Environment Canada has issued a special weather statement for Sarnia-Lambton.
The weather agency says showers and thunderstorms are moving northeast across the area this morning, and some thunderstorms contain very heavy downpours. Local rainfall amounts of 20 to 40 millimetres in an hour or less are possible.
Frequent lightning and winds gusting to near 60 kilometres an hour are also associated with some of the strongest thunderstorms.
Motorists are reminded to watch for ponding on roads and be prepared for sudden low visibility in heavy downpours.
Forecasters say the thunderstorms will move out of the area late Tuesday morning.
