Severe Thunderstorm Warning 117, NWS Blacksburg, VA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
331 PM EDT WED JUN 13 2007

.SYNOPSIS...
A STRONGER UPPER AIR DISTURBANCE WILL MOVE INTO THE BLUE RIDGE BY
LATE THURSDAY. COOLER AIR WILL SINK INTO THE BLUE RIDGE AS HIGH
PRESURE INTENSIFIES OVER THE MIDDLE ATLANTIC. AN UPPER RIDGE WILL
ARRIVE FROM THE MISSISSIPPI RIVER VALLEY NEXT WEEK.

&&

.NEAR TERM /THROUGH THURSDAY/...
ENERGY IN THE NORTHERN FLOW ALOFT IS RATHER WEAK THIS
AFTERNOON...HOWEVER THERE IS ENOUGH DIFFERENTIAL HEATING ON THE
RIDGES TO FIRE UP CONVECTION IN THE WEST. COVERAGE SHOULD CONTINUE
TO EXPAND THRU MID-AFTERNOON WITH A FEW ISOLATED SEVERE STORMS OR
FLOODING STILL POSSIBLE...THEN SLOWLY DIMINISH THIS EVENING WITH
LOSS OF HTG. MEANWHILE...A MARITIME AIRMASS PUSHING ONSHORE ACROSS
NEW JERSEY AND THE DELMARVA PENINSULA...WILL MOVE INTO EASTERN
PORTIONS OF THE CWA TONIGHT...POSSIBLY PRECEDED BY ANOTHER AREA OF
SHOWERS AND STORMS. THIS NOTICEABLY COOLER...MORE STABLE AIRMASS
WILL PUSH EAST ACROSS THE NORTHEASTERN 2/3RDS OF THE CWA WHILE IN
THE FAR SOUTHWEST...DESTABILIZATION AND TSTMS WILL BE LIKELY BY
AFTERNOON...WITH ENHANCEMENT OF CONVECTION LIKELY DUE TO A STRONG
SHORTWAVE DROPPING SOUTH THRU THE MID-ATLANTIC.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
NAM/GFS/SREF ALL POINT TO MORE NUMEROUS SHWRS AND STORMS WITH THE
ARRIVAL OF A POTENT SHRTWV FROM THE NORTH LATE THURSDAY. HIGH
PRESSURE BUILDING INTO THE MIDDLE ATLANTIC INTO FRIDAY
MORNING...WILL ALLOW FOR COOL AIR DAMMING AND EASTERLY FLOW
AGAINST THE ELEVATIONS. THUS...TOOK THUNDER OUT OF WX GRIDS
THROUGH FRIDAY...WITH LOSS OF INSTABILITY. KEPT AT LEAST LIKELY
POPS IN HIGHEST SW ELEVATIONS ALSO THROUGH MUCH OF FRIDAY.
CONTINUED TREND OF LOWERING MAX T GRID...USING 2M NAM TEMPS AS A
BASE...THEN ADJUSTING FROM THERE. SPOTS ALONG THE BLUE RIDGE AND
WEST WILL STRUGGLE TO 70F FOR HIGHS. THIS REGIME WILL LAST THROUGH
FRIDAY NIGHT UNTIL...H5 HEIGHTS INC FROM WEST TO EAST THROUGH THE
WEEKEND.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
ONE LAST SHRTWV ROTATES AROUND VORTEX OFF THE NEW ENGLAND COAST...BUT
THIS TIME HAS LITTLE CAPE TO WORK WITH AFTER ATMS WAS STABILIZED
ON FRIDAY. MIGHT BE ENOUGH OF A SOUTHERLY COMPONENT OFF THE
ATLANTIC TO ALLOW SOME SHWRS TO FORM IN MY EXTREME SE CORNER...BUT
POPS WERE LEFT OUT FRO NOW ON SATURDAY. THIS MAY NEED TO BE
CONSIDERED..BASED UPON MODEL PROGGING THESE SHRTWVS A LITTLE TOO
FAR EAST THIS WEEK. DID FOLLOW WARMER ECMWF H85 TEMPS SUNDAY AND
ONWARD...AS OP GFS AND ENSEMBLE NUMBERS HAVE BEEN CHASING THE
EUROPEAN MODEL ALL WEEK. THUS...DID GO A FEW DEGREES ABOVE MEX
TEMPS SUNDAY ONWARD. EXPECTING MID 90S TO RETURN TO THE PIEDMONT
AHEAD OF A WEAK FRONT TUESDAY NEXT WEEK. POPS WERE INSERTED INTO
THE FORECAST LATE TUESDAY IN THE WEST...AS THE BOUNDARY WILL PROB
STALL IN WESTERN VIRGINIA AS MOST OF ITS SUPPORT PASSES INTO SE
CANADA.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
SCTD TO NUMEROUS SHOWERS AND TSTMS WILL BE AROUND THROUGH EARLY
EVENING...THEN A GRADUAL DIMINISHING OF ACTIVITY. A MARITIME AIRMASS
APPROACHES FROM THE NORTHEAST OVERNIGHT AND WILL BRING MORE STABLE
AIR TO THE EASTERN SITES (ROA/LYH/DAN) THURSDAY. AHEAD OF THIS
BNDRY SHOWERS AND MVFR CIGS/VSBYS ARE LIKELY WITH MVFR CONDITIONS
PERSISTING THROUGH EARLY AFTERNOON IN THE EAST. BLF WILL BE WEST
OF THE BNDRY THURSDAY AND WILL STAND THE BEST CHANCE OF VFR
CONDITIONS BEFORE ANY AFTERNOON CONVECTION.

LIGHT EAST/SOUTHEASTERLY FLOW WILL CONTINUE INTO SATURDAY IN THE
EAST SO THE CHANCE OF OFF AND ON MVFR CIGS AND VSBYS WILL BE
HIGHER THAN CLIMATOLOGY THRU THE PD. CHANCE OF LATE DAY CONVECTION
WILL MAINLY BE IN THE FAR WEST ON THE EDGE OF THE DECAYING
MARITIME AIRMASS.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...NONE.
NC...NONE.
WV...NONE.

&&

SYNOPSIS...KM
NEAR TERM...JS
SHORT TERM...KM
LONG TERM...KM
AVIATION...JS

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BLACKSBURG VA
450 AM EDT WED JUN 13 2007

NCZ001>006-018>020-VAZ007-009>020-022>024-032>035-043>047-058-059-
WVZ042>045-140900-
ASHE-ALLEGHANY NC-SURRY-STOKES-ROCKINGHAM-CASWELL-WATAUGA-WILKES-
YADKIN-TAZEWELL-SMYTH-BLAND-GILES-WYTHE-PULASKI-MONTGOMERY-GRAYSON-
CARROLL-FLOYD-CRAIG-ALLEGHANY VA-BATH-ROANOKE-BOTETOURT-ROCKBRIDGE-
PATRICK-FRANKLIN-BEDFORD-AMHERST-HENRY-PITTSYLVANIA-CAMPBELL-
APPOMATTOX-BUCKINGHAM-HALIFAX-CHARLOTTE-MERCER-SUMMERS-MONROE-
GREENBRIER-
450 AM EDT WED JUN 13 2007

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL NORTH
CAROLINA...NORTHWEST NORTH CAROLINA...CENTRAL VIRGINIA...SOUTH
CENTRAL VIRGINIA...SOUTHWEST VIRGINIA...WEST CENTRAL VIRGINIA AND
SOUTHEAST WEST VIRGINIA.

.DAY ONE...TODAY AND TONIGHT

NUMEROUS SHOWERS AND THUNDERSTORMS ARE EXPECTED THIS AFTERNOON AND
EVENING. THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE
AREA. DAMAGING WIND GUSTS AND LARGE HAIL ARE THE PRIMARY THREATS.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON OR EVENING.