Violent thunderstorms rattled northern Lower Michigan last night and early today, and more bad weather could be headed for the southern Lower Peninsula.

Utility crews are racing to restore electrical service to customers in metropolitan Detroit ahead of another possible round of rough weather.

Tornado warnings for Lake, Mason, Missaukee and Wexford counties in northwest Lower Michigan were in effect for several hours last night. Authorities say they received no immediate reports of injuries or property damage.

Storms hit Lower Michigan a week ago today and continued until Tuesday, knocking out power to at least 730,000 utility customers and claiming eight lives.