Storm Prediction Center Mesoscale Discussion 2026

   Mesoscale Discussion 2026
   NWS Storm Prediction Center Norman OK
   0941 PM CDT Wed Aug 28 2024

   Areas affected...parts of north central South Dakota and south
   central North Dakota

   Concerning...Tornado Watch 661...

   Valid 290241Z - 290445Z

   The severe weather threat for Tornado Watch 661 continues.

   SUMMARY...Thunderstorm development, in general, is beginning to
   weaken, with the risk for tornadoes likely to become increasingly
   negligible through 10-11 PM CDT.  Some risk for severe hail and,
   perhaps, localized strong wind gusts may persist into the overnight
   hours across parts of the central and eastern Dakotas.  However, a
   new severe weather watch is not currently anticipated.

   DISCUSSION...Ongoing convection appears to be undergoing notable
   weakening trends, including the the isolated supercell just south of
   the state border vicinity, across eastern Campbell county South
   Dakota.  This has occurred as the loss of daytime heating has
   resulted in increasing inhibition for the seasonably moist boundary
   parcels near the surface trough across the central Dakotas. 
   However, forcing associated with strong low-level warm advection may
   maintain at least a severe hail threat with the Campbell county
   storm as it accelerates north-northeastward, and becomes
   increasingly rooted above the boundary layer during the next hour or
   two.

   Strongest potential instability remains focused near a weak surface
   low, centered within the surface trough to the north-northwest of
   Pierre SD.  However, as the slow moving upstream low, now centered
   over southern Saskatchewan just to the north of the international
   border, continues east-northeastward, models suggest that warming
   elevated mixed-layer air will gradually advect across the central
   North and South Dakota state border area through 04-05Z.  As this
   occurs, the potential for renewed thunderstorm development rooted
   within the unstable boundary layer is expected to diminish.

   ..Kerr.. 08/29/2024

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

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

   LAT...LON   45960044 47149937 46599839 45019952 45030058 45960044