5-10+ cm: Closely watching a Sunday snowmaker in southern Ontario
Ready or not, signs of snow are creeping into the forecast, with all eyes on Sunday's set-up and the potential for some messy wintry conditions in southern Ontario
Southern Ontario is bracing for an active weather pattern heading into the weekend. All eyes are on a developing storm expected to move into the Great Lakes region on Sunday, potentially bringing a mix of precipitation to the area.
North of the storm track, substantial wet snowfall is anticipated, with accumulations surpassing 10 cm in areas such as cottage country, Haliburton, and regions east of Lake Huron and Georgian Bay. Meanwhile, areas near and south of the track, including parts of the Greater Toronto Area (GTA), could see a rain-and-snow mix or primarily rainfall. The storm's exact path remains uncertain, presenting the possibility of significant impacts if it shifts southward.
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Residents are advised to monitor any developing weather alerts and to prepare for potentially slippery roads and reduced visibility in affected areas.
Signs of winter arrive Thursday
Some localized areas in northern Ontario experienced accumulating snow on Thursday morning, offering an early glimpse of winter and leading to challenging travel conditions.
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While it's still the beginning of November, these early season snowfalls remind residents to prepare for shifting driving conditions and ensure vehicles are winter-ready.
Sunday: Two scenarios unfolding for weekend snow in southern Ontario
A significant weather system on Sunday could bring widespread snowfall to southern Ontario, as Arctic air filters in behind the storm. The storm's track will be critical in determining precipitation type and accumulation across the region.
If the system tracks southward, snowfall is possible near the 401 corridor, while a northern track could introduce rain or a rain-snow mix, particularly for areas like the GTA lakeshore, Niagara, and Ottawa where temperatures may hover slightly above 0°C.
Snow is most likely in regions north of the 401, snowbelts, higher elevations, and areas further east, where accumulation could disrupt travel.
Temperatures close to or below 0°C Sunday morning and afternoon will support potential snow-covered or icy roads, increasing the risk of slow driving conditions.
Road closures north of the 401 are also possible. Residents without winter tires should exercise extreme caution.
Current storm confidence and uncertainty: All eyes on the track
There is a potential for 5-15 cm of snowfall in the hardest-hit areas, though there is still uncertainty about the exact locations. Regions north of the 401 and the snowbelts are the most likely to see significant accumulation.
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The storm track will play a key role in determining snowfall amounts, as any shift in its path could lead to substantial changes.
Confidence is highest for snowfall in the snowbelt regions and areas north of the 401 corridor. Meanwhile, the likelihood of significant snowfall remains lower for areas along the Lake Erie shoreline, Niagara, Hamilton, and downtown Toronto.
Lake-effect snow chances increase early next week
Following the system, persistent Arctic air will drive multiple days of lake-effect snow in the traditional snowbelt regions on Monday and Tuesday.
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A wintry December is coming
Temperatures early next week will remain chilly, with values struggling to reach the low single digits near and south of the 401, while staying below freezing in areas well north of the 401.
A gradual temperature rebound is anticipated later in the week, with above-seasonal conditions expected as the region moves into the second half of November. However, more consistent winter weather is anticipated to settle in before the start of December, with December shaping up to feature decidedly wintry conditions.
Safety tips for driving in adverse weather
Install winter tires. Winter tires can improve stopping distance by up to 30 per cent in wintry conditions.
Prepare an emergency kit. Include the basics like snacks, first aid kit, flashlights and blankets.
Plan your travel. If possible, postpone trips during active weather and especially freezing rain. Driving is not worth the risk.
Adjust your speed. A gentle reminder that stopping distance increases exponentially as your speed increases.