Mesoscale Discussion 1430
   NWS Storm Prediction Center Norman OK
   1103 AM CDT Sat Aug 07 2021

   Areas affected...Portions of southeastern MN...northeastern IA...and
   western WI

   Concerning...Severe potential...Watch possible 

   Valid 071603Z - 071830Z

   Probability of Watch Issuance...40 percent

   SUMMARY...A threat for large hail, damaging wind gusts, and perhaps
   a few tornadoes may increase through the early afternoon. Watch
   issuance is possible.

   DISCUSSION...Recent visible satellite and radar imagery clearly
   shows a MCV moving quickly eastward across MN and towards
   west-central WI late this morning. On the southern flank of this
   feature, a 25-35 kt southwesterly low-level jet has encouraged a
   recent uptick in convection across southeastern MN and northeastern
   IA. It appears that this activity is mainly elevated at the moment,
   with a weak front/outflow boundary located over southern MN. Still,
   with around 35-40 kt of deep-layer shear present, any elevated
   supercells may pose an isolated threat for primarily large hail in
   the short term. Storms may eventually transition to surface-based
   over the next few hours, particularly along and south of the
   convectively reinforced boundary over southern MN.

   A rich low-level airmass characterized by at least low 70s surface
   dewpoints is present across much of IA into southern MN. Both
   diurnal heating of this airmass and the presence of steep mid-level
   lapse will likely contribute to around 2000-3000 J/kg of MLCAPE this
   afternoon. In addition to the large hail threat with any supercells,
   damaging winds may also occur if storms can congeal into one or more
   clusters and then move east-southeastward along the surface boundary
   into western WI. 25-35 kt of southwesterly winds in the boundary
   layer and a veering wind profile with height should support 100-200
   m2/s2 of 0-1 km SRH, sufficient for updraft rotation and a threat
   for a few tornadoes. This tornado threat will probably be maximized
   near the surface boundary across parts of southern MN into far
   northeastern IA and southwestern WI. Convective trends will be
   closely monitored for possible watch issuance in the next few hours.

   ..Gleason/Thompson.. 08/07/2021

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

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

   LAT...LON   43548995 42998986 42689018 42539067 42409221 42669321
               42949368 43929391 44389282 44439206 44209109 43548995