Special Weather Statement, NWS Blacksburg, VA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BLACKSBURG VA
1010 PM EDT MON APR 30 2012

.SYNOPSIS...
A WARM FRONT WILL LIFT NORTH THROUGH THE AREA OVERNIGHT WHILE LOW
PRESSURE HEADS EASTWARD TOWARD PENNSYLVANIA. TUESDAY THROUGH
FRIDAY...HIGH PRESSURE WILL BE PARKED OFF THE ATLANTIC COAST WITH
A FETCH OF GULF OF MEXICO MOISTURE RIDING NORTH ALONG THE
APPALACHIANS. A BACKDOOR COLD FRONT WILL MAKE A RUN AT THE AREA
LATE IN THE UPCOMING WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
AS OF 1000 PM EDT MONDAY...

ISSUED DENSE FOG ADVISORY FOR WEDGE REGION...CONSIDERING ROANOKE
QUICKLY FELL TO ZERO VIS ALREADY TONIGHT. FOG MAY BE NOT AS DENSE
ACROSS AMHERST AND ROCKBRIDGE...ALTHOUGH THERE STILL COULD BE A
QUARTER MILE VIS ACROSS THE SOUTHWESTERN PORTIONS OF THOSE
COUNTIES...WHERE COOL AIR THANKS TO THE WEDGE TYPICALLY POOLS.
STORMS STILL ACROSS NW NC WILL BEGIN TO DIE OFF BY MIDNIGHT...WITH
POSSIBLY A FEW SHOWERS SURVIVING INTO SOUTHSIDE VIRGINIA. MASS OF
STORMS NEARING THE OHIO RIVER WILL ARRIVE ACROSS THE LWB/BLF
CORRIDOR AROUND 7Z/3A. STORMS WILL PROBABLY MOVE JUST NORTH ENOUGH
OF DUE EAST TO HOPEFULLY MISSED THE RAIN SOAKED
GRAYSON/ASHE/WATAUGA COUNTIES...OR SOME WATER PROBLEMS WILL LIKELY
DEVELOP. WILL NEED A CONSISTENT WESTERLY COMPONENT TO ERASE THE
LLVL MOISTURE...AND WOULDN'T BE SURPRISED IF FOG AND LOW CLOUDS
HANG INTO A PORTION OF TUESDAY MORNING.

AS OF 630 PM EDT MONDAY...

REDUCED TEMPS FOR ROA/LYH AND CAD AREA TO THE NE AS THEY ARE
SOCKED IN AND WILL NOT BE WARMING TO FORECASTED MAX T.
ALSO...CURRENT TEMPS IN THE WEDGE WERE COLDER THAN FORECASTED MIN
T SO THOSE WERE ADJUSTED DOWNWARD. LAMP GUIDANCE BULLISH ON DENSE
FOG IN THE WEDGE TONIGHT...SO ADDED AREAS OF FOG TO WX GRID.
SOME BIG STORMS NEAR WHITETOP MTN AND NW NC...WHICH MAY BE
EFFICIENT HAIL PRODUCERS ALTHOUGH NO REPORTS YET...ESPECIALLY
CONSIDERING THE STEEP LAPSE RATES IN THE -10C TO -20C HAIL GROWTH
ZONE. LATEST NAM AND RLX WRF KEEPING EXTREME SW VA AND NW NC WITH
STORMS TONIGHT WITH THEIR EASTWARD PROGRESSION HITTING THE BRICK
WALL OF STABILITY WHICH IS THE WEDGE.THIS MAY KEEP THEM MOSTLY IN
NC AND JUST ALONG THE NC/VA BORDER TONIGHT. LOWERED POPS NORTH OF
THESE AREAS TO ISOLATED...ADDITIONAL STORMS NOW ACROSS IN MAKE A
RUN AT LWB/BLF TOWARDS DAWN. CLOUDS WILL EXPAND INTO THE NEW RIVER
VALLEY TONIGHT.

AS OF 306 PM EDT MONDAY...

A WARM FRONT WAS ORIENTED NORTH TO SOUTH ACROSS THE WESTERN PORTION
OF THE REGION. THE LATEST ANALYSIS PLACED IT FROM NEAR BOONE NC TO
BETWEEN BLUEFIELD WV AND BLACKSBURG WV AND FARTHER NORTH TO BETWEEN
BECKLEY AND LEWISBURG WV. LAPS SURFACE BASED CONVECTIVE PARAMETERS
WAS INDICATING CAPE VALUES AROUND 2000-2500 J/KG ALONG THE FRONT
WITH CORRESPONDING LI VALUES AROUND -5 TO -7. THERE HAS BEEN SOME
DECENT CUMULUS DEVELOPMENT NEAR THE BOUNDARY...BUT AS OF YET...NO
SHOWERS OR STORMS. LAPS SOUNDINGS FOR BLUEFIELD SHOW A WEAK AROUND
700-650 MB. WE ARE ANTICIPATING A BIT MORE WARMING IN THE WEST THIS
AFTERNOON...AND THIS MAY BE THE ADDED FUEL WE NEED FOR SHOWER AND
STORM DEVELOPMENT. WE HAVE BEEN ADVERTISING THE DEVELOPMENT LATE
THIS AFTERNOON THAT WOULD CARRY INTO THE EVENING HOURS. WILL
CONTINUE TO DO SO WITH THIS PACKAGE. LATER IN THE EVENING...THE
PREVAILING FLOW WOULD ADVECT ANY ACTIVITY EAST OF THE MOUNTAINS.

CURRENTLY EAST OF THE MOUNTAINS...THE HIGH PRESSURE WEDGE HAS BEEN
SLOW TO ERODE AND GIVE UP ITS CLOUD COVER. AS OF THIS
DISCUSSION...BLACKSBURG WAS 12 DEGREES WARMER THAN ROANOKE...AND
BLUEFIELD WAS 10 DEGREES WARMER THAN BLACKSBURG. WHILE SATELLITE
IMAGERY SHOWS CLOUD COVER ERODING ALONG THE EDGES...THE AREA
BETWEEN ROANOKE...LYNCHBURG...AND DANVILLE WILL LIKELY HOLD ON TO
MOST OR ALL OF ITS CLOUD COVER THROUGH THE EVENING.

OVERNIGHT...WE WILL SEE THE WARM FRONT LIFT ACROSS THE AREA WITH
PREVAILING WINDS BECOMING S-SW ACROSS THE ENTIRE AREA. THIS WILL
ERODE THE REMAINDER OF THE WEDGE. SOME AREAS MAY SEE EARLY LOWS WITH
TEMPERATURES STEADY OR RISING SLIGHTLY THROUGH THE NIGHT.
PRECIPITATION CHANCES WILL BE GREATEST FIRST THIS EVENING ACROSS THE
MOUNTAINS WITH THE CONVECTION...AND THEN SHIFT EASTWARD AS THE
PREVAILING FLOW TAKES THE ACTIVITY EASTWARD OVER THE WEDGE.

BY EARLY TUESDAY MORNING...OUR FOCUS RETURNS TO WESTERN PARTS OF THE
AREA AS AN INCREASED FETCH OF LOW LEVEL MOISTURE ADVECTS INTO THE
REGION FROM THE GULF OF MEXICO. AN APPROACHING COLD FRONT WILL HELP
INITIATE SHOWERS AND STORMS THROUGH THE DAY WITH THE BEST COVERAGE IN
THE AFTERNOON.

&&

.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
AS OF 300 PM EDT SUNDAY...

HAVE MAINTAINED PROBABILITY OF RAIN TUESDAY EVENING EXPECTING
ONGOING SHOWERS AN THUNDERSTORMS. THE REST OF TUESDAY NIGHT AND ON
ON WEDNESDAY REMNANTS OF TUESDAY BOUNDARY MAY STILL BE SOMEWHERE IN
THE SOUTHERN COUNTY WARNING AREA AND THE MODELS ARE ALSO HINTING AT
SOME LEE TROFING. OVERALL STILL LOOKING AT MAINLY DIURNALLY DRIVEN
SHOWERS AND THUNDERSTORMS BOTH WEDNESDAY AND THURSDAY AFTERNOON AND
EVENING.

IT IS POSSIBLE THAT SOME OF THE WEDGE MOVES BACK INTO THE NORTHEAST
COUNTIES OF THE FORECAST AREA ON WEDNESDAY WITH HIGH PRESSURE NOSING
DOWN THE EAST COAST FROM NEW ENGLAND. ASIDE FROM THIS POTENTIAL FOR
COOLER AIR...HAVE STAYED CLOSER TO THE WARMER MAV GUIDANCE FOR
TEMPERATURES THROUGH THE PERIOD.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 300 PM EDT SUNDAY...

MODELS KEEP BROAD UPPER RIDGE OVER THE SOUTHEAST UNITED STATES
THROUGH THE PERIOD. A WEAK SHORT WAVE CROSSES THE FORECAST AREA ON
SATURDAY THEN A COLD FRONT DROPS SOUTH THROUGH THE MID ATLANTIC
REGION ON SUNDAY NIGHT AND MONDAY. OTHERWISE THE BAROCLINIC ZONE
REMAINS WELL NORTH ACROSS THE GREAT LAKES AND NEW ENGLAND...MEANING
THE FORECAST AREA STAYS WELL IN THE WARM UNSTABLE AIR UNTIL MONDAY.
TEMPERATURES WILL REMAIN ABOVE NORMAL THROUGH SUNDAY.

&&

.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
AS OF 730 PM EDT MONDAY...

WEDGE IS EXPANDING AND INTENSIFYING AS THE SUN SETS THIS EVENING.
THIS IS PROBABLY ONE OF THE MOST EXTREME WEDGE CASES I HAVE SEEN
IN MY 5 YEARS HERE. BLF/LWB ARE CLR AND NEAR 80F. ROA/LYH AND
POINTS NEARBY ARE ALREADY AT 1/4SM OR LESS...DENSE FOG AND CIGS IN
THE DIRT. THESE VLIFR CONDS WILL CONTINUE FOR THE REST OF THE
OVERNIGHT AND POSSIBLY PAST SUNRISE TUESDAY. WILL LIKELY ISSUE A
DENSE FOG ADVISORY IN THE NEXT FEW HOURS FOR AREAS IMPACTED. LOW
CLOUDS WILL SLOWLY EXPAND TONIGHT...PUTTING KDAN AT IFR CIGS/VIS AND
LATER TONIGHT. SIMILAR CONDITIONS MAY ALSO SEEP SW INTO BCB. A
LINE OF TSRA MAY AFFECT LWB/BLF CORRIDOR NEAR DAWN.

BY TUESDAY...STRONG SOUTHWEST FLOW IN THE LOW LEVELS WILL PREVAIL
WITH SURFACE GUSTS LIKELY IN THE 15-20KT RANGE. SCATTERED SHOWERS
AND A FEW THUNDERSTORMS MAY DEVELOP BY 18Z...2PM

SUMMER LIKE PATTERN TUESDAY THROUGH FRIDAY WITH ISOLATED TO
SCATTERED SHOWERS AND STORMS. CONDITIONS PRIMARILY VFR EXCEPT
DIRECTLY UNDER THE MORE SUBSTANTIAL CONVECTIVE CELLS...AND ALSO IN
ASSOCIATION WITH LATE NIGHT RIVER AND VALLEY FOG IN AREAS THAT
RECEIVED PRECIPITATION THE DAY BEFORE.

SATURDAY MAY BRING A RETURN TO PATCHY AREAS OF SUB-VFR
CONDITIONS...ESPECIALLY IN THE NORTH...AS A BACKDOOR COLD FRONT
APPROACHES.

&&

.RNK WATCHES/WARNINGS/ADVISORIES...
VA...DENSE FOG ADVISORY UNTIL 8 AM EDT TUESDAY FOR VAZ022>024-034-
     035-045.
NC...NONE.
WV...NONE.

&&

SYNOPSIS...DS/KM
NEAR TERM...DS/KM
SHORT TERM...AMS
LONG TERM...AMS
AVIATION...DS/KM

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE BLACKSBURG VA
1017 PM EDT MON APR 30 2012

NCZ004>006-VAZ007-009>014-016>020-032-033-043-044-046-047-058-059-
WVZ042>045-020230-
STOKES-ROCKINGHAM-CASWELL-TAZEWELL-SMYTH-BLAND-GILES-WYTHE-PULASKI-
MONTGOMERY-CARROLL-FLOYD-CRAIG-ALLEGHANY VA-BATH-PATRICK-FRANKLIN-
HENRY-PITTSYLVANIA-APPOMATTOX-BUCKINGHAM-HALIFAX-CHARLOTTE-MERCER-
SUMMERS-MONROE-GREENBRIER-
1017 PM EDT MON APR 30 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH CENTRAL NORTH
CAROLINA...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...TUESDAY THROUGH SUNDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

VAZ022>024-034-035-045-020230-
ROANOKE-BOTETOURT-ROCKBRIDGE-BEDFORD-AMHERST-CAMPBELL-
1017 PM EDT MON APR 30 2012

...DENSE FOG ADVISORY IN EFFECT UNTIL 8 AM EDT TUESDAY...

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

.DAY ONE...TONIGHT.

PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE
INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS.

   DENSE FOG ADVISORY.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE
INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS.

   DENSE FOG ADVISORY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

NCZ001>003-018>020-VAZ015-020230-
ASHE-ALLEGHANY NC-SURRY-WATAUGA-WILKES-YADKIN-GRAYSON-
1017 PM EDT MON APR 30 2012

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

.DAY ONE...TONIGHT.

THUNDERSTORMS COULD BE SEVERE BEFORE MIDNIGHT WITH LARGE HAIL AND
HEAVY RAIN. ANY ADDITIONAL THUNDERSTORMS AFTER MIDNIGHT COULD
CAUSE LOCALIZED FLOODING.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

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SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BLACKSBURG VA
258 AM EDT TUE MAY 1 2012

VAZ019-020-WVZ042>045-010800-
ALLEGHANY VA-BATH VA-GREENBRIER WV-MERCER WV-MONROE WV-SUMMERS WV-
258 AM EDT TUE MAY 1 2012

...STRONG THUNDERSTORMS WILL AFFECT ALLEGHANY...BATH...GREENBRIER...
MERCER...MONROE AND SUMMERS COUNTIES...

AT 250 AM EDT...STRONG THUNDERSTORMS WERE ALONG A LINE FROM MARLINTON
WEST VIRGINIA...TO 20 MILES WEST OF BLUEFIELD WEST VIRGINIA...MOVING
SOUTHEAST AT 30 MPH.

WIND GUSTS TO 30 MPH AND PEA-SIZED HAIL ARE POSSIBLE WITH THESE
STORMS.

THESE STORMS WILL BE NEAR JUMPING BRANCH...HIX...HINTON...AND RORER
AROUND 300 AM...CAMP CREEK STATE PARK...BLUESTONE DAM...BLUESTONE
STATE PARK...AND LEWISBURG AROUND 315 AM AND BLUEFIELD...WARM
SPRINGS...COVINGTON AND UNION BETWEEN 330 AND 400 AM.

LAT...LON 3819 7952 3816 7952 3817 7947 3777 7996
      3725 8121 3734 8137 3746 8131 3758 8119
      3761 8108 3772 8098 3770 8090 3782 8094
      3788 8076 3793 8081 3818 8036 3811 8035
      3804 8021 3807 7997 3818 7992 3827 7981

PEM

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BLACKSBURG VA
258 AM EDT TUE MAY 1 2012

VAZ011-WVZ042>045-010800-
GILES VA-GREENBRIER WV-MERCER WV-MONROE WV-SUMMERS WV-
258 AM EDT TUE MAY 1 2012

...STRONG THUNDERSTORMS WILL AFFECT GILES...GREENBRIER...MERCER...
MONROE AND SUMMERS COUNTIES...

AT 256 AM EDT...STRONG THUNDERSTORMS WERE ALONG A LINE FROM 5 MILES
SOUTH OF BECKLEY TO 9 MILES WEST OF MATOAKA...MOVING EAST AT 40 MPH.

WIND GUSTS TO 40 MPH AND SMALL HAIL ARE POSSIBLE WITH THESE STORMS.

THESE STORMS WILL BE NEAR WENONAH...MATOAKA...FLAT TOP...AND MONTCALM
AROUND 310 AM...CAMP CREEK STATE PARK...JUMPING BRANCH...AND SANDLICK
AROUND 315 AM...SANDSTONE...JUMPING BRANCH AND AND ELLISON AROUND 320
AM.

LAT...LON 3769 8029 3728 8094 3736 8136 3741 8133
      3742 8129 3746 8131 3752 8122 3758 8119
      3761 8108 3764 8107 3772 8098 3770 8090
      3774 8093 3778 8090 3782 8094 3785 8089

RCS

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BLACKSBURG VA
301 AM EDT TUE MAY 1 2012

WVZ042>044-010800-
MERCER WV-MONROE WV-SUMMERS WV-
301 AM EDT TUE MAY 1 2012

...STRONG THUNDERSTORMS WILL AFFECT MERCER...MONROE AND SUMMERS
COUNTIES...

AT 256 AM EDT...STRONG THUNDERSTORMS WERE ALONG A LINE FROM 5 MILES
SOUTH OF BECKLEY TO 9 MILES WEST OF MATOAKA...MOVING EAST AT 40 MPH.

WIND GUSTS TO 40 MPH AND SMALL HAIL ARE POSSIBLE WITH THESE STORMS.

THESE STORMS WILL BE NEAR WENONAH...MATOAKA...FLAT TOP...AND MONTCALM
AROUND 310 AM...CAMP CREEK STATE PARK...JUMPING BRANCH...AND SANDLICK
AROUND 315 AM...SANDSTONE...JUMPING BRANCH AND AND ELLISON AROUND 320
AM.

LAT...LON 3781 8072 3772 8064 3768 8045 3772 8040
      3769 8038 3769 8029 3738 8078 3743 8086
      3735 8085 3730 8095 3736 8136 3742 8129
      3746 8131 3752 8122 3758 8119 3761 8108
      3772 8098 3770 8090 3782 8094 3785 8089

RCS