Heavy rain is in the forecast for Sarnia-Lambton Monday.
Environment Canada issued a special weather statement at around 5:40 a.m. Sunday. The statement was upgraded to a rainfall warning just after 11 p.m.
The weather agency said total rainfall amounts of 40 to 60 millimetres are possible by Monday evening, and that localized flooding in low lying areas is also possible.
Motorists are reminded that heavy downpours can cause water pooling on roads and reduced visibility.
The rainfall is due to a low pressure system that is forecast to track northeast across southern Ontario on Monday.