Severe Thunderstorm Warning 107, NWS Greenville-Spartanburg, SC

173 
WWUS52 KGSP 261248
SVSGSP

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
848 AM EDT THU APR 26 2012

NCC011-121-199-261315-
/O.CON.KGSP.SV.W.0107.000000T0000Z-120426T1315Z/
AVERY NC-MITCHELL NC-YANCEY NC-
848 AM EDT THU APR 26 2012

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT FOR YANCEY...
MITCHELL AND AVERY COUNTIES UNTIL 915 AM EDT...

AT 839 AM EDT...DOPPLER RADAR INDICATED A LINE OF SEVERE
THUNDERSTORMS WITH A HISTORY OF PRODUCING DAMAGING WINDS IN EXCESS OF
60 MPH.  THESE STORMS WERE LOCATED ALONG A LINE EXTENDING FROM 16
MILES NORTH OF ELIZABETHTON TO HAMPTON TO 5 MILES NORTHEAST OF
BARNARDSVILLE...MOVING EAST AT 60 MPH.

SEVERE THUNDERSTORMS WILL IMPACT LOCATIONS NEAR...
  SPRUCE PINE...NEWLAND...INGALLS AND BANNER ELK.
  LINVILLE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TO REPORT DAMAGING WINDS...HAIL...OR FLOODING THROUGH OUR AUTOMATED
REPORTING SYSTEM...CALL TOLL FREE...1 8 7 7...6 3 3...6 7 7 2.

&&

LAT...LON 3628 8189 3621 8190 3606 8174 3596 8181
      3600 8190 3589 8199 3583 8213 3570 8226
      3575 8234 3582 8235 3582 8241 3600 8240
      3612 8232 3617 8221 3615 8215 3611 8212
      3611 8208 3613 8203 3629 8192
TIME...MOT...LOC 1248Z 280DEG 52KT 3654 8198 3619 8203
          3579 8222

$$

CSH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
706 AM EDT THU APR 26 2012

.SYNOPSIS...
A COLD FRONT WILL APPROACH THE AREA FROM THE NORTH RESULTING IN
UNSETTLED WEATHER TODAY. THIS COLD FRONT IS EXPECTED TO BECOME
STATIONARY FROM WEST TO EAST ACROSS OUR AREA FRIDAY AND SATURDAY.
THE FRONT WILL MOVE OFF TO THE SOUTH SUNDAY AS CANADIAN HIGH BUILDS
OVER THE REGION. THEN THE HIGH WILL LINGER THROUGH EARLY PART OF
NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 7 AM...A WELL ORGANIZED BOW ECHO WILL SWEEP INTO THE WESTERN
NC MTNS AROUND 8AM AND WILL REMAIN UNTIL 10AM. THIS LINE WILL BRING
A RISK OF DAMAGING WINDS AND HAIL...SPS HAS BEEN ISSUED. I WILL RAMP
UP POPS AND MENTION SVR TSRA IN THE FORECAST. ELSEWHERE...WINDS
CONTINUE TO REMAIN ABOVE GUIDANCE...I HAVE INCREASED EARLY MORNING
WINDS SOUTH OF THE WARM FRONT. NORTH OF THE FRONT...I WILL ADD THE
MENTION OF FOG.

AS OF 4 AM...THE SFC WARM FRONT WAS LOCATED GENERALLY ACROSS THE NRN
MTNS EAST ALONG THE I-40 CORRIDOR. THE FRONT IS EXPECTED TO MOVE
NORTH OF THE CWA BY SUNRISE. OBS SOUTH OF THE FRONT SHOW VERY MILD
TEMPERATURES...IN THE U50S ACROSS THE MTNS VALLEYS TO MID TO U60S
EAST. THESE TEMPERATURES MAY COOL A COUPLE OF DEGREES BEFORE
SUNRISE...MAINLY DUE TO DECREASING MID TO HIGH CLOUD COVER. A FEW
SPOTS WITH THE MTN VALLEYS COULD SEE FOG EARLY THIS MORNING.
OTHERWISE...MOST SITES WILL SEE SW WINDS GRADUALLY STRENGTHEN
THROUGH SUNRISE...MARGINAL GUSTS POSSIBLE ACROSS NE GA AND SC EAST
OF I-85.

A MCS WAS OVER WESTERN KY AND TRACKING SE AT 8Z...IF THE MCS
SURVIVES...IT WOULD REACH THE EXTREME WESTERN NC MTNS BETWEEN 13Z TO
14Z. I WILL KEEP POPS LOW THROUGH SUNRISE...THEN BEGIN TO INCREASE
POPS TO CHC ACROSS THE MTNS FOR SHRA/TSRA BY 14Z. BY MID MORNING...THE
CENTER OF THE CLIPPER IS FORECAST TO REACH THE NRN OHIO RIVER VALLEY
AS HIGH PRESSURE REMAINS ACROSS FL. THE PRESSURE GRADIENT SHOULD
RANGE BETWEEN 4 TO 6 MBS BY MID MORNING...RELAXING A MB OR TWO
DURING THE AFTERNOON. MIXING TO 4 TO 5 KFT SHOULD RESULT IN GUSTY SW
WINDS FROM 15Z THROUGH SUNSET...GUSTING TO 20 TO 25 KTS...A LITTLE
STRONGER OVER THE SC UPSTATE. HIGH TEMPS ARE FORECAST TO RANGE FROM
THE MID 70S ACROSS THE MTN VALLEYS TO LOW TO MID 80S EAST.

ANY CONVECTION SHOULD REMAIN ACROSS THE NC MTNS THROUGH MID DAY.
HOWEVER...THE COLD FRONT ASSOCIATED WITH THE CLIPPER IS FORECAST TO
SWEEP ACROSS THE SOUTHERN APPALACHIANS LATE THIS AFTERNOON. THROUGH
THE EVENING HOURS...THE SW TO NE FRONT MAY PUSH EAST OVER THE
FOOTHILLS AND PIEDMONT. FORECAST SOUNDINGS ACROSS THE CWA THIS
MORNING INDICATE A SIGNIFICANT H8 INVERSION. THIS INVERSION SHOULD
KEEP THE FOOTHILLS AND PIEDMONT CAPPED THROUGH MUCH OF THE DAY.
ACROSS THE MTNS...THE VALUES OF CIN ASSOCIATED WITH THE INVERSION IS
LESS...AND THE POTENTIAL FOR UPSTREAM CONVECTION TRACKING ACROSS THE
MTNS IS CERTAINLY POSSIBLE. I WILL KEEP CHC POPS OVER THE MTNS AND
SCHC OR LESS POPS EAST THROUGH 20Z. INTO THE EARLY EVENING
HOURS...THE APPROACH OF THE COLD FRONT WILL WEAKEN THE INVERSION AND
CONVECTION SHOULD GRADUALLY DEVELOP ALONG AND AHEAD OF THE FRONT. I
WILL INCREASE POPS TO LIKELY ACROSS THE TN BORDER COUNTIES AND
INDICATE SCT POPS EAST. FORECAST SOUNDINGS ACROSS THE MTNS INDICATE
THAT LLVL HELICITY WILL INCREASE TO AROUND 200 M2/S2...EHI ABOVE
2...AND SWEAT CLOSE TO 400. THE SHEAR COMBINED WITH SFC BASED CAPES
AROUND 2K J/KG AND WBZ AROUND 7.5 KFT SHOULD FAVOR THE DEVELOPMENT
OF SVR TS...ESPECIALLY ALONG THE TN LINE. SPC OUTLOOKS THIS AREA
WITH A SLIGHT RISK...HIGHLIGHTING THE POSSIBILITY OF SVR HAIL AND
WIND. WE WILL CONTINUE TO MENTION THE THREAT OF SVR TSRA ACROSS THE
NC MTNS IN THE HWO.

TONIGHT...CONVECTION WILL GRADUALLY ASHE OUT AROUND
MIDNIGHT...LIKELY LEAVING ISO SHRA AND TSRA NEAR THE GA/SC/NC
INTERSECTION INTO THE EARLY MORNING HOURS. NAM AND GFS INDICATE THAT
COOLER THICKNESSES WILL SLOWLY PUSH SOUTH ACROSS THE REGION
OVERNIGHT. USING A BLEND OF MOS...LOW TEMPERATURES ARE EXPECTED TO
RANGE FROM THE L50S ACROSS THE MTNS TO NEAR 60 ACROSS THE UPPER
SAVANNAH RIVER VALLEY.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
AS OF 330 AM THURSDAY...THE SHORT TERM FORECAST PICKS UP AT 12Z ON
FRIDAY WITH THE EASTERN CONUS UPPER TROF SLOWLY LIFTING NE AND THE
SOUTHERN STREAM BECOMES FAIRLY ZONAL. A WEAK UPPER RIDGING WILL
BUILD INTO THE SOUTHEAST U.S. SATURDAY AND ANOTHER UPPER TROF OVER
QUEBEC DIGS SOUTH BY EARLY SUNDAY.

AT THE SURFACE...A LOW PRESSURE WILL MOVE OFF THE NEW ENGLAND COAST
THURSDAY NIGHT/EARLY FRIDAY...AND DRAG A COLD FRONT SOUTHWARD INTO
OUR AREA. THE LATEST MODELS CONTINUE TO INDICATE THAT THE FRONT
BECOMES STATIONARY INVOF THE SOUTHERN EDGE OF THE CWA BY 12Z FRIDAY.
THEN THE FRONT WILL LIFT BACK NORTHWARD BY FRIDAY AFTERNOON. THE
LATEST MODEL SOUNDINGS HAVE TRENDED WEAKER WIND SHEAR AND LESS CAPE
VALUES THAN THE PREVIOUS RUNS. NEVERTHELESS...WITH SOME DEGREE OF
CONVERGENCE AND WEAK DIURNAL INSTABILITY...WE COULD SEE A
DEVELOPMENT OF SHOWERS AND THUNDERSTORMS ALONG THE FRONTAL BOUNDARY.
A MODEL BLEND FOR POPS RESULTS IN SOLID CHANCE POP WORKING FROM SW
TO NE DURING THE DAY AND INTO FRIDAY EVENING. THE FRONT WILL LIFT
NORTH OF THE AREA SATURDAY AS THE SUBTROPICAL HIGH BUILDS OVER THE
SOUTHEAST U.S. THE FRONT WILL REMAIN JUST TO OUR NORTH KEEPING OUR
WEATHER MOSTLY DRY AND WARMER TEMPS.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
AS OF 230 AM THURSDAY...THE MEDIUM RANGE FORECAST PICKS UP AT 12Z ON
SUNDAY WITH WEAK UPPER RIDGING OVER THE CAROLINAS AND AN UPPER TROF
PERSISTING OVER THE NORTHEASTERN STATES. HEIGHTS BEGIN TO RISE
MONDAY AS THE UPPER TROF ROTATES OFF THE NEW ENGLAND COAST AND UPPER
RIDGING BUILDS INTO THE SOUTHEAST U.S. BY EARLY NEXT WEEK.

AT THE SURFACE...BOTH THE HPC AND THE GFS INDICATE THAT CANADIAN
SURFACE HIGH OVER THE GREAT LAKES AND NORTHEAST STATES WILL PUSH A
BACKDOOR COLD FRONT SOUTH ACROSS OUR FORECAST AREA ON SUNDAY. IN THE
WAKE OF THE FRONTAL PASSAGE...COLD AIR DAMMING IS EXPECTED FOR
SUNDAY NIGHT AND MONDAY. WITH DECENT MOISTURE AND WEAK LLVL
FORCING...HAVE MENTIONED SLIGHT CHANCE POP OVER THE PIEDMONT AND
SOLID CHANCE FOR NC MOUNTAINS AND FOOTHILLS. THE CONTINENTAL HIGH
BECOMES SUBTROPICAL HIGH AND REMAINS OVER THE SOUTHEAST U.S. TUE/WED
KEEPING A FRONTAL SYSTEM WELL TO OUR NORTH DURING THE PERIOD.
HOWEVER...WE CANNOT RULE OUT THE POSSIBILITY OF AFTERNOON SHOWERS
AND THUNDERSTORMS TUE/WED DUE TO INCREASING MOIST SOUTHERLY FLOW AND
DIURNAL INSTABILITY. DAYTIME TEMPS WILL BE A FEW DEGREES BELOW
NORMAL MON/TUE...THEN BACK ABOVE NORMAL WEDNESDAY.

&&

.AVIATION /11Z THURSDAY THROUGH MONDAY/...
AT KCLT...WINDS WILL REMAIN SSW AS A WARM FRONT MOVES NORTH. SW
WINDS ACROSS THE TERMINAL THIS MORNING WILL GRADUALLY STRENGTHEN
FROM THE PRE DAWN HOURS ON. A 4 TO 6 MB PRESSURE GRADIENT MAY
DEVELOP BY MID MORNING AS THE CENTER OF THE CLIPPER LOW MOVES OVER
THE OHIO RIVER VALLEY. MIXING TO 4 TO 5 KFT SHOULD RESULT IN GUSTY
SW WINDS FROM 14Z THROUGH SUNSET...GUSTING TO 20 TO 25 KTS. A COLD
FRONT ASSOCIATED WITH THE CLIPPER WILL PUSH NW TO SE ACROSS THE
REGION DURING THE LATE AFTERNOON TO EARLY EVENING HOURS. SHRA AND
TSRA SHOULD DEVELOP ALONG AND AHEAD OF THE FRONT...COVERAGE APPEAR
TOO LITTLE AT THIS POINT TO ADD TO THE TAF. WINDS SHOULD DECOUPLE
AND VEER NW AFTER 0Z.

ELSEWHERE...FOG AND LOW CLOUDS WILL REMAIN OVER KHKY THROUGH
13Z...THEN THE WARM FRONT SHOULD LIFT NORTH. SW WINDS ACROSS THE
TERMINAL THIS MORNING WILL GRADUALLY STRENGTHEN FROM THE PRE DAWN
HOURS ON. A BAND OF SHRA/TSRA MAY REACH KAVL AROUND 14Z. A 4 TO 6 MB
PRESSURE GRADIENT MAY DEVELOP BY MID MORNING AS THE CENTER OF THE
CLIPPER LOW MOVES OVER THE OHIO RIVER VALLEY. MIXING TO 4 TO 5 KFT
SHOULD RESULT IN GUSTY SW WINDS FROM 14Z THROUGH SUNSET...GUSTING TO
20 TO 25 KTS...A LITTLE STRONGER OVER THE SC UPSTATE. A COLD FRONT
ASSOCIATED WITH THE CLIPPER WILL PUSH NW TO SE ACROSS THE REGION
DURING THE LATE AFTERNOON TO EARLY EVENING HOURS. SHRA AND TSRA
SHOULD DEVELOP ALONG AND AHEAD OF THE FRONT. WINDS SHOULD DECOUPLE
AND VEER NW AFTER 0Z.

OUTLOOK...A COLD FRONT WILL APPROACH FROM THE NORTH THROUGH FRIDAY.
MAINLY PM SHOWERS/THUNDERSTORMS AND MORE WIDESPREAD RESTRICTIONS
WILL BE POSSIBLE LATE IN THE WEEK AS THE FRONT DIPS FARTHER SOUTH
INTO THE AREA.

AN EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLE SHOWING THE
PERCENTAGE OF GUIDANCE MEMBERS AGREEING WITH THE SCHEDULED ISSUANCE
CATEGORY IS AVAILABLE AT FOLLOWING LINK (USE LOWER CASE)...

WWW.WEATHER.GOV/GSP/AVIATION/TABLES.HTM

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

SYNOPSIS...JOH
NEAR TERM...NED
SHORT TERM...JOH
LONG TERM...JOH
AVIATION...NED

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
519 AM EDT THU APR 26 2012

NCZ033-048>053-058-059-062>065-501-503-505-507-509-270930-
AVERY-MADISON-YANCEY-MITCHELL-SWAIN-HAYWOOD-BUNCOMBE-GRAHAM-
NORTHERN JACKSON-MACON-SOUTHERN JACKSON-TRANSYLVANIA-HENDERSON-
CALDWELL MOUNTAINS-BURKE MOUNTAINS-MCDOWELL MOUNTAINS-
RUTHERFORD MOUNTAINS-POLK MOUNTAINS-
519 AM EDT THU APR 26 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN NORTH CAROLINA.

.DAY ONE...TODAY AND TONIGHT.

A LINE OF ORGANIZED THUNDERSTORMS IS EXPECTED TO PUSH SOUTHEAST
ACROSS KENTUCKY AND TENNESSEE EARLY THIS MORNING. THESE STORMS
MAY REMAIN WELL ORGANIZED AS THEY REACH THE NORTH CAROLINA
MOUNTAINS AFTER SUNRISE THIS MORNING...POSSIBLY PRODUCING DAMAGING
STRAIGHT LINE WINDS AND HAIL.

A COLD FRONT MAY BRING ANOTHER ROUND OF SEVERE WEATHER TO THE
NORTH CAROLINA MOUNTAINS LATE THIS AFTERNOON AND EVENING. THE
ENVIRONMENT ALONG AND AHEAD OF THE FRONT WILL SUPPORT CLUSTERS OR
LINES OF THUNDERSTORMS TO DEVELOP ACROSS EASTERN KENTUCKY AND
TENNESSEE. THESE STORMS WILL LIKELY TRACK EAST TO SOUTHEAST
REACHING THE NORTH CAROLINA MOUNTAINS LATE THIS AFTERNOON AND
EVENING. DAMAGING WIND GUSTS AND LARGE HAIL WILL BE POSSIBLE WITH
THESE STORMS.

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

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTERS ARE REQUESTED TO FORWARD ANY REPORTS OF LARGE
HAIL...DAMAGING WINDS...TORNADOES OR FLASH FLOODING TO OUR OFFICE.

GAZ010-017-018-026-028-029-NCZ035>037-056-057-068>072-082-502-504-
506-508-510-SCZ001>014-019-270930-
RABUN-HABERSHAM-STEPHENS-FRANKLIN-HART-ELBERT-ALEXANDER-IREDELL-
DAVIE-CATAWBA-ROWAN-CLEVELAND-LINCOLN-GASTON-MECKLENBURG-CABARRUS-
UNION NC-GREATER CALDWELL-GREATER BURKE-EASTERN MCDOWELL-
GREATER RUTHERFORD-EASTERN POLK-OCONEE MOUNTAINS-PICKENS MOUNTAINS-
GREENVILLE MOUNTAINS-GREATER OCONEE-GREATER PICKENS-
GREATER GREENVILLE-SPARTANBURG-CHEROKEE-YORK-ANDERSON-ABBEVILLE-
LAURENS-UNION SC-CHESTER-GREENWOOD-
519 AM EDT THU APR 26 2012

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST GEORGIA...PIEDMONT
NORTH CAROLINA...WESTERN NORTH CAROLINA AND UPSTATE SOUTH CAROLINA.

.DAY ONE...TODAY AND TONIGHT.

SCATTERED THUNDERSTORMS ARE FORECAST TO DEVELOP ACROSS THE
FOOTHILLS AND PIEDMONT LATE THIS AFTERNOON AND EVENING. A FEW OF
THESE STORMS COULD PRODUCE QUARTER SIZED HAIL AND DAMAGING WIND GUSTS.

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

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTERS ARE REQUESTED TO FORWARD ANY REPORTS OF LARGE
HAIL...DAMAGING WINDS...TORNADOES OR FLASH FLOODING TO OUR OFFICE.

NED

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
624 AM EDT THU APR 26 2012

NCZ048-051>053-058-059-062-261400-
MADISON-SWAIN-HAYWOOD-BUNCOMBE-GRAHAM-NORTHERN JACKSON-MACON-
INCLUDING THE CITIES OF...CHEROKEE...BRYSON CITY...WAYNESVILLE...
ASHEVILLE...SYLVA...FRANKLIN
624 AM EDT THU APR 26 2012

...A LINE OF SEVERE THUNDERSTORMS MAY REACH THE WESTERN NORTH
CAROLINA MOUNTAINS THIS MORNING...

AT 620 AM...A LINE OF SEVERE THUNDERSTORMS WAS CROSSING THE MIDDLE
KENTUCKY-TENNESSEE STATE LINE. THIS LINE WAS MOVING SOUTHEAST AT
45 MPH AND IS EXPECTED TO REACH THE WESTERN NORTH CAROLINA
MOUNTAINS AROUND 8 AM. STORM REPORTS INDICATE THAT THIS LINE HAS A
LONG HISTORY OF PRODUCING LARGE HAIL AND ISOLATED DAMAGING WIND.
IF THIS LINE REMAINS ORGANIZED OVER EASTERN TENNESSEE...THEN AREAS
FROM GRAHAM TO MADISON COUNTIES AND MOUNTAIN COUNTIES EAST WOULD
LIKELY EXPERIENCE SEVERE WEATHER BETWEEN 8 AM AND 10 AM THIS
MORNING.

NED