Area Forecast Discussion
Issued by NWS Wakefield, VA

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KAKQ 202004
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
404 PM EDT WED AUG 20 2014

.SYNOPSIS...
A WARM FRONT SLOWLY LIFTS THROUGH THE REGION TONIGHT AND STALLS NEAR
THE COAST THURSDAY. A WEAK AREA OF LOW PRESSURE TRACKS ACROSS THE
NORTHERN MID ATLANTIC THURSDAY NIGHT...FOLLOWED BY ANOTHER LOW
PRESSURE SYSTEM FRIDAY NIGHT AND AN ASSOCIATED COLD FRONT. HIGH
PRESSURE BUILDS SOUTH FROM NEW ENGLAND OVER THE WEEKEND AS THE FRONT
PUSHES SOUTH OF THE REGION.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
THE LATEST SURFACE ANALYSIS INDICATES A BROAD ~1010MB LOW OVER THE
GREAT LAKES WITH A WARM FRONT EXTENDING S THROUGH THE OHIO VALLEY
AND CENTRAL APPALACHIANS. GOES WV IMAGERY INDICATES A SHORTWAVE
TROUGH AXIS EXTENDING S FROM THE MAIN MID-LEVEL LOW OVER THE GREAT
LAKES IN VICINITY OF THE SURFACE BOUNDARY. ISO-SCT CONVECTION HAS
DEVELOPED AHEAD OF THE TROUGH AXIS...WITH THE MOST ORGANIZED
ACTIVITY N OF THE LOCAL AREA FROM NRN VA INTO S-CENTRAL PA. THE WARM
FRONT AND MID-LEVEL TROUGH WILL SLOWLY TRACK W-E ACROSS THE REGION
THIS EVENING AND OVERNIGHT. A 20-30% POP WILL BE INCLUDED TO ACCOUNT
FOR THIS. OTHERWISE...EXPECT A WARM HUMID NIGHT WITH LOWS IN THE
UPPER 60S TO LOW 70S. PATCHY FOG/STRATUS IS POSSIBLE LATE GIVEN
ABUNDANT LOW-LEVEL MOISTURE AND LIGHT S FLOW.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
THE WARM FRONT STALLS IN VICINITY OF THE COAST THURSDAY. OVERALL
FORCING FOR CONVECTION IS WEAK. HOWEVER...A 20% POP WILL BE
MAINTAINED FOR THE EASTERN THIRD OF THE AREA DUE TO THE PRESENCE OF
THE SURFACE BOUNDARY. NW MID-LEVEL FLOW DEVELOPS THROUGH THE DAY
THURSDAY...WITH A WEAK IMPULSE PASSING THROUGH THE MID-ATLANTIC
THURSDAY NIGHT. THE BEST CHC OF SHOWERS/TSTMS SHOULD BE ACROSS NRN
PORTIONS IN CLOSER PROXIMITY TO THE SURFACE LOW. A MORE VIGOROUS
WAVE DROPS ACROSS THE REGION FRIDAY AFTERNOON/FRIDAY NIGHT ALONG
WITH AN ASSOCIATED COLD FRONT. THIS SHOULD PROVIDE BEST CHC OF AND
GREATEST AREAL COVERAGE OF SHOWERS/TSTMS ACROSS THE LOCAL AREA
DURING THE SHORT-TERM PERIOD DUE TO STRONGER UPPER JET SUPPORT. HIGH
PRESSURE BUILD OVER NEW ENGLAND SATURDAY AND PUSHES S INTO THE
MID-ATLANTIC. THIS WILL PUSH THE FRONT S OF THE AREA. AT THIS
TIME...POPS RANGE FORM SLIGHT CHC OVER NE PORTIONS TO CHC ACROSS
S/SW PORTIONS.

HIGHS SHOULD GENERALLY BE IN THE UPPER 80S/LOW 90S
THURSDAY/FRIDAY...BEFORE DROPPING BACK INTO THE LOW/MID 80S
(POSSIBLY UPPER 70S FAR NE) SATURDAY BEHIND THE FRONT. LOWS SHOULD
MAINLY BE IN THE UPPER 60S TO LOW 70S FRIDAY AND SATURDAY MORNINGS.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
DECREASING CHANCES FOR PRECIP AND NEAR SEASONABLE...LATE SUMMER
TEMPERATURES EXPECTED THRU THE EXTENDED PERIOD FORECAST.

UPPER FLOW CONTINUES TO BE DOMINATED BY BUILDING HIGH PRESSURE OVER
THE CNTRL CONUS AND LOW PRESSURE/TROUGHING OFF THE NE COAST. FLOW
REMAINS BLOCKED OVER ERN CANADA AND THE NERN US...RESULTING IN
LITTLE PROGRESSION OF THE CNTRL CONUS RIDGE THRU THE PERIOD. THE
RESULT WILL BE ONGOING NWLY FLOW INTO THE EARLY PERIOD. BACKDOOR
FRONT WILL PUSH WELL SOUTH OF THE LOCAL AREA SUN AS THE TROUGH
AMPLIFIES ALONG THE ERN SEABOARD. LATEST MODEL GUIDANCE HAS TRENDED
SLIGHTLY WETTER SUN AFTER PREVIOUSLY BRINGING IN DRIER AIR BEHIND
THE FRONT. SFC HIGH PRESSURE OVER THE NE STATES WILL RIDGE SWD OVER
THE LOCAL AREA IN WAKE OF THE FRONT...WITH SUBSIDENCE INDICATED IN
MODEL SOUNDINGS. MOISTURE ALSO LOOKS TO BE ON THE DOWNTREND AS MODEL
DERIVED PWATS DROP BELOW 1.5 INCHES. WITH THAT SAID...SUN MAY END UP
BEING DRY...BUT WILL RETAIN SLIGHT CHANCE POPS OVER THE PIEDMONT AND
COASTAL AREAS AS DISTURBANCES IN NWLY FLOW AND MODEL UNCERTAINTY
DECREASE CONFIDENCE. BETTER CONFIDENCE IN DRY CONDITIONS HEADING
INTO EARLY NEXT WEEK AS THE CNTRL CONUS HIGH BEGINS TO NUDGE IN FROM
THE WEST AND SUBSIDENCE ALOFT WINS OUT. BEST MOISTURE ALSO GETS
SHUNTED TO THE SOUTH AND WEST. TREND CONTINUES INTO TUES AND WEDS AS
HIGH PRESSURE BUILDS OVERHEAD AND DRY AIR AND SUBSIDENCE WIN OUT.

ONSHORE FLOW AND LOW-LEVEL THICKNESSES YIELD DAYTIME TEMPS GENERALLY
IN THE UPPER 70S TO LOWER 80S THRU TUES (-1 STD DEV FOR THIS TIME OF
YEAR). RETURN FLOW ON WEDS AND WARMING THICKNESSES PUSH TEMPS BACK
INTO THE MID 80S. LOWS GENERALLY IN THE LOW-MID 60S THRU THE PERIOD
AS DEWPOINTS REMAIN IN THE LOW-MID 60S.

&&

.AVIATION /20Z WEDNESDAY THROUGH MONDAY/...
A WEAK WARM FRONT WILL PUSH INTO AND ACRS THE REGION FM THE W
LATE THIS AFTN INTO THU. EXPECT MAINLY VFR/MVFR CONDITIONS DURING
MOST OF THE TAF PERIOD...WITH ISLTD/SCTD PCPN POSSIBLE LATE THIS
AFTN INTO EARLY THU MORNG. ISLTD IFR CONDITIONS POSSIBLE LATE TNGT
INTO EARLY THU MORNG...AS LIGHT ESE WINDS BECOME LIGHT SSW. LWR
CIGS AND VSBYS POSSIBLE THU NGT THRU SAT...DUE TO DECENT CHC FOR
SHOWERS/TSTMS.

&&

.MARINE...
LOW PRESSURE OFFSHORE AND HIGH PRESSURE RIDGING IN FROM THE NORTH
HAS RESULTED IN ONSHORE FLOW OVER THE WATERS THIS AFTERNOON. SPEEDS
AVG AROUND 10 KT WITH SEAS GENERALLY 3 FT AND WAVES 2 FT. WARM FRONT
WILL APPROACH THE WATERS TONIGHT FROM THE WEST AS THE RIDGE AXIS AND
SFC LOW PUSH FARTHER OUT TO SEA. THIS WILL VEER THE FLOW AROUND TO
THE SOUTH OVERNIGHT...AVG 10 KT. SEAS WILL BEGIN TO SUBSIDE TO 2-3
FT AND WAVES 1-2 FT. FRONTAL BOUNDARY STALLS NEAR THE WATERS THURS
AS ANOTHER WAVE OF LOW PRESSURE DEVELOPS OVER THE WATERS THURS
NIGHT-FRI MORNING. HIGH PRESSURE OVER THE NE STATES RIDGES SWD OVER
THE WATERS FRI NIGHT-SAT AS LOW PRESSURE PUSHES OFF THE NC COAST.
STRENGTHENING PRESSURE GRADIENT WILL RESULT IN INCREASING NELY WINDS
OVER THE COASTAL WATERS LATE FRI NIGHT THRU SAT. HIGH PRESSURE
REMAINS ANCHORED OFF THE NE COAST THRU EARLY NEXT WEEK RESULTING IN
PERSISTENT ONSHORE FLOW. ATTM...SPEEDS APPEAR TO REMAIN
SUB-SCA...BUT SEAS ARE FORECAST TO BUILD TO 4-5 FT LATE SAT THRU
MON.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...MODERATE RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR
     MDZ025.
NC...MODERATE RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR
     NCZ102.
VA...MODERATE RIP CURRENT RISK UNTIL 8 PM EDT THIS EVENING FOR
     VAZ098>100.
MARINE...NONE.

&&

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




USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.