Mesoscale Discussion 0922
   NWS Storm Prediction Center Norman OK
   0655 PM CDT Tue Jun 16 2020

   Areas affected...Western and Central North Dakota

   Concerning...Severe potential...Watch possible 

   Valid 162355Z - 170230Z

   Probability of Watch Issuance...40 percent

   SUMMARY...An isolated severe threat is expected to develop across
   parts of western and central North Dakota over the next couple of
   hours. Isolated large hail and wind damage will be the primary
   threats. Weather watch issuance will need to be considered as cells
   develop and increase in coverage.

   DISCUSSION...The latest surface analysis shows a 999 mb low in
   southwest North Dakota. A cold front is present from just to the
   west of the surface low extending southwestward into northeast
   Wyoming. Convection initiated in far southwest North Dakota near the
   front over the last hour but has failed to become established. A
   moist airmass exists to the east of the front across much of North
   Dakota where surface dewpoints are as high as the lower to mid 60s F
   in the southern part of the state. The convection is also located
   along a band of large-scale ascent associated with a shortwave
   trough across the northern High Plains, evident on water vapor
   imagery.  As the cap weakens a bit more and large-scale ascent
   spreads across west-central North Dakota, thunderstorm development
   will be likely and cells should increase in coverage. The
   thermodynamic environment is currently moderately unstable in
   west-central North Dakota with the RAP showing MLCAPE in the 1500 to
   3000 J/kg range. In addition, the Bismarck WSR-88D VWP has 35 kt of
   0-6 km shear with veering winds with height in the lowest 2 km. The
   instability and wind shear profiles will be favorable for strong to
   severe thunderstorm development this evening and supercells will be
   possible. Isolated large hail and wind damage will be the primary
   threats.

   At this time, some uncertainty exists concerning the timing of
   thunderstorm development across the northern Plains. The current
   thinking is that convection will continue to percolate in
   southwestern North Dakota for another hour or so. Then, convection
   should become vigorous enough for thunderstorm development, mainly
   after 0130Z. Thunderstorms are forecast to expand northward across
   west-central North Dakota after that and should obtain an isolated
   severe threat.

   ..Broyles/Grams.. 06/16/2020

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

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

   LAT...LON   48880190 48050270 47380306 46070323 45910212 46200129
               47170063 48660004 49000102 48880190