Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 031821 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 121 PM EST TUE MAR 3 2015 .SYNOPSIS... HIGH PRESSURE 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. && .NEAR TERM /THROUGH TONIGHT/... LATE THIS MORNG...HI PRES WAS CNTRD RIGHT ALONG THE CST. FLOW ALOFT IS GENERALLY FM THE W...WELL OUT AHEAD OF BROAD TROF OVER THE WRN CONUS. TEMPS WERE SLOWLY CLIMBING THRU THE 30S TO NEAR 40 DEGREES OVR THE AKQ CWA...WITH DWPTS RANGING FM THE MID TEENS TO THE UPR 20S. RDR SHOWED ONLY VRY LGT MIXED PCPN OR RAIN OVR THE MTNS OF WEST VA AND SW VA. CNTR OF HI PRES WILL PUSH OFFSHR THIS AFTN...BUT LOW LEVEL CAD REMAINS OVER THE FA. A CLOUDY SKY WILL LIMIT TEMP RISES THIS AFTN...WITH HIGHS ONLY RANGING FM THE MID 30S EXTRM NW TO THE MID 40S OVR NE NC. BETTER COVERAGE OF PCPN IS EXPECTED MID/LATE AFTN...WITH BEST PCPN CHCS (50-60%) FOR MAINLY LGT RAIN ACRS NRN AND WRN AREAS. MODEL SOUNDINGS CONTINUE TO SUPPORT A BRIEF PERIOD OF -FZRA OVR FAR NW AREAS BETWEEN 16-20Z AS TEMPS STRUGGLE TO REACH/SURPASS 32F THRU EARLY THIS AFTN. CONFIDENCE REMAINS LOW ATTM GIVEN MARGINAL TEMPS AND A WARM DAY YESTERDAY. OTHERWISE...P-TYPE TO BE ALL RAIN OVR THE REGION THIS AFTN/EVENG. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY/... 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. && .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 /18Z TUESDAY THROUGH SUNDAY/... AN OVERCAST DECK AROUND 3500-5000 FT AGL PERSISTS THIS AFTN AS LIGHT NE WINDS START TO BECOME MORE ELY. A WARM FRONT LIFTS NORTH THROUGH THE AREA TONIGHT. A PERIOD OF -SHRA ARE EXPECTED TO DEVELOP AFTER 03/2100Z ACROSS MOST OF THE REGION...WITH MORE STEADY RAINFALL ACROSS THE NRN NECK AND MD/VA EASTERN SHORE. IFR CIGS OF 500-1000 FT AGL ARE EXPECTED TO DEVELOP AS PRECIP BEGINS AND THEN PERSISTING THROUGH THE OVERNIGHT HOURS. THERE SHOULD BE A BRIEF PERIOD OF IMPROVING CONDITIONS WITHIN THE WARM SECTOR WED MORNING...ESPECIALLY OVER SE VA/NE NC WHERE THE CIGS MAY BREAK UP NICELY. HOWEVER...A COLD FRONT IS EXPECTED TO DROP THROUGH THE REGION WED AFTERNOON FOLLOWED BY DETERIORATING FLIGHT CONDITIONS. THE CHANCE OF RAIN INCREASES LATER WEDNESDAY AFTERNOON...WITH RAIN OVERSPREADING THE ENTIRE REGION WEDNESDAY EVENING. MODELS ARE TRENDING WARMER SLIGHTLY LONGER WHICH SHOULD RESULT IN A TRANSITION TO A WINTRY MIX WITH SLEET FROM NW TO SE AS THU PROGRESSES AND EVENTUALLY TO ALL SNOW BY LATE THU AFTN/EARLY EVENING. ADDITIONALLY...A GUSTY NORTHERLY WIND WILL DEVELOP ALONG THE COAST THURSDAY. HIGH PRESSURE SETTLES OVER THE AREA FRIDAY AND SATURDAY. && .MARINE... 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. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...JDM NEAR TERM...JDM/TMG SHORT TERM...ALB/JDM LONG TERM...SAM AVIATION...AJZ MARINE...AJZ/BMD

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