Area Forecast Discussion
Issued by NWS Wakefield, VA

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000
FXUS61 KAKQ 262059
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
437 PM EDT THU MAR 26 2015

.SYNOPSIS...
A COLD FRONT THAT WILL CROSS THE REGION LATE THIS EVENING AND
OVERNIGHT...EXITING THE COAST BY FRIDAY MORNING. AN UPPER LEVEL
DISTURBANCE WILL PASS THROUGH THE AREA LATER FRIDAY THROUGH
SATURDAY NIGHT. HIGH PRESSURE RETURNS FOR SUNDAY.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
DISSIPATING LIGHT RAIN SHOWERS EXTEND FROM ROUGHLY SALISBURY MD
TO EDENTON NC LATE THIS AFTN. THIS AREA OF SHOWERS WILL CONTINUE
TO DIMINISH AS THEY TRACK NNE OVER THE NEXT FEW HOURS...COMING TO
AN END BY SUNSET. MEANWHILE...AN APPROACHING COLD FRONT EXTENDS
FROM SCNTRL PA THROUGH CNTRL TN AS OF 400 PM AND WILL CROSS THE
REGION LATER THIS EVENING (AFTER 800 PM) AND OVERNIGHT...EXITING
THE COAST BY MORNING. AMPLE CLEARING AND TEMPERATURES WARMING INTO
THE MID 70S THIS AFTN WEST OF INTERSTATE 95 AND ALSO NW OF
RICHMOND SHOULD LEAVE BEHIND JUST ENOUGH INSTABILITY BEHIND INTO
THE EVENING HOURS TO KEEP A SLIGHT CHANCE OF THUNDER IN FAR NWRN
COUNTIES AS THE LEADING EDGE OF PRECIP ARRIVES. OTHERWISE...THE
TIMING OF THE FRONT IS NOT IDEAL TO SUPPORT THUNDER ACROSS THE
REST OF THE AREA OVERNIGHT. A COLDER AIRMASS MOVES IN BEHIND THE
COLD FRONT AND A BRIEF PERIOD OF BREEZY NW WINDS WITH GUSTS UP TO
25 MPH SHOULD BE ANTICIPATED. TEMPERATURES ARE EXPECTED TO FALL
INTO THE LOWER 40S NW TO LOWER 50S SE BY MORNING.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
HIGH PRESSURE STARTS TO BUILD INTO THE MID ATLANTIC REGION FROM
THE NW ON FRI AS A DEEP UPPER LEVEL TROUGH DIGS INTO THE
AREA...CONTINUING TO BRING A MUCH COOLER AIRMASS INTO THE AREA.
HAVE LOWERED HIGH TEMPERATURES INTO THE MID-UPPER 40S BASED ON
THICKNESSES...MODEL TEMPERATURE TRENDS...AND CLOUDY SKIES IN
WIDESPREAD PRECIP (PROMOTING EVAPORATIVE COOLING) AS THE UPPER
TROUGH NOSES INTO THE MID ATLANTIC REGION. THERE WILL BE VERY
LITTLE DIURNAL TEMPERATURE CHANGES OCCURRING ON FRI AS A RESULT.
THERE IS PLENTY OF MOISTURE PRESENT AND INSTABILITY AVAILABLE IN
THE POST-COLD FRONT/UPPER TROUGH ENVIRONMENT TO HOLD ONTO
WIDESPREAD SHOWERS FRI MORNING WHICH WILL BECOME MORE FOCUSED
ALONG THE COAST BY FRI AFTN. MODEL CROSS SECTIONS SHOW MID-LEVELS
OF THE ATMOSPHERE DRYING OUT DURING THE AFTN WHILE SQUEEZING OUT
THE LAST BIT OF MOISTURE AVAILABLE FOR PRECIPITATION
GENERATION/SUSTAINABILITY. THE NAM IS MUCH FASTER THAN THE GFS IN
THIS CASE...HOWEVER THE INCOMING SHORTWAVE ENERGY ASSOCIATED WITH
THE UPPER TROUGH WILL PROVIDE THE BEST LIFT FOR CONTINUED SHOWER
ACTIVITY WITH THE REMNANT MOISTURE AVAILABLE DURING THE AFTN.
SHOWERS REALLY DIMINISH FRI EVENING/OVERNIGHT AND TEMPS DROP INTO
THE LOWER 30S NW (UPPER 20S POSSIBLE FOR FAR NWRN AREAS IN
LOUISA/FLUVANNA COUNTIES) AND THE MID-UPPER 30S SE. PRECIP-TYPE
WILL PRIMARILY BE IN THE FORM OF RAIN FRI NIGHT...HOWEVER SNOW (OR
GRAUPEL) COULD MIX WITH RAIN ON THE WRN FRINGE OF THE PRECIP
SHIELD WHERE THE COLDEST TEMPS WILL OCCUR. LITTLE TO NO
ACCUMULATIONS ARE ANTICIPATED AND IMPACTS TO TRAVEL ARE NOT
EXPECTED.

THE UPPER TROUGH MOVES DIRECTLY OVERHEAD ON SAT/SAT NIGHT AND SO
DO THE COLDEST TEMPERATURES ASSOCIATED WITH THIS AIRMASS. HIGHS
ONLY EXPECTED TO REACH INTO THE MID-UPPER 40S. IF THERE ARE ANY
LINGERING SHOWERS IN THE MORNING...THERE COULD STILL BE A MIX OF
RAIN AND SNOW ON THE WRN EDGES OF PRECIP. AFTN INSTABILITY WITH
THE TROUGH OVERHEAD WILL LIKELY RESULT IN WIDESPREAD CUMULUS WHICH
MAY RESULT IN ISOLATED SHOWERS THAT SHOULD STAY CONFINED ALONG THE
COAST. THERE COULD STILL BE SOME GRAUPEL MIXED WITH RAIN ACROSS
THE NRN NECK AND MD EASTERN SHORE DUE TO THE CONVECTIVE NATURE OF
THE PRECIP. ALL SHOWERS FINALLY COME TO AN END SAT EVENING...SKIES
CLEAR...AND TEMPERATURES PLUMMET INTO THE 20S BY SUN MORNING. SFC
HIGH PRESSURE MOVES ACROSS THE REGION ON SUNDAY. SUNNY SKIES WILL
BE THE MAIN WEATHER HIGHLIGHT BUT THE DRY/STABLE ENVIRONMENT WITH
LIGHT WEST WINDS WILL KEEP TEMPERATURES IN CHECK WITH READINGS
ONLY WARMING INTO THE MID-UPPER 40S ALONG THE IMMEDIATE COAST TO
THE LOWER 50S ACROSS INTERIOR VA AND ALL OF NE NC.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... OVERALL PATTERN WILL
FEATURE SOME FLATTENING OF THE MID LEVEL FLOW IN THE MEDIUM RANGE
WITH A WEAKER VERSION OF A MEAN UPPER RIDGE IN THE WESTERN CONUS AND
AND TROUGH IN THE NE CONUS. WHAT LOOKS TO BE A FAIRLY  WEAK FRONT
WILL PASS THROUGH THE REGION ON MON. LATEST 12Z/26 ECMWF SHOWING A
LITTLE MORE MOISTURE THAN THE GFS AS IT DIGS THE SHORTWAVE FARTHER
SOUTH. WILL HAVE A SLIGHT CHC POP FOR SHOWERS FOR NOW...NO GULF
CONNECTION PRESENT IN WNW FLOW ALOFT SO ANY POTENTIAL QPF AMOUNTS
LOOK FAIRLY LIGHT. TEMPERATURES MON REMAIN SEASONABLE...HIGHS MAINLY
IN THE 60S...A BIT COOLER OVER THE ERN SHORE. NEXT SHORTWAVE SLATED
FOR THE MIDDLE OF THE WEEK WILL REMAIN FARTHER NORTH...MOVING FROM
THE UPPER MIDWEST AT 12Z/TUE...TO OFF THE NEW ENGLAND COAST WED/WED
NIGHT. THIS WILL BRING DRY WX TO THE LOCAL AREA TUE/WED AS LOW LEVEL
FLOW SHIFTS TO THE SSW ON TUE...AND THEN TO THE W ON WED AS SFC LOW
PRESSURE PASSES ACRS THE GREAT LAKES AND NE CONUS. HIGHS MAINLY IN
THE 60S...ALTHOUGH SOME LOWER 70S ARE POSSIBLE WELL INLAND DEPENDING
ON THE PRECISE TRACK OF THE SFC LOW. GFS/ECMWF DIVERGE BY THU...GFS
BEING THE WETER SOLN AS SFC LOW PRESSURE APPROACHES FROM THE TN
VALLEY WITH HIGH PRESSURE OFF THE COAST. WILL HAVE CHC POPS FOR NOW.
TEMPERATURES WILL BE HIGHLY DEPENDENT ON CLOUD COVER...STAYING NEAR
CLIMO AT THIS POINT WITH HIGHS MAINLY IN THE 60S TO AROUND 70 F.
MORNING LOWS MON-THU AVG IN THE UPPER 30S TO UPPER 40S.

&&

.AVIATION /20Z THURSDAY THROUGH TUESDAY/...
THE CURRENT SURFACE ANALYSIS HAS A COLD FRONT EXTENDING FROM LOW
PRESSURE OVER CENTRAL PENNSYLVANIA ACROSS WEST VIRGINIA TO
MISSISSIPPI. A WEAK LOW PRESSURE SYSTEM WAS OVER EASTERN NORTH
CAROLINA. THIS SECOND LOW WAS HELPING TO PRODUCE SHOWERS OVER EASTERN
PORTIONS OF VIRGINIA AND NORTH CAROLINA AND THE MARYLAND EASTERN
SHORE THURSDAY AFTN.

THE LOW OVER NORTH CAROLINA WILL MOVE TO THE NORTHEAST AND PCPN IS
EXPECTED TO END BY LATE AFTN. THE COLD FRONT OVER WEST VIRGINIA WILL
MOVE THROUGH THE TAF SITES EARLY FRIDAY MORNING. RAIN AND MVFR OR
IFR CEILINGS WILL DEVELOP BEHIND THE FRONT AND CONTINUE THROUGH MUCH
OF THE DAY FRIDAY.

OUTLOOK...CONDITIONS SLOWLY IMPROVE LATE FRIDAY/FRIDAY NIGHT FRIDAY
AS THE WIND SHIFTS TO N/NW. ISOLATED RAIN AND SNOW SHOWERS ARE PSBL
SATURDAY. OTHERWISE...MAINLY DRY AND VFR CONDITIONS ARE EXPECTED TO
PREVAIL SATURDAY INTO EARLY NEXT WEEK.

&&

.MARINE...
LOW PRESSURE QUICKLY TRACKS FROM THE UPPER OHIO VALLEY ACROSS PA AND
INTO SRN NEW ENGLAND TODAY. THIS WILL PRODUCE A GENERALLY LOW-END
SCA SSW WIND OF 15-25KT PRIMARILY OVER THE MOUTH OF THE
BAY...OCEAN...AND CURRITUCK SOUND. THE WIND WILL BE STRONGEST OVER
THE OCEAN WITH GUSTS UP TO 30KT POSSIBLE. SEAS ARE EXPECTED TO BUILD
TO 5-7FT OVER THE OCEAN (HIGHEST N)...WITH 3FT WAVES IN THE BAY. A
COLD FRONT TRACKS THROUGH THE REGION TONIGHT. THE WIND WILL ABRUPTLY
TURN TO NNE AT 10-15KT...AND THEN INCREASE TO 20-25KT AS LOW-LEVEL
CAA COMMENCES. AN SCA WAS HOISTED FOR THE BAY/LOWER JAMES FOR THE
POST-FRONTAL SURGE. HOWEVER...CONFIDENCE IS NOT HIGH ENOUGH TO RAISE
THIS SCA FOR THE PRE-FRONTAL WIND TODAY. THE REMAINING FLAGS HAVE
BEEN EXTENDED TO INCLUDE THE POST-FRONTAL WIND AS ANY PERIOD OF SUB-
SCA CONDITIONS APPEARS TO BE ON THE ORDER OF ~6HR. WIND/WAVES/SEAS
SUBSIDE FOR A SHORT PERIOD OF TIME LATER FRIDAY
AFTERNOON/EVENING...BEFORE ANOTHER ROUND OF MARGINAL SCA CONDITIONS
ARE POSSIBLE LATER FRIDAY NIGHT THROUGH SATURDAY NIGHT. HIGH
PRESSURE RETURNS SUNDAY AND MOVES OFFSHORE SUNDAY NIGHT AHEAD OF
ANOTHER COLD FRONT.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 4 AM TO 10 AM EDT FRIDAY FOR
     ANZ635>637.
     SMALL CRAFT ADVISORY UNTIL 4 PM EDT FRIDAY FOR ANZ632>634-650-
     652-654.
     SMALL CRAFT ADVISORY FROM 4 AM TO 1 PM EDT FRIDAY FOR ANZ630-
     631-638.
     SMALL CRAFT ADVISORY UNTIL 7 PM EDT FRIDAY FOR ANZ656-658.

&&

$$
SYNOPSIS...BMD
NEAR TERM...BMD
SHORT TERM...BMD
LONG TERM...ALB
AVIATION...LSA
MARINE...LKB



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