Storm Prediction Center Mesoscale Discussion 864

   Mesoscale Discussion 0864
   NWS Storm Prediction Center Norman OK
   0539 PM CDT Sun May 18 2025

   Areas affected...Southern Nebraska...North-central Kansas

   Concerning...Severe potential...Watch likely 

   Valid 182239Z - 190115Z

   Probability of Watch Issuance...80 percent

   SUMMARY...A severe threat will likely continue across north-central
   Kansas, and expected to develop across parts of southern Nebraska.
   Supercells with large to very large hail, wind damage and an
   isolated tornado threat will be possible. Weather watch issuance
   appears likely.

   DISCUSSION...Over the last hour, convection has increased in
   coverage across north-central Kansas. The storms are located along
   the eastern edge of a moderately unstable airmass, where surface
   dewpoints are in the lower 60s F. The storms appears to be related
   to a band of large-scale ascent that is moving northeastward across
   the central Plains, evident on water vapor imagery. The North-Platte
   20Z sounding shows a cap in place, and RAP forecast soundings
   suggest the cap extends further to the southeast into north-central
   Kansas. For this reason, the ongoing convection appears to be
   elevated. Effective shear of 50 to 60 knots and 700-500 mb lapse
   rates near 8 C/km will be favorable for supercells with large hail.
   Hailstones greater than 2 inches in diameter will be possible. In
   addition, an isolated wind-damage/tornado threat will also be
   possible. Although this potential will increase later this evening
   as a second round of storms move into the area.

   ..Broyles.. 05/18/2025

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

   ATTN...WFO...OAX...TOP...ICT...GID...LBF...DDC...GLD...

   LAT...LON   38319798 38129738 38269694 38499664 39029644 39599675
               40239760 41069890 41139952 40799997 40289994 39569951
               38829873 38319798 

   MOST PROBABLE PEAK TORNADO INTENSITY...100-130 MPH
   MOST PROBABLE PEAK WIND GUST...55-70 MPH
   MOST PROBABLE PEAK HAIL SIZE...2.00-3.50 IN