MESO: Mesoscale Discussion 0167

ACUS11 KWNS 182008
SWOMCD
SPC MCD 182008
LAZ000-TXZ000-182115-

MESOSCALE DISCUSSION 0167
NWS STORM PREDICTION CENTER NORMAN OK
0208 PM CST MON FEB 18 2013

AREAS AFFECTED...SE TX/SW LA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 182008Z - 182115Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...TSTMS ARE EXPECTED TO CONTINUE THROUGH THE AFTERNOON
ACROSS SE TX WHILE MOVING NEWD INTO SW LA. STORMS MAY BE STRONG
ENOUGH TO PRODUCE SOME ISOLATED SVR HAIL/WINDS BUT THE THREAT SHOULD
BE TRANSIENT...LEADING TO A LOW PROBABILITY OF WATCH ISSUANCE.
ADDITIONALLY...A BRIEF TORNADO OR TWO CANNOT BE RULED OUT BE THE
THREAT APPEARS VERY LOW AT THIS TIME.

DISCUSSION...TSTMS HAVE GRADUALLY STRENGTHENED WITHIN THE WAA REGIME
ACROSS SE TX. CLOUD COVER AND WARM PROFILES HAVE LIMITED INSTABILITY
THUS FAR BUT MID-LEVEL COOLING ASSOCIATED WITH THE APPROACHING
MID-LEVEL TROUGH IS LIKELY CONTRIBUTING TO AT LEAST SOME
DESTABILIZATION. RECENT MESOANALYSIS DEPICTS SBCAPE AROUND 500 J/KG
AND MLCAPE AROUND 250 J/KG. THIS LACK OF INSTABILITY WILL LIKELY
KEEP STORMS SHALLOW AND THE OVERALL SEVERE THREAT LOW.
HOWEVER...DESPITE THIS MODEST INSTABILITY...THE STRONGLY SHEARED
ENVIRONMENT WILL FAVOR ROTATING UPDRAFTS WITH THE POTENTIAL TO
PRODUCE ISOLATED SVR HAIL/WINDS...PARTICULARLY WITH ANY CELL
MERGERS. RECENT RADAR IMAGERY REFLECTS THIS POSSIBILITY WITH
ROTATING STORMS NOTED IN MONTGOMERY AND SAN JACINTO COUNTIES IN SE
TX. ADDITIONALLY...GIVEN THE STRONG SHEAR...A BRIEF/TRANSIENT
TORNADO CANNOT BE RULED OUT BUT THE PROBABILITY IS LOW.

..MOSIER/HART.. 02/18/2013

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...LCH...SHV...HGX...

LAT...LON 29259490 28939552 29419645 30279651 31289526 31669469
32359394 32309322 31779292 30949307 29929360 29259490

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