MESOSCALE DISCUSSION 0448
   NWS STORM PREDICTION CENTER NORMAN OK
   1144 PM CDT SAT APR 11 2009
   
   AREAS AFFECTED...EDWARD PLATEAU REGION INTO NORTH CENTRAL TX
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 140...
   
   VALID 120444Z - 120615Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 140
   CONTINUES.
   
   TRENDS WILL CONTINUE TO BE MONITORED...BUT A NEW WW MAY NOT BE
   NEEDED AT 06Z EXPIRATION.
   
   PERHAPS THE MOST SIGNIFICANT IMPULSE EMBEDDED WITHIN THE BROADER
   SCALE UPPER TROUGH ACROSS THE PLATEAU REGION APPEARS TO NOW BE
   GRADUALLY PROGRESSING THROUGH THE BASE OF THE TROUGH...TOWARD
   SOUTHWEST TEXAS.  AS THIS MOTION CONTINUES...DOWNSTREAM BANDS OF
   CONVECTION ARE EXPECTED TO CONTINUE TO EVOLVE AND SLOWLY SPREAD
   ACROSS THE SOUTHERN PLAINS.  THE LEADING EDGE OF THE STRONGER
   MID-LEVEL COOLING SEEMS LIKELY TO REMAIN THE FOCUS FOR THE STRONGEST
   STORMS...EAST OF THE BIG BEND REGION INTO NORTH CENTRAL TEXAS
   THROUGH 06-09Z.  WITH THE LOW-LEVEL ENVIRONMENT COOLING ACROSS THE
   HIGH PLAINS...AND LIKELY TO REMAIN RELATIVELY COOL ACROSS MUCH OF
   CENTRAL/NORTHERN TEXAS...STEEP LAPSE RATES ARE EXPECTED TO BE
   CONFINED MAINLY TO THE MID-LEVELS.  BUT...LOWER/MID TROPOSPHERIC
   MOISTENING WITHIN A BROAD ZONE OF ISENTROPIC ASCENT MAY CONTRIBUTE
   TO SUFFICIENT INSTABILITY TO SUPPORT A CONTINUING RISK FOR
   MARGINALLY SEVERE HAIL INTO/THROUGH THE OVERNIGHT HOURS.
   
   ..KERR.. 04/12/2009
   
   
   ATTN...WFO...FWD...OUN...EWX...SJT...MAF...
   
   LAT...LON   29900194 32070022 32749932 33889827 33899721 31929806
               30449930 29440092 29900194