Environment Canada ended a severe thunderstorm warning for Sarnia-Lambton at 3:40 p.m. Sunday.
Meteorologsts were tracking a severe thunderstorm capable of producing very strong wind gusts, pea to dime size hail and heavy rain.
A line of storms over lower Michigan reached the Sarnia area near 3:30 p.m.
Damaging wind gusts to 100 kilometres per hour were the main threat.
The weather agency said the strongest thunderstorms remained over Michigan.
The U.S. National Weather Service had a tornado warning in effect for a while at mid-afternoon for northern St. Clair County. There was concern about rotation in a storm cell that moved over Port Huron on a northeast track just west of Sarnia.
A severe thunderstorm watch remained in effect for Sarnia-Lambton until 10:30 p.m. as a cold front approached from the west.
The temperature is forecast to drop to 11 C, 52 F, in Sarnia in the afternoon holiday Monday.