Mesoscale Discussion 1480
   NWS Storm Prediction Center Norman OK
   1128 PM CDT Thu Aug 13 2020

   Areas affected...Southeast Montana/northwest South Dakota/southern
   North Dakota

   Concerning...Severe potential...Watch possible 

   Valid 140428Z - 140630Z

   Probability of Watch Issuance...60 percent

   SUMMARY...The potential for severe thunderstorms capable of
   hail/wind is expected to increase late this evening into the
   overnight from southeast Montana into northwest South Dakota and
   southern North Dakota. A Severe Thunderstorm Watch may be needed for
   at least parts of the region.

   DISCUSSION...A mid/upper-level trough will continue to amplify and
   spread eastward over the northern High Plains late tonight,
   accompanied by a strengthening deep-layer wind field highlighted by
   50+ knot west-southwesterly mid-level winds. Storms have already
   begun to increase across southeast Montana with aid of appreciable
   forcing for ascent related to the advancing trough. While moisture
   is limited within the post-frontal environment across southeast
   Montana and the far western Dakotas, it is expected that storms will
   gradually intensify and organize as they encounter somewhat richer
   moisture and a moderate reservoir of instability with eastward
   extent across southern North Dakota/northern South Dakota.

   Isolated severe hail is the most probable risk initially, although
   steep lapse rates/semi-dry sub-cloud layers should be conducive to
   cold pool development and an increase in severe-caliber wind gust
   potential with linear segments/bows overnight, particularly across
   southern North Dakota. Developmental trends are being monitored for
   a possible Severe Thunderstorm Watch.

   ..Guyer.. 08/14/2020

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

   ATTN...WFO...ABR...BIS...UNR...BYZ...

   LAT...LON   46470514 46750290 47280033 46339981 45860090 45520511
               46470514