Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 172048 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 448 PM EDT FRI APR 17 2015 .SYNOPSIS... A WEAK TROUGH OF LOW PRESSURE PUSHES ACROSS THE MID ATLANTIC STATES TONIGHT. HIGH PRESSURE BUILDS OVER THE AREA SATURDAY...THEN SHIFTS OFF THE COAST ON SUNDAY. A WARM FRONT LIFTS NORTHEAST SUNDAY NIGHT WITH A COLD FRONT CROSSING THE REGION LATE MONDAY. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... BUMPED POPS TO 40-60% AND ADDED ISOLATED TSTMS TO NW PORTION OF FORECAST AREA THROUGH 00Z...AN AREA OF CONVECTION DEVELOPED NEAR KCHO AND IS NOW PUSHING INTO FLUVANNA/LOUISA COUNTIES. SPC MESOANALYSIS PAGE SHOWING SOME ENHANCED LOW LEVEL CONVERGENCE AND INSTABILITY IN THIS AREA SLOWLY MOVING EAST OVER THE NEXT FEW HRS. NOT EXPECTING SEVERE WX...BUT SOME BRIEF HEAVY DOWNPOURS...SMALL HAIL AND GUSTY WINDS TO 30-40 MPH POSSIBLE. PREV DISC... SKY HAS AT LEAST PARTIAL CLEARED OVR MOST OF THE FA THIS AFTN. INITIAL WK TROUGH ALOFT HAS MOVED OFF THE CST. A SECOND ONE NOW NW OF THE FA (AS EVIDENCED BY BKN-OVC CLDNS AND ISOLD SHRAS) WILL BE APPROACHING THIS EVE...CROSSING THE FA OVRNGT. WILL HAVE VRB CLDS W/ SLGT CHC-LO CHC POPS OVR THE FA. ADDITIONALLY...AN AREA OF MOISTURE WILL BE PASSING BY JUST TO THE S...THOUGH XPCG MOST OF ANY RA FM THAT SYS TO STAY JUST S IN CAROLINAS. CONTG MENTION OF LO CLDS/PATCHY FOG AFT MDNGT GIVEN LINGERING LO LVL MOISTURE AND LGT WNDS. LO TEMPS IN THE 50S. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/... BECOMING A NICE DAY ON SAT (AFT ANY LO CLDS/FOG DISSIPATES). WNW FLOW ALOFT RESULTS IN MSTLY SUNNY CONDS N...PARTLY SUNNY S. AGAIN...THERE MAY BE SCT RA OVR THE CAROLINAS...STAYING S OF THE FA. HI TEMPS M-U70S ALONG THE COAST (XCP NR 70F RIGHT AT THE BEACHES) TO THE U70S-L80S INLAND. SFC HI PRES BUILDS S ACRS THE RGN SAT NGT SHIFTING THE WINDS TO A N-NE DRCTN. DRY/COOLER WITH LO TEMPS IN THE U40S N TO THE L-M50S S. HI PRES SHIFTS OFF THE CST SUN MRNG W/ LO LVL FLO BECOMING ESE. MEANWHILE...LO PRES WILL BE TRACKING TWD THE LWR GREAT LAKES STATES...PUSHING A WARM FRONT NE TWD THE MDATLC RGN. STARTING OUT SUNNY-PARTLY CLOUDY...THEN INCRSG CLDNS XPCD MIDDAY THROUGH THE AFTN (FM W-E). LATEST MDLS GENERALLY HOLDING SERVE WRT TIMING OF ARRIVAL OF ANY RA. RA MAY REACH THE BAY BY EVE...WILL HAVE 30-60% POPS E-W FM THERE. RIGHT AT THE CST...KEEPING POPS AOB 14%. HI TEMPS FM THE U60S/ARND 70F W OF I95 AND RIGHT AT THE BEACHES...TO THE L/M70S ELSW. SIGNIFICANT INFLOW OF DP LYRD MOISTURE INTO THE RGN SUN NGT AS WARM FRONT MAKES PROGRESS NE THROUGH THE FA. MAY BE PDS OF MDT/HVY RA...AND WOULD NOT RULE OUT ISOLD (ELEVATED) THUNDER. THE AREA OF RA XPCD TO SHIFT OFF THE CST MON MRNG...W/ TROUGH ALOFT APPROACHING FM THE W BY LT MON AFTN (PTNTLLY LEADING TO SCT SHRAS/TSTMS). OTRW...VRB CLDS-PARTLY SUNNY MIDDAY/AFTN ON MON. HI TEMPS L/M70S E...U70S-NR 80F W. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... COLD FRONT EXITS THE MID-ATLANTIC COAST TO BEGIN THE EXTENDED PERIOD MONDAY NIGHT AS THE CUT-OFF LOW LIFTS INTO THE GREAT LAKES REGION. WILL MAINTAIN CHANCE POPS (SOLID CHANCE ALONG THE COAST) MON NIGHT...BUT LATEST MODELS HAVE SPED UP FRONTAL PASSAGE. THEREAFTER...BLOCKY FLOW PROGGED TO PREVAIL THRU THE END OF THE PERIOD AS THE UPPER LOW REMAINS OVER THE GREAT LAKES/NEW ENGLAND. SFC HIGH PRESSURE BUILDS ACROSS THE SE STATES/SRN MID-ATLANTIC REGION TUES. WLY/DOWNSLOPE FLOW AND A MOSTLY SUNNY-PARTLY CLOUDY SKY WILL RESULT IN SLIGHT ABOVE NORMAL TEMPS...GENERALLY IN THE LOW 70S INLAND AND MID-UPPER 60S COASTAL AREAS. HIGH PRESSURE PUSHES OFF THE COAST WEDS AS A SHORTWAVE DIVES DOWN THE BACKSIDE OF THE UPPER LOW OVER THE GREAT LAKES REGION. ASSOCIATED COLD FRONT FORECAST TO DROP OVER THE OH VALLEY WEDS. TEMPS WEDS NEAR NORMAL...GENERALLY IN THE MID-UPPER 60S. COLD FRONT CROSSES THE LOCAL AREA LATE WEDS NIGHT- THURS MORNING...BUT PARALLEL FLOW ALOFT WILL STALL THE FRONT OVER THE MID-ATLANTIC REGION. 17/12Z GFS STALLS THE FRONT OVER THE LOCAL AREA WITH MORE MOISTURE THAN ITS 17/12Z ECMWF COUNTERPART...WHICH PUSHES THE FRONT THRU WITH LITTLE FANFARE. HAVE OPTED FOR SLIGHT CHANCE POPS THURS-THURS NIGHT ATTM DUE TO UNCERTAINTY. NEAR NORMAL AGAIN THURS...BEFORE COOLING SLIGHTLY INTO THE LOW-MID 60S INLAND TO MID-UPPER 50S COASTAL AREAS. && .AVIATION /21Z FRIDAY THROUGH WEDNESDAY/... LIGHT DRIZZLE POSSIBLE THROUGH THIS EVENING ACROSS THE SRN HALF OF THE FORECAST AREA AS LOW PRESSURE SLOWLY MOVES FROM THE SOUTHEAST COAST TO THE CAROLINA COAST TONIGHT AND THEN OUT TO SEA ON SATURDAY. MEANWHILE...THERE ARE SLIGHTLY BETTER CHANCES FOR LIGHT RAIN SHOWERS ACROSS THE FAR NRN HALF OF THE FORECAST AREA INVOF A WEAK TROUGH PASSING BY JUST NORTH OF THE REGION. OVERALL CONDITIONS WILL BE CLOUDY TO MOSTLY CLOUDY WITH VFR CIGS/VIS. WHILE FORECAST SOUNDINGS SHOW MOST TAF SITES BECOMING SATURATED AT THE SFC BTWN 18/0600-1200Z...A TECHNIQUE USED IN BUFKIT INDICATES THAT LOW CLOUDS ARE FAVORED OVER FOG. HAVE THEREFORE INTRODUCED SCT LOW CLOUDS AT ALL TAF SITES (EXCEPT KRIC) AFTER 18/0800Z AND KEPT ANY FOG MENTION AT OR ABOVE 4SM. OTHERWISE...HIGH PRESSURE BUILDS INTO THE REGION FROM THE NW-N TONIGHT AND SETTLES ACROSS THE AREA THROUGH THE WEEKEND. VFR CONDITIONS WILL PREVAIL DURING THIS TIME. A WARM FRONT LIFTS THROUGH THE REGION LATE SUN NIGHT INTO MON MORNING...FOLLOWED BY A COLD FRONT CROSSING THE AREA LATE MON NIGHT INTO TUE. THICKENING AND LOWERING CLOUDS STREAMING IN FROM THE SW SHOULD BE ANTICIPATED SUN EVENING. EXPECT STEADY RAIN TO OVERSPREAD THE AREA ALONG THE WARM FRONT SUN NIGHT INTO EARLY MON MORNING AND MORE CONVECTIVE/SHOWERY PRECIPITATION WITH A CHANCE FOR THUNDERSTORMS LATE MON AFTN INTO MON EVENING. PERIODS OF IFR TO MVFR CONDITIONS ARE POSSIBLE SUN NIGHT THROUGH MON EVENING. && .MARINE... LATEST WX ANALYSIS DEPICTS LOW PRESSURE OFF THE SC COAST...HIGH PRESSURE OVER THE OH VALLEY AND A SFC TROUGH OVER THE LOCAL AREA. GRADIENT BTWN THESE FEATURES IS WEAK...WITH SLY WINDS GENERALLY AOB 10 KT OVER THE WATERS THIS AFTERNOON. WAVES AVG 1-2 FT AND SEAS 3-4 FT. FLOW BACKS TO THE NNW TONIGHT AS THE SFC TROUGH CROSSES THE WATERS...REMAINING AOB 10 KT. NNW WINDS PERSIST SAT AS A WEAK BACKDOOR FRONT DROPS SWD OVER THE NRN MID-ATLANTIC REGION. NE FLOW INCREASES LATE SAT NIGHT-SUN MORNING TO 10-20 KT AS THE FRONT DROPS OVER THE WATERS AND HIGH PRESSURE BUILDS OVER THE ST LAWRENCE VALLEY. SPEEDS APPEAR TO REMAIN BELOW SCA CONDITIONS...BUT SEAS PROGGED TO BUILD TO 4-5 FT LATE SUN MORNING-SUN AFTERNOON. HIGH PRESSURE SLIDES OFF THE NE COAST LATE SUN...WITH FLOW BECOMING ELY. LOW PRESSURE LIFTS OVER THE GREAT LAKES REGION LATE SUN-SUN NIGHT. THIS WILL RESULT IN AN UPTICK IN GRADIENT WINDS SUN NIGHT. SCA CONDITIONS ARE EXPECTED WITH GUSTS 20-25 KT IN THE BAY AND 25-30 KT IN THE COASTAL WATERS. SEAS INCREASE TO 5-7 FT. FLOW BECOMES SELY MON AS THE BACKDOOR FRONT LIFTS BACK TO THE NORTH AS A WARM FRONT. WINDS DIMINISH TO 10-15 KT AND SEAS SUBSIDE TO 3-5 FT. COLD FRONT APPROACHES FROM THE WEST LATE MONDAY...CROSSING THE WATERS LATE MON NIGHT. ATTM...SUB-SCA CONDITIONS ARE EXPECTED POST FRONTAL TUES. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...ALB/MPR NEAR TERM...LKB/ALB SHORT TERM...ALB LONG TERM...SAM AVIATION...BMD MARINE...SAM

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