Severe Thunderstorm Warning 572, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
209 PM EDT MON AUG 8 2011

.SYNOPSIS...
A WEAK FRONTAL BOUNDARY ALONG WITH A HOT AND HUMID AIRMASS WILL
LINGER ATOP THE REGION INTO TUESDAY. DRIER HIGH PRESSURE WILL BUILD
OVER THE AREA ON WEDNESDAY. MOISTURE AHEAD OF THE NEXT COLD FRONT
WILL RETURN BY SATURDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 2 PM...AT MANY LOCATIONS THE TEMP TREND LAGS THE FCST...WHICH
SUGGESTS THAT OUR HIGH TEMP FCST MIGHT BE A BIT TOO WARM. UNLESS THE
TREND REVERSES...IT APPEARS AS THOUGH WE WILL NOT REACH HEAT
ADVISORY CRITERIA...EVEN THOUGH IT WILL BE PLENTY HOT. CONVECTION
HAS DEVELOPED VIGOROUSLY OVER ERN TN AND WILL MOVE INTO THE WRN
MOUNTAINS SHORTLY AFTER 18Z. NEAR TERM POP TREND WILL BE ADJUSTED
UPWARD ON THE TN BORDER...BUT CONFIDENCE NOT GREAT THAT IT WILL MAKE
IT E OF THE BLUE RIDGE. MODELS SUGGEST A BETTER CHANCE ACROSS THE
UPSTATE SO THE CHANCES WILL BE INCREASED THERE. EXPECT MORE
ADJUSTMENTS LATER THIS AFTERNOON.

REMAINDER OF PREVIOUS DISCUSSION...
THE MOST INTERESTING PART OF THE SHORT TERM FORECAST IS THE
POSSIBILITY OF AN MCS AFFECTING THE FA TONIGHT. THE 0300 UTC RUN OF
OUR LOCAL WORKSTATION WRF IS IN VERY GOOD AGREEMENT WITH THE 0000
UTC GFS IN DEVELOPING AN MCS OVER MO THIS AFTN WHICH THEN TRACKS
QUICKLY EASTWARD THIS EVENING...AFFECTING THE NC MTNS AROUND
MIDNIGHT TONIGHT. THE NAM HAS AN MCS IN A SIMILAR LOCATION LATE IN
THE AFTN...BUT IT DISSIPATES WITH CONVECTION REGENERATING FARTHER TO
THE SOUTHWEST MUCH LATER TONIGHT. SPC FAVORED SUPERCELLS AND
MULTICELL CLUSTERS CONSOLIDATING IN THAT AREA THIS AFTN AND MOVING
ACROSS THE TN VALLEY TONIGHT...MORE LIKE THE GFS AND OUR LOCAL
MODEL. THE DEEP LAYER SHEAR IS A LITTLE WEAK...THOUGH BEHIND THE
CONVECTIVE SYSTEM H5 WINDS ARE ON THE ORDER OF 30 TO 35 KTS. WITH
THE LLVL FLOW VEERING AND STRENGTHENING OVER MIDDLE TN BY LATE
EVENING...THE MORE RAPID EASTWARD MCS PROPAGATION MAKES SENSE. IF
ONLY THE NAM WERE ON BOARD I/D GO WITH LIKELY POPS TONIGHT. AS IT
STANDS I/VE RAISED THEM TO 50 PERCENT A LITTLE AFTER MIDNIGHT ACROSS
THE MTNS. CHANCE POPS HAVE BEEN RUN ACROSS THE REST OF THE FA DURING
THE EARLY MORNING HOURS AS WELL.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
AS OF 140 AM MONDAY...IT REMAINS TO BE SEEN WHAT EFFECTS ANY
MCV OR REMNANTS THEREOF EFFECT DEEP CONVECTIVE DEVELOP EARLY
TUESDAY...BUT ON THE SYNOPTIC SCALE...S/WV ENERGY AND LOW AMPLITUDE
TROUGH REMAINS PROGGED TO SLIDE EAST ACRS THE CWFA. WITHIN THE
LINGERING MOIST AIRMASS...PWATS PROGGED TO BE ABT 125 PERCENT OF
NORMAL...AND WILL PLAN ON RAMPING UP TO MID-CHANCE POP CWFAWIDE AS
BOTH THE NAM AND GFS THUNDER PROBABILITIES ARE EQUIVALENT TO THIS
DESPITE THE EXPECTED DOWNSLOPE FLOW. WITH 85H TEMPS PROGGED TO REMAIN
ABV 20 DEG C AND AIDED BY THE AFOREMENTIONED DOWNSLOPE...EXPECTING
FTHL/PIEDMONT MAXES IN THE MID TO UPPER 90S. WESTERLY LLVL FLOW
SHOULD ALSO AID IN BLYR DRYING AND LOWERING OF SFC DWPTS...SO
APPARENT TEMPS SHOULD BE SIMILAR TO ACTUAL TEMPS.

SUBTLE TROFINESS TRANSLATES DOWNSTREAM OF THE CWFA TUESDAY NIGHT
AND A MUCH DRIER CONTINENTAL AIRMASS IS PROGGED TO OVERSPREAD THE
REGION IN IT/S WAKE. BENEATH MODERATE WESTERLY FLOW ALOFT AND
NW OF SFC TROUGHING...DEEP LAYERED DRYING LOOKS TO LINGER THRU
WEDNESDAY. DOWNSLOPE AIDED DRYING/WARMING WILL SUPPORT PIEDMONT
MAX TEMPS IN THE MID 90S...BUT THE DOWNWARD MIXING OF NOTABLY
LOW DWPTS IS EXPECTED TO CAP ANY DEEP CONVECTIVE CHANCES.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
AS OF 330 AM MONDAY...THERE LOOKS TO BE LITTLE EVIDENCE AFTER
REVIEWING THE RECENTLY POSTED 00 UTC OP GFS AND ECMWF FOR ANY
CHANGES TO FCST FOR THURSDAY AND FRIDAY. EASTERN CONUS L/WV TROUGH
REMAINS PROGGED TO DEAMPLIFY FRIDAY AND LLVL RIDGING COULD GIVE
WAY TO SOME DEGREE OF RETURN FLOW MOISTURE BUT HESITANT AT THIS
POINT TO BUMP UP POP GIVEN THE STILL DRY ECMWF SOLUTION. MAX TEMPS
REMAIN ON TRACK TO FALL WITHIN A FEW DEG F OF THE MID-AUGUST CLIMO.

INCREASED DEEP CONVECTIVE CHANCES WILL REMAIN SLATED FOR
SATURDAY...AS AGAIN...OP MEDIUM RANGE MODEL SOLUTIONS ARE SIMILARLY
DEVELOPING BROAD UPPER DIFFLUENCE DOWNSTREAM OF GREAT LAKES S/WV.
UPPER TROUGH REASSERTS ITSELF ACRS THE EASTERN CONUS ON SUNDAY AS
ATTENDANT COLD FRONT SAGS SOUTH INTO THE REGION.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
AT KCLT...VFR CONDITIONS THROUGH THE PERIOD. FOR THIS AFTERNOON AND
EVENING...MAINLY A WIND FCST. TCLT RADAR WIND PROFILE SHOWS NW IN
THE BOUNDARY LAYER SO EXPECT NW WINDS TO CONTINUE AT THE SFC FOR AT
LEAST THE REMAINDER OF THE DAYLIGHT HOURS. FOR CLOUDS...ONLY A FEW
HIGH-BASED STRATOCU TO DEAL WITH...ALTHO THERE IS A VERY REMOTE
POSSIBILITY OF A SHOWER LATE THIS AFTERNOON. AM WATCHING CONVECTION
MOVING ACROSS ERN TN WITH SOME INTEREST. WESTERLY WIND ALOFT IS LESS
FAVORABLE FOR IT REACHING THE PIEDMONT. THERE IS A LOW CHANCE OF ANY
RESTRICTIONS IN THE MORNING. SOME CONVECTIVE DEBRIS CLOUDS SHOULD
ROLL IN AFTER SUNRISE TUESDAY. THINK ANY DEEPER CONVECTION WILL
PROBABLY HOLD OFF UNTIL AFTER THE END OF THE TAF PERIOD.

ELSEWHERE...GENERALLY A WESTERLY COMPONENT TO THE WIND THIS
AFTERNOON...FUNNELLED BY THE TERRAIN. CONVECTION OVER ERN TN WILL BE
WATCHED FOR IMPACT AT KAVL AND OTHER TAF SITES AND WILL AMEND
ACCORDINGLY. THE BEST CHANCE MIGHT BE AROUND KGSP AROUND 21Z AS
CONVERGENCE IN WNW FLOW MAY AID THE REDEVELOPMENT OF THE
CONVECTION...AS SHOWN BY THE NAM AND WRF-NMM MODELS. FOR NOW...WILL
LEAVE IT OUT. LATER TONIGHT A MORE ORGANIZED AREA OF SHRA/TSTMS MAY
MOVE INTO THE MTNS. SOME FOG IS POSSIBLE AT KAVL AROUND SUNRISE.
THERE SHOULD BE MORE CONVECTIVE DEBRIS CLOUDS AFTER SUNRISE TUESDAY.

OUTLOOK...MOISTURE WILL GRADUALLY DIMINISH EARLY NEXT WEEK IN
PERSISTENT WESTERLY FLOW. STILL EXPECT ISOLD-SCT SHWRS/TSTMS THRU
THE PERIOD.

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...CSH
NEAR TERM...MCAVOY/PM
SHORT TERM...CSH
LONG TERM...CSH/SBK
AVIATION...MCAVOY/PM

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
554 AM EDT MON AUG 8 2011

GAZ018-026-028-029-NCZ035>037-056-057-068>072-082-502-504-506-508-
510-SCZ004>014-019-091000-
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-GREATER OCONEE-GREATER PICKENS-GREATER GREENVILLE-
SPARTANBURG-CHEROKEE-YORK-ANDERSON-ABBEVILLE-LAURENS-UNION SC-
CHESTER-GREENWOOD-
554 AM EDT MON AUG 8 2011

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

.DAY ONE...TODAY AND TONIGHT.

AS AFTERNOON HEAT INDEX VALUES REACH INTO THE LOWER 100S...
ISOLATED THUNDERSTORMS ARE EXPECTED TO DEVELOP. IT IS NOT OUT OF
THE QUESTION THAT A COUPLE OF THESE STORMS WILL PRODUCE DAMAGING
WIND GUSTS OR HAIL TO THE SIZE OF QUARTERS.

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

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

NONE.

GAZ010-017-NCZ033-048>053-058-059-062>065-501-503-505-507-509-
SCZ001>003-091000-
RABUN-HABERSHAM-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-OCONEE MOUNTAINS-
PICKENS MOUNTAINS-GREENVILLE MOUNTAINS-
554 AM EDT MON AUG 8 2011

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

.DAY ONE...TODAY AND TONIGHT.

ISOLATED THUNDERSTORMS ARE EXPECTED TO DEVELOP TODAY. IT IS NOT OUT OF
THE QUESTION THAT A COUPLE OF THESE STORMS WILL PRODUCE DAMAGING
WIND GUSTS OR HAIL TO THE SIZE OF QUARTERS.

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

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

NONE.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
915 AM EDT MON AUG 08 2011

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

0708 PM     TSTM WND DMG     1 E BOILING SPRINGS SC  35.04N 81.96W
08/07/2011                   SPARTANBURG        SC   911 CALL CENTER

            POWERLINES DOWN OFF OF KNOLLWOOD COURT. TIME ESTIMATED
            FROM RADAR.

&&

ZHARGROV

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1038 AM EDT MON AUG 08 2011

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

0728 PM     HAIL             2 NE SPARTANBURG        34.97N 81.90W
08/07/2011  E1.75 INCH       SPARTANBURG        SC   POST OFFICE

            CUSTOMER AT DRAYTON POST OFFICE REPORTED GOLF BALL SIZE
            HAIL THAT DAMAGED HER YARD. TIME ESTIMATED FROM RADAR.

&&

ZHARGROV

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
208 PM EDT MON AUG 8 2011

NCZ051-058-081845-
GRAHAM-SWAIN-
208 PM EDT MON AUG 8 2011

...STRONG THUNDERSTORMS WILL AFFECT GRAHAM AND WESTERN SWAIN COUNTIES
THROUGH 245 PM EDT...

AT 204 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM TALASSEE TO 6 MILES
SOUTHEAST OF CITICO TO 6 MILES WEST OF MURPHY...MOVING EAST AT 25
MPH.

THESE STORMS WILL BE NEAR...
  TAPOCO...
  SANTEETLAH LAKE...
  FONTANA VILLAGE...
  ROBBINSVILLE...
  FONTANA LAKE...

PEOPLE IN GRAHAM AND WESTERN SWAIN COUNTIES...INCLUDING THE FOLLOWING
LOCATIONS...

TAPOCO...SANTEETLAH LAKE...FONTANA VILLAGE...ROBBINSVILLE...FONTANA
LAKE AND STECOAH...

SHOULD MONITOR THE WEATHER SITUATION CLOSELY. LISTEN FOR POSSIBLE
WARNINGS AND BE PREPARED TO TAKE APPROPRIATE ACTION SHOULD SEVERE
WEATHER THREATEN.

MOTHBALL SIZE HAIL...AND WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH
THESE STORMS.

FREQUENT LIGHTNING IS OCCURRING WITH THIS STORM. IF OUTDOORS...STAY
AWAY FROM ISOLATED HIGH OBJECTS SUCH AS TREES. MOVE INDOORS IF
POSSIBLE. WHEN INDOORS...STAY AWAY FROM WINDOWS AND DOORS AND AVOID
USING TELEPHONES UNLESS IT IS AN EMERGENCY. TRY TO UNPLUG UNNECESSARY
ELECTRICAL APPLIANCES BEFORE THE THUNDERSTORM APPROACHES.

LAT...LON 3537 8401 3541 8403 3548 8392 3553 8388
      3553 8383 3557 8377 3558 8360 3557 8353
      3526 8369 3524 8373 3525 8384 3521 8396
      3523 8401 3531 8404 3536 8404

NED