Special Weather Statement, NWS Blacksburg, VA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
903 PM EDT SAT JUL 21 2012

.SYNOPSIS...
A FRONTAL BOUNDARY WILL LINGER IN NORTH CAROLINA INTO SUNDAY
BEFORE DISSIPATING. THERE WILL BE A FEW DISTURBANCES MOVING IN
FROM TIME TO TIME INTO TUESDAY KEEPING THE THREAT OF STORMS
AROUND.

&&

.NEAR TERM /THROUGH SUNDAY/...
AS OF 830 PM EDT SATURDAY...

FRONT REMAINS STUCK NEAR THE VA/NC BORDER THIS EVENING WITH
RESIDUAL LINE OF STORMS ALONG OLD OUTFLOW MAINLY TO THE SOUTH OF
THE CWA. HOWEVER LOW LEVEL THETA-E REMAINS QUITE HIGH NORTH OF THE
BOUNDARY WITH ANALYSIS SHOWING LINGERING LOW LEVEL CONVERGENCE
ALONG THE BLUE RIDGE WHERE WEAK UPSLOPE EASTERLY FLOW HAS
DEVELOPED. WITH DECENT CAPE STILL IN PLACE OVER THE SOUTH AND
OLD OUTFLOW NEAR THE BLUE RIDGE...WILL LINGER ISOLATED-SCTD
SHRA/TSRA A BIT LONGER THAN PREVIOUS...AND THEN BRING IN FOG/DZ
WELL AFTER MIDNIGHT WHEN THE DEEPER EASTERLY FLOW SHOULD SPILL
ACROSS MOST OF THE AREA. ELSW...ESPCLY TO THE WEST...CLOUDS AND
SHRA REMAIN LIMITED WITH A PERIOD OF MOSTLY CLEAR TO PC LIKELY
BEFORE SOME LOW DECK SLIDES BACK TO THE SW WITH THE WEAK WEDGE
LATE. TWEAKED TEMPS DOWN A FEW DEGREES SIMILAR TO THE LATEST
LAV MOS UNDER THE SLIGHTLY COOLER BUT MORE HUMID NE FLOW LATER ON.

AS OF 225 PM EDT SATURDAY...

AN UPPER LEVEL RIDGE IS STRETCHED FROM THE CENTRAL PLAINS EAST INTO
THE OHIO VALLEY. ANOTHER RIDGE IS STRETCHED FROM BERMUDA BACK INTO
SOUTHEASTERN COASTAL STATES. IN BETWEEN THESE TWO RIDGES AND OVER
THE MID ATLANTIC/TENNESSEE VALLEY IS A WEAK UPPER LEVEL TROUGH. ALSO
DRAPED OVER THE REGION IS A WEAK SURFACE BOUNDARY. COUPLED WITH THE
TROUGH AND BOUNDARY...CONVERGENCE AND DAYTIME HEATING WILL BRING
SCATTERED SHOWERS AND THUNDERSTORMS TO THE AREA THIS AFTERNOON AND
EVENING. A FEW OF THESE STORMS MAY BECOME SEVERE EAST OF THE BLUE
RIDGE TOWARD THE NC/VA BORDER SOUTH. PWATS ARE 1.50-2.00 INCHES AND
STEERING CURRENTS ARE WEAK. THEREFORE...ANY STORM THIS AFTERNOON
WILL ALSO HAVE THE POTENTIAL TO DROP 1-3 INCHES OF RAIN.

OVERNIGHT...SHOWERS WILL FADE AND WEAK HIGH PRESSURE/WEDGE BUILDS
OVER THE AREA. ISENTROPIC LIFT INCREASES IN THIS MOIST ATMOSPHERE
FOR AREAS ALONG AND EAST OF THE BLUE RIDGE TO SEE LIGHT RAIN/DRIZZLE
DURING THE EARLY MORNING HOURS SUNDAY. IF DRIZZLE OR RAIN DOES NOT
FALL...THESE AREA WILL LIKELY SEE DENSE FOG IN THE MORNING.

THE UPPER LEVEL RIDGES WILL REMAIN IN THEIR RESPECTED AREAS WHILE
THE TROUGH WEAKENS OVER THE REGION. THE SURFACE BOUNDARY SHOULD
DRIFT FARTHER SOUTH IN TO THE CAROLINAS SUNDAY. WITH AFTERNOON
HEATING AND TROUGHINESS ALOFT...ISOLATED SHOWERS AND THUNDERSTORMS
ARE POSSIBLE...MAINLY SOUTH.

THE WEDGE WILL ERODE BY THE AFTERNOON. TEMPERATURES SHOULD REBOUND
QUICKLY AND LEVEL OFF NEAR NORMAL.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/...
AS OF 200 PM EDT SATURDAY...

WILL USE A MODEL BLEND OF THE 00Z ECMWF/12Z GFS/09Z SREF THIS
PERIOD. THE MAIN ISSUE WILL BE SHORTWAVES FLOWING IN THE NW FLOW
ALOFT AND HOW STRONG ANY MCS UPSTREAM GETS AND HOW FAR EAST IT CAN
MAKE IT. THE ECMWF IS ADVERTISING A QUICKER MOVEMENT TO ONE WAVE
COMING ACROSS THE NRN TIER OF THE CWA MON MORNING EARLY THEN OUT TO
THE COAST IN THE AFTN...WHILE THE GFS IS SLOWER/WEAKER. WILL KEEP
POPS IN THE CHANCE RANGE WITH HIGHEST OVER THE NW AND SW...WITH
MODEST THETA-E RIDGING IN THE MTNS AND ANOTHER WEAKER SHORTWAVE
SHOWING UP IN THE AFTN.

AREA TO STAY INT HE WARM SECTOR THIS PERIOD WITH FRONTAL BOUNDARY
LINGERING MORE OVER THE SRN GREAT LAKES INTO MID ATLANTIC...BUT WILL
STILL SEE STORMS OFF AND ON THROUGH TUE NIGHT. MODELS SEEM TO BE IN
BETTER AGREEMENT INTO TUESDAY WITH PRECIP BUT DIFFERENCES EXIST ON
THE INDIVIDUAL VORTS. THE NAM/ECMWF SHOWING THE MAIN TRACK TUE FROM
THE SRN GREAT LAKES 12Z TUE TO NRN VA/MID ATLANTIC...WHILE WEAKER
SHORTWAVE SHIFTS ACROSS THE TN VALLEY. THE GFS ON THE OTHER HAND
BRINGS THE NRN WAVE IN QUICKER AND OUT TO SEA BY 18Z TUE WITH NEXT
TWO WAVES LINED UP FROM INDIANA TO ERN KY BY THE END OF THE DAY. FOR
NOW IT STILL LOOKS LIKE THE POPS CAN BE KEPT IN THE CHANCE
RANGE...BUT THINK THE NRN AND WRN CWA COULD SEE A BETTER THREAT BY
TUESDAY AFTN.

TEMPS THIS PERIOD WERE KEPT JUST A DEGREE OR TWO COOLER THINKING
MORE CLOUD COVER AND CONVECTION MAY KEEP TEMPS DOWN...HOWEVER
TUESDAY SHOULD BE HOT AS THE WRLY FLOW WILL BE STRONGER AND IF THE
SUN STAYS OUT LONGER...THE PIEDMONT COULD SOAR TOWARD THE CENTURY
MARK...BUT COULD ALSO SEE A LITTLE LOWER DEWPOINTS. FOR NOW STICKING
WITH MID 90S EAST TO MID TO UPPER 80S WEST.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
AS OF 1222 PM EDT SATURDAY...

LOOKS LIKE WE WILL BE STUCK IN A HUMID SOMEWHAT STORMY BUT TYPICAL
LATE JULY PATTERN WITH THE RIDGE STAYING RIGHT ON THE SWRN DOORSTEP
OF OUR REGION...WITH THE BLACKSBURG FORECAST AREA REMAINING ON THE
SRN FRINGE OF THE TROUGH OVER THE NORTHEAST.

WILL BE GOING WITH DAILY THREAT OF SHRA/TSRA BUT WILL SEE ENHANCED
PROBABILITIES AS A SERIES OF SHORTWAVES GRAZE BY...BUT TIMING AT
THIS POINT IS UP IN THE AIR...WITH FRONTAL BOUNDARY SWINGING TOWARD
US IN THE WED-THU TIME FRAME THEN LIFTING NORTH AGAIN BY THE WEEKEND.

LOWS AT NIGHT WILL STAY IN THE 60S IN THE MTNS WITH LOWER 70S EAST
WITH HIGHS IN THE MID-UPPER 80S MTNS TO LOWER TO MID 90S EAST. OF
COURSE ANY CONVECTION AND OR BLOWOFF OF STORMS WILL LIMIT SOME
HEATING FROM TIME TO TIME DURING THE DAY.

&&

.AVIATION /01Z SUNDAY THROUGH THURSDAY/...
AS OF 650 PM EDT SATURDAY...

BROKEN AXIS OF CONVECTION ALONG THE FRONT HAS NOW SLIPPED JUST SOUTH
OF THE AREA LEAVING ONLY ISOLATED STORMS ALONG THE BLUE RIDGE INTO
SOUTHSIDE VA GIVEN LEFTOVER CONVERGENCE ZONE PER EASTERLY FLOW.
COULD STILL SEE A TSRA OR TWO AFFECT AREAS FROM KBCB/KROA TO KDAN
DURING THE NEXT FEW HOURS SINCE SO MUCH OUTFLOW AROUND SO
INCLUDING A VCTS OR TEMPO MENTION IN SPOTS. ONCE HEATING FADES OR THE
LINE TO THE SE ORGANIZES MORE...EXPECT ONLY ISOLATED SHRA TO
REMAIN AFTER DARK THIS EVENING.

OTRW THE FRONT SHOULD CONTINUE TO DRIFT SOUTH TONIGHT. BEHIND THE
FRONT...COOL EASTERLY FLOW WILL HELP SETUP A WEAK WEDGE WITH LOWER
CLOUDS DEVELOPING IN FROM THE EAST/NE. WITH AN INCREASE IN
ISENTROPIC LIFT...LOWERING OF THE CLOUD DECK BELOW MVFR WITH AREAS
OF DRIZZLE IS POSSIBLE ESPECIALLY ACROSS THE NORTH AND ALONG THE
BLUE RIDGE WITH MEDIUM TO HIGH CONFIDENCE OF THIS BECOMING
WIDESPREAD BY DAYBREAK. THESE CLOUDS MAY NOT LIFT UNTIL MIDDAY SUNDAY.
KBLF LOOKS TO KEEP A MOIST WEST WIND OVERNIGHT. UPSLOPE
ENHANCEMENT AT KBLF MAY KEEP LIFR CEILINGS DEEP INTO SUNDAY MORNING
BUT LOW CONFIDENCE AT THIS POINT GIVEN SOME DRYING THAT IS ONGOING
ATTM. THUS ONLY CHANGES OVERNIGHT WERE TO DELAY THE ONSET OF THE
LOWER CIGS OUTSIDE OF WHERE EARLIER RAINFALL OCCURRED AND TO LOWER
VSBYS IN FOG AND/OR -DZ ACROSS THE SOUTH BY MORNING.

ONCE CLOUDS BURN OFF...AN UPPER LEVEL TROUGH AND AFTERNOON HEATING
MAY GENERATE AN ISOLATED SHOWER OR THUNDERSTORM SUNDAY AFTERNOON
BUT TOO ISOLATED TO INCLUDE MENTION SUNDAY AFTERNOON. THINK ALL
LOCATIONS SHOULD FINALLY REACH VFR CIGS BY EARLY OR MID AFTERNOON
SUNDAY WITH MORE SCTD NATURE CLOUDS UP NORTH. FOG MAY BE
PROBLEMATIC ACROSS THE MOUNTAIN VALLEYS SUNDAY NIGHT INTO MONDAY
MORNING.

NW FLOW ALOFT LOOKS TO PERSIST MONDAY THRU THURSDAY...LIKELY RESULTING
IN BOUTS OF SHRA/TSRA THRU THE PERIOD. OTHERWISE EXPECTING VFR
OUTSIDE OF ANY PERIODS OF THUNDERSTORMS...AND CONTINUED LATE NIGHT
FOG THROUGH MID OR LATE WEEK.

&&

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

&&

SYNOPSIS...AMS/WP
NEAR TERM...AMS/JH/RCS
SHORT TERM...WP
LONG TERM...WP
AVIATION...AMS/JH/RCS

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BLACKSBURG VA
915 PM EDT SAT JUL 21 2012

NCZ001>006-018>020-VAZ007-009-010-012-013-015>017-032-033-043-044-
058-059-230115-
ASHE-ALLEGHANY NC-SURRY-STOKES-ROCKINGHAM-CASWELL-WATAUGA-WILKES-
YADKIN-TAZEWELL-SMYTH-BLAND-WYTHE-PULASKI-GRAYSON-CARROLL-FLOYD-
PATRICK-FRANKLIN-HENRY-PITTSYLVANIA-HALIFAX-CHARLOTTE-
915 PM EDT SAT JUL 21 2012

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

.DAY ONE...TONIGHT.

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

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

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

VAZ011-014-018>020-022>024-034-035-045>047-WVZ042>045-230115-
GILES-MONTGOMERY-CRAIG-ALLEGHANY VA-BATH-ROANOKE-BOTETOURT-
ROCKBRIDGE-BEDFORD-AMHERST-CAMPBELL-APPOMATTOX-BUCKINGHAM-MERCER-
SUMMERS-MONROE-GREENBRIER-
915 PM EDT SAT JUL 21 2012

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

.DAY ONE...TONIGHT.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

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

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BLACKSBURG VA
440 PM EDT SAT JUL 21 2012

NCZ005-VAZ043-212145-
HENRY VA-ROCKINGHAM NC-
440 PM EDT SAT JUL 21 2012

...STRONG THUNDERSTORMS WILL AFFECT HENRY AND ROCKINGHAM COUNTIES...

AT 438 PM EDT...STRONG THUNDERSTORMS WERE ALONG A LINE FROM EDEN TO 4
MILES NORTHWEST OF MADISON...MOVING EAST AT 10 MPH.

WIND GUSTS TO 40 MPH AND HAIL UP TO DIME SIZE ARE POSSIBLE WITH THESE
STORMS. VERY HEAVY RAIN WILL FALL FROM THESE STORMS...AND WILL CAUSE
WATER TO POND ON ROADS AND QUICKLY FILL ROADSIDE DITCHES AND SMALL
STREAMS. EXPECT FREQUENT CLOUD TO GROUND LIGHTNING FROM THESE STORMS.
DO NOT STAY IN THE OPEN OR SEEK SHELTER UNDER TREES WHEN LIGHTNING
THREATENS...MOVE INDOORS WHEN A THUNDERSTORM APPROACHES.

THESE STORMS WILL BE NEAR STONEVILLE AROUND 445 PM...MAYODAN AROUND
450 PM...EDEN AROUND 500 PM...DRAPER AROUND 505 PM...MAYFIELD AROUND
535 PM AND WENTWORTH AROUND 540 PM.

LAT...LON 3642 8003 3648 8003 3658 7984 3656 7971
      3654 7971 3655 7962 3653 7951 3635 7985

16

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BLACKSBURG VA
546 PM EDT SAT JUL 21 2012

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

0452 PM     TSTM WND DMG     4 NW STONEVILLE         36.50N 79.96W
07/21/2012                   ROCKINGHAM         NC   911 CALL CENTER

            TREE DOWN ON SMITH ROAD

&&

FISHER

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BLACKSBURG VA
547 PM EDT SAT JUL 21 2012

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

0515 PM     TSTM WND DMG     WNW WENTWORTH           36.40N 79.77W
07/21/2012                   ROCKINGHAM         NC   911 CALL CENTER

            TREE DOWN ON ROUTE 65

&&

FISHER

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BLACKSBURG VA
547 PM EDT SAT JUL 21 2012

VAZ033-212245-
FRANKLIN VA-
547 PM EDT SAT JUL 21 2012

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

AT 543 PM EDT...A STRONG THUNDERSTORM WAS LOCATED OVER FERRUM...
MOVING SOUTHEAST AT 10 MPH.

WIND GUSTS TO 40 TO 50 MPH ARE POSSIBLE WITH THIS STORM. 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 SYDNORSVILLE AROUND 635 PM AND OAK LEVEL
AROUND 640 PM.

LAT...LON 3681 8005 3695 8011 3700 7998 3680 7975
      3679 7976 3680 7977 3679 7982 3683 8000
      3680 8001 3679 8002 3679 8001 3678 8003

16

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BLACKSBURG VA
755 PM EDT SAT JUL 21 2012

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

0600 PM     TSTM WND DMG     5 NNE JERICHO           36.36N 79.33W
07/21/2012                   CASWELL            NC   LAW ENFORCEMENT

            THE CASWELL COUNTY SHERIFFS OFFICE REPORTED FIVE TREES
            BLOWN DOWN NEAR THE INTERSECTION OF HIGHWAY 62 AND BURTON
            CHAPEL ROAD.

0610 PM     TSTM WND DMG     1 N JERICHO             36.29N 79.37W
07/21/2012                   CASWELL            NC   LAW ENFORCEMENT

            THE CASWELL COUNTY SHERIFFS OFFICE REPORTED A TREE BLOWN
            DOWN ALONG HIGHWAY 62 NEAR THE COMMUNITY OF JERICHO.

&&

16

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BLACKSBURG VA
926 PM EDT SAT JUL 21 2012

NCZ004-220230-
STOKES NC-
926 PM EDT SAT JUL 21 2012

...A STRONG THUNDERSTORM WILL AFFECT STOKES COUNTY...

AT 924 PM EDT...A STRONG THUNDERSTORM WAS LOCATED 4 MILES WEST OF
DANBURY...MOVING SOUTHEAST AT 5 MPH.

WIND GUSTS TO 40 MPH ARE POSSIBLE WITH THIS STORM.

THIS STORM WILL BE NEAR CAPELLA AROUND 940 PM...HANGING ROCK STATE
PARK AROUND 945 PM...DANBURY AROUND 1000 PM...MEADOWS AROUND 1025 PM
AND DILLARD AROUND 1030 PM.

THIS STORM IS INTENSIFYING QUICKLY. IF IT BECOMES MUCH STRONGER...A
SEVERE THUNDERSTORM WARNING MAY BE ISSUED.

LAT...LON 3641 8007 3628 8025 3644 8039 3651 8030

16