SPC AC 211956

   Day 1 Convective Outlook  
   NWS Storm Prediction Center Norman OK
   0256 PM CDT Tue Jun 21 2022

   Valid 212000Z - 221200Z

   ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS NORTHEAST KANSAS
   TO SOUTHEAST IOWA...

   ...SUMMARY...
   Isolated to scattered damaging winds and isolated large hail will be
   possible from northeast Kansas to southeast Iowa between about 5 to
   10 PM CDT.

   A broad cu field has developed from northwest Missouri into
   north-central Wisconsin along and ahead of a cold front in the
   region. Thus far, only occasional robust convective attempts have
   occurred, and failed across Wisconsin. Expect this trend to continue
   given the veered surface flow ahead of the cold front across the
   region. However, if any storms can develop, the environment is
   favorable for strong, rotating updrafts with MLCAPE around 2500 J/kg
   and ~35 knots of effective shear per SPC mesoanalysis. 

   Farther southwest, more northerly post-frontal winds have resulted
   in stronger convergence which should lead to more convective
   coverage than farther north. Between 1930-20Z, a more confined line
   of cumulus has developed across northeast Kansas per visible
   satellite. This likely represents the frontal location and should
   provide the focus for thunderstorm development this evening. Latest
   HRRR solutions indicate thunderstorm development between 22-23Z
   which seems appropriate based on satellite trends. Multicell
   clusters remain the expected storm mode with a primary threat for
   damaging winds.

   ..Bentley.. 06/21/2022

   .PREV DISCUSSION... /ISSUED 1127 AM CDT Tue Jun 21 2022/

   ...Central KS to IA/IL/WI border area...
   A corridor of boundary-layer dewpoints in the upper 60s to lower 70s
   will be maintained immediately ahead of a cold front, trailing off
   with western extent into KS where it intersects the dryline. Large
   buoyancy with MLCAPE from 2000-3500 J/kg will likely develop amid
   hot surface temperatures warming into the mid to upper 90s from
   northeast KS northeastward, with lower buoyancy but a deeper-mixed
   boundary layer into central KS. While the entire region will remain
   well removed from the direct influence of a shortwave trough over
   southern Manitoba moving into northwest Ontario, an MCV over NM will
   drift towards the south-central High Plains. A belt of confluent
   mid-level southerlies ahead of this feature transitioning to modest
   west-southwesterlies with northeast extent on the periphery of
   stronger flow over the north-central states may provide sufficient
   deep-layer shear for multicell clustering with convection that
   develops along the front. This appears most probable from northeast
   KS into southeast IA where steep low-level lapse rates and DCAPE to
   near 1500 J/kg would favor isolated to perhaps scattered downbursts
   producing 50-70 mph wind gusts during the early evening. Isolated
   quarter to golf ball-sized hail should be a secondary threat in
   terms of coverage and most likely with initial robust updrafts.

   ...Eastern Upper/northern Lower MI into eastern WI...
   Low-level convergence is consistently forecast to remain weak along
   this portion of the cold front pushing east across the region, with
   largely veered winds. As such, signals for convective development
   are sparse across morning guidance. Nevertheless, stronger
   deep-layer flow along with a plume of steep mid-level lapse rates
   will support a conditionally favorable setup for isolated severe
   hail and wind.

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