Mesoscale Discussion 1453
   NWS Storm Prediction Center Norman OK
   0621 PM CDT Thu Jun 27 2024

   Areas affected...portions of central North Dakota into central South
   Dakota

   Concerning...Severe potential...Severe Thunderstorm Watch likely 

   Valid 272321Z - 280045Z

   Probability of Watch Issuance...95 percent

   SUMMARY...The severe threat is increasing across portions of central
   ND into central SD as strong to potentially severe storms approach
   from the west. Severe gusts are the main threat, though some
   instances of severe hail and perhaps a tornado also may occur. A
   Severe Thunderstorm Watch issuance will be needed within the hour.

   DISCUSSION...Multicells and discrete supercells are moving across
   western SD/ND and are approaching the eastern bounds of Severe
   Thunderstorm Watch 475 and Tornado Watch 476. Meanwhile, a mature
   MCS continues to rapidly propagate eastward into ND from MT, and is
   poised to reach central ND in the next few hours. As these storms
   merge and approach central SD/ND, severe gusts will become likely as
   the storms move into a strongly unstable airmass (characterized by
   up to 3500 J/kg MLCAPE per 23Z mesoanalysis). Furthermore, the
   strengthening of the southerly LLJ (to 40+ kts), beneath increasing
   westerly 500 mb flow with the ejection of a mid-level vort max, will
   support effective bulk shear values well over 50 kts. Regional VADs
   and short-term RUC forecasts show enlarged and curved low-level
   hodographs with modest mid-level elongation. As such, any storms
   that remain surface based as they move into the central Dakotas
   should be accompanied by a severe threat. The eastward moving MCS
   should produce at least some severe wind, which is expected to be
   the predominant severe hazard. However, embedded mesovortices may be
   accompanied by an isolated tornado threat.

   A Severe Thunderstorm Watch will be issued within the hour to
   address the impending severe threat.

   ..Squitieri/Smith.. 06/27/2024

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

   ATTN...WFO...FGF...ABR...BIS...UNR...

   LAT...LON   45990189 48440204 48960169 48660054 47669954 46719939
               45259904 44219928 43919977 43950084 45990189