Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 280644 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 244 AM EDT THU APR 28 2016 .SYNOPSIS... A COLD FRONT WILL BECOME STALLED FROM SOUTH CENTRAL VIRGINIA TO NORTHEAST NORTH CAROLINA TONIGHT THROUGH FRIDAY. WEAK WAVES OF LOW PRESSURE WILL MOVE EAST ALONG THE STALLED BOUNDARY...BRINGING UNSETTLED CONDITIONS TO THE REGION. && .NEAR TERM /UNTIL 6 AM THIS MORNING/... LATE EVENING ANALYSIS SHOWING THE SFC COLD FRONT HAS NOW PUSHED SOUTH OF THE CWA...WITH E/NE FLOW NOW PREVAILING. WIDESPREAD SHOWERS ONGOING ACRS FAR SRN VA AND NE NC...WITH ANOTHER AREA OF SHOWERS ACRS I-64 CORRIDOR IN CENTRAL VA. HAVE 60-70% POPS IN THESE AREAS...ELSEWHERE POPS ARE 20-40% FOR JUST A FEW LIGHT SHOWERS. THERE IS SOME ELEVATED INSTABILITY AS EVIDENCED BY TSTMS PUSHING THROUGH METRO NORFOLK DESPITE SFC TEMPS IN MID 50S AND ZERO CAPE. NAM12/RAP SHOW A STRIP OF NEGATIVE SHOWALTER INDICES ACRS SE VA THROUGH THE NEXT FEW HRS AND HAVE FOLLOWED THIS FOR KEEPING TSTMS IN PLACE THROUGH THE NEXT 2-3 HRS. JUST SOME BRIEF HEAVY DOWNPOURS/LIGHTNING WITH THIS ACTIVITY AS LOW LEVELS ARE NOW STABLE...EVEN INTO NE NC. PRECIP COVERAGE LOOKS TO DIMINISH AFTER MIDNIGHT...THOUGH WILL KEEP POP NO LOWER THAN 30-50% OVERNIGHT ACROSS THE SOUTH WITH ANOTHER WEAK DISTURBANCE ALOFT LOOKING TO CROSS INTO THE AREA ALONG WITH THE SFC FRONT STALLED ACRS THE AREA. LOOK FOR EARLY MORNING LOWS TO RANGE FROM THE UPPER 40S TO LOW 50S EASTERN SHORE/NORTHERN NECK TO LOWER 60S INTERIOR NE NC AND SOUTH CENTRAL VA. && .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM FRIDAY/... THE FRONT REMAINS STALLED INVOF VA/NC BORDER THROUGH THU NIGHT. MEANWHILE, THE UPPER LOW WILL CONTINUE TO WEAKEN AS IT LIFTS ACROSS THE UPPER GREAT LAKES. 12Z/27 MODELS CONTINUE TO DEPICT A MORE WIDESPREAD AREA OF SHOWERS DEVELOPING IN ASSOCIATION WITH NEXT DISTURBANCE CUTTING ACROSS THE MID-ATLANTIC/NORTHEAST, ALBEIT A BIT LATER INTO THU MORNING. DESPITE PWATS ~1.25" ACROSS THE NORTH, PRESENCE OF WEAK SHORTWAVE RIDGING AND SFC HIGH PRESSURE NUDGING IN FROM THE NORTH SHOULD KEEP AREAL COVERAGE OF SHOWERS LIMITED...AND HAVE ACCORDINGLY DROPPED POPS BACK INTO CHC RANGE THU/THU NIGHT. APPEARS BEST CHANCE FOR THUNDER WILL ONCE AGAIN BE WITH DIURNAL DESTABILIZATON IN THE WARM SECTOR ACROSS SRN VA/NE NC ALONG THE STALLED FRONTAL BOUNDARY. PRIMARY THREATS WILL ONCE AGAIN BE STRONG GUSTY WINDS AND SMALL HAIL. HIGHS THU IN THE 60S NE TO LOWER 70S SW. THE STALLED BOUNDARY WILL REMAIN INVOF SRN VA/NE NC THU NIGHT INTO FRI. PRECIPITATION STARTS TO WANE THU NIGHT AS OVERALL PATTERN BEGINS TO CHANGE WITH LAST WAVE OF LOW PRESSURE EXITING THE COAST WITH A FINAL WAVE DROPPING DOWN FROM THE NW. THIS SECOND WAVE SHOULD BE ENOUGH TO GENERATE WIDELY SCATTERED SHOWERS FRI AFTN DURING PEAK HEATING. AFTER WHICH...DRIER AIR STARTS TO MOVE INTO THE REGION. THERE IS VERY LIMITED FORCING/INSTABILITY PRESENT BY FRI AND THUNDERSTORMS ARE NOT CURRENTLY ANTICIPATED DURING FRI AFTN. HOWEVER...ANY SIGNIFICANT CLEARING SHOULD BE DIFFICULT WITH PERSISTENT ONSHORE WINDS PULLING THE MARINE BOUNDARY LAYER INLAND AND KEEPING THE LOWER ATMOSPHERE GENERALLY SATURATED. LOWS THU NIGHT IN THE 50S INTERIOR VA AND MD/VA EASTERN SHORE...LOWER 60S NE NC. HIGHS FRI WILL BE SIMILAR TO THU WITH TEMPS IN THE 60S NE TO LOWER 70S SW. LOWS FRI NIGHT IN THE LOWER 50S (UPPER 40S POSSIBLE MD LOWER EASTERN SHORE/FAR NRN VA COUNTIES). && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... BLOCKY FLOW PROGGED OVER THE WRN CONUS THRU THE EXTENDED PERIOD (BEGINNING FRIDAY)...WITH A SERIES OF UPPER LEVEL DISTURBANCES PROGGED TO CROSS THE MID ATLANTIC REGION THRU THE WEEKEND. THE FIRST SHORTWAVE DROPS INTO THE NRN MID ATLANTIC REGION FRI AS THE ASSOCIATED AREA OF LOW PRESSURE STALLS OVER THE VICINITY OF WRN PA. ANOTHER AREA OF LOW PRESSURE DEVELOPS OFF THE MID ATLANTIC COAST ALONG THE STALLED FRONTAL BOUNDARY. THE PA LOW IS FORECAST TO DISSIPATE AS THE WAVY FRONT WEST OF THE LOCAL AREA BECOMES DIFFUSE. HIGH PRESSURE RIDGES FROM THE NORTH...RESULTING IN COOL/STABLE CONDITIONS ACROSS THE NE. EXPECT LINGERING CLOUD COVER OVER THE LOCAL AREA...BUT DUE TO DOWNSLOPING EXPECT THE PIEDMONT INTO CENTRAL VA TO REMAIN DRY. BETTER MOISTURE AND FORCING FOR ASCENT ASSOCIATED WITH THE SHORTWAVE EXPECTED OVER THE NRN NECK AND EASTERN SHORE. HAVE TRIMMED BACK CHANCE POPS TO THOSE AREAS FRI AFTERNOON FOR SCATTERED SHOWERS. TEMPS RANGE FROM THE LOW/MID 60S NE TO THE MID/UPPER 70S SOUTH AND SOUTHWEST. SHORTWAVE PUSHES OFFSHORE FRIDAY NIGHT WITH DRYING CONDITIONS EXPECTED. LOWS MID/UPPER 40S NORTH TO LOW/MID 50S SOUTH UNDER A PARTLY CLOUDY SKY. HIGH PRESSURE REMAINS RIDGED OVER THE LOCAL AREA SATURDAY...WITH LIGHT ONSHORE FLOW KEEPING CONDITIONS RELATIVELY COOL AND DRY. SKY AVERAGES PARTLY CLOUDY-MOSTLY CLOUDY. HIGHS GENERALLY IN THE UPPER 60S/LOW 70S (50S ALONG THE IMMEDIATE COAST). THE NEXT SYSTEM APPROACHES THE REGION FROM THE WEST SATURDAY NIGHT. EXPECT PRECIP TO OVERSPREAD THE PIEDMONT LATE SAT NIGHT/EARLY SUN MORNING AND POINTS EWD THRU THE DAY SUNDAY. HAVE INCREASED POPS TO LIKELY SUN AS UPPER LEVEL ENERGY PROVIDES FORCING FOR ASCENT OVER AN INCREASINGLY MOIST (BUT STABLE) AIR MASS. MEDIUM RANGE GUIDANCE AT ODDS WITH PUSHING THE FRONT THRU THE REGION SUN NIGHT AND MONDAY. HAVE LINGERED CHANCE POPS MONDAY DUE TO UNCERTAINTY. STRENGTHENING UPPER LEVEL RIDGE OVER THE WRN CONUS EARLY NEXT WEEK WILL RESULT IN TROUGHING OVER THE NE AND MID ATLANTIC STATES. HOWEVER...GUIDANCE IS AT ODDS OVER HOW THE TROUGH DEVELOPS. POPS RANGE FROM SILENT TO SLIGHT CHANCE DUE TO UNCERTAINTY. HIGHS SUN TO WEDNESDAY GENERALLY IN THE UPPER 60S/LOW 70S. LOWS GENERALLY IN THE 50S. && .AVIATION /07Z THURSDAY THROUGH MONDAY/...
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A STATIONARY FRONT IS SITUATED W-E OVER ERN NC EARLY THIS MORNING. ALL TAF SITES ARE ON THE COOL-SIDE OF THE BOUNDARY...WITH WIDESPREAD IFR STRATUS IN NE FLOW. A SLOW MOVING CLUSTER OF TSTMS LINGERS OVER PORTIONS OF NE NC...BUT THE BEST INSTABILITY IS W OF ECG WITH ONLY -RA OCCURRING THERE. HOWEVER...A FEW LIGHTNING STRIKES REMAIN POSSIBLE NEAR ECG IN THE STRATIFORM REGION OF THE TSTM COMPLEX. IFR CIGS ARE EXPECTED TO CONTINUE THE NEXT SEVERAL HOURS AT ALL SITES...WITH SOME IMPROVEMENT POSSIBLE AT SBY AND ECG LATER THIS MORNING. CURRENT GUIDANCE SUGGESTS RIC/ORF/PHF REMAIN IFR THROUGH THE DAY. A SHORTWAVE TROUGH APPROACHES FROM THE W LATER THIS MORNING AND THIS COULD TRIGGER AREAS OF -RA. ANOTHER WAVE LATER TODAY COULD TRIGGER SOME AFTN SHOWERS/TSTMS. THE FRONT NUDGES NWD TODAY TOWARD THE VA/NC BORDER...BUT THEN SETTLES BACK SWD TONIGHT AS LOW PRESSURE MOVES OFFSHORE. ALL SITES ARE ONCE AGAIN EXPECTED TO HAVE IFR CIGS BY TONIGHT. LOW PRESSURE PULLS WELL OFFSHORE FRIDAY. HOWEVER...LOW-LEVEL MOISTURE LINGERS IN NE FLOW. HIGH PRESSURE BUILDS INTO THE AREA FRIDAY NIGHT INTO SATURDAY. LOW PRESSURE TRACKS ACROSS THE AREA SUNDAY AND SUNDAY NIGHT...WITH A COLD FRONT DROPPING THROUGH THE REGION MONDAY. THIS WILL BRING ANOTHER CHC OF RAIN AND DEGRADED FLIGHT CONDITIONS.
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&& .MARINE... BACKDOOR COLD FRONT HAS PUSHED SOUTH ACROSS THE MARINE AREA THIS AFTN, PRODUCING A WIND SHIFT TO NE. THE FRONT WILL CONTINUE TO SLOWLY DROP SOUTH THIS OVERNIGHT THEN MOVE BACK NORTH TO NEAR THE VA NC BORDER THURSDAY. HAVE DROPPED SCA ACROSS THE NRN COASTAL WATERS, WITH BUOY 09 DROPPING BELOW 5 FT, AND WITH NWPS/WAVEWATCH BOTH DEPICTING SEAS SUBSIDING TO ~4FT THROUGH EARLY EVENING. E-NE WIND 10-15KT CONTINUES TONIGHT THROUGH EARLY THURSDAY, WITH THE FRONT EXPECTED TO REMAIN ALONG/JUST S OF THE VA/NC BORDER THROUGH THURSDAY...WITH A WAVE OF LOW PRESSURE TRACKING ALONG THE BOUNDARY AND MOVING OFFSHORE THURSDAY NIGHT INTO FRIDAY. SUB-SCA CONDITIONS AREA EXPECTED TO PERSIST TONIGHT THROUGH THURSDAY NIGHT WITH AN E-NE WIND ALONG WITH 3-4FT SEAS AND 2-3FT WAVE IN THE BAY. SEAS BEGIN TO BUILD ONCE AGAIN IN INCREASING NE FLOW, WITH ANOTHER ROUND OF SCA NEEDED ACROSS NORTHERN COASTAL WATERS AS EARLY AS LATE THU NIGHT. ONSHORE FLOW PERSISTS FRIDAY AS ANOTHER AREA OF LOW PRESSURE DEVELOPS OFF THE MID ATLANTIC COAST AND HIGH PRESSURE RIDGES IN FROM THE NORTH. N TO NE WINDS INCREASE TO 15 TO 20 KT OVER THE COASTAL WATERS LATE FRIDAY. AOB 15 KT ELSEWHERE. SEAS BUILD TO 4 TO 6 FT. WAVES 2 TO 3. NORTH TO NORTHEAST WINDS OF 10 TO 20 KT CONTINUE SAT AS LOW PRESSURE LIFTS AWAY FROM THE COAST AND HIGH PRESSURE REMAINS. SEAS BUILD TO 5 TO 7 FT LATE FRI NIGHT...WITH 3 TO 4 FT WAVES IN THE MOUTH OF THE BAY. SEAS SUBSIDE TO 4 TO 5 FT LATE SATURDAY. HIGH PRESSURE SLIDES OFFSHORE SAT NIGHT AND SUN AS AN AREA OF LOW PRESSURE APPROACHES FROM THE WEST. ONSHORE FLOW IS EXPECTED TO PERSIST THRU THE WEEKEND...WITH SEAS RANGING FROM 3 TO 4 FT AND 4 TO 5 FT AT TIMES. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...MAM NEAR TERM...LKB/MAM SHORT TERM...BMD/MAM LONG TERM...SAM AVIATION...AJZ MARINE...MAM/SAM/LSA

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