Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 280923 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 423 AM EST SUN DEC 28 2014 .SYNOPSIS...
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COLD FRONT APPROACHES FROM THE WEST TODAY. LOW PRESSURE OVER THE GULF STATES WILL LIFT ALONG THE FRONT TODAY...REACHING THE LOCAL AREA THIS AFTERNOON. THE FRONT STALLS OFFSHORE TONIGHT AS ANOTHER AREA OF LOW PRESSURE LIFTS INTO THE CAROLINAS TONIGHT INTO MONDAY MORNING. THE FRONT REMAINS JUST OFFSHORE TUESDAY AS HIGH PRESSURE SLOWLY BUILDS IN FROM THE WEST.
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&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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PER LATEST WATER VAPOR IMAGERY...RIDGE AXIS HAS PUSHED OFFSHORE WITH MOISTURE STREAMING NEWD FROM THE SRN PLAINS AND WRN GULF OF MEX IN DEEP SWLY FLOW. LATEST BLENDED PRECIP WATER DEPICTS BROAD AREA OF 200 PCT OF NORMAL PRECIP WATER STREAMING ALONG THE APPALACHIANS INTO SE CANADA. UPSTREAM TROUGH AND ASSOCIATED COLD FRONT OVER THE CNTRL CONUS WILL CONTINUE TO PROGRESS EWD THIS MORNING AS AN AREA OF LOW PRESSURE STRENGTHENS OVER THE LOWER MS VALLEY. ASSOCIATED AREA OF PRECIP HAS SPREAD INTO THE TN VALLEY THIS MORNING...WITH CONVECTION OBSERVED OVER THE GULF STATES. SUBSIDENCE STILL WINNING OUT OVER THE LOCAL AREA WITH DEWPOINT DEPRESSIONS OF 10-15 DEGS. FIRST IN A SERIES OF UPPER WAVES FROM THE DEAMPLIFYING TROUGH OVER THE CNTRL CONUS LIFTS INTO THE REGION THIS MORNING. STRONG JET STREAK (180+ KT) DEVELOPS OVER THE GREAT LAKES/OH VALLEY...WHICH IN TANDEM WITH SHORTWAVE ENERGY WILL RESULT IN UVM OVER THE LOCAL AREA THIS MORNING. LOW LEVELS REMAIN DRY THRU EARLY MORNING...BUT UVM AND INCREASING MOISTURE WILL RESULT IN THE LOW LEVELS SATURATING QUICKLY. AS THE LOW LIFTS NEWD ALONG THE SFC FRONT...ISENTROPIC LIFT INCREASES. WITH ALL THAT SAID...THE RESULT WILL BE WIDESPREAD LIGHT RAIN SPREADING INTO THE REGION THIS MORNING AND THIS AFTERNOON. THE EXCEPTION WILL BE IN THE SE WHERE PRECIP WILL BE MORE SCATTERED IN NATURE. SFC LOW LIFTS ALONG THE FRONT INTO THE REGION THIS AFTERNOON AS THE FIRST WAVE OF PRECIP EXITS THE COAST. WILL HOLD ONTO CATEGORICAL POPS ACROSS THE NE LATE TODAY...BUT THE REST OF THE AREA WILL LIKELY SEE A LULL. HOWEVER...ABUNDANT LOW LEVEL MOISTURE AND THE UPPER JET WILL RESULT IN ADDITIONAL DRIZZLE/LIGHT RAIN. RAINFALL TOTALS TODAY WILL BE RATHER LIGHT...GENERALLY LESS THAN ONE QUARTER OF AN INCH. PRECIP AND ABUNDANT CLOUD COVER WILL PREVENT TEMPS FROM REACHING THEIR FULL POTENTIAL...WARMING INTO THE MID-UPPER 50S (8 TO 12 DEGS OVER MILD MORNING LOWS). WHERE PRECIP IS DELAYED IN THE SE...TEMPS EXPECTED TO WARM INTO THE LOW 60S.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/...
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COLD FRONT CROSSES THE REGION THIS EVENING...BUT STALLS OFF THE COAST IN DEEP LAYER SWLY FLOW. SRN PORTION OF THE FRONT STALLS OVER THE SE COASTAL PLAIN. MOISTURE REMAINS IN PLACE AS THE NEXT SHORTWAVE DEAMPLIFIES AND LIFTS INTO THE REGION. HEIGHT FALLS WILL PRODUCE ANOTHER WAVE OF LOW PRESSURE ALONG THE FRONT OVER THE SE...LIFTING ALONG THE FRONT INTO THE CAROLINAS MON MORNING. INCREASING ISENTROPIC LIFT IN TANDEM WITH THE RIGHT ENTRANCE REGION OF THE STRONG UPPER JET AND SHORTWAVE ENERGY WILL AGAIN RESULT IN WIDESPREAD PRECIP. HAVE BUMPED POPS UP TO CATEGORICAL AFTER MIDNIGHT TONIGHT INTO MONDAY MORNING ACROSS MUCH OF THE LOCAL AREA AS MODELS HAVE COME INTO GOOD AGREEMENT. FRONT FINALLY PUSHES OFFSHORE MON MORNING WITH CATEGORICAL POPS CONFINED TO THE SE MON MORNING. BUFR SOUNDINGS INDICATE LOW LEVELS WILL REMAIN SATURATED THRU THE DAY MON AS SWLY FLOW ALOFT PREVAILS. WEAK PERTURBATIONS IN THE FLOW ALOFT WILL RESULT IN ADDITIONAL CHANCES FOR LIGHT RAIN/DRIZZLE MON AFTERNOON. ABUNDANT CLOUD COVER PERSISTS. TOTAL QPF THRU MONDAY WILL RANGE FROM NEARLY ONE INCH IN THE WEST TO HALF AN INCH IN THE EAST. TEMPS DROP OFF THIS EVENING INTO THE MID-UPPER 40S NE TO LOW 50S SE...BEFORE LEVELING OFF THRU THE OVERNIGHT. BEST CAA ARRIVES LATE TONIGHT WITH LOWS EXPECTED IN THE LOW-MID 40S. CAA CONTINUES THRU THE DAY MON WITH TEMPS ONLY WARMING A FEW DEGS MON. HIGHS GENERALLY IN THE MID-UPPER 40S. THE NEXT SHORTWAVE CROSSES THE LOWER MO VALLEY INTO THE OH VALLEY MON NIGHT-TUES MORNING. FLOW ALOFT BECOMES WLY...USHERING IN DRIER AIR. HOWEVER...ONSHORE FLOW/SFC RIDGING OVER THE LOCAL AREA KEEPS LOW LEVEL MOISTURE LOCKED IN PLACE. CLOUDY CONDITIONS WILL PERSIST. SHORTWAVE AND STRONG WINDS ALOFT WILL RESULT IN UPSLOPE PRECIP OVER THE CNTRL APPALACHIANS. THE FRONT WILL ALSO REMAIN STALLED JUST OFFSHORE. WILL FOCUS LOW END CHANCE POPS ACROSS THE PIEDMONT AND IN THE SE. DETERMINISTIC MODELS AND ENSEMBLE GUIDANCE PROVIDING A WIDE RANGE OF TEMPS EARLY TUES MORNING...WITH THE NAM BEING THE COLDEST. HOWEVER...THE NAM REMAINS AN OUTLIER...SO HAVE TRENDED TOWARD GFS/ECMWF GUIDANCE. THE RESULT IS MOSTLY LIQUID PRECIP OVER THE NW. WILL NEED TO MONITOR FUTURE TRENDS TO DETERMINE THERMAL PROFILE. EVEN IF SNOW IS ABLE TO FALL...ANTICIPATE LITTLE IF ANY ACCUMULATION ATTM. LOWS IN THE MID-UPPER 30S. TEMPS ONLY REBOUND INTO THE LOW-MID 40S UNDER ONGOING CAA.
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&& .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... GFS/ECMWF REMAIN IN GOOD AGREEMENT TUESDAY NIGHT THROUGH THE DAYTIME HOURS ON FRIDAY WITH REGARD TO OVERALL PATTERN. A COLD ZONAL FLOW WILL PREVAIL ALOFT ACROSS THE REGION WEDNESDAY/THURSDAY...WITH HIGH PRESSURE BUILDING INTO AND ACROSS THE AREA. WEATHER IS EXPECTED TO BE DRY WITH TEMPERATURES AT OR SLIGHTLY BELOW NORMAL FOR LATE DECEMBER. LOW TEMPS TUESDAY NIGHT AND WEDNESDAY NIGHT AROUND 25-30 DEGREES...A BIT WARMER NEAR THE COAST. LOWS THURSDAY NIGHT IN THE UPPER 20S NW TO THE LOW-MID 30S SE...WITH MIN TEMPS EXPECTED TO OCCUR BEFORE 06Z...AS CLOUDS INCREASE OVERNIGHT. HIGH TEMPS TUESDAY THROUGH THURSDAY IN THE 40S...AND IN THE 40S ALL AREAS FRIDAY (EXCEPT SE VA/NE NC WHERE 50S LOOK LIKELY). GFS/ECMWF CONTINUE TO DIVERGE FROM NEXT FRIDAY NIGHT THROUGH SATURDAY NIGHT WITH REGARD TO TIMING OF LOW PRESSURE AND ASSOCIATED COMPLEX FRONTAL SYSTEM. GFS REMAINS 12-18 HOURS FASTER THAN ECMWF WHICH DEVELOPS A WAVE ALONG THE FRONT SATURDAY NIGHT...DELAYING THE FRONTAL PASSAGE UNTIL SUNDAY. REGARDLESS... FRIDAY NIGHT INTO SATURDAY NIGHT NEXT WEEK LOOKS TO BE UNSETTLED WITH CLOUDS AND SHOWERS. HOWEVER...TEMPERATURES WILL WARM TO ABOVE NORMAL ON SATURDAY WITH MANY AREAS POTENTIALLY IN THE 60S. && .AVIATION /09Z SUNDAY THROUGH THURSDAY/... VFR CONDS OCCURRING ACROSS THE REGION WITH MOSTLY HIGH CLOUDS BEGINNING TO OVERSPREAD THE AREA FROM THE S=SW. WINDS ARE GENERALLY LIGHT FROM THE SOUTH LESS THAN 5 KT. A COLD FRONT WILL APPROACH THE MID ATLANTIC REGION DURING THE OVERNIGHT. CLOUDS WILL INCREASE AND THICKEN TONIGHT AND RAIN IS EXPECTED TO OCCUR ACROSS THE CWA BEFORE NOON ON SUNDAY. AT THIS TIME...EXPECT VFR CONDS TO PERSIST INTO THE AFTN/EVENING WITH CIGS LOWERING TO 035-060 KFT ACROSS THE REGION AND VSBY 3-5 MI IN RAIN AND FOG. OUTLOOK...STEADY RAIN MOVES INTO THE REGION DURING THE EVENING SUNDAY WITH PERIODS OF MVFR AND TEMPO IFR CONDS SUNDAY NIGHT AND MONDAY MORNING. A LULL IN THE PRECIP IS EXPECTED MONDAY AFTN/EVENING. LOW PRESSURE MOVING ALONG THE FRONT TO THE SOUTH WILL BRING ANOTHER ROUND OF RAIN AND PSBL IFR CONDS MONDAY NIGHT INTO TUESDAY. VFR AND DRY WEATHER ARE EXPECTED WEDNESDAY AND THURSDAY. && .MARINE...
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SW FLOW AVERAGING 10-15 KT THIS MORNING...WILL TEND TO DIMINISH TO 5-10 KT LATER TODAY AS A COLD FRONT MOVES CLOSER TO THE AREA AND THE PRESSURE GRADIENT WEAKENS. SEAS AVG 2-3 FT TODAY...WITH BAY WAVES 1-2 FT. WHILE THIS FRONT IS NOT PARTICULARLY STRONG...EXPECT ENOUGH OF A NNE SURGE IN IT`S WAKE LATE TONIGHT/EARLY MON TO RAISE SCA HEADLINES FOR THE LOWER/MIDDLE BAY FOR WINDS TO 20 KT. GRADIENT WEAKENS BY MON AFTN SO ENDED THE SCA ATTM FOR NOW. DID NOT RAISE HEADLINES FOR THE COASTAL WATERS BUT EXPECT SEAS TO BUILD TO AROUND 5 FT FOR WATERS S OF CAPE CHARLES LIGHT IN N/NE 20 KT WINDS DURING THE DAY MON (3RD PERIOD). NEXT SHIFT MAY NEED TO ADD THESE ADDITIONAL HEADLINES. FOLLOWING CLOSER TO A GFS/ECMWF/CMC BLEND FOR WINDS (NAM AN OUTLIER AT DEVELOPING A MUCH STRONGER SFC LOW TUE/TUE NIGHT. THIS CONSENSUS SOLUTION STILL SUPPORTS WINDS TO INCREASE BACK TO 15-25 KT FOR MOST OF THE REGION LATE MON NIGHT/TUE WITH SEAS BUILDING TO 5-7 FT ACRS SOUTHERN COASTAL WATERS...AND 3-4 FT IN THE LOWER BAY. SFC HIGH PRESSURE SLOWLY BUILDS INTO THE AREA BY MIDWEEK...WITH WINDS/SEAS DIMINISHING TUE NIGHT/WED.
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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...
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MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 4 AM TO NOON EST MONDAY FOR ANZ631- 632-634.
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&& $$ SYNOPSIS...SAM NEAR TERM...SAM SHORT TERM...SAM LONG TERM...WRS AVIATION...LKB MARINE...LKB EQUIPMENT...

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