The first widespread and impactful snowy system of the season takes aim at the Greater Toronto and Hamilton Area, Niagara, and Ottawa through Wednesday. Commuters can expect slow and slippery travel at times throughout the day, so plan to leave plenty of time to get to your destination on time, and safely.
There will be a wide range in snow totals, but many areas will see 5-10 cm by the end of Thursday. Areas along the immediate shorelines will see lower accumulations due to melting snow. Winter weather travel advisories are in effect warning of reduced visibility at times.
For those near Georgian Bay, from Cobourg to Kingston, and along Highway 21, snow squalls are expected, with the threat for blowing and quickly accumulating snow. In some areas, peak snowfall rates could reach 3 to 6 cm per hour, which would result in very poor visibility and driving conditions.
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In addition to the travel risks and delays, it is possible for localized power outages due to the wet nature of the snow. Be sure to stay up to date on all of the weather warnings in your area, and have a plan in place as conditions deteriorate.
The Ontario Provincial Police (OPP) are reminding motorists to ‘know before you go’ and to use resources like 511 Ontario for up-to-date road conditions and closures.
Below is a more detailed look at the forecast.
Wednesday: Snow pushes in, risk for locally heavy accumulations
Although the Greater Toronto Area (GTA) has largely remained snow-free during the recent lake-effect snow events, that will change Wednesday as a clipper system sweeps through. It’s meeting the definition of a clipper, which typically brings more widespread, albeit lighter snowfall.
The system snowfall begins Wednesday morning and will last into Thursday across all of southern and eastern Ontario, and the GTA.
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The difference in air temperatures over the Great Lakes and over land will serve to enhance the snowfall as it moves inland off of the lakes on Wednesday. This will also result in bursts of heavy snow and embedded snow squalls, making for a messy and dangerous situation.
Most major routes will be impacted by the snow, but commuters in the southern Niagara region, as well as along Highway 401 east of Toronto up to Kingston, will be at an increased risk of significant snowfall accumulations and whiteout conditions.
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Snowfall rates of 2-5 cm/h in these areas, paired with 50-70+ km/h wind gusts across southern Ontario, will rapidly deteriorate road conditions and impact the Wednesday and Thursday commutes.
Historically, the first major snowfall of the season leads to increased accidents and traffic slowdowns, so folks in these specific areas should consider working from home and avoiding travel if possible.
In the GTA, areas along the immediate shorelines will see lower accumulations, limited to just a few centimetres due to melting snow. Meanwhile, areas a few kilometres inland can see 5-10 cm. The snow will fall in multiple bursts through the day, and conditions can change rapidly.
Parts of cottage country will not be spared from this system either, as snow will be coming off of Lake Michigan and Huron, and Georgian Bay.
Some locales could see 20-40 cm, with extreme amounts exceeding 50 cm. Luckily, those at risk will are north of the areas that saw the 100+ cm over the weekend. Areas along eastern Lake Ontario may see 10-25 cm.
Thursday: Another round of snow squalls as the system departs
The snowy and blustery conditions will continue into the Thursday morning commute.
Bursts of heavy snow and snow squalls will continue through Niagara and in the snowbelts following the system’s exit in the morning.
Difficult travel is expected, especially near Lake Huron and south of Georgian Bay, during the day Thursday. While snow totals will not be nearly as impressive as what accumulated this past weekend, travel conditions will still be dangerous due to the blowing snow and very poor visibility.
Snow will continue to fall over the Ottawa region through Thursday afternoon before tapering off heading into the evening.
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Lake-effect snow will linger into Friday, but the wind speeds will relax. Thursday night and Friday morning will bring the coldest temperatures of the week.
Milder and changeable temperatures are expected for next week, with a more active pattern kicking in for mid and late December. There’s the potential for messy systems and rain, as the region will become the battleground between the Arctic air to the northwest, and much milder weather to the south.
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Keep safety in mind
The OPP reminds motorists to ensure they are prepared for any situation by driving appropriately for the road and weather conditions. Remember to have an emergency kit in your vehicle, ensure sufficient fuel/battery level with a reserve, and plan ahead by monitoring local media reports for road conditions and weather updates.
Motorists who find themselves stranded on roads are encouraged to remain calm, stay in their vehicle, and consider teaming up with other drivers until help arrives.
The OPP is working with the Ministry of Transportation and other road crews to keep an eye on the weather and get ready for any upcoming storms.
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More snow ahead
As this current clipper departs, the coldest air of the season so far will spread across the region on Thursday night, Friday, and into Saturday.
A weak system will reinvigorate the bands of lake-effect snow Friday evening through Saturday morning with difficult travel on Highway 11 & the 400 north of Barrie to near Parry Sound and south of Huntsville.
Meanwhile, we’re also monitoring another clipper, which is expected to track north of the region late Saturday with widespread snow, primarily north and east of Toronto, with 2 to 5+ cm of snow. The plus side to this system is that it will also cause a warm front to lift north, bringing in much milder temperatures for Sunday—rising well above freezing.
Stay with The Weather Network for more forecast information and updates on your weather across Ontario.