MESOSCALE DISCUSSION 0744
   NWS STORM PREDICTION CENTER NORMAN OK
   0259 AM CDT TUE MAY 21 2013
   
   AREAS AFFECTED...SRN IND...SWRN OH...FAR SRN IL...FAR SERN MO...AND
   FAR WRN KY
   
   CONCERNING...TORNADO WATCH 197...
   
   VALID 210759Z - 210930Z
   
   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 197 CONTINUES.
   
   SUMMARY...POTENTIAL FOR A CONTINUED EWD SEVERE WEATHER THREAT
   /PRIMARILY DAMAGING WINDS/ EXISTS INTO PARTS OF SERN-EAST CENTRAL
   IND EARLY THIS MORNING...AND THUS WW 197 HAS BEEN EXPANDED EWD BY
   WFO IND. COUNTIES CAN BE REMOVED FROM THIS WW WITH THE PASSAGE OF
   THE TSTM LINE.
   
   FAR SERN-EAST CENTRAL IND INTO SWRN OH WILL CONTINUE TO BE MONITORED
   FOR A SVR WEATHER THREAT /LOCALLY STRONG WIND GUSTS/ AND THE
   POTENTIAL NEED FOR A NEW WW AS THE LINE OF STORMS IN IND ADVANCES
   EWD.
   
   DISCUSSION...REGIONAL RADAR IMAGERY SHOWED A LINE OF TSTMS EXTENDING
   NEARLY N-S FROM NORTH CENTRAL TO SOUTH CENTRAL IND...WITH THIS
   ACTIVITY THEN TRAILING SWWD THROUGH SWRN IND INTO FAR SRN IL.  CLOUD
   TOPS ACROSS MUCH OF WW 197 ARE WARMING...CAPPI RADAR IMAGERY SHOWS A
   WEAKENING TREND...AND LIGHTNING COVERAGE IS DIMINISHING WITH THE
   CONVECTION IN CENTRAL/SRN IND.  THESE FACTORS SUGGEST THE OVERALL
   SEVERE WEATHER THREAT SHOULD CONTINUE TO WANE.  HOWEVER...A 50 KT
   WLY REAR INFLOW JET OBSERVED AT WSR-88D IND AT 0730Z AND DOWNSTREAM
   MODERATE INSTABILITY WILL SUPPORT A CONTINUED EWD ADVANCEMENT OF THE
   CONVECTIVE LINE INTO SWRN OH BY 09Z.  RECENT SURFACE OBSERVATIONS IN
   CENTRAL IND INDICATED SUB-SEVERE WIND GUSTS...AND THUS MAY BE
   REFLECTING THE LACK OF BETTER SUPPORT FOR A SUSTAINED BOW.
   
   ..PETERS/HART.. 05/21/2013
   
   
   ATTN...WFO...ILN...LMK...IWX...IND...PAH...
   
   LAT...LON   36648988 38148904 38178820 38558722 39348658 40448654
               40458441 39608426 38988471 38628607 38048692 37138777
               36508824 36648988