MESOSCALE DISCUSSION 0433
   NWS STORM PREDICTION CENTER NORMAN OK
   1156 PM CDT THU APR 14 2011
   
   AREAS AFFECTED...N-CNTRL/NERN TX AND NWRN LA
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 137...138...
   
   VALID 150456Z - 150630Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH
   137...138...CONTINUES.
   
   CONVECTION WILL CONTINUE BUILDING SWD ACROSS N-CNTRL TX IN RESPONSE
   TO STRONG LOW-LEVEL CONVERGENCE ALONG A COLD FRONT OVERTAKING A
   DRYLINE. THE COMBINATION OF MLCAPE VALUES OF 1000-2000 J/KG AND
   EFFECTIVE BULK SHEAR MAGNITUDES AOA 50 KT IMMEDIATELY AHEAD OF THE
   FRONT WILL PROMOTE ORGANIZED LINEAR CONVECTIVE STRUCTURES WITH AN
   ATTENDANT THREAT FOR DMGG WINDS AND LARGE HAIL. WHILE EFFECTIVE SRH
   VALUES AOA 300 M2/S2 COULD SUPPORT A BRIEF TORNADO THREAT...THE
   UNDERCUTTING NATURE OF THE SYNOPTIC BOUNDARY AND ANTICIPATED LINEAR
   CONVECTIVE MODE WILL BE ASSOCIATED WITH DMGG STRAIGHT-LINE WINDS AS
   THE PRIMARY THREAT. LARGE HAIL WILL ALSO BE A CONCERN WITH STEEP
   MID-LEVEL LAPSE RATES AROUND 8 C/KM IMPINGING ON THE DEVELOPING
   CONVECTION. STRONG WLY CLOUD-BEARING FLOW WILL ALLOW STORMS TO
   SPREAD INTO NERN TX AND EVENTUALLY NWRN LA DURING THE OVERNIGHT
   HOURS...AND THUS SVR TSTM WATCH 138 HAS BEEN ISSUED DOWNSTREAM OF WW
   137.
   
   ..COHEN.. 04/15/2011
   
   
   ATTN...WFO...SHV...FWD...
   
   LAT...LON   31879396 31729450 31639528 31399631 31629717 32169728
               33009642 33049571 33019477 33109433 33159389 33099339
               32749325 32459333 32209352 31879396