Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 202004 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 404 PM EDT WED AUG 20 2014 .SYNOPSIS...
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A WARM FRONT SLOWLY LIFTS THROUGH THE REGION TONIGHT AND STALLS NEAR THE COAST THURSDAY. A WEAK AREA OF LOW PRESSURE TRACKS ACROSS THE NORTHERN MID ATLANTIC THURSDAY NIGHT...FOLLOWED BY ANOTHER LOW PRESSURE SYSTEM FRIDAY NIGHT AND AN ASSOCIATED COLD FRONT. HIGH PRESSURE BUILDS SOUTH FROM NEW ENGLAND OVER THE WEEKEND AS THE FRONT PUSHES SOUTH OF THE REGION.
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&& .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
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THE LATEST SURFACE ANALYSIS INDICATES A BROAD ~1010MB LOW OVER THE GREAT LAKES WITH A WARM FRONT EXTENDING S THROUGH THE OHIO VALLEY AND CENTRAL APPALACHIANS. GOES WV IMAGERY INDICATES A SHORTWAVE TROUGH AXIS EXTENDING S FROM THE MAIN MID-LEVEL LOW OVER THE GREAT LAKES IN VICINITY OF THE SURFACE BOUNDARY. ISO-SCT CONVECTION HAS DEVELOPED AHEAD OF THE TROUGH AXIS...WITH THE MOST ORGANIZED ACTIVITY N OF THE LOCAL AREA FROM NRN VA INTO S-CENTRAL PA. THE WARM FRONT AND MID-LEVEL TROUGH WILL SLOWLY TRACK W-E ACROSS THE REGION THIS EVENING AND OVERNIGHT. A 20-30% POP WILL BE INCLUDED TO ACCOUNT FOR THIS. OTHERWISE...EXPECT A WARM HUMID NIGHT WITH LOWS IN THE UPPER 60S TO LOW 70S. PATCHY FOG/STRATUS IS POSSIBLE LATE GIVEN ABUNDANT LOW-LEVEL MOISTURE AND LIGHT S FLOW.
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&& .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
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THE WARM FRONT STALLS IN VICINITY OF THE COAST THURSDAY. OVERALL FORCING FOR CONVECTION IS WEAK. HOWEVER...A 20% POP WILL BE MAINTAINED FOR THE EASTERN THIRD OF THE AREA DUE TO THE PRESENCE OF THE SURFACE BOUNDARY. NW MID-LEVEL FLOW DEVELOPS THROUGH THE DAY THURSDAY...WITH A WEAK IMPULSE PASSING THROUGH THE MID-ATLANTIC THURSDAY NIGHT. THE BEST CHC OF SHOWERS/TSTMS SHOULD BE ACROSS NRN PORTIONS IN CLOSER PROXIMITY TO THE SURFACE LOW. A MORE VIGOROUS WAVE DROPS ACROSS THE REGION FRIDAY AFTERNOON/FRIDAY NIGHT ALONG WITH AN ASSOCIATED COLD FRONT. THIS SHOULD PROVIDE BEST CHC OF AND GREATEST AREAL COVERAGE OF SHOWERS/TSTMS ACROSS THE LOCAL AREA DURING THE SHORT-TERM PERIOD DUE TO STRONGER UPPER JET SUPPORT. HIGH PRESSURE BUILD OVER NEW ENGLAND SATURDAY AND PUSHES S INTO THE MID-ATLANTIC. THIS WILL PUSH THE FRONT S OF THE AREA. AT THIS TIME...POPS RANGE FORM SLIGHT CHC OVER NE PORTIONS TO CHC ACROSS S/SW PORTIONS. HIGHS SHOULD GENERALLY BE IN THE UPPER 80S/LOW 90S THURSDAY/FRIDAY...BEFORE DROPPING BACK INTO THE LOW/MID 80S (POSSIBLY UPPER 70S FAR NE) SATURDAY BEHIND THE FRONT. LOWS SHOULD MAINLY BE IN THE UPPER 60S TO LOW 70S FRIDAY AND SATURDAY MORNINGS.
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&& .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
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DECREASING CHANCES FOR PRECIP AND NEAR SEASONABLE...LATE SUMMER TEMPERATURES EXPECTED THRU THE EXTENDED PERIOD FORECAST. UPPER FLOW CONTINUES TO BE DOMINATED BY BUILDING HIGH PRESSURE OVER THE CNTRL CONUS AND LOW PRESSURE/TROUGHING OFF THE NE COAST. FLOW REMAINS BLOCKED OVER ERN CANADA AND THE NERN US...RESULTING IN LITTLE PROGRESSION OF THE CNTRL CONUS RIDGE THRU THE PERIOD. THE RESULT WILL BE ONGOING NWLY FLOW INTO THE EARLY PERIOD. BACKDOOR FRONT WILL PUSH WELL SOUTH OF THE LOCAL AREA SUN AS THE TROUGH AMPLIFIES ALONG THE ERN SEABOARD. LATEST MODEL GUIDANCE HAS TRENDED SLIGHTLY WETTER SUN AFTER PREVIOUSLY BRINGING IN DRIER AIR BEHIND THE FRONT. SFC HIGH PRESSURE OVER THE NE STATES WILL RIDGE SWD OVER THE LOCAL AREA IN WAKE OF THE FRONT...WITH SUBSIDENCE INDICATED IN MODEL SOUNDINGS. MOISTURE ALSO LOOKS TO BE ON THE DOWNTREND AS MODEL DERIVED PWATS DROP BELOW 1.5 INCHES. WITH THAT SAID...SUN MAY END UP BEING DRY...BUT WILL RETAIN SLIGHT CHANCE POPS OVER THE PIEDMONT AND COASTAL AREAS AS DISTURBANCES IN NWLY FLOW AND MODEL UNCERTAINTY DECREASE CONFIDENCE. BETTER CONFIDENCE IN DRY CONDITIONS HEADING INTO EARLY NEXT WEEK AS THE CNTRL CONUS HIGH BEGINS TO NUDGE IN FROM THE WEST AND SUBSIDENCE ALOFT WINS OUT. BEST MOISTURE ALSO GETS SHUNTED TO THE SOUTH AND WEST. TREND CONTINUES INTO TUES AND WEDS AS HIGH PRESSURE BUILDS OVERHEAD AND DRY AIR AND SUBSIDENCE WIN OUT. ONSHORE FLOW AND LOW-LEVEL THICKNESSES YIELD DAYTIME TEMPS GENERALLY IN THE UPPER 70S TO LOWER 80S THRU TUES (-1 STD DEV FOR THIS TIME OF YEAR). RETURN FLOW ON WEDS AND WARMING THICKNESSES PUSH TEMPS BACK INTO THE MID 80S. LOWS GENERALLY IN THE LOW-MID 60S THRU THE PERIOD AS DEWPOINTS REMAIN IN THE LOW-MID 60S.
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&& .AVIATION /20Z WEDNESDAY THROUGH MONDAY/... A WEAK WARM FRONT WILL PUSH INTO AND ACRS THE REGION FM THE W LATE THIS AFTN INTO THU. EXPECT MAINLY VFR/MVFR CONDITIONS DURING MOST OF THE TAF PERIOD...WITH ISLTD/SCTD PCPN POSSIBLE LATE THIS AFTN INTO EARLY THU MORNG. ISLTD IFR CONDITIONS POSSIBLE LATE TNGT INTO EARLY THU MORNG...AS LIGHT ESE WINDS BECOME LIGHT SSW. LWR CIGS AND VSBYS POSSIBLE THU NGT THRU SAT...DUE TO DECENT CHC FOR SHOWERS/TSTMS. && .MARINE...
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LOW PRESSURE OFFSHORE AND HIGH PRESSURE RIDGING IN FROM THE NORTH HAS RESULTED IN ONSHORE FLOW OVER THE WATERS THIS AFTERNOON. SPEEDS AVG AROUND 10 KT WITH SEAS GENERALLY 3 FT AND WAVES 2 FT. WARM FRONT WILL APPROACH THE WATERS TONIGHT FROM THE WEST AS THE RIDGE AXIS AND SFC LOW PUSH FARTHER OUT TO SEA. THIS WILL VEER THE FLOW AROUND TO THE SOUTH OVERNIGHT...AVG 10 KT. SEAS WILL BEGIN TO SUBSIDE TO 2-3 FT AND WAVES 1-2 FT. FRONTAL BOUNDARY STALLS NEAR THE WATERS THURS AS ANOTHER WAVE OF LOW PRESSURE DEVELOPS OVER THE WATERS THURS NIGHT-FRI MORNING. HIGH PRESSURE OVER THE NE STATES RIDGES SWD OVER THE WATERS FRI NIGHT-SAT AS LOW PRESSURE PUSHES OFF THE NC COAST. STRENGTHENING PRESSURE GRADIENT WILL RESULT IN INCREASING NELY WINDS OVER THE COASTAL WATERS LATE FRI NIGHT THRU SAT. HIGH PRESSURE REMAINS ANCHORED OFF THE NE COAST THRU EARLY NEXT WEEK RESULTING IN PERSISTENT ONSHORE FLOW. ATTM...SPEEDS APPEAR TO REMAIN SUB-SCA...BUT SEAS ARE FORECAST TO BUILD TO 4-5 FT LATE SAT THRU MON.
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&& .AKQ WATCHES/WARNINGS/ADVISORIES... MD...MODERATE RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR MDZ025. NC...MODERATE RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR NCZ102. VA...MODERATE RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR VAZ098>100. MARINE...NONE. && $$ SYNOPSIS...AJZ NEAR TERM...AJZ SHORT TERM...AJZ/ALB LONG TERM...SAM AVIATION...TMG MARINE...SAM

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