HAS RETURNED TO SERVICE. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 1 PM WEDNESDAY TO 4 PM EST THURSDAY FOR ANZ630>634-650-652-654-656-658. SMALL CRAFT ADVISORY UNTIL 10 PM EST THIS EVENING FOR ANZ650- 652. && $$ SYNOPSIS...ALB/LKB NEAR TERM...ALB/LKB SHORT TERM...JDM/LKB LONG TERM...ESS AVIATION...DAP/JEF MARINE...ESS CLIMATE... EQUIPMENT...

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