Toronto could potentially see between 15 to 25 millimetres of rainfall tonight and into Wednesday, Environment Canada has reported.
Localised flooding in low-lying areas of the city is possible as rainfall, combined with melting snow, soaks Toronto beginning tonight.
In a special weather alert, Environment Canada warned that the frozen ground has a reduced ability to absorb the water, meaning pooling alongside roads is also possible.
Heavy rain and mild temperatures could turn into thunderstorms as the evening progresses, the weather agency said.
Rainfall amounts exceeding 25 millimetres cannot be ruled out for Wednesday night.
The Toronto and Region Conservation Authority (TRCA) on Tuesday afternoon said potential flood hazards could remain until late Friday.
These hazards include flooding from river systems in the conservation authority’s watershed due to rain, as well as snow and ice melting to cause potential surface runoff and ice jams.
The TRCA has advised locals to use caution around bodies of water, rivers, streams and the Lake Ontario shoreline.
Recreational activities surrounding water, including fishing, canoeing and hiking can be impacted by rapidly changing weather conditions, the TRCA said.
Tuesday's temperatures are expected to reach 5 C during the day and drop to 3 C at night, while Wednesday's temperature is forecast to go up to 8 C and fall to 2 C by the evening.
