MESOSCALE DISCUSSION 0242

MESOSCALE DISCUSSION 0242
   NWS STORM PREDICTION CENTER NORMAN OK
   0247 PM CDT SUN MAR 11 2012
   
   AREAS AFFECTED...ERN TX THROUGH WRN LA
   
   CONCERNING...TORNADO WATCH 71...
   
   VALID 111947Z - 112145Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 71 CONTINUES.
   
   THREAT FOR ISOLATED TORNADOES AND DAMAGING WIND WILL PERSIST THIS
   AFTERNOON FROM SERN TX INTO WRN LA. THE GREATEST RISK FOR ISOLATED
   TORNADOES THROUGH 22Z IS EXPECTED FROM SERN TX NEWD THROUGH SWRN AND
   CNTRL LA.
   
   STORMS DEVELOPING ALONG PRE-FRONTAL CONVERGENCE AXIS FROM EXTREME NW
   LA INTO SERN TX CONTINUE TO SHOW OCCASIONAL UPDRAFT ROTATION AND
   LEWP STRUCTURES...BUT SO FAR HAVE MOSTLY REMAINED BELOW SEVERE
   LEVELS. PRIMARY LIMITING FACTOR HAS BEEN WEAK LOW-MID LEVEL LAPSE
   RATES WHICH HAVE RESULTED IN MARGINAL INSTABILITY AND MODEST UPDRAFT
   ACCELERATIONS. NEVERTHELESS...0-1 KM HODOGRAPHS WITH 200-250 M2/S2
   STORM RELATIVE HELICITY AND LOW LCLS WILL REMAIN SUFFICIENT FOR A
   THREAT OF ISOLATED TORNADOES AS THE LLJ SHIFTS SLOWLY NEWD THROUGH
   THETA-E AXIS ACROSS WRN CNTRL LA NEXT FEW HOURS.