Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 020013 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 813 PM EDT MON JUN 1 2015 .SYNOPSIS... SCATTERED THUNDERSTORMS WILL IMPACT THE AREA THROUGH THIS EVENING AS A SLOW MOVING COLD FRONT APPROACHES FROM THE NORTHWEST. THIS COLD FRONT WILL DROP INTO THE REGION LATE TONIGHT...AND STALL OVER THE AREA TUESDAY INTO WEDNESDAY. HIGH PRESSURE BUILDS ACROSS THE NORTHEAST WEDNESDAY...SLIDING OFFSHORE THURSDAY. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... SCATTERED THUNDERSTORMS HAVE DEVELOPED THIS AFTN AND WILL PERSIST THROUGH THIS EVENING. PULSE-TYPE CONVECTION WITH SOME TRAINING OF MORE ORGANIZED CELL CLUSTERS WILL PRIMARILY RESULT IN PERIODS OF HEAVY RAINFALL...WHICH COULD CAUSE PONDING OF WATER ON ROADWAYS AND IN POOR DRAINAGE/LOW LYING AREAS. THE POTENTIAL ALSO EXISTS FOR WET MICROBURST WIND GUSTS AND SMALL HAIL UNDER STRONGER STORM CORES. PWATS THIS MORNING WERE AROUND 1.50 INCHES (OR AROUND 150 PERCENT OF NORMAL) AND ARE EXPECTED TO INCREASE TWD 1.75 INCHES INTO THIS EVENING. HOWEVER...ATMOSPHERIC SOUNDING PROFILES ARE NOT COMPLETELY SATURATED PLUS THERE IS JUST ENOUGH SOUTHWEST STEERING FLOW ALOFT (ABOUT 15KT) TO ALLOW FOR A NEWD TO EWD DRIFT IN OVERALL MOVEMENT OF STORM CELLS. THIS MOVEMENT SHOULD BE SUFFICIENT ENOUGH TO REDUCE THE POTENTIAL FOR FLASH FLOODING ACROSS THE AREA (1HR FLASH FLOOD GUIDANCE REQUIRES AT LEAST 2.50 TO 3.00 INCHES OF PRECIP OR MORE)...DESPITE ANY TRAINING OF STORMS. A FEW ISOLATED STORMS COULD STILL POP-UP CLOSER TO THE COAST AS THUNDERSTORM OUTFLOW INTERACTS WITH LOCALIZED SEABREEZE BOUNDARIES. CONVECTIVE ACTIVITY IN THE SRN HALF OF THE FA SHOULD DIMINISH BY MID TO LATE EVENING...WITH SHOWERS/STORMS PERSISTING OVER THE NRN HALF OF THE FA OVERNIGHT AS A SFC COLD FRONT SLOWLY SAGS SWD INTO THE REGION. WARM AND MUGGY OVERNIGHT AS TEMPS AND DEWPOINTS ONLY FALL INTO THE UPPER 60S TO AROUND 70. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/... THE SFC COLD FRONT SLOWLY FLATTENS ACROSS THE AREA DURING TUESDAY AS HIGH PRESSURE BUILDS OVER THE ST LAWRENCE RIVER VALLEY. MEANWHILE...PLENTY OF RETURN MOISTURE STREAMS UP INTO THE MID ATLANTIC REGION BTWN AN UPPER RIDGE OVER THE WRN ATLANTIC AND A STALLED CLOSED LOW BACK TO THE WEST OVER THE TN VALLEY/NRN GULF COAST STATES. ALTHOUGH A BRIEF BREAK IN PRECIPITATION IS POSSIBLE TUE MORNING...ESPECIALLY SOUTH AND EAST OF THE COLD FRONT...IT WILL BE SHORT-LIVED AS THE INCOMING MOISTURE INTERACTS WITH THE FRONTAL BOUNDARY...THUS INCREASING THUNDERSTORM CHANCES BY TUE AFTN. ONCE AGAIN... PWATS WILL BE AROUND 1.50-1.75 INCHES WITH STEERING FLOW ALOFT AROUND 20-30KT. ATMOSPHERIC PROFILES START OUT SOMEWHAT DRY BTWN 1000-850MB AND 850-500MB WITH UNIDIRECTIONAL SOUTHWEST WINDS...BUT BECOME SATURATED BY 00Z WED WITH UNIDIRECTIONAL SOUTH WINDS. THIS WILL ENHANCE THE POTENTIAL FOR HEAVY RAINFALL AND TRAINING THUNDERSTORMS. WILL NEED TO SEE RAINFALL TOTALS FROM THIS EVENING TO EVALUATE WHETHER OR NOT A FLASH FLOOD WATCH WILL BE NEEDED FOR TUE AFTN/EVENING. CURRENT 1HR FLASH FLOOD GUIDANCE REQUIRES A MINIMUM OF 2.50 TO 3.00 INCHES. MAIN IMPACTS FROM ANY THUNDERSTORMS CONTINUES TO BE HEAVY RAINFALL...WHICH MAY CAUSE PONDING OF WATER ON ROADWAYS AND IN POOR DRAINAGE/LOW LYING AREAS. ALSO...SMALL HAIL (LESS THAN ONE INCH IN DIAMETER) AND WET MICROBURST WIND GUSTS WILL ONCE AGAIN BE POSSIBLE. EXPECT COOLER HIGH TEMPS ACROSS FAR NWRN COUNTIES (MID-UPPER 70S) AND SLIGHTLY WARMER TEMPS FROM 80-85 FROM RICHMOND METRO SEWD. LOWS TUE NIGHT IN THE UPPER 50S TO LOWER 60S NW TO MID-UPPER 60S SE. HIGH PRESSURE SLIDES DOWN INTO NEW ENGLAND WED AND OFF THE NEW ENGLAND COAST ON THU. THIS WILL CAUSE THE SFC COLD FRONT TO SLOWLY PUSH SWD DURING THIS TIME AND KEEP UNSETTLED CONDITIONS ACROSS THE AREA. PERIODS OF SHOWERS AND THUNDERSTORMS SHOULD BE ANTICIPATED EACH DAY/NIGHT. HEAVY RAINFALL WILL CONTINUE TO BE THE MAIN IMPACT AS STEERING FLOW REMAINS LIGHT AND PWATS HOVER BTWN 1.50-1.75 INCHES. MUCH COOLER WED WITH HIGHS IN THE UPPER 60S TO LOWER 70S NW TO MID-UPPER 70S SE. LOWS WED NIGHT IN THE 60S. HIGHS ON THU REBOUND SLIGHTLY WITH READINGS OF 75-80 DEGREES. ABOUT 5-10 DEGREES COOLER AT THE BEACHES ON WED...AND ONLY AROUND 5 DEGREES COOLER AT THE BEACHES ON THU. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... LONG TERM PERIOD WILL FEATURE UNSETTLED CONDS WITH NR NORMAL TEMPS. A MID-LEVEL CUTOFF LO WILL APPROACH FM THE W ERLY IN THE PERIOD LEADING TO A GOOD CHANCE (50%) OF SHRAS/TSTMS. WILL HOLD ONTO 30-40% POPS INTO THE WEEKEND AS WELL AS MODELS TEND TO BE TOO PROGRESSIVE WITH THESE SYSTMS. THERE IS ALSO CONSIDERABLE UNCERTAINTY REGARDING WHAT HAPPENS AFTER THE CUTOFF LO OPENS UP/WEAKENS...WITH SOME GUIDANCE CONTINUING TO HINT AT CSTL LO DEVELOPMENT LATE IN THE WEEKEND INTO ERLY NEXT WEEK. WILL BE ABLE TO FINE-TUNE THE FORECAST LATE IN THE WEEK BUT FOR NOW WILL FORECAST 30% POPS SUN AND MON. AS FOR TEMPS...EXPECT HIGHS TO AVG IN THE UPR 70S TO LWR 80S EACH DAY...WITH LOWS RUNNING THRU THE 60S. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/...
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A COLD FRONT ACROSS MARYLAND TO SOUTHERN WEST VIRGINIA WILL MOVE SLOWLY SOUTH AND THROUGH THE TAF SITES ON TUESDAY. SHOWERS AND THUNDERSTORMS ACROSS INLAND AND NORTHERN PORTIONS OF THE CWA WILL DISSIPATE LATE IN THE EVENING...AFFECTING RIC AND SBY BEFORE MIDNIGHT. WILL NEED TO WATCH PHF WITH TS NOT FAR TO THE N/W. MOS FORECASTS SUPPORT IFR AT RIC DURING THE EARLY MORNING HOURS AND INCLUDED IN THE TAF FOR NOW BUT CONFIDENCE IS NOT HIGH. AFTER THE COLD FRONT MOVES THROUGH...WINDS TURN TO THE NORTHEAST AND CIGS WILL LIKELY LOWER ESPECIALLY NORTHERN PORTIONS. RAIN AND SCT TSTMS ARE ALSO EXPECTED. FOR NOW HAVE IFR AT SBY AND MVFR AT PHF AND RIC. MOISTURE IS NOT EXPECTED TO BE LOW ENOUGH TO LOWER CIGS BELOW VFR AT ORF AND ECG THROUGH 00Z. OUTLOOK...ONSHORE NE FLOW TUE NIGHT INTO THU AND MOIST AIRMASS SHOULD LEAD TO UNSETTLED/MOSTLY CLOUDY CONDITIONS AND PERIODIC MVFR TO MARGINAL IFR CIGS/VSBYS. SHOWERS AND A FEW THUNDERSTORMS CAN BE EXPECTED WEDNESDAY WITH A CHANCE FOR SHOWERS AND POSSIBLY THUNDERSTORMS THURSDAY THROUGH SUNDAY.
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