MESOSCALE DISCUSSION 1583
   NWS STORM PREDICTION CENTER NORMAN OK
   0503 PM CDT WED AUG 24 2016

   AREAS AFFECTED...SERN INDIANA / W-CNTRL AND SWRN OH

   CONCERNING...TORNADO WATCH 454...

   VALID 242203Z - 242300Z

   THE SEVERE WEATHER THREAT FOR TORNADO WATCH 454 CONTINUES.

   SUMMARY...THERE IS SOME POTENTIAL FOR SUPERCELLS TO MOVE EAST OF
   TORNADO WATCH 454.  CONTINGENT ON SHORT-TERM TRENDS...A WATCH
   EXTENSION-IN-AREA MAY BE NEEDED FOR PARTS OF WRN OH AND/OR SERN
   INDIANA.

   DISCUSSION...RADAR MOSAIC SHOWS WIDELY SCATTERED STORMS ACROSS CNTRL
   INTO N-CNTRL AND NERN INDIANA.  A COUPLE OF THESE STORMS HAVE BEEN
   TORNADIC.  THE AIRMASS DOWNSTREAM OVER WRN OH IS RELATIVELY SIMILAR
   TO ERN INDIANA WITH TEMPS IN THE LOWER 80S AND DEWPOINTS IN THE
   LOWER 70S.  COUPLED WITH ADEQUATE BUOYANCY FOR STRONG
   UPDRAFTS...BOTH OBJECTIVE ANALYSIS DATA AND AREA WSR-88D VAD DATA
   SUGGEST THE DISCUSSION AREA HAS SUFFICIENT DEEP-LAYER SHEAR /30-35
   KT/ FOR SUSTAINING SUPERCELLS.  CONSIDERABLE VEERING AND
   STRENGTHENING OF FLOW IN LOWEST 2 KM AGL --RESULTING IN 200-300
   EFFECTIVE SRH-- IS LIKELY CONTRIBUTING TO LOW-LEVEL STORM ROTATION
   AND TORNADIC SUPERCELL POTENTIAL.  THERE REMAINS SOME QUESTION HOW
   LONG LIVED AND INTENSE THE STORMS IN INDIANA WILL BE ONCE THEY MOVE
   INTO WRN PORTIONS OF OH.  NONETHELESS...IT APPEARS THERE IS
   INCREASING TORNADIC SUPERCELL POTENTIAL AND A PORTION OF THIS AREA
   MAY NEED TO BE CONSIDERED FOR A WATCH EXTENSION-IN-AREA IN THE NEXT
   30-60 MINUTES.

   ..SMITH.. 08/24/2016


   ATTN...WFO...ILN...IWX...IND...

   LAT...LON   39128543 40648441 40768357 40628343 40338349 39208424
               39108485 39128543