A low-pressure system that is moving into Southwestern Ontario has already brought some rain, but it is also expected to usher in a messy mix of rain and wet snow, about 15 to 20 centimetres.
Environment Canada has issued a special weather statement about an incoming weather system that is intensifying in the United States and is expected to touch much of southern and eastern Ontario in the days ahead.
It is believed that parts of what Environment Canada describes as “extreme southwestern Ontario” will be hit with “various mixtures of wet snow and rain.”
The system began to hit parts of the province Tuesday afternoon, with rain already being reported in Windsor, according to the CBC Weather Centre.
A snowfall warning is in effect for Toronto, Hamilton, Halton-Peel, York-Durham, Huron-Perth, Waterloo-Wellington and Dufferin-Innisfil, Environment Canada said Tuesday.
Windsor is likely to see rain ahead of a messy mix of precipitation, turning into wet snow by Tuesday night, said CBC meteorologist Jay Scotland.
The weather system is then expected to move northeast towards the Niagara Peninsula.
That same mix is expected to reach the Greater Toronto Area on Tuesday evening, he added. Overnight, the weather system will move towards the Peterborough area and the Kawarthas.
Parts of Ontario are expected to receive snowfall amounts ranging from two centimetres in Ottawa to as much as 19 centimetres in the Toronto area, Scotland said.
Windsor and London could receive as much as 12 centimetres of wet snow, while Muskoka and Kingston could accumulate as much as eight centimetres and 13 centimetres, respectively.
From extreme southwestern Ontario, up to Niagara, the heaviest snow is likely to occur overnight into the early morning rush hour, Environment Canada said in its special weather statement.
"Motorists should adjust travel plans accordingly as this snowfall event may have a considerable impact on the morning commute to work," it said.
But cities closer to Lake Erie and Lake Ontario will see more rain, due to milder temperatures, it added.
CBC meteorologist Claire Martin said that Toronto is likely to see smaller amounts of precipitation, but higher amounts are expected around the city.
"This will be a slushy affair to start – rain starting and then turning to snow – as we go through the overnight period into Wednesday morning," she said.
Porter Airlines issued a travel advisory for flights out of Toronto, Chicago and Windsor for both Tuesday and Wednesday. Air Canada issued a travel alert on Tuesday, and some flights have been cancelled. Both airlines are recommending travellers check their flight status before heading to the airport.
Farther northeast, near Barrie, Peterborough and Kingston, both the morning and evening commutes on Wednesday will be quite slow.
"Driving conditions are expected to deteriorate and may become hazardous due to rapidly accumulating snow on untreated roads and low visibility in heavy snow," Environment Canada says.
However, it is unclear what mix of snow, rain or wet snow these areas will receive.
Martin said the incoming system is very similar to the one that moved through the province just two weeks ago.
"Snow now through Kansas, Oklahoma, some of it still lingering in through parts of Texas and a wide swath of storms in advance of it," Martin reported on Monday evening. "This beast will make its way towards us."