Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 231821 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 221 PM EDT WED APR 23 2014 .SYNOPSIS... A COLD FRONT WILL CROSS THE REGION EARLY THIS MORNING. COOL CANADIAN HIGH PRESSURE BUILDS BACK OVER THE REGION TONIGHT AND THURSDAY. A SERIES OF WEAK FRONTS WILL CROSS THE AREA FRIDAY INTO THE WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... BASE OF THE UPPER TROUGH HAS LOCATED OVER THE LOCAL AREA PER LATEST WATER VAPOR IMAGERY. AT THE SFC...COLD FRONT HAS PUSHED WELL OFFSHORE AS MODIFYING CANADIAN HIGH PRESSURE HAS CENTERED OVER THE GREAT LAKES REGION. THE RESULT WILL BE A DRY...BREEZY AND COOL DAY OVER THE LOCAL AREA. FOR TODAY...SFC LOW WILL PUSH OFF THE NEW ENGLAND COAST TODAY AS HIGH PRESSURE BUILDS SOUTH AND EAST. PRESSURE GRADIENT WILL REMAIN RATHER STRONG OVER THE REGION...RESULTING IN SUSTAINED NW WINDS OF 15 TO 20 MPH WITH GUSTS UP TO 30 MPH. STRONGER WINDS NEAR THE BAY AND OVER THE ERN SHORE WITH SPEEDS 20 TO 25 MPH AND GUSTS TO 35 MPH. COMBINATION OF BREEZY CONDITIONS AND LOW RH WILL RESULT IN A CRITICAL FIRE WEATHER DAY. PLEASE REFER TO THE FIRE WEATHER SECTION BELOW FOR MORE INFORMATION. REMNANT MID-LEVEL MOISTURE AND GOOD MIXING/STEEP LOW LEVEL LAPSE RATES WILL RESULT IN SOME AFTERNOON CU...ESPECIALLY OVER THE NRN LOCAL AREA AND ERN SHORE WHERE DOWNSLOPE FLOW WILL HAVE LESS OF AN IMPACT. NW FLOW...CAA WILL RESULT IN TEMPS WARMING INTO THE MID-UPPER 60S...EVEN ALONG THE COASTAL WATERS THANKS TO NW WINDS. THE EXCEPTION WILL BE THE ERN SHORE WHERE TEMPS ONLY EXPECTED TO WARM INTO THE LOW 60S. HIGH PRESSURE BUILDS INTO THE REGION TONIGHT. EXPECT CHILLY EARLY MORNING LOWS THU MORNING IN THE MID-UPPER 30S ALONG/W OF I-95 TO THE UPPER 30S TO LOWER 40S ELSEWHERE UNDER CLEAR SKIES. DO NOT EXPECT ANY FREEZE ISSUES AND PROBABLY TOO DRY FOR MUCH MORE THAN SOME PATCHY FROST IN SHELTERED LOCALES. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... DRY AGAIN ONCE AGAIN THU AS HIGH PRESSURE SLIDES OVER THE NORTHEAST/MID-ATLANTIC REGION, BEFORE SLIDING OFF THE ATLANTIC SEABOARD ERY FRIDAY. HIGHS THURS GENERALLY IN THE UPPER 60S (A LITTLE COOLER NEAR THE COAST). ONCE AGAIN, MIN RH VALUES FALL INTO THE 20S THU AFTN BUT WINDS WILL BE LIGHTER. NEXT FAST MOVING WAVE OF MOISTURE MOVES IN FROM THE PLAINS ON FRI. GFS REMAINS FASTER WITH BRINGING SYSTEM THROUGH, WITH THE NAM/ECMWF A BIT SHARPER WITH THE UPPER WAVE...AND HENCE A BIT SLOWER. PUSHED BACK ONSET OF POP JUST SLIGHTLY AND CONTINUED TO SPLIT THE DIFFERENCE BETWEEN THESE STILL DIVERGENT SOLUTIONS. GIVEN THIS, EXPECT A SCENARIO NOT UNLIKE THAT OF EARLIER YESTERDAY (TUESDAY); RATHER MEAGER INSTABILITY WITH MODEST DEEP LAYER SHEAR/LAPSE RATES THAT RESULT IN SOME WEAK DISORGANIZED CONVECTION LATE IN THE DAY FRIDAY. WILL KEEP CHC POPS ALL ZONES FOR SCT SHRAS AND PERHAPS A THUNDERSTORM PUSHING THROUGH AT SOME POINT IN THE AFTN/EVENING. WARMER SSW FLOW SHOULD PUSH HIGHS WELL INTO THE 70S TO NEAR 8O. CLEARING BEHIND THE FRONT FRIDAY NIGHT, WITH POPS QUICKLY ENDING WEST TO EAST. LOWS GENERALLY IN THE 50S TO NEAR 60 ALONG AREA COASTLINES. && .LONG TERM /SATURDAY THROUGH TUESDAY/... PROGRESSIVE FLOW WILL BEGIN TO EVOLVE INTO A HIGHLY AMPLIFIED/BLOCKY PATTERN OVER THE CONUS DURING THE EXTENDED...LIKELY RESULTING IN A COOL/WET PERIOD BY EARLY NEXT WEEK. MEDIUM RANGE GUIDANCE TENDS TO STRUGGLE WITH BLOCKY FLOW...AND THIS IS NO EXCEPTION. TRENDED TOWARD ENSEMBLE AND WPC GUIDANCE TO SMOOTH OUT DIFFERENCES IN THE MODELS. OVERALL...UPPER PATTERN WILL BE CHARACTERIZED BY AN ANOMALOUS UPPER TROUGH OVER THE WRN CONUS...HIGH PRESSURE RIDGING FROM THE GULF STATES INTO THE NORTHWEST TERRITORIES AND ANOTHER UPPER TROUGH OVER SE CANADA AND NEW ENGLAND. WHILE MEANINGFUL DIFFERENCES EXIST IN THE MODELS...A SECOND (DRY) COLD FRONT IS PROGGED TO CROSS THE LOCAL AREA ON SAT. THIS FRONT WILL BRING COOLER/DRIER AIR TO THE REGION ON SUN. A STATIONARY BOUNDARY WILL THEN SET UP OVER THE MID-ATLANTIC REGION (DEPENDING ON THE MODEL IT COULD BE FROM THE CAROLINAS NWD TO THE MASON DIXON LINE). THIS BOUNDARY WILL BE THE FOCUS OF PRECIP EARLY NEXT WEEK. MEANWHILE...A BROAD AREA OF LOW PRESSURE OVER THE PLAINS WILL PROGRESS EWD SUN-TUES...TAPPING INTO GULF MOISTURE. WILL MAINTAIN SLIGHT CHANCE POPS SUN NIGHT-TUES BASED ON UNCERTAINTY...BUT INCREASE TO LOW-END CHANCE POPS TUES NIGHT AS THE UPPER/SFC LOW GETS CLOSER. HAVE TRENDED TO THE COOLER SIDE OF GUIDANCE WITH HIGHS GENERALLY IN THE MID-UPPER 60S SUN-TUES. OVERNIGHT LOWS GENERALLY IN THE UPPER 40S-LOW 50S. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
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AS THE FRONT CONTINUES TO PUSH FARTHER OFF SHORE...THE PRESSURE GRADIENT WILL TIGHTEN UP NEAR THE IMMEDIATE COAST WHERE WNW-NW WINDS SHOULD AVERAGE CLOSE TO 20G30KT BEFORE TAPERING OFF DURING THE EVENING AND OVERNIGHT HOURS. NW WIND SPEEDS BRIEFLY INCREASE THU MORNING AND THEN DROP OFF THROUGH THE AFTN AS HIGH PRESSURE SLIDES ACROSS THE AREA AND BECOMES LOCATED OFF THE SOUTHEAST COAST BY THU EVENING. THE NEXT COLD FRONT APPROACHES THE REGION THU NIGHT...CAUSING NW WINDS TO BACK AROUND TO THE S-SE. THE FRONT IS EXPECTED TO CROSS THE MID ATLANTIC REGION FRI EVENING...BRINGING SHOWERS AND A SLIGHT CHANCE FOR THUNDERSTORMS TO AREA TAF SITES. BEHIND THIS FRONT...WINDS WILL GENERALLY BE NLY AROUND 15 KT OR LESS THROUGH THE REST OF THE WEEKEND.
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