Area Forecast Discussion
Issued by NWS Wakefield, VA

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000
FXUS61 KAKQ 272327
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
727 PM EDT FRI MAR 27 2015

.SYNOPSIS...
A TROF OF LOW PRESSURE PUSHES ACROSS THE AREA THROUGH SATURDAY
MORNING. HIGH PRESSURE RETURNS SATURDAY AFTERNOON THROUGH SUNDAY.
A WEAK COLD FRONT WILL MOVE ACROSS THE REGION SUNDAY NIGHT INTO
EARLY MONDAY...WITH HIGH PRESSURE RETURNING MONDAY AFTERNOON.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
LOW PRESURE OFF THE CAROLINA COAST IS IS SLOWLY MOVING EAST THIS
EVENING. THE STEADIEST AND HEAVIEST PCPN WITH THE LOW HAS SHIFTED
EAST WITH ONLY AREAS OF LIGHT RAIN BEING REPORTED. TEMPS STILL
ABOVE FREEZING SO KEPT CHC RAIN ALL AREAS WITH THE HIGHEST POPS
ALONG THE COAST THRU MIDNIGHT.

ECHOES ASSCTD WITH THE UVM FROM APPRCHG TROF ALRDY DVLPNG ACROSS
NWRN MOST CNTYS. LATEST RAP/HRRR SHOW THIS PCPN TO CONTINUE THRU
THE OVERNIGHT HOURS AS IT SLOWLY PUSHES ESE ACROSS THE FA. CAA
CONTS AND TMPS WILL EVENTUALLY COOL ENUF TO WHERE THE LGHT RAIN
BECOMES MIXED WITH OR CHANGES TO SNOW SHWRS/FLRYS AFTR 06Z. THE
CHANGEOVER OCCURS OVR THE PIEDMONT FIRST THEN TOWARDS THE CHES BAY
AND COASTAL AREAS AFTR 09Z. ANY QFP AFTR MIDNIGHT WILL BE LIGHT SO
NO IMPACT ISSUES ARE EXPECTED LATE TONIGHT. LOWS NR 30F NW TO
THE M/U30S SE.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
THE UPR TROUGH MOVES DIRECTLY OVERHEAD ON SAT...THEN OFFSHORE BY
SUN MRNG. HIGHS ON SAT ARE ONLY EXPECTED TO REACH INTO THE M/U40S.
IF THERE ARE ANY LINGERING SHWRS IN THE MORNING...THERE COULD
STILL BE A MIX OF RAIN AND SNOW. AFTN INSTABILITY W/ THE TROUGH
OVERHEAD WILL LIKELY RESULT IN WIDESPREAD CUMULUS WHICH MAY RESULT
IN ISOLATED SHWRS THAT SHOULD STAY CONFINED ALONG THE COAST. ALL
SHWRS FINALLY COME TO AN END EARLY SAT EVE...THE SKY CLRS...AND
TEMPS PLUMMET INTO THE 20S BY SUN MRNG.

SFC HIGH PRES MOVES ACRS THE RGN ON SUN. XPCG SUNNY/DRY/COOL WX
W/ LGT WINDS. LIMITED MIXING WILL KEEP TEMPERATURES IN CHECK WITH
READINGS ONLY RISING INTO THE M/U40S ALONG THE CST TO THE L/M50S
ACRS INTERIOR VA AND NE NC.

NEXT TROUGH ALOFT AND ACCOMPANYING SFC CDFNT TO CROSS THE RGN LT
SUN NGT/MON MRNG...W/ VRB CLDS AND LO PROB FOR PCPN (15-30%).
XPCG MORE OF A DP LYRD WSW LO LVL FLO ON MON LEADING TO BETTER
WARMING. SKY AVGG OUT PSNY ON MON...W/ HI TEMPS FM THE L/M60S
E...TO THE L70S W.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
SPLIT FLOW PATTERN PREVAILS THRU THE EXTENDED...AS NRN STREAM
EXPECTED TO REMAIN ACTIVE. THE FIRST NRN STREAM SHORTWAVE EXITS THE
COAST LATE MON NIGHT...WITH ANOTHER SHORTWAVE REACHING THE OH VALLEY
LATE TUES. ASSOCIATED LOW PRESSURE EXPECTED TO LIFT ACROSS NEW
ENGLAND TUES AS HIGH PRESSURE BUILDS ACROSS THE SE STATES.
HOWEVER...THERE IS A GREAT DEAL OF UNCERTAINTY WITH THE EXACT TRACK
OF THE NRN STREAM LOW...WITH THE 27/12Z GFS LIFTING IT THRU NE...THE
27/12Z ECMWF THRU THE NRN MID-ATLANTIC REGION AND THE 27/12Z CMC
THRU NC. BASED ON THE OVERALL PROGRESSIVE PATTERN AND UPPER LEVEL
FLOW...PREFER THE NRN TRACK...KEEPING THE FA DRY. ASSOCIATED WEAK
COLD FRONT PUSHES ACROSS THE REGION TUES NIGHT-WEDS. LIMITED
MOISTURE AND LITTLE APPRECIABLE FORCING WILL RESULT IN A DRY FRONTAL
PASSAGE. UPPER/SFC HIGH PRESSURE BUILDS OVER THE ERN CONUS WEDS.
THEREAFTER...MODELS DIVERGE WITH THE HANDLING OF A SRN STREAM SYSTEM
LIFTING FROM THE SRN PLAINS INTO THE GULF STATES WEDS-WEDS NIGHT.
GFS QUICKER TO RETURN MOISTURE TO THE REGION AS HIGH PRESSURE
LOCATES OFF THE SE COAST WEDS-WEDS NIGHT...WHILE ITS ECMWF AND CMC
COUNTERPARTS ARE SLOWER WITH THE MOISTURE RETURN. THEREAFTER...THE
NEXT NRN STREAM SYSTEM PROGGED TO REACH THE GREAT LAKES/OH VALLEY
LATE THIS WEEK INTO EARLY NEXT WEEKEND. SIGNIFICANT SPATIAL AND
TIMING DIFFERENCES EXIST...WITH THE GFS PUSHING THE FRONT THRU 18
HRS BEFORE THE ECMWF (FRI VS. SAT MORNING). WILL MAINTAIN LOW END
CHANCE POPS BEGINNING THURS. WILL CARRY LOW END CHANCE POPS THROUGH
FRI...BUT AGAIN CONFIDENCE IS NOT HIGH ATTM.

TEMPS TO BEGIN THE EXTENDED WILL BE RIGHT AROUND SEASONABLE
NORMS...IN THE 60S INLAND AND UPPER 50S-LOW 60S ERN SHORE AND
COASTAL AREAS. THURS HIGHS WILL BE DEPENDENT ON POTENTIAL CLOUD
COVER/PRECIP. HAVE OPTED FOR A BLEND...RESULTING IN HIGHS IN THE
UPPER 60S TO NEAR 70 INLAND AND LOW-MID 60S ERN SHORE AND COASTAL
AREAS. LOWS GENERALLY IN THE LOW-MID 40S.

&&

.AVIATION /23Z FRIDAY THROUGH WEDNESDAY/...
A COLD FRONT NEAR THE CAROLINA COAST SOUTH OF CAPE HATTERAS HAS A
LOW PRESSURE SYSTEM THAT WILL MOVE TO THE NORTHEAST OUT TO SEA
THIS AFTN. A DEEP UPPER LEVEL TROUGH WILL APPROACH THE MID
ATLANTIC STATES FROM THE WEST SATURDAY MORNING. HIGH PRESSURE
BUILDS INTO THE REGION SATURDAY NIGHT AND SUNDAY.

CONDITIONS AT THE TAF SITES HAVE FREQUENTLY VARIED FROM VFR TO IFR
WITH MVFR BEING THE MOST PREDOMINANT CONDITION EXCEPT MOSTLY IFR AT
ECG. IT HAS BEEN DIFFICULT TO NAIL DOWN THE TRENDS BUT BUFR
SOUNDINGS WOULD INDICATE AN OVERALL DECREASE IN LOW LEVEL MOISTURE
TOWARD EVENING. THE SOUNDINGS BECOME MORE SATURATED AGAIN WITH THE
APPROACH OF THE TROUGH EARLY SATURDAY MORNING. DID NOT LOWER
CEILINGS VERY MUCH DURING THIS TIME FRAME AND ANY PCPN WILL BE TOO
SPARSE AND UNCERTAIN TO INCLUDE IN THE TAF. AN IMPROVING TREND
RETURNS TOWARD MIDDAY SATURDAY.

WINDS DIMINISH LATE TODAY AS THE PRESSURE GRADIENT WEAKENS BUT THEY
STRENGTHEN AGAIN SATURDAY MORNING AS THE LOW OFF THE COAST
INTENSIFIES WITH THE APPROACH OF THE UPPER LEVEL TROUGH.

OUTLOOK...MAINLY DRY WEATHER DURING THE NEXT SEVERAL DAYS SHOULD
PROMOTE GOOD FLYING CONDITIONS.

&&

.MARINE...
COLD FRONT HAS LOCATED OFF THE SE COAST THIS AFTERNOON. AN AREA OF
LOW PRESSURE HAS DEVELOPED ALONG THE FRONT OFF THE SC COAST.
MEANWHILE...HIGH PRESSURE HAS CENTERED OVER THE GREAT LAKES REGION.
CURRENT OBS OVER THE WATER INDICATE NLY WINDS AVG 15-20 KT WITH
WAVES 2-4 FT AND SEAS 4-6 FT. SFC LOW LIFTS NEWD TONIGHT TONIGHT AS
HIGH PRESSURE REMAINS OVER THE GREAT LAKES. THIS WILL RESULT IN
ANOTHER SURGE TONIGHT. STRONGEST CAA ARRIVES AFTER MIDNIGHT...WITH
NW WINDS INCREASING TO 20-25 KT WITH GUSTS TO 30 KT OVER THE WATER.
HIGH PRESSURE SLOWLY BUILDS SEWD THRU SAT NIGHT-SUN
MORNING...RESULTING IN AN EXTENDED PERIOD OF CAA. SCA CONDITIONS
WILL LIKELY PERSIST THRU SUN MORNING UNTIL HIGH PRESSURE FINALLY
BUILDS OVER THE WATER. WAVES GENERALLY 3-4 FT AND SEAS 4-6 FT. NW
WINDS SUBSIDE TO 10-15 KT SUN AFTERNOON WITH SEAS DROPPING BELOW 5
FT. EXTENDED SCA HEADLINES THRU SUN MORNING. HIGH PRESSURE QUICKLY
PASSES OVER THE REGION SUN...AND THEN MOVES OFFSHORE SUN NIGHT. FLOW
SHIFTS TO THE SSW. THE NEXT (WEAK) COLD FRONT APPROACHES FROM THE W
LATE SUN. SW FLOW INCREASES LATE SUN NIGHT...WITH MODELS INDICATING
SCA CONDITIONS. HOWEVER...BASED ON WAA AND COLD WATER...DO NOT
ANTICIPATE SCA CONDITIONS. VERY LITTLE CAA IN WAKE OF THE FRONT LATE
SUN NIGHT-MON MORNING...SO SCA CONDITIONS ARE NOT ANTICIPATED
ATTM.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 1 AM SATURDAY TO 7 AM EDT SUNDAY FOR
     ANZ635>638.
     SMALL CRAFT ADVISORY UNTIL 11 AM EDT SUNDAY FOR ANZ630>634.
     SMALL CRAFT ADVISORY UNTIL NOON EDT SUNDAY FOR ANZ650-652-654-
     656-658.

&&

$$
SYNOPSIS...MPR
NEAR TERM...MPR
SHORT TERM...ALB/JDM
LONG TERM...SAM
AVIATION...LSA
MARINE...AJZ/SAM


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