Mesoscale Discussion 1339
   NWS Storm Prediction Center Norman OK
   1241 PM CDT Thu Jun 29 2023

   Areas affected...central and eastern Illinois into Indiana

   Concerning...Severe Thunderstorm Watch 415...

   Valid 291741Z - 291945Z

   The severe weather threat for Severe Thunderstorm Watch 415
   continues.

   SUMMARY...It is possible that an initially well-organized convective
   system may undergo substantive weakening within the next hour or
   two, but potential for strong to severe surface gusts could continue
   across and east of the Illinois/Indiana state border.  A new severe
   weather watch may be needed east of WW 415.

   DISCUSSION...A well organized mesoscale convective system, with an
   MCV and strong rear inflow evident in radar imagery, has generally
   maintained considerable intensity across and east of the Mississippi
   River, with gusts at a number of observing sites approaching or
   exceeding 50 kts.  Activity is propagating eastward at 50-55 kt and,
   based on objective analysis, easterly near-surface inflow may
   rapidly begin to become less unstable, at least near its current
   apex which will progress across the remainder of east central
   Illinois, toward the Indianapolis area, through 19-20Z.  

   It remains somewhat unclear how this will impact the subsequent
   convective evolution.  However, a corridor of stronger
   destabilization through northeastern Illinois may maintain vigorous
   thunderstorm development northeast through north of the MCV, with
   additional strong thunderstorm development possibly becoming focused
   along an outflow boundary intersection across southern Illinois into
   the lower Ohio Valley.

   ..Kerr.. 06/29/2023

   ...Please see www.spc.noaa.gov for graphic product...

   ATTN...WFO...IWX...IND...PAH...LOT...ILX...LSX...DVN...

   LAT...LON   41348950 42348766 40988638 39268669 38608760 37738887
               38758950 40478860 41348950