SPC AC 131724
DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1124 AM CST FRI FEB 13 2009
VALID 141200Z - 151200Z
...NO SVR TSTM AREAS FORECAST...
...SYNOPSIS...
A PROGRESSIVE/RELATIVELY LOW AMPLITUDE FLOW REGIME WILL PERSIST OVER
THE CONUS THROUGH SATURDAY. LOOSELY TIED TO A SHORTWAVE TROUGH OVER
THE MIDWEST/GREAT LAKES REGION...A WEAK SURFACE LOW WILL SPREAD
EASTWARD ACROSS THE CENTRAL/SOUTHERN APPALACHIANS...WITH AN
ASSOCIATED COLD FRONT ADVANCING SOUTHEASTWARD ACROSS THE GULF COAST
REGION. THIS FRONTAL ZONE WILL SERVE AS THE GENERAL FOCUS FOR TSTM
POTENTIAL ON SATURDAY.
...CENTRAL/EASTERN GULF COAST STATES THROUGH AFTERNOON...
AHEAD OF A COLD FRONT...SCATTERED/NUMEROUS SHOWERS AND TSTMS WILL BE
ONGOING SATURDAY MORNING ACROSS THE EAST-CENTRAL GULF COAST REGION
AMIDST A MODEST LOW LEVEL THETA-E ADVECTION/ISENTROPIC LIFT REGIME.
THIS ACTIVITY SHOULD DEVELOP EASTWARD ACROSS AL/GA AND NORTH FL
DURING THE DAY AS THE LOW LEVEL JET SHIFTS EASTWARD/WEAKENS BY
AFTERNOON. GIVEN PLENTIFUL EARLY DAY CLOUD COVER/PRECIPITATION AND
MODEST MOISTURE INLAND /ESPECIALLY NORTH OF THE WEST-EAST MARINE
BOUNDARY/...THE PRIMARY POTENTIAL FOR SURFACE BASED TSTMS AND ANY
ASSOCIATED SEVERE RISK WILL BE ACROSS SOUTHERN AL/SOUTHERN
GA/NORTHERN FL WHERE SURFACE DEWPOINTS WILL GENERALLY BE IN THE
LOWER 60S F. WITH SBCAPE IN THE WARM SECTOR LIKELY TO BE LIMITED TO
500-750 J/KG...35-45 KT OF DEEP LAYER/LARGELY DIRECTIONAL FLOW WILL
FAVOR SPLITTING UPDRAFTS/POSSIBLY SOME SMALL SCALE BOWING. ISOLATED
STRONG WIND GUSTS AND PERHAPS HAIL/BRIEF TORNADO WILL BE A
POSSIBILITY THROUGH THE AFTERNOON...BUT THE OVERALL SEVERE RISK IS
EXPECTED TO REMAIN QUITE ISOLATED/MARGINAL.
...SOUTH CENTRAL/SOUTHEAST TX TO LA LATE AFTERNOON/NIGHT...
THE SHALLOW SURFACE FRONT SHOULD STEADILY ADVANCE SOUTHWARD TO THE
WESTERN GULF DURING THE DAY. IN THE WAKE OF/NORTH OF THE SHALLOW
SURFACE FRONT...ISENTROPIC LIFT/WARM ADVECTION...PERHAPS AIDED BY A
WEAK MID LEVEL IMPULSE AND/OR AGEOSTROPHIC RESPONSE TO A
STRENGTHENING/PERTURBED SUBTROPIC JET...SHOULD CONTRIBUTE TO
ELEVATED TSTM DEVELOPMENT ACROSS PORTIONS OF SOUTH CENTRAL/SOUTHEAST
TX BY LATE AFTERNOON/EARLY EVENING. GIVEN AMPLE SHEAR/POTENTIAL FOR
UPDRAFT ROTATION...COOL THERMAL PROFILES ALOFT/RELATIVELY STEEP MID
LEVEL LAPSE RATES AND ELEVATED MUCAPE UP TO 750-1000 J/KG MAY
SUPPORT A RISK OF HAIL WITH THE STRONGER TSTMS. HOWEVER...A
RELATIVELY MODEST LOW LEVEL JET /25 KT/ AND MARGINAL ELEVATED
BUOYANCY SUGGEST THE SEVERE THREAT SHOULD REMAIN ISOLATED/MARGINAL
IN NATURE.
..GUYER.. 02/13/2009
CLICK TO GET WUUS02 PTSDY2 PRODUCT
NOTE: THE NEXT DAY 2 OUTLOOK IS SCHEDULED BY 0700Z
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