Severe Thunderstorm Warning 68, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
911 PM EDT THU MAY 19 2005

.SHORT TERM (REST OF TONIGHT)...
CWFA CURRENTLY IN A CONVECTIVE LULL...ONLY SCT CONVECTION OVER NC
MTNS WITH ISOLATED ELSEWHERE. HAVE BACKED OFF ON EVENING POP TO
COVER CURRENT TREND. EXPECT CONVECTION TO PICK UP LATER AS SHORT
WAVE MOVES INTO THE AREA. 00Z RAOBS SHOW ATMOS BECOMING
CONDITIONALLY UNSTABLE WITH THE LOSS OF HEATING. THE SHORT WAVE
SHOULD PROVIDE ENOUGH LIFT FOR PARCELS TO REACH LFC. POP BECOMING
CATEGORICAL BY MORNING AS MCS...OR ITS REMNANTS MOVE INTO THE AREA.
RAOBS SHOW GOOD DIRECTIONAL SHEAR...BUT LOW SPEED SHEAR. AS THE WAVE
MOVES CLOSER...WINDS BECOME MORE UNIDIRECTIONAL BUT SPEEDS INCREASE
SIGNIFICANTLY. ISOLATED SVR TSRA STILL POSSIBLE THIS EVENING...BUT
CHANCES DIMINISHING WITH HEATING. MCS...OR REMNANTS...COULD PRODUCE
ISOLATED SVR TSRA OVER NC MTNS LATE TONIGHT...BUT CHANCE WILL BE
BETTER TO OUR WEST.

MADE SOME MINOR ADJUSTMENTS TO TEMP...DEW POINTS AND WINDS AS WELL.
&&

.PREVIOUS DISCUSSION...
(ISSUED 257 PM EDT THU MAY 19 2005)

SHORT TERM (TONIGHT THROUGH SUNDAY)...
SCT STRONG TSTMS HAVE DEVELOPED ALONG THE LEE SLOPES THIS AFTN. THIS
WAS EXPECTED...BUT THE STRENGTH OF SOME OF THE STORMS IS A LITTLE
SURPRISING. MID 60 DWPTS AND A LIGHT UPSLOPE FLOW HAVE RESULTED IN
SB-CAPE VALUES OF BETWEEN 2000-2500 IN MANY AREAS. STORMS WILL
LIKELY CONTINUE THROUGH SUNSET AS THEY DRIFT SOUTHEAST INTO THE AXIS
OF THE WARM...MOIST AIR IN THE LEE. SHEAR WL REMAIN QUITE WEAK AND
DO NOT EXPECT CONVECTION TO ACHIEVE AND DEGREE OF ORGANIZATION.

SYNOPTIC SCALE FORCING...IN THE FORM OF PRONOUNCED UPPER
DIVERGENCE...WL INCREASE AFTER MIDNIGHT AS UPPER LOW CURRENTLY OVER
SRN WI DROPS SE UNDER AN MUCH LARGER UPPER LOW OVER NEW ENGLAND. GFS
HAS COME AROUND TO A MORE NAM-LIKE SOLUTION AS BOTH MODELS OPEN THE
CLOSED LOW AND BRING IT THROUGH THE WRN CAROLINAS AS AN ADVECTIVE
SHORT WAVE FRI.

AS DIFFLUENCE INCREASES...EXPECT CONVECTION TO BECOME MORE
WIDESPREAD AFTER MIDNIGHT. MOS REFLECTS THIS WITH CAT POPS AND HAVE
FOLLOWED SUIT ACROSS THE ENTIRE CWFA. INSTABILITY IS QUITE LIMITED
BY LATE TNGT...SO THINK THAT SEVERE THREAT WL BE LIMITED.

WIDESPREAD PCPN WL CONTINUE FRI MORNING. BY FAR THE BEST DEEP LAYER
SHEAR AND INSTABILITY WL MISS US WELL TO THE WEST AS MID LEVEL WINDS
WL BE MUCH STRONGER ON THE WESTERN SIDE OF THE TROF AND LAPSE RATES
WL BE STEEPER THERE. HOWEVER...DESPITE THE WEAK SHEAR AND MORE
LIMITED INSTABILITY OVER THE WRN CAROLINAS AND NE GA...THE
COMBINATION OF GOOD LLVL CONVERGENCE WITH THE SFC TRIPLE POINT
WORKING THROUGH THE REGION...AND COOL TEMPERATURES ALOFT UNDER THE
TROF...SHOULD BE GOOD FOR A RASH OF CONVECTION IN THE AFTN. SOME
OF THESE WL PROBABLY PRODUCE SEVERE CRITERIA HAIL.

CONVECTION MAY CONTINUE WELL INTO THE EVENING FRI AS SFC CONVERGENCE
WL INCREASE BEHIND THE LOW AS A BACK DOOR FRONT DROPS ACROSS THE
CWFA. MODELS PROJECT GOOD MOISTURE POOLING ALONG THE BNDRY. ANY
PCPN SHOULD COME TO AN END EARLY SATURDAY WITH RAPID CLEARING AND
A BRISK NE WIND. CONTINUED MILD AND DRY ON SUNDAY.

LONG TERM (SUNDAY NIGHT THROUGH THURSDAY)...
MEDIUM RANGE MODELS HAVE TRENDED MORE TOWARD THE LAST FEW UKMET
AND/OR ECMWF RUNS WITH DEEPER DEVELOPMENT OF MEAN EASTERN U.S.
TROUGHING. OVERALL THIS LEAD TO A LOWERING OF DAILY MAXES FOR
DAYS 4-7...AS CWFA SHOULD BE CAUGHT WITHIN CYCLONIC CIRCULATION
AT LEAST INTO DAY 6...WITH TIMING OF ANY DEAMPLIFYING FLOW STILL
UNCERTAIN TOWARD THE END OF THE PERIOD. WILL PLAN ON ROUGH TIMING
OF IMPULSE AND ATTENDANT COLD FRONT SWINGING THRU ON MONDAY...WITH
JUST SMALL OR SLIGHT CHANCES OF DEEP CONVECTION AT THAT TIME.

AVIATION...
AN EARLY START TO DEEP CONVECTIVE INITIATION ALONG THE BLUE RIDGE
INDICATIVE OF OVERALL HIGHER RH & K INDEX VALUES ACRS THE CWFA.
WEAKLY SHEARED ENVIRONMENT CONTRIBUTES TO DIFFICULTLY IN TIMING
TSRA CHANCES INTO ANY ONE TERMINAL...BUT BASED ON EXPECTED EVENTUAL
CVRG...FEEL THAT THERE IS 50/50 CHANCE FOR GREATER FOR TSRA TO OCCUR
AT ANY ONE SITE AT SOME POINT THROUGH 00Z...SO CONTINUED TEMPOS AT
ALL SITES THIS AFTERNOON/EARLY EVENING. PROBABLY WILL WIND UP WITH
JUST A MIX OF DEBRIS CLDS AS THE EVENING WEARS ON AFTER DEEP
CONVECTION DISSIPATES WITH LOSS OF HTG. GENERAL AGREEMENT AMONG
MODELS/NUMERICAL GUIDANCE IN REDEVELOPING AT LEAST MVFR LVL STRATCU
AFTER MIDNIGHT WITHIN LLVL WAA IN ADVANCE OF NEXT SLUG OF DEEP
FORCING AND RH...GENERALLY CENTERED AROUND DAYBREAK FRIDAY.

&&

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

SHORT TERM...RWH

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
352 AM EDT THU MAY 19 2005

GAZ010-017-018-026-028-029-NCZ033>037-048>059-062>072-082-
SCZ001>014-019-200800-
RABUN-HABERSHAM-STEPHENS-FRANKLIN-HART-ELBERT-AVERY-CALDWELL-
ALEXANDER-IREDELL-DAVIE-MADISON-YANCEY-MITCHELL-SWAIN-HAYWOOD-
BUNCOMBE-MCDOWELL-BURKE-CATAWBA-ROWAN-GRAHAM-NORTHERN JACKSON-
MACON-SOUTHERN JACKSON-TRANSYLVANIA-HENDERSON-POLK-RUTHERFORD-
CLEVELAND-LINCOLN-GASTON-MECKLENBURG-CABARRUS-UNION-
OCONEE MOUNTAINS-PICKENS MOUNTAINS-GREENVILLE MOUNTAINS-
GREATER OCONEE-GREATER PICKENS-GREATER GREENVILLE-SPARTANBURG-
CHEROKEE-YORK-ANDERSON-ABBEVILLE-LAURENS-CHESTER-GREENWOOD-
352 AM EDT THU MAY 19 2005

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

.DAY ONE...TODAY AND TONIGHT

THERE IS AN INCREASING CHANCE OF THUNDERSTORMS TODAY...BECOMING
LIKELY TO CATEGORICAL OVERNIGHT. SOME STORMS ARE LIKELY TO CONTAIN
AT LEAST SMALL HAIL AND STRONG GUSTY WINDS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

THUNDERSTORMS ARE EXPECTED FRIDAY...WITH A DECREASING CHANCE
FRIDAY NIGHT. THERE IS ANOTHER CHANCE OF THUNDERSTORMS MONDAY AND
MONDAY NIGHT.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED LATE THIS AFTERNOON AND EVENING.

RB

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
942 PM EDT THU MAY 19 2005

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

0915 PM     TSTM WND DMG     CANTON                  35.55N 82.84W
05/19/2005                   HAYWOOD            NC   COUNTY OFFICIAL

            PORTIONS OF A TIN ROOF WAS DAMAGED ON A BARN ON HANNAH
            COVE ROAD.

&&

NED

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1141 PM EDT THU MAY 19 2005

GAZ017-018-026-028-200430-
FRANKLIN GA-HABERSHAM-HART-STEPHENS-
INCLUDING THE CITIES OF...CLARKESVILLE...HARTWELL...TOCCOA
1141 PM EDT THU MAY 19 2005

...STRONG THUNDERSTORMS MOVING INTO NORTHEAST GEORGIA BY MIDNIGHT...

STRONG THUNDERSTORMS HAVE DEVELOPED IN NORTHEAST GEORGIA AND SHOULD
PASS SOUTH OF CORNELIA TO NEAR TOCCOA AND CARNESVILLE.  THE
STRONGEST STORM IS EXPECTED TO MOVE INTO FRANKLIN COUNTY BEFORE
MIDNIGHT.  THESE THUNDERSTORMS WILL PRODUCE STRONG GUSTY WINDS TO 45
MPH...PEA TO DIME SIZE HAIL...AND FREQUENT LIGHTNING STRIKES.
BRIEF HEAVY RAIN WILL CAUSE PONDING OF WATER ON ROADS AND IN LOW
AREAS.

BENTHALL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1242 AM EDT FRI MAY 20 2005

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

1237 AM     HAIL             REED CREEK              34.44N 82.92W
05/20/2005  1.00 INCH        HART               GA   LAW ENFORCEMENT

            HAIL THE SIZE OF QUARTERS 5 MILES NORTH OF HARTWELL IN
            REED CREEK COMMUNITY.

&&

TJB

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1247 AM EDT FRI MAY 20 2005

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

1243 AM     HAIL             8 N SHELBY              35.40N 81.54W
05/20/2005  0.88 INCH        CLEVELAND          NC   UNKNOWN

            PUBLIC REPORT OF NICKEL SIZE HAIL 8 MILES NORTH OF SHELBY
            ON HWY 226.

&&

TJB

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
106 AM EDT FRI MAY 20 2005

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

1200 AM     TSTM WND DMG     AVALON                  34.50N 83.19W
05/20/2005                   STEPHENS           GA   COUNTY OFFICIAL

            TREES DOWN IN AVALON AREA, ONE ON MARTIN DRIVE.

&&

TJB