Severe Thunderstorm Warning 416, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
150 PM EDT WED AUG 29 2007

.SYNOPSIS...
UPPER RIDGE WEAKENS TODAY AND THIS WILL ALLOW WEAK UPPER LEVEL
DISTURBANCES TO AFFECT THE AREA. A WEAK COLD FRONT WILL APPROACH
LATE THURSDAY AND PUSH SOUTH OF THE AREA FRIDAY INTO SATURDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
THERE CONTINUES TO BE AN AIXS OF VERY DRY MID LEVEL AIR OVER THE NE
PART OF THE FA...AND VERY MOIST MID-LEVEL AIR OVER THE SW PART. IN
THE MOIST AIR...A WEAK SHEAR AIXS EXTENDS FROM MIDDLE TN SSE ACROSS
WESTERN GA. THIS FEATURE HAS PIVOTED FROM A W TO E ORIENTATION TO
MORE OF A N TO S ORIENTATION OVER THE PAST DAY...BUT IT IS STILL
JUST A HAIR OUTSIDE THE FA. SO THERE CONTINUES TO BE A FAIR AMOUNT
OF SHRA/TSTM ACTIVITY TO OUR IMMEDIATE WEST...BUT VERY LITTLE IN THE
FA. THAT MAY CHANGE LATER THIS AFTN AS THE NAM...GFS AND RUC ALL
DEVELOP GOOD LLVL CONVERGENCE OVER THE SRN NC FOOTHILLS AND PIEDMONT
AND THE NRN UPSTATE. I/VE UPPED UPS TO LOW CHANCE THROUGHOUT THIS
AREA OF CONVERGENCE AS I THINK SCT CONVECTION WILL DEVELOP WITH THE
LLVL FORCING...THOUGH ONSET TIME MAY BE FAIRLY LATE...SAY AFTER 21
UTC. I ALSO RAISED MAX TEMPS A COUPLE DEGREES IN THE EASTERN
ZONES...MORE IN LINE WITH OUR LOCAL THICKNESS SCHEME.

&&

.SHORT TERM /THURSDAY THROUGH FRIDAY/...
CWFA STILL EXPECTED TO COME UNDER NW FLOW ALOFT WITHIN BACKSIDE OF
EASTERN CONUS TROUGH. THIS PATTERN SHIFT WILL ALLOW A WEAK
COLD FRONT TO SAG SE ACRS THE REGION DURING THE PERIOD. DEPICTION OF
WEAK IMPULSES ROTATING THRU TROUGH QUITE DIFFICULT TO DISCERN AND
TIME. HAVE BASED POPS ROUGHLY ON THE SREF MEASURABLE CHANCES WHICH
RESULTED IN A BUMP UP TO MORE SOLID CHANCE THURSDAY AND AN ADDITION
OF SLIGHT CHANCE POPS ACRS THE EASTERN ZONES. WITH INSTABILITY SLOW
TO WANE AND BOTH THE 29/00 UTC OP GFS/NAM SOLUTIONS DEPICTING
INCREASED LAYER RH...ESPECIALLY IN THE MTNS...HAVE OPTED TO KEEP LOW
AND/OR SLIGHT CHANCE POPS GOING INTO THE OVERNIGHT HOURS ON
THURSDAY. ENOUGH SHORT RANGE MODEL AGREEMENT EXISTS WITH RESPECT TO
FRONTAL POSITIONING ON FRIDAY...FCST TO BE SOUTH OF THE CWFA. HAVE
MY DOUBTS THOUGH THAT THE POST FRONTAL AIRMASS AND EASTERLY FLOW
THAT WE WILL FIND OURSELVES UNDER INITIALLY WILL BE ENOUGH FOR ANY
APPRECIABLE AIRMASS CHANGE AND WILL CONTINUE THE ABOVE NORMAL FCST
THROUGH THE END OF THE WORKWEEK. DESPITE BEST SFC CONVERGENCE
DEVELOPING OFF TO OUR SOUTH...TSTM CHANCES WILL CONTINUE REGIONWIDE
WITH BEST CHANCES NEAR THE HIGHER TERRAIN WITHIN THE UPSLOPE FLOW.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
SAT...BOTH THE GFS AND NAM CONTINUE TO SHOW RICH MOISTURE ACROSS THE
SOUTHERN APPALACHIANS. THE GFS MOISTURE IS MAINLY ASSOCIATED WITH
LINGERING MOISTURE FROM AN OLD FRONTAL BOUNDARY. WHILE THE NAM SHOWS
A STEADY MOISTURE FEED FROM THE GULF DUE TO THE FORMATION OF A
GULF LOW NEAR THE MISSISSIPPI DELTA. GIVEN THE MOISTURE ON BOTH
MODELS AND HPC GUIDANCE...I WILL KEEP CHC POPS ACROSS THE CWA.

SUN...SFC HIGH PRESSURE MOVES OFF THE COAST OF THE MID
ATLANTIC...RESULTING IN AN LIGHT UPSLOPE H85 WIND AND NE SFC WIND.
INSTABILITY ACROSS THE CWA REMAINS FAIRLY LOW DURING THE AFTERNOON.
HOWEVER...THE EXTREME WESTERN PORTION OF NC MAY SEE LI/S FALL TO -1
TO -2. I WILL PAINT CHC TO SCHC POPS ACROSS A SMALL PORTION OF THE
NC MTNS.

MON THROUGH WED...H5 RIDGE MAKE A MODEST RETURN TO THE SE U.S.
YIELDING A SHALLOW INVERSION AROUND H7. AT THE SFC...HIGH PRESSURE
WILL REMAIN THE DOMINATE FEATURE WITH FAIRLY LOW DEWPOINTS. FORECAST
SOUNDINGS SHOW VERY LITTLE INSTABILITY GAINS EACH AFTERNOON. I WILL
USE HPC POPS AND ADVERTISE DRY CONDITIONS. IN
ADDITION...TEMPERATURES SHOULD AGAIN A FEW DEGREES FROM THE
WEEKEND.

&&

.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
AS OF 147 PM EDT...LOOKING FOR SW FLOW OVER THE UPSTATE WITH
GENERALLY LIGHT WINDS OVER NC ALONG A TROF AXIS THIS AFTN. BEST
CONVECTIVE CHANCES WILL BE JUST SOUTH OF THE TROF...ALONG A LINE
FROM KAVL TO KGSP...AND I HAVE VCTS AND VCSH IN AT THESE SITES
RESPECTIVELY. LAST NIGHT KAVL DIDN/T GO DOWN AS MUCH AS EXPECTED
BECAUSE OF CLOUD COVER. IF THE AIRPORT DOESN/T SEE ANY RAIN THIS
EVENING...CONDITIONS WILL BE SIMILAR TO LAST NIGHT. HOWEVER...IF
THEY DO SEE RAIN...THEN CIGS/VSBYS SHOULD GO DOWN DRAMATICALLY
OVERNIGHT. IF THE NAM TURNS OUT TO BE RIGHT...THERE IS A CHANCE OF
LOW CIGS DEVELOPING LATE TNGT AT CLT NORTH OF THE TROF. I DON/T HAVE
THAT IN THE TAF...BUT IT IS SOMETHING TO WATCH. WINDS LOOK TO BE E
TO NE MOST AREAS TOMORROW. THUNDER CHANCES LOOK PRETTY GOOD IN THE
AFTN...BUT NOT HIGH ENOUGH TO INCLUDE IN THE OUTLOOK PERIOD.

AVIATION OUTLOOK...THRU MON. SCT TSTMS POSSIBLE VCNTY KAVL FRI...AND
AT ALL SITES SAT AS A FRONT SLOWLY MOVES ACROSS THE REGION. THE
FRONT WILL MOVE SOUTH OF THE AREA SUNDAY...AND MON AND TUE SHOULD BE
DRY. EXPECT TYPICAL MVFR MORNING FOG AND HAZE...WITH IFR PSBL AT
KAVL. LESS FOG AND HAZE IS EXPECTED IN THE DRIER BEHIND THE FRONT
EARLY NEXT WEEK.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...AIR QUALITY ACTION DAY UNTIL 9 PM EDT THIS EVENING FOR NCZ036-
     057-069>072-082.
SC...NONE.

&&

SYNOPSIS...RB
NEAR TERM...MCAVOY
SHORT TERM...CSH
LONG TERM...NED
AVIATION...MCAVOY

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
613 AM EDT WED AUG 29 2007

GAZ010-017-018-026-028-029-NCZ033-035-048>053-056-058-059-062>065-
068-501>510-SCZ001>008-010>013-019-301015-
RABUN-HABERSHAM-STEPHENS-FRANKLIN-HART-ELBERT-AVERY-ALEXANDER-
MADISON-YANCEY-MITCHELL-SWAIN-HAYWOOD-BUNCOMBE-CATAWBA-GRAHAM-
NORTHERN JACKSON-MACON-SOUTHERN JACKSON-TRANSYLVANIA-HENDERSON-
CLEVELAND-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-ANDERSON-ABBEVILLE-LAURENS-UNION SC-GREENWOOD-
613 AM EDT WED AUG 29 2007

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

.DAY ONE...TODAY AND TONIGHT

ISOLATED TO SCATTERED THUNDERSTORMS WILL BE SEEN AGAIN TODAY.
LOCALLY STRONG STORMS WILL BE POSSIBLE...PRODUCING HEAVY RAIN...
FREQUENT CLOUD TO GROUND LIGHTNING...AND PERHAPS SOME HAIL AND/OR
GUSTY WIND.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

NCZ036-057-069>072-082-301015-
IREDELL-ROWAN-LINCOLN-GASTON-MECKLENBURG-CABARRUS-UNION NC-
613 AM EDT WED AUG 29 2007

...AIR QUALITY ACTION DAY IN EFFECT UNTIL 9 PM EDT THIS EVENING...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PIEDMONT NORTH CAROLINA.

.DAY ONE...TODAY AND TONIGHT

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

   AIR QUALITY ACTION DAY.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

NCZ037-SCZ009-014-301015-
DAVIE-YORK-CHESTER-
613 AM EDT WED AUG 29 2007

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

.DAY ONE...TODAY AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY

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 GREENVILLE-SPARTANBURG SC
149 PM EDT WED AUG 29 2007

NCZ068-SCZ008-291830-
CHEROKEE-CLEVELAND-
149 PM EDT WED AUG 29 2007

...A STRONG THUNDERSTORM WILL AFFECT NORTHEASTERN CHEROKEE AND
SOUTHERN CLEVELAND COUNTIES THROUGH 230 PM EDT...

AT 149 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 3 MILES SOUTHWEST OF SHELBY...MOVING SOUTH AT 10
MPH.

* OTHER LOCATIONS AFFECTED INCLUDE BUT ARE NOT LIMITED TO SHELBY...
  PATTERSON SPRINGS...GROVER...EARL...BOILING SPRINGS NC AND
  BLACKSBURG.

HEAVY RAINFALL...AND WIND GUSTS OF 30 TO 40 MPH ARE EXPECTED WITH
THIS STORM.

BSH