MESOSCALE DISCUSSION 2052
   NWS STORM PREDICTION CENTER NORMAN OK
   0616 PM CDT TUE OCT 02 2007
   
   AREAS AFFECTED...ERN IA
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 022316Z - 030015Z
   
   CONDITIONAL THREAT FOR ISOLATED TORNADOES WILL PERSIST ACROSS ERN IA
   THROUGH ABOUT 03Z. CONVECTIVE TRENDS WILL BE MONITORED FOR A
   POSSIBLE WW.
   
   A STRONG SLY 50+ KT LOW LEVEL JET BENEATH A 70 KT SWLY MID LEVEL JET
   ATTENDING AN EWD ADVANCING SHORTWAVE TROUGH IS RESULTING IN LARGE
   0-1 KM HODOGRAPHS AND STRONG DEEP SHEAR SUPPORTIVE OF SUPERCELLS
   WITH LOW LEVEL MESOCYCLONES ACROSS ERN IA. STORMS ARE EXPECTED TO
   CONTINUE DEVELOPING ALONG AND IN ADVANCE OF COLD FRONT THROUGH ERN
   IA NEXT FEW HOURS. PRIMARY LIMITING FACTOR IS MARGINAL INSTABILITY
   WITH MLCAPE AOB 500 J/KG AND WEAK LAPSE RATES. HOWEVER...RICH LOW
   LEVEL MOISTURE WITH DEWPOINTS NEAR 70 AND LOW LCL HEIGHTS WITHIN THE
   FAVORABLY SHEARED ENVIRONMENT ARE RESULTING IN A CONDITIONAL THREAT
   FOR ISOLATED TORNADOES. CONVECTIVE TRENDS WILL CONTINUE TO BE
   MONITORED...AND IF STORMS DO NOT SHOW A WEAKENING TREND AS THEY MOVE
   EWD INTO A MORE MARGINAL THERMODYNAMIC ENVIRONMENT...A TORNADO WATCH
   WILL LIKELY BE NEEDED.
   
   ..DIAL.. 10/02/2007
   
   
   ATTN...WFO...DVN...
   
   40969080 40879218 42419193 42229032