Severe Thunderstorm Warning 80, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1116 AM EDT SAT JUN 12 2004

.UPDATE...

IMPRESSIVE SATELLITE LOOP ATTM OF THE CAD AIRMASS PUSHING
SOUTHWARD...CURRENTLY AS FAR SOUTH AS THE NRN NC PIEDMONT. AHEAD OF
THE FRONT SH/ISO TS HAVE DEVELOPED OVER THE TN/NC LINE. ENVIRONMENT
OVER THE WESTERN CAROLINAS AND NE GA IS DESTABILIZING RAPIDLY AS
TEMPS ARE ALREADY IN THE UPPER 80S TO LOWER 90S OVER MID 60 DWPTS.
CAPES ARE EXPECTED TO REACH THE 2500-3500 J/KG WINDOW THIS AFTERNOON
AHEAD OF THE WEDGE. BY 18Z...I WOULD EXPECT A LINE OF CONVECTION TO
DEVELOP FROM KAVL TO KSPA EAST TO UNION...NOT TO MENTION ISO
ACTIVITY SOUTH AND WEST. A FEW SVR TS ARE EXPECTED TO
RESULT...MAINLY A WIND THREAT...CURRENT SPS HIGHLIGHTS NICELY. VIL
EQUATION APPLIED TO THE ETA FORECASTS A HIGH VALUE OF 60-65 VIL
NEEDED FOR 3/4 HAIL. WILL TWEAK POPS TO REFLECT CURRENT TIMING.
WITH WEDGE ALREADY OVER THE NE CWA WILL KEEP TEMPS LIMITED TO
CURRENT VALUES. SOUTH OF THE FRONT...TEMPS SHOULD RISE THROUGH
18-19Z BEFORE LEVELING OFF AND BEGINNING TO FALL. WILL ALSO MAKE
SMALL ADJUSTMENTS TO WINDS AND SKY COVERAGE.

&&

.PREV DISCUSSION...
BACKDOOR COLD FRONT SAGGING SOUTH TOWARD THE REGION THIS MORNING.
MESOSCALE ANALYSIS SUGGESTS DRIER AIR SLOWLY APPROACHING THE CWFA
FROM THE NORTH. BOTH ETA AND GFS CONTINUE DROPPING THIS FEATURE
SOUTH...AND IT IS PROGD TO BE ALONG THE SOUTHERN PERIPHERY OF THE
CWFA BY EARLY EVENING. LITTLE IN THE WAY OF UPPER SUPPORT...WITH
CWFA STILL IN CRUX OF RIDGING ALOFT...ALTHOUGH ETA DOES BRING A
VORT AXIS TO THE SPINE OF THE APPALACHIANS THIS EVENING. BIG
QUESTION IS HOW DRY THE ATMOSPHERIC COLUMN WILL BE AT TIME OF
MAXIMUM HEATING FOR CONVECTION IN THE NORTHEAST. FORECAST SOUNDINGS
STILL FAIRLY WET AND UNSTABLE UP THERE THIS AFTERNOON. NEITHER ETA
OR GFS PRODUCES MUCH IN THE WAY OF RAINFALL IN THE NORTHWEST
PIEDMONT THIS AFTERNOON. FOR NOW...WE WILL MENTION LOW CHANCE UP
THERE THIS AFTERNOON...WITH POPS INCREASING TO THE LOWER AND MID
40% RANGE SOUTHERN SECTIONS LATE. SATELLITE IMAGERY SHOWS CLOUDS
INCREASING FROM THE NORTHEAST BEHIND THE FRONT...AND BOTH ETA AND
GFS BRING A MOISTER BOUNDARY LAYER INTO THE CWFA BY MID AFTERNOON.
WILL COOL NORTHERN SECTIONS AS WITH PREVIOUS PACKAGE GIVEN WEAK
COLD ADVECTION BEHIND THE FRONT AND ANTICIPATED CLOUD COVER...BUT
WILL WARM THE SOUTH A TAD PER LATEST MOS. FORECAST SOUNDINGS SUGGEST
EXTREMELY WEAK STORM MOTIONS UPSTATE/NORTHEAST GEORGIA LATE
AFTERNOON...WITH INVERTED-V SOUNDINGS ACROSS THE GEORGIA AND SOUTH
CAROLINA PIEDMONT LATE.

AS FRONT SAGS SOUTH...FLOW ALOFT TURNS ENOUGH TO PRODUCE A PROLONGED
PERIOD OF UPGLIDE OVER THE BOUNDARY. ETA KEEPS A BROAD LOBE OF
DIFFERENTIAL POSITIVE VORTICITY ADVECTION ACROSS THE APPALACHIANS
FOR MUCH OF THE OVERNIGHT. SOUNDINGS COOL SOMEWHAT BUT STILL RATHER
MOIST. DESPITE WEAK INSTABILITY...UPSLOPE SHOWERS SHOULD BE AT LEAST
SCATTERED IN NATURE OVERNIGHT...WITH BEST CHANCES SOUTH AND WEST.
WILL GO DRY BEYOND THIS EVENING EASTERN CORRIDOR.

FRONT STILL SOUTH OF REGION SUNDAY...UPGLIDE CONTINUES AND DRIER
AIR BEGINS ERODING IN NORTHEAST SECTIONS. ETA AND GFS BEGIN TO DIFFER
WITH THEIR HANDLING OF FEATURES ALOFT. STILL...BOTH PRODUCE
SCATTERED CONVECTION SOUTH AND WEST. WE WILL KEEP EXTREME EASTERN
ZONES DRY SUNDAY AFTERNOON WITH POPS INCREASING TOWARD SOUTHERN AND
WESTERN SECTIONS.

BOTH MODELS DEPICT A CLOSED LOW TAKING SHAPE IN THE GULF REGION AS
THE NEW WEEK BEGINS...WITH WESTERLIES DROPPING SOUTH WHICH SHOULD
ALLOW A COLD FRONT TO SAG SOUTH TOWARD OUR REGION MONDAY AND
TUESDAY. ETA SURFACE RIDGING OFF THE ATLANTIC COAST SHIFTS AWAY AND
CWFA SHOULD BE IN RETURN FLOW AT THAT POINT...AND ETA BRINGS A
STRONG VORT OVER THE SOUTHEAST STATES. GFS SEEMS TO WANT TO DEVELOP
A TROPICAL SYSTEM IN THE WEAK UPPER LEVEL ENVIRONMENT AND TAKE IT
INTO THE SOUTHEAST STATES EARLY IN THE WEEK...TO GET ENTRAINED IN
APPROACHING COLD FRONT. WE WENT GOOD CHANCE POPS FOR CENTRAL CWFA AND
SOLID CHANCE ALL OTHER LOCATIONS MONDAY...WITH WARMER TEMPERATURES.

A FEW ADJUSTMENTS WERE MADE TO CLOUD COVER...AND TEMPERATURES MONDAY
NIGHT IN ANTICIPATION OF APPROACHING FRONT. FEW OTHER CHANGES
NECESSARY AT THIS JUNCTURE.
SAB
&&

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

NED

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
557 AM EDT SAT JUN 12 2004

GAZ010-017-018-026-028-029-NCZ033>037-048>059-062>072-082-SCZ001>014-
019-130956-
ABBEVILLE SC-ALEXANDER NC-ANDERSON SC-AVERY NC-BUNCOMBE NC-BURKE NC-
CABARRUS NC-CALDWELL NC-CATAWBA NC-CHEROKEE SC-CHESTER SC-
CLEVELAND NC-DAVIE NC-ELBERT GA-FRANKLIN GA-GASTON NC-GRAHAM NC-
GREATER GREENVILLE SC-GREATER OCONEE SC-GREATER PICKENS SC-
GREENVILLE MOUNTAINS SC-GREENWOOD SC-HABERSHAM GA-HART GA-HAYWOOD NC-
HENDERSON NC-IREDELL NC-LAURENS SC-LINCOLN NC-MACON NC-MADISON NC-
MCDOWELL NC-MECKLENBURG NC-MITCHELL NC-NORTHERN JACKSON NC-
OCONEE MOUNTAINS SC-PICKENS MOUNTAINS SC-POLK NC-RABUN GA-ROWAN NC-
RUTHERFORD NC-SOUTHERN JACKSON NC-SPARTANBURG SC-STEPHENS GA-
SWAIN NC-TRANSYLVANIA NC-UNION SC-UNION NC-YANCEY NC-YORK SC-
557 AM EDT SAT JUN 12 2004

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

.DAY ONE...
A COLD FRONT MOVING INTO THE REGION TODAY WILL BE THE FOCUS FOR
SHOWERS AND THUNDERSTORMS THIS AFTERNOON. A FEW OF THE STORMS COULD
BE QUITE STRONG...ESPECIALLY IN UPSTATE SOUTH CAROLINA AND EXTREME
NORTHEAST GEORGIA...AND AN ISOLATED SEVERE STORM CANNOT BE RULED OUT.
STORMS THIS AFTERNOON SHOULD MOVE SLOWLY...ENHANCING HEAVY RAINFALL
POTENTIAL. SEE THE LATEST SEVERE WEATHER OUTLOOK...UNDER THE PRODUCT
HEADER CAESPSGSP...FOR MORE DETAILS.

.DAYS TWO THROUGH SEVEN...

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE REQUIRED LATER TODAY IN UPSTATE SOUTH
CAROLINA AND EXTREME NORTHEAST GEORGIA.

44