Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 261829 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 229 PM EDT TUE MAY 26 2015 .SYNOPSIS... HIGH PRESSURE REMAINS ANCHORED OFF THE MID ATLANTIC COAST INTO THE WEEKEND. A TROUGH OF LOW PRESSURE REMAINS NEARLY STATIONARY EAST OF THE MOUNTAINS THROUGH THE END OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... CRNT FCST ON TRACK WITH ONLY MINOR CHANGES MADE TO THE GRIDS TODAY. INCRG LL MSTR RESULTING IN SCT-BKN SC/CU LATE THIS AM. OFFSHORE RIDGE HOLDING FIRM WHILE WEAK S/W ENERGY CONTS TO TRACK NE ACROSS THE MTS. LTST HIGH RES DATA SUGGESTS SCT CONVECTION DVLPS ACROSS THE MTS IVOF SFC TROF DVLPMNT. A FEW ECHOES MAY CROSS XTREME WRN MOST CNTYS AFTR 4 PM. OTW...A PT TO MSTLY SUNNY AND WARM AFTRN AHEAD. HIGHS IN THE L-M80S XCPT REMAINING IN THE 70S AT THE BEACHES. && .SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY NIGHT/... ANY REMNANT CONVECTION OVER THE EASTERN PIEDMONT WILL DISSIPATE SHORTLY AFTER SUNSET TONIGHT WITH THE LOSS OF DAYTIME HEATING. OTHERWISE...EXPECT A WARM NIGHT TONIGHT WITH LOWS GENERALLY 65-70 WITH A LIGHT TO SLIGHTLY BREEZY SOUTH WIND. THE BERMUDA HIGH REMAINS STEADFAST OFF THE EAST COAST THROUGH THE THURSDAY NIGHT PERIOD. MEANWHILE...A TROUGH OF LOW PRESSURE MOVES ACROSS THE GREAT LAKES TONIGHT AND WED...AND THEN ALONG THE ST LAWRENCE RIVER VALLEY WED NIGHT/THU. THIS TROUGH WILL BE A KEY PLAYER IN THE WEATHER ACROSS THE MID ATLANTIC REGION FROM WED THROUGH THU NIGHT. THE AFOREMENTIONED TROUGH WILL BREAK DOWN MID/UPPER LEVEL RIDGING AND FLATTEN THE AXIS TO BE MORE IN LINE WITH THE SE COAST FROM NORTH CAROLINA TO FLORIDA. THIS WILL ALLOW INCREASING MOISTURE FROM THE ATLANTIC AND GULF OF MEXICO TO STREAM INTO THE AREA AND ALSO FOR WAA PROCESSES TO ERODE AWAY AT THE DRIER AND MORE STABLE AIRMASS THAT HAS BEEN IN PLACE SINCE THE PAST WEEKEND. THE END RESULT WILL BE INCREASING POTENTIAL FOR AFTN/EVENING THUNDERSTORMS (SHIFTING FROM WEST TO EAST EACH DAY) AS REMNANT SHORTWAVE ENERGY FROM MCS ACTIVITY IN THE GULF COAST STATES ROUNDS THE TROUGH AND RIDES UP INTO THE REGION ON THE WRN PERIPHERY OF THE MID/UPPER RIDGE. THE POTENTIAL FOR THUNDERSTORMS ALONG SEABREEZE BOUNDARIES CANNOT BE RULED OUT HOWEVER. ALSO... EXPECT INCREASING HIGH/LOW TEMPS AND DEWPOINTS AS WAA PROCESSES BEGIN TO ERODE AWAY AT THE DRIER AND MORE STABLE AIRMASS THAT HAS BEEN IN PLACE SINCE THIS PAST WEEKEND. INCREASED MOISTURE (VIA DEWPOINTS AND INCOMING SHORTWAVES)...INCREASED PWATS TO 1.50-2.00 INCHES...SATURATED SOUNDING PROFILES ABOVE 700-500MB...AND WEAK STEERING FLOW ALOFT ALL SUGGEST THAT HEAVY RAINFALL WILL BE THE MAIN IMPACT WITH ANY STORMS THAT DEVELOP. HIGH TEMPERATURES WILL BE IN THE MID-UPPER 80S WED/THU (ABOUT 5-10 DEGREES ABOVE NORMAL). EXPECT TEMPS TO BE IN THE LOW-MID 80S AT THE BEACHES. LOW TEMPS WED/THU NIGHTS 65-70. && .LONG TERM /FRIDAY THROUGH MONDAY/... THE LONG TERM PERIOD WILL BE CHARACTERIZED BY ABOVE NORMAL TEMPS EACH DAY AND TYPICAL DIURNAL CHANCES FOR TSTMS...ESPECIALLY ACROSS NW AREAS. UPPER LEVEL RIDGING WILL SLOWLY BREAK DOWN DURING THE PERIOD. A COLD FRONT IS EXPECTED TO SLOWLY APPROACH FROM THE NW AND SETTLE OVER THE MID ATLANTIC STATES BY LATE IN THE UPCOMING WEEKEND INTO EARLY NEXT WEEK. GUIDANCE HAS H85 TEMPERATURES GETTING NO HIGHER THAN 16C. CLOUD COVER...ESPECIALLY SUNDAY AND MONDAY...WILL ALSO HOLD READINGS DOWN. HIGH TEMPERATURES ARE FORECAST TO RANGE FROM 85 TO 90 INLAND AND UPR 70S TO LWR 80S NEAR THE COAST. IT WILL BE MODERATELY HUMID WITH DEW POINTS IN THE MID TO UPR 60S. LOW TEMPERATURES ARE EXPECTED TO BE 65-70 DEGREES. && .AVIATION /19Z TUESDAY THROUGH SUNDAY/... HIGH PRESSURE OFF THE MID ATLANTIC COAST WILL CONTINUE TO BRING S/SW WINDS DURING THE 18Z TAF PERIOD...OCCASIONALLY GUSTING TO AROUND 15 TO 20 KNOTS. AN ISOLATED SHOWER OR TSTM WILL BE POSSIBLE LATE THIS AFTN AND TONIGHT WELL INLAND...BUT IS UNLIKELY TO AFFECT ANY OF THE TERMINALS. ANY CONVECTION WEDNESDAY IS EXPECTED TO HOLD OFF UNTIL AFT 18Z. SOME MVFR DEVELOPED THIS MORNING OVER SE NORTH CAROLINA AND SCT TO BKN STRATOCU AND CUMULUS CIGS ABOVE 3K FT HAVE BEEN REPORTED AT THE TAF SITES. MOS OUTPUT AND NAM BUFR SOUNDINGS INDICATE SUB VFR CONDS MAY OCCUR WEDNESDAY MORNING BUT GUIDANCE IS RATHER INCONSISTENT. TAFS ARE BASED PRIMARILY ON TRENDS OF THE NAM BUFR SOUNDINGS WHICH EMPHASIZE MVFR CIGS. WITH DEW POINTS WELL INTO THE 60S...WOULD EXPECT SOME PERIODS OF MVFR VSBYS AS WELL...MAINLY BETWEEN 10 AND 15Z. OUTLOOK...BERMUDA HIGH PRESSURE WILL CONTINUE TO DOMINATE...BUT LATE AFTN/EVENING TSTMS ARE EXPECTED LATE WEDNESDAY AND AGAIN THURSDAY WITH LESSER CHANCES FRIDAY AND SATURDAY. CHANCES INCREASE AGAIN SUNDAY. OUTSIDE OF TSTMS... VFR CONDITIONS SHOULD PREVAIL...SOME MVFR AND PATCHY IFR CIGS/VSBYS WILL BE LIKELY FOR A FEW HOURS AROUND SUNRISE. && .MARINE... 10 AM UPDATE...ISSUED SCA FOR 1 PM TO 1 AM FOR THE BAY AS MODEL GUIDANCE IS MORE SUPPORTIVE FOR INCREASING WINDS TO NEAR 20 KNOTS LATE THIS AFTERNOON THROUGH THE EVENING HOURS. LATEST NAM12 SHOWS PRESSURE GRADIENT TIGHTENING OVER THE SAME AREA LATER TODAY. ALSO WINDS INCREASED TO NEAR SCA AT A FEW LOCATIONS MONDAY EVENING AND MODELS INDICATE STRONGER WINDS THIS EVENING AS COMPARED WITH MONDAY EVENING. WILL EVALUATE FOR THE RIVERS BUT AT THIS TIME...IT APPEARS THAT LATEST DATA TRENDS AND THE LACK OF FETCH WITH A SOUTH WIND ARE NOT SUPPORTIVE OF SCA. PREVIOUS DISCUSSION... SFC HIGH PRESSURE TO REMAIN CENTERED WELL OFF THE MID ATLC COAST THE NEXT FEW DAYS...WITH LOW PRESSURE MOVING ACRS ONTARIO CANADA. SOUTHERLY FLOW WILL PREVAIL...WITH SOME MINOR DIRECTION CHANGES ON A DIURNAL BASIS (SSE MIDDAY THROUGH EVENING TO SSW OVERNIGHT THROUGH THE MORNING). PRESSURE GRADIENT TODAY AND WED IS TIGHT ENOUGH THAT WINDS SHOULD AVG 10 TO 15 KT...WITH SOME INCREASE IN THE LATE AFTN/EVENING RESULTING IN GUSTS TO 20 KT. OVERALL STILL FEEL THIS IS TOO MARGINAL TO RAISE ANY SCA HEADLINES ACRS THE BAY/RIVERS/SOUND BUT BOATING CONDITIONS WILL NOT BE IDEAL AND WAVES IN THE BAY WILL BE SOMEWHAT ELEVATED AT 2-3 FT WITH COASTAL SEAS BUILDING TO 3-4 FT. GRADIENT WEAKENS A BIT ON THU...AND WINDS SHOULD BE A FEW KT LESS OVERALL. WINDS LOOK TO REMAIN SOUTHERLY FOR THE MOST PART INTO THE UPCOMING WEEKEND. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 1 AM EDT WEDNESDAY FOR ANZ630>632- 634. && $$ SYNOPSIS...BMD NEAR TERM...BMD/MPR SHORT TERM...BMD LONG TERM...LSA AVIATION...LSA MARINE...LKB/MAS/LSA

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