Mesoscale Discussion 1148
   NWS Storm Prediction Center Norman OK
   0538 PM CDT Mon Jun 13 2022

   Areas affected...Northeast Illinois...southeast Wisconsin
   (enclosed escalloped area in headlined map)

   Concerning...Severe potential...Tornado Watch likely 

   Valid 5:38PM - 7:45PM CDT

   Probability of Watch Issuance...95 percent

   SUMMARY...Thunderstorms are developing in a very unstable and highly
   sheared environment. A tornado watch will likely be needed to
   address this concern.

   DISCUSSION...Thunderstorms have developed along a warm frontal
   boundary across northern IL within the past hour. The downstream
   environment remains highly unstable per latest RAP mesoanalysis
   (4000-5000 J/kg MLCAPE), and VWP observations from KLOT show around
   200 m2/s2 0-1 km SRH. These observations support latest 6+ STP
   estimates that were recently analyzed in recent data. While the
   propensity for discrete convection is unclear due to storm motions
   along the surface boundary and several updrafts in close proximity,
   the environment is supportive of a tornado threat. A tornado watch
   is likely in the next hour to address this concern.