MESOSCALE DISCUSSION 0157
NWS STORM PREDICTION CENTER NORMAN OK
0157 PM CST TUE FEB 12 2013

AREAS AFFECTED...SRN LA...SRN MS...SRN AL...WRN FL PANHANDLE

CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY

VALID 121957Z - 122100Z

PROBABILITY OF WATCH ISSUANCE...95 PERCENT

SUMMARY...A THREAT FOR TORNADOES...DMGG WINDS...AND HAIL...IS
EXPECTED TO INCREASE THIS AFTERNOON ACROSS THE CNTRL GULF COAST IN
ASSOCIATION WITH A WEAK SFC CYCLONE AND ATTENDANT WARM FRONT. A
TORNADO WATCH WILL LIKELY BE NEEDED.

DISCUSSION...VISIBLE SATELLITE AND LIGHTNING DATA SHOW CONVECTION
INCREASING INVOF A WEAK SFC LOW...WHICH WAS CENTERED JUST N OF BPT
AS OF 19Z. AN ATTENDANT WARM FRONT PARALLEL TO THE GULF COAST IS
SLOWLY LIFTING NWD ACROSS COASTAL SRN LA...WITH DEWPOINTS OF 65-70 F
SPREADING INLAND. THE 12Z LCH SOUNDING MODIFIED FOR REPRESENTATIVE
19Z SFC CONDITIONS SUGGESTS THAT DEVELOPING CONVECTION ALONG/S OF
THE WARM FRONT WILL LIKELY BE SFC-BASED...WITH SBCAPE VALUES
APPROACHING 1000 J/KG. MODEST HEIGHT FALLS OVERSPREADING THE AREA IN
RESPONSE TO AN UPPER TROUGH CENTERED OVER W TX...COMBINED WITH
FURTHER BOUNDARY LAYER HEATING AND CONVERGENCE ALONG A COLD FRONT
ATTENDANT TO THE SFC LOW...MAY SUPPORT DEVELOPMENT OF TSTMS THIS
AFTERNOON THROUGH SRN LA.

ADDITIONAL SFC-BASED TSTMS MAY DEVELOP INVOF THE WARM FRONT INTO SRN
MS/AL AND EVENTUALLY THE WRN FL PANHANDLE WITHIN A WEAK WAA
REGIME...WHERE FAVORABLE HODOGRAPHS/LOW-LEVEL SHEAR PROFILES /PER
LCH/MOB VWP DATA/ ARE IN PLACE. DEEP-LAYER SHEAR PROFILES ARE
FAVORABLE FOR ISOLATED SUPERCELLS AND SMALL BOWING SEGMENTS...WITH
AN ENHANCED TORNADO THREAT ACCOMPANYING DISCRETE STORMS FORMING NEAR
THE WARM FRONT/SFC LOW. AN ADDITIONAL THREAT OF DMGG WINDS/HAIL MAY
ALSO ACCOMPANY THE STRONGER STORMS.

..ROGERS/MEAD.. 02/12/2013


ATTN...WFO...TAE...BMX...MOB...JAN...LIX...LCH...

LAT...LON 29089053 29229138 29589312 29709354 30099377 30409370
30579329 30709193 30899075 31208997 31398928 32028844
32128678 31898619 31598608 30918584 30518616 30288727
30278884 29858947 29279018 29089053