Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 252055 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 455 PM EDT SAT MAY 25 2013 .SYNOPSIS... HIGH PRESSURE FROM THE GREAT LAKES AND OHIO VALLEY WILL CONTINUE TO BUILD INTO THE MID ATLANTIC THIS WEEKEND...RESULTING IN DRY AND COOL CONDITIONS. A WARMING TREND WILL BEGIN MEMORIAL DAY AND LAST THROUGH NEXT WEEK AS THE HIGH BECOMES SITUATED OFF THE EAST COAST. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... LATEST SFC ANALYSIS DEPICTS SFC LOW PRESSURE DEEPENING OFF THE COAST OF SOUTHERN MAINE...AS THE UPPER LEVEL CUTOFF LOW SPINS OVER SOUTHERN NEW ENGLAND/EASTERN NY STATE. MCS SITUATED OVER THE MID MS VALLEY HAS WEAKENED THIS AFTN AS IT ENCOUNTERED DRIER AIR OVER THE OH/TN VALLEY. STILL SOME HIGH CLOUDS OVER PORTIONS OF THE CWA THIS AFTN...ALONG WITH BREEZY NW WINDS. QUITE COOL FOR MEMORIAL DAY WEEKEND WITH AFTN OBS HOLDING IN THE 60S FOR MOST LOCATIONS. EXPECT SKIES TO BECOME MAINLY CLEAR THIS EVENING AS HIGH CLOUDS ARE SHUNTED SOUTH IN THE NW FLOW ALOFT. DIMINISHING WINDS AND CLEAR SKIES WILL LEAD TO MINS TONIGHT ABOUT 15 DEGREES COLDER THAN NORMAL/MAINLY 40-45 WELL INLAND AND 45 TO 50 NEAR THE COAST. THIS WILL BE NEAR BUT JUST ABOVE RECORD LOWS (SEE CLIMATE SECTION BELOW). && .SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/... MID/UPPER LEVEL PATTERN WILL BE SLOW TO EVOLVE OVER THE NEXT FEW DAYS...WITH RIDGING DOWNSTREAM OVER THE CENTRAL CONUS AND A CUTOFF LOW GRADUALLY PUSHING NE AND OFF THE NEW ENGLAND COAST BY SUN AFTN. AT THE SFC...PRESSURE GRADIENT WILL RELAX QUITE A BIT BY SUN AFTN AS THE COASTAL LOW MOVES OFF TO THE CANADIAN MARITIMES AND HIGH PRESSURE BUILDS SE FROM THE GREAT LAKES. IN TERMS OF SENSIBLE WX ON SUNDAY...WINDS WILL BE LIGHTER AND SKIES WILL GENLY BE SUNNY. AFTER A VERY COOL START...TEMPERATURES WILL WARM RAPIDLY WITH HIGHS 70-75 FOR MOST OF THE REGION (COOLEST NEAR THE COAST AND WARMEST ALONG/WEST OF I-95). NOTE...STAYED ON COOL SIDE OF GUIDANCE AS MAV NUMBERS/MOS GUIDANCE HAVE GENLY BEEN TOO WARM PAST FEW DAYS. STILL CHILLY SUN NIGHT UNDER MAINLY CLEAR SKIES AND LIGHT WINDS BUT WITH AIRMASS MODIFYING...EXPECT MINS TO BE A FEW DEGREES WARMER THAN SAT NIGHT...WENT CLOSE TO MAV NUMBERS WITH LOWS PRIMARILY FROM THE MID TO UPPER 40S. STALLED FRONTAL BOUNDARY OVER THE GULF STATES WILL BEGIN TO LIFT NORTHWARD LATE SUN AND MON WHILE AT THE SAME TIME...UPR LVL RIDGE WILL FINALLY PROGRESS EWD. AS A RESULT...A MORE SIGNIFICANT WARMING TREND WILL COMMENCE ON MON. AS THE RIDGE PROGRESSES EWD...A WARM/MOIST AIRMASS WILL INTERACT WITH THE BOUNDARY TO PRODUCE SHOWERS AND THUNDERSTORMS OVER THE MIDWEST INTO THE OH VALLEY MONDAY AFTERNOON. STILL LOOKS TOO DRY/STABLE E OF THE MTNS SO WILL KEEP FORECAST DRY W/ JUST SOME SCATTERED AFTN CUMULUS ANTICIPATED. HIGHS RANGE FROM THE UPPER 70S/NEAR 80 ALONG AND WEST OF I-95 TO THE LOWER 70S NEAR THE COAST. ANY CONVECTIVE ACTIVITY TO THE WEST MAY FORM INTO A MESOSCALE CONVECTIVE SYSTEM. MCS WILL ROUND THE RIDGE...BUT WILL LIKELY DIE OUT BEFORE REACHING THE MID ATLC. BOUNDARY WILL CONTINUE TO LIFT NWD MON NGT...MUCH MILDER WITH LOWS FROM THE MID 50S TO THE LOWER 60S. BOUNDARY SETS UP SOMEWHERE ACRS THE AREA ON TUE...NAM DEPICTS A LOT MORE MOISTURE THAN THE GFS/ECMWF...BUT BOTH SUGGEST ENOUGH MOISTURE TO INCLUDE AT LEAST A 20 TO 30% FOR FOR SHRA AND AFTN TSRA ACRS THE CWA. HIGHS MAINLY 80-85 UNDER PARTLY TO MOSTLY CLOUDY SKIES AND INCREASING SOUTHERLY FLOW. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... HIGH PRESSURE RIDGING OVER THE EAST AND RESULTANT ABOVE NORMAL DAYTIME TEMPS WILL HEADLINE THE EXTENDED PERIOD. STRONG UPPER TROUGH WILL CONTINUE TO DIG OVER THE WRN CONUS WEDS...FURTHER AMPLIFYING THE CNTRL/ERN CONUS RIDGE AS IT PROGRESSES EWD. RIDGE AXIS WILL LOCATE FROM THE SE STATES NWWD INTO THE NRN PLAINS...PROGRESSING EWD OVER THE MID ATLANTIC INTO THE GREAT LAKES REGION THURS AFTERNOON. STRONG UPPER BERMUDA HIGH (+1 STD DEV) PROGGED TO CENTER JUST OFF THE NC COAST THURS AFTERNOON. THEREAFTER...MEDIUM RANGE MODELS IN POOR/FAIR AGREEMENT WITH UPPER LEVEL PATTERN. MAIN ERROR REGION LOOKS TO BE OVER CNTRL QUEBEC ASSOCIATED WITH A SHORTWAVE TRAVERSING SE CANADA (LARGE MODEL SPREAD IN ENSEMBLE RUNS). MODELS AGREE ON COMPRESSING THE RIDGE OVER THE NE STATES...BUT 25/00Z ECMWF IS MORE AMPLIFIED WITH THE RIDGE AXIS. THE SUBSEQUENT SENSIBLE WEATHER IMPACT WILL BE THE LOCATION OF THE BOUNDARY OVER THE NE STATES. REGARDLESS OF THE DIFFERENCES...FRONT EXPECTED TO REMAIN WELL TO THE NORTH OF THE LOCAL AREA WED-FRI. THUS...EXPECT WARM/MOIST SUMMER-LIKE AIRMASS TO ANCHOR OVER THE REGION. +1 STD DEV H5 AND H85 HEIGHTS (AS WELL AS +1 STD DEV H85 TEMPS) WILL TRANSLATE TO TEMPS +1 STD DEV (GENERALLY IN THE MID/UPPER 80S) WED-SAT. DEWPOINTS WILL ALSO INCREASE INTO THE MID 60S...AS PRECIP WATERS PROGGED TO BE AROUND 1.25 TO 1.5 INCHES WED AFTERNOON BEFORE DECREASING THURS. COMBINATION OF WARM/HUMID AND UNSTABLE AIRMASS MAY BE ENOUGH TO INTERACT WITH WEAK LEE SIDE TROUGHING FOR DIURNALLY DRIVER SHOWERS AND THUNDERSTORMS. HOWEVER...CONFIDENCE IS NOT HIGH ATTM SO WILL LIMIT POPS BELOW SLIGHT CHANCE. DECREASING MOISTURE THUR-SAT WILL INHIBIT ANY CHANCES FOR PRECIP. && .AVIATION /21Z SATURDAY THROUGH THURSDAY/... IMPRESSIVE UPR TROF FOR THIS TIME OF YEAR OVER NEW ENGLAND WILL SLOWLY BE LIFTING NORTHEAST AWAY FROM THE AREA. THIS WILL PUSH THE LOW PRESSURE OFF THE NEW ENGLAND COAST NORTHEAST AWAY FROM THE AREA TONIGHT AND SUNDAY. MAIN ISSUE IN THE FORECAST THIS AFTERNOON IS WIND SPEED AND GUSTS. LOOKING AT BUFKIT SOUNDINGS AND CURRENT OBSERVATIONS WILL GENERALLY HAVE WINDS 10 TO 15 KTS FROM THE NW WITH GUSTS FROM 20 TO 25 KTS. THE STRONGEST GUSTS WILL BE NEAR SBY. AFTER SUNSET THE WINDS WILL DIMINISH QUICKLY AND BE AROUND 10 KTS ON SUNDAY. THE DIRECTION WILL BE NORTHWEST THROUGH SUNDAY. CONTINUED MAINLY CLEAR SKIES THROUGH SUNDAY. SOME CIRRUS CLOUDS COMING OFF THE MOUNTAINS INTO RIC THIS AFTERNOON MAY ALSO CROSS PHF. STILL LOOKING AT VFR CONDITIONS ON MEMORIAL DAY THEN WITH A WARM FRONT APPROACHING FOR TUESDAY COULD DEVELOP SCATTERED THUNDERSTORMS WITH POTENTIAL MVFR IN THE STORMS. && .MARINE...
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LOW PRESSURE WILL CONTINUE TO LIFT UP THE NE COAST TONIGHT AS HIGH PRESSURE CONTINUES TO BUILD OVER THE OH VALLEY. CAA (850 TEMPS 2-3 STD DEV) WILL CONTINUE TO RESULT IN STRONG NW WINDS OVER THE WATERS THIS EVENING. HOWEVER...WITH HIGH PRESSURE BEGINNING TO EXTEND INTO THE SE STATES...THE GRADIENT OVER THE SRN COASTAL WATERS AND CURRITUCK SOUND HAS RELAXED...WITH OBSERVED SPEEDS 10 TO 15 KT. SEAS HAVE ALSO FALLEN BELOW 4 FT. WILL END THE SCA HEADLINES AT 6 PM EDT FOR THE SOUTHERN COASTAL ZONES AS WELL AS THE CURRITUCK SOUND AS A RESULT. OTHERWISE...NW WINDS 15 TO 20 KT OVER THE BAY AND 20 TO 25 KT OVER THE NRN COASTAL WATERS. SCA SPEEDS ARE BORDERLINE OVER THE NRN COASTAL WATERS...BUT SEAS OF 5 FT STILL EXPECTED 20 NM OUT THROUGH THE OVERNIGHT. SCA HEADLINES WILL DROP OFF EARLY SUNDAY MORNING AS HIGH PRESSURE BUILDS OVER THE LOCAL AREA AND THE PRESSURE GRADIENT RELAXES. A FEW SCA GUSTS MAY CONTINUE THROUGH MID MORNING ACROSS THE NRN BAY. THEREAFTER...AN EXTENDED PERIOD OF SUB SCA CONDS EXPECTED OVER THE WATERS AS HIGH PRESSURE CONTINUES TO BUILD OVER THE REGION THROUGH THE MEMORIAL DAY WEEKEND. HIGH PRESSURE WILL SLIDE OFFSHORE TUESDAY AS A WARM FRONT LIFTS OVER THE WATERS...WITH HIGH PRESSURE REMAINING JUST OFF THE SOUTHEAST COAST THROUGH THE REMAINDER OF THE WEEK.
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&& .CLIMATE... SET A RECORD LOW AT ELIZABETH CITY NC THIS MORNING AT 43 F (OLD RECORD HAD BEEN 47). MAY COME CLOSE TO CHALLENGING A FEW RECORD LOWS AGAIN SUNDAY...RECORD LOWS FOR MAY 26TH ARE LISTED BELOW: .RICHMOND............42 (1925) .NORFOLK.............47 (1967) .SALISBURY MD........39 (1917) .ELIZABETH CITY NC...44 (1967) && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 10 PM EDT THIS EVENING FOR ANZ635>638. SMALL CRAFT ADVISORY UNTIL 6 AM EDT SUNDAY FOR ANZ630>632-634- 650-652. SMALL CRAFT ADVISORY UNTIL 6 PM EDT THIS EVENING FOR ANZ633- 654-656-658. && $$ SYNOPSIS...LKB NEAR TERM...LKB SHORT TERM...LKB LONG TERM...SAM AVIATION...JAB MARINE...SAM CLIMATE...

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