Storm Prediction Center Mesoscale Discussion 584

   Mesoscale Discussion 0584
   NWS Storm Prediction Center Norman OK
   1258 AM CDT Mon Apr 28 2025

   Areas affected...Southeastern South Dakota...Northern Nebraska

   Concerning...Severe potential...Watch likely 

   Valid 280558Z - 280730Z

   Probability of Watch Issuance...95 percent

   SUMMARY...A severe threat is expected to move east-northeastward
   across southeastern South Dakota and far northern Nebraska over the
   next few hours. Large hail, wind damage and a tornado threat are
   expected. Weather watch issuance will be needed to the east of the
   ongoing watch.

   DISCUSSION...The latest mosaic radar imagery shows a severe line
   segment from far northern Nebraska into far southern South Dakota.
   This line will move east-northeastward along a gradient of moderate
   instability, where the RAP has MLCAPE in the 1500 to 2500 J/g range.
   In addition to the instability, warm advection and large-scale
   ascent associated with a shortwave trough will support the line over
   the next few hours. The latest VWP in northern Nebraska has 0-6 km
   shear of 40 to 45 knots, and a gradually veering wind with height in
   the low to mid-levels, suggesting that a severe threat will
   continue. Large hail and severe gusts will be likely within the
   stronger components of the line. Strong low-level shear will also
   support a tornado threat with embedded rotating cells within the
   line.

   ..Broyles/Mosier.. 04/28/2025

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

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

   LAT...LON   42990067 42580055 42219999 42289906 42539767 42869694
               43279665 43899664 44299693 44569742 44629800 44289947
               43980035 43480067 42990067 

   MOST PROBABLE PEAK TORNADO INTENSITY...100-130 MPH
   MOST PROBABLE PEAK WIND GUST...65-80 MPH
   MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN