SPC AC 060521
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1221 AM CDT MON OCT 06 2008
VALID 061200Z - 071200Z
...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE SRN
PLAINS...
...SYNOPSIS...
A LARGE MID-LEVEL TROUGH IS FORECAST TO MOVE EWD OUT OF THE
ROCKIES/ACROSS THE CENTRAL U.S. THIS PERIOD...WITH A FAIRLY LARGE
AREA OF EMBEDDED VORTICITY PROGGED TO SPREAD ACROSS THE SRN PLAINS.
MEANWHILE...A SECOND/SMALLER TROUGH IS FORECAST TO VACATE THE NERN
CONUS.
AT THE SURFACE...A LOW ASSOCIATED WITH THE SRN PLAINS VORT MAX
SHOULD DRIFT NEWD ACROSS OK...WHILE A WEAK/TRAILING COLD FRONT
SHIFTS EWD ACROSS TX THROUGH THE PERIOD. THIS COMBINED WITH A
MOISTENING WARM SECTOR ACROSS THE SRN PLAINS WILL RESULT IN A FAIRLY
WIDESPREAD AREA OF ACTIVE CONVECTION THROUGH THE PERIOD.
...NERN QUARTER OF TX/S CENTRAL AND SERN OK/SWRN AR...
WIDESPREAD AREA OF SHOWERS AND THUNDERSTORMS -- INITIALLY FORECAST
OVER CENTRAL PORTIONS OF TX/OK -- IS EXPECTED TO SPREAD SLOWLY EWD
THROUGH THE DAY. THIS ONGOING CONVECTION AND ASSOCIATED CLOUD COVER
COMPLICATES THE FORECAST...AS HEATING/DESTABILIZATION WILL LIKELY BE
HINDERED ACROSS A LARGE AREA. ATTM...IT APPEARS THAT MARGINAL
DESTABILIZATION MAY OCCUR ALONG WRN FRINGES OF THIS AREA OF
PRECIPITATION DURING THE AFTERNOON -- ACROSS CENTRAL TX/CENTRAL OK
-- WHICH SHOULD SUPPORT NEW CONVECTIVE DEVELOPMENT INVOF THE SURFACE
LOW/FRONT.
WITH LOW-LEVEL FLOW VEERING WITH HEIGHT AND INCREASING TO 40-PLUS KT
AT MID LEVELS...SHEAR WOULD SUPPORT ORGANIZED/ROTATING STORMS.
AGAIN HOWEVER...QUESTIONS PERSIST REGARDING POTENTIAL FOR
DESTABILIZATION ACROSS A LARGE PORTION OF THE WARM SECTOR.
ATTM...IT APPEARS THAT THREAT FOR HAIL/LOCALLY-DAMAGING WINDS IS
SUFFICIENT TO SUPPORT THE INTRODUCTION OF A SLIGHT RISK THIS
FORECAST...ACROSS THE NERN QUARTER OF TX AND INTO SRN OK/SWRN AR.
PRIMARY SEVERE POTENTIAL SHOULD EXIST FROM LATE AFTERNOON THROUGH
THE EVENING...WITH HAIL AND LOCALLY-DAMAGING GUSTS THE MAIN THREATS.
..GOSS.. 10/06/2008
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NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1300Z
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