Mesoscale Discussion 0278
   NWS Storm Prediction Center Norman OK
   0623 PM CDT Fri Mar 28 2025

   Areas affected...Far southeast Minnesota and northern/central
   Wisconsin

   Concerning...Severe potential...Watch unlikely 

   Valid 282323Z - 290200Z

   Probability of Watch Issuance...5 percent

   SUMMARY...A couple instances of marginally severe hail (around 1
   inch) are possible through around 03Z.

   DISCUSSION...The latest radar and IR satellite imagery show a
   gradual increase in ascent along/immediately north of a warm front
   draped across portions of central WI -- ahead of a weak surface low
   over southeast MN. This is associated with gradually strengthening
   warm advection in the vicinity of a coupled upper-level jet
   structure. A steep midlevel lapse rate plume extending eastward into
   the area (see earlier 12Z upstream soundings) is contributing to
   around 1000 J/kg MUCAPE, which may increase to around 1500 J/kg as
   ascent moistens the base of the EML. This instability and around
   40-50 kt of cloud-layer shear (per regional VWP data) may promote a
   couple loosely organized supercell structures capable of producing
   hail to around 1 inch in diameter. While the majority of this
   activity is expected to remain elevated, a couple ongoing cells in
   southeast MN into west-central WI are evolving within or slightly on
   the warm side of the baroclinic zone. Even so, isolated severe hail
   should still be the primary hazard.

   The severe-hail risk should generally persist through around 03Z,
   before cellular convection is expected to diminish amid weakening
   instability/midlevel lapse rates.

   ..Weinman/Mosier.. 03/28/2025

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

   ATTN...WFO...GRB...DLH...ARX...MPX...

   LAT...LON   44018942 43939152 43919237 43989285 44499320 44919312
               45349273 45549210 45589125 45368815 44958768 44458783
               44098819 44018942 

   MOST PROBABLE PEAK HAIL SIZE...UP TO 1.25 IN