Storm Prediction Center Mesoscale Discussion 760

   Mesoscale Discussion 0760
   NWS Storm Prediction Center Norman OK
   0545 PM CDT Sun May 17 2026

   Areas affected...portions of northern Iowa into southern Minnesota

   Concerning...Severe potential...Tornado Watch likely 

   Valid 172245Z - 172345Z

   Probability of Watch Issuance...80 percent

   SUMMARY...The severe threat will increase over the next few hours.
   Severe wind and hail are likely, with tornadoes also possible. A
   Tornado Watch may be needed soon to address the impending threat.

   DISCUSSION...A bowing QLCS is traversing the far western IA/MN
   border, with a recent history of marginal severe hail/wind occurring
   with an embedded supercell structure. This QLCS is tracking eastward
   toward the axis of a 30-40 kt low-level jet, where low-level shear
   is increasing (i.e. 200+ m2/s2 effective SRH per 22Z mesoanalysis).
   Furthermore, 8+ C/km mid-level lapse rates are overspreading upper
   60s to near 70 F surface dewpoints in the warm sector ahead of the
   QLCS, yielding up to 3000 J/kg MLCAPE. With 40+ kts of effective
   bulk shear also in place, potential exists for the QLCS to
   strengthen, with a corresponding increase in severe wind and hail
   potential. Line-embedded tornadoes may also occur, especially with
   portions of the QLCS that interact with an approaching warm front. A
   Tornado Watch may need to be issued in the next couple of hours.

   ..Squitieri/Smith.. 05/17/2026

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

   ATTN...WFO...ARX...MPX...DMX...FSD...

   LAT...LON   42589521 44019511 44269487 44329424 44209347 43859281
               43459256 42919281 42629326 42429418 42469470 42589521 

   MOST PROBABLE PEAK TORNADO INTENSITY...100-125 MPH
   MOST PROBABLE PEAK WIND GUST...65-80 MPH
   MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN