Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 262113 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 513 PM EDT THU MAR 26 2015 .SYNOPSIS... A COLD FRONT THAT WILL CROSS THE REGION LATE THIS EVENING AND OVERNIGHT...EXITING THE COAST BY FRIDAY MORNING. AN UPPER LEVEL DISTURBANCE WILL PASS THROUGH THE AREA LATER FRIDAY THROUGH SATURDAY NIGHT. HIGH PRESSURE RETURNS FOR SUNDAY. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... DISSIPATING LIGHT RAIN SHOWERS EXTEND FROM ROUGHLY SALISBURY MD TO EDENTON NC LATE THIS AFTN. THIS AREA OF SHOWERS WILL CONTINUE TO DIMINISH AS THEY TRACK NNE OVER THE NEXT FEW HOURS...COMING TO AN END BY SUNSET. MEANWHILE...AN APPROACHING COLD FRONT EXTENDS FROM SCNTRL PA THROUGH CNTRL TN AS OF 400 PM AND WILL CROSS THE REGION LATER THIS EVENING (AFTER 800 PM) AND OVERNIGHT...EXITING THE COAST BY MORNING. AMPLE CLEARING AND TEMPERATURES WARMING INTO THE MID 70S THIS AFTN WEST OF INTERSTATE 95 AND ALSO NW OF RICHMOND SHOULD LEAVE BEHIND JUST ENOUGH INSTABILITY BEHIND INTO THE EVENING HOURS TO KEEP A SLIGHT CHANCE OF THUNDER IN FAR NWRN COUNTIES AS THE LEADING EDGE OF PRECIP ARRIVES. OTHERWISE...THE TIMING OF THE FRONT IS NOT IDEAL TO SUPPORT THUNDER ACROSS THE REST OF THE AREA OVERNIGHT. A COLDER AIRMASS MOVES IN BEHIND THE COLD FRONT AND A BRIEF PERIOD OF BREEZY NW WINDS WITH GUSTS UP TO 25 MPH SHOULD BE ANTICIPATED. TEMPERATURES ARE EXPECTED TO FALL INTO THE LOWER 40S NW TO LOWER 50S SE BY MORNING. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/... HIGH PRESSURE STARTS TO BUILD INTO THE MID ATLANTIC REGION FROM THE NW ON FRI AS A DEEP UPPER LEVEL TROUGH DIGS INTO THE AREA...CONTINUING TO BRING A MUCH COOLER AIRMASS INTO THE AREA. HAVE LOWERED HIGH TEMPERATURES INTO THE MID-UPPER 40S BASED ON THICKNESSES...MODEL TEMPERATURE TRENDS...AND CLOUDY SKIES IN WIDESPREAD PRECIP (PROMOTING EVAPORATIVE COOLING) AS THE UPPER TROUGH NOSES INTO THE MID ATLANTIC REGION. THERE WILL BE VERY LITTLE DIURNAL TEMPERATURE CHANGES OCCURRING ON FRI AS A RESULT. THERE IS PLENTY OF MOISTURE PRESENT AND INSTABILITY AVAILABLE IN THE POST-COLD FRONT/UPPER TROUGH ENVIRONMENT TO HOLD ONTO WIDESPREAD SHOWERS FRI MORNING WHICH WILL BECOME MORE FOCUSED ALONG THE COAST BY FRI AFTN. MODEL CROSS SECTIONS SHOW MID-LEVELS OF THE ATMOSPHERE DRYING OUT DURING THE AFTN WHILE SQUEEZING OUT THE LAST BIT OF MOISTURE AVAILABLE FOR PRECIPITATION GENERATION/SUSTAINABILITY. THE NAM IS MUCH FASTER THAN THE GFS IN THIS CASE...HOWEVER THE INCOMING SHORTWAVE ENERGY ASSOCIATED WITH THE UPPER TROUGH WILL PROVIDE THE BEST LIFT FOR CONTINUED SHOWER ACTIVITY WITH THE REMNANT MOISTURE AVAILABLE DURING THE AFTN. SHOWERS REALLY DIMINISH FRI EVENING/OVERNIGHT AND TEMPS DROP INTO THE LOWER 30S NW (UPPER 20S POSSIBLE FOR FAR NWRN AREAS IN LOUISA/FLUVANNA COUNTIES) AND THE MID-UPPER 30S SE. PRECIP-TYPE WILL PRIMARILY BE IN THE FORM OF RAIN FRI NIGHT...HOWEVER SNOW (OR GRAUPEL) COULD MIX WITH RAIN ON THE WRN FRINGE OF THE PRECIP SHIELD WHERE THE COLDEST TEMPS WILL OCCUR. LITTLE TO NO ACCUMULATIONS ARE ANTICIPATED AND IMPACTS TO TRAVEL ARE NOT EXPECTED. THE UPPER TROUGH MOVES DIRECTLY OVERHEAD ON SAT/SAT NIGHT AND SO DO THE COLDEST TEMPERATURES ASSOCIATED WITH THIS AIRMASS. HIGHS ONLY EXPECTED TO REACH INTO THE MID-UPPER 40S. IF THERE ARE ANY LINGERING SHOWERS IN THE MORNING...THERE COULD STILL BE A MIX OF RAIN AND SNOW ON THE WRN EDGES OF PRECIP. AFTN INSTABILITY WITH THE TROUGH OVERHEAD WILL LIKELY RESULT IN WIDESPREAD CUMULUS WHICH MAY RESULT IN ISOLATED SHOWERS THAT SHOULD STAY CONFINED ALONG THE COAST. THERE COULD STILL BE SOME GRAUPEL MIXED WITH RAIN ACROSS THE NRN NECK AND MD EASTERN SHORE DUE TO THE CONVECTIVE NATURE OF THE PRECIP. ALL SHOWERS FINALLY COME TO AN END SAT EVENING...SKIES CLEAR...AND TEMPERATURES PLUMMET INTO THE 20S BY SUN MORNING. SFC HIGH PRESSURE MOVES ACROSS THE REGION ON SUNDAY. SUNNY SKIES WILL BE THE MAIN WEATHER HIGHLIGHT BUT THE DRY/STABLE ENVIRONMENT WITH LIGHT WEST WINDS WILL KEEP TEMPERATURES IN CHECK WITH READINGS ONLY WARMING INTO THE MID-UPPER 40S ALONG THE IMMEDIATE COAST TO THE LOWER 50S ACROSS INTERIOR VA AND ALL OF NE NC. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... OVERALL PATTERN WILL FEATURE SOME FLATTENING OF THE MID LEVEL FLOW IN THE MEDIUM RANGE WITH A WEAKER VERSION OF A MEAN UPPER RIDGE IN THE WESTERN CONUS AND AND TROUGH IN THE NE CONUS. WHAT LOOKS TO BE A FAIRLY WEAK FRONT WILL PASS THROUGH THE REGION ON MON. LATEST 12Z/26 ECMWF SHOWING A LITTLE MORE MOISTURE THAN THE GFS AS IT DIGS THE SHORTWAVE FARTHER SOUTH. WILL HAVE A SLIGHT CHC POP FOR SHOWERS FOR NOW...NO GULF CONNECTION PRESENT IN WNW FLOW ALOFT SO ANY POTENTIAL QPF AMOUNTS LOOK FAIRLY LIGHT. TEMPERATURES MON REMAIN SEASONABLE...HIGHS MAINLY IN THE 60S...A BIT COOLER OVER THE ERN SHORE. NEXT SHORTWAVE SLATED FOR THE MIDDLE OF THE WEEK WILL REMAIN FARTHER NORTH...MOVING FROM THE UPPER MIDWEST AT 12Z/TUE...TO OFF THE NEW ENGLAND COAST WED/WED NIGHT. THIS WILL BRING DRY WX TO THE LOCAL AREA TUE/WED AS LOW LEVEL FLOW SHIFTS TO THE SSW ON TUE...AND THEN TO THE W ON WED AS SFC LOW PRESSURE PASSES ACRS THE GREAT LAKES AND NE CONUS. HIGHS MAINLY IN THE 60S...ALTHOUGH SOME LOWER 70S ARE POSSIBLE WELL INLAND DEPENDING ON THE PRECISE TRACK OF THE SFC LOW. GFS/ECMWF DIVERGE BY THU...GFS BEING THE WETER SOLN AS SFC LOW PRESSURE APPROACHES FROM THE TN VALLEY WITH HIGH PRESSURE OFF THE COAST. WILL HAVE CHC POPS FOR NOW. TEMPERATURES WILL BE HIGHLY DEPENDENT ON CLOUD COVER...STAYING NEAR CLIMO AT THIS POINT WITH HIGHS MAINLY IN THE 60S TO AROUND 70 F. MORNING LOWS MON-THU AVG IN THE UPPER 30S TO UPPER 40S. && .AVIATION /21Z THURSDAY THROUGH TUESDAY/... THE CURRENT SURFACE ANALYSIS HAS A COLD FRONT EXTENDING FROM LOW PRESSURE OVER CENTRAL PENNSYLVANIA ACROSS WEST VIRGINIA TO MISSISSIPPI. A WEAK LOW PRESSURE SYSTEM WAS OVER EASTERN NORTH CAROLINA. THIS SECOND LOW WAS HELPING TO PRODUCE SHOWERS OVER EASTERN PORTIONS OF VIRGINIA AND NORTH CAROLINA AND THE MARYLAND EASTERN SHORE THURSDAY AFTN. THE LOW OVER NORTH CAROLINA WILL MOVE TO THE NORTHEAST AND PCPN IS EXPECTED TO END BY LATE AFTN. THE COLD FRONT OVER WEST VIRGINIA WILL MOVE THROUGH THE TAF SITES EARLY FRIDAY MORNING. RAIN AND MVFR OR IFR CEILINGS WILL DEVELOP BEHIND THE FRONT AND CONTINUE THROUGH MUCH OF THE DAY FRIDAY. OUTLOOK...CONDITIONS SLOWLY IMPROVE LATE FRIDAY/FRIDAY NIGHT FRIDAY AS THE WIND SHIFTS TO N/NW. ISOLATED RAIN AND SNOW SHOWERS ARE PSBL SATURDAY. OTHERWISE...MAINLY DRY AND VFR CONDITIONS ARE EXPECTED TO PREVAIL SATURDAY INTO EARLY NEXT WEEK. && .MARINE... CURRENT SFC ANALYSIS HAS SFC LOW PRESSURE OVER NRN VA/MD/SE PA...WITH FAIRLY SIGNIFICANT PRESSURE FALLS OVER THE PAST 6 HR ON THE ORDER OF 8 MB. THIS HAS ENABLED WIDESPREAD WINDS OF AROUND 20 KT ACRS THE LOWER BAY AND COASTAL WATERS DESPITE THE MARINE INVERSION DUE TO THE COLD WATERS. HIGHER GUSTS WERE OBSERVED EARLIER TODAY WITH ENHANCEMENT FROM SHOWERS/EMBEDDED TSTMS. A COLD FRONT TRACKS THROUGH THE REGION LATER TONIGHT...EVENTUALLY BRINGING SCA CONDITIONS TO ALL AREAS AS MUCH COLDER AIR RUSHES IN FROM THE NORTH. EXPECT WINDS TO SHIFT FROM THE SW TO THE N/NE 10-15KT...AND THEN INCREASE TO 20-25KT AS LOW-LEVEL CAA COMMENCES. IT WILL TAKE AWHILE HOWEVER...AND WINDS WILL ACTUALLY TEND TO RELAX A BIT THIS EVENING IN MANY AREAS. SCA`S WILL REMAIN IN EFFECT ACRS THE COASTAL WATERS DUE TO ELEVATED SEAS...AND ACRS THE LOWER BAY AND CURRITUCK SOUND (EVEN THOUGH SUB-SCA CONDITIONS MAY PREVAIL FOR MUCH OF THE EVENING AND INTO THE EARLY AM HRS FRI). WINDS FROM ABOUT 09Z THROUGH 15Z (DELAYED A FEW HRS FOR SRN WATERS) WILL AVG 20-25 KT WITH GUSTS TO 30 KT ALONG THE COAST AND BAY...TO A MORE MARGINAL 15-20 KT FOR THE RIVERS/SOUND. WIND/WAVES/SEAS SUBSIDE FOR A SHORT PERIOD OF TIME LATER FRIDAY AFTERNOON/EVENING...BEFORE ANOTHER ROUND OF MARGINAL SCA CONDITIONS ARE POSSIBLE LATER FRIDAY NIGHT THROUGH SATURDAY NIGHT (DID NOT EXTEND HEADLINES THIS FAR OUT AS THE SUB-SCA CONDITIONS HAVE A GOOD CHC TO LAST > 6 HR). HIGH PRESSURE RETURNS SUNDAY AND MOVES OFFSHORE SUNDAY NIGHT AHEAD OF ANOTHER COLD FRONT. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY FROM 4 AM TO 10 AM EDT FRIDAY FOR ANZ635>637. SMALL CRAFT ADVISORY UNTIL 4 PM EDT FRIDAY FOR ANZ632>634-650- 652-654. SMALL CRAFT ADVISORY FROM 4 AM TO 1 PM EDT FRIDAY FOR ANZ630- 631-638. SMALL CRAFT ADVISORY UNTIL 7 PM EDT FRIDAY FOR ANZ656-658. && $$ SYNOPSIS...BMD NEAR TERM...BMD SHORT TERM...BMD LONG TERM...LKB AVIATION...LSA MARINE...AJZ/LKB

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