Return of Squalls to Ontario’s Snowbelt This Week With Blizzard Conditions & Over 50cm of Snow Possible

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While the brief break from lake-effect snow earlier this month brought milder air and rain to the snowbelt regions, the respite appears to be short-lived.

Snow squall activity is expected to make a comeback as we approach the end of the week. With multiple days of snow squalls anticipated, we could once again see impressive snowfall totals, rivaling those from earlier this month.

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Colder air will begin to filter into Southern Ontario from the northwest late Wednesday afternoon, dropping temperatures below freezing through the evening. This influx of cold air will trigger the development of lake-effect snow bands, with ideal conditions persisting through Thursday and into Friday.

Current projections suggest two primary zones will bear the brunt of the snow squalls: one east of Lake Huron and the other southeast of Georgian Bay. The Lake Huron squall is expected to impact southern portions of Grey and Bruce counties, including Owen Sound, Chatsworth, and Meaford. Meanwhile, the Georgian Bay squall will likely target central Simcoe County, extending northward into southern Muskoka.

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Snowfall totals in the hardest-hit areas could exceed 50 cm, with the possibility of approaching the staggering 100 cm seen in Bracebridge and Gravenhurst earlier this month. Whether such totals materialize depends on whether any of the snow squall bands remain stationary for extended periods.

To make matters worse, strong winds are expected to develop late Wednesday and persist into Thursday morning. Gusts could reach 60–80 km/h, particularly in Grey-Bruce and Simcoe County, significantly reducing visibility and creating hazardous travel conditions.

Blizzard conditions may develop, and travel is strongly discouraged during this timeframe. School bus cancellations are almost certain along the Lake Huron and Georgian Bay shorelines on Thursday.

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HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

The lake-effect snow is expected to begin late Wednesday afternoon, with the first band forming off Lake Huron. Initially driven by northwesterly winds, this band will target areas near Goderich before shifting northward as winds veer to a more westerly direction by evening.

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By midnight, the main Lake Huron squall is expected to become stationary, affecting areas from Wiarton southward to Port Elgin, Owen Sound, and Meaford. Simultaneously, snow bands will begin forming off Georgian Bay, initially targeting Wasaga Beach, Midland, and Orillia. These may briefly lift northward Thursday morning, potentially reaching Gravenhurst and Bracebridge.

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The most intense conditions are forecast for late Thursday morning into the afternoon. Two main corridors of concern are expected: Owen Sound to Collingwood off Lake Huron, and Wasaga Beach to Orillia off Georgian Bay. Snowfall rates will be exceptionally high, and the squalls could remain locked in place for 6–12 hours, leading to rapid accumulation.

Strong wind gusts during this period could result in blizzard conditions, with near-zero visibility on roads. Road and highway closures are likely in the hardest-hit areas, especially on Thursday.

By late Thursday night, the snow squalls may shift into the Bruce Peninsula and Muskoka regions. While the bands are expected to weaken by Friday morning, lingering activity could still produce scattered flurries before tapering off completely by the afternoon.

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As with previous lake-effect events, it’s important to remember that these snow squalls are highly localized. Narrow bands of snow, often only a few kilometres wide, can result in dramatically different conditions over short distances. One location might see over 50 cm of snow while areas just a few kilometres away remain relatively unscathed.

We currently have high confidence in two zones being hardest hit: southern portions of the Bruce Peninsula, including Owen Sound, Chatsworth, Meaford, and Flesherton, and areas west of Orillia, including Midland and Coldwater. Accumulations in these regions could exceed 50 cm, with totals potentially nearing 100 cm if squalls remain stationary long enough. A more conservative estimate is 50–75 cm.

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A wider swath of Grey-Bruce, including Kincardine, Port Elgin, Hanover, Lion’s Head, and Tobermory, as well as much of Simcoe County and northern portions of Kawartha Lakes, Gravenhurst, and Beaverton, could see 25–50 cm. Not all areas in this zone will hit these totals, as much depends on the placement and movement of the snow bands.

Further south and away from the snowbelt, accumulation decreases rapidly. Barrie itself may largely miss the snow, although it could see up to 25 cm if the bands shift slightly. The Georgian Bay squall may extend inland at times, bringing heavy snow to Lindsay and Peterborough, with 10–20 cm possible in these areas.

For regions in other parts of the snowbelt, including Muskoka, Parry Sound, Haliburton, and parts of Dufferin, Wellington, Perth, and Huron counties, totals are expected to range from 10–20 cm. The Golden Horseshoe, including London, Kitchener, and Guelph, will likely see only light flurries, with less than 5 cm expected.

London Area Could Get Hammered by Intense Snow Squall on Thursday With Locally Up to 50-75cm of Snow

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As the Alberta Clipper that brought widespread snowfall to Southern Ontario exits late Wednesday, snow squalls are set to return to the snowbelt regions. Unfortunately, the areas that were buried earlier this week will once again bear the brunt of this lake effect activity.

Locations just north and west of London appear to be in the bullseye, with the potential for 50 to 75 cm of fresh snowfall accumulation by the end of Thursday.

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Lake effect activity is expected to begin organizing overnight and into early Thursday morning along the southern shorelines of Lake Huron and Georgian Bay. Current forecasts suggest this activity will consolidate into a few well-defined snow squalls by late morning or early afternoon.

The most intense squall is projected to form off the southeastern shoreline of Lake Huron, extending from Port Franks through Strathroy and into the west end of London. Additional streamers could impact areas further inland and along the eastern Lake Huron shoreline, stretching from Kincardine down to Grand Bend.

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A separate squall will develop off Georgian Bay, spanning from Collingwood to Shelburne. Forecast models differ on the intensity of this squall, with some suggesting it could push far inland, potentially reaching parts of the Greater Toronto Area (GTA) just in time for the evening commute.

This scenario could bring a heavy burst of snow to the Hwy 400 corridor between Bradford and Vaughan, possibly extending to Mississauga and even the western parts of Toronto.

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The primary concern with this event is that the squalls are unlikely to shift much throughout the day. Instead, they could remain stationary for over 12 hours, beginning Thursday morning and continuing into the late evening.

As seen in Muskoka over the weekend, stationary squalls can produce extreme snowfall rates of 10–15 cm per hour, quickly overwhelming plowing operations and making travel nearly impossible as highways are buried in snow.

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Travel is strongly discouraged along the Lake Huron shoreline, particularly on Hwy 402 between London and Wyoming, during the day on Thursday and into the evening. Blizzard-like conditions, combined with rapid snowfall accumulation, will create dangerous and potentially life-threatening travel conditions.

The Georgian Bay squall is expected to diminish just after midnight, while the Lake Huron squall will gradually lift north of London during the pre-dawn hours on Friday. Additional lake effect snow is possible east of Lake Huron and Georgian Bay on Friday, though it remains unclear whether it will organize into significant squalls. We will provide updates in a separate forecast if substantial accumulation seems likely.

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The most intense snowfall is expected to target a small area west of London, including Parkhill, Ailsa Craig, and Strathroy, where totals could exceed 50 cm and potentially reach 75 cm. It’s important to note that these higher totals will be very localized, as the squall is forecast to be quite narrow. The exact location of the heaviest accumulation will depend on where the squall sets up.

While the City of London is likely to avoid the worst of the snowfall, it isn’t entirely in the clear. The city’s west end could see totals ranging from 25 to 50 cm. A slight eastward shift in the squall could place London directly in its path, significantly increasing snowfall totals for the area.

Lower amounts are expected in London’s east end, which is likely to see between 10 and 20 cm. St. Thomas could also be affected, with snowfall potentially reaching 20–30 cm depending on how far inland the squall extends.

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Other communities along the southeastern shoreline of Lake Huron, including Grand Bend, Lucan, Exeter, Clinton, and Goderich, are projected to receive 25–50 cm by the time the squalls diminish on Friday morning.

As is typical with snow squalls, snowfall gradients will be extremely sharp, and accumulation will drop off quickly outside the most affected areas. Locations such as Kincardine, Listowel, and Mitchell can expect totals of around 10–20 cm.

The Georgian Bay squall is anticipated to be less intense than its Lake Huron counterpart. Accumulations of 15–25 cm are expected for areas like Collingwood and Shelburne. If the squall extends into parts of the GTA, it could bring a quick 5–10 cm of snow, primarily affecting Brampton, Mississauga, and other areas in the western GTA.

Less than 5cm is expected for the rest of Southern Ontario.

Alberta Clipper to Bring a Snowy Blast to Southern Ontario on Wednesday With Up to 20cm Possible; Snowbelt Region Could See Up to 50cm

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The snowy landscape across Southern Ontario is quickly transforming as a multi-day snow squall event has blanketed parts of the snowbelt regions with over 100 cm of snow.

While the intense accumulation has primarily impacted areas around Lake Huron and Georgian Bay, the rest of Southern Ontario will soon have their turn as a weather system moves into the region on Wednesday.

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This system-related snowfall will likely combine with lake enhancement and embedded snow squalls, resulting in higher accumulations in the snowbelt areas that are still digging out from the weekend’s relentless snowfall.

By Thursday morning, some snowbelt regions could see an additional 30-50 cm of snow. Meanwhile, a general 5-15 cm of snow is expected across much of Southern Ontario, including parts of the Greater Toronto Area (GTA), which has experienced minimal snowfall so far this season.

The Alberta clipper responsible for this system began pushing into Northwestern Ontario from Manitoba on Tuesday afternoon. Moderate to heavy snow will continue spreading across Northern Ontario through the evening and overnight.

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In Northern Ontario, we expected the highest snowfall totals to be found east of Lake Superior stretching from Wawa down to Sault Ste. Marie. Snowfall totals of between 30 to 50cm are possible thanks to the system-related snowfall and snow squalls off Lake Superior.

Other areas around the Georgian Bay shoreline extending into Sudbury could be looking at around 20cm of snowfall accumulation. This will also be the case south of Lake Nipigon which could see some lake enhancement between Thunder Bay and Geardton.

The rest of Northeastern Ontario is looking at around 10 to 15cm with locally up to 20cm. Less than 10cm is expected for Northwestern Ontario including Thunder Bay.

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Ahead of the system, lake effect snow has already started to intensify, beginning with Lake Superior on Tuesday afternoon. By Tuesday evening, snow squalls are expected to organize off Lake Huron and Georgian Bay, primarily targeting the Bruce Peninsula and areas northeast of Georgian Bay, such as Parry Sound, Britt, and North Bay. These snow squalls are likely to persist through the night into Wednesday morning.

Additional lake effect snow could develop off Lake Erie and Lake Ontario during the early morning hours of Wednesday, potentially drifting into the southern Niagara region and Prince Edward County. While this activity may cause reduced visibility and locally heavy snowfall, the squalls are not expected to remain stationary for long, limiting overall accumulation.

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As the system reaches Southern Ontario around sunrise on Wednesday, the existing lake effect snow bands are expected to merge with the system’s light to moderate snowfall. This merging could enhance snow totals, particularly off the northern shorelines of Lake Erie and Lake Ontario. Narrow bands of heavy snow could stretch across the Niagara region and into parts of Central and Eastern Ontario, leading to significant variations in snowfall accumulations.

Snow totals will likely vary substantially due to localized banding caused by lake enhancement. Some areas may see only 5 cm, while nearby locations could receive 15-20 cm, depending on where the snow bands develop.

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Another key factor with this system will be strong wind gusts, ranging from 50-70 km/h across Southern Ontario, beginning Wednesday morning and continuing throughout the day. These winds, combined with steady snowfall, could create blowing snow and reduced visibility, making travel hazardous. With this being the first significant snowfall event of the season outside the snowbelt, drivers are urged to exercise caution.

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While the system is expected to exit Southern Ontario by late Wednesday, snow squall activity will persist off Lake Huron and Georgian Bay. An intense squall is projected to develop off Georgian Bay late Wednesday evening, stretching inland toward Midland, Orillia, and Gravenhurst, and continuing into the early hours of Thursday.

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By Thursday morning, shifting winds will push the Georgian Bay squall southward toward Collingwood and Angus. This squall may extend far inland at times, impacting the Highway 400 corridor between Vaughan and Barrie, as well as parts of the northern GTA. Meanwhile, a Lake Huron squall is anticipated to stretch from Goderich through Grand Bend and into the London area.

Significant snowfall could occur on Thursday if these squalls remain stationary for an extended period. Current models suggest they may not weaken until late Thursday night or early Friday morning, potentially producing intense snowfall rates for over 24 hours.

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Regarding snowfall totals, the uneven distribution caused by lake enhancement means localized accumulations will vary widely. The highest confidence lies in regions northeast of Georgian Bay, including Parry Sound, Sundridge, Britt, and North Bay, where 30-50 cm of snow is expected, with localized amounts possibly exceeding those totals due to snow squalls.

Surrounding areas, such as Muskoka and Orillia, could see 20-30 cm of snow by Thursday morning, accounting for system snow, lake enhancement, and snow squall activity. Similarly, areas east of Lake Huron could see totals ranging from 20-30 cm.

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In Central and Eastern Ontario, widespread snowfall is likely to range from 10-15 cm, except for the Ottawa Valley, where accumulations may be closer to 5 cm. Lake enhancement could push some areas along the northern shorelines of Lake Ontario and Prince Edward County closer to 20 cm.

For regions such as Kitchener, Woodstock, Guelph, and Barrie, snowfall totals are projected to reach 10-15 cm. However, variability due to lake enhancement may result in some areas seeing lower amounts. The GTA is expected to receive closer to 5 cm, while the Niagara region could accumulate 5-10 cm, with localized heavier bands of snow influenced by Lake Erie.

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In Deep Southwestern Ontario, snowfall amounts will decrease westward, with London forecasted to receive around 10 cm. Further southwest, including Sarnia, Windsor, and Chatham, totals are expected to remain under 5 cm.

It’s important to note that these totals do not account for the snow squalls expected to impact areas southeast of Lake Huron and Georgian Bay beginning Thursday morning. High-resolution models are still refining the locations of these squalls, but additional accumulations of 30-50 cm are possible in affected areas. Stay tuned for a detailed update in a separate forecast.

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Snow Squalls Continue to Paralyze Ontario’s Snowbelt With Another 25-50cm of Snow by Monday

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It may have been a slow start to the winter season across Southern Ontario, but November is certainly ending with a bang. Above-average lake temperatures have fueled intense lake-effect snow squalls that have pummeled the snowbelt regions over the past few days.

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As of Saturday evening, some of the hardest-hit areas, including Bracebridge, Gravenhurst, and Hanover, have reported snowfall totals ranging from 50 to 100 cm, with localized pockets even exceeding the 100 cm mark! This has led to massive issues on the roads as dozens of drivers were left stranded on Hwy 11 south of Gravenhurst due to extreme snowfall accumulation.

But the snowy barrage is far from over for these regions. By the time the squalls wind down late Monday, an additional 25 to 50 cm of snow could accumulate around areas east of Lake Huron and Georgian Bay.

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Currently, intense snow squall activity is ongoing east of both lakes, with a focus on the Bala-to-Bracebridge corridor and the Tiverton-to-Walkerton stretch. These squalls are expected to remain mostly stationary overnight, with snowfall rates reaching 5 to 10 cm per hour. This could add another 25 to 50 cm of snow in already heavily affected areas by Sunday morning.

By Sunday morning, a shift in wind direction is anticipated, pushing the squalls further south. The Georgian Bay squall will likely bring a quick but intense blast of snow to Midland, Orillia, and Barrie. Meanwhile, the squall near Hanover is expected to dissipate by late morning, only to be replaced by a more robust squall moving in from the north, targeting Owen Sound and Kincardine.

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This northern squall could stretch far enough inland to reach areas like Orangeville and perhaps even the Greater Toronto Area (GTA) by mid-afternoon. Although it won't last long enough to produce significant accumulation, it could lead to a sudden reduction in visibility and a quick 2 to 5 cm of snow. Similarly, Kitchener and Guelph may experience a few hours of heavy snow as the squall moves through.

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By Sunday evening, the squalls are expected to settle southeast of Georgian Bay and Lake Huron. Collingwood and Meaford are likely to find themselves in the crosshairs of the Georgian Bay squall, while the Lake Huron squall will stretch from Goderich along the shoreline to Grand Bend and inland towards areas north of London.

According to the latest model data, the Georgian Bay squall may remain closer to the shoreline, potentially sparing Barrie and the Hwy 400 corridor from the heaviest snow.

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However, London might not be as fortunate. The Lake Huron squall could extend into the city at times during the overnight hours and into early Monday. That said, the most intense snowfall rates are expected to stay north of London, impacting areas like Exeter, St. Marys, and Stratford.

Snow squall activity will persist throughout Monday and possibly into the overnight hours before tapering off late Tuesday morning. This will coincide with the arrival of a system from the west that could bring more widespread snowfall to parts of Southern Ontario. Details on that system will be shared in a separate forecast.

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As is typical with snow squalls, snowfall totals will vary significantly depending on where the squalls settle. There is high confidence that regions in Muskoka and along much of the eastern Lake Huron shoreline will see an additional 25 to 50 cm of snow on top of what has already fallen.

Northwest of London, models indicate the Lake Huron squall could stall over the area from Sunday evening through Tuesday morning, potentially leading to localized totals exceeding 50 cm. Confidence in this scenario remains low, so we’ve held off from including it in our snowfall map for now.

The City of London is forecast to receive 15 to 25 cm of snow from the southern tip of the Lake Huron squall. However, there is potential for slightly higher totals depending on how far the squall extends inland.

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The southern shoreline of Georgian Bay, including Collingwood and Meaford, is expected to see 25 to 50 cm of snow, with higher amounts likely in elevated areas such as Blue Mountain—great news for ski enthusiasts!

Simcoe County, including Barrie and Orillia, is forecast to receive lesser amounts, with 5 to 15 cm (possibly up to 20 cm) expected during the morning and afternoon hours on Sunday. Kitchener and Woodstock could also see 5 to 10 cm of snow from the Lake Huron squall.

Outside these core regions, snowfall will be minimal, with most areas receiving less than 5 cm. We are keeping an eye on the southern Niagara region and Prince Edward County, which could potentially be grazed by snow squall activity that is currently expected to remain south of the border. If it does drift north, localized totals of 5 to 10 cm could develop in areas like Fort Erie, Port Colborne, and Picton.

UPDATE: Squalls on Track to Bury Parts of Ontario’s Snowbelt in Up to 100cm of Snow by Saturday

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Confidence remains high for a very impactful snow squall event, which began east of Georgian Bay and Lake Huron Thursday evening. By the end of Saturday, some parts of the snowbelt region could be digging out of up to 50 to 100cm of snow!

Intense snow squall activity is expected to persist throughout Friday, with two primary squalls forming off Georgian Bay. The southern squall looks to settle between Honey Harbour and MacTier, extending inland toward the Highway 11 corridor from Washago to Bracebridge. This squall may reach as far inland as Haliburton and potentially Bancroft at times.

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The second squall is projected to stretch across the northern tip of the Bruce Peninsula, coming onshore near Parry Sound. Unlike the southern squall, this one may not push as far inland, meaning Huntsville could see lighter impacts compared to areas like Bracebridge and Gravenhurst.

Snow squalls will also persist east of Lake Huron, with the most significant activity setting up just south of Hanover. Higher totals inland can be attributed to colder temperatures in elevated areas, where snow will accumulate more efficiently, compared to the slightly above-freezing conditions closer to the shoreline.

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As Friday progresses, models suggest a brief wind shift by the evening, potentially driving the Georgian Bay squall south of Muskoka and into parts of northern Simcoe County.

There is some uncertainty about how far south this squall will drift, but most models suggest it will impact Midland, areas just north of Orillia, and into Rama. Within Orillia, accumulation could vary significantly, with lower totals in the south and much higher amounts in the north, reflecting the sharp gradient shown on our map.

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By Saturday morning, the squall is expected to shift back north, realigning across the Parry Sound and Muskoka region. However, this time, it may consolidate into a singular band stretching from Parry Sound into northern Muskoka. This could spare Gravenhurst and Bracebridge from heavy snowfall on a second day, while Huntsville might see more snow as the squall locks into place for much of Saturday.

IMPORTANT

To provide the most accurate information, we are now breaking the snowfall totals into two separate forecasts. This forecast covers Friday and Saturday, while a second forecast will address Sunday and Monday and will be released on Saturday.

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Our earlier forecast covered the entire four-day period and was intentionally broad to account for a wide range of possibilities. If the snowfall totals for your area are lower than what we initially predicted, it’s likely because your snow will fall later on Sunday or Monday.

As we’ve emphasized in previous updates, snow squalls are notoriously difficult to predict, with sharp gradients between areas of light snow and those with extreme accumulations.

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In terms of snowfall totals, localized amounts are likely to exceed 50 cm and may even approach 100 cm by the end of Saturday in areas like Parry Sound, Bracebridge, and Gravenhurst. Similar totals are possible for Tobermory and Hanover.

Owen Sound and Collingwood could also experience heavy snow from a Lake Huron streamer, with higher elevations aiding accumulation. These areas could see snowfall ranging from 25 to 50 cm in the most affected zones.

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Given the tight gradients, snowfall totals will decrease quickly as you move away from the primary snow squalls. Expect 15 to 30 cm across much of Grey-Bruce counties, northern Simcoe County, northern Kawartha Lakes, and Haliburton (excluding the heaviest-hit areas mentioned earlier).

For the rest of Southern Ontario, less than 5 cm is expected by the end of Saturday. However, regions like Barrie, Kitchener-Waterloo, and London could see some snowfall accumulation on Sunday and Monday as the winds shift late Saturday. So, if you’re hoping for snow in those areas, don’t give up yet!

Stay tuned for more updates, including our next detailed forecast on Saturday!

Intense Snow Squalls Could Bring Up to 50-100cm of Snow to Parts of Ontario This Weekend

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As we approach the first day of meteorological winter this Sunday, Ontario is preparing for a substantial blast of snow squalls that will make the season's arrival unmistakable. Beginning Thursday in Northern Ontario and Friday in Southern Ontario, persistent squalls are set to bury parts of the traditional snowbelt regions under as much as 50-100 cm of snow by the end of the weekend.

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The first extended period of cold air has settled over Ontario, combining with the warm waters of the Great Lakes to create ideal conditions for lake effect snow. Parry Sound and Muskoka got a preview of what’s to come, waking up to a winter wonderland on Wednesday morning. While the lake effect snow machine has temporarily quieted as winds shift, it’s poised to roar back to life over the next several days.

Snow squall activity will restart as early as Thursday morning in Northern Ontario, with an intense band developing off Lake Superior. This narrow and powerful squall is expected to affect the corridor between Wawa and Sault Ste. Marie through Thursday and into Friday. Snowfall rates could reach up to 5 cm per hour, and if the band lingers over one area for an extended time, accumulation will add up quickly.

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On Thursday, a system moving up the Northeastern U.S. will brush Southern Ontario. Most of the precipitation is expected to remain on the U.S. side of the border, but some areas in Ontario, including parts of the Greater Toronto Area (GTA) and Niagara region, could see light mixed precipitation or even their first flurries of the season. Little to no accumulation is expected, but slushy road conditions may develop for the Thursday morning commute.

As the system exits, winds will shift to a westerly or northwesterly direction late Thursday, triggering the return of lake-effect snow squalls. These squalls will intensify overnight and into Friday morning.

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Current models suggest the primary snow squall band will stretch across the Bruce Peninsula, move over Georgian Bay, and come ashore between Parry Sound and MacTier. Further inland, areas along the Hwy 11 corridor, including Huntsville and Gravenhurst, will also be affected.

Additional squalls are expected off Lake Huron, impacting regions such as Kincardine, Owen Sound, Hanover, Wingham, and Mount Forest.

One of the biggest concerns is the potential for squalls to remain stationary over specific areas for extended periods. Models suggest some regions could face 24-48 hours of relentless snowfall, with rates reaching 3-5 cm per hour from Friday morning to early Sunday.

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Road conditions are expected to deteriorate rapidly, and travel in affected areas should be avoided starting late Thursday. Near-zero visibility, combined with rapid snow accumulation and blowing snow, may create blizzard-like conditions. Improvements are unlikely until late in the weekend or even early next week.

By Sunday morning, a slight change in wind direction could push the Georgian Bay snow squalls southward into Simcoe County and the Kawartha Lakes region. Similarly, Lake Huron squalls may shift to target areas like Goderich, Stratford, and Listowel.

Lake Erie and Lake Ontario could also generate brief lake effect activity on Sunday, potentially impacting the Southern Niagara region, Prince Edward County, and Kingston.

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Environment Canada is also mentioning the potential for multiple rounds of lake-effect snow and squalls. They have highlighted areas east of Lake Huron and Georgian Bay in a ‘high’ weather threat for Friday and Saturday with locally up to 20-30cm of snow on both days.

There is also a ‘moderate’ weather threat on Sunday southeast of Lake Huron and Georgian Bay with locally up to 10-20cm. Combined, Environment Canada’s forecast is suggesting that snowfall totals could range from 50 to 80cm over those 3 days!

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Snow squalls are highly localized, often only a few dozen kilometres wide, meaning snowfall totals can vary dramatically over short distances. One area might receive 50+ cm, while another just down the road may see barely a dusting.

Because of this variability, we are focusing on general zones for now. Higher-resolution models will help refine the forecast as we approach the weekend, and updates will be provided accordingly.

Snowfall totals across the traditional snowbelt regions could be significant:

  • 50-100 cm: Areas east of Georgian Bay and Lake Huron, including Bracebridge, Gravenhurst, Huntsville, Parry Sound, Owen Sound, Kincardine, Goderich, and Hanover.

  • 25-50 cm: Surrounding regions, including the Bruce Peninsula, Collingwood, Midland, and Orillia. Totals will drop quickly further from the snowbelt.

  • 5-15 cm: Localized areas in the Southern Niagara region (e.g., Port Colborne and Fort Erie) and Kingston, mainly on Sunday, if lake effect activity drifts north of the border.

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For Northern Ontario, the corridor between Wawa and Sault Ste. Marie is expected to see snowfall totals between 50-100 cm from Thursday morning through late Sunday. Accumulations will taper off sharply as you move away from the Lake Superior shoreline.

Stay tuned for further updates in the coming days as we break down this dynamic weather event and provide more detailed forecast maps.

Winter Roars Into Ontario This Week With Freezing Rain Threat; Snow Squalls Could Dump Up to 50cm of Snow

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While winter has gotten off to a slow start across Southern Ontario, with many areas only seeing their first snowfall within the past week or two, it seems that change is on the way. November is shaping up to go out like a lion, as Mother Nature makes up for lost time.

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A significant pattern shift is expected to bring the threat of freezing rain late Monday across Central and Eastern Ontario. This will be followed by multiple weaker systems across the Great Lakes region and colder air flooding into the province.

That colder air will set the stage for what could become our first major snow squall event later this week and into the weekend. In some typical snowbelt areas, snowfall could be measured in feet (30+ cm) by this time next week!

Let’s break down what is shaping up to be a very dynamic and active forecast over the next five to seven days, starting with the freezing rain threat.

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Freezing Rain Risk: Monday into Tuesday

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A system is expected to move into Southwestern Ontario and the Golden Horseshoe beginning Monday afternoon. With temperatures forecasted to stay well above freezing in these areas, precipitation will fall as rain.

However, as the system moves northeast into Central and Eastern Ontario after midnight, it will encounter a stubborn layer of colder air near the surface. Temperatures hovering near or just below freezing may allow some of the rain to fall as freezing rain overnight into early Tuesday morning.

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There remains some uncertainty about how widespread this pocket of cold air will be. Higher-elevation areas of Central and Eastern Ontario, including Bancroft, Barry’s Bay, and Algonquin Park, are most likely to experience freezing rain. It’s also possible for freezing rain to extend westward to Muskoka and Parry Sound, and eastward into the Ottawa Valley, including the City of Ottawa.

For Bancroft, Barry’s Bay, and Algonquin Park, ice accretion totals could reach 2-4 mm by Tuesday morning, though any ice will quickly melt after sunrise as temperatures rise above freezing by late morning. In Muskoka and the Ottawa Valley, a thin layer of ice on untreated surfaces is possible, which could make for a slow Tuesday morning commute. There is a slight chance of school bus cancellations in affected areas.

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Northern Ontario: Heavy Snowfall Ahead

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Northern Ontario will experience heavy snow from this same system, as colder air dominates in the region. Light to moderate snowfall is expected to begin in Northwestern Ontario by early Monday afternoon, gradually spreading eastward into the evening and overnight.

Snow will continue across Northern Ontario throughout Tuesday, with the heaviest snowfall expected near the Quebec border in Northeastern Ontario. Snowfall will gradually ease later on Tuesday and into early Wednesday but could persist near James Bay in a zone extending from Hearst to Lansdowne House.

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Over three days, snowfall totals will generally range from 10 to 20 cm across Northern Ontario. Far Northern Ontario near James Bay could see totals exceeding 20 cm by Thursday, while lake-enhanced snowfall southeast of Lake Superior, including Sault Ste. Marie, could push totals closer to 30 cm.

Thunder Bay is expected to see slightly less snow, as the city may end up in a drier part of the system. Forecasts currently suggest snowfall amounts of 5 to 10 cm in this area.

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Southern Ontario: Cold Air and Lake Effect Snow

PRECIPITATION TYPE - MAP FROM WEATHERBELL

As the system moves out of Southern Ontario late Tuesday, a surge of cold air will follow in its wake. This will briefly activate the lake effect snow machine around Lake Huron and Georgian Bay beginning Tuesday evening and lasting into Wednesday.

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At this time, temperatures are expected to hover near the freezing mark, which could limit significant accumulation. The most likely target zone for this initial burst of lake effect snow includes areas east of Georgian Bay, such as Parry Sound, Huntsville, and Bracebridge. These areas could see 10-15 cm, with localized amounts of up to 20 cm by the time snow bands taper off Wednesday evening.

For higher elevations southeast of Owen Sound, including Hanover, Markdale, Shelburne, and Orangeville, up to 5-10 cm of snow is possible, as cooler temperatures in these areas will allow snow to accumulate more easily. Surrounding regions, including parts of the Greater Toronto Area, may see just a few light flurries.

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End of the Week: A Snow Squall Event Looms

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Lake effect snow will temporarily pause as another system slides through the Great Lakes region. However, this system appears to stay largely south of the border, bringing only a few flurries or light showers to areas near Lake Erie and the Golden Horseshoe early Thursday.

As we approach the weekend, Southern Ontario will see its coldest air of the season so far, with overnight lows plunging to several degrees below freezing across much of the province.

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A dominant westerly to northwesterly wind is expected to develop Friday and persist into the weekend. This setup will create ideal conditions for intense snow squalls off Lake Huron, Lake Superior, and Georgian Bay starting Friday afternoon and lasting through the weekend.

These snow squalls could bring significant snowfall totals, blowing snow, and near-zero visibility to localized areas in the snowbelt. Travel could become difficult or even dangerous in the hardest-hit regions.

Based on the current forecasted wind direction, regions including Kincardine, Owen Sound, Hanover, Midland, Oro, Orillia, and Gravenhurst are likely to see the heaviest impacts. This also extends up into Northern Ontario around the Lake Superior shoreline with Sault Ste. Marie in the bullseye. Some locations within this zone could receive up to 50 cm of snow by the end of the weekend.

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Snow Squall Uncertainty

It’s important to note that snow squalls are highly localized events, and not everyone will experience intense snowfall totals. One area may receive significant snow accumulations, while locations just a few kilometres away might see only a dusting.

Confidence is high that some sort of snow squall event will occur, but exact locations will depend on the finer details of wind direction and temperatures.

CREDIT: Environment CANADA

Environment Canada has also mentioned the potential for significant snow squalls later this week:

The first significant lake effect snow of the season is likely beginning Friday. This has the potential to be a highly disruptive and prolonged event for areas near Lake Huron, Georgian Bay and eastern Lake Superior. While confidence is medium to high that lake effect snow and blowing snow will occur, confidence in exact locations to be affected as well as snowfall accumulations is low. As is normally the case in these situations, snowfall amounts will be highly variable. Some areas may see well in excess of 50 cm by the end of the weekend. - Environment Canada

Stay tuned for updated forecasts in the coming days as higher-resolution models provide more details. We’ll refine the snow squall forecast and pinpoint areas most at risk.