US Mesoscale Discussions

Storm Prediction Center Mesoscale Discussion 1499

Published Date and Time: 2026-07-04 17:58:00



   Mesoscale Discussion 1499
   NWS Storm Prediction Center Norman OK
   0456 PM CDT Sat Jul 04 2026

   Areas affected...Eastern Missouri into southern Illinois and
   adjacent portions of Kentucky and Indiana

   Concerning...Severe Thunderstorm Watch 454...

   Valid 042156Z - 050000Z

   The severe weather threat for Severe Thunderstorm Watch 454
   continues.

   SUMMARY...Some threat for severe winds will likely spread east into
   southern Illinois in the coming hours as a loosely organized MCS
   exits eastern Missouri. However, the need for downstream watch
   issuance is uncertain due to a very modest kinematic environment.

   DISCUSSION...Latest radar imagery from KLSX shows a loosely
   organized, and predominantly outflow dominant, MCS pushing eastward
   across eastern MO and into far western IL. Wind gusts over the past
   hour have mostly been in the 30-50 mph range, but velocity imagery
   continues to show embedded swaths of stronger winds capable of
   producing wind damage. Downstream, clustered convection continues to
   percolate across southern IL within the regional buoyancy maximum.
   However, regional VWPs continue to show very limited flow through
   much of the column, which is resulting in outflow-dominant
   convection with limited intensities. Consequently, confidence is
   limited that the ongoing MCS will pose a substantial and/or
   widespread wind threat downstream as it moves into southern IL.
   Similarly, the potential for downstream watch issuance is uncertain.
   That said, the favorable buoyancy will likely promote continued
   development along the leading outflow boundary with the potential
   for transient and localized swaths of strong (to perhaps severe)
   downburst winds through mid/late evening.

   ..Moore.. 07/04/2026

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

   ATTN...WFO...IND...PAH...ILX...LSX...

   LAT...LON   37439086 37879032 38369004 38809003 39019001 39168962
               39258758 39088732 38828725 38458728 38108745 37708781
               37358833 37268853 37439086 

   MOST PROBABLE PEAK WIND GUST...UP TO 60 MPH



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