MESOSCALE DISCUSSION 2242
NWS STORM PREDICTION CENTER NORMAN OK
1012 PM CST WED DEC 19 2007
AREAS AFFECTED...SERN TX INTO SWRN LA
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 200412Z - 200545Z
A CONTINUED INCREASE IN STORM COVERAGE AND INTENSITY IS EXPECTED
THROUGH 06Z. ISOLATED HAIL AND/OR LOCALLY DAMAGING WINDS WILL BE
THE PRIMARY SEVERE WEATHER HAZARDS...THOUGH A TORNADO OR TWO IS
POSSIBLE. CONVECTIVE TRENDS ARE BEING MONITORED FOR A POSSIBLE WW.
A RAPID INCREASE IN TSTM DEVELOPMENT HAS OCCURRED OVER THE PAST HALF
HOUR OVER SERN TX FROM NEAR TO UTS TO N OF LFK. WATER VAPOR
IMAGERY...RUC DIAGNOSTIC FIELDS AND REGIONAL VWP/PROFILER DATA ALL
SUGGEST THAT DEEP LAYER FORCING FOR ASCENT IS RAPIDLY STRENGTHENING
ACROSS AREA...LIKELY CONTRIBUTING TO THIS INCREASE IN CONVECTIVE
DEVELOPMENT. THESE STORMS APPEAR TO BE DEVELOPING ALONG THE ERN
EDGE OF STRONGER CAPPING OBSERVED BY 00Z S TX SOUNDINGS WITHIN A
MOIST LOW-LEVEL ENVIRONMENT CHARACTERIZED BY DEWPOINTS IN THE
LOW/MID 60S AND MLCAPES OF 300-800 J/KG.
CURRENTLY...IT APPEARS THE MARGINAL INSTABILITY IS INHIBITING STORM
ORGANIZATION WITH MAJORITY OF ACTIVITY LIKELY SLIGHTLY ELEVATED.
HOWEVER WITH TIME...A FEW OF THE MORE INTENSE STORMS MAY BECOME
SURFACE-BASED WITHIN A RATHER STRONGLY SHEARED KINEMATIC ENVIRONMENT
WITH EFFECTIVE BULK SHEARS OF 45-55 KT AND EFFECTIVE SRH VALUES OF
250-350 M2/S2. LOCALLY DAMAGING WINDS AND SEVERE HAIL WILL BE THE
PRIMARY HAZARDS...THOUGH A TORNADO OR TWO WILL BE POSSIBLE WITH ANY
SUSTAINED SUPERCELLS.
..MEAD.. 12/20/2007
ATTN...WFO...LCH...SHV...HGX...FWD...
29539594 29989637 31039637 31829591 32149495 32109426
31899363 31459293 30549277 30069308 29719401 29379518
