A large and moisture laden low from the Southeastern United States will track northward into Ohio Tuesday, bringing a large area of precipitation with it to southern and Eastern Ontario.
Environment Canada is calling for heavy rain with rainfall totals reaching 50 mm in many areas tonight and Tuesday. Rain ahead of this disturbance will arrive over Southwestern Ontario by early Monday evening. The rain will come down quite heavy at times resulting in rainfall amounts reaching or possibly exceeding 50 mm in many areas by Tuesday night.
A rainfall warning is in effect for Southwestern Ontario regions as far northeast as London. Motorists should be prepared for poor visibility in periods of heavy rain tonight and Tuesday, making driving conditions difficult.