MESO: Mesoscale Discussion 0979

ACUS11 KWNS 061729
SWOMCD
SPC MCD 061728
LAZ000-TXZ000-061900-

MESOSCALE DISCUSSION 0979
NWS STORM PREDICTION CENTER NORMAN OK
1228 PM CDT THU JUN 06 2013

AREAS AFFECTED...PORTIONS OF SOUTHEAST TX INTO SW LA

CONCERNING...SEVERE POTENTIAL...WATCH LIKELY

VALID 061728Z - 061900Z

PROBABILITY OF WATCH ISSUANCE...80 PERCENT

SUMMARY...THUNDERSTORMS WILL INCREASE ACROSS SE TX INTO SW LA THIS
AFTERNOON. LARGE HAIL AND STRONG WIND GUSTS WILL BE THE MAIN THREAT
WITH SEMI-DISCRETE STORM CLUSTERS. A WW WILL LIKELY BE NEEDED IN THE
NEXT HOUR.

DISCUSSION...THUNDERSTORMS ARE EXPECTED TO CONTINUE TO INCREASE
ACROSS THE MCD AREA THIS AFTERNOON. CURRENTLY...STORMS WERE
DEVELOPING ALONG/NEAR AN OUTFLOW BOUNDARY FROM NEAR POLK COUNTY TX
S/SEWD INTO BEAUREGARD PARISH IN SW LA. THIS OUTFLOW BOUNDARY WAS
INTERSECTING A SFC WIND SHIFT LINE IN THE VICINITY OF THE POLK
COUNTY TX STORM. AGITATED CU FIELD WAS EVIDENT ON VIS SATELLITE
IMAGERY ALONG AND N OF THIS WIND SHIFT LINE TOWARD THE COLD FRONT
LOCATED ACROSS CENTRAL TX. THUNDERSTORMS ARE EXPECTED TO DEVELOP
ALONG THESE BOUNDARIES THROUGH THE DAY. 17Z MESOANALYSIS SHOWED A
WARM/MOIST AIRMASS WITH MODERATE INSTABILITY IN PLACE /APPROACHING
2000-2500 J/KG MLCAPE/. BULK SHEAR VALUES FROM 30-40 KT WILL AID IN
ORGANIZATION OF SEMI-DISCRETE THUNDERSTORM CLUSTERS AND ADEQUATELY
STEEP LAPSE RATES WILL HELP MAINTAIN UPDRAFT STRENGTH...LEADING TO
SEVERE HAIL THREAT. PW VALUES OVER 1.7 INCHES AND DCAPE VALUES
NEARING 1000 J/KG WILL FURTHER INCREASE SEVERE WIND POTENTIAL IN
ADDITION TO HAIL THREAT. GIVEN THESE PARAMETERS AND EXPECTED STORM
DEVELOPMENT...A WW WILL LIKELY BE ISSUED IN THE NEXT HOUR.

..LEITMAN/THOMPSON.. 06/06/2013

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

ATTN...WFO...LCH...HGX...CRP...EWX...

LAT...LON 28779711 29519739 30349678 30779603 30959503 30679437
30559357 30549286 30289267 29869273 29539295 29279347
28129591 28149650 28779711

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