Storm Prediction Center Mesoscale Discussion 1372

   Mesoscale Discussion 1372
   NWS Storm Prediction Center Norman OK
   1256 PM CDT Sat Jun 22 2024

   Areas affected...Portions of northeastern IA...northern IL...and
   southern WI

   Concerning...Severe potential...Watch likely 

   Valid 221756Z - 222000Z

   Probability of Watch Issuance...95 percent

   SUMMARY...Severe storms capable of producing damaging winds, a
   couple tornadoes, and isolated large hail are expected this
   afternoon into the evening. A watch is likely in the next hour or
   two.

   DISCUSSION...Latest visible satellite imagery indicates filtered
   diurnal heating/destabilization of a very moist boundary layer
   (middle 70s dewpoints) along/south of an east/west-oriented
   stationary boundary extending across portions of northern IA into
   southern WI. Over the next couple hours, a weak frontal wave
   currently near far northwest IA will track eastward along the
   boundary, promoting scattered thunderstorm development -- aided by
   the aforementioned destabilization and modest midlevel height falls
   ahead of a midlevel trough. 

   Around 50 kt of midlevel westerly flow atop a 30-40-kt southwesterly
   low-level jet (per regional VWP) will promote organized
   surface-based storms (including a few supercells) near the boundary.
   Easterly storm motions and deep-layer shear parallel to the boundary
   may favor congealing cold pools and localized upscale growth, though
   the favorable shear profile (large clockwise-curved low-level
   hodographs) should encourage a few sustained semi-discrete
   supercells. Damaging winds up to 70 mph, a couple tornadoes, and
   isolated large hail are all possible with this activity. Current
   thinking is that severe storms will develop/mature in the 19-20Z
   time frame and persist into the evening hours. A watch is likely for
   parts of the area in the next hour or two.

   ..Weinman/Hart.. 06/22/2024

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

   ATTN...WFO...LOT...MKX...DVN...ARX...DMX...

   LAT...LON   41729328 41889371 42309395 42769393 43079356 43249277
               43389085 43338912 43088858 42328852 41908884 41708959
               41649094 41679239 41729328