Storm Prediction Center Mesoscale Discussion 438

   Mesoscale Discussion 0438
   NWS Storm Prediction Center Norman OK
   0524 PM CDT Tue Apr 27 2021

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

   Concerning...Severe Thunderstorm Watch 112...

   Valid 272224Z - 280030Z

   The severe weather threat for Severe Thunderstorm Watch 112
   continues.

   SUMMARY...A severe hail and wind risk will continue for the next few
   hours and may extend into portions of northwest KS and southwest NE.
   While hail/wind will be the primary threat, a tornado or two will
   remain possible in the near term.

   DISCUSSION...Convection continues to mature across northeast CO as
   storms slowly move eastward towards the KS/NE border. Clearing skies
   and richer boundary-layer moisture across northwest KS have allowed
   instability to increase across this region to nearly 1500 J/kg
   SBCAPE, which may support an increase in intensity of the ongoing
   convection (especially within the Limon, CO to northwest KS
   corridor). East/northeasterly low-level winds are supporting
   elongated hodographs and 50-60 knots of effective bulk shear across
   this region, which should further support organized convection.
   Additionally, this backed flow along and north of a warm
   front/dryline boundary is supporting 100-200 m2/s2 of effective SRH
   (around 150 m2s2 0-1 km SRH per the KGLD VWP). This has been
   sufficient for a couple of brief tornadoes across the CO Plains.
   This will continue to support a tornado threat with any discrete
   convection in the near term before deeper boundary-layer mixing
   reduces low-level directional shear. Discrete storms are expected to
   gradually grow upscale via storm interactions as they move closer to
   the NE/KS border, but given the relatively limited spatial extent of
   favorable instability (possibly confined to east CO/northwest KS per
   satellite trends), the coverage of the severe threat is somewhat
   uncertain after 01 UTC. Trends will be monitored and a new watch may
   be needed in the coming hours.

   ..Moore.. 04/27/2021

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

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

   LAT...LON   38500339 39070372 39970401 40590316 41030182 41110095
               40820023 40329969 39599949 39199975 39180096 38760254
               38500339