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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KAKQ 171451
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
1051 AM EDT MON JUN 17 2013

.SYNOPSIS...
A WEAK FRONTAL BOUNDARY REMAINS TO THE NORTH OF THE REGION TODAY
AND TONIGHT. THIS FRONT WILL MOVE SOUTHWARD THROUGH THE LOCAL AREA
ON TUESDAY...THEN WASHES OUT OVER THE CAROLINAS ON WEDNESDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
LATEST WATER VAPOR IMAGERY SHOWS BROAD CYCLONIC FLOW OVER MUCH OF
THE CNTRL AND ERN CONUS THIS MORNING AS A HIGH PRESSURE RIDGE
BUILDS OVER THE WRN CONUS. SEVERAL WEAK VORTICITY MAXIMA WILL
TRAVERSE THE FLOW REGIME TODAY...WITH THE FIRST SUCH MAXIMA AIDING
IN THE DEVELOPMENT OF SHOWERS OVER THE LOCAL AREA THIS MORNING. AS
WEAK VORT MAXIMA PROVIDE SUBTLE FORCING FOR ASCENT...WEAK LEE
SIDE SFC TROUGH AND PRECIP WATERS INCREASING UPWARDS OF 1.8 INCHES
WILL CONTINUE TO PRODUCE SCATTERED SHOWERS THROUGH THE AFTERNOON.
THETA-E ADVECTION WITH WARM AFTERNOON TEMPS AND DEWPOINTS IN THE
UPPER 60S WILL MAINTAIN A MARGINALLY UNSTABLE AIRMASS (0-6KM
MUCAPE ~1200-1500 J/KG) OVER THE LOCAL AREA. BIGGEST LIMITATIONS
TO STRONG THUNDERSTORMS WILL BE RATHER WEAK MID LEVEL LAPSE
RATES...CLOUD COVER AND A LACK OF STRONG UPPER LEVEL SUPPORT.
ALSO...LIMITED CAPE IN MIXED PHASE LAYER WILL ALSO LIMIT LIGHTNING
POTENTIAL. HOWEVER...NEARLY 150% OF NORMAL PRECIP WATERS AND
STEEP LOW LEVEL LAPSE RATES MAY RESULT IN BRIEF HEAVY RAINFALL AND
WIND GUSTS UP TO 35 MPH. 0-6KM BULK SHEAR AROUND 25 KT WILL ALSO
LIMIT ORGANIZED CONVECTION. LATEST PRECIP GUIDANCE HANDLES THE
SITUATION WELL...SO HAVE EXPANDED HIGH END CHANCE POPS OVER SE
VA/NE NC...WITH BEST CHANCES BEING SOUTH AND EAST TO RICHMOND. WLY
MID LEVEL DRY AIR WILL ENTRAIN INTO THE PIEDMONT THIS
EVENING...STABILIZING THE ERN AND NWRN ZONES. HAVE OPTED TO
DECREASE POPS TO SLIGHT CHANCE THIS EVENING AND TONIGHT OVER THAT
REGION. VORT MAX LIFTING THROUGH THE CAROLINAS WILL PROVIDE LOW
END CHANCE POPS OVER EXTREME SE VA/NE NC TONIGHT. QPF AMOUNTS WILL
BE LIMITED BY COVERAGE...WITH AMOUNTS GENERALLY LESS THAN HALF AN
INCH.

SEASONABLY WARM TODAY WITH AFTERNOON TEMPS IN THE MID/UPPER 80S.
MILD TONIGHT WITH LOWS IN THE UPPER 60S/LOW 70S.
-- End Changed Discussion --

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
A MORE POTENT SHORTWAVE WILL DIVE SE THRU THE GREAT LAKES/MIDWEST
ON TUESDAY...THEN MOVES ACROSS THE MID-ATLANTIC STATES ON
WEDNESDAY. THIS FEATURE WILL DRIVE A COLD FRONT SOUTHWARD THROUGH
THE LOCAL AREA LATE TUESDAY/TUESDAY NIGHT. MODELS SHOW
SHWRS/TSTMS DEVELOPING ALONG/SOUTH OF THE FRONT AND WITH INFLUENCE
OF APPROACHING S/W WILL CARRY HIGH END CHC POPS TO HIGHLIGHT GOOD
POTENTIAL FOR WIDESPREAD PCPN. THREAT FOR SVR WX ON TUESDAY DOES
NOT LOOK AS GOOD A PREVIOUS RUNS...BUT GIVEN HIGH PWAT`S AROUND
1.75" COULD BE SOME HEAVY DOWNPOURS. HIGHS TUES IN THE 80S.

SFC FRONT MOVES SOUTH INTO NC TUESDAY NIGHT AND WEDNESDAY.
HOWEVER...S/W MOVING ACROSS THE AREA WILL KEEP A DECENT CHC OF
PCPN GOING INTO WED. WINDS TURN N/NE BEHIND THE FRONT ON WED AND
ATMOS STABILIZES A BIT MORE FOR DECREASED THREAT OF TSTMS. SLIGHTLY
COOLER MAX TEMPS EXPECTED AS WELL. LOWS TUES NIGHT IN THE 60S.
HIGHS WED IN LOW 80S.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
DRY CONDITIONS AND BELOW NORMAL TEMPS WILL HIGHLIGHT THE BEGINNING
OF THE EXTENDED PERIOD...FOLLOWED BY A RETURN TO NEAR SEASONABLE
TEMPS BY THE WEEKEND.

PERSISTENT BLOCKY PATTERN...WRN TROUGH/PLAINS RIDGE/ERN TROUGH WILL
CONTINUE THROUGH THE BEGINNING OF THE EXTENDED. THE RIDGE WILL BEGIN
TO RELAX AS A STRONG POLAR LOW LOCATES OVER THE HUDSON BAY
THURS-FRI. THE NW UPPER LOW WILL LIFT NEWD INTO SRN CANADA
FRI...RESULTING IN A SLOW EWD PROGRESSION OF THE FLATTER/WEAKER
UPPER RIDGE AND THE DEVELOPMENT OF STRONG HIGH PRESSURE (+1 STD DEV
H5 HEIGHTS) OVER THE SRN PLAINS. OVER THE LOCAL AREA...BAGGY
TROUGH/WEAKNESS UNDER THE RIDGE WILL REMAIN ORIENTED ALONG THE
SE/MID ATLANTIC COAST THROUGH THE EXTENDED PERIOD...RESULTING IN
NWLY FLOW ALOFT. AT THE SFC...HIGH PRESSURE WILL BUILD OVER THE MID
ATLANTIC THURS...BEFORE SLIDING OFFSHORE FRIDAY...AND REMAINING
ALONG THE COAST THROUGH THE WEEKEND. THIS WILL RESULT IN ONSHORE
E-SE FLOW WITH S/SW FLOW RETURNING SAT INTO SUNDAY AS THE UPPER
TROUGH WEAKENS. DRY CONDITIONS (DEWPOINTS GENERALLY IN THE LOW 60S
AND PRECIP WATER AOB 1.5 INCHES) EXPECTED THROUGH SAT. MOISTURE WILL
BEGIN TO RETURN TO THE REGION SAT AND SUN. OPTED TO INCLUDE CLIMO
POPS (SLIGHT CHANCE) SAT AND SUN AFTERNOON DUE TO INCREASING
MOISTURE AND THE POSSIBILITY OF DIURNALLY DRIVEN THUNDERSTORMS IN
NWLY FLOW.

BIGGEST CHANGE IN THE CURRENT EXTENDED RELATES TO DAYTIME TEMPS.
LOWER HEIGHTS/LOW LEVEL THICKNESSES AND E/SE ONSHORE SFC WINDS WILL
RESULT IN BELOW NORMAL TEMPS THURS AND FRI. DAYTIME TEMPS EXPECTED
TO ONLY WARM INTO THE LOW 80S THURS (~-1 STD DEV) WITH ONLY A FEW
DEGS WARMING FRI (ONLY MID/UPPER 70S ALONG THE IMMEDIATE COAST.
INLAND FLOW WILL RETURN TO THE S SAT AND SUN...WITH TEMPS RETURNING
TO NEAR SEASONABLE NORMS (MID/UPPER 80S)...BUT STILL SEVERAL DEGS
COOLER ALONG THE COAST. OVERNIGHT LOWS GENERALLY IN THE LOW/MID 60S.

&&

.AVIATION /15Z MONDAY THROUGH FRIDAY/...
WEAKING SURFACE TROUGH CONTS TO SETTLE OVER THE RGN. BAND OF
RA W/ ISOLD T MOVING THROUGH CNTRL PORTIONS OF THE FA. AXIS OF
MOISTURE SLOLY SINKING TO THE SE...XPCG AT LEAST A SHORT PD OF RA
AT KORF/KPHF/KECG THIS MRNG. OTRW...CIGS MNLY AOA 3-5KFT INTO THE
MID/LT MRNG HRS. CONTD SW FLO THROUGH REST OF THE DAY...LO PROB
FOR ISOLD/SCT SHRAS/TSRAS THIS AFTN/EVE. WK LO PRES APPROACHES FM
THE W TUE...RESULTING IN INCRSG RA CHCS AND PROB FOR SHORT PDS OF
MVFR CIGS/VSBYS (INTO WED).

&&

.MARINE...
DECIDED TO RAISE SHORT PD SCA (UNTIL 13Z/17) FOR LWR JAMES
RIVER/SRN BAY DUE TO CONTD SW WNDS AVGG 15 TO 20 KT.

WKNG SFC FNTL BNDRY/TROUGH DRIFTS OVR THE WTRS ERY TDA...THEN
DISSIPATES. CONTD MSTLY SW INTO TNGT AS HI PRES RMNS OFF THE SE
CONUS CST...SPDS AVGG AOB 15 KT (AFT ERY TDA). WK SFC LO PRES
APPROACHES FM THE W TUE...THEN TRACKS THROUGH THE WTRS LT TUE NGT
INTO WED. MDLS A LTL MORE IN LINE W/ WNDS SHIFTING TO NNE ON
WED...THOUGH THERE RMN NOTABLE SPD DIFFERENCES (GFS SHOWING MUCH
BETTER PTNTL FOR A SURGE IN SPDS BY WED AFTN INTO WED EVE BEFORE
SUBSIDING). AT THIS POINT...CONTG W/ ONLY MINOR ADJUSTMENTS TO
WNDS/WAVES-SEAS MIDWEEK BASED ON UNCERTAINTY. SFC HI PRES FM THE N
XPCD TO SLOLY DRIFT OFF THE SRN NEW ENG CST BY LT THU INTO
FRI...RESULTING IN CONTD ONSHR WNDS (ENE). NO SCAS PLANNED FM THIS
AFTN INTO WED.

&&

.AKQ WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
MD...NONE.
NC...NONE.
VA...NONE.
MARINE...NONE.
-- End Changed Discussion --

&&

$$
SYNOPSIS...JDM
NEAR TERM...SAM
SHORT TERM...JDM
LONG TERM...SAM
AVIATION...ALB
MARINE...ALB