Severe Thunderstorm Warning 246, NWS Wakefield, VA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE WAKEFIELD VA
424 PM EDT WED JUL 30 2008

.SYNOPSIS...
AN UPPER LEVEL LOW WILL REMAIN CENTERED NEAR THE GREAT LAKES
THROUGH THE WEEKEND. SEVERAL WEAK FRONTS WILL ROTATE AROUND THE LOW
AND THROUGH THE REGION THROUGH EARLY SUNDAY. HIGH PRESSURE WILL START
TO BUILD IN BY LATE SUNDAY...AND WILL THEN HOLD IN PLACE OVER THE
REGION THROUGH EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 2 AM THURSDAY MORNING/...
AN EXTENSIVE CU FIELD HAS DEVELOPED ALONG A PIEDMONT TROF WHICH IS
CURRENTLY DRAPED ACROSS VIRGINIA. A FEW ISOLATED SHOWERS AND
THUNDERSTORMS HAVE ALREADY FORMED EARLY THIS AFTERNOON...AND
EXPECT TO SEE AN INCREASE IN COVERAGE AND INTENSITY LATER THIS
AFTERNOON AND EVENING AS THE CAPPING INVERSION DIMINISHES.
VERTICAL SHEAR IS ALSO EVIDENT ON LOCAL RADARS...WITH 40 TO 50 KT
BARBS OVER OUR AREA. A MOIST AIRMASS REMAINS IN PLACE WITH SFC OBS
REPORTING DEW POINTS IN THE LWR/MID 70S. IN ADDITION...MODEL BUFR
SOUNDINGS DIAGNOSE CAPES OF 2000-3000 J/KG ACROSS THE AREA. SPC
HAS ACCORDINGLY PLACED MUCH OF OUR FA IN A SLIGHT RISK FOR SEVERE
WEATHER...WITH THE GREATEST THREATS BEING DAMAGING WINDS AND LARGE
HAIL. NO CONVECTIVE WATCH HAS BEEN ISSUED YET...ALTHOUGH ONE IS
LIKELY TO BE ISSUED WITHIN THE NEXT FEW HOURS.

THE SEVERE THREAT WILL DIMINISH AFTER SUNSET AS THE AIRMASS
BECOMES MORE STABLE WITH THE LOSS OF DAYTIME HEATING...AND AS THE
SFC TROF MOVES OFFSHORE. KEPT 30% POPS ALONG SE VA/NE NC EXTENDING
UP TO THE ERN SHORE FOR ANY LINGERING ACTIVITY...WITH ONLY A
SLIGHT CHANCE OF SHRAS FOR ALL OTHER AREAS AFTER MIDNIGHT. ANOTHER
MILD AND MUGGY NIGHT TONIGHT...WITH LOW TEMPERATURES BOTTOMING
OUT BETWEEN 70 AND 75. PATCHY FOG WILL AGAIN BE LIKELY OVER THE
ERN SHORE AND ALSO IN ANY AREAS THAT DO MANAGE TO SEE PRECIPITATION.

&&

.SHORT TERM /2 AM THURSDAY MORNING THROUGH SATURDAY/...
THE UPPER LEVEL LOW THAT HAS BEEN PARKED NEAR THE GREAT LAKES WILL
REMAIN CENTERED TO OUR NORTH THROUGH THIS WEEKEND. THE DAILY TROFS
WILL CONTINUE TO ROTATE THROUGH OUR REGION AROUND THE UPPER LOW.
THE NEXT TROF WILL MOVE THROUGH THE REGION ON THURSDAY WITH
CONTINUING INSTABILITY EXPECTED IN THE AFTERNOON AND EVENING
HOURS. SPC HAS AGAIN PUT OUR SRN COUNTIES IN A SLIGHT RISK FOR
SEVERE WEATHER. MAX TEMPS WILL CONTINUE TO BE HOT...AND WILL
RANGE FROM 90 TO 95 ON THURSDAY THROUGH SATURDAY. AS IS TYPICAL FOR
THIS TIME OF YEAR...SCATTERED SHOWERS AND THUNDERSTORMS WILL BE
POSSIBLE EACH AFTERNOON AND EVENING DURING PEAK HEATING HOURS. LOW
TEMPERATURES REMAIN MILD...70 TO 75.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
TROUGH ALOFT TRENDING A BIT SLOER IN SWINGING THROUGH NE QTR OF
CONUS LT WKND...DELAYING ARRIVAL OF HEAT DOME FM THE W. HV TRIMMED
TEMPS ABT 5 DEGS F FOR SUN...AS WELL AS BRINGING DRYING/LWR DWPTS
INTO THE RGN FOR A BRIEF SPELL INTO MON. HI TEMPS SUN MID 80S (NNE
SXNS) TO MID 90S (FAR INTR SRN AREAS). HWVR...RDG ALOFT EVENTUALLY
BUILDS STRNGLY EWD TWD/INTO MDATLC RGN BY TUE/WED NEXT WK...BRINGING
HEAT AND GRDL INCRS TO HUMIDITY. WDSPRD HI TEMPS IN THE (MID/UPR)
90S - EVEN PSBL 100 INTR) TUE/WED. NEXT CDFNT APPROACHES FM NNW LT
NEXT WK.

&&

.AVIATION /21Z WEDNESDAY THROUGH MONDAY/...
A COUPLE OF ISOL CELLS HAVE DEVELOPED OV SE VA. MORE WDSPR
ACTIVITY OCCURRING OV WRN PA ASSOC WITH PVA THAT WILL SPREAD ACRS
NRN PORTIONS OF OUR AREA LATER THIS AFTN. PUT CB REMARKS AFT
19/20Z. CONDS SIMILAR TO THIS MORNING ARE INDICATED FOR THURSDAY
MORNING WITH LIFR EXPECTED AT SBY. HIGH PRESSURE BUILDS IN TOWARD
THE WEEKEND WITH SOME SCT AFTN TS MAINLY THU AND FRI.

&&

.MARINE...
WK LVL BNDRY LINGERS OVR NRN WTRS THIS AFTN/EVE...B4 DSPTG OVRNGT.
LLVL FLO FM THE ESE INVOF/N OF THAT BNDRY INTO THIS EVE...OTRW ALL
AREAS WL HV WND DRCTN TURN TO THE WSW. FNTL BNDRY FM THE NW
APPROACHES THU...WL LLVL FLO RMNG FM THE SW (HIEST SPDS RMNG AOB 15
KT). WNDSHFT TO THE NNW IN WAKE OF FNT DURG FRI (MAY BE A BRIEF/VRY
SHORT PD OF ENHANCED SPDS TO 10-15 KT W/ OR RIGHT BEHIND FNTL
PASSAGE ERY FRI). AHD OF 2ND FNT...LLVL FLO SW XPCTD ON
SAT...SHIFTING TO NW SAT NGT/SUN. CONTD NO SCAS UFN.

&&

.EQUIPMENT...
KAKQ RADAR IS LIMITED TO LONG PULSE OPERATIONS (VCP 31) THROUGH
THIS EVENING UNTIL A PART ARRIVES THAT WILL ALLOW FOR SHORT AND
LONG PULSE OPERATIONS TO RESUME.

&&

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

&&

SYNOPSIS...JRL
NEAR TERM...JRL
SHORT TERM...JRL
LONG TERM...ALB
AVIATION...LSA
MARINE...ALB
EQUIPMENT...BAJ