Several systems and the Great Lakes will work together to generate multiple bouts of snow across Ontario this week. Prepare for some travel delays and deteriorating conditions, with the risk for 30-40+ cm of snow in some of the harder-hit areas.
A stalling low over Lake Superior will give big totals downwind of some of the Great Lakes. Meanwhile, a stubborn low will linger over Lake Ontario into Tuesday, bringing periods of unsettled weather at times.
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Expect slower, slippery commutes this week, even with the lighter amounts expected across the Greater Toronto Area (GTA).
Additional rounds of snow with impacts to travel likely this week
With most of the Great Lakes free of ice, the warmer surface water continues to provide instability to sustain low-pressure systems, keeping them borderline stationary.
The stronger jet stream remains farther south, so Lake Superior will continue to inject heat and moisture into the atmosphere, making the low appear anchored over the area into Monday. Snow will continue in northeastern, central, and eastern Ontario, with some passing flurries likely for the GTA.
Baron – Monday afternoon precipitation – Jan13
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As cold air wraps around the low on Monday, lake-effect snow bands will set up for areas downwind of Georgian Bay from Midland to north of Parry Sound. This is where the great snow totals will be in Ontario where locally up to 50 cm is possible. A more widespread 15-30 cm of snow is forecast for most areas.
Snow squalls will also set up for the northern shores of Lake Huron, from the Saugeen Shores to the tip of the Bruce Peninsula.
Wind gusts up to 60 km/h are forecast along Lake Huron and Georgian Bay, while gusts up to 70 km/h are possible along the northern shoreline of Lake Erie.
Baron – Monday evening wind gusts – Jan13
Expect blowing snow around shorelines, roadways and open fields. The worst impacts will be largely in the snowbelts and across northern Ontario, where travel will be locally challenging.
“Snow squalls cause weather conditions to vary considerably; changes from clear skies to heavy snow within just a few kilometres are common,” says Environment and Climate Change Canada (ECCC) in the snow squall warning. “Rapidly accumulating snow could make travel difficult over some locations.”
More squalls pick up Tuesday through Wednesday
On Tuesday, lake-effect snow will continue thanks to the colder air overhead, spilling into Wednesday.
Baron – Ontario Tuesday evening precip – Jan13
As a trough moves through and shifts the winds from west to northwesterly, the snow squalls will be pushed south Tuesday afternoon, which could bring a burst of flurries to parts of the GTA, as well.
Snow squalls will then continue off Georgian Bay and Lake Huron, targeting some different areas. Meaford to Wasaga Beach will see squalls off of Georgian Bay, and then from Grand Bend to the Saugeen shores off of Lake Huron.
Baron – Ontario snow through Wednesday – Jan13
“Prepare for quickly changing and deteriorating travel conditions,” ECCC says. “If visibility is reduced while driving, slow down, watch for tail lights ahead and be prepared to stop.”
Temperatures will become quite cold for the middle of this week, but then will rebound late week and on the weekend to near-seasonal values.
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A rather cold, wintry pattern is expected into the fourth week of January, but a much milder pattern should develop for the first two to three weeks of February, potentially starting during the final few days of January.
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