DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 261939
SWODY1
SPC AC 261937

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0137 PM CST MON DEC 26 2011

VALID 262000Z - 271200Z

...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF SRN AL AND NWRN
FL...

...SRN AL/NWRN FL...
WILL MAINTAIN THREAT FOR A FEW STRONG/SEVERE STORMS OVER THIS AREA
FOR LATER TONIGHT AS STRONG UPPER TROUGH MOVES EWD TOWARD THE LOWER
MS VALLEY. LATEST SURFACE DATA INDICATE WARM FRONT IS LIFTING NWD
TO JUST SOUTH OF THE SERN LA COAST...AND AS THIS FEATURE MOVES
INLAND TONIGHT POTENTIAL FOR SURFACE-BASED STORMS OVER COASTAL
SECTIONS WILL INCREASE. MARGINAL LAPSE RATES/INSTABILITY ARE
EXPECTED TO LIMIT OVERALL SEVERE THREAT BUT ISOLATED WIND DAMAGE
AND/OR A BRIEF TORNADO OR TWO WILL BE POSSIBLE GIVEN STRENGTHENING
LOW- AND DEEP LAYER SHEAR.

..WEISS.. 12/26/2011

.PREV DISCUSSION... /ISSUED 0948 AM CST MON DEC 26 2011/

MORNING WATER VAPOR LOOPS SHOW A WELL-DEFINED UPPER LOW OVER THE TX
PANHANDLE. THIS SYSTEM IS EXPECTED TO BECOME PROGRESSIVE TODAY AND
TRACK EASTWARD INTO THE MID MS VALLEY BY TUE MORNING. AS THE SYSTEM
APPROACHES...A RAPID INCREASE IN SOUTHERLY LOW LEVEL WINDS IS
EXPECTED OVER THE GULF OF MEXICO. VISIBLE SATELLITE IMAGERY SHOWS
THE MAIN SURFACE BOUNDARY LIES ABOUT 100 MI SOUTH OF THE MS/AL
COAST. THIS BOUNDARY WILL RETURN NORTHWARD THIS EVENING AND
TONIGHT...BRINGING A THREAT OF LOCALLY SEVERE STORMS TO PARTS OF THE
CENTRAL/EASTERN GULF COAST REGION.

PRESENT INDICATIONS ARE THAT RICH LOW LEVEL MOISTURE WILL NOT MAKE
IT VERY FAR INLAND BEFORE THE COLD FRONT SWEEPS ACROSS AREA.
HOWEVER...FORECAST SOUNDINGS FOR 06-12Z TONIGHT FROM MOB EASTWARD TO
NEAR TLH SHOW VERY FAVORABLE LOW LEVEL AND DEEP LAYER VERTICAL SHEAR
FOR SUPERCELL STORM STRUCTURES. EVEN WITH MID-UPPER 60S DEWPOINTS
MAKING IT ONSHORE...INSTABILITY WILL BE QUITE LIMITED WITH MLCAPE
VALUES OF ONLY 200-300 J/KG. NEVERTHELESS...THE STRENGTH OF THE
WIND FIELDS AND FAVORABLE DYNAMIC FORCING PROVIDE SUFFICIENT
EVIDENCE TO ADD A SMALL SLIGHT RISK TO THIS AREA. LOCALLY DAMAGING
WINDS OR A BRIEF TORNADO OR TWO APPEAR TO BE THE MAIN THREATS.

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