Severe Thunderstorm Warning 86, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1107 AM EDT FRI APR 21 2006

.SHORT TERM /REST OF TODAY/...
LARGE AREA OF CONVECTION ACROSS EAST TENN AND FAR WESTERN NC IS
LIFTING GRADUALLY NORTH. IT APPEARS THAT THE MAIN CULPRIT FOR THIS
ACTIVITY IS FAIRLY STRONG CONVERGENCE AT THE NOSE OF A 30-40 KT
LLJ...AND AN AREA OF UPPER DIVERGENCE SOUTH OF THE UPPER JET AXIS
ACROSS THE UPPER MIDWEST. THE MODELS APPEAR TO BE IN GOOD AGREEMENT
THAT THIS AREA OF DEEPER FORCING WILL LIFT NORTH TOWARD THE CENTRAL
APPALACHIANS AND OHIO VALLEY LATER TODAY. THEREFORE...EXPECT A LULL
IN WIDESPREAD CONVECTION DURING THE MID-AFTERNOON...ALTHOUGH WITH A
VERY MOIST AIRMASS (PWATS AROUND 175 PERCENT OF NORMAL) AND WEAK
IMPULSES MOVING THROUGH SOUTHWEST FLOW ALOFT...CERTAINLY CAN/T RULE
OUT THE POSSIBILITY OF SCATTERED OR EVEN NUMEROUS SHOWERS AND STORMS
AS WE DESTABILIZE THIS AFTERNOON. MEANWHILE...EXPECT MORE ORGANIZED
ACTIVITY TO HOLD OFF UNTIL THIS EVENING...AS SURFACE BOUNDARY
APPROACHES FROM THE GREAT VALLEY...AND CONVERGENCE MAXIMIZES ALONG A
NORTHWEST-TO-SOUTHEAST ORIENTED SURFACE TROUGH ACROSS CENTRAL GA.
WITH THE LACK OF ANY KIND OF SIGNIFICANT FOCUS FOR CONVECTION THIS
AFTERNOON...WILL LOWER POPS ABOUT 20 PERCENT ACROSS THE BOARD FOR
THIS AFTERNOON. OTHERWISE...THE FORECAST APPEARS TO BE IN REASONABLY
GOOD SHAPE...AND PLAN ONLY MINOR TWEAKS TO ALL OTHER FORECAST
PARAMETERS THIS AFTERNOON.

&&

.PREV DISCUSSION...
 /ISSUED 240 AM EDT FRI APR 21 2006/

SHORT TERM /TODAY THROUGH SATURDAY NIGHT/...
UPPER LOW MOVG OVER GREAT LAKES WILL KEEP THE WAVE TRAIN GOING
ACROSS THE AREA WITH CONTINUED MOIST SW FLOW. TIMING OF THESE
INDIVIDUAL SHORTWAVES HAS NOT BEEN HANDLED WELL BY THE MODELS
RECENTLY. THERE ARE ALSO TIMING/ORIENTATION DIFFERENCES BETWEEN
THE NAM AND GFS. IN ANY CASE...GULF MOISTURE IS FLOWING INTO THE
REGION AND THE CHANCE OF RAIN IS MUCH IMPROVED COMPARED TO RECENT
WEEKS...TODAY WILL BE NO EXCEPTION. THETA-E RIDGE INCREASES OVER
MTNS EARLY AND WILL CONTINUE WITH CAT POPS THERE THROUGH MID
DAY...WITH AT LEAST LIKELY SHWRS/TSTMS ACROSS CWA THIS AFTN THRU
TONIGHT. BOTH NAM AND GFS SHOW UPPER TROF AXIS ROTATING THROUGH
AREA EARLY SAT AND THIS WILL LIKELY BRING A GOOD ROUND OF
CONVECTION LATE FRI NIGHT THROUGH SAT MORNING. LATEST MODEL RUNS
SLOWER MOVG UPPER LOW E AND CONVECTION COULD CONTINUE THRU THE DAY
AND INTO THE EVE. LOOKING FOR ABV AVG TEMPS TODAY...NEAR AVG SAT.

LONG TERM /SUNDAY THROUGH THURSDAY/...
UPPER TROF CONTINUES E ACROSS GREAT LAKES SUN WHILE SURFACE HIGH
BUILDS INTO AREE FROM THE W. EXPECT A DRYING AND WARMING TREND SUN
AND MON...WITH A CHANCE OF SHOWERS RETURNING LATE TUE AND WED. COOL
HIGH PRESSURE BUILDS IN FROM THE N ON THU. NO SIG CHANGES MADE TO
GRIDDED FORECAST AFTER SAT NIGHT.

AVIATION...
LEFTOVER SHRA AND OUTFLOW WILL CONTINUE TO DISSIPATE OVER THE
UPSTATE EARLY THIS MORNING. CONDITIONS SHOULD PRIMARILY REMAIN VFR
WITH THE EXCEPTION OF SOME TEMPORARY MVFR FOG POSSIBLE AROUND
SUNRISE...ESPECIALLY KAND AND KAVL. SHORT RANGE MODELS INDICATE THAT
THE NEXT ROUND OF CONVECTION OVER CENTRAL TN AND KY SHOULD BEGIN TO
MOVE EAST BETWEEN 15-18Z. THE STEERING FLOW SHOULD RESULT IN STORM
MOTIONS FROM SW TO NE...RESULTING IN SLOW PROGRESS EAST. BEST CHC
APPEARS TO OCCUR LATE THIS AFTERNOON...HOWEVER...CHCS ARE TOO SMALL
TO MENTION IN THE TAFS. THE NEXT CHC MAY OCCUR LATE FRI NIGHT AS
SHARP MID TROF MOVES OVER THE SOUTHERN APPALACHIANS.

&&

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

SHORT TERM...LANE

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
331 AM EDT FRI APR 21 2006

GAZ010-017-018-026-028-029-NCZ033>037-048>059-062>072-082-
SCZ001>014-019-220745-
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 NC-
OCONEE MOUNTAINS-PICKENS MOUNTAINS-GREENVILLE MOUNTAINS-
GREATER OCONEE-GREATER PICKENS-GREATER GREENVILLE-SPARTANBURG-
CHEROKEE-YORK-ANDERSON-ABBEVILLE-LAURENS-UNION SC-CHESTER-
GREENWOOD-
331 AM EDT FRI APR 21 2006

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

.DAY ONE...TODAY AND TONIGHT

LOOK FOR THUNDERSTORMS IN THE AREA TODAY AND TONIGHT. SOME STORMS
COULD BECOME SEVERE...THE MAIN THREAT BEING LARGE HAIL AND WIND.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

THUNDERSTORMS ARE EXPECTED TO CONTINUE ACROSS THE AREA SATURDAY INTO
SATURDAY EVENING. THERE IS ANOTHER CHANCE OF THUNDERSTORMS
WEDNESDAY AND WEDNESDAY NIGHT. SOME STORMS COULD BE SEVERE.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED LATER TODAY.