-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KAKQ 100555
AFDAKQ

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
155 AM EDT THU JUL 10 2014

.SYNOPSIS...
A COLD FRONT APPROACHES FROM THE NORTHWEST OVERNIGHT...THEN
STALLS OVER VIRGINIA AND NORTH CAROLINA THURSDAY INTO FRIDAY. THE
FRONT WILL DISSIPATE FRIDAY NIGHT AS HIGH PRESSURE OVER THE
NORTHEAST BUILDS SOUTH OFF THE MID ATLANTIC COAST.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
KAKQ/KDOX RADARS SHOWING SHOWERS AND THUNDERSTORMS HAVE LARGELY
WEAKENED/DECREASED IN AREAL COVERAGE WITH THE EXCEPTION OF ACROSS
NE NC ALONG REMNANT THETA-E RIDGE. LATE EVENING GOES WV SAT
IMAGERY SHOWS A DISTURBANCE ROLLING ACROSS THE E TN/WESTERN
CAROLINAS, SO HV RETAINED A LOW CHC POP OVERNIGHT ACROSS THE
SOUTH...AND MAINLY DRY ELSEWHERE. OTHERWISE, KEPT POPS RATHER
CLOSE TO CURRENT OBS, WITH TEMPS FALLING OFF VERY LITTLE
OVERNIGHT. LOWS GENERALLY IN THE LOW TO MID 70S UNDER A MOSTLY
CLOUDY SKY.

PREVIOUS DISCUSSION...

LATEST ANALYSIS SHOWING SFC TROUGHINESS OVER THE
REGION...WITH A COLD FRONT SITUATED FROM EASTERN NY STATE TO THE
OHIO VALLEY. ALOFT...A DEEP UPPER LOW IS CENTERED TO THE SE OF
HUDSON BAY. SEVERAL SHORTWAVES ARE MOVING THROUGH THE WSW FLOW
ALOFT...THE MOST NOTABLE OVER CENTRAL/WRN NC. AREAS OF CONVECTION
HAVE DEVELOPED IN THE WARM/HUMID AIRMASS ACRS THE LOCAL AREA...ONE
AFFECTING THE PIEDMONT AND ANOTHER TO THE SE FROM NORTHAMPTON NC
TO THE PENINSULA. HAVE GONE WITH LIKELY POPS IN THESE AREAS FOR
THE NEXT FEW HRS BASED ON THIS SETUP (WITH GENLY SCATTERED 30-50%
COVERAGE ELSEWHERE). A FEW MARGINALLY SEVERE STORMS MAY OCCUR BUT
OVERALL MOST OF THESE ARE EXPECTED TO PRODUCE HEAVY RAIN AND BRIEF
WIND GUSTS MORE ON THE ORDER OF 30-40 MPH. LATER THIS
EVENING...HAVE LIKELY POPS FOCUSED OVER SE VA.INTERIOR NE NC PER
LATEST UPSTREAM RADAR AS WELL AS HIGH RES MODEL OUTPUT. WARM/HUMID
OVERNIGHT...ALTHOUGH A TAD COOLER THAN PREVIOUS FEW NIGHTS WITH
LOWS IN THE UPPER 60S W/NW TO LWR-MID 70S SE.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 AM FRIDAY/...
GFS/NAM IN GOOD AGREEMENT THAT THE SFC FRONT WILL STALL OVER THE
LOCAL AREA ON THU. MAKES SENSE GIVEN A FLATTENING WSW FLOW ALOFT
ALIGNING NEARLY PARALLEL WITH THE SFC FRONT. HAVE BUMPED AFTN
POPS UP TO LIKELY ACRS SE VA/NE NC...WITH HIGH CHC (50%) IN
CENTRAL VA...ALTHOUGH IF TRENDS HOLD COULD SEE THESE AREAS NEEDING
LIKELY POPS AS WELL. TEMPS HELD DOWN A BIT DUE TO THE CLOUD
COVERAGE/PCPN. HIGHS MAINLY IN THE MID/UPPER 80S.

MODELS IN BETTER AGREEMENT IN MOVG S/W ENERGY NE ALONG THE STALLED
BNDRY THURS NIGHT THRU ERLY FRIDAY BEFORE HIGH PRESSURE BUILDS IN
FROM THE NORTH FRI NIGHT. GIVEN THIS TREND...INCREASED BOTH CLOUD
COVERAGE AND POPS FOR THIS PRD. SLOW MOVG...TRAINING ECHOES COULD
PRODUCE LCLLY HVY DOWNPOURS ACROSS ESPECIALLY THE SERN HALF OF FA
THUS QPF HAS BEEN SIGNIFICANTLY RAISED. LOWS THU NIGHT M60S-L70S.
HIGHS FRI M-U80S.

TOTAL QPF THRU FRIDAY WILL VARY FROM BTWN 1/4 TO 1/2 INCH ACROSS
NWRN CNTYS...1/2 TO 1 INCH ACROSS CNTRL SCTNS OF FA TO BTWN 1-2
INCHES ACROSS SERN VA...2+ INCHES PSBL ACROSS NERN NC.

GENLY DRIER SAT AS THE FRONT WASHES OUT BUT WILL KEEP A 20-30%
POP OVER THE FAR NW AND IN SE VA/NE NC. PARTLY SUNNY WITH HIGHS IN
THE 80S.

&&

.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
AMPLIFIED UPPER FLOW OVER THE HIGHER LATITUDES WILL PUSH ANOTHER
ANOMALOUS TROUGH INTO THE NERN CONUS EARLY NEXT WEEK. THE RESULT
WILL BE BELOW NORMAL TEMPS AND WET CONDITIONS FROM THE UPPER MIDWEST
TO THE OH VALLEY. HOWEVER...THE LOCAL AREA REMAINS SEASONABLY WARM
AS MUCH OF THE COOLER AIR WILL BE LOCKED WEST OF THE CNTRL
APPALACHIANS.

FOR THE LATTER HALF OF THE WEEKEND...ONGOING RETURN FLOW ON THE
BACKSIDE OF HIGH PRESSURE ANCHORED OVER THE WRN ATLANTIC WILL RESULT
IN SLIGHTLY WARMER TEMPS AND DEWPOINTS SUN COMPARED TO SAT.
THICKNESSES YIELD TEMPS RIGHT AROUND 90 DEGS. A COLD FRONT WILL PUSH
INTO THE GREAT LAKES REGION SUN WITH SFC TROUGHING DEVELOPING OVER
THE LOCAL AREA. THETA-E ADVECTION AND A MOIST BL WILL RESULT IN
MLCAPE VALUES ~1500 J/KG. MODEL DERIVED PRECIP WATERS RANGE FROM
1.75 TO 2 INCHES. WHILE MOISTURE/INSTABILITY LOOK FAVORABLE...BEST
DYNAMICS/FORCING REMAINS WELL WEST OF THE AREA WITH THE BETTER
HEIGHT FALLS AND STRONGER WINDS ALOFT. SHEAR IS ALSO UNIMPRESSIVE
AND SOUNDINGS DEPICT SUBSIDENCE/WARM AIR ALOFT. WILL CARRY CHANCE
POPS IN THE NW...TAPERING OFF TO SILENT IN THE SE. BETTER COVERAGE
EXPECTED MON AS HEIGHT FALLS AND INCREASING WINDS ALOFT PROVIDE
BETTER FORCING FOR ASCENT AND COOLER MID-LEVEL TEMPS. COLD FRONT IS
EXPECTED TO REACH THE CNTRL APPALACHIANS LATE MON...SHARPENING THE
THERMAL TROUGH OVER THE LOCAL AREA. WARMER TEMPS AND DEWPOINTS WILL
PUSH MLCAPE VALUES HIGHER...BUT SHEAR REMAINS MARGINAL (AOB 20 KT).
THE RESULT WILL BE SCT AFTERNOON SHOWERS/THUNDERSTORMS ACROSS MUCH
OF THE REGION. COLD FRONT DROPS INTO THE REGION TUES-TUES NIGHT.
EXACT TIMING OF THE FRONT WILL IMPACT SENSIBLE WEATHER OVER THE
LOCAL AREA. WILL TREND TOWARD A BLEND BTWN THE MEDIUM RANGE
GUIDANCE...KEEPING THE BEST POPS ALONG THE COAST TUES. BASED ON THE
AIRMASS...WILL ALSO CARRY SLIGHT CHANCE POPS MON NIGHT-TUES MORNING
AS THE FRONT CROSS THE REGION. UPPER LOW BEGINS TO EJECT FROM THE
GREAT LAKES REGION TUES INTO SE CANADA...SLOWING THE FRONT AS IT
PUSHES OFFSHORE TUES NIGHT-WEDS MORNING. CONFIDENCE IS NOT HIGH
ATTM...BUT WILL HANG ON TO SLIGHT CHANCE POPS ALONG THE COAST WEDS
BASED ON THE FRONT LIKELY STALLING OFFSHORE.

TEMPS WILL REMAIN AROUND SEASONABLE NORMS...WARMING INTO THE UPPER
80S-LOW 90S THRU THE PERIOD. ANTICIPATE TUES TO BE THE WARMEST IN
ADVANCE OF THE FRONT...WITH HIGHS GENERALLY IN THE LOW 90S.
OVERNIGHT LOWS WILL GENERALLY BE IN THE UPPER 60S-LOW 70S...WITH MID
70S NEAR THE COAST.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
SHOWERS OVER SE VA AND NE NC ARE GRADUALLY DISSIPATING BUT COULD
BRING MVFR CIGS AND VSBY TO TERMINAL IN THAT AREA THROUGH 08Z.
UPPER TROF CONTINUES ACROSS THE AREA TODAY. THERE WILL BE SEVERAL
BOUNDARIES ACROSS THE AREA WHICH COULD FOCUS CONVECTION THIS
AFTERNOON INTO TONIGHT. ALL MODELS AGREE ON CONVECTION DEVELOPING
JUST NOT SURE WHETHER TO THE WEST MOSTLY RECEIVES IT OR BACK
ACROSS THE SOUTHEAST. FOR THAT REASON DID NOT PUT A TEMPO GROUP IN
FOR TSTMS AT THIS TIME. HOWEVER THINK MOST AREAS WILL GO TO MVFR
OR EVEN IFR IN TSTMS SOMETIME THIS AFTERNOON OR TONIGHT. WITH
DIMINISHING FLOW BY TONIGHT ANY THUNDERSTORMS THAT DO FORM WILL BE
SLOW TO MOVE. OUTSIDE OF THE PRECIPITATION EXPECT VFR CONDITIONS
WITH SOME CLOUDS AROUND 10 THOUSAND FEET.

FRONT CROSSES AREA BY FRIDAY...LEAVING FRI NGT/SAT DRY ATTM. NEXT
FRONT COULD BRING THE POTENTIAL FOR MORE SHWRS/TSTMS TO THE REGION
LATE SUNDAY OR MONDAY.

&&

.MARINE...
SUB-SCA CONDITIONS OVER THE WATERS THIS AFTERNOON WITH S-SW WINDS
GENERALLY AROUND 10 KT...WAVES 1-2 FT AND SEAS 2 TO 3 FT. HIGHER
WAVES OBSERVED IN THE NRN COASTAL WATERS...REACHING 4 FT 20 NM OUT.
A FRONTAL BOUNDARY WILL DISSIPATE OVER THE WATERS THIS
AFTERNOON/EVENING AS ANOTHER FRONT APPROACHES THE REGION
TONIGHT...STALLING OVER THE REGION THURS. HIGH PRESSURE BUILDS INTO
THE NE STATES THURS...REMAINING OVER NEW ENGLAND THRU FRI NIGHT. THE
RESULT WILL BE NELY FLOW OVER THE WATERS THUR-FRI...REMAINING SUB
SCA AT 10 KT OR LESS. HIGH PRESSURE PUSHES OFF THE NE COAST SAT INTO
SUN...PHASING WITH SFC HIGH PRESSURE OVER THE WRN ATLANTIC. FLOW
VEERS TO THE SOUTH SUN...REMAINING SUB SCA AT 10-15 KT. SEAS REMAIN
2-3 FT. LOW PRESSURE LIFTS INTO THE GREAT LAKES REGION MON AS A COLD
FRONT PUSHES INTO THE OH VALLEY. GRADIENT WILL STRENGTHEN SLIGHTLY
OVER THE WATERS SUN NIGHT-MON...BUT REMAINS SUB-SCA. PERSISTENT SLY
FLOW WILL PUSH SEAS TO 4 FT IN THE NRN WATERS...BUT ANTICIPATE SEAS
TO REMAIN UNDER 5 FT. COLD FRONT CROSSES THE WATERS TUES NIGHT-WED
MORNING.

&&

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

&&

$$
SYNOPSIS...LKB
NEAR TERM...LKB/MAM
SHORT TERM...LKB/MPR
LONG TERM...SAM
AVIATION...JAB/WRS
MARINE...SAM