Edited 10:15PM CDT…

   Mesoscale Discussion 1366
   NWS Storm Prediction Center Norman OK
   0947 PM CDT Mon Jul 04 2022

   Areas affected...portions of far eastern Iowa into far southern
   Wisconsin...far northern Illinois and southwestern Lower Michigan

   Concerning...Severe Thunderstorm Watch 432...

   Valid 040947CDT - 041115PM CDT

   The severe weather threat for Severe Thunderstorm Watch 432
   continues.

   SUMMARY...The severe threat continues across Severe Thunderstorm
   Watch 432. Damaging gusts are the main threat, especially with
   merging storms. Large hail also possible and a tornado cannot be ruled
   out.

   DISCUSSION...Warm-air advection and the northward passage of a 500
   mb vort max (in northeastern WI) has allowed for the initiation and
   sustenance of multiple supercells along an east-west line from far
   eastern IA, spanning eastward along the WI/IL border. Given the lack
   of strong deep-layer ascent, low-level lift in the form of warm-air
   advection and the intensification of a low-level jet should sustain
   storms into the evening hours. The ongoing storms are advancing
   south-southeast along an MLCAPE gradient (ranging from 1000-3000
   J/kg) amid 40+ kts of effective bulk shear, suggesting that updrafts
   should remain robust and organized, with a damaging gust/large hail
   threat. 

   Despite the presence of widespread 300+ m2/s2 of effective SRH,
   regional VWPs show modestly curved hodographs in the surface-3 km
   layer, with velocity and shear magnitudes rapidly dropping off
   around 700 mb. In addition, the 850-700 mb layer appears slightly
   neutral in instability on the 00Z observed DVN sounding. As such,
   the vertical shear/MLCINH introduced in this layer may be the main
   limiting factor for a more robust tornado threat. Finally, a locally
   greater damaging gust threat could materialize with any supercells
   that congeal and grow upscale into an MCS. This especially may be
   the case later this evening, when the LLJ veers to more
   west-southwesterly, aligning more parallel with the line of storms.
   As such, the severe threat may spread into southwestern Lower
   Michigan, where a WW issuance may eventually be needed.