Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 200045 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 845 PM EDT SUN APR 19 2015 .SYNOPSIS...
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LOW PRESSURE OVER INDIANA WILL CONTINUE TRACKING NORTH INTO THE GREAT LAKES REGION OVERNIGHT...PUSHING A WARM FRONT THROUGH THE LOCAL AREA. A COLD FRONT THEN CROSSES THE AREA MONDAY NIGHT. HIGH PRESSURE BUILDS BACK IN FROM THE SOUTHWEST ON TUESDAY.
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&& .NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
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CURRENT ANALYSIS SHOWING DEEP SFC LOW ~995 MB OVER CENTRAL INDIANA...WITH HIGH PRESSURE WELL OFF THE SRN NEW ENGLAND COAST. SFC WARM FRONT IS CURRENTLY MOVING IN FROM THE SE AND PUSHING THROUGH NE NC AND WILL PROGRESS INTO SE VA OVER THE NEXT FEW HRS. WIDESPREAD RAIN OVER THE ENTIRE REGION...EXCEPT IN THE MD ERN SHORE...ALTHOUGH RAIN WILL BE MOVING IN THERE SHORTLY. TEMPERATURES IN THE E/NE FLOW NORTH OF THE ADVANCING WARM FRONT HAVE DIPPED INTO THE MID-UPPER 50S OVER MUCH OF CENTRAL/ERN VA..AND DOWN TO 50 F AT OCEAN CITY MD. TEMPERATURES IN FAR SRN VA AND NE NC ARE IN THE 60S. THUS FAR...INSTABILITY AND TSTMS HAVE REMAINED SOUTH OF THE CWA NOW PUSHING INTO SRN/SE PORTIONS OF NC. GIVEN SOMEWHAT OF AN IN-SITU WEDGE PATTERN...EXPECT THIS CONVECTION TO GRADUALLY SHIFT TO THE N/NE OVER THE NEXT FEW HRS...WITH BEST CHANCE FOR TSTMS INTO AKQ CWA NOT ARRIVING FOR AT LEAST A FEW MORE HRS (ABOUT 11 PM AT EARLIEST)...AND PRIMARILY AFFECTING THE FAR SE ZONES. SEVERE WX MOST LIKELY STAYING SOUTH OF THE CWA AS INSTABILITY TENDS TO SHIFT OFF THE ERN NC COAST INTO THE GULF STREAM. RAIN TOTALS SO FAR HAVE AVERAGED FROM ABOUT 0.25" TO 0.50" ACRS CENTRAL AND SRN VA AND NE NC. BEST LIFT/FORCING AND INCREASING LOW LEVEL THETA-E AND PRECIPITABLE WATER VALUES HAVE YET TO ARRIVE...SO A WIDESPREAD ADDITIONAL PRECIPITATION AMOUNTS OF 0.75" TO 1.50" IS ANTICIPATED. HAVE CONTD MENTION OF HEAVY RAIN (ALTHOUGH DELAYED UNTIL AFTER MIDNIGHT ACRS THE NE). PCPN AMTS TO RMN BLO 6-12 HR FLASH FLOOD GUIDANCE SO NO FLASH FLOOD WATCH WILL BE ISSUED. MAJORITY OF THE RAIN SHIFTS TO THE CST BY 12Z/20. THERE WILL ALSO BE GUSTY ESE WINDS TO 20-30 MPH...HIGHEST NR THE CST. ADDED AREAS OF FOG (VSBYS 1-3NM) OVR THE WTRS - AFT MDNGT...DUE TO WARMER AIR SPREADING OVR COOLER WTRS. LOW TEMPS ARE OCCURRING NOW IN MANY AREAS...UPPER 40S TO LOWER 50S MD ERN SHORE...TO THE LOWER-MID 60S IN NE NC...WITH TEMPS STEADY TO SLOWLY RISING OVERNIGHT.
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&& .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... THE AREA OF RAIN WILL SHIFT OFF THE COAST MON MRNG...THEN CONCERN SHIFTS TO A TROUGH ALOFT APPROACHING FROM THE WEST BY LATE MON AFTN/EVE (LIKELY LEADING TO SCT SHWRS/TSTMS). SPC CONTS TO PUT THE AREA OUTLOOKED IN A SLIGHT RISK OF SVR TSTMS MON AFTN/EVE FOR THE POTENTIAL OF ISOLD DAMAGING WIND GUSTS AND LARGE HAIL. THE POTENTIAL FOR SVR WX IS CERTAINLY THERE GIVEN ML CAPE VALUES EXPECTED TO BE IN THE 1000-1500 J/KG RANGE...STEEP LAPSE RATES...AND A MODEST SHEAR PROFILE. WILL CONT TO HIGHLIGHT POSSIBLE STRONG/ISOLD SVR STORMS IN THE HWO FOR LATE MON AFTN/EVE. OTW...VRB CLOUDS-PARTLY SUNNY AND BREEZY/WARMER MIDDAY/AFTN ON MON. HI TEMPS IN THE 70S AT THE CST...80 TO 85 ELSW. COLD FRONT CROSSES THE FA MON NGT WITH CHC POPS...THEN DRYING/COOLER WESTERLY FLOW TAKING OVR INTO TUE. PARTLY/MOSTLY SUNNY TUE WITH HI TEMPS IN THE UPR 60S TO NR 70 AT THE COAST...AND L/M70S ELSW. HI PRES MOVES TO NR THE SE CONUS CST BY WED...PROVIDING WSW FLO AND CONTG MILD WX. A WK TROUGH SFC-ALOFT WILL BE APPROACHING FM THE WNW...WHICH MAY RESULT IN INCRSG CLDNS W AND N...ALG W/ PSBL ISOLD/SCT SHRAS/TSTMS (HWVR WILL CAP POPS AT 14% THOSE AREAS FOR NOW). LO TEMPS TUE NGT M40S W AND N TO FAR L50S SE. HI TEMPS WED IN THE L/M70S N AND NW...TO M/U70S CNTRL/SE. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... BROAD CYCLONIC FLOW PREVAILS THRU THE EXTENDED PERIOD AS UPPER CLOSED LOW REMAINS IN VIC OF THE GREAT LAKES AND NEW ENGLAND. TO BEGIN THE PERIOD...FAST MOVING COLD FRONT CROSSES THE REGION LATE WEDS NIGHT-EARLY THURS MORNING. GFS CONTINUES TO REMAIN ON THE SLOWER SIDE OF MODEL GUIDANCE WRT FRONTAL PASSAGE...WITH THE ECMWF QUICKER. BASED ON WLY FLOW ALOFT AND HIGH PRESSURE BACK OVER THE MIDWEST...OPTED TO REINTRODUCE SLIGHT CHANCE POPS WEDS NIGHT OVER THE NRN AND NERN ZONES AND THEN THURS SOUTH AND EAST OF RICHMOND...TRENDING SLIGHTLY TOWARD THE SLOWER GFS. HIGHS THURS AROUND NORMAL...LOW-MID 60S. THEREAFTER...COOL HIGH PRESSURE BUILDS SWD FROM THE CANADIAN PRAIRIES INTO THE MIDWEST...EXTENDING INTO THE MID-ATLANTIC REGION FRI. HIGHS FRI GENERALLY IN THE UPPER 50S NE TO MID 60S SE UNDER A PARTLY CLOUDY SKY AND NWLY WINDS. SRN STREAM SHORTWAVE PROGGED TO LIFT INTO THE MIDWEST FRI NIGHT-SAT WITH ASSOCIATED SFC LOW FORECAST TO PROGRESS EWD ALONG A STATIONARY BOUNDARY OVER THE GULF STATES SAT. MOISTURE RETURNS SAT TO GO ALONG WITH OVERRUNNING AND WEAK PERTURBATIONS ALOFT. INCREASED POPS TO SLIGHT CHANCE N TO CHANCE S. HIGHS SAT GENERALLY AROUND 60 ACROSS THE REGION. SFC LOW MOVES OFF THE CAROLINA COAST SAT NIGHT...WITH ANY REMAINING PRECIP EXPECTED ACROSS THE SE LOCAL AREA. HIGH PRESSURE RETURNS SUN...BUT COOL CONDITIONS PERSIST WITH HIGHS IN THE UPPER 50S NE TO LOW 60S SE. && .AVIATION /01Z MONDAY THROUGH FRIDAY/...
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WIDESPREAD RAIN HAS DEVELOPED ACROSS THE TAF SITES...JUST STARTING TO GET TO SBY AT 00Z TAF ISSUANCE. IFR CONDS HAVE BEEN INTERMITTENT TO THIS POINT BUT IT APPEARS THAT THEY WILL BECOME MORE PERSISTENT LATER IN THE EVENING. WINDS INCREASE FROM THE SE OVERNIGHT AS A DEEPENING LOW PRESSURE PULLS NE INTO THE GREAT LAKES TIGHTENING THE PRESSURE GRADIENT AHEAD OF A WARM FRONT. WILL ASSESS THE NEED FOR LLWS MENTION IN THE TAFS FOR THE EARLY MORNING HOURS LATER THIS EVENING AND AMEND THE TAFS IF NEEDED. THE WARM FRONT WILL MOVE NE THROUGH THE MID ATLANTIC STATES MONDAY MORNING. THE MAIN PART OF THE RAIN PULLS NE OUT OF THE AREA BETWEEN 10-15Z WITH LOW CLOUDS/LIGHT DRIZZLE CONTINUING INTO THE MID TO LATE MORNING. CONDITIONS IMPROVE TO VFR TOWARD MIDDAY. THUNDERSTORMS WILL LIKELY DEVELOP TOWARD THE END OF THE 00Z TAF PERIOD AND INTO MONDAY EVENING AS A COLD FRONT APPROACHES FROM THE WEST. OUTLOOK...THE COLD FRONT MOVES OFF THE COAST MONDAY NIGHT. AN EXTENDED PERIOD OF MAINLY DRY AND VFR CONDITIONS CAN BE EXPECTED DURING THE UPCOMING WORK WEEK STARTING TUESDAY.
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&& .MARINE... LATEST WX ANALYSIS DEPICTS LOW PRESSURE OVER THE MID MS VALLEY...HIGH PRESSURE OFF THE NE COAST AND A BACKDOOR COLD FRONT LOCATED NEAR THE VA/NC BORDER. GRADIENT HAS RESULTED IN INCREASING ELY WINDS OVER THE WATER THIS AFTERNOON...WITH SCA HEADLINES NOW IN EFFECT FOR ALL WATERS. SPEEDS GENERALLY 15 TO 25 KT. SEAS HAVE BUILT TO 6 FT IN THE NRN WATERS AND 3-4 FT ELSEWHERE. WAVES GENERALLY 2-3 FT. LOW PRESSURE LIFTS INTO THE GREAT LAKES REGION TONIGHT...WITH SECONDARY LOW PRESSURE DEVELOPING OVER THE MID-ATLANTIC REGION. THIS IS A FAVORABLE PATTERN FOR A SHORT DURATION (~3-5 HR) OF STRONG SCA CONDITIONS IN SE FLOW. HI-RES GUIDANCE CONTINUES TO HIGHLIGHT THE MIDNIGHT TO 4-5AM TIMEFRAME FOR THE STRONGEST SE WINDS OF 20-25 KT WITH GUSTS OF 30 KT. BUMPED UP SEAS TO 6-9 FT (HIGHEST IN THE NRN COASTAL WATERS) LATE TONIGHT. FOG ALSO EXPECTED OVER THE WATERS TONIGHT AS WAA OCCURS OVER COOL WATER. GRADIENT WINDS DIMINISH MON MORNING AS FLOW BECOMES SLY 10-15 KT. FAVORABLE FETCH/SWELL WILL KEEP SEAS ELEVATED THRU THE DAY...BUT SUBSIDING TO 4 TO 6 FT. COLD FRONT APPROACHES FROM THE WEST LATE MON...CROSSING THE REGION TUES NIGHT. SLIGHT UPTICK IN SLY WINDS EXPECTED MON EVENING IN ADVANCE OF THE FRONT...AROUND 15 KT IN THE BAY AND 20 KT COASTAL WATERS. SHOWERS/THUNDERSTORMS EXPECTED ALONG THE FRONT...WITH STRONG GUSTY WINDS POSSIBLE. SEAS SUBSIDE LAST MON NIGHT-TUES MORNING THANKS TO WLY WINDS. SCA CONDITIONS NOT EXPECTED BEHIND THE FRONT. HEADLINES HAVE BEEN EXTENDED THRU 7AM TUES FOR COASTAL WATERS SOUTH OF PARRAMORE ISLAND AND THRU 1PM TUES NORTH OF PARRAMORE ISLAND. HIGH PRESSURE BUILDS ACROSS THE SOUTHEAST TUESDAY AND WEDNESDAY AS LOW PRESSURE LINGERS OVER THE GREAT LAKES. A WEAK COLD FRONT CROSSES THE REGION LATE WEDNESDAY NIGHT INTO THURSDAY. HIGH PRESSURE RETURNS INTO THE WEEKEND. && .HYDROLOGY...
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AVG QPF 0.75-1.50"...LOCALLY UP TO 2.00" OVR MOST OF THE RIVER BASINS WILL RESULT IN RIVER LVLS TO PSBLY RISE TO 1/2-NR FULL BANKFULL TUE INTO WED.
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&& .TIDES/COASTAL FLOODING...
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A PERIOD OF ONSHORE FLOW TODAY FOLLOWED BY MODEST SE FLOW TONIGHT WILL ALLOW TIDAL ANOMALIES TO BUILD TO ~1.0FT ABOVE NORMAL LATER TONIGHT PRIMARILY IN THE MIDDLE BAY AND ALONG THE ATLANTIC COAST OF THE MD/VA ERN SHORE. SOUTHERLY FLOW MONDAY INTO MONDAY EVENING WILL HELP MAINTAIN ~1.0 FT ANOMALIES IN THE MIDDLE BAY THROUGH MONDAY NIGHT. TIDAL ANOMALIES WILL BEGIN TO SUBSIDE TUESDAY AS THE FLOW BECOMES OFFSHORE.
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&& .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 10 AM EDT MONDAY FOR ANZ630>638. SMALL CRAFT ADVISORY UNTIL 7 AM EDT TUESDAY FOR ANZ654-656-658. SMALL CRAFT ADVISORY UNTIL 1 PM EDT TUESDAY FOR ANZ650-652. && $$ SYNOPSIS...LKB NEAR TERM...ALB/LKB SHORT TERM...ALB/JDM LONG TERM...SAM AVIATION...LSA MARINE...SAM HYDROLOGY...AKQ TIDES/COASTAL FLOODING...AKQ

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