SPC AC 290104

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0804 PM CDT Wed Jul 28 2021

   Valid 290100Z - 291200Z

   ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS OVER A PORTION
   OF THE UPPER MIDWEST AND GREAT LAKES REGION...

   ...SUMMARY...
   Widespread severe storms with occasional significant severe wind
   damage are expected this evening into tonight along a corridor from
   northeastern Minnesota across Wisconsin to southwest Lower Michigan.

   ...Upper Midwest and Great Lakes region...

   As of early evening, robust surface-based thunderstorm initiation is
   underway in several areas across the Upper Midwest including along a
   cold front over northeast MN as well as along a pre-frontal boundary
   across northwest WI. Storms are expected to increase in coverage
   this evening over northern WI in response to an strengthening
   southwesterly low-level jet coupled with a low-amplitude shortwave
   trough moving southeast along the northern periphery of an upper
   ridge. Some of the initial storms may exhibit supercell
   characteristics given 45+ kt effective bulk shear and 3000+ J/kg
   MLCAPE. Very large hail and isolated tornadoes are possible mainly
   through mid-evening. However, storms should eventually congeal into
   a forward-propagating MCS with line/bowing segments and spread
   southeast along the instability gradient. Widespread damaging wind
   (some significant) and possibly a few QLCS tornadoes should become
   the main threats later this evening into the overnight.

   ..Dial.. 07/29/2021

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