Mesoscale Discussion 1422
   NWS Storm Prediction Center Norman OK
   0137 PM CDT Tue Jul 09 2019

   Areas affected...Northeast Wyoming...Southwest South
   Dakota...Northwest Nebraska

   Concerning...Severe potential...Watch possible 

   Valid 091837Z - 092100Z

   Probability of Watch Issuance...60 percent

   SUMMARY...A severe threat is expected to develop this afternoon
   across parts of the northern High Plains. Wind damage and isolated
   large hail will be possible with the stronger thunderstorms. Weather
   watch issuance may be needed across the region.

   DISCUSSION...The latest surface analysis shows a post-frontal
   airmass over the northern High Plains with northwest low-level flow.
   Surface dewpoints are generally in the 50s F from northeast Wyoming
   into southwest South Dakota. Weak instability has develops across
   the area over the last few hours with the RAP estimating MLCAPE
   values in the 500 to 1000 J/kg range. This combined with large-scale
   ascent associated with a shortwave trough over the northern Rockies
   will provide support for continued convective development this
   afternoon. In addition to increasing instability, the Rapid City
   WSR-88D VWP shows 0-6 km shear around 40 kt. This combined with
   steep mid-level lapse rates will be sufficient for a few severe
   storms with isolated large hail potential. Damaging wind gusts will
   also be possible especially if a line of storms can organize late
   this afternoon.

   ..Broyles/Grams.. 07/09/2019

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

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

   LAT...LON   45020418 44920647 44660694 44060703 43290668 42630590
               42330486 42260404 42240311 42320195 42730130 43740087
               44170090 44660115 44940221 45020418