Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 191213 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 713 AM EST WED NOV 19 2014 .SYNOPSIS... HIGH PRESSURE BUILDS ACROSS THE SOUTHEAST THROUGH TONIGHT. A WEAK...DRY FRONTAL SYSTEM WILL CROSS THE REGION THURSDAY...WITH HIGH PRESSURE REBUILDING OVER THE AREA LATER THURSDAY AND FRIDAY. HIGH PRESSURE MOVES OFFSHORE SATURDAY AHEAD OF ANOTHER COLD FRONT WHICH APPROACHES FROM THE WEST LATE IN THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... LATEST WX ANALYSIS FEATURES STRONG 1031+MB SFC HIGH OVER THE GULF COAST THIS MORNING. TO THE NORTH, LOW PRESSURE WAS ANALYZE OVER WESTERN ONTARIO MOVING TOWARDS THE UPPER GREAT LAKES. UPPER LOW WILL CONTINUE TO EJECT NEWD TOWARD ATLANTIC CANADA TODAY/TONIGHT, WITH THE ASSOCIATED SFC LOW AND CLIPPER FRONT MOVING ACROSS THE UPPER MIDWEST/GREAT LAKES LATER TODAY AND TONIGHT. MEANWHILE, SFC HIGH PRESSURE ALSO CONTINUES TO BUILD EAST TODAY, BECOMING LOCATED ALONG THE SE COAST THROUGH THURSDAY. RESULTANT LIGHT SW FLOW SHOULD ALLOW FOR SLOWLY MODERATING TEMPERATURES THROUGH THE NEAR TERM PERIOD. DESPITE THE INCREMENTAL WARMING, H85 TEMPS REMAIN -1 TO -2 STD DEV (-4 TO 0 C). THIS ALONG WITH THE FRIGID START AND MINIMAL MIXING WILL MAKE FOR ANOTHER RATHER CHILLY DAY. HIGHS STILL ~2 STD DEV BELOW NORMAL, RANGING FROM THE LOWER TO MID 40S UNDER A PARTLY TO MOSTLY SUNNY SKY. INCREASING MID-CLOUDS AND MODEST WAA AHEAD OF THE APPROACHING FRONT WILL MAKE FOR A SLIGHTLY WARMER NIGHT ACROSS THE AREA TONIGHT. EARLY MORNING LOW TEMPS IN THE MID TO UPPER 20S INLAND TO LOW 30S ALONG THE COAST. && .SHORT TERM /THURSDAY THROUGH SATURDAY/... SOME FURTHER MODERATING TO TEMPS THURSDAY OUT AS THE DRY CLIPPER FRONT PUSHES ACROSS THE LOCAL AREA THROUGH THE DAY, SETTLING SOUTH OF THE AREA THURSDAY NIGHT. LIGHT SW FLOW AND DEEPER VERTICAL MIXING SHOULD ALLOW TEMPERATURES TO WARM INTO THE UPPER 40S NORTH TO LOWER 50S SOUTH. PUSH OF COLD CANADIAN AIR WILL NOT NEARLY BE AS STRONG AS WITH THE PREVIOUS TWO FRONTAL PASSAGES. BRUNT OF CAA WILL BE DELAYED UNTIL AROUND SUNSET AND INTO THURSDAY NIGHT...WITH THE COLDEST AIR TO REMAIN TO OUR NORTH OVER THE NRN MID-ATLANTIC. EARLY MORNING LOWS FRIDAY MORNING GENERALLY IN THE 20S TO AROUND 30. UPSTREAM UPPER RIDGE OVER THE PLAINS AND INTERMOUNTAIN WEST WILL PUSH INTO THE CENTRAL CONUS FRI AS THE PERSISTENT UPPER TROUGH OVER THE ERN CONUS EJECTS OFF THE NE COAST. MEANWHILE, ~1028+MB SFC HIGH PRESSURE BUILDS INTO THE REGION FROM THE OHIO VALLEY ON FRI. MODEST CAA KNOCKS HIGH TEMPS BACK INTO THE MID-UPPER 40S FRI UNDER A MAINLY SUNNY SKY. SFC HIGH PIVOTS TOWARD THE MID-ATLANTIC COAST FRIDAY NIGHT AND OFF THE COAST ON SATURDAY. CLEAR SKY/LIGHT WINDS SHOULD BRING ANOTHER COLD NIGHT, WITH LOWS IN THE 20S INLAND TO AROUND 30 ALONG THE COAST. LLVL WINDS VEER AROUND TO THE SSE THROUGH THE DAY, WITH GRADUAL INCREASE IN MOISTURE AND MID TO HIGH CLOUDS THROUGH THE DAY. HIGHS WARM SLIGHTLY INTO THE U40S NORTH TO LOW 50S SOUTH UNDER A PARTLY SUNNY SKY. && .LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... COMPLEX SYSTEM TO AFFECT RGN LATE IN THE WEEKEND INTO EARLY NEXT WEEK. MODELS NOW IN BETTER AGREEMENT WITH DEPICTION OF LOW PRES PUSHING ACROSS THE RED RIVER VLY/NRN TX SAT NIGHT AND EARLY SUNDAY, TAKING ON A NEG TILT AS IT EJECTS NE INTO THE MID MS VLY ON SUN AND TOWARDS THE GREAT LAKES BY EARLY MONDAY. MEANWHILE, MODELS AGREE THAT ABUNDANT GULF MOISTURE GETS TRANSPORTED NORTH (AIDED BY A SRN STREAM S/W) AHEAD OF THE COLD FRONT WHICH ALLOWS FOR A WIDESPREAD OVERRUNNING RAIN EVENT INVOF THE ADVANCING WARM FRONT. ORIENTATION OF FRONTAL BNDRY WILL LIKELY BE THE DETERMINING FACTOR TEMP WISE, AND A GOOD DEAL OF UNCERTAINTY REMAINS WITH TEMPS. MODELS CONTINUE TO HINT AT PSBL IN-SITU DAMMING OVR THE PIEDMONT SUN NIGHT/ERLY MON, WHILE TEMPS IN THE U60S TO L70S OVER THE COASTAL PLAIN. UPSHOT...EXPECT A WET AND WRMR PERIOD AHEAD OF THE CDFRNT. CONTINUE WITH LIKELY POPS (RAIN) SUN AFTN AND NIGHT ACROSS THE ENTIRE FA WITH THE BULK OF BEST AFTER 18Z SUN, SHIFTING TO THE COAST SUNDAY NIGHT AS INFLUX OF DRIER AIR AT MID-LEVELS NOW WELL MODELED BY SUNDAY NIGHT. HIGHS SUN IN THE L-M50S NWRN- MOST COUNTIES TO ~70 SERN SCTNS. REMAINING MILD FOR MOST SUN NIGHT AS WARM FRONT ADVANCES NORTH ACROSS MUCH OF THE AREA. LOWS 50-60. INCRG PRES GRADIENT BEHIND WARM FRONT AND AHEAD OF COLD FRONT SHOULD RESULT IN A BREEZY TO (WINDY ALONG THE COAST) PERIOD SUNDAY NIGHT THRU MONDAY NIGHT. PCPN TYPE BECOMES MORE CONVECTIVE IN NATURE AS FA GETS INTO WARM SECTOR. CHC SHRAS AHEAD AND ALONG FROPA MON/MON NIGHT (KEPT THUNDER OUT OF FCST ATTM). WARM WITH HIGHS MON U60S-M70S. LOWS MON NIGHT DROPPING INTO THE M-U40S PIEDMONT BEHIND FROPA...55-60 SERN AREAS. SHRAS LINGER ON TUE DUE TO UPR LVL SYSTEM. HIGHS U50S-M60S. && .AVIATION /12Z WEDNESDAY THROUGH SUNDAY/...
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EXPECT MOSTLY CLEAR SKIES TODAY AS HIGH PRESSURE BUILDS INTO THE SE STATES...EXTENDING UP INTO THE MID ATLANTIC REGION...AND A COLD FRONT TRACKS ACROSS THE OHIO VALLEY. MID-HIGH LEVEL STRATUS ASSOCIATED WITH THE COLD FRONT WILL STREAM INTO THE AREA FROM THE W-NW LATE IN THE AFTN/EARLY EVENING THROUGH TONIGHT. THE FRONT CROSSES THE REGION ON THURSDAY. ALTHOUGH IT WILL BE A DRY FRONT (I.E. NO PRECIPITATION)...SW WINDS WILL BECOME GUSTY AROUND 20 KT BY THU AFTN. HIGH PRESSURE THEN SETTLES OVER THE MID ATLANTIC REGION FRI AND SAT...MOVING WELL OFFSHORE ON SUNDAY. A WET WEATHER SYSTEM IS EXPECTED TO IMPACT THE REGION SUNDAY THROUGH MONDAY NIGHT.
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&& .MARINE...
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UPDATE...EXTENDED SCA FOR SRN CHES BAY WHERE WINDS WILL STAY AROUND 15-20KT FOR THE NEXT FEW HOURS BEFORE DIMINISHING. MAIN IMPACT AREAS ARE THE MOUTH OF THE BAY AND ERN CHES BAY FROM PLANTATION FLATS/CAPE CHARLES TO THE BAY BRIDGE TUNNEL. ADDED NEXT ROUND OF SCA HEADLINES FOR PRIMARILY TONIGHT THROUGH THU NIGHT. SEE DISCUSSION BELOW FOR DETAILS. PREVIOUS DISCUSSION...SCA`S EXTENDED FOR COASTAL WATERS UNTIL 7 AM EDT. WIND GUSTS ARE STILL AROUND 25KT IN PRE-DAWN DIURNAL SURGE. CANCELLED SCA FOR FAR SRN WATERS AND CURRITUCK SOUND SINCE WINDS/SEAS HAVE DROPPED BELOW SCA THRESHOLDS. STILL EXPECTING ALL SCA FLAGS TO EXPIRE AT 7 AM EDT AS THE PRE-DAWN DIURNAL SURGE AND SEAS DIMINISH AS HIGH PRESSURE BUILDS INTO THE SE STATES AND EXTENDS OVER THE WATERS OF THE MID ATLANTIC REGION TODAY. WEST WINDS THIS MORNING TURN MORE SWLY BY THIS AFTN AND SPEEDS WILL BEGIN TO INCREASE AGAIN AHEAD OF AN APPROACHING COLD FRONT. A TIGHTENING PRESSURE GRADIENT AND JET SUPPORT ALOFT WILL CREATE JUST THE RIGHT CONDITIONS FOR A S-SW SURGE THIS EVENING/TONIGHT. SPEEDS INCREASING TO 20-30KT WILL ONCE AGAIN PLACE THE WATERS WITHIN SOLID SCA CONDITIONS. SEAS/WAVES AVERAGE 3-4FT TONIGHT...SEAS 4-5FT COASTAL WATERS NORTH OF PARRAMORE ISLAND. WARM AIR ADVECTION PROCESSES WILL LIKELY LIMIT FULL MIXING POTENTIAL TONIGHT SO GALE FORCE GUSTS ARE NOT ANTICIPATED AT THIS TIME... ESPECIALLY SINCE LARGE PRESSURE DIFFERENCES WILL NOT BE PRESENT. THE COLD FRONT CROSSES THE WATERS ON THU...FOLLOWED BY A REINFORCING SHOT OF COLDER AIR ACROSS THE NRN WATERS THU NIGHT INTO FRI MORNING. A BRIEF LULL IN SCA WIND SPEEDS IS POSSIBLE THU AFTN...BUT ANOTHER SURGE IS EXPECTED BEHIND THE FRONTAL PASSAGE THU NIGHT AS SW WINDS TURN TO THE NW. SEAS/WAVES SHOULD CONTINUE TO AVERAGE 3-4FT...WITH UP TO 5FT SEAS POSSIBLE NEAR BUOY 44009 DURING THE NW SURGE THU NIGHT. SCA FLAGS WILL BE ISSUED FOR TONIGHT THROUGH THU NIGHT WITH THE 7 AM UPDATE...WHEN CURRENT HEADLINES EXPIRE. HIGH PRESSURE SETTLES OVER THE MID ATLANTIC REGION FRI AND SAT... MOVING WELL OFFSHORE ON SUNDAY. A WET WEATHER SYSTEM IS EXPECTED TO IMPACT THE REGION SUNDAY THROUGH MONDAY NIGHT.
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&& .CLIMATE... ANOTHER ROUND OF UNSEASONABLY COLD WX IS EXPECTED THROUGH WEDNESDAY. RECORD LOW MINIMUM TEMPERATURE THIS MORNING RIC 18/1936 ORF 25/1959 SBY 17/1936 ECG 21/1959 WED...RECORD LOW MAXIMUM TEMPERATURE RIC 37/1951 ORF 38/1951 SBY 35/1951 ECG 39/1951 && .AKQ WATCHES/WARNINGS/ADVISORIES...
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MD...NONE. NC...FREEZE WARNING UNTIL 9 AM EST THIS MORNING FOR NCZ102. VA...NONE. MARINE...SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 10 AM EST THURSDAY FOR ANZ635>638. SMALL CRAFT ADVISORY UNTIL 9 AM EST THIS MORNING FOR ANZ632- 634. SMALL CRAFT ADVISORY FROM 7 PM THIS EVENING TO 7 AM EST FRIDAY FOR ANZ630>632-634-650-652-654. SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 7 AM EST FRIDAY FOR ANZ633. SMALL CRAFT ADVISORY FROM MIDNIGHT TONIGHT TO 4 AM EST FRIDAY FOR ANZ656-658.
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&& $$ SYNOPSIS...MAM NEAR TERM...MAM SHORT TERM...MAM/SAM LONG TERM...MPR AVIATION...BMD MARINE...BMD CLIMATE...AKQ

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