Environment Canada is predicting as much as 20 millimetres of rain to fall between now and Friday afternoon.
The national forecaster has issued a special weather statement calling for pooling and possible flooding from the rain mixed with a quick thaw.
Environment Canada says that will change on Friday afternoon as rain will change to snow quickly with temperatures dropping below the freezing mark.
Expect quick freezes making roads and sidewalks slippery when the cold returns.
