Anything is possible this week, as far as Canada's weather is concerned, with forecasts ranging from scorching heat in some parts of the country to rain and snow in others.

Humidity and high temperatures are expected across the Great Lakes region today, with parts of southwestern Ontario expected to reach daytime highs near 31 C and humidex values in the mid-thirties.

In those parts of the province, the overnight low is only expected to drop to 21. Temperatures are expected to cool slightly Wednesday, and Environment Canada reports showers and thunderstorms are possible through the day.

While southwestern Ontario is under a special weather statement for heat, northern Ontario and B.C. are under advisories for snow expected to fall later this week.

Parts of northern Ontario can expect as much as 30 to 60 millimetres of rain at first, with wind gusts up to 70 km/h through Wednesday, thanks to a strong low-pressure system forecast to track west of Lake Superior that day. By Thursday, areas northwest of Thunder Bay could see snow accumulation.

Snow is also expected in the mountain passes of B.C. as an upper trough of low pressure brings a cooler air mass to the southern B.C. Interior. Snowfall will begin Tuesday night into Wednesday morning. By Wednesday afternoon, B.C.'s mountain passes could see two to four centimetres of accumulation.

Environment Canada warns the snow could impact transportation routes, and says travellers should be prepared for weather conditions to change quickly. Meanwhile, a reduced air quality advisory remains in place for parts of northeastern B.C., due to wildfire smoke.

Temperatures in the Prairies this afternoon are trending slightly below seasonal, with frost advisories in place this morning across southern and central Alberta and southern Saskatchewan. Environment Canada has issued a funnel cloud warning for a large swath of southern Saskatchewan.

"If conditions become more favourable for the development of landspout tornadoes, watches and warnings will be issued by Environment Canada," the warning reads.

"Treat any funnel cloud sighting seriously. Should a funnel cloud develop nearby, prepare to take shelter. These funnel clouds usually appear with little or no warning."

Parts of southern Quebec, from Pontiac east to Lac Megantic, are under a severe thunderstorm watch as of Tuesday afternoon, with Environment Canada warning the conditions are in place for "dangerous thunderstorms capable of producing very strong wind gusts," along with large hail and heavy rain.

"Very strong wind gusts can damage buildings, down trees and blow large vehicles off the road," the advisory reads. "Water-related activities may be unsafe due to violent and sudden gusts of wind over bodies of water.

Environment Canada has lifted the strong wind warnings it issued Tuesday morning for coastal areas in eastern and northeastern Nova Scotia, and northern Prince Edward Island.

With files from CTV's Your Morning meteorologist Kelsey McEwen