A wet winter storm sweeping through Ontario will bring disruptive snow to the northern part of the province on and through the weekend, with up to 60cm of fresh snow possible north of Lake Superior.
People across southern Ontario will exceptionally fall on the warmer side of this system, with a steady and soggy rain coming on tap for St. Patrick’s Day.
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A huge low-pressure system moving into the Great Lakes will pull a lot of moisture north of the boundary. Storms in the early spring months can result in increased snowfall as they open up a deep reservoir of tropical moisture that flows up from the south and west.
That whiff of evaporated paradise, pouring in from Hawaii and Mexico, will fall in abundance over Ontario over the next few days.
Widespread winter storm warnings are in place for part of northern Ontario as a prolonged snow event that began Thursday will bring significant buildup to the area through Saturday.

“Snow can accumulate quickly and visibility can be significantly reduced at times,” Environment and Climate Change Canada (ECCC) said in its winter storm warning for the region, including the communities of Timmins and Thunder Bay.
“There may be significant travel delays and road closures,” ECCC added. “Consider postponing non-essential travel until conditions improve.”
Locally strong winds of between 45 and 50 mph and snow will result in whiteout conditions for roads and communities along Lake Superior’s north and east shores through Friday.
The trace of this low-pressure system will bring the deepest snow northeast of Lake Superior, with more than 40 cm of snow possible in Timmins, Kapuskasing, Chapleau and Wawa. The woods between these communities could see up to two feet of snow, or about as much snow as two corgis stacked on top of each other. (Please do not attempt this at home.)
Impressive snow cover of 20-40 cm is likely further west along the Superior Coast towards Thunder Bay. Farther south, however, snowfall totals are trending down as the storm’s trail is trending north.
Sault Ste. Marie and Sudbury will see snow turning to rain at the beginning of the storm, and rain turning back to snow again at the end of the storm. The total amount of these two rounds of snow add up to about 5-10 cm in each community, with the total increasing rapidly north and decreasing rapidly south.
A warm front moving along the south side of the low will keep things warm enough for precipitation to remain rain in southern Ontario at first. Widespread rainfall of 10-20mm is possible through Friday, with 15-25mm of rain possible along the Huron coast.
This rain shouldn’t be a big deal in itself, but road and parking lot waterlogging is possible in places where storm drains are still clogged with snow.
WATCH NOW: Travel hazards due to snow gusts in Ontario
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Unfortunately, the rise in milder temperatures on Friday will prove short-lived as a cold front that follows soon after will quickly bring temperatures back down from Friday night into Saturday.
Pressure from colder air blowing across the largely ice-free lakes will bring lake-effect snow gusts to southern Ontario on Saturday and Sunday.
Gusty winds of 40-70km/h will accompany this weekend’s snow squalls, making for limited visibility during periods of heavy snowfall and stormy conditions. Visibility can change rapidly over short distances around snow gusts. Travelers should prepare for dangerous driving conditions, especially with additional traffic on the roads as people return home from the March break.
Beyond that system, Ontario will be greeted by nicer weather as the new workweek begins, with calmer conditions and near-seasonal temperatures expected when astronomical spring arrives on Monday. Forecasters are watching the potential for another system to arrive in the second half of the week.
Stay tuned to The Weather Network for the latest weather conditions across Ontario.