Mesoscale Discussion 0615
   NWS Storm Prediction Center Norman OK
   0602 PM CDT Fri Jun 01 2018

   Areas affected...Portions of western/central ND

   Concerning...Tornado Watch 146...

   Valid 012302Z - 020030Z

   The severe weather threat for Tornado Watch 146 continues.

   SUMMARY...The threat for a few tornadoes, large hail, and damaging
   winds continues across WW 146.

   DISCUSSION...RAP mesoanalysis shows a surface low over central SD,
   with surface troughing extending northward from this low across
   south-central into western ND. A band of thunderstorms has recently
   formed along the surface trough in western/south-central ND. A
   narrow corridor of surface heating has occurred ahead of this
   convection mainly across central ND, and a reservoir of relatively
   better low-level moisture is also present over this area.
   Southeasterly low-level winds quickly veering and strengthening with
   height to southwesterly at mid levels are resulting in effective
   bulk shear values of 40-50 kt. Supercell structures have been noted
   with the line of thunderstorms, and given the sufficient instability
   and strong shear, large hail and damaging winds will continue to be
   a threat. Pronounced low-level hodograph curvature noted in both the
   KBIS and KMBX VWPs is supporting effective SRH values of 350-500+
   m2/s2. Tornadoes will be possible with any sustained, rotating
   updraft embedded within the line given the magnitude of the
   low-level shear and vertical vorticity present along the boundary.
   In the short-term, the best tornado potential would seem to be
   focused along and just northeast of the line. Continued
   consolidation of the line would suggest an eventual transition to a
   greater wind threat through the evening hours.

   ..Gleason.. 06/01/2018

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

   ATTN...WFO...BIS...

   LAT...LON   45990193 46600202 47480288 48230400 48940398 48950021
               47839989 45969901 45990193