MESOSCALE DISCUSSION 0755
   NWS STORM PREDICTION CENTER NORMAN OK
   0509 PM CDT TUE MAY 08 2007
   
   AREAS AFFECTED...NCENTRAL/NWRN TX...SWRN/SCENTRAL OK
   
   CONCERNING...SEVERE THUNDERSTORM WATCH 258...
   
   VALID 082209Z - 082345Z
   
   THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 258
   CONTINUES.
   
   CLUSTER OF SUPERCELLS HAVE EXHIBITED MODERATE LOW-MID LEVEL ROTATION
   ACROSS NRN PORTIONS OF WW 258. AREAS NORTH OF I-20 ARE BEING
   MONITORED FOR A POTENTIAL REPLACEMENT TORNADO WATCH.
   
   LATEST SFC ANALYSIS SHOWS A BOUNDARY EXTENDING FROM NEAR ABI NEWD TO
   NEAR GAINESVILLE TX. NORTH OF THIS BOUNDARY...NEAR SFC FLOW WAS ELY
   AROUND 10 TO 15 KTS. JUST ABOVE THE SFC LAYER A MODEST LOW LEVEL JET
   HAS DEVELOPED IN RESPONSE TO AN APPROACHING MCS OVER WRN TX. THIS
   HAS RESULTED IN MODERATE LOW LEVEL SHEAR / 75-100 M2/S2 OF 0-1 KM
   SRH/ NORTH OF THIS BOUNDARY. COMBINED WITH MODERATE INSTABILITY
   /MLCAPES AROUND 1500 J/KG/...3KM CAPE VALUES /100-125 J/KG/ AND LOW
   LCL HEIGHTS AN ISOLATED TORNADO THREAT MAY PERSIST WITH DISCRETE
   SUPERCELLS THAT HAVE DEVELOPED AHEAD OF THE MCS. SOUTH OF THE
   OUTFLOW BOUNDARY...WEAKER LOW LEVEL SHEAR AND APPROACHING CONVECTIVE
   LINE WILL SUPPORT MAINLY A DMGG WIND THREAT.
   
   ..CROSBIE.. 05/08/2007
   
   
   ATTN...WFO...FWD...OUN...SJT...
   
   34829809 35069876 35089905 34779915 34649949 34389985
   33569977 33089966 32629997 32559943 32829831 33539744
   34659765 34659806