We could see significant rain Monday night into Tuesday morning.
Environment Canada has extended a special weather statement to include Sarnia-Lambton.
A weather system moving along the line of a warm front over northern Ohio will affect southern Ontario near midnight with a significant rainfall. Showers and embedded thunderstorms will soak the region overnight and into Tuesday.
A widespread rainfall of 20 to 40 mm is expected with total amounts of 50 mm (2 inch) or more possible in a few areas that receive a thunderstorm or two.
The rain will come to an end by Tuesday afternoon as the front is pushed back well to the south of the area.
Motorists should be prepared for ponding of water on poorly drained sections of roads, and low visibility in heavy downpours.
Environment Canada says it's closely monitoring the situation and rainfall warnings could be issued.
