Severe Thunderstorm Warning 25, NWS Greenville-Spartanburg, SC

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
323 PM EDT SUN APR 28 2002

SUPERCELLULAR DEEP CONVECTION ACRS ERN TENN MOVING TOWARD NC MTNS
ATTM IS THE PRIMARY CONCERN THRU EARLY EARLY EVENING...BUT THIS
IS WELL COVERED WITH WW170 THRU 23Z. POTENTIAL FOR ADDITIONAL
DEEP CONVECTION IS A LITTLE LESS CERTAIN...BUT SYNOPTIC SCALE
FEATURES MENTIONED IN PRELIM DISC STILL LOOK FAVORABLE. WILL KEEP
12 HR 7P-7A POP IN SCATTERED/CHC RANGE FROM 50% W TO 30% E.

WINDS STILL QUITE GUSTY ESP...ACRS THE MTNS/FTHLS...SO WILL HAVE
LWA FOR THE EVENING HOURS.

PRELIM DISC:

AXIS OF HIGH THETA-E AIR & LLVL CONVERGENCE AXIS WILL BE SAGGING SE
INTO THE CWFA THRU THIS EVENING. EVEN THOUGH THE GSP CWFA IS WELL
SOUTH OF THE STRONG UPPER FORCING...THESE AFOREMENTIONED
PARAMETERS...COMBINED WITH A STRONG & DEEP LAYERED VERTICAL WIND
PROFILE & BULLSEYE OF UPPER LVL DIVERGENCE IN LEFT EXIT REGION OF
25H JET...ORGANIZED SVR TSTMS STILL A POSSIBILITY...WHETHER THEY ARE
ASSOCIATED WITH ACTIVITY OUT AHEAD OF APPROACHING COLD FRONT OR
ACTIVATED BY LEE TROUGH. AT THE MOMENT...PLAN ON MENTIONING SVR CHCS
THIS EVENING IN ZFP FOR NC MTNS & MAY EXPAND THIS AREA EASTWARD AS
THE AFTERNOON WEARS ON AS WE GET A BETTER HANDLE ON THINGS...OR
WATCHES DICTATE THIS FOR US.

POST FRONTAL AIRMASS & MIXING WORKS IN FROM WEST TO EAST OVERNIGHT
& IT LOOKS LIKE BL FLOW WILL BE STRONG ENUF FOR FCST OF ONGOING
GRADIENT WINDY CONDITIONS ACRS THE MTNS. THE SAME HOLDS TRUE FOR
MONDAY & WILL CONFINE WINDY WORDING TO MTN ZONES. PRES GRADIENT
LOOSENS IN THE AFTERNOON AS HIGH BLDS EAST THEN SETTLES OVER THE
CWFA MONDAY NIGHT PROMOTING CLEAR AND CALM CONDITIONS. RETURN
FLOW DEVELOPS QUICKLY DURING TUESDAY...BUT AT THIS POINT...WILL
LEAN TOWARD LESS AGGRESSIVE ETA SOLUTION...KEEPING MEASURABLE
PCPN WEST/SW OF CWFA UNTIL TUE NITE.

HEIGHTS ACROSS THE ERN US WILL RISE ON DAY 3 IN RESPONSE TO S/WV
ENERGY HEADING INTO THE NATIONS MID SECTION. AT THE SFC...WARM
FRONT WILL LIFT NORTHWARD ACRS THE CWFA WITH WARM SECTOR WX FOR
THURSDAY...ESPECIALLY WHEN FAVORING FURTHER N ECMWF POSITION OF
SURFACE FRONT ON DAY 4. CONVERSELY...AS S/WV TRANSLATES ACRS THE
EASTERN U.S. ON DAY 5...DRAGGING A COLD FRONT ACRS THE CWFA...TIMING
OF THIS LOOKS TO BE LATER THAN GFS ENSEMBLES...BUT WILL NOT EXTEND
POPS PAST FRIDAY. WITH UPPER RIDGING BUILDING OFF TO OUR WEST THIS
WEEKEND...A PREDOMINATELY DRY NW FLOW WILL RESULT ACRS THE EASTERN
US. MODELS INDICATING SOME ATLANTIC RH RETURNING ON EASTERLY LLVL
FLOW...BUT WILL CONTINUE TO KEEP DAY 6-7 DRY.

FCSTID = 55
GSP   58  79  51  80 /  20   0   0  10
AND   59  80  52  81 /  20   0   0  10
CLT   59  78  50  80 /  20   0   0  10
HKY   56  76  48  78 /  20   0   0  10
AVL   52  73  45  76 /  40   0   0  10

.GSP...
GA...NONE.
NC...NONE.
SC...NONE.

GAZ010-017-018-026-028-029-NCZ033>037-048>059-062>072-082-SCZ001>014-
019-282200-

SEVERE WEATHER OUTLOOK
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
255 PM EDT SUN APR 28 2002

...SEVERE WEATHER THREATENS THIS AFTERNOON AND EVENING...

SEVERE THUNDERSTORMS MOVING THROUGH MIDDLE AND EAST TENNESSEE WERE
HEADED FOR THE NORTH CAROLINA MOUNTAINS AT MID AFTERNOON.  A TORNADO
WATCH HAS ALREADY BEEN ISSUED FOR PARTS OF THE NORTH CAROLINA
MOUNTAINS...AND LATER...THE SEVERE WEATHER COULD MOVE INTO COUNTIES
EAST OF THE MOUNTAINS.  THE BEST CHANCE OF SEVERE WEATHER ALONG AND
EITHER SIDE OF INTERSTATE 40...EAST OF THE MOUNTAINS...WILL BE
DURING THE EVENING HOURS.

THE THREAT OF SEVERE WEATHER IS NOT AS GREAT SOUTH OF THE
MOUNTAINS...IN THE GEORGIA AND SOUTH CAROLINA FOOTHILLS AND
PIEDMONT...BUT CANNOT BE RULED OUT LATER THIS EVENING.

LATEST SURFACE DATA INDICATE THE STORMS MOVING THROUGH
TENNESSEE...TOWARD THE NORTH CAROLINA MOUNTAINS...MAY STRENGTHEN
EVEN MORE DURING THE AFTERNOON.  PEOPLE IN THE TORNADO WATCH AREA
SHOULD BE READY TO MOVE TO A PLACE OF SAFETY IF A WARNING IS
ISSUED...OR SEVERE WEATHER OBSERVED.

JONES