Severe Thunderstorm Warning 353, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
252 PM EDT SUN JUL 27 2008

.SYNOPSIS...
A WEAK COLD FRONT IS EXPECTED TO DISSIPATE AS IT APPROACHES OUR AREA
FROM THE NORTHWEST ON MONDAY. ANOTHER WEAK COLD FRONT WILL MOVE
SLOWLY SOUTHEAST OVER THE CAROLINAS DURING MID WEEK AND STALL OUT
SOUTH OF THE FORECAST AREA LATER IN THE WEEK. ANOTHER UPPER LEVEL
TROUGH WILL THEN PUSH ITS WAY SOUTH AND TOWARD THE CAROLINAS NEXT
WEEKEND.

&&

.NEAR TERM /THROUGH MONDAY NIGHT/...
THE BEST COVERAGE OF SHOWERS AND THUNDERSTORMS ACROSS THE REGION
THIS AFTERNOON/EVENING SHOULD BE WITHIN THE BETTER INSTABILITY
ACROSS THE CENTRAL/EASTERN CAROLINAS. HOWEVER...BOUNDARY LAYER
CONVERGENCE AND MODERATE INSTABILITY WILL YIELD ISOLATED TO WIDELY
SCATTERED THUNDERSTORMS ACROSS THE GSP CWFA AS WELL. IN FACT...WE/VE
SEEN A COUPLE OF CELLS DEVELOP WITHIN THE PAST FEW MINUTES ALONG THE
BLUE RIDGE IN NORTH CAROLINA. A COUPLE OF SEVERE STORMS CANNOT BE
RULED OUT...BUT WITH FREEZING LEVELS AROUND 15 KFT...A HIGH
REFLECTIVITY CORE WILL HAVE TO EXTEND TO AROUND 35 KFT FOR LARGE
HAIL TO OCCUR. ALSO...THE AIR IN THE SUB-CLOUD LAYER IS NOT
ESPECIALLY DRY (DEWPOINT DEPRESSIONS OF 15-20 DEGREES)...WHILE WIND
SHEAR IS MODERATELY STRONG...SO IT APPEARS DAMAGING WIND WILL ONLY
BE A CONCERN IF CONVECTION ORGANIZES ALONG OUTFLOW BOUNDARIES...
WHICH DOESN/T SEEM VERY LIKELY. WHATEVER CONVECTION DOES GET GOING
SHOULD PUSH EAST OF THE CWFA BY MID-EVENING.

DRIER AIR WILL EXIST ACROSS THE AREA ON MONDAY IN THE WAKE OF THE
WEAK COLD FRONT. IN FACT...THE MODELS ARE GENERATING LITTLE IN THE
WAY OF INSTABILITY EXCEPT ACROSS THE EXTREME SOUTHERN FRINGE OF THE
FORECAST AREA...WHILE THE NAM DESTABILIZES THE ATM OVER THE
SOUTHWEST MTNS DURING THE AFTERNOON. WE HAVE ALTERED TOMORROW
AFTERNOON/S SLIGHT CHANCES TO REFLECT THIS DISTRIBUTION OF
INSTABILITY.

&&

.SHORT TERM /TUESDAY THROUGH WEDNESDAY/...
AS OF 245 PM SUNDAY... SLIGHT CHANCE POPS SOUTHERN AND WESTERN ZONES
WILL BE CARRIED INTO MONDAY EVENING WITH GRADUAL DECREASE TO NO POPS
WITH LOSS OF DIURNAL HEATING. SURFACE PATTERN ON TUESDAY WILL BE
DOMINATED BY BERMUDA HIGH CENTERED WELL OFFSHORE WITH AXIS OF HIGH
WESTWARD INTO GULF OF MEXICO. RESULT WILL BE A SOUTHWEST WIND FLOW
ACROSS MOST OF SOUTHEASTERN STATES. WILL INCREASE POPS INTO LOW
CHANCE CATEGORY AS A NOD TOWARD NAM WHICH INCREASES MEAN R.H. IN
WEAKLY CONFLUENT SURFACE WIND FLOW. BOTH GFS AND SREF SHOW WEAK LEE
TROUGH ACROSS PIEDMONT BY LATE IN DAY WEDNESDAY... BUT WILL CARRY
HIGHEST AFTERNOON POPS OVER MOUNTAINS WHERE HEATING IS MOST LIKELY
TO TRIGGER CONVECTION. GUIDANCE INDICATES BASIC SURFACE FEATURES ON
WEDNESDAY WILL ONCE AGAIN CONSIST OF BERMUDA HIGH EXTENDING INTO
SOUTHEASTERN STATES WITH LEE TROUGH ACROSS PIEDMONT. FLOW ALOFT
REMAINS RATHER WEAK FROM THE NORTHWEST... BUT GFS DEPICTS 500 MB
SHORT WAVE APPROACHING FROM THE NORTHWEST. SHORT WAVE WILL PROBABLY
BE A LITTLE TOO FAR AWAY AT END OF DAY TO HAVE MUCH AFFECT ON CWA...
SO WILL GO WITH CHANCE POPS THAT ARE DRIVEN BASICALLY BY DIURNAL
HEATING. TEMPERATURES FORECASTS FOLLOW THE GFS MOS GUIDANCE WHICH
HAS DAYTIME HIGHS IN LOW AND MID 90S EXCEPT 80S IN MOUNTAINS.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 2 PM SUNDAY...BROAD AND WEAK UPPER LEVEL TROF IS EXPECTED TO
CONTINUE ITS SLOW TREK ACROSS THE NORTHEASTERN STATES THROUGH THE
EXTENDED PERIOD. ONCE THIS TROF FINALLY MOVES OFF THE EASTERN
SEABOARD...A SUBSTANTIAL RIDGE WILL BUILD ACROSS THE UPPER PLAINS
AND MOVE SLOWLY EASTWARD. THURSDAY STILL APPEARS TO BE THE MOST
ACTIVE DURING THE PERIOD WITH A STRONG SHORT WAVE TRAVERSING THE
AREA. INSTABILITY SHOULD REMAIN FAIRLY HIGH FOR MOST OF THE PERIOD
AND PROVIDE FOR AT LEAST A SLIGHT CHANCE OF THUNDERSTORMS THROUGH
THE WEEKEND. THE MID AND UPPER LEVELS DO DRY OUT FRI AND SAT AS A
SUBSIDENCE PATTERN SETS UP AND DYNAMIC FORCING LOOKS POOR. TEMPS ARE
STILL EXPECTED TO BE A FEW DEGREES ABOVE NORMAL DUE IN PART TO THE
UNCHANGING AIRMASS. AMPLE BOUNDARY LAYER MOISTURE SHOULD ALSO HELP
KEEP MIN TEMPS A COUPLE DEGREES ABOVE NORMAL AS WELL.

&&

.AVIATION /19Z SUNDAY THROUGH FRIDAY/...
THE ATMOSPHERE HAS BECOME MODERATELY UNSTABLE THIS AFTERNOON...AND
VISIBLE SATELLITE INDICATES QUITE A BIT OF TOWERING CU
DEVELOPING...ESPECIALLY ALONG THE BLUE RIDGE...AND ALONG/EAST OF THE
I-77 CORRIDOR. AS SUCH...IT APPEARS THAT KHKY AND KCLT STAND THE
BEST CHANCE OF EXPERIENCING A TSRA THIS AFTERNOON...SO VCTS WILL BE
CARRIED THERE. ELSEWHERE...CONVECTION SHOULD BE MORE ISOLATED...SO A
CB CLOUD GROUP APPEARS TO BE MORE APPROPRIATE AT THOSE TERMINALS.
CONVECTION SHOULD CLEAR THE AREA BY EARLY EVENING...LEAVING MOSTLY
CLEAR SKIES THROUGH 18Z MONDAY. SOME EARLY MORNING MVFR WILL BE
POSSIBLE AT KAVL.

OUTLOOK...THE AXIS OF A LONG WAVE TROF WILL REMAIN NEAR THE ATLANTIC
COAST THROUGH TUESDAY. WEAK DISTURBANCES WITHIN THE TROF MAY TRIGGER
AFTERNOON AND EVENING THUNDERSTORMS. A BACK DOOR COLD FRONT WILL
SLIDE TOWARDS THE FORECAST AREA WEDNESDAY AND THURSDAY. COVERAGE OF
SHOWERS AND THUNDERSTORMS SHOULD INCREASE EACH DAY. RICH LLVL
MOISTURE MAY RESULT IN PATCHY FOG EACH MORNING.

&&

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

&&

SYNOPSIS...JPT
NEAR TERM...JDL
SHORT TERM...LGL
LONG TERM...JPT
AVIATION...JDL

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
556 AM EDT SUN JUL 27 2008

GAZ010-017-018-026-028-029-NCZ033-035>037-048>053-056>059-062>065-
068>072-082-501>510-SCZ001>014-019-281000-
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-
556 AM EDT SUN JUL 27 2008

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

.DAY ONE...TODAY AND TONIGHT.

SHOWERS AND THUNDERSTORMS WILL DEVELOP THIS AFTERNOON...MAINLY
EAST OF INTERSTATE 85. ONE OR TWO OF THESE THUNDERSTORMS COULD
REACH SEVERE LEVELS AND PRODUCE DAMAGING WIND...LARGE HAIL AND
HEAVY RAINFALL.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY.

SCATTERED THUNDERSTORMS WILL DEVELOP EACH AFTERNOON AND EVENING MONDAY
THROUGH FRIDAY. IN ADDITION TO LOCALLY HEAVY RAINFALL AND CLOUD TO
GROUND LIGHTNING STRIKES...A FEW THUNDERSTORMS COULD BECOME
SEVERE...PRODUCING HAIL AS LARGE AS PENNIES AND DAMAGING WIND
GUSTS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.

KRENTZ

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
249 PM EDT SUN JUL 27 2008

NCZ037-271915-
DAVIE-
249 PM EDT SUN JUL 27 2008

...A STRONG THUNDERSTORM WILL AFFECT DAVIE COUNTY THROUGH 315 PM
EDT...

AT 249 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM NEAR FARMINGTON...OR 8 MILES NORTH OF
MOCKSVILLE...MOVING SOUTHEAST AT 15 MPH.

THIS STORM WILL BE NEAR...
  BERMUDA RUN BY 300 PM EDT.
  ADVANCE BY 315 PM EDT.

PEA SIZE HAIL...AND WIND GUSTS OF 30 TO 40 MPH ARE EXPECTED WITH THIS
STORM.

INTENSE 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.

BSH