Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 122005 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 405 PM EDT SAT APR 12 2014 .SYNOPSIS... HIGH PRESSURE BUILDS OFF THE MID ATLANTIC COAST TONIGHT INTO SUNDAY...AND REMAINS ANCHORED OFF THE COAST THROUGH MONDAY. A SLOW MOVING COLD FRONT APPROACHES FROM THE WEST MONDAY NIGHT AND TUESDAY. && .NEAR TERM /THROUGH SUNDAY/...
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LATEST WX ANALYSIS SHOWING A RATHER DIFFUSE FRONTAL BOUNDARY EXTENDING NR/JUST SOUTH OF THE VA/NC BORDER EXTENDING SOUTH INTO NORTH CENTRAL NORTH CAROLINA...AS A ~1025MB SFC HIGH HAS BECOME CENTERED ALONG THE MID-ATLANTIC/SOUTHEAST COAST. ALOFT, WEAK SHORTWAVE RIDGING WAS NOTED BUILDING FROM THE SOUTHEAST TOWARDS THE MID-ATLANTIC REGION. MID-AFTERNOON WV IMAGERY SHOWS A WEAK DISTURBANCE PUSHING ACROSS THE CENTRAL APPALACHIANS THIS AFTERNOON, WHICH HAS ALLOWED SOME SCT CU TO POP UP ACROSS THE PIEDMONT. OLD SURFACE BOUNDARY IS DIFFICULT TO DISCERN ANYMORE, APART FROM A BROAD WIND FIELD SHIFT JUST SOUTH OF THE LOCAL AREA. SURFACE HIGH PRESSURE STRENGTHENS OFF THE MID ATLANTIC COAST TONIGHT INTO SUNDAY, IN RESPONSE TO A BUILDING MID/UPPER RIDGE OVER THE WESTERN ATLANTIC. ACCORDINGLY, WINDS ACROSS THE REGION WILL SHIFT TO THE S-SE THIS EVENING, VEERING AROUND TO THE SW LATE TONIGHT. THIS SHOULD ALLOW AN INCREASE IN LOW LEVEL MOISTURE AND SOME PATCHY STRATUS DEVELOPING OVERNIGHT, WHICH WILL BRING MILD EARLY MORNING LOWS SUNDAY. IT WILL ALSO SERVE TO BOOST HIGHS SUNDAY BACK INTO THE UPPER 70S/LOW 80S AWAY FROM THE COASTLINES. ANY MORNING STRATUS WILL GIVE WAY TO A MOSTLY SUNNY SKY BY SUNDAY MORNING. HIGHS SUNDAY WILL BE LOCALLY COOLER ALONG THE COASTS...ESPECIALLY THE ATLANTIC COAST OF THE EASTERN SHORE WHERE MAXIMA MAY ONLY HOLD IN THE LOW/MID 60S.
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&& .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
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NO MAJOR CHANGE IN FORECAST RATIONALE FOR THE FIRST HALF OF THE WEEK AHEAD. OVERALL, A DEEP UPPER LEVEL TROUGH WILL PUSH A STRONG COLD FRONT THROUGH THE OHIO VALLEY MONDAY/MONDAY NIGHT, WITH A SECOND TRAILING SHORTWAVE PUSHING FROM THE TEXARKANA REGION ACROSS THE SOUTHEAST TUESDAY THROUGH TUESDAY NIGHT. FORECAST REMAINS DRY SUNDAY NIGHT THROUGH MONDAY NIGHT, AS THERE IS PLENTY OF MID- LEVEL DRY AIR ASSOCIATED WITH THE WESTERN ATLANTIC RIDGE. INCREASE TO HIGH LIKELY TO CATEGORICAL POPS (70-80%) LATE MONDAY NIGHT/EARLY TUESDAY MORNING ACROSS THE PIEDMONT/CENTRAL VA ZONES AS FRONT APPROACHES FROM THE WEST. RAIN WILL LIKELY BEGIN AS SOME LIGHTER SHRAS AS SHALLOW LIFT ENSUES AHEAD OF THE FRONT MONDAY NIGHT...WITH MORE STEADY RAINFALL EXPECTED AFTER MIDNIGHT INTO TUESDAY MORNING, AS PW VALUES QUICKLY RAMP UP THROUGH TUESDAY AS MID- UPPER TROUGH TAPS INTO GULF MOISTURE. DELAYED RAMPING UP POPS ACROSS THE EAST AS FORCING REMAINS MEAGER AT BEST UNTIL TUESDAY THROUGH TUESDAY NIGHT. REGARDING THUNDERSTORM CHANCES...DID RETAIN SOME THUNDER WORDING ON TUESDAY AFTN/EVENING AS FRONT PUSHES ACROSS THE AREA AND LOW PRESSURE SLIDES ALONG THE BOUNDARY. MODELED CAPE VALUES ARE MEAGER AT BEST, WHICH MAKES SENSE GIVEN CONSIDERABLE CLOUD COVER. HOWEVER, WITH CONSIDERABLE DEEP LYR BULK SHEAR AND THE POTENTIAL FOR A FORCED LINE OF CONVECTION, SOME THUNDERSTORMS ARE POSSIBLE, ESPECIALLY ACROSS THE SOUTHERN HALF OF THE AREA. OVERALL THOUGH, PRIMARY THREAT WILL JUST BE WITH A BRIEF WINDOW OF MODERATE TO HEAVY RAINFALL TUESDAY AND TUESDAY NIGHT. FOR TEMPERATURES...HIGHS MONDAY SHOULD BE IN THE MID/UPPER 70S (LOCALLY COOLER ALONG THE COASTS) UNDER A PARTLY SUNNY SKY. INCREASING CLOUDS AND MILD SW FLOW WILL KEEP LOWS IN THE LOWER TO MIDDLE 60S MONDAY NIGHT...WITH HIGHS IN THE 60S WEST TO LOW 70S EAST ON TUESDAY.
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&& .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
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LONG TERM PERIOD STARTS OFF TUE NGT WITH AFOREMENTIONED LO PRES AND ASSOCIATED COLD FRONT PUSHING OFFSHORE. 12Z ECMWF HAS COME IN LINE WITH THE 12Z GFS WITH ENDING THE PRECIP OVR THE AREA BY WED MORN. WILL RETAIN CHANCE POPS FOR WED HOWEVER WITH THIS STILL SEVERAL DAYS OUT AND STILL SOME UNCERTAINTY WITH HOW FAST THIS SYSTEM MOVES OFFSHORE. DRYING CONDITIONS WILL FOLLOW...WITH A PROLONGED PERIOD OF PARTLY/MOSTLY CLOUDY SKIES AND ONSHORE FLOW AS SFC HI PRES STRADDLES THE MID ATLANTIC CST. AS FOR TEMPS...READINGS WILL AVG BLO NORMAL FOR THE PERIOD...WITH HIGHS IN THE 50S AND 60S. TEMPS TUE NGT AND WED NGT WILL FALL INTO THE MID/UPR 30S OVR THE PIEDMONT...BRINGING THE POTENTIAL FOR FROST THERE.
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&& .AVIATION /19Z SATURDAY THROUGH THURSDAY/...
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VFR CONDITIONS WILL PREVAIL THROUGH THE TAF PERIOD WITH ONLY A FEW SCATTERED CLOUDS EXPECTED. HIGH PRESSURE MOVES OVER THE REGION AND OFF THE MID ATLANTIC COAST TONIGHT. WINDS WILL GRADUALLY SHIFT FROM NE-SE-S THRU THE PERIOD. THE FRONT THAT MOVED THRU EARLY THIS MORNING WILL RETURN AS A WARM FRONT TONIGHT. SOME PATCHY FOG AND STRATUS WILL BE PSBL OVERNIGHT AS THE FRONT MOVES NORTH BUT IS NOT EXPECTED TO BE WIDESPREAD. A COLD FRONT APPROACHES THE REGION ON MONDAY. THE FRONT WILL BRING WIDESPREAD PRECIP TO THE REGION MON NIGHT INTO WED.
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&& .MARINE...
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BENIGN MARINE CONDITIONS TNGT AS A WEAK FRONT WASHES OUT SOUTH OF THE AREA AND SFC HI PRES ANCHORS OFFSHORE. THE HI WILL REMAIN IN PLACE FOR THE NEXT COUPLE DAYS LEADING TO CONTINUOUS SLY FLOW. EXPECT 5-10 KT WINDS TNGT WITH 1-2 FT WAVES OVR THE BAY AND 2-3 FT SEAS OVR CSTL WTRS. FOR SUN...WINDS OVR THE BAY WILL INCREASE TO 15 KT IN THE AFTN...POSSIBLY UP NEAR 20 KT IN THE LATE AFTN AND EVENING...WITH SEAS OVR NRN CSTL WTRS POSSIBLY REACHING 4-5 FT AS WELL. CONFIDENCE AT THIS POINT IS NOT HI ENOUGH TO ISSUE A LATE 2ND/3RD PERIOD SCA. SCA CONDITIONS ARE MORE LIKELY LATE MON THRU AT LEAST THE MIDDLE OF THE WEEK AS A COLD FRONT APPROACHES THE WTRS AND CROSSES BY TUE EVENING. PROLONGED NE FLOW THEREAFTER WILL KEEP SEAS ELEVATED AOA 5 FT THRU THE END OF THE WEEK.
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&& .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...MAM NEAR TERM...MAM SHORT TERM...AJZ/MAM LONG TERM...LKB AVIATION...JEF MARINE...SAM

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