Environment Canada says a developing low pressure system over Texas is setting its sights on southern Ontario. It will slowly track towards the lower Great Lakes later Thursday and linger on Friday.
Rain is forecast to begin Thursday for much of Southwestern Ontario reaching the Golden Horseshoe later in the day.
It is expected to change to snow in some areas, and then to freezing rain Thursday night north and west of Toronto.
Those in the Greater Toronto Area in closer proximity to Lake Ontario, as well as most of southwestern Ontario, should receive mostly rain.
Most areas should change to rain by Friday, with some significant rainfall totals of 25 to 40 mm possible before it begins to taper off Friday night.
Travel may become hazardous in areas which receive freezing rain or snowfall Thursday night. Warnings will likely be required.
The forecast for Windsor-Essex is calling for 15 to 20 millimetres of rain on Thursday with another 10 mm on Friday.
A special weather statement was issued for Windsor-Essex earlier today but has since been cancelled by Environment Canada.