The Greater Toronto Area is preparing for a mix of snow and rain overnight that is expected to create a sloppy mess in the region, just in time for the Wednesday morning commute.

Environment Canada has issued a special weather statement about the incoming weather system that is intensifying in the United States and is expected to dump snow, rain and freezing rain on much of southern and eastern Ontario in the days ahead.

The system began to hit parts of the province Tuesday afternoon, with rain and snow reaching Windsor.

A snowfall warning is in effect for Toronto, Hamilton, Halton-Peel, York-Durham, Huron-Perth, Waterloo-Wellington and Dufferin-Innisfil, Environment Canada said Tuesday.

Messy mix predicted

That mix of snow and rain is expected to reach the GTA late Tuesday night, said CBC meteorologist Jay Scotland.

The weather system will continue to 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.

The City of Burlington — west of Toronto — issued a statement on Tuesday evening advising residents it was closing all recreation facilities in the city on Wednesday morning until 1 p.m. City Hall, it said, would remain open.

Flight cancellations, travel alerts

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 the Toronto island Billy Bishop Airport , Chicago and Windsor for both Tuesday and Wednesday.

Air Canada also issued a travel alert on Tuesday, and some flights have been cancelled at Pearson Airport.

Both airlines are recommending travellers check their flight status before heading to the airport.

Outside of the GTA, 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 Tuesday evening. "This beast will make its way towards us."