SPC AC 050551
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1251 AM CDT FRI SEP 05 2008
VALID 051200Z - 061200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN HIGH
PLAINS...
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE ERN
CAROLINAS AND SE VA...
...TX PANHANDLE/WRN OK...
A BROAD UPPER-LEVEL TROUGH WILL BE IN PLACE ACROSS THE NCNTRL STATES
AS A SHORTWAVE TROUGH MOVES SEWD OUT OF THE CNTRL ROCKIES INTO THE
HIGH PLAINS TODAY. AT THE SFC...A LOW IS FORECAST TO DEVELOP ACROSS
NERN NM WITH A MOIST AXIS LOCATED FROM NCNTRL TX EXTENDING NWWD INTO
THE TX PANHANDLE WITH SFC DEWPOINTS IN THE UPPER 50S F. A NARROW
CORRIDOR OF INSTABILITY IS FORECAST TO EXIST BY AFTERNOON FROM ERN
NM NNEWD ACROSS THE TX PANHANDLE WITH SCATTERED SFC-BASED
THUNDERSTORMS INITIATING BY LATE AFTERNOON. ALTHOUGH MODEL FORECASTS
VARY ON THE EXACT LOCATION...THE FORECASTS ARE IN GENERAL AGREEMENT
ORGANIZING A STORM CLUSTER OR SMALL MCS AHEAD OF THE SHORTWAVE
TROUGH IN THE TX PANHANDLE AND WRN OK BY EARLY EVENING.
CONCERNING THE SHEAR ENVIRONMENT...FORECAST SOUNDINGS BY LATE
AFTERNOON SHOW 0-6 KM SHEAR VALUES AROUND 50 KT ACROSS MUCH OF THE
SLIGHT RISK AREA WHICH SHOULD BE SUPPORTIVE OF SUPERCELL
DEVELOPMENT. A PLUME OF STEEP MID-LEVEL LAPSE RATES SHOULD BE IN
PLACE ACROSS THE REGION AND THIS COMBINED WITH THE STRONG SHEAR
PROFILES WILL BE FAVORABLE FOR LARGE HAIL. IN ADDITION...FORECAST
SOUNDINGS SHOW STRONGLY VEERED LOW-LEVEL WINDS WITH SUBSTANTIAL
SPEED SHEAR SUGGESTING AN ISOLATED TORNADO THREAT MAY DEVELOP AS
WELL. ALTHOUGH WIND DAMAGE MAY INITIALLY BE THE LESSER
THREAT...DAMAGING WIND GUSTS WILL ALSO BE POSSIBLE ESPECIALLY IF A
BOWING SEGMENT CAN ORGANIZE ACROSS THE SLIGHT RISK AREA BY EARLY
EVENING.
...ERN CAROLINAS/FAR SE VA...
TROPICAL STORM HANNA IS FORECAST BY THE NATIONAL HURRICANE CENTER TO
MOVE NWD TOWARD THE CAROLINAS TODAY AND APPROACH THE COASTAL
SECTIONS OF SRN NC TONIGHT. MODEL FORECASTS SPREAD RAINBANDS NORTH
OF THE CENTER OF HANNA INTO ERN SC THIS EVENING WITH THE OUTER BANDS
MOVING NNEWD ACROSS ERN NC DURING THE OVERNIGHT PERIOD. A 40 TO 50
KT LOW-LEVEL JET IN THE ERN QUADRANT OF HANNA WILL RESULT IN STRONG
LOW-LEVEL SHEAR /0-1 KM SHEAR VALUES OF 25 TO 35 KTS/ ACROSS MUCH OF
THE ERN CAROLINAS TONIGHT. THIS ALONG WITH LOW LCL HEIGHTS AND
ABUNDANT LOW-LEVEL MOISTURE SHOULD BE FAVORABLE FOR ROTATING STORMS
WITH TORNADO POTENTIAL. THE TORNADO THREAT SHOULD SPREAD NWD ACROSS
ERN NC AFTER MIDNIGHT AS LOW-LEVEL SHEAR INCREASES WITH THE APPROACH
OF HANNA. A MARGINAL WIND DAMAGE THREAT MAY ALSO EXIST WITH THE MORE
INTENSE CELLS EMBEDDED IN THE RAINBANDS OF HANNA.
..BROYLES/SMITH.. 09/05/2008
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NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
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