Mesoscale Discussion 1621
   NWS Storm Prediction Center Norman OK
   0628 PM CDT Fri Aug 27 2021

   Areas affected...far eastern NE...west-central IA

   Concerning...Severe potential...Watch possible 

   Valid 272328Z - 280100Z

   Probability of Watch Issuance...40 percent

   SUMMARY...Isolated large hail and severe gusts are possible with the
   more intense thunderstorms this evening.  Overall storm coverage is
   still uncertain (i.e., isolated) and the lower storm coverage may
   preclude a severe thunderstorm watch being issued, although the
   stronger storms will potentially be capable of severe weather given
   the favorable environment.

   DISCUSSION...Visible-satellite imagery shows developing convection
   over far eastern NE into west-central IA on the trailing portion of
   a mid-level shortwave trough migrating east-northeastward over the
   Upper Midwest.  Surface conditions are hot and humid with
   temperatures in the lower 90s with lower 70s dewpoints.  The RAP
   forecast sounding for Omaha, NE shows a good depiction of the
   surface conditions and it indicates around 3300 J/kg MLCAPE. 
   Although flow is relatively modest in the lowest 9 km per KOAX 88D
   VAD data (sub 30 kt), 25-30 kt effective shear is indicated and
   would in turn support organized storm structures this evening.  The
   main threats with the stronger storms would be a hail/wind threat.

   ..Smith/Bunting.. 08/27/2021

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

   ATTN...WFO...DMX...FSD...OAX...

   LAT...LON   41319663 42129588 42589525 42659446 42359396 41819414
               41149559 40929619 41319663