Mesoscale Discussion 0961
   NWS Storm Prediction Center Norman OK
   0659 PM CDT Sun Jun 21 2020

   Areas affected...Parts of central into eastern Nebraska...western
   Iowa...and extreme southeast South Dakota

   Concerning...Severe Thunderstorm Watch 291...

   Valid 212359Z - 220200Z

   The severe weather threat for Severe Thunderstorm Watch 291
   continues.

   SUMMARY...The severe threat continues across Severe Thunderstorm
   Watch 0291, with a recent uptick in convective coverage/intensity
   noted. Large hail appears to be the primary threat. A couple of
   severe gusts will also be possible with the stronger, longer lasting
   storms.

   DISCUSSION...Relatively robust convective initiation has recently
   been noted across portions of central NE, with convection struggling
   to intensify farther northeast near the NE/SD/IA border area. The
   newer storms across central NE will continue to develop along the
   I-80 corridor for at least the next few hours. 7.5 C/km mid-level
   lapse rates (per latest Mesoanalysis) suggest that the most robust
   updrafts will support severe hail potential, with KUEX
   dual-polarimetric and mosaic MRMS data suggesting occasional severe
   hail occurring. A few severe gusts also cannot be ruled out. 

   However, despite up to 2000 J/kg MLCAPE present, low-level shear
   remains relatively poor. With modest (i.e. 35 knot) effective bulk
   shear in place, individual storms (including transient supercells)
   may struggle to sustain themselves longer than 2-3 hours, as noted
   by the last few HRRR deterministic and Warn-on-Forecast ensemble
   forecasts. After sunset, nocturnal cooling is expected to encourage
   gradual weakening of any storms that remain.

   ..Squitieri/Thompson.. 06/21/2020

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

   ATTN...WFO...DMX...FSD...OAX...GID...LBF...GLD...

   LAT...LON   39840020 41509995 42859783 43699524 42469488 41459536
               40619638 40079733 39840020