For the following areas...
Open Waters from Winthrop Harbor to Michigan City out to Mid Lake...
At 429 AM CDT, a severe thunderstorm was located 18 nm east of Wilmette Harbor, moving southeast at 25 knots.
HAZARD...Wind gusts 34 knots or greater and large hail.
SOURCE...Radar indicated.
IMPACT...Small craft could be damaged in briefly higher winds and suddenly higher waves. Large hail could result in structural damage.
The severe thunderstorm will remain over mainly open waters.