Mesoscale Outlook – Severe Thunderstorm Watch could be extended into the Chicago area later this afternoon/evening

...The National Storm Prediction Center latest discussion...

The severe weather threat for Severe Thunderstorm Watch 203
   continues.

   SUMMARY...The severe risk continues across remaining-valid portions
   of Severe Thunderstorm Watch 203 and may spread farther east/south.
   Additional Watch issuance and/or Watch extension may be considered.

   DISCUSSION...A cluster of thunderstorms has consolidated into a
   somewhat more organized squall line from southeast IA to far
   north-central MO. This activity will continue advancing generally
   eastward along a baroclinic zone, with some tendency for southward
   development into a destabilizing environment south of the boundary.
   A few storms may also continue to develop ahead of this activity.
   With around 45-55 kt of effective shear, this activity will likely
   continue to exhibit organization into the early evening hours.
   Isolated to widely scattered severe wind/hail will remain possible,
   along with some potential for a brief tornado. Downstream Watch
   issuance may eventually be considered, and local extensions of Watch
   203 may also be considered. Behind the squall line, the severe risk
   will markedly diminish.