Area Forecast Discussion
Issued by NWS Wakefield, VA

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000 FXUS61 KAKQ 310051 AFDAKQ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WAKEFIELD VA 851 PM EDT SUN AUG 30 2015 .SYNOPSIS... LOW PRESSURE PUSHES ACROSS THE AREA LATE TONIGHT THROUGH MONDAY NIGHT. HIGH PRESSURE BUILDS BACK ACROSS THE SOUTHEAST AND MID ATLANTIC STATES FOR THE MIDWEEK PERIOD. && .NEAR TERM /THROUGH MONDAY/...
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SATELLITE IMAGERY TONIGHT SHOWS THE UPPER LEVEL LOW OVER NERN GA AND THE ASSOCIATED MOISTURE PLUME ALONG THE COAST SENDING CLOUDS NORTHWARD ACROSS THE CWA. AT THIS POINT...THE MOISTURE IS STILL IN THE HIGHER LEVEL OF THE ATMOSPHERE AND EARLIER SPRINKLES THAT MOVED THROUGH THE AREA HAVE BECOME LESS NUMEROUS OVER THE LAST FEW HOURS. OVERNIGHT TONIGHT...THE UPPER LOW WILL BEGIN TO OPEN UP AS THE UPPER TROUGH LIFTS NORTHEASTWARD. THE COASTAL FRONT AND MOISTURE WILL CONTINUE TO LIFT NORTHWARD WITH CEILINGS GRADUALLY LOWERING. AS THE FORCING WITH THE TROUGH SLIDES THROUGH MONDAY MORNING...EXPECT TO SEE SHOWERS...NOW DOWN OVER SC/SRN NC...SPREAD INTO THE REGION...MAINLY NE NC AND THE VA TIDEWATER. SO HAVE INCREASED POPS TO LOW LIKELY VALUES...BUT EXPECT QPF TO BE LOW...MAINLY LESS THAN 0.25". BY MONDAY AFTERNOON...THE TROUGH AXIS SHOULD BE PAST THE REGION AND THE CHANCE FOR RAIN SHOULD BEGIN TO DIMINISH AS MOISTURE AXIS PUSHES BACK OFF THE COAST. PREV DISCUSSION... MID-AFTERNOON SFC ANALYSIS REVEALS ~1020 MB SFC HIGH PRESSURE IN PLACE ACROSS THE LOWER MID-ATLANTIC INTO THE CAROLINAS. LATEST IR/WV SATELLITE IMAGERY CONTINUES TO SHOW AREAS OF MID/HIGH CLOUDS STREAMING NNE ACROSS THE CAROLINAS AND EASTERN TN VLY TOWARD OUR REGION...AS WEAKENING UPPER LEVEL LOW LIFTS NORTH FROM THE GULF COAST INTO THE SOUTHEAST CONUS. REGIONAL RADAR MOSAIC SHOWING SHOWERS AS FAR NORTH AS COASTAL SC...AND EXPECT THESE SHOWERS TO CONTINUE TO SLOWLY LIFT NORTH THIS EVENING. DESPITE ONLY WEAK OVERRUNNING/MINIMAL ISENTROPIC LIFT AND DRY AIR IN LOW LEVELS, MID/UPPER DYNAMICS COULD BE ENOUGH TO GENERATE SOME SCATTERED SHOWERS LATE TONIGHT. HAVE ADJUSTED POP TIMING TO BE MAINLY AROUND AND AFTER MIDNIGHT, WITH MAJORITY OF 30% POP ORIENTED ACROSS THE NE NC COASTAL PLAIN. FORECAST SOUNDINGS INDICATE LOW LEVELS MOISTEN UP ENOUGH THAT AS THIS MOISTURE PUSHES ACROSS, A PASSING SHOWER OR TWO ARE ALSO POSSIBLE ACROSS HAMPTON ROADS AND SOUTH CENTRAL VA LATE TONIGHT. HV THEREFORE GONE WITH A SLIGHT CHANCE MENTION OVER THESE AREAS. OVERALL, PARTLY CLOUDY CONDITIONS TONIGHT WILL BECOME MOSTLY CLOUDY TO OVERCAST AND MILDER OVERNIGHT, WITH EARLY MORNING LOWS GENERALLY 65 TO 70.
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&& .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... MONDAY/MONDAY NIGHT... LINGERING 20-30% RAIN CHANCES CONTINUE FOR ALL BUT MD EASTERN SHORE AREAS FROM MONDAY MORNING INTO THE AFTN. ACCOUNTED FOR A LITTLE BIT OF A LULL IN THE LATE MORNING/EARLY AFTERNOON HOURS AS FIRST SLUG OF LIGHT OVERRUNNING PCPN PUSHES OFFSHORE/ HOWEVER, WITH SW FLOW BRINGING A GRADUAL INCREASE IN PW VALUES MON/MON NIGHT...ANOTHER ROUND OF SHOWERS IS EXPECTED AS LOW LEVEL LIFT/ADDITIONAL UPPER SUPPORT ARRIVES COINCIDENT WITH DIURNAL HEATING. MOVED POPS A BIT FARTHER INTO THE NIGHT MONDAY NIGHT WITH TIMING SLOWING SLIGHTLY. A BIT MORE MUGGY MON W/ HIGHS MON MAINLY IN THE UPPER 80S TO AROUND 90F. BY ALL INDICATIONS, SFC FRONT LOCATES FROM NEAR HATTERAS TO JUST OFF THE FL/GA COAST...AND THUS EXPECT ANY ISSUES WITH HEAVY RAINFALL TO REMAIN CONFINED TO OUR SOUTH. HOWEVER, WITH AN INFLUX OF TROPICAL MOISTURE FROM THE REMNANTS OF ERIKA, BRIEF HEAVY DOWNPOURS WILL BE POSSIBLE ACROSS SE COASTAL PLAIN. TUESDAY/WEDNESDAY... WEAK SFC HIGH PRESSURE WILL REMAIN IN PLACE ACROSS THE REGION, WITH SHOWERS DIMINISHING TO BEGIN THE PERIOD TUESDAY MORNING. THE SOUTHEAST (SUBTROPICAL) RIDGE BUILDS BACK WEST ACROSS THE SE COAST ON TUESDAY, AS WEAK TROUGHING TAKING SHAPE FROM THE WESTERN GULF COAST TO THE OZARKS. MODELS EVENTUALLY CLOSE THIS WAVE OFF BY WEDNESDAY MORNING...AND THIS IN TANDEM WITH THE ANTECEDENT MOIST AIRMASS AND UPPER RIDGE ALOFT WILL BRING INCREASING HEAT AND HUMIDITY FOR THE MIDWEEK PERIOD. THE GOOD NEWS IS THAT FORCING FOR ANY LATE DAY SHOWERS/STORMS IS WEAK AND MAINLY TO OUR SOUTH...AND THUS POPS REMAIN LOW BOTH DAYS. WILL CARRY A 20% POP ACRS THE FAR S/SE FOR ISOLATED AFTN/EARLY EVENING SHOWERS/TSTMS EACH DAY. EXPECT HIGHS TUE IN THE UPPER 80S TO LOWER 90S...AND AROUND 90/LOWER 90S FOR MOST ON WEDNESDAY. EARLY MORNING LOWS EACH DAY UPPER 60S TO LOW 70S. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... THE LONGWAVE PATTERN NEXT WEEK IS EXPECTED TO BE CHARACTERIZED BY BROAD MID/UPPER RIDGING FROM THE N-CENTRAL TO NERN US...WITH A WEAK TROUGH IN VICINITY OF THE GULF COAST. BROAD ESE FLOW BENEATH THE RIDGE IS EXPECTED TO BRING INCREASING TROPICAL MOISTURE INTO THE SERN US. THE BULK OF THIS MOISTURE IS EXPECTED TO BE FROM TS ERIKA...OR ITS REMNANTS AT THAT TIME. THE GENERAL MODEL CONSENSUS SHOWS THE MID-LEVEL ANTICYCLONE CENTERED FROM THE OHIO VALLEY TO MID-ATLANTIC THROUGH AT LEAST WEDNESDAY...WHICH SHOULD KEEP MOISTURE SUPPRESSED S OF THE REGION. IF THE MID-LEVEL HIGH CENTER RETREATS FAR ENOUGH N SOME OF THIS MOISTURE COULD SPREAD INTO THE AREA LATER IN THE WEEK. HOWEVER...IF THE HIGH REMAINS OVERHEAD MOISTURE SHOULD REMAIN S OF THE REGION. WEAK COLD FRONT AND UPPER TROUGH PASS THROUGH THE MID-ATLANTIC ON THURS BUT THIS LOOKS TO HAVE LITTLE AFFECT ON THE CURRENT WEATHER PATTERN. WARM AND INCREASINGLY HUMID THROUGH THE WEEK WITH FORECAST HIGHS IN THE UPPER 80S TO LOW 90S WITH MID-UPPER 80S AT THE IMMEDIATE COAST. BY THURSDAY/FRIDAY FORECAST HIGHS DROP INTO THE MID/UPPER 80S...WITH LOW 80S AT THE BEACHES. FORECAST LOWS ARE IN THE UPPER 60S TO LOW 70S. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... WEAK HIGH PRESSURE WILL CONTINUE TO DOMINATE THE WEATHER DURING THE 00Z TAF PERIOD. AN UPPER LEVEL LOW OVER THE GULF COAST STATES WAS HELPING TO TRIGGER SCATTERED PCPN OVER THE CAROLINAS. THE UPPER LOW WILL MOVE NORTHEAST AND SHEAR OUT ON MONDAY. EARLY SUNDAY EVENING...RADAR AND SATELLITE AS WELL AS SURFACE OBSERVATIONS INDICATED LAYERED CLOUDINESS ABOVE 10K FT OVER THE TAF SITES. THE COLUMN WAS RELATIVELY DRY BELOW THAT. NAM BUFR SOUNDINGS INDICATE A LOWERING OF THE MOIST AIR TO AROUND 5-8K FT OVER SRN PORTIONS OF THE AREA. LIFT WILL BE WEAK BUT SUFFICIENT TO PRODUCE A CHC TO LIKELIHOOD OF LIGHT RAIN AT ORF AND ECG BY MONDAY MORNING. KEPT VSBY AT 7 PLUS AS THERE ARE DOUBTS THAT THE SURFACE WILL GET CLOSE TO SATURATION BUT DID INCLUDE MVFR CIGS AT ECG. THE REST OF THE TAF SITES COULD GET A FEW SPRINKLES DURING THE TAF PERIOD BUT NOT ENOUGH TO MENTION FOR THE TAFS. WINDS WILL REMAIN AOB 10 KNOTS AND GENERALLY FROM A SOUTHERLY COMPONENT. OUTLOOK...HIGH PRESSURE WILL CONTINUE TO DOMINATE WITH A FEW PERIODS OF SLGT TO LOW CHANCES FOR RAIN. MOST OF THE PERIOD THROUGH FRIDAY WILL BE DRY. SOME LIMITED CIGS/VSBY...MAINLY NO LOWER THAN MVFR... MAY OCCUR DURING THE EARLY MORNING HOURS. && .MARINE... HIGH PRESSURE REMAINS OVER THE LOCAL WATERS. THE RESULT IS A LIGHT ONSHORE FLOW (SE TO E) AOB 10 KT. SEAS 2 FT IN THE NORTH AND 2-3 FT SOUTH. WAVES ACROSS THE BAY 1-2 FT. A SLIGHT STRENGTHENING OF THE GRADIENT TONIGHT WILL PUSH SPEEDS TO 10-15 KT. AN EXTENDED PERIOD OF SUB-SCA CONDITIONS IS EXPECTED THRU MID WEEK AS HIGH PRESSURE PREVAILS OVER THE WATER. WIND DIRECTIONS GENERALLY SW TO W THRU WEDS...AOB 15 KT. A BACKDOOR COLD FRONT WILL ATTEMPT TO DROP INTO THE REGION LATE IN THE WEEK. SEAS AVERAGE 2-3 FT AND WAVES 1-2 FT. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...NONE. NC...NONE. VA...NONE. MARINE...NONE. && $$ SYNOPSIS...MAM NEAR TERM...ESS/MAM SHORT TERM...LKB/MAM LONG TERM...AJZ/DAP AVIATION...LSA MARINE...SAM/DAP

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