"Rainfall amounts will generally be in the 20 to 40 mm range, with locally up to 50 mm possible in thunderstorms in some locales," an Environment Canada statement said.

The Toronto Region Conservation Authority has issued a warning saying Lake Ontario water levels remain high with "risks" during heavy wind or wave activity following Wednesday's heavy rain.

Locally, heavy rainfall accumulations of 20 to 40 mm are expected by the time precipitation comes to an end in Toronto and surrounding areas like Durham, Peel, Halton and York regions.