Area Forecast Discussion
Issued by NWS Wakefield, VA

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000
FXUS61 KAKQ 211457
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
1057 AM EDT MON APR 21 2014

.SYNOPSIS...
LOW PRESSURE OFF THE CAROLINA COAST...WILL TRACK SLOWLY NORTHEAST
INTO THE ATLANTIC THROUGH TODAY...AS HIGH PRESSURE SLIDES OFF THE
NEW ENGLAND COAST. A COLD FRONT WILL CROSS THE AREA TUESDAY
AFTERNOON INTO TUESDAY NIGHT. HIGH PRESSURE RETURNS FOR WEDNESDAY
AND THURSDAY.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
LATEST WATER VAPOR IMAGERY SHOWS SRN STREAM UPPER LOW LOCATED OFF
THE SOUTHEAST COAST...SLOWLY PUSHING OUT TO SEA. AT THE
SFC...COASTAL LOW REMAINS ANCHORED OFF THE CAROLINA COAST AS HIGH
PRESSURE REMAINS RIDGED OVER THE LOCAL AREA (ONGOING NE FLOW). LOW
CLOUDS/STRATUS STILL HANGING ON OVER SE VA/NE NC...BUT WILL THIN/ERODE
BY LATE MORNING. SUNNY ELSEWHERE. RADAR RETURNS REMAIN CONFINED
OFF THE NC COAST...AND MOVING OFFSHORE.

FOR TODAY...SRN STREAM SPEED MAX WILL BEGIN TO PUSH THE UPPER LOW
AND ASSOCIATED MOISTURE FARTHER OFFSHORE...RESULTING IN DRY
CONDITIONS AND SUNNY-MOSTLY SUNNY SKIES. SPLIT FLOW OVER THE
CONUS WILL FEATURE A NRN STREAM SHORTWAVE OVER SRN CANADA AND A
SRN STREAM DISTURBANCE OVER THE SRN PLAINS. THESE FEATURES WILL
BEGIN TO PHASE OVER THE CNTRL CONUS TODAY AS THEY MARCH
EWD...PUSHING AN ASSOCIATED COLD FRONT OUT IN ADVANCE. AMPLIFYING
FLOW WILL BUILD A SHORTWAVE RIDGE OVER THE LOCAL AREA TODAY WITH
THE UPPER FLOW BECOMING NWLY THIS AFTERNOON. HOWEVER...LOW
LEVEL/SFC N-NE FLOW WILL PERSIST. INCREASING LOW LEVEL
THICKNESS/WAA WILL WARM TEMPS INTO THE LOW 70S OVER INTERIOR
VA/NC(REGARDLESS OF NELY FLOW)...BUT NE FLOW NEAR THE COAST WILL ONLY
PRODUCE TEMPS IN THE MID-UPPER 50S.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/...
COLD FRONT TRACKING INTO THE OH VLY MON EVENG...WILL PUSH E AND
OVR THE MTNS TUE MORNG. THAT FRONT WILL BRING INCREASING CLOUDS FM
W TO E TUE...ALONG WITH A CHC FOR SHOWERS. MOST OF IF NOT ALL THE
SHOWERS MAY HOLD OFF UNTIL THE AFTN W...AND TWD LATE AFTN/EVENG E
ON TUE. WILL MAINTAIN A SLGT CHC OF A TSTM...THOUGH DYNAMICS
WEAKENING WITH TIME...AS THE FRONT ENTERS THE AREA. LO TEMPS MON
NGT WILL RANGE FM THE MID 40S TO NEAR 50. HI TEMPS ON TUE WILL
RANGE FM THE MID TO UPR 70S INLAND...TO THE UPR 60S TO LWR 70S AT
THE CST.

THE COLD FRONT WILL PUSH OUT TO SEA TUE NGT...WITH SGFNT DRYING
AND A PERIOD OF COOLING THEREAFTER (FM AFTR MIDNGT TUE NGT THRU WED).
MAINTAINING 30-40% POPS ERN PORTION OF THE FA TUE EVENG...15-25%
ELSEWHERE...THEN CLEARING AFTR MIDNGT...AS WINDS BECOME NW. NEAR
SEASONABLE/CLEAR-PRTLY CLOUDY WX THEN EXPECTED WED WITH GUSTY NW
WINDS...MAINLY ERN PORTION. LO TEMPS TUE NGT RANGING FM THE MID
40S NW TO THE LWR 50S SE. HI TEMPS ON WED WILL RANGE THRU THE 60S.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
PROGRESSIVE FLOW WILL RESULT IN NEAR SEASONABLE NORMAL TEMPS AND
GENERALLY DRY CONDITIONS THROUGH THE EXTENDED PERIOD FORECAST. A
COLD FRONT WILL BRING A CHANCE OF SHOWERS TO THE REGION FRIDAY
AFTERNOON INTO FRIDAY NIGHT.

TROUGH AXIS WILL PUSH OFF THE NE COAST WEDS NIGHT AS AN UPPER
LEVEL RIDGE BUILDS EWD OVER THE CNTRL-ERN CONUS. AT THE SFC...COOL
CANADIAN HIGH PRESSURE WILL BUILD SEWD FROM THE GREAT LAKES INTO
THE MID-ATLANTIC REGION WEDS NIGHT-THURS. THIS WILL RESULT IN
ANOTHER COOL DAY THURS (HIGHS GENERALLY IN THE MID-UPPER 60S) AS
FLOW REMAINS NW-W. SFC HIGH WILL SLIDE OVER THE LOCAL AREA THURS-
LATE THURS...LOCATING OFFSHORE THURS NIGHT. THIS WILL VEER THE
FLOW AROUND TO THE SOUTH AS THE UPPER RIDGE AXIS BUILDS OVERHEAD.
MEDIUM RANGE GUIDANCE IS COMING INTO BETTER AGREEMENT...BUT
CONTINUE TO STRUGGLE WITH THE EVOLUTION OF AN UPPER TROUGH OVER
THE INTERMOUNTAIN WEST INTO THE NRN PLAINS THURS-THURS NIGHT.
HOWEVER...GUIDANCE IS IN FAIRLY GOOD AGREEMENT WITH LIFTING A WARM
FRONT OVER THE REGION IN THE AMPLIFYING FLOW. TRAILING COLD FRONT
FORECAST TO CROSS THE REGION FRIDAY AFTERNOON. WLY FLOW OVER THE
SRN PLAINS INTO THE GULF STATES WILL LIMIT THE AMOUNT OF MOISTURE
ADVECTION INTO THE REGION...ESPECIALLY EAST OF THE APPALACHIANS.
DEWPOINTS ONLY PROGGED TO WARM INTO THE LOW-MID 50S FRI. BEST
DYNAMICS WILL ALSO REMAIN NORTH OF THE LOCAL AREA AS ZONAL FLOW
PREVAILS OVER THE LOCAL AREA. HOWEVER...INCREASING SPEEDS ALOFT
AND SMALL AMPLITUDE SHORTWAVES WILL BE ENOUGH TO MENTION SLIGHT
CHANCE-LOW END CHANCE POPS ALONG THE FRONT ATTM. WITH THE LOCAL
AREA IN THE WARM SECTOR FRI...TEMPS WILL WARM INTO THE MID-UPPER
70S (NEAR 80 INLAND). WARM TEMPS COMBINED WITH LOW LEVEL THETA-E
ADVECTION WILL MAINTAIN A MARGINALLY UNSTABLE AIRMASS OVER THE
REGION FRI AFTERNOON. THUS WILL CARRY A SLIGHT CHANCE OF THUNDER.
SRN PORTION OF THE FRONT WILL LIKELY STALL OVER THE CAROLINAS FRI
NIGHT-SAT IN WLY FLOW ALOFT. COOL CANADIAN HIGH PRESSURE WILL BE
SLOW TO BUILD OVER THE REGION AS THE TROUGH REMAINS OVER THE NE
STATES THRU THE WEEKEND. THIS WILL RESULT IN ANOTHER WARM DAY SAT
WITH HIGHS IN THE MID-UPPER 70S IN WLY FLOW. COOLER SUNDAY AS COOL
CANADIAN HIGH PRESSURE FINALLY BUILDS SEWD OVER THE REGION.

&&

.AVIATION /15Z MONDAY THROUGH FRIDAY/...
THE PRESSURE GRADIENT BETWEEN HIGH PRESSURE OVER NEW ENGLAND AND LOW
PRESSURE WELL OFF THE CAROLINA COAST WILL CONTINUE TO SLOWLY
SLACKEN THROUGH THE TAF PERIOD. HAVE HAD A BRIEF WINDOW OF IFR AT
ORF/ECG THIS MORNING, AND ACCOUNTED FOR THAT THROUGH THE NEXT FEW
HRS, WITH CIGS QUICKLY IMPROVING TO VFR BY 15-17Z. SOME GUSTS TO
20 KT THROUGH MIDDAY BEFORE EASING AS GRADIENT SLACKENS.

OUTLOOK...SOME PATCHY FOG IS PSBL LATE TONIGHT/ TUESDAY MORNING
BUT CURRENT PROBS DO NOT POINT TO WIDESPREAD IFR. A COLD FRONT
MOVES ACROSS THE REGION LATE TUESDAY...AND THERE IS A GOOD CHANCE
FOR SHOWERS AND A FEW THUNDERSTORMS TUESDAY AFTN AND EVENING WITH
A BRIEF WINDOW OF FLIGHT RESTRICTIONS POSSIBLE. HIGH PRESSURE
RETURNS WEDNESDAY AND THURSDAY. THERE WILL ONCE AGAIN BE A CHANCE
FOR SHOWERS AND THUNDERSTORMS ON FRIDAY.

&&

.MARINE...
LATEST OBS REFLECT CONTINUED NE WINDS OVER THE WATERS THIS MORNING.
WINDS HAVE DIMINISHED SLIGHTLY OVER THE PAST FEW HOURS AS LOW
PRESSURE SLOWLY PUSHES E-NE AWAY FROM THE SOUTHEAST COAST THIS
MORNING AND HIGH PRESSURE PUSHES OFF THE NE COAST. AS SFC LOW
IS STILL SLOWLY PUSHING FARTHER OFFSHORE, SCA WILL REMAIN IN PLACE
OVER THE BAY AND LOWER JAMES UNTIL MID-MORNING, AND THE MOUTH OF
THE BAY (FOR SEAS AND GUSTS TO 20 KT) AND CURRITUCK SOUND THROUGH
THIS AFTN. STILL NOTING SEAS OF 7-11FT OVER THE COASTAL WATERS
AT 11Z, AND SEAS WILL BE SLOW TO DIMINISH TODAY THROUGH TONIGHT.
THUS SCA REMAINS IN PLACE OVER THE ATLANTIC COASTAL WATERS UNTIL
LATE TONIGHT.

SFC LOW WILL PUSH FARTHER OUT TO SEA THROUGH TONIGHT AS HIGH
PRESSURE REMAINS RIDGED OVER THE WATERS. SEAS WILL SUBSIDE TO 4-8 FT
BY THIS AFTN. FLOW VEERS AROUND TO THE SOUTH TONIGHT, IN ADVANCE OF
A COLD FRONT APPROACHING FROM THE WEST. SEAS FINALLY FALL BELOW 5FT
BY TUE MORNING. COULD HAVE A FEW GUSTS TO LOW END SCA OVER THE
BAY/SND IN S-SW FLOW AHEAD OF THE FRONT ON TUESDAY, BUT EXPECT
PREDOMINATE CONDITIONS TO BE SUB-SCA. THE FRONT CROSSES THE WATERS
TUESDAY NIGHT, WITH A PERIOD OF SCA EXPECTED WITH RESULTANT N-NWLY
CAA SURGE LATE TUESDAY NIGHT AND WEDNESDAY. AFTER A SHORT LIVED
SECONDARY SURGE WED NGT, QUIETER MARINE CONDITIONS ARE EXPECTED AS
HIGH PRESSURE BUILDS OVER THE AREA FROM THE WEST THU.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 4 PM EDT THIS AFTERNOON FOR ANZ633-
     634.
     SMALL CRAFT ADVISORY UNTIL 6 AM EDT TUESDAY FOR ANZ650-652-654-
     656-658.

&&

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






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