MESOSCALE DISCUSSION 0249

MESOSCALE DISCUSSION 0249
NWS STORM PREDICTION CENTER NORMAN OK
0402 PM CDT MON MAR 12 2012

AREAS AFFECTED...NERN LA...NRN AND WRN MS...SWRN TN

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 122102Z - 122200Z

A CONDITIONAL THREAT FOR LARGE HAIL/DMGG WINDS WILL EXIST LATE THIS
AFTERNOON AND EVENING ACROSS PORTIONS OF NERN LA...NRN AND WRN
MS...SWRN TN. EXPECTED ISOLATED NATURE OF THE THREAT LIMITS THE NEED
FOR A WW.

20Z VIS SAT IMAGERY SHOWS A MODEST CU FIELD DEVELOPING ALONG A BROAD
LOW-LEVEL THETA-E AXIS /LOCATED ALONG A LINE FROM 35 WSW IER TO 15
ENE OF JBR/. LOW-LEVEL MOISTURE ADVECTION AND HEATING HAVE RESULTED
IN MUCAPE GREATER THAN 1000 J/KG ACROSS THE AREA. ADDITIONALLY...
DEEP LAYER SHEAR NEAR 30 KT IS MARGINALLY FAVORABLE FOR A FEW
ROTATING STORMS. CONSIDERABLE UNCERTAINTY REMAINS REGARDING
CONVECTIVE INITIATION AND THUNDERSTORM COVERAGE. HOWEVER...
INITIATION OF STORMS OVER THE MID-MISSISSIPPI VALLEY MAY BE ENHANCED
BY A WEAK UPPER IMPULSE MOVING EWD ACROSS AR. IF THIS OCCURS AN
ISOLATED THREAT FOR LARGE HAIL AND DMGG WINDS IS POSSIBLE.