Storm Prediction Center Mesoscale Discussion 440

   Mesoscale Discussion 0440
   NWS Storm Prediction Center Norman OK
   0716 PM CDT Tue Apr 27 2021

   Areas affected...Northeast Colorado...Southwest Nebraska...and
   Northwest Kansas

   Concerning...Severe Thunderstorm Watch 112...114...

   Valid 280016Z - 280215Z

   The severe weather threat for Severe Thunderstorm Watch 112, 114
   continues.

   SUMMARY...The threat for severe wind and hail will continue across
   far northeast Colorado and into adjacent areas of southwest Nebraska
   and northwest Kansas through the evening hours.

   DISCUSSION...Satellite and radar trends over the past hour have
   shown gradual upscale growth from discrete/semi-discrete storms into
   a more linear storm mode due to destructive storm interactions and
   conglomeration of cold pools. Velocity data from KGLD supports this
   idea with a more unified outflow boundary associated with the main
   convective cluster becoming apparent. Satellite imagery continues to
   show robust updraft pulses within the evolving line, and flash rates
   have maintained intensity as storms move into a more favorable
   thermodynamic environment. The continued organization of the cold
   pool within a strongly sheared environment (50-60 knots of effective
   bulk shear and 40 knots of 0-3 km shear) will support the potential
   for an organized wind threat, and possibly a bowing segment, as
   storms continue to move to the east/northeast through 04 UTC. While
   damaging winds will become the main threat, stronger updraft pulses
   will be capable of producing severe hail within the line. A brief
   tornado remains possible given increasing low-level helicity and
   strong low-level bulk shear (per RAP mesoanalysis and the KGLD VWP),
   but increasing SBCIN and a linear storm mode cast some uncertainty
   into the tornado potential heading into the late evening hours.

   ..Moore.. 04/28/2021

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

   ATTN...WFO...GID...LBF...GLD...BOU...

   LAT...LON   39000273 39730290 40370287 40940181 41290089 41150040
               40839993 40259970 39590003 39260069 38990172 39000273