Special Weather Statement, NWS Blacksburg, VA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
150 PM EDT THU AUG 2 2012

.SYNOPSIS...
UPPER LEVEL HIGH PRESSURE WILL EXPAND OVER THE SOUTHEAST AND THE
MIDDLE ATLANTIC THROUGH THE WEEKEND. A COLD FRONT WILL DROP SOUTH
FROM THE GREAT LAKES AND THE OHIO VALLEY EARLY NEXT WEEK.

&&

.NEAR TERM /UNTIL 8 PM THIS EVENING/...
AS OF 127 PM EDT THURSDAY...

SUBTLE THETA E ADVECTION OVER THE PAST FEW HOURS INTO THE EXTREME
SE CWA...IS WORTHY OF A SLIGHT INCREASE FOR POPS THERE THIS
AFTERNOON.

AS OF 1023 AM EDT THURSDAY...

REALLY LACKING A TRIGGER TODAY IN COMPARISON TO YESTERDAY.
EXPECTING LESS COVERAGE THAN WEDNESDAY. OF COURSE...AS ALWAYS...IF
ONE STORM IS ABLE TO FORM AND GENERATE A STRONG ENOUGH OUTFLOW
THEN STORMS MAY BECOME MORE NUMEROUS...BUT THAT IS NOT EXPECTED TO
HAPPEN. WILL HAVE TO RELY ON GENERIC ELEVATED CONVECTION ALONG THE
HIGHEST ELEVATIONS FOR STORMS TO DEVELOP. BASED UPON YESTERDAY'S
HIGHS DID RAISE MAX T A FEW DEGREES ACROSS THE SOUTHSIDE AND PIEDMONT
TODAY.

AS OF 430 AM THURSDAY...

UPPER LEVEL DISTURBANCE WHICH MOVED THROUGH THE SOUTHERN CWA LAST
NIGHT WILL MOVE AWAY FROM THE AREA THIS MORNING. A BROAD UPPER
LEVEL TROUGH WILL REMAIN...BUT IS FORECAST TO FILL WITH TIME AS
HEIGHTS BUILD OVER THE MID ATLANTIC REGION. AT THE SURFACE...WEAK
BUBBLE OF HIGH PRESSURE WILL PASS OVHD. MODEL SOUNDINGS INDICATE
DRYING WILL TAKE PLACE ALOFT. HOWEVER...IT DOES NOT LOOK LIKE
THERE WILL BE ENOUGH SUBSIDENCE TO TOTALLY NEGATE DEEP CONVECTION
THIS AFTERNOON. FCST CAPES OF AROUND 1500 ARE FCST...THUS THINK
POTENTIAL EXISTS FOR AT LEAST ISOLATED COVERAGE THIS
AFTERNOON...POPS/COVERAGE GENERALLY UNDER 20 PERCENT. ANYTHING
THAT MANAGES TO DEVELOP WILL BE SLOW MOVING...MEAN WIND OF 10 KTS
OR LESS.

WITH H85 TEMPS REACHING +20C...LOOKS LIKE A TOASTY
AFTERNOON...HIGHS RANGING FROM THE 80S MOUNTAINS TO THE L-M90S
SOUTHSIDE AND PIEDMONT. LOWS TONIGHT LOOK MILD WITH READINGS
MAINLY IN THE 60S...AROUND 70 IN THE BURBS OF ROA/LYH/DAN.

&&

.SHORT TERM /8 PM THIS EVENING THROUGH SATURDAY/...
AS OF 400 AM EDT THURSDAY...

5H HEIGHTS PEAK FRIDAY...THEN START TO BREAK DOWN THIS
WEEKEND...THE SURFACE HIGH SLIDING OFFSHORE...WEAK IMPULSES
ROUNDING THE UPPER RIDGE TO OUR WEST. THIS ALONG WITH WEAK RETURN
FLOW AND INCREASING PWATS WILL BRING INCREASING THREAT OF
SHRA/TSRA BACK BY FRIDAY AFTERNOON...AND EVEN MORE SO OVER THE
WEEKEND. POPS WILL BE HIGHEST OVER THE MTNS FRIDAY COMPARED TO THE
PIEDMONT...BUT ALMOST EQUAL CHANCES ANTICIPATED AREA WIDE
SATURDAY.

PATTERN THIS WEEKEND IS FORECAST TO EVOLVE BACK TO A HIGHER AMPLITUDE
TROF IN THE EASTERN CONUS WITH MODELS INDICATING A BETTER
SHORTWAVE HEADING INTO THE MOUNTAINS BY SAT AFTERNOON. THIS
COMBINED WITH HEATING AND MOISTURE MAY MAKE FOR MORE ORGANIZED
STORM COVERAGE ESPCLY BLUE RIDGE WEST WHERE MAY NEED TO INCREASE
POPS ABOVE WHAT WE HAVE ADVERTISED NOW...SOME OF THE MODEL MOS
SUGGESTING 60/70 PERCENT PROBABILITIES.

WARM THICKNESSES AND +20 DEG C 85H TEMPS SUPPORT HOT TEMPS FRIDAY
WITH HIGHS PUSHING THE LOW/MID 90S EAST AND UPPER 80S MOUNTAINS.
SHOULD BE SLIGHTLY COOLER ALTHOUGH STILL MUGGY GIVEN MORE
CLOUDS/SHRA SATURDAY AFTERNOON WHICH MAY KEEP HIGHS A BIT LOWER
OVER THE WEST BUT STILL 90ISH SE. TMINS REMAIN MILD WITH READINGS
IN THE 60S TO L70S.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
AS OF 115 PM EDT WEDNESDAY...

TROFFINESS WILL LINGER ACROSS THE REGION FOR THE LAST PART OF THE
WEEKEND WITH DEEPER MOISTURE IN PLACE SUNDAY AHEAD OF A STRONGER
SHORTWAVE TROF APPROACHING FROM THE NW. THIS SHOULD RESULT IN A
ANOTHER ROUND OF SCATTERED SHRA/TSRA SAT EVENING AND AGAIN SUNDAY
AFTERNOON ESPCLY MOUNTAINS WHERE WILL BE CLOSER TO THE UPSTREAM
SURFACE COLD FRONT...AND WITHIN THE PRECEDING DEEPER SW TO NE
MOISTURE LOBE. THIS FRONT LOOKS TO PUSH SE TOWARD THE AREA MONDAY
BEFORE EITHER STALLING NEARBY OR PERHAPS LIMPING THROUGH BY
TUESDAY MORNING AS THE 5H TROF LIFTS OUT TO THE NE. THUS LIKE
SLOWER PROGRESSION OF THE BOUNDARY ALLOWING PRE-FRONTAL OUTFLOW TO
INTERACT WITH HEATING/MOISTURE FOR BETTER COVERAGE OF STORMS
MONDAY AFTERNOON/EVENING. CONVECTIVE LINE MAY TAKE THE FRONT TO
THE SE MONDAY NIGHT RESULTING IN SOME DRYING ESPCLY NORTH AND WEST
TUESDAY INTO WEDNESDAY BUT QUITE UNCERTAIN AT THIS POINT.
THEREFORE KEEPING SOME LOW POPS SOUTHEAST BOTH DAYS AND ISOLATED
CHANCES WESTERN RIDGES WEDNESDAY AFTERNOON FOR WEAK RETURN FLOW
POP UP STORMS. OTRW TEMPS RATHER CLOSE TO IF NOT A BIT ABOVE
NORMAL...WITH HIGHS MAINLY 80S EXCEPT AROUND 90 SE THRU THE
PERIOD.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
AS OF 144 PM EDT THURSDAY...

STORMS TO REMAIN WIDELY SCATTERED THIS PM AND OVERNIGHT. BEST CHC
FOR ANYTHING TO IMPACT AN AIRPORT WOULD BE KDAN LATER THIS
AFTERNOON...AS BEST INSTABILITY RESIDES JUST SOUTH OF THE VA
BORDER WITH STORMS POSSIBLE MOVING NNE INTO THE REGION. IF IT DOES
RAIN AT KDAN THIS PM THEN IFR VIS/CIG WILL BE MORE LIKELY. DRIER
PROFILE TODAY SHOULD KEEP IFR CIG/VIS RESERVED TO KLWB ONCE AGAIN
TONIGHT...ALTHOUGH CURRENT DEWPOINT OF 54F SUGGESTS LAMP GUIDANCE
IS BEING TOO PESSIMISTIC WITH REGARDS TO IFR DURATION THERE
TONIGHT.

12Z MODELS HAVE EMPHASIZED A SHRTWV MOVING INTO WEST VA AND E KY
LATE FRIDAY. THIS MAY PRODUCE NUMEROUS STORMS FOR KBLF BY LATE
DAY...ALTHOUGH THAT IS OUTSIDE THE TAF PERIOD CURRENTLY. SOME OF
THESE CELLS MAY BE STRONG ENOUGH TO PRODUCE BRIEF IFR CONDS. SOME
OF THESE STORMS MAY SURVIVE INTO KLWB/KBCB/KROA AFTER DINNERTIME
FRIDAY. OTHERWISE A THREAT FOR POP UP SCATTERED CONVECTION WILL BE
THE ONLY OPPORTUNITY FOR RESTRICTIONS AT THESE TERMINALS FRIDAY AND FRIDAY
NIGHT.

DEEPER MOISTURE WILL BEGIN TO RETURN OVER THE WEEKEND WITH
GREATER COVERAGE OF SHOWERS AND STORMS...ESP DURING THE AFTERNOON
AND EVENING. LOCAL MVFR/IFR CONDITIONS WILL BE ASSOCIATED WITH
THE STORM ACTIVITY WITH ORGANIZED ACTIVITY POSSIBLE EACH DAY FROM
SATURDAY THROUGH MONDAY. OUTSIDE OF THIS MAINLY DIURNALLY DRIVEN
CONVECTION...THE ONLY OTHER FLIGHT WEATHER HAZARDS WOULD BE FROM
OVERNIGHT VALLEY FOG.

A COLD FRONT IS EXPECTED TO DROP SOUTHEAST OUT OF THE OHIO VALLEY
MONDAY...CROSSING THE MID ATLANTIC REGION. WITH THE PASSAGE OF
THIS FRONT...WINDS SHOULD BECOME NORTHERLY...WITH A DAY OR TWO OF
DRY WEATHER FOLLOWING THE FRONTAL PASSAGE FOR TUESDAY AND
WEDNESDAY.

&&

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

&&

SYNOPSIS...PM
NEAR TERM...KM/PM
SHORT TERM...JH/PM
LONG TERM...JH
AVIATION...KM/PM

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BLACKSBURG VA
503 AM EDT THU AUG 2 2012

NCZ001>006-018>020-VAZ007-009>020-022>024-032>035-043>047-058-059-
WVZ042>045-030915-
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-
503 AM EDT THU AUG 2 2012

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.

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

POTENTIAL EXISTS FOR STRONG TO SEVERE STORMS THIS WEEKEND...THREAT
MAINLY DURING THE LATE AFTERNOON AND EARLY EVENING. THUNDERSTORMS
ARE POSSIBLE EACH DAY FROM FRIDAY THROUGH MONDAY.  THE PROBABILITY
FOR WIDESPREAD HAZARDOUS WEATHER IS LOW FRIDAY...BUT WILL INCREASE
OVER THE WEEKEND...PARTICULARLY MORE SO FOR SUNDAY AND MONDAY
AS A COLD FRONT CROSSES THE REGION.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BLACKSBURG VA
902 AM EDT THU AUG 02 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1208 AM     HAIL             2 NNE GLENDALE SPRINGS  36.37N 81.37W
08/02/2012  E1.00 INCH       ASHE               NC   PUBLIC

            HAIL OF VARIOUS SIZES OCCURRED FOR NEARLY ONE HOUR ENDING
            AROUND 1245 AM EDT...AND ACCUMULATED TO A DEPTH OF ONE TO
            TWO INCHES IN SOME AREAS.

&&

WERT

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BLACKSBURG VA
1003 AM EDT THU AUG 02 2012

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0152 AM     HAIL             2 SE FRANCISCO          36.48N 80.35W
08/02/2012  E1.00 INCH       STOKES             NC   PUBLIC

            QUARTER SIZE HAIL LASTED FOR ABOUT 15 MINUTES

&&

PW

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BLACKSBURG VA
230 PM EDT THU AUG 2 2012

VAZ045-021900-
CAMPBELL VA-
230 PM EDT THU AUG 2 2012

...A STRONG THUNDERSTORM WILL AFFECT CAMPBELL COUNTY...

AT 228 PM EDT...A STRONG THUNDERSTORM WAS LOCATED 9 MILES NORTHWEST
OF BROOKNEAL...MOVING EAST AT 5 MPH.

WIND GUSTS TO 30 MPH ARE POSSIBLE WITH THIS STORM. VERY HEAVY RAIN
WILL FALL FROM THIS STORM...AND WILL CAUSE WATER TO POND ON ROADS AND
QUICKLY FILL ROADSIDE DITCHES AND SMALL STREAMS.

THIS STORM WILL BE NEAR GLADYS AROUND 235 PM...GLADYS AROUND 240 PM
AND HAT CREEK AROUND 300 PM.

FOR ADDITIONAL WEATHER INFORMATION...VISIT US ON THE WEB AT
HTTP://WEATHER.GOV.

LAT...LON 3703 7894 3705 7897 3704 7899 3707 7911
      3709 7912 3708 7914 3708 7915 3719 7915
      3724 7891 3703 7890

AMS