Storm Prediction Center Mesoscale Discussion 1390

   Mesoscale Discussion 1390
   NWS Storm Prediction Center Norman OK
   1008 PM CDT Fri Jun 20 2025

   Areas affected...Southeast North Dakota

   Concerning...Tornado Watch 448...

   Valid 210308Z - 210445Z

   The severe weather threat for Tornado Watch 448 continues.

   SUMMARY...A pair of long-lived supercells will reside within a
   favorable tornado environment for at least the next 1-2 hours before
   merging with an approaching MCS.

   DISCUSSION...Over the past two hours, a pair of long-lived
   supercells (one of which has a history of producing 2-3 inch hail
   and multiple tornadoes) have meandered slowly east/southeastward
   along the I-94 corridor and are moving towards a regional buoyancy
   maximum (MLCAPE estimated to be around 4000 J/kg) driven by rich
   low-level moisture (dewpoints in the low 70s). This rich moisture
   will help modulate the influence of nocturnal low-level
   stabilization and help maintain very buoyant near-surface parcels.
   Additionally, the approach of a mid-level perturbation from the west
   is inducing a low-level mass response that is resulting in a
   strengthening of the low-level jet - and consequently increasing
   low-level SRH - as sampled by recent KABR VWP observations. These
   trends suggest that the downstream environment may become
   increasingly supportive of tornadic supercells in the short term.
   Given this environment and velocity imagery from KMVX, it is
   estimated that strong (EF-2 to EF-3) tornadoes will remain possible.
   With time, these supercells will eventually merge with the
   approaching MCS from the west. Based on recent storm tracks, this
   appears most probable during the 04-05 UTC time frame, at which
   point the primary threat will become widespread severe winds.

   ..Moore.. 06/21/2025

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

   ATTN...WFO...FGF...BIS...

   LAT...LON   46269797 46399824 46629828 47089808 47249737 47259699
               47159681 46799671 46579670 46429676 46239687 46159699
               46099718 46269797 

   MOST PROBABLE PEAK TORNADO INTENSITY...120-150 MPH
   MOST PROBABLE PEAK WIND GUST...75-90 MPH
   MOST PROBABLE PEAK HAIL SIZE...2.00-3.50 IN