Mesoscale Discussion 0935
   NWS Storm Prediction Center Norman OK
   0630 PM CDT Thu Jun 18 2020

   Areas affected...northeastern Kansas and southeastern Nebraska into
   parts of Iowa and northwestern Missouri

   Concerning...Severe potential...Watch possible 

   Valid 182330Z - 190130Z

   Probability of Watch Issuance...40 percent

   SUMMARY...A few occasionally stronger storms within the discussion
   area will be capable of producing large hail and locally
   gusty/damaging winds.  Risk may remain temporally and areally
   limited so as to preclude the need for WW issuance, but we will
   continue to monitor convective evolution.

   DISCUSSION...Latest radar loop shows an active zone of convection
   from southern Minnesota south-southwestward to
   north-central/northeastern Kansas, along and ahead of the slowly
   advancing surface front.

   The environment ahead of the front is characterized by low to mid
   60s surface dewpoints, which combined with daytime heating is
   yielding mixed-layer CAPE on the order of 1500 to 2000 J/kg within
   the discussion area.  This is fueling persistent storm development
   -- particularly from southeast Nebraska southwestward to
   Lincoln/Mitchell Counties in Kansas.

   Despite ample CAPE for robust updrafts, the deep-layer wind remains
   marginal for a more substantial severe event.  Though ample veering
   with height -- from southerly to westerly through mid levels -- is
   yielding enough shear for multicell organization and some
   weak/transient updraft rotation, mid-level flow of 20 to 25 kt over
   Nebraska/Iowa, and weakening with southward extent, is observed. 
   This suggests that the overall degree of risk will remain limited --
   with maximum hail size in the 1" to 1.75" range, and severe-caliber
   wind gusts very local and brief.  While the evolution of a low-level
   jet across this region over the next few hours will likely sustain
   convection, the most likely scenario appears that a
   southeastward-moving outflow will evolve, with storm redevelopment
   favored on the cool side of the outflow.  The anafrontal/elevated
   nature of this convection -- particularly as the boundary layer
   cools -- likely precludes appreciable increase in wind risk, with
   marginal hail and locally heavy rainfall likely to be the most
   dominant risks after dark.

   ..Goss/Thompson.. 06/18/2020

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

   ATTN...WFO...DMX...EAX...OAX...TOP...ICT...GID...

   LAT...LON   38499809 39359810 40659669 41739585 41939505 42059376
               41669265 40439326 39039491 38459662 38499809