Area Forecast Discussion
Issued by NWS Wakefield, VA

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000
FXUS61 KAKQ 060610
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
210 AM EDT WED MAY 6 2015

.SYNOPSIS...
HIGH PRESSURE WILL REMAIN WELL OFF THE SOUTHEAST AND MID ATLANTIC
COAST THROUGH TONIGHT...BRINGING VERY WARM AND MAINLY DRY
CONDITIONS TO THE LOCAL AREA. A BACKDOOR COLD FRONT APPROACHES
FROM THE NORTH TONIGHT...THEN DROPS INTO VIRGINIA LATE WEDNESDAY
INTO EARLY THURSDAY...BEFORE DISSIPATING. LOW PRESSURE WILL SPIN
OFF OR NEAR THE SOUTHEAST COAST THURSDAY INTO SATURDAY.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
FORECAST UPDATED TO BOOST POPS ACROSS AREAS NEAR AND N OF RIC
WHERE SHRAS/TSTMS HAVE BEEN WIDESPREAD THIS EVENG. NOT EXPECTING
ANYTHING SVR BUT PERIODS OF HEAVY RAIN ARE PSBL WITH AN OCCASIONAL
LIGHTING STRIKE. COVERAGE WILL DECREASE AFTR MIDNITE.

PREVIOUS DISCUSSION...
LATEST ANALYSIS REVEALS SFC HIGH PRESSURE CENTERED WELL OFFSHORE
OF THE VA/NC COAST, EXTENDING BACK ACROSS EASTERN NC. ~1006 MB LOW
PRESSURE WAS ANALYZED ACROSS NEWFOUNDLAND, WITH SFC COLD FRONT
SNAKING BACK ACROSS NEW ENGLAND INTO NE PA/NW NJ AND THE EASTERN
GRT LAKES. A PRE-FRONTAL SFC TROUGH EXTENDS SW FROM SE PA INTO SRN
MD AND NORTHERN VA.

HAVE NOTED SOME INCREASING CU OVER THE PAST FEW HOURS ALONG THE
BLUE RIDGE AND EXPECT TO SEE A BIT MORE TO DEVELOP ACROSS WESTERN
SECTIONS OF THE LOCAL AREA ALONG THE TROUGH BY OVER THE NEXT FEW
HOURS. DO HAVE SOME LOW CHANCES FOR SHOWERS/TSTMS ACRS THE FAR
N/NW LATE THIS AFTN/EVENING. EXPECT ANY SHOWERS TO BE SHORT LIVED
OWING TO FLAT/QUASI-ZONAL FLOW ALOFT AND SHOULD THEREFORE ALLOW
LIMITED CONVECTIVE DEVELOPMENT AND WILL YIELD A VERY SLOW
SOUTHWARD PROGRESSION OF THE FRONT THROUGH TONIGHT AND INTO
TOMORROW.

BY TONIGHT, SHORTWAVE ENERGY NOTED ON IR SAT ACRS THE LWR GRT
LAKES WILL DAMPEN AS IT DIVES SOUTHEAST ACROSS THE NORTHERN MID-
ATLANTIC. RESULTANT UPPER FLOW SHIFTS TO THE WNW, AND WOULD ALLOW
ANY LINGERING SHOWERS AND STORMS TO CROSS A BIT FARTHER TO THE
SOUTH. GIVEN THE LIMITED ACTIVITY THUS FAR, AND W/ HRRR NOT OVERLY
EXCITED ABOUT ACTIVITY TONIGHT, WILL HANG ON TO A 30-40% RAIN
CHANCE FOR SOME SCT SHRAS THIS EVENING ACROSS THE WEST, AND LATE
TONIGHT/OVERNIGHT FOR THE EASTERN SHORE. FARTHER S-SE, EXPECT DRY
CONDS TO CONTINUE UNDER A PARTLY CLOUDY SKY. LOWS TONIGHT IN THE
UPPER 50S TO LWR 60S.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY/...
HAVE LINGERED A SLIGHT CHC FOR LINGERING SHOWERS JUST AFTER SUNSET
TOMORROW MORNING...W/AREA OF WEAK LIFT SLIDING ESE ALONG AND AHEAD
OF THE BACKDOOR FRONT COINCIDENT WITH PLENTY OF LINGERING LLVL
MOISTURE. ANY SHOWERS WOULD BE BRIEF AND WIDELY SCT AT MOST.
OTHERWISE...DRY IN THE MORNING FOR MOST. EARLY SUN WILL GIVE WAY TO
INCREASING AFTN CLOUDS ACROSS CENTRAL/SOUTHERN ZONES. STRONG HEATING
AND THE ARRIVAL OF THE FRONT WILL LIKELY PROVIDE THE TRIGGER FOR
SOME SCT AFTN SHRAS/THUNDERSTORMS...MAINLY OVR WRN AND NRN COUNTIES
LATE IN THE AFTN INTO WED NIGHT. FOR TEMPS, STILL ON THE WARM SIDE
OF THE GUIDANCE ENVELOPE IN EXPECTATION OF A SLOWER FRONTAL
PROGRESSION...RESULTING IN A PARTLY TO MOSTLY SUNNY SKY EARLY AND
HIGHS FM 80-85 WEST OF THE BAY...TO THE 70S ON THE ERN SHORE. FRONT
BECOMES VERY DIFFUSE TOMORROW NIGHT AND WASHES OUT BY THE TIME IT
REACHES THE VA/NC BORDER. MEANWHILE, SFC LOW PRES WILL BEGIN TO TAKE
SHAPE AND CLOSE OFF ALONG THE EAST COAST OF FLORIDA/SE GA WED
AFTN/NIGHT. WEAK SFC RIDGING WILL RE-ESTABLISH ITSELF OVERHEAD AND
ALLOW FOR A DRY OVERNIGHT WED NIGHT INTO THU MORNING. HOWEVER,
EXPECT A GOOD AMOUNT OF LOW TO MID LEVEL CLOUD TO LINGER OVERNIGHT
INTO THU MORNING ALONG AND BEHIND THE FRONT ACROSS NORTHERN HALF OF
THE AREA. GENERALLY PARTLY SUNNY FARTHER SOUTH A 20-30% CHC FOR A
SHOWER OR TSTM, AGAIN MAINLY IN THE AFTN/EARLY EVENING. E-NE WINDS
WILL RESULT IN HI TEMPS RANGING THRU THE 70S TO NEAR 80 SW TO THE
UPPER 60S/LWR 70S ERN SHORE.

STILL MONITORING THE PROGRESS OF AFOREMENTIONED LOW ALONG THE SE
COAST. MODELS STILL HAVING TROUBLE RESOLVING THIS SYSTEM...WHICH IS
CASTING A BIT OF LOWER CONFIDENCE ON THE HANDLING OF THIS SYSTEM.
THE 12Z/5 GFS CONTINUES TO BRING THE SFC LOW INLAND OF THE SC/NC
COAST...WITH THE 12Z/NAM NOW IN CLOSE ENOUGH TO COVER THU NIGHT AND
FRIDAY. ITS SOLUTION IS SLIGHTLY FASTER THAN THE GFS AND TAKES THE
SURFACE LOW INLAND ACROSS EXTREME NE GA/COASTAL SC BY EARLY FRIDAY
MORNING. FOR ITS PART, THE OPERATIONAL ECMWF REMAINS OFFSHORE, BUT
HAS TRENDED TOWARD THE GFS IN MOVING A BIT CLOSER TO THE COAST WITH
THE SFC LOW...AND EVEN KEEPS THE LOW NEARLY STATIONARY ALONG THE
CAROLINA COAST FOR FRIDAY AND THROUGH THE WEEKEND. HAVE GONE WITH A
GFS WEIGHTED GFS/ECMWF BLEND FOR FRIDAY UNTIL MODELS COME INTO A BIT
CLOSER AGREEMENT. EITHER WAY, EXPECT FRIDAY TO BE PREDOMINATELY
DRY ACROSS THE LOCAL AREA, BUT SHOULD SEE SOME (MAINLY) DIURNALLY
DRIVEN SCT SHOWERS/TSTMS POSSIBLE OVER THE SOUTHERN HALF OF THE
AREA (BEST CHC SOUTH OF THE BORDER INTO NC). HIGHS 80-85 INLAND,
COOLER U60S TO M70S ALONG THE COAST IN CONTINUED ONSHORE FLOW.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
THE EXTENDED PERIOD WILL BEGIN WITH LO PRES SPINNING JUST OFF OR
ALNG THE SE OR NC CST FRI NGT INTO MON MORNG. THEN...MODELS SHOW
THE LO WEAKENING AND GETTING PUSHED NNE ALNG OR JUST OFF THE VA
CST MON NGT INTO TUE MORNG...AS A COLD FRONT APPROACHES FM THE W.
THAT FRONT WILL THEN MOVE ACRS THE AREA TUE INTO TUE NGT. WILL
HAVE 20%-30% POPS FOR SHOWERS OR TSTMS OVR MUCH OF THE REGION FRI
NGT THRU MON NGT...DUE TO MOISTURE/LIFT FM THE LO PRES AREA.
THEN...HAVE 30%-40% POPS FOR TUE/TUE NGT ASSOCIATED WITH THE COLD
FRONT. TEMPS WILL BE ABV NORMAL THRU THE PERIOD...WITH HIGHS
RANGING FM THE MID 70S TO MID 80S. LOWS WILL RANGE FM THE UPR 50S
TO MID 60S.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
EARLIER SHOWERS HAVE DISSIPATED OVER THE REGION...WITH ONLY SOME
LINGERING MID LEVEL CLOUDS AOA 12K FT AGL ACROSS THE LOCAL AREA.
WEAK BACKDOOR FRONT HAS LOCATED OVER SRN PA/OH EARLY THIS MORNING.
HIGH CLOUDS AOA 25K FT AGL ASSOCIATED WITH A SUBTROPICAL LOW OFF
THE FL PANHANDLE HAVE LIFTED OVER SE VA/NE NC. OTHERWISE...SSW
WINDS AOB 10 KT. FOG IS EXPECTED TO DEVELOP OVER THE PIEDMONT INTO
NRN VA WHERE RAINFALL OCCURRED AND SKIES HAVE CLEARED.
HOWEVER...SUFFICIENT DEWPOINT DEPRESSIONS AND CLOUD COVER WILL
PREVENT FOG FROM DEVELOPING AT THE TAF SITES.

WEAK BACKDOOR FRONT DROPS INTO THE REGION THIS
AFTERNOON...PROVIDING THE FOCUS FOR ISOLATED TO WIDELY SCATTERED
AFTERNOON AND EARLY EVENING SHOWERS AND THUNDERSTORMS. BEST
COVERAGE EXPECTED TO BE ACROSS THE PIEDMONT INTO NRN VA AND THE MD
ERN SHORE. DRY SE VA/NE NC. HAVE OPTED TO WAIT TO MENTION IN TAFS
UNTIL CONFIDENCE IS HIGHER. WINDS REMAIN AOB 10 KT THIS
MORNING...BECOMING ONSHORE THIS AFTERNOON. SEA BREEZE BOUNDARIES
POSSIBLE ACROSS THE SE...WITH SPEEDS INCREASING TO AROUND 10 KT.
SKIES RANGE FROM SCT-BKN WITH DECKS 4-6K FT AGL IN THE NORTH TO
SKC IN THE SE.

THE BACKDOOR FRONT WASHES OUT OVER THE AREA TONIGHT AS HIGH
PRESSURE BUILDS IN FROM THE NORTH. DRY CONDITIONS ARE EXPECTED
THURS. LOW PRESSURE LINGERS OFF THE SE COAST THRU THE
WEEKEND...BRINGING CHANCES FOR SHOWERS AND THUNDERSTORMS TO SE
VA/NE NC FRI THRU SUN.

&&

.MARINE...
NO HEADLINES IN THE SHORT TERM TNGT THRU THU. HI PRES WILL SLIDE
FARTHER OUT TO SEA TNGT THRU WED. MODELS STILL SHOW LO PRES
SPINNING JUST OFF OR NEAR THE SE CST THU INTO SUN. EXPECT SSW
WINDS 15 KT OR LESS TNGT INTO WED NGT...THEN E OR SE WINDS 5 TO 15
KT THU INTO SUN. WAVES WILL BE 1 TO 2 FT...AND SEAS WILL BE 2 TO 4
FT.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...MAM
NEAR TERM...MAS/MAM
SHORT TERM...LKB/MAM
LONG TERM...TMG
AVIATION...SAM
MARINE...TMG



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