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Mesoscale Discussion 1787 NWS Storm Prediction Center Norman OK 0740 AM CDT Sun Aug 18 2019 Areas affected...southeast Wisconsin... northeast Illinois...northwest Indiana ...and southwest Michigan Concerning...Severe Thunderstorm Watch 597... Valid 181240Z - 181445Z The severe weather threat for Severe Thunderstorm Watch 597 continues. SUMMARY...Thunderstorms continue this morning across the region. Moderate instability and sufficient shear should continue to support a severe threat this morning. DISCUSSION...Initial line of thunderstorms has weakened considerably this morning as increasing precipitation ahead of the line -- stemming from thunderstorms that developed south-southwest of Chicago -- has acted to stabilize the airmass across north-central Illinois and southern Wisconsin. The strongest thunderstorm cluster from this original band of storms is currently located across southeast Wisconsin and will have the potential to pose a severe threat for another couple hours before moving east over Lake Michigan. As previously mentioned, additional thunderstorms developed to the south-southwest of Chicago, ahead of the original line of storms. These thunderstorms are within a better severe thunderstorm environment than those to the north given less convective coverage allowing most-unstable CAPE values to approach 2000 J/kg, and thus have a greater potential to pose a severe wind or hail threat. At present, these storms will move across the greater Chicago metro over the next 1-2 hours, with hail and wind threats likely. These storms will continue east-northeast through the morning, eventually moving over Lake Michigan.