MESOSCALE DISCUSSION 1051
   NWS STORM PREDICTION CENTER NORMAN OK
   0604 PM CDT SAT MAY 17 2003
   
   AREAS AFFECTED...SRN MS/E LA
   
   CONCERNING...TORNADO WATCH 408...
   
   VALID 172304Z - 180100Z
   
   SEVERE STORMS ACROSS SRN-ERN MS WILL CONTINUE TO HAVE A THREAT FOR
   DAMAGING WINDS AND ISOLATED TORNADOES. LARGE HAIL WILL ALSO BE
   POSSIBLE WITH THE STRONGEST OF CELLS.
   
   A PRE-FRONTAL TROUGH AHEAD OF A COLD FRONT IS MOVING ACROSS WRN MS
   AND IS PROVIDING A FOCUS FOR CONVECTIVE DEVELOPMENT. TWO AREAS OF
   STRONG CONVECTION ARE PRESENT...ONE N OF COLUMBIA AND ONE N OF
   MERIDIAN. THESE SEVERE STORM CLUSTERS ARE MULTICELLULAR DUE TO THE
   MARGINAL DEEP LAYER SHEAR AROUND 30 KT. HOWEVER...LARGE-SCALE
   FORCING AND MODERATE INSTABILITY ARE SUSTAINING A SEVERE THREAT
   ACROSS WW 408. THE MOIST ENVIRONMENT BELOW 700 MB AND DCAPE VALUES
   AROUND 1000 ARE CONDUCIVE FOR DAMAGING WIND GUSTS. ISOLATED
   TORNADOES WILL ALSO BE POSSIBLE WITH UPDRAFTS THAT FORM ALONG
   OUTFLOW BOUNDARIES NEAR REGIONS OF STRONG INFLOW.  
   
   ..BROYLES.. 05/17/2003
   
   
   ATTN...WFO...BMX...MOB...JAN...LIX...
   
   30688948 30429096 30639130 31239107 31789065 32478995
   32758918 32718833 31878827 30998857