Storm Prediction Center Mesoscale Discussion 1429

   Mesoscale Discussion 1429
   NWS Storm Prediction Center Norman OK
   0611 PM CDT Wed Jul 01 2026

   Areas affected...Northeast NE...northern IA...southern MN...western
   WI...and far southeast SD

   Concerning...Severe potential...Watch likely 

   Valid 012311Z - 020115Z

   Probability of Watch Issuance...80 percent

   SUMMARY...The area is being monitored for thunderstorm development
   and an increasing all-hazards severe risk. While timing/evolution of
   the severe risk remains uncertain, current thinking is that a watch
   will be needed.

   DISCUSSION...The latest visible satellite imagery indicates a
   ENE/WSW-oriented band of gradually deepening boundary-layer cumulus
   along a subtle surface boundary/confluence zone extending from
   southern MN into northwest IA and vicinity. Over the next couple
   hours, a strengthening southerly LLJ and related isentropic lift
   should reduce remaining inhibition (sampled by the OAX 18Z sounding)
   and promote widely scattered thunderstorm development along/near the
   boundary. A warm/moist PBL (lower/middle 70s dewpoints) beneath
   steep lapse rates is yielding strong surface-based buoyancy, which
   combined with around 40 kt of effective shear, will favor storm
   organization/intensification. Given the increasing warm advection
   and boundary-parallel deep-layer shear, a mixed mode of supercells
   and organized clusters will pose a risk for severe/damaging wind
   gusts, large hail, and a couple tornadoes (given increasing
   clockwise-curved low-level hodographs). 

   While the subtle forcing for ascent casts uncertainty on overall
   convective timing/evolution, current thinking is that a watch will
   be needed for parts of the area.

   ..Weinman/Thompson.. 07/01/2026

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

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

   LAT...LON   44469322 44659194 44589123 44389095 43769060 43349083
               42599326 42149444 41699613 41769697 42019768 42649767
               43029706 44469322 

   MOST PROBABLE PEAK TORNADO INTENSITY...85-110 MPH
   MOST PROBABLE PEAK WIND GUST...65-80 MPH
   MOST PROBABLE PEAK HAIL SIZE...1.50-2.50 IN