Mesoscale Discussion 0817
   NWS Storm Prediction Center Norman OK
   0225 PM CDT Thu Jun 04 2020

   Areas affected...The Montana/Wyoming/South Dakota tri-state region
   into north-central Nebraska

   Concerning...Severe potential...Watch likely 

   Valid 041925Z - 042100Z

   Probability of Watch Issuance...95 percent

   SUMMARY...Additional thunderstorm development is expected in the
   coming hours across the MT/WY/SD tri-state region. These storms will
   be capable of strong wind and severe hail as they move towards
   north-central Nebraska through the evening hours.

   DISCUSSION...Recent visible imagery shows signs of increasing
   vertical development within cumulus fields that are developing off
   the higher terrain of the Black Hills and along the MT/WY border.
   Isolated to scattered thunderstorms are expected to develop within
   this region and propagate to the east/southeast towards
   south-central SD and north-central NE into the evening hours. 40 to
   55 knots of effective bulk shear within this region should
   compensate for modest, but sufficient, MLCAPE values across much of
   southwest SD (500-1000 J/kg). Nearly straight hodographs, noted in
   recent KBIS VWP data as well as RAP forecast soundings, will favor
   organized splitting storms that will be capable of producing both
   severe hail and wind. A tornado or two can not be ruled out across
   southwest to south central SD during the late afternoon/evening
   hours where 100-150 m2/s2 ESRH is noted in recent RAP mesoanalyses
   and upper 50s to low 60s dewpoints have been observed at the
   surface.

   ..Moore/Grams.. 06/04/2020

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

   ATTN...WFO...FSD...ABR...BIS...LBF...UNR...BYZ...

   LAT...LON   45830578 46240376 45400160 44409953 43709862 42759879
               42279937 42120008 42610131 42890234 43320348 44030546
               44820599 45830578