Severe Thunderstorm Warning 688, NWS Greenville-Spartanburg, SC

664 
WWUS52 KGSP 262149
SVSGSP

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
549 PM EDT MON SEP 26 2011

NCC179-262215-
/O.CON.KGSP.SV.W.0688.000000T0000Z-110926T2215Z/
UNION NC-
549 PM EDT MON SEP 26 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 615 PM EDT
FOR UNION COUNTY IN THE PIEDMONT OF NORTH CAROLINA...

AT 547 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A SEVERE THUNDERSTORM CAPABLE OF PRODUCING QUARTER SIZE
HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH.  THIS STORM WAS
LOCATED 8 MILES SOUTHWEST OF TRINITY...OR 9 MILES NORTHEAST OF
LANCASTER...MOVING NORTH AT 5 MPH.

* LOCATIONS IMPACTED INCLUDE...
  TRINITY AND MINERAL SPRINGS...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

PEOPLE IN THE PATH OF THIS STORM SHOULD BE ALERT FOR LARGE HAIL AND
DAMAGING WINDS. FREQUENT LIGHTNING AND LOCALLY HEAVY RAIN CAN OCCUR
WITH ANY THUNDERSTORM. SEEK SHELTER INDOORS AWAY FROM WINDOWS AND
DOORS UNTIL THE STORM PASSES.

&&

LAT...LON 3488 8030 3482 8031 3481 8032 3481 8079
      3482 8081 3520 8056 3521 8055 3517 8046
      3517 8039 3518 8037 3517 8035 3520 8028
TIME...MOT...LOC 2149Z 178DEG 6KT 3479 8064

$$

RWH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
240 PM EDT MON SEP 26 2011

.SYNOPSIS...
A COLD FRONT WILL CROSS THE CAROLINAS AND NORTHEAST GEORGIA THROUGH
THE OVERNIGHT AND REACH THE EAST COAST ON TUESDAY. A STRONGER COLD
FRONT WILL PUSH ACROSS THE REGION ON FRIDAY AND BRING A COOLER AND DRIER
CANADIAN AIR MASS IN FOR THE WEEKEND.

&&

.NEAR TERM /THROUGH TUESDAY/...
AT 130 PM EDT MONDAY...THE CLOSED UPPER LOW OVER THE MIDWEST WILL
PERSIST THROUGH TUESDAY. A COLD FRONT WILL APPROACH THE MOUNTAINS
FROM THE WEST EARLY THIS AFTERNOON...CROSSING OUR AREA TONIGHT.
SOUTHEASTERLY ISENTROPIC UPGLIDE AND UPSLOPE FLOW WILL GRADUALLY
DIMINISH THIS EVENING...BUT INSTABILITY AND CONVERGENCE AHEAD OF THE
FRONT WILL PROMOTE CONVECTIVE DEVELOPMENT. WHILE SHEAR IS NOT
TREMENDOUS...DRY AIR ALOFT SUPPORT GUSTY WINDS WITH THE STRONGEST
THUNDERSTORMS. POPS AND PRECIPITATION AMOUNTS WILL BE SOMEWHAT
LIMITED AS HTE BEST GULF INFLOW MOVES EAST OF OUR AREA BEFORE THE
FRONT ARRIVES. ISOLATED HYDROLOGIC PROBLEMS REMAIN A POSSIBILITY IN
AREAS THAT HAVE HAD SUBSTANTIAL PRECIPITATION RECENTLY...IF HEAVY
RAINFALL RESULTS FROM CONVECTION THERE. MINIMUM TEMPERATURES WILL BE
SEVERAL CATEGORIES ABOVE NORMAL UNDER CLOUD COVER WITH LIGHT
SOUTHERLY WINDS. PRECIPITATION DECREASES TUESDAY AS THE FRONT MOVES
EAST. MAXIMUMS TEMPERATURES WILL BE ABOVE NORMAL AS CLOUD COVER
ERODES AND ONLY WEAK COLD ADVECTION TAKES PLACE.

&&

.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
AS OF 150 PM MONDAY...THE UPPER LOW CONTINUES TO BE CUTOFF FROM
WESTERLY FLOW ON WED AND AN OCCLUDED SFC FRONT WILL REMAIN TO THE
SOUTH OF THE CWFA. GOOD AGREEMENT IS HAD IN THE MODELS WRT TO THE
UPPER LEVEL FEATURES...HOWEVER THE HANDLING OF THE SFC FRONT IS NOT
SO CERTAIN. WITH THE 12Z NAM IS FURTHER NORTH WITH THE
FRONT...BASICALLY ACROSS THE SC MIDLANDS TUE...AND THE GFS KEEPING
IT SHUNTED OVER THE LOW COUNTRY. POPS WERE THEREFORE ADJUSTED VERY
LITTLE AND IF ANYTHING TAKEN DOWN A COUPLE PERCENT ACROSS THE
UPSTATE. STILL...ONLY SLIGHT CHANCES AND ONLY ACROSS THE EXTREME SRN
ZONES.

THERE SHOULD BE SOME DEGREE OF LOW END MTN INTERACTION WITH THE
UPPER LOW AS IT STRETCHES SOUTH AND FINALLY PULLS NE THU...BUT WITH
LIMITED MOISTURE AND AN OVERALL LARGE SCALE SUBSIDENCE ZONE MOVING
INTO THE REGION...POPS WERE AGAIN CHANGED LITTLE AND LEFT AS SLIGHT.
ALSO...GIVEN THE POOR PERFORMANCE OF THE MODELS WITH THE CUTOFF LOW
AND IT/S SENSIBLE WX CONNECTION THE PAST SEVERAL DAYS...THERE IS LOW
CONFIDENCE IN THE DEGREE AND TYPE OF STORM ACTIVITY THAT MAY
PREVAIL. RIGHT NOW...WILL COUNT ON MAINLY RAIN SHOWERS WITH PERHAPS
AN ISOL TSTM OR TWO. SBCAPE VALUES ARE VERY LOW TUE AND CAPPED OFF
SHALLOW WED DUE TO THE SUB INVERSION. MAX TEMPS STILL LOOK WARM WED
WITH GOOD INSOLATION EXPECTED AREA WIDE AND A DEEPENING S/LY FLOW.
ON THU...MAXES WILL AGAIN BE ABOVE NORMAL WITH W/LY LLVL FLOW
CONTRIBUTING A WARMING DOWNSLOPE COMPONENT.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 230 PM MONDAY...MODELS STILL IN GOOD AGREEMENT SHOWING A
SHORTWAVE TROF DIGGING SE ALONG THE W EDGE OF THE MEAN TROF OVER THE
E US THU NIGHT. AN ASSOC COLD FRONT WILL PUSH QUICKLY SE ACROSS THE
AREA EARLY FRI. WITH A DRY AIRMASS IN PLACE AND LITTLE MOISTURE WITH
THE SYSTEM...EXPECT JUST SLIGHT CHC POPS OVER MAINLY THE N MTNS.
HIGHS FRI WILL BE WITHIN A DEG OR TWO OF AVG.

BEHIND THE FRONT A MUCH COOLER CANADIAN AIRMASS WILL DROP S ACROSS
THE REGION AND TEMPS WILL TAKE A TUMBLE AS THKNS VALUES FALL. HIGHS
WILL TOP OUT ABOUT 10 DEG BELOW AVG SAT AFTN WITH LOWS SAT NIGHT ALSO
ABOUT 10 DEG BELOW AVG. TEMPS SUN-MON WILL BE WELL BELOW AVG AS WELL
AND FROST AT SOME OF THE HIGHER ELEVATIONS...MAINLY RIDGETOPS...CAN
BE EXPECTED.

&&

.AVIATION /19Z MONDAY THROUGH SATURDAY/...
AT KCLT...VFR IS EXPECTED TO RETURN THIS AFTERNOON AS LOW LEVEL
ISENTROPIC UPGLIDE DECREASES ON WINDS THAT VEER FROM SE TO SW.
INSTABILITY WILL BE AVAILABLE FOR SCATTERED CONVECTION THIS
AFTERNOON AND EVENING...BUT CONFIDENCE IN TIMING AND LOCATION IS TOO
LOW FOR ANY MORE THAN CB AT THIS POINT. GUIDANCE CONSENSUS KEEPS
VSBY VFR AT TAF SITES OVERNIGHT...BUT TAKES CIGS TO VLIFR BY
DAYBREAK. WILL TAKE CIG TO IFR AS A STEP IN THAT DIRECTION...BUT NOT
LOWER UNTIL CONFIDENCE IMPROVES. RAPID IMPROVEMENT IS EXPECTED IN
DRIER AIR BEHIND A COLD FRONT ON TUESDAY MORNING.

ELSEWHERE...EXPECT VFR TO RETURN THIS AFTERNOON AS UPSLOPE FLOW AD
ISENTROPIC UPGLIDE END WITH LOW LEVEL FLOW VEERING FROM SE TO SW.
INSTABILITY AND CONVERGENCE AHEAD OF AN APPROACHING FRONT WILL
SUPPORT SCATTERED CONVECTION...BUT NOT OF SUFFICIENT COVERAGE TO
WARRANT MORE THAN A MENTION OF CB IN THE TAFS. LATE TONIGHT THE
GUIDANCE CONSENSUS BRINGS MOST SITE TO VLIFR ON CIGS...BUT KEEPS
VSBY VFR. CONFIDENCE IS TOO LOW TO GO THAT PESSIMISTIC...AND ONLY
IFR WILL BE CARRIED BEFORE DAWN. DRIER AIR BEHIND A FRONTAL PASSAGE
WILL BRING RAPID IMPROVEMENT TUESDAY MORNING.

OUTLOOK....A SLOW AND STEADY DRYING TREND IS INDICATED FROM TUESDAY
ONWARD THIS WEEK. ANOTHER COLD FRONT WILL ARRIVE FROM THE NW FRIDAY.

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...SBK
NEAR TERM...JAT
SHORT TERM...SBK
LONG TERM...RB
AVIATION...JAT

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
146 PM EDT MON SEP 26 2011

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-271800-
RABUN-HABERSHAM-STEPHENS-FRANKLIN-HART-ELBERT-AVERY-ALEXANDER-
IREDELL-DAVIE-MADISON-YANCEY-MITCHELL-SWAIN-HAYWOOD-BUNCOMBE-CATAWBA-
ROWAN-GRAHAM-NORTHERN JACKSON-MACON-SOUTHERN JACKSON-TRANSYLVANIA-
HENDERSON-CLEVELAND-LINCOLN-GASTON-MECKLENBURG-CABARRUS-UNION NC-
CALDWELL MOUNTAINS-GREATER CALDWELL-BURKE MOUNTAINS-GREATER BURKE-
MCDOWELL MOUNTAINS-EASTERN MCDOWELL-RUTHERFORD MOUNTAINS-
GREATER RUTHERFORD-POLK MOUNTAINS-EASTERN POLK-OCONEE MOUNTAINS-
PICKENS MOUNTAINS-GREENVILLE MOUNTAINS-GREATER OCONEE-
GREATER PICKENS-GREATER GREENVILLE-SPARTANBURG-CHEROKEE-YORK-
ANDERSON-ABBEVILLE-LAURENS-UNION SC-CHESTER-GREENWOOD-
146 PM EDT MON SEP 26 2011

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

.DAY ONE...THIS AFTERNOON AND TONIGHT.

SCATTERED TO NUMEROUS THUNDERSTORMS WILL DEVELOP ALONG AND AHEAD
OF AN APPROACHING COLD FRONT THIS AFTERNOON AND EVENING. THESE
THUNDERSTORMS WILL LIKELY PRODUCE CLOUD TO GROUND LIGHTNING AND
HEAVY DOWNPOURS. SEVERAL OF THESE STORMS MAY ALSO BECOME
SEVERE...PRODUCING DAMAGING WIND GUSTS AND LARGE HAIL.

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

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.

07