Area Forecast Discussion
Issued by NWS Wakefield, VA

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000
FXUS61 KAKQ 200802
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
402 AM EDT WED AUG 20 2014

.SYNOPSIS...
A WARM FRONT SLOWLY PULLS NORTH INTO THE AREA TODAY...THEN REMAINS
NEARLY STATIONARY ACROSS THE AREA INTO THE UPCOMING WEEKEND.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
WK SFC LO PRES OFFSHORE CONTS TO SLOLY MOVE E AND AWAY FM THE
MDATLC CST TDA. LINGERING FNTL BNDRY S OF THE FA THIS MRNG...W/
SFC HI PRES TO THE NNE...RESULTING IN CONTD SFC FLO FM THE ENE
ACRS THE FA (IN THE WAKE OF DEPARTING SFC LO PRES). REMNANT BNDRY
TO THE S PULLS SLOLY N INTO THE FA TDA AS WK SFC LO PRES INVOF
LAKES/UPR OH VLY APPROACHES FM THE WNW. ISOLD/SCT CONVECTION ALG
WK CDFNT AND ASSOCIATED W/ MID/UPR LVL S/W MOVING THROUGH ERN OH
VLY ATTM. DURG TDA...PATCHY FG TO START...THOUGH RIGHT NOW NOT
ENOUGH TO INCLUDE IN FCST...THEN XPCG VRB CLDS TO PCLDY WX ACRS
FA. MAY BE AN ISOLD SHRA INVOF CSTL SE VA/NE NC THIS MRNG...AND
PSBLY FAR WNW AREAS IN FA. OTRW...FM MIDDAY THROUGH AFTN/EVE
HRS...SCT CONVECTION PSBL...ESP NRN PORTION OF FA...AS SYS PASSES
BY JUST TO THE N OF THE FA. HI TEMPS FM THE L/M80S AT THE CST...TO
M/U80S INLAND.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/...
THE OVERALL PATTERN IS AGREED UPON IN THE MID RANGE PART OF THE
FORECAST AS THE UPPER LOW OVER THE GREAT LAKES SLIDES INTO THE
EAST AND THE UPPER RIDGE OVER THE MS VALLEY BUILDS
NORTHWARD...SETTING UP NW FLO ALOFT OVER OF THE MID ATLANTIC
REGION. HOWEVER...BEYOND THE THAT...THE TIMING OF INDIVIDUAL WAVES
AND THE POTENTIAL FOR CONVECTIVE COMPLEXES MAKES THE TIMING OF
PRECIPITATION VERY UNCERTAIN FOR THURSDAY AND FRIDAY. AT THE
SURFACE...A WK FRONTAL BOUNDARY THAT WILL BE IN THE VICINITY SHOULD
BE SOME STATIONARY AND NRLY PARALLEL TO THE FLOW ALOFT AND COULD
ALSO BE A FOCUS FOR CONVECTION. AT THIS POINT...WITH THE
UNCERTAINTY...WILL CONT TO LEAN MORE TOWARD CLIMATOLOGY WITH BEST
CHANCES IN THE PIEDMONT EARLY IN THE AFTERNOON AND THEN AREA WIDE
IN LATE AFTERNOON THROUGH ABOUT MIDNIGHT.

LO TEMPS TNGT FM THE M60S TO ARND 70F. HI TEMPS THU FM THE M80S AT
THE CST TO L90S INLAND. HI TEMPS FRI IN THE L/M80S.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
UNSETTLED WEATHER PATTERN CONTINUES INTO THE EXTENDED PERIOD IN NWLY
FLOW ALOFT...BUT DRIER CONDITIONS EXPECTED BY EARLY NEXT WEEK. TEMPS
WILL BE SLIGHTLY BELOW SEASONABLE...LATE SUMMER NORMS TO BEGIN THE
EXTENDED BEFORE RETURNING TO NEAR NORMAL EARLY NEXT WEEK.

UPPER LEVEL FLOW DURING THE EXTENDED IS HIGHLIGHTED BY SPLIT/BLOCKY
FLOW OFF THE ERN CANADA AND NERN US COAST AND AMPLIFYING HIGH
PRESSURE OVER THE SRN CONUS. THIS PLACES THE MID-ATLANTIC REGION IN
NWLY FLOW ALOFT. ASSOCIATED BACK DOOR FRONT WILL PUSH SOUTH OF THE
LOCAL AREA SATURDAY MORNING. SFC HIGH PRESSURE PROGGED OVER THE NE
WILL RIDGE SWWD ALONG THE COAST AND INTO CNTRL VA. NLY LOW-LEVEL
FLOW INDICATED IN MEDIUM RANGE GUIDANCE WILL DRIVE DEWPOINTS
DOWNWARD INTO THE MID 60S. HOWEVER...MODEL DERIVED PWATS REMAIN
AROUND 1.8 TO 2.0 INCHES. COMBINED WITH PERTURBATIONS IN THE NWLY
FLOW...WILL HAVE MNLY CLDY WX AND MAINTAIN CHANCE POPS FOR
DIURNALLY DRIVEN SHOWERS/THUNDERSTORMS. WILL ALSO NEED TO WATCH
FOR POSSIBLE MCS DEVELOPMENT UPSTREAM...ROUNDING THE RIDGE AND
DROPPING INTO THE REGION OVERNIGHT THRU THE WEEKEND. BY EARLY NEXT
WEEK THE RIDGE AXIS WILL BEGIN TO BUILD INTO THE REGION AS SFC
HIGH PRESSURE IS PROGGED TO LOCATE OFF THE COAST. BLOCK WILL
REMAIN OFF THE NE COAST...BUT MOISTURE FEED WILL BE CUT OFF.
DECREASING MOISTURE AND INCREASING SUBSIDENCE WILL LIKELY RESULT
IN DRY CONDITIONS. HOWEVER...CONFIDENCE IS NOT HIGH ATTM...SO WILL
LEAVE POPS SILENT.

NORTH OF THE BOUNDARY...THICKNESSES AND GUIDANCE YIELD TEMPS IN THE
LOW TO MID 80S THRU MONDAY (AROUND -1 STD DEV). OVERNIGHT LOWS
GENERALLY IN THE UPPER 60S TO LOW 70S NEAR THE WATER. WARMING BACK
UP TO NEAR SEASONABLE NORMS TOWARD THE MIDDLE OF NEXT WEEK.

&&

.AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
HIGH PRESSURE BRIEFLY BUILDS OVER THE AREA FROM THE NORTH BEHIND
DEPARTING LOW PRESSURE SYSTEM. UPPER LEVEL SHORT WAVES IN A W/NW
FLOW WILL KEEP CONDITIONS UNSETTLED FOR THE NEXT SEVERAL DAYS. MOIST
GROUND AND LOW LEVEL CONDITIONS WILL MAINTAIN THE CHC FOR ISSUES
WITH CIG/VSBY EACH MORNING.

AS OF 06Z...NE WINDS PREVAILED AT THE TAF SITES WITH NO PCPN
EXPECTED EARLY THIS MORNING. SKY CONDITIONS WILL BE VARIABLE WITH
GRADUAL LOWERING OF CIGS AND VSBYS. THE MAIN LIMITATION IS
INDICATED TO BE CIGS BUT VSBYS ARE NOT OFF THE TABLE. USED THE
RESULTS OF THE PREVIOUS OVERNIGHT AS A PARTIAL GUIDE AND A MIX OF
MOS GUIDANCE TO MAKE A PLAN FOR THE CURRENT TAF. DESPITE ECG
HAVING THE CLOSEST T/TD SPREAD...EXPERIENCE WOULD INDICATE THEY
MAY NOT GO DOWN TO IFR FOR A WHILE (I.E. AROUND 12Z) AND MAY HAVE
NO LOWER THAN MVFR. HAVE RIC/PHF WITH SOME PERIODS OF IFR. SBY MOS
IS BIASED BY TEMPERATURES THAT ARE TOO LOW. KEPT ORF OUT OF IFR
DUE TO CLIMATOLOGY.

CONDITIONS SHOULD BE VFR BY AROUND 14-15Z. LATER TODAY...THERE
WILL BE A CHC FOR LATE AFTN/EVENING TSTMS...ESPECIALLY NORTH
PORTIONS. WINDS VEER TOWARD E/SE.

OUTLOOK...CHC FOR AFTN TSTMS THURSDAY THROUGH SATURDAY. SOME
MVFR/IFR PSBL NEAR SUNRISE EACH MORNING. CURRENT FORECAST IS DRY ON
SUNDAY.

&&

.MARINE...
NO HEADLINES NEC WITH THIS FORECAST PACKAGE. HI PRES PERSISTS JUST N
OF THE AREA TDA AS LO PRES AND AN ASSOCIATED FRNTAL BNDRY SLOWLY
SLIDE SE OF THE WTRS. THE RESULT WILL BE NE FLOW MAINLY 5-10 KT OVR
THE BAY/SOUND/RIVERS AND 10-15 KT OVR CSTL WTRS. EXPECT 2-3 FT SEAS
OVR THE OCEAN AND 1-2 FT WAVES OVR THE BAY FOR TDA INTO TNGT.
SUB-SCA CONDITIONS CONTINUE AS THE AFOREMENTIONED BNDRY LIFTS N AS A
WARM FRNT THU INTO FRI...THEN SLIDES OFFSHORE OVR THE WEEKEND.
DURING THE WEEKEND...THE PRES GRADIENT TIGHTENS WITH NELY WINDS
INCREASING TO 10-20 KT. THIS WILL PUSH SEAS IN THE NRN WATERS TO 3-4
FT...WITH 5 FT PSBL 20NM OUT.

&&

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

&&

$$
SYNOPSIS...ALB/ESS
NEAR TERM...ALB/ESS/JAO
SHORT TERM...ESS
LONG TERM...SAM
AVIATION...MAS/LSA
MARINE...MAS














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