Special Weather Statement, NWS Blacksburg, VA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
351 PM EDT SAT JUL 30 2011

.SYNOPSIS...
A FRONTAL BOUNDARY WILL REMAIN OVER THE AREA THROUGH SUNDAY NIGHT
AND BE THE FOCUS FOR SCATTERED SHOWERS AND STORMS. HIGH PRESSURE
WILL BRING DRY WEATHER BACK TO THE REGION MONDAY THROUGH
WEDNESDAY. ON FRIDAY...ANOTHER COLD FRONT WILL MOVE ACROSS THE
AREA ALONG WITH SCATTERED SHOWERS AND STORMS.

&&

.NEAR TERM /THROUGH SUNDAY/...
AS OF 1930Z...330 PM EDT...THE SURFACE COLD FRONT IS SOUTH OF THE
AREA. THE 850 MB COLD FRONT IS ACROSS THE WESTERN AND NORTHERN PARTS
OF THE REGION. CLUSTERED SCATTERED SHOWERS AND STORMS HAVE DEVELOPED
ALONG THIS BOUNDARY. WE ARE ANTICIPATING THE 850 MB FRONT TO SAG
FARTHER SOUTH TONIGHT TO NEAR THE VA/NC BORDER. ANTICIPATE
ADDITIONAL SHOWERS AND STORMS TO EXIST ALONG AND NEAR IT HEADING
INTO THE EVENING HOURS. WE DO NOT EXPECT PRECIPITATION TO END
OVERNIGHT...BUT REMAIN SCATTERED ALONG THIS BOUNDARY THROUGH THE
OVERNIGHT HOURS. HOWEVER...THE FREQUENCY OF THUNDERSTORMS IS
EXPECTED TO WANE. LOW LEVELS WINDS WILL GRADUALLY VEER NORTHEAST AS
THE NIGHT PROGRESSES...AND WE ARE EXPECTING A MOSTLY CLOUDY TO
CLOUDY SKY ACROSS THE REGION TO DEVELOP AS LOW LEVEL MOISTURE POOLS
ALONG AND OVER THE MOUNTAINS.

ON SUNDAY...CLOUDS WILL LINGER THROUGH THE DAY AS THE 850 MB FRONT
HOLDS FAST NEAR THE VA/NC BORDER. SHOWERS AND STORMS WILL BE FOCUSED
NEAR THIS BOUNDARY THROUGH THE DAY...WITH THE BEST COVERAGE IN THE
AFTERNOON WHEN INSTABILITY ALOFT WILL BE AT ITS GREATEST. THE CLOUD
COVER WILL HELP KEEP TEMPERATURES A LITTLE COOLER THAN IN RECENT
DAYS. LOW TO MID 80S WILL BE COMMON IN THE MOUNTAINS WITH MID TO
UPPER 80S EAST OF THE BLUE RIDGE.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AT THE BEGINNING OF THE SHORT TERM PERIOD...THE SOUTHERN PORTION OF
THE FORECAST AREA WILL RESIDE UNDER THE FAVORABLE RIGHT REAR QUAD
OF AN UPPER LEVEL JET. THIS LIFT COMBINED WITH THE FORCING ALONG A
SLOW MOVING SFC BOUNDARY SHOULD PROMOTE GOOD COVERAGE OF SHOWERS AND
STORMS SOUTH OF HIGHWAY 460.

AS THE MID LEVEL TROF AXIS SHIFTS EAST MONDAY...PRECIP CHANCES WILL
DIMINISH LATE SUNDAY NIGHT AND EARLY MONDAY. IN A CHANGE FROM THE
PREVIOUS FORECAST...DID EXTEND CHANCE OF PRECIP IN THE SOUTHEAST
INTO MONDAY MORNING WITH THE SFC BOUNDARY STILL NEARBY.

USED A BLEND OF THE GFS/NAM MOS GUIDANCE FOR TEMPS ON MONDAY...AS
LINGERING CLOUDS KEEP TEMPS FOR REACHING THE MUCH WARMER GFS MOS
VALUES.

DRY WEATHER EXPECTED MONDAY NIGHT AND TUESDAY...WITH LOW LEVEL
THETA-E RIDGE SUPPRESSED SOUTH OF THE REGION. TEMPERATURES WILL SOAR
ABV NORMAL AGAIN BY TUESDAY AS THE SOUTHERN U.S. SUB-TROPICAL RIDGE
BEGINS TO NOSE ITS WAY INTO OUR AREA. CONSIDERING THE SIGNIFICANT
INCREASE IN 1000-850MB THICKNESSES UNDER SUNNY SKIES...PUSHED UP
HIGHS A FEW DEGREES TUESDAY NEAR THE WARMER GFS MOS GUIDANCE.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
THE LONG RANGE MODELS AND ENSEMBLES ARE IN GENERAL AGREEMENT THAT
THE SOUTHERN U.S. SUB-TROPICAL RIDGE BUILDS INTO THE MID-ATLANTIC
REGION THROUGH THURSDAY. THEN...THE UPPER FLOW FLATTENS LATE IN THE
WEEK AND INTO THE WEEKEND AS WEAK SHORT WAVES IN THE WESTERLIES
SUPPRESS THE UPPER RIDGE.

THE ECMWF AND ITS ENSEMBLES ARE THE LEAST AGGRESSIVE WITH HOW FAR
EAST THE UPPER RIDGE BUILDS...WHILE THE CANADIAN MODEL IS THE MOST
AGGRESSIVE. GENERALLY LEANED TOWARD THE GFS SOLUTION WHICH IS
BETWEEN THE TWO...BUT CLOSER TO THE ECMWF.

AS THE UPPER RIDGE BUILDS...TEMPERATURES WILL AGAIN SURGE WELL ABOVE
NORMAL...WITH GEFS ENSEMBLES SHOWING 850MB TEMPS GREATER THAN 2
STANDARD DEVIATIONS ABV NORMAL FOR WEDNESDAY THROUGH FRIDAY WHICH
APPEAR TO THE WARMEST DAYS OF THE LONG TERM PERIOD.

THERE IS STILL DISAGREEMENT IN THE MODELS IN TERMS OF THE TIMING OF
UPPER LEVEL SHORTWAVES. HOWEVER...AS PW VALUES INCREASE...THE
COVERAGE OF SHOWERS AND STORMS WILL GRADUALLY INCREASE AS THE WEEK
PROGRESSES...WITH THE BEST CHANCE OF PRECIPITATION LATE
FRIDAY/SATURDAY WHEN THE GFS/ECMWF BRING AN UPPER LEVEL
SHORTWAVE...EMBEDDED IN THE UPPER LEVEL ZONAL FLOW...THROUGH THE
AREA.

&&

.AVIATION /20Z SATURDAY THROUGH THURSDAY/...
CONDITIONS WILL REMAIN PRIMARILY VFR THROUGH THE REMAINDER OF THE
AFTERNOON AND INTO THE EARLY EVENING. THE EXCEPTION TO THIS RULE
WILL BE WHERE ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE
OCCURRING. DEVELOPMENT STARTED AROUND 16Z...NOON...AND HAS SINCE
CONTINUED TO SPREAD IN COVERAGE THIS AFTERNOON...BUT FOR THE MOST
PART STILL IS ISOLATED. UNDER THE HEAVIER SHOWERS AND STORMS
EXPECT BRIEF...LOCALIZED IFR/MVFR CONDITIONS. WHILE A SURFACE COLD
HAS PASSED TO OUR SOUTH...THE FRONT AROUND 850 MB WILL LINGER OVER
THE REGION INTO SUNDAY. THIS WILL MEAN A CONTINUED CHANCE OF
SCATTERED SHOWERS AND STORMS. WITH THE BOUNARY LAYER FRONT TO OUR
SOUTH...WE ARE EXPECTING LOW LEVEL WINDS TO CONTINUE VEERING TO
THE NORTHEAST TONIGHT. WITH LINGERING MOISTURE...ANTICIPATE LOW
END VFR CEILING TO DEVELOP ACROSS MUCH OF THE AREA OVERNIGHT.
THERE COULD BE AREAS WITH MVFR CIGS...BUT HAVE NOT INCLUDED THAT
POSSIBILITY AT THIS POINT IN THE TAFS. ALSO ANTICIPATE THE
DEVELOPMENT OF MVFR LIGHT FOG ACROSS ANY AREAS TODAY THAT RAIN.
ANY SUB-VFR VSBYS SHOULD IMPROVE TO VFR BY 15Z...11 AM...ON
SUNDAY. THE PROXIMITY OF THE 850 MB FRONT WILL HELP MAINTAIN
ISOLATED TO SCATTERED SHOWERS AND A FEW STORMS ACROSS THE AREA
TONIGHT INTO EARLY SUNDAY.

THANKS TO A STALLED 850 MB FRONT...BKN-OVC LOW END VFR CIGS AND
LOCALIZED MVFR CIGS WILL CONTINUE SUNDAY AFTERNOON INTO SUNDAY
NIGHT ALONG WITH ISOLATED TO SCATTERED SHOWERS AND STORMS.

MAINLY VFR CONDITIONS WILL EXIST MONDAY THROUGH WEDNESDAY AS HIGH
PRESSURE RETURNS TO THE AREA. LATE NIGHT MVFR VALLEY FOG WILL BE
POSSIBLE...ESPECIALLY IN THOSE AREAS THAT RECEIVED SIGNIFICANT
RAIN SATURDAY THROUGH SUNDAY.

ON THURSDAY...A COLD FRONT WILL HEAD SOUTH THROUGH THE AREA.
ANTICIAPTE LOCALIZED MVFR CONDITIONS WITH ISOLATED TO SCATTERED
SHOWERS AND STORMS.

&&

.CLIMATE...
RECORD MAXIMUM LOW TEMPERATURE RECORDS MAY BE SET TODAY. THREE
LOCATIONS HAVE THE POTENTIAL OF DOING SO...ROANOKE AND BLACKSBURG
VA AND BLUEFIELD WV.

SATURDAY RECORDS:
ROANOKE.....74 SET IN 2002
BLACKSBURG...68 SET IN 2005
BLUEFIELD....69 SET IN 2004

IF THE TEMPERATURE DOES NOT FALL BELOW THESE RECORD TEMPERATURES
BEFORE MIDNIGHT STANDARD TIME TONIGHT...NEW RECORDS WILL BE
ESTABLISHED. SO FAR TODAY...THE LOW TEMPERATURES HAVE BEEN 75 AT
ROANOKE...71 AT BLACKSBURG...AND 71 AT BLUEFIELD.

&&

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

&&

SYNOPSIS...DS
NEAR TERM...DS
SHORT TERM...PH
LONG TERM...PH
AVIATION...DS
CLIMATE...

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BLACKSBURG VA
359 PM EDT SAT JUL 30 2011

NCZ001>006-018>020-VAZ007-009>020-022>024-032>035-043>047-058-059-
WVZ042>045-312000-
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-
359 PM EDT SAT JUL 30 2011

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...THIS AFTERNOON AND TONIGHT.

ISOLATED STRONG TO SEVERE THUNDERSTORMS WILL CONTINUE TO BE POSSIBLE
AS WE HEAD INTO THIS EVENING AS A FRONTAL BOUNDARY STALLS OVER THE
REGION. THE MAIN THREATS FROM THESE STORMS WILL BE VERY HEAVY
RAIN AND DAMAGING WIND.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BLACKSBURG VA
327 PM EDT SAT JUL 30 2011

VAZ024-302000-
ROCKBRIDGE VA-
327 PM EDT SAT JUL 30 2011

...A STRONG THUNDERSTORM WILL AFFECT ROCKBRIDGE COUNTY...

AT 323 PM EDT...A STRONG THUNDERSTORM WAS LOCATED OVER
COLLIERSTOWN...MOVING SOUTHEAST AT 10 MPH.

WIND GUSTS TO 50 MPH AND SMALL HAIL ARE POSSIBLE WITH THIS STORM.

THIS STORM WILL BE NEAR NATURAL BRIDGE AROUND 400 PM.

THE PUBLIC IS ENCOURAGED TO RELAY REPORTS OF STRONG WINDS...HAIL OR
FLOODING TO THE NATIONAL WEATHER SERVICE IN BLACKSBURG BY CALLING
1...8 6 6...2 1 5...4 3 2 4...WHEN YOU CAN DO SO SAFELY.

LAT...LON 3777 7928 3774 7930 3761 7943 3762 7944
      3761 7946 3759 7945 3754 7950 3768 7967
      3773 7969 3781 7965 3783 7962 3788 7960

SK

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BLACKSBURG VA
332 PM EDT SAT JUL 30 2011

VAZ022-033-302030-
FRANKLIN VA-ROANOKE VA-
332 PM EDT SAT JUL 30 2011

...A STRONG THUNDERSTORM WILL AFFECT FRANKLIN AND ROANOKE COUNTIES...

AT 327 PM EDT...A STRONG THUNDERSTORM WAS DEVELOPING OVER ROANOKE...
MOVING SOUTHEAST AT 10 MPH.

WIND GUSTS TO 50 MPH AND SMALL HAIL MAY BE POSSIBLE WITH THIS STORM.

THIS STORM WILL BE NEAR ROANOKE MOUNTAIN AROUND 340 PM AND BOONES
MILL AROUND 405 PM IF IT HOLDS TOGETHER.

THE PUBLIC IS ENCOURAGED TO RELAY REPORTS OF STRONG WINDS...HAIL OR
FLOODING TO THE NATIONAL WEATHER SERVICE IN BLACKSBURG BY CALLING
1...8 6 6...2 1 5...4 3 2 4...WHEN YOU CAN DO SO SAFELY.

LAT...LON 3737 7997 3730 7985 3726 7985 3721 7984
      3723 7982 3720 7980 3706 8001 3714 8017

SK

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BLACKSBURG VA
336 PM EDT SAT JUL 30 2011

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

0245 PM     HAIL             3 S NATURAL WELL        37.87N 79.98W
07/30/2011  E1.00 INCH       ALLEGHANY          VA   PUBLIC

            HAIL SLIGHTLY LARGER THAN QUARTERS FELL AT CLIFFVIEW
            DRIVE.

&&

HYSELL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BLACKSBURG VA
401 PM EDT SAT JUL 30 2011

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

0350 PM     TSTM WND DMG     4 SSW ROANOKE           37.23N 79.99W
07/30/2011                   ROANOKE            VA   PUBLIC

            3 TREES DOWN ON HOME AND POWER LINES

&&

EH

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BLACKSBURG VA
410 PM EDT SAT JUL 30 2011

VAZ033-302045-
FRANKLIN VA-
410 PM EDT SAT JUL 30 2011

...A STRONG THUNDERSTORM WILL AFFECT FRANKLIN COUNTY...

AT 406 PM EDT...A STRONG THUNDERSTORM WAS LOCATED 5 MILES NORTH OF
FERRUM...MOVING SOUTHEAST AT 5 MPH.

WIND GUSTS TO 50 MPH AND SMALL HAIL ARE POSSIBLE WITH THIS STORM.

THIS STORM WILL BE NEAR FERRUM AROUND 445 PM.

THE PUBLIC IS ENCOURAGED TO RELAY REPORTS OF STRONG WINDS...HAIL OR
FLOODING TO THE NATIONAL WEATHER SERVICE IN BLACKSBURG BY CALLING
1...8 6 6...2 1 5...4 3 2 4...WHEN YOU CAN DO SO SAFELY.

LAT...LON 3695 7981 3681 8001 3699 8011 3709 7998

SK

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BLACKSBURG VA
412 PM EDT SAT JUL 30 2011

VAZ034-035-045-302115-
AMHERST VA-BEDFORD VA-CAMPBELL VA-
412 PM EDT SAT JUL 30 2011

...A STRONG THUNDERSTORM WILL AFFECT AMHERST...BEDFORD AND CAMPBELL
COUNTIES...

AT 410 PM EDT...A STRONG THUNDERSTORM WAS LOCATED 5 MILES SOUTHWEST
OF FORKS OF BUFFALO...MOVING SOUTHEAST AT 5 MPH.

WIND GUSTS TO 50 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. EXPECT FREQUENT
CLOUD TO GROUND LIGHTNING FROM THIS STORM. DO NOT STAY IN THE OPEN OR
SEEK SHELTER UNDER TREES WHEN LIGHTNING THREATENS...MOVE INDOORS WHEN
A THUNDERSTORM APPROACHES.

THIS STORM WILL BE NEAR PLEASANT VIEW AROUND 420 PM...COLEMAN FALLS
AROUND 445 PM...NAOLA AROUND 450 PM AND ELON AROUND 515 PM.

THE PUBLIC IS ENCOURAGED TO RELAY REPORTS OF STRONG WINDS...HAIL OR
FLOODING TO THE NATIONAL WEATHER SERVICE IN BLACKSBURG BY CALLING
1...8 6 6...2 1 5...4 3 2 4...WHEN YOU CAN DO SO SAFELY.

LAT...LON 3779 7920 3779 7918 3761 7893 3736 7918
      3755 7946 3756 7944 3758 7944 3765 7938
      3767 7934 3771 7931 3781 7923

SK