Storm Prediction Center Mesoscale Discussion 1481

   Mesoscale Discussion 1481
   NWS Storm Prediction Center Norman OK
   0918 PM CDT Fri Jun 27 2025

   Areas affected...portions of central South Dakota

   Concerning...Severe Thunderstorm Watch 469...

   Valid 280218Z - 280345Z

   The severe weather threat for Severe Thunderstorm Watch 469
   continues.

   SUMMARY...Damaging winds appear likely to continue this evening as a
   couple of severe storm clusters spread eastward across WW469. A
   local expansion may be needed as storms approach the eastern edge of
   the watch.

   DISCUSSION...As of 0210 UTC, regional radar imagery showed two
   clusters of severe thunderstorms ongoing within WW469 across SD. The
   northern most cluster (across parts of Carson, Ziebach and Dewey
   Counties) has shown steady intensification over the last hour as it
   has moved into large buoyancy (MLCAPE ~4000 J/kg). This
   intensification trend should continue with the environment
   downstream still very unstable and supportive of severe storms. As
   low-level warm advection increases with the arrival of the low-level
   jet, continual upscale growth is expected. Therefore, damaging gusts
   are the most likely hazard.

   Farther south, initial supercells have gradually coalesced into a
   broader cluster roughly along I-90. An increase in forward speed and
   recent wind gust to 71 mph suggests a stronger cold pool is becoming
   established. Similar to the northern cluster, a very unstable
   environment remains in place, supportive of organized deep
   convection. This should support a continued threat for damaging
   winds and some hail as this storm cluster propagates east/southeast
   this evening.

   ..Lyons.. 06/28/2025

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

   ATTN...WFO...FSD...OAX...ABR...LBF...UNR...

   LAT...LON   45909899 45889853 44639754 44539749 43749708 42949718
               42849769 42819798 43139954 44110087 44770136 45820115
               45909899 

   MOST PROBABLE PEAK TORNADO INTENSITY...85-115 MPH
   MOST PROBABLE PEAK WIND GUST...65-80 MPH
   MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN