Mesoscale Discussion 0735
   NWS Storm Prediction Center Norman OK
   1229 PM CDT Tue May 26 2020

   Areas affected...Parts of northern Missouri into central Iowa

   Concerning...Severe potential...Watch possible 

   Valid 261729Z - 261930Z

   Probability of Watch Issuance...60 percent

   SUMMARY...The risk for tornadoes in association with intensifying
   thunderstorms may increase near the Interstate 35 corridor,
   including the Greater Des Moines area, through 2-4 PM CDT.  Trends
   are being monitored for the possibility of a severe weather watch.

   DISCUSSION...Insolation already appears to be contributing to modest
   boundary-layer CAPE (up to around 1000 J/kg) within the warm sector
   of a 1006 mb surface low currently centered southwest of Kansas
   City, MO.  This is supporting bands of deepening convective
   development to the northeast of the low, perhaps aided by forcing
   associated with an increasingly sheared mid-level perturbation. 
   With continued surface heating and destabilization, this activity is
   expected to gradually intensify through early/mid afternoon, while
   spreading northward across north central Missouri, toward central
   Iowa.

   This is occurring beneath a band of 40 kt southerly 500 mb flow,
   which is contributing to sufficient deep-layer shear to support
   organizing thunderstorms, including supercells.  This is also near
   the nose of 30-40 kt southerly 850 mb flow, which is forecast to
   continue gradually shifting north of the Missouri/Iowa state border
   through late afternoon.  

   Strongest low-level shear, including clockwise-curved low-level
   hodographs, are generally focused to the immediate northeast of the
   surface low, and along a broad frontal zone extending to the north. 
   The frontal zone may remain quasi-stationary, roughly near the
   Interstate 35 corridor, while the surface low migrates toward the
   St. Joseph, MO through 19-21Z.  

   Given the low-level shear, in addition to the favorable ambient
   vertical vorticity, focused near these surface features, in
   combination with the relatively moist and destabilizing boundary
   layer, the environment may become increasingly conducive to tornadic
   development.  With increasing distance to the east of the I-35
   corridor, tornadic potential appears lower, but stronger convection
   may still become capable of producing strong surface gusts
   approaching severe limits.

   ..Kerr/Hart.. 05/26/2020

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

   ATTN...WFO...DVN...DMX...EAX...

   LAT...LON   40279459 41289476 42149435 42689368 42299224 41149203
               39619272 39569391 40279459