Mesoscale Discussion 1480
   NWS Storm Prediction Center Norman OK
   0320 PM CDT Mon Jul 15 2019

   Areas affected...portions of eastern Wyoming...southwest South
   Dakota...western Nebraska

   Concerning...Severe potential...Severe Thunderstorm Watch likely 

   Valid 152020Z - 152245Z

   Probability of Watch Issuance...80 percent

   SUMMARY...Storm coverage will increase this afternoon/evening across
   portions of the central/northern High Plains. Severe hail and wind
   are the main threats, and a severe thunderstorm watch issuance is
   likely.

   DISCUSSION...An upper-level disturbance is moving over western South
   Dakota and northwest Nebraska while another disturbance is moving
   over western Wyoming. These disturbances are helping to provide
   forcing for ascent and aiding convective initiation along with
   insolation, terrain, and surface boundaries. The best buoyancy is
   located across western Nebraska and south/east of the Black Hills in
   South Dakota where surface dewpoints are in the 50s to upper 60s F
   and temperatures in the 80s to low 90s F. Storms will move eastward
   off the higher terrain in Wyoming and onto the High Plains this
   afternoon/evening. Additional development is also possible along the
   cold front in South Dakota and along surface convergence ahead of
   this (possibly a pre-frontal trough). 

   Supercells are possible, at least initially, given the 40-50 knots
   of effective bulk shear across the area, but upscale growth and a
   mixed storm mode are likely this evening with the upper-level
   forcing. Storms will likely intensify with time as they move into
   better instability. Large hail and damaging wind gusts are the main
   threats and a severe thunderstorm watch issuance is likely for a
   large portion of the MCD.

   ..Nauslar/Dial.. 07/15/2019

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

   ATTN...WFO...LBF...UNR...CYS...BYZ...RIW...

   LAT...LON   41730110 41040225 41040328 41250421 41610519 42300602
               42940648 43480655 45050560 45510536 45620464 45430389
               44300234 43570164 43320087 42940012 42739983 42549975
               42270001 42060043 41730110