Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 030922 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 422 AM EST TUE MAR 3 2015 .SYNOPSIS...
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HIGH PRESSURE OVER THE AREA THIS MORNING WILL SLIDE OFFSHORE THIS AFTERNOON. A WARM FRONT LIFTS NORTHEAST ACROSS THE REGION TONIGHT... FOLLOWED BY A COLD FRONT SLOWLY CROSSING THE AREA WEDNESDAY AFTERNOON THROUGH WEDNESDAY NIGHT.
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&& .NEAR TERM /THROUGH TONIGHT/...
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1030 MB SFC HIGH PRESSURE IS CENTERED OVER D.C. THIS MORNING. FLOW ALOFT IS FROM THE WNW...WELL OUT AHEAD OF BROAD TROUGHING OVER THE WRN CONUS. MID/HIGH LEVEL CLOUDINESS CONTINUES TO STREAM INTO THE AREA THIS MORNING WHICH HAS IN TURN KEPT TEMPS FROM FALLING OFF TOO SHARPLY. CURRENTLY HAVE UPR 20S/LOW 30S IN PLACE...WITH SOME MID 30S ACROSS SOUTHSIDE HAMPTON ROADS AND NE NC. WITH DRY AIRMASS IN PLACE THIS MORNING AND 00Z GUIDANCE SHOWING LACK OF APPRECIABLE LOW-LEVEL MOISTURE REACHING THE FA UNTIL AFTER 15Z...HAVE LIMITED POTENTIAL FOR ANY PCPN ACROSS THE AREA UNTIL AFTER 18Z...EXPECT SLIGHT CHC POPS (20%) IN THE FAR NW AROUND 15Z. CENTER OF SFC HIGH PRESSURE GRADUALLY PUSHES OFFSHORE BY THIS AFTERNOON...BUT LOW LEVEL CAD REMAINS OVER THE FA. CLOUDS WILL CONTINUE TO THICKEN THRU THE MORNING WHICH WILL LIMIT TEMP RISES. BETTER COVERAGE OF PCPN IS EXPECTED BY MID/LATE AFTERNOON. MODEL SOUNDINGS CONTINUE TO SUPPORT A BRIEF PERIOD OF FZRA OVR FAR NW AREAS BETWEEN 15-20Z AS TEMPS STRUGGLE TO REACH/SURPASS 32F THROUGH EARLY AFTN. CONFIDENCE REMAINS LOW ATTM GIVEN MARGINAL TEMPS AND A WARM DAY YESTERDAY...SO WILL NOT ISSUE A WINTER WX ADVISORY AS IMPACTS WILL BE NEGLIGIBLE. OTHERWISE...P-TYPE TO BE ALL RAIN OVR THE REGION THIS AFTN/EVE. HIGH TEMPS TO BE REACHED LATE IN THE DAY...RANGING FROM THE M/U30S NW-CENTRAL LOCATIONS TO LOW 40S SE.
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&& .SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
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WARM FRONT TO LIFT NE THROUGH THE FA TONIGHT. BEST MOISTURE AND UVM ACRS CNTRL/NRN PORTIONS OF FA...THUS THE HIGHEST POPS...W/ WITH CHC POPS LIMITED TO SRN VA/NE NC. BULK OF THE RA LIFTS TO NRN PORTION BY LT AT NGT. LO TEMPS LIKELY ARND 00Z/04 WITH RISING TEMPS THROUGH THE NIGHT. TEMPS BY 12Z/04 WED RISE INTO THE MID/UPR 40S TO MID 50S SE. FA BECOMES "WARM SECTORED" WED DUE TO SURGE OF A STRONG SSW FLOW. THERE RMN TIMING ISSUES W/ THE APPROACHING CDFNT FM THE NNW...HOWEVER A GFS/ECMWF BLEND LOOKS LIKE A GOOD COMPROMISE. WILL HAVE HIGHEST POPS (40-70%) BY AFTN ACRS NRN TIER OF FA...W/ SLGT CHC TO CHC (20-40%) TO THE S. FOR NOW...LEAVING OUT ANY MENTION OF T ACRS SRN VA/NE NC...SINCE IT APRS MOST OF MOISTURE CONFINED TO W/ AND BEHIND THE FNT. HI TEMPS FM THE U50S/L60S N TO L70S IN FAR SE VA/NE NC. JUST ONE YEAR AGO...MARCH 2ND-3RD...WENT FM 60S TO L70S (THE 2ND) TO A FEW INCHES OF SN (ON THE 3RD). THIS MAY OCCUR AGN THIS WK (WED-THU). FCST CHALLENGES CONT WED NGT THROUGH THU AS CDFNT SETTLES SSE THROUGH THE FA...AND ANOTHER AREA OF ARCTIC SFC HI PRES BUILDS TWD THE MS/OH VLYS. WILL LEAN TWD THE FASTER ARRIVAL OF COLDER SFC AIR FM THE NNW (GFS/ECMWF) BY LT WED NGT AND CONTG ON THU. THE MDLS EACH HINT AT WK SFC LO PRES TRACKING THROUGH NC AS S/W ALOFT (IN FAST SWLY FLO) IS SHEARED AS IT MOVES EWD INTO THE RGN. ALL THIS LEADS TO A TRANSITION (WRT P-TYPE) LT WED/THU. RA...BECOMES MIXED W/ IP-CHANGING TO SN/IP THEN ENDING AS SN FM NNW TO SE ACRS THE FA (LASTLY ACRS NE NC BY MID OR LT AFTN THU). TIMING THOSE TRANSITIONS AT THIS POINT VERY DIFFICULT...THOUGH CURRENTLY EXPECT A LEAST LGT SN ACCUMS FOR AREAS N OF THE NC/VA BORDER BEFORE THE DAY ENDS THU (T-2 INCHES S...1-4 INCHES N (HIGHEST PTNTTLY FM RIC-SBY)). ALONG W/ THE TRANSITION TO WINTRY PCPN...GUSTY NNE WNDS WILL BE PUSHING COLDER AIR INTO THE RGN. LO TEMPS WED NGT FM ARND 30F N TO THE LOW/MID 40S FAR S. TEMPS THU STEADY OR FALLING.
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&& .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... COLD TO BEGIN THE EXTENDED IN WAKE OF THURS COLD FRONT...BUT MODERATING TEMPS THRU THE WEEKEND WILL BRING TEMPS BACK TO NEAR NORMAL EARLY NEXT WEEK. SHORTWAVE PUSHES OFFSHORE THURS NIGHT WITH THE NRN PORTION OF THE FRONT PUSHING WELL OFFSHORE. SRN PORTION PUSHES SWD OVER THE GULF STATES/NRN GULF...STALLING IN WLY FLOW ALOFT. ENDED CHANCE POPS NEAR THE COAST AT MIDNIGHT...WITH DRYING/CLEARING CONDITIONS THEREAFTER. 1030+MB ARCTIC HIGH PRESSURE BUILDS OVER THE REGION FRI...RESULTING IN ANOTHER COLD DAY WITH HIGHS AROUND 20 DEGS BELOW NORMAL. H85 TEMPS BOTTOM OUT AROUND -12C (-2 STD DEV)...WITH THICKNESSES YIELDING TEMPS IN THE LOW-MID 30S. SFC HIGH PUSHES OFFSHORE FRI NIGHT WITH LIGHT RETURN FLOW HELPING MODERATE LOW LEVEL THICKNESSES. TEMPS FORECAST IN THE MID-UPPER TEENS FRI NIGHT UNDER MOSTLY CLEAR SKIES. THEREAFTER...MEDIUM RANGE GUIDANCE BEGINS TO DIVERGE THANKS TO DEVELOPING SPLIT FLOW OVER THE WRN CONUS. THE UPPER PATTERN WILL AGAIN BE CHARACTERIZED BY CYCLONIC FLOW (TROUGHING) OVER THE ERN CONUS AND RIDGING (RETURN TO A +PNA) OVER THE WRN CONUS. MODELS STRUGGLING WITH A NUMBER OF CANADIAN IMPULSES SET TO IMPACT THE NE STATES...BUT ALSO SRN STREAM ENERGY OVER THE BAJA THIS WEEKEND. ECMWF RATHER ROBUST WITH THIS ENERGY...TRANSLATING ACROSS NRN MEXICO AND THE SRN PLAINS SAT NIGHT-SUN...POSSIBLY PHASING WITH NRN STREAM ENERGY OVER THE MIDWEST. THIS SOLUTION WOULD LIFT THE STALLED FRONTAL BOUNDARY OVER THE GULF NWD LATE IN THE WEEKEND...BRINGING RAIN TO THE REGION EARLY NEXT WEEK. THE GFS SHEARS THE ENERGY...KEEPING IT WELL SOUTH OF THE REGION...KEEPING THE LOCAL AREA DRY. HAVE TRENDED FORECAST TOWARD A WPC/ENSEMBLE APPROACH WHICH KEEPS THE SRN STREAM WAVE FLAT AND THE LOCAL AREA DRY THROUGH THE WEEKEND..WITH MODERATING TEMPS. HIGHS SAT FORECAST IN THE UPPER 40S-LOW 50S INLAND AND LOW-MID 40S NEAR THE COAST. HIGHS SUN IN THE MID 50S INLAND AND MID-UPPER 40S NEAR THE COAST. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/...
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SCT-BKN HIGH CLOUDS SHOULD CONTINUE TO PASS OVER THE REGION OVERNIGHT...WITH A LIGHT NNE WIND DUE TO 1030MB HIGH PRESSURE OVER PA. ONE EXCEPTION WILL BE ECG...WHICH WILL HAVE A PERIOD OF 5KFT CIGS OVER THE NEXT FEW HOURS. HIGH PRESSURE MOVES OFFSHORE TODAY...FOLLOWED BY A WARM FRONT TONIGHT. A PERIOD OF -RA IS EXPECTED TO DEVELOP LATER THIS AFTERNOON...PRIMARILY AFTER 21Z. CIGS LOWER TO 4-5KFT THROUGH THE DAY ALONG WITH A LIGHT ESE WIND. THERE IS AN INCREASING POTENTIAL FOR IFR CIGS TONIGHT...ESPECIALLY AFTER 06Z AS THE WARM FRONT LIFTS THROUGH THE REGION. CONDITIONS SHOULD IMPROVE FOR A BRIEF PERIOD LATER WEDNESDAY MORNING. HOWEVER...A COLD FRONT IS EXPECTED TO DROP THROUGH THE REGION DURING THE AFTERNOON FOLLOWED BY DETERIORATING FLIGHT CONDITIONS. THE CHC OF RA INCREASES LATER WEDNESDAY AFTERNOON...WITH RA OVERSPREADING THE ENTIRE REGION WEDNESDAY EVENING. A TRANSITION TO A MIX AND EVENTUALLY SN SHOULD BEGIN AT SBY AFTER 06Z...WITH THE TRANSITION OCCURRING AT RIC CLOSER TO 12Z. FARTHER SE...THE CHANGE SHOULD OCCUR LATER IN THE DAY. ADDITIONALLY...A GUSTY NORTHERLY WIND WILL DEVELOP ALONG THE COAST THURSDAY. HIGH PRESSURE SETTLES OVER THE AREA FRIDAY AND SATURDAY.
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&& .MARINE...
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1030MB SURFACE HIGH PRESSURE SHIFTS OFFSHORE TODAY ALLOWING A 10-15KT NNE WIND TO BECOME SE AOB 10KT BY AFTERNOON. THE HIGH SHIFTS FARTHER OFFSHORE TONIGHT AS A WARM FRONT LIFTS THROUGH THE REGION. DESPITE A STRONG LLJ IT WILL BE DIFFICULT TO OBTAIN SCA CONDITIONS GIVEN WAA OVER COLD WATER. GIVEN THIS...WIND/SEAS HAVE BEEN CAPPED BELOW SCA CRITERIA. OVERALL...EXPECT A SSW WIND ~15KT FOR THE BAY AND A 15-20KT FOR THE OCEAN ALONG WITH 3-4FT SEAS/2-3FT WAVES. A COLD FRONT APPROACHES FROM THE NNW WEDNESDAY MORNING...AND SLOWLY DROPS TO A POSITION NEAR THE VA/NC BORDER BY LATE AFTERNOON/EARLY EVENING. THE FRONT THEN BECOMES NEARLY STATIONARY WEDNESDAY NIGHT AS LOW PRESSURE TRACKS ALONG THE BOUNDARY. CAA COMMENCES THURSDAY AS THE LOW PULLS OFFSHORE AND CONTINUES INTO THURSDAY NIGHT AS 1040MB HIGH PRESSURE BUILDS IN FROM THE NW. SCA CONDITIONS ARE LIKELY DURING THIS TIME PERIOD WITH A NORTHERLY WIND OF 20-25KT...AND 4-7FT SEAS (HIGHEST S) AND 3-4FT WAVES IN THE BAY. HIGH PRESSURE RETURNS FRIDAY AND FRIDAY NIGHT...AND SLIDES OFFSHORE SATURDAY.
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&& .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...JDM NEAR TERM...JDM SHORT TERM...ALB/JDM LONG TERM...SAM AVIATION...AJZ MARINE...AJZ

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