Mesoscale Discussion 1513
   NWS Storm Prediction Center Norman OK
   1043 PM CDT Wed Jul 17 2019

   Areas affected...northeast Iowa...southeast Minnesota and southwest
   Wisconsin

   Concerning...Severe potential...Watch possible 

   Valid 180343Z - 180545Z

   Probability of Watch Issuance...40 percent

   SUMMARY...Elevated storms expected to increase in coverage and
   intensity into the early morning from northeast IA into southeast MN
   and southwest WI. Large hail appears to be the main threat, but
   locally strong wind gusts are also possible. It remains uncertain if
   severe threat will become sufficient for a WW, but trends will
   continue to be monitored.

   DISCUSSION...Late this evening, a reservoir of strong instability is
   in place over the central Plains from NE to western IA. A
   southwesterly low-level jet has strengthened to 40 kt resulting in
   low-level theta-e advection and northeast destabilization with time
   is expected across southern MN into western WI. A few elevated
   showers are already initiating in the evolving warm advection regime
   along the instability gradient across north central and northeast
   IA, and additional development is likely farther northeast. The
   thermodynamic environment with steep (7.5-8 C/km) mid level lapse
   rates and 2500-3000 J/kg MUCAPE will promote a risk for large hail,
   and 30-40 kt effective bulk shear may support some mid-level updraft
   rotation in a few storms. The best hail threat will probably be
   within a couple hours of initiation while storms are still discrete,
   but activity might eventually congeal into a small cluster.

   ..Dial/Thompson.. 07/18/2019

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

   ATTN...WFO...DVN...ARX...MPX...DMX...

   LAT...LON   42189252 43039346 43869475 44659413 44669229 43899097
               42469106 42189252