Southern Ontario’s Never-Ending Winter Continues This Weekend as Squalls Threaten to Bring Up to 50cm of More Snow

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With a steady parade of system after system, along with lake effect snow in between, it’s certainly understandable that some parts of Southern Ontario are getting pretty fed up with all the snow. The snow continues to pile up, especially across the snowbelt regions!

It was only a few days ago that the Barrie area was slammed with intense lake effect snow, with up to 70cm reported in the hardest hit community of Angus. And that doesn’t even include what was already on the ground before this round of squalls moved through.

Regions east of Lake Huron, including Grey, Bruce, Huron and Perth counties, have also seen their fair share of snow so far this winter, with frequent lake effect events adding to an already deep snowpack.

Fortunately for snow lovers, and perhaps unfortunately for everyone else, the squalls are far from finished. The lakes remain wide open, and we are just getting into the heart of colder Arctic air. That combination will continue to provide plenty of fuel for additional rounds of lake effect snow in the coming weeks.

The next round of squalls is just around the corner, with activity expected to ramp up again as early as Saturday morning. The good news for areas that were recently hammered by the Georgian Bay squall, including Barrie and Wasaga Beach, is that you should catch a bit of a break this weekend. The bulk of the activity will focus farther north and west.

Those east of Lake Huron, including Huron, Bruce and Grey counties, are not as lucky. Lake effect snow off Lake Huron is expected to target these areas once again with repeated rounds of snow through the weekend.

This is shaping up to be a multi-day lake effect event, with squalls persisting through the weekend and possibly into Monday. Winds are expected to be somewhat unstable, which means the squalls will tend to drift around rather than remain locked over one specific area. Because of this, it’s unlikely we’ll see extreme localized totals like the 50 to 75cm that fell southwest of Barrie earlier this week.

That said, snowfall totals will still add up. The hardest hit areas, including Parry Sound, Bracebridge, Tobermory, Owen Sound, Hanover, Collingwood, Goderich and Grand Bend, can generally expect 25 to 40cm. Some pockets, particularly across Muskoka, could push closer to the 50cm mark.

PRECIP TYPE - MAP FROM WEATHERBELL

The event is expected to get underway early Saturday morning as a brief southwesterly wind develops. A weak system moving through the region will become enhanced by the lakes, producing short bursts of heavy snow.

This could impact areas northeast of Georgian Bay as well as regions northeast of Lake Erie and Lake Ontario. Places like Parry Sound, North Bay, Niagara and Kingston could see a quick 5 to 10cm early Saturday morning, along with near-zero visibility at times.

Hourly snowfall rates (cm) - MAP FROM WEATHERBELL

As that system exits, winds will become more westerly, shifting the focus back to Georgian Bay and Lake Huron through Saturday afternoon and evening.

Current model guidance shows a fairly potent and narrow band setting up near the northern tip of the Bruce Peninsula, stretching across Georgian Bay and coming inland near Port Carling and Bracebridge. Keep in mind that even small shifts in wind direction could push the heaviest snow several dozen kilometres north or south.

Very poor to hazardous driving conditions are expected along the Highway 400 and Highway 11 corridors in this area. Highway closures are not out of the question, especially given how quickly conditions can deteriorate.

Additionally, somewhat weaker bands are also expected to develop off Lake Huron, impacting the Owen Sound to Goderich corridor. There remains uncertainty regarding exactly where these bands will set up and whether they consolidate into a more dominant squall.

Hourly snowfall rates (cm) - MAP FROM WEATHERBELL

Later Saturday, a subtle wind shift will cause the main Georgian Bay squall affecting Muskoka to briefly drift south into Simcoe County. This could bring a short period of heavy snow overnight Saturday to Midland, Orillia and Barrie. Accumulation here should be limited, generally around 5 to 10cm, as the squall will be moving through fairly quickly.

A similar evolution will occur east of Lake Huron, with the squall drifting from Tobermory down through the Bruce Peninsula and into southern Bruce and Grey counties overnight. This activity will continue as the squall settles farther south and west of London under a more north-northwest flow.

PRECIP TYPE - MAP FROM WEATHERBELL

By Sunday morning, the strongest lake effect activity is expected to be found off Lake Huron, affecting the Grand Bend to London corridor. At this point, it appears the core of the squall should remain just west of London, impacting areas like Strathroy, though brief pushes into the city are still possible.

The Georgian Bay squall will temporarily weaken as winds become less favourable for a strong lake fetch. This should restrict activity mainly to shoreline areas near Meaford and Collingwood for a time.

Hourly snowfall rates (cm) - MAP FROM WEATHERBELL

That break will be short-lived. By Sunday evening, increasing winds will allow lake effect snow off Georgian Bay to intensify once again. Some models show moderate to heavy snow developing from Meaford through Collingwood and extending toward the Orangeville region overnight, before the lake effect machine is shut down by an approaching system on Monday morning.

Lake Huron squalls will continue through this time, remaining heavy at times across Huron County, Grand Bend and areas west of London. As with earlier periods, most of the heaviest snow should stay just to the west of the city.

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Because the squalls will be shifting around, snowfall will be more evenly distributed across a wider area. We aren’t expecting extremely high localized totals, but many communities will still share in the heavy snowfall. By the end of the weekend, most areas east of Lake Huron and Georgian Bay could see totals ranging from 25 to 50cm.

The usual lake effect disclaimer applies. Some locations will inevitably end up just outside the heaviest bands, but the contrast should be less dramatic this time since most snowbelt areas will be impacted at some point.

The main target zones include areas east of Georgian Bay, such as Parry Sound, Rosseau, Port Carling, Bracebridge and Port Sydney, along with much of Bruce, Grey, Huron and Middlesex counties east and southeast of Lake Huron. This includes communities like Tobermory, Wiarton, Lion’s Head, Owen Sound, Meaford, Collingwood, Flesherton, Hanover, Chatsworth, Port Elgin, Kincardine, Mildmay, Point Clark, Wingham, Goderich, Clinton, Exeter, Lucan, Grand Bend and Strathroy.

Snowfall totals will drop off quickly outside of these regions, as lake effect snow remains highly localized. However, as mentioned earlier, a brief 5 to 10cm is still possible Saturday morning for parts of Niagara and the Kingston area due to lake-enhanced snow from the passing system.

For the rest of Southern Ontario, expect around 2 to 5cm from that system on Saturday, with most locations likely closer to the lower end of that range outside of the snowbelt.

Barrie Area to Be Buried in Up to 40 to 75 cm of Snow on Thursday as Arctic Air Fuels Dangerous Snow Squalls

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Snowfall from the Alberta Clipper that slid through Southern Ontario earlier on Wednesday is beginning to taper off. The system has left its mark across the region with a widespread 10 to 20cm of snow in some areas, while others saw a slushy mix.

While the clipper may be done, the snowfall story is not. As the system pulls away, it ushers in a polar blast of cold air overnight on Wednesday. This air, combined with strong northwesterly winds, will kick the lake effect snow machine back into gear off Lake Huron and Georgian Bay.

Intense snow squalls across Simcoe, Huron and Perth counties throughout Thursday are likely to create dangerous conditions. Frigid wind chills paired with near-zero visibility will make travel extremely difficult and even life-threatening if you become stranded.

The Georgian Bay squall is expected to be particularly intense. A narrow corridor from Wasaga Beach through southwest Barrie, including Angus, Innisfil and into Bradford, may see the band lock in place for more than six hours. Snowfall rates could exceed 5cm per hour.

Localized totals around the Barrie area could approach 50 to 75cm in the hardest hit pocket. Some high resolution models even suggest 100cm is not completely off the table.

East of Lake Huron, activity will be persistent from Thursday morning through the evening. The lake effect here appears more spread out rather than focused on one specific pocket. The heaviest totals are expected across Huron and Perth counties, where up to 50cm is locally possible.

PRECIP TYPE - MAP FROM WEATHERBELL

As of Wednesday evening, we are already seeing some activity begin ramping up off the southeast shoreline of Lake Huron and Georgian Bay. This will continue to organize after midnight into the early hours of Thursday.

By early morning, we expect the most focused squalls to target the Goderich to London corridor off Lake Huron and the Collingwood to Bradford stretch off Georgian Bay.

Keep in mind, this is a rough idea from the models, and the exact placement can shift if the wind direction changes even slightly.

Hourly snowfall rates (cm) - MAP FROM WEATHERBELL

By the time the morning commute begins around 6 AM, snow squall activity will intensify as the Georgian Bay band becomes extremely narrow and focused. Some model runs have it stretching from Wasaga Beach through Angus and into the Innisfil to the Newmarket area.

There remains uncertainty in how much snow the City of Barrie itself will receive. The gradient between limited snow and a huge dumping will be very tight. The south and west ends are most likely to see major impacts, although it would not take much of a shift for the band to slide directly into the city.

The Lake Huron activity will begin to spread out with moderate snowfall covering much of Huron and Perth counties, including Goderich, Wingham, Stratford and Listowel. Because the band is more diffuse, there will not be one intense pocket as we expect with the Georgian Bay squall.

ESTIMATED WIND CHILL - MAP FROM WEATHERBELL

A major factor with this round of squalls that makes the situation more dangerous is the very cold wind chills. When you wake up Thursday, wind chills will make it feel like the -20s. Combined with squalls at the same time, the risk to anyone stranded on the roads increases significantly.

Aside from the cold creating hazards, it will also boost snowfall rates. Colder air produces drier, fluffier snow, which allows the same amount of moisture to create a larger volume of accumulation.

Hourly snowfall rates (cm) - MAP FROM WEATHERBELL

Little will change heading into the late morning as the Georgian Bay squall remains locked in place near the Barrie area. The band could edge far enough north to put the city core into the bullseye. Keswick may also be brought into the heavy snow as the band wobbles.

For the Lake Huron squall, the band may briefly become more focused as a single strong line cutting through Goderich and into Stratford and Woodstock. Depending on slight track shifts, Kitchener or Hamilton could also be affected at times.

Hourly snowfall rates (cm) - MAP FROM WEATHERBELL

Conditions are expected to deteriorate further into the afternoon. The Georgian Bay squall appears to strengthen with hourly snowfall rates easily exceeding 5cm and possibly pushing 10cm. At this point, the most intense pocket is shown just southwest of Barrie, with Angus being hit hardest.

The Lake Huron squall will also become more organized with an impressive fetch stretching all the way toward Lake Erie and impacting Woodstock and Norfolk.

Hourly snowfall rates (cm) - MAP FROM WEATHERBELL

There is significant concern for the Hwy 400 corridor during the afternoon and evening commute from just south of Barrie to roughly Aurora. This section of highway will likely become snow covered with road crews struggling to keep up with extreme snowfall rates. Combined with whiteout conditions, travel in this zone should be avoided unless absolutely necessary.

Hourly snowfall rates (cm) - MAP FROM WEATHERBELL

As we head into the evening and just past midnight, the squalls will retreat closer to the lakeshores as winds weaken and moisture supply cuts off. This will lead to activity tapering to lake effect flurries overnight into Friday morning.

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As always with snow squalls, snowfall forecasts should be taken with a large grain of salt. While models are in good agreement on placement and intensity, nothing is guaranteed as conditions need to align perfectly.

With that being said, we believe the hardest hit zone will be along the southeastern Georgian Bay shoreline from Wasaga Beach through Angus and into northern York Region. Barrie sits right on the edge but could easily end up inside the bullseye. Snowfall totals here are likely to exceed 40cm and may approach 75cm. Around Angus is where models show the strongest signal.

A tight gradient will set up with the north and east sides of Barrie, along with Keswick, Bradford and Collingwood, likely seeing 25 to 40cm of snow.

East of Lake Huron including Kincardine, Minto, Point Clark, Wingham, Listowel, Mitchell, Stratford, Exeter and Goderich, totals of 25 to 40cm are expected. Localized amounts up to 55cm are possible if a squall locks in place for several hours.

Totals of 15 to 25cm are possible for Midland and into central York Region including Newmarket and Aurora as well as Durham Region around Uxbridge. These areas will see occasional bursts of heavy snow near the edge of the main bands.

Southern Bruce and Grey counties along with Wellington County including Arthur and Oxford County may also see 15 to 25cm but totals depend on how far inland the bands extend.

Between 5 and 15cm is possible across the rest of York and Durham Region as well as northern Simcoe County including Orillia, Owen Sound, Shelburne, Fergus, Kitchener, Brantford and London. These locations sit farther from the core activity so most will see closer to 5cm with higher amounts only if a band stretches farther inland.

Less than 5cm is expected outside the snowbelt regions including Eastern Ontario, Deep Southwestern Ontario and the Golden Horseshoe.

Brief, Intense Snow Squalls Return to Southern Ontario’s Snowbelt on Thursday With Up to 20 to 50cm Expected

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Intense but brief snow squalls are expected to return to parts of the snowbelt region around Lake Huron and Georgian Bay early Thursday morning with the arrival of a blast of brisk Arctic air. These squalls have the potential to bring heavy snowfall and near-zero visibility in the hardest hit areas.

Conditions are certainly ripe for more extreme, long-lasting squalls; However, the latest model data suggests this round will be cut short as shifting winds prevent the bands from locking in place for any prolonged period of time.

Snow squalls developing off Lake Huron will follow a west-northwest flow with the most intense activity aimed at the northeastern shoreline, which includes much of Grey Bruce. Another band off Georgian Bay will have a less steady flow, making the Lake Huron squall the stronger and more focused of the two.

This band is expected to remain mostly stationary through much of the morning and possibly into the early afternoon before slowly weakening later in the day. Hazardous conditions are expected in this zone with complete whiteouts, blowing snow and rapid snowfall rates of 4 to 6cm per hour.

The hardest hit areas are likely to be around Port Elgin, Kincardine and Owen Sound where a band could set up early and barely move until the afternoon as winds ease and the squall dissipates. The reach of this band may stretch inland into parts of Grey County at times, including Meaford, Chatsworth, Flesherton and Hanover. Some areas could be digging out from significant totals by the end of the day.

Meanwhile, over Georgian Bay, shifting wind directions will make things much less predictable. The squall here will likely spread snowfall over a wider area rather than focusing on one region, mainly due to the flow swinging from westerly to northwesterly throughout the day.

It will likely begin with a westerly flow during the early morning, which would start the band in southern Muskoka, including MacTier, Bala, Bracebridge and Gravenhurst. It may also extend at times into southern Haliburton and northern Kawartha Lakes.

As winds turn more northwesterly, the band will slide down along the Hwy 400 and 11 corridor into northern Simcoe County, affecting Midland, Orillia and Washago. Travel in this region during the morning and early afternoon should be avoided if possible, as conditions will be quite poor.

There is still some uncertainty regarding the intensity of this Georgian Bay band, as shifting winds tend to weaken squalls and make them less organized. If it becomes even briefly stationary, that would likely be the period where snowfall intensifies.

How long the band can hold together before winds lock into a true northwest flow will determine totals for areas such as Barrie and the southern portions of Kawartha Lakes. By the early afternoon, the squall will have sunk into Wasaga, Oro and Barrie, but once the wind shift finalizes, the band will quickly lose its structure and begin to fizzle out.

If the squall lasts only into the mid-afternoon, Barrie may end up closer to 10cm. If it somehow holds into the evening, totals closer to 30cm would be possible.

All snow squall activity is expected to taper off by Thursday evening across Southern Ontario, although some light snow may linger overnight into Friday morning in areas closer to the lakes.

For Northern Ontario, snow squalls off the southeastern shoreline of Lake Superior will develop overnight and persist through much of Thursday. Sault Ste. Marie and the Wawa region may pick up 30 to 50cm by the end of the day. That lake effect activity is expected to weaken Thursday evening as a weak system shifts the wind direction.

Snowfall totals will vary widely due to ongoing uncertainty about the exact placement and duration of the bands. Confidence is highest that the Lake Huron squall will remain more focused compared to the Georgian Bay band.

As a result, the hotspot includes Port Elgin, Owen Sound, Hanover and Chatsworth, where 30 to 50cm is expected, with some models even hinting at localized pockets approaching 60cm.

The rest of Grey and Bruce counties are looking at 15 to 30cm, although totals may vary significantly depending on how far inland the squall extends and whether it drifts south into northern Huron and Perth counties.

Areas farther south and inland, including the rest of Huron and Perth counties, Wellington, Dufferin and Collingwood can expect around 5 to 15cm, but there is still a chance for much lower amounts if the band does not stretch that far.

A large zone along the Hwy 400 and 11 corridor from MacTier and Gravenhurst in the north to Barrie in the south, including Midland, Washago, Orillia and Wasaga, is expected to see the highest totals from the Georgian Bay squall.

At this point, 15 to 30cm appears likely, although localized totals up to 40cm are possible should the squall stall for any period of time. If that occurs, the most probable region for this is somewhere between Midland and Orillia.

The rest of Muskoka, Parry Sound, Haliburton, Kawartha Lakes and northern York and Durham regions can expect between 5 and 15cm, depending heavily on how far inland the Georgian Bay squall is able to stretch.

Elsewhere across Southern Ontario, less than 5cm is expected by the end of Thursday.

Dangerous Snow Squalls Target Southern Ontario’s Snowbelt Starting Thursday With Up to 75cm of Snow Possible

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Confidence continues to grow in what is shaping up to be a potentially dangerous snow squall event for regions east of Lake Huron and southeast of Georgian Bay as we wrap up the week.

Temperatures are expected to drop sharply overnight Wednesday, which will help kick the lake effect snow machine into gear as early as Thursday morning.

At first, the activity should be fairly limited. Scattered pockets of lake effect snow are expected to develop east of Lake Huron and Georgian Bay as a westerly wind pattern holds through the morning. Impacts will be minor at this stage, but this early activity will set the stage for a much more intense setup later in the day.

Rapid changes are expected by late Thursday morning and especially into the afternoon. This is when more organized squalls will begin to form.

The worst conditions are expected to develop late Thursday and last into Friday morning. A brisk northwesterly wind will allow narrow but powerful bands of snow to strengthen off both Lake Huron and Georgian Bay. These bands will be capable of producing snowfall rates near 5 to 10 cm per hour at times, along with near-zero visibility.

Travel will likely become extremely difficult through the hardest hit regions. Strong winds will create blowing snow and possibly even brief blizzard conditions. Road closures are possible, and anyone with non-essential travel plans should consider postponing. School bus cancellations appear likely for Friday, and there is even some potential for cancellations on Thursday, depending on how quickly conditions deteriorate.

The main snow squall activity is expected to taper off throughout the day on Friday, although some scattered bands could linger into Saturday. By the end of the day Friday, some areas east of Lake Huron, such as Goderich, Kincardine and Stratford, may be digging out from more than 40 cm of snow. Other parts of the snowbelt may see anywhere from 10 to 40 cm, depending on how close they are to the core of the activity.

PRECIP TYPE - MAP FROM WEATHERBELL

As mentioned earlier, Thursday morning will start with some light to moderate activity east of Lake Huron and Georgian Bay. This includes Grey Bruce, Parry Sound and Muskoka.

Impacts should be limited at first since the snow will be fairly light, but Environment Canada currently has a snow squall watch in effect for this entire region due to what will likely unfold later in the day.

Hourly snowfall rates (cm) - MAP FROM WEATHERBELL

Conditions will escalate quickly heading into the late morning and afternoon as scattered flurries begin organizing into more defined bands. We expect a fairly long squall to develop over Lake Huron, cross the Bruce Peninsula and come onshore east of Georgian Bay. This could bring a few hours of heavy snow to the Muskoka region.

Additional pockets of lake effect snow may also fire up further south off Lake Huron, affecting areas like Goderich, Hanover, Stratford and Kitchener.

Hourly snowfall rates (cm) - MAP FROM WEATHERBELL

That Georgian Bay squall is expected to gradually sink southward as the wind shifts from westerly to northwesterly. This will cause a swath of intense snow to drift across the Highway 11 and 400 corridor between Bracebridge and MacTier, down toward Barrie.

A few hours of rapid whiteout conditions are possible during the afternoon. Even though temperatures may hover near the freezing mark, which slows accumulation, visibility will still be extremely poor and blowing snow will create dangerous travel conditions.

Hourly snowfall rates (cm) - MAP FROM WEATHERBELL

Conditions will worsen significantly into the evening as the squall drifts far enough south to draw its full moisture supply from Lake Huron instead of Georgian Bay. This new orientation will allow the band to tap into a longer stretch of open water, which increases its intensity.

At this point, several intense bands could stretch inland between Kincardine and Goderich and reach as far east as Kitchener and even the western GTA at times.

There is still some uncertainty in how these bands will align. A slight shift in wind direction can cause a squall to lock in place further north or drift south. This will dramatically affect who sees the heaviest snow. Regardless, conditions will be poor even in areas that are not directly underneath a streamer due to the blowing snow.

Within the core of the squalls, snowfall rates of 5 to 10 cm per hour will be possible. Thundersnow and lightning cannot be ruled out, given the strength of the setup.

Georgian Bay will see a brief lull with lighter pockets of snow affecting the South Muskoka to Simcoe County corridor. This break will be short-lived as winds shift yet again heading into the overnight hours.

Hourly snowfall rates (cm) - MAP FROM WEATHERBELL

The most dangerous conditions are likely overnight Thursday into Friday morning. A very intense squall off Lake Huron is expected to set up somewhere between Goderich and Kincardine and stretch inland toward regions between Kitchener and London.

There is still uncertainty about the exact placement. Even a tiny shift in wind direction could pin this band farther north or push it farther south. At times, it may also extend into Hamilton and the Niagara region with quick bursts of heavy snow and whiteouts.

Southeast of Georgian Bay, more organized bands are likely to develop from Barrie into Kawartha Lakes. Some of this activity may also clip the northern GTA, including York and Durham. The Georgian Bay squall will likely be weaker than the Lake Huron band, but model trends have strengthened it slightly in the latest data. Peak snowfall rates will likely sit around 3 to 6 cm per hour in the strongest areas.

Temperatures will plunge well below freezing overnight which will help snow accumulate far more efficiently.

Most model data suggests that the lake effect bands will remain locked in place through Friday morning, although the intensity may gradually decrease during the afternoon as winds begin to ease. Snow squalls could continue into Saturday, but confidence drops for the weekend pattern since the bands may become more fragmented and less organized.

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As always with lake effect snow, exact totals are extremely difficult to predict. These events can produce huge differences over very short distances. One community could pick up 50 cm while another, only a few kilometres away, sees barely any accumulation.

Even with this uncertainty, the most consistent model signal points toward a high-impact zone east of Lake Huron, picking up a general 40 to 75 cm of snow by Friday evening. This includes Goderich, Point Clark, Kincardine, Mildmay, Wingham, Clinton, Mitchell, Listowel and Stratford.

Localized totals near 100 cm cannot be ruled out, although these would be isolated pockets rather than widespread amounts.

A wider zone east of Lake Huron that stretches into the Kitchener area has the potential to see 20 to 40 cm of snowfall accumulation.

For Georgian Bay, the squall should be weaker than the Lake Huron band. We are going with 20 to 40 cm for regions like Collingwood, Wasaga Beach, Midland, Orillia, Barrie, Innisfil, Angus and Keswick. This may end up being a slight overestimate if the squall fails to organize as we saw in the last event, which significantly underperformed.

Muskoka, Parry Sound, Kawartha Lakes and parts of the eastern GTA may see 10 to 20 cm depending on how far the bands push inland.

Less than 10 cm is expected for the rest of Southern Ontario, including Eastern Ontario, the Golden Horseshoe and deep Southwestern Ontario, since they will be far enough removed from the main lake effect activity.

Winter Storm Targets Northern Ontario This Week as Intense Snow Squalls Line Up for Southern Ontario Starting Thursday

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A powerful system will sweep through the Great Lakes region this week, bringing a major winter storm to Northern Ontario and setting the stage for a significant snow squall event across Southern Ontario later in the week.

Across Northern Ontario, snowfall will begin to move into regions east of Lake Superior by late Tuesday. Light snow will start from Wawa through Timmins, gradually expanding north and west. Through the overnight hours into Wednesday morning, the system will push into Thunder Bay, Kapuskasing and surrounding communities.

The worst conditions are expected throughout the day on Wednesday. Winds will gust between 40 and 60 km/h, and when combined with heavy snowfall rates, visibility will deteriorate quickly. Blowing snow will be widespread across Northeastern Ontario and conditions may even reach blizzard levels at times.

Treacherous travel conditions will continue into Wednesday night and persist through Thursday morning as the storm deepens. Snowfall intensity will gradually ease later on Thursday, but steady snow will continue as the system stalls over Quebec. This will push long lasting bands of precipitation back into Northeastern Ontario, keeping snow going until early Friday morning.

By the time the storm fully exits, a wide swath of Northeastern Ontario is expected to receive 20 to 50 cm of snow, with localized totals possibly exceeding that. The heaviest totals are expected from Marathon through Kapuskasing, Cochrane, Timmins, and Temiskaming Shores, Wawa, Hearst and Chapleau. Snowfall totals here will range from 30 to 50cm with possibly as much as 60cm in localized pockets.

While Northern Ontario deals with the winter storm, Southern Ontario will be on the warm side of the system on Tuesday and Wednesday. Many areas will flirt with the double digits, especially in Southwestern Ontario. Scattered showers will develop early Tuesday with light rainfall amounts of roughly 5 to 10 mm.

By late Wednesday, though, the pattern begins to shift as cold air wraps in behind the departing system. Temperatures will drop quickly, and any lingering precipitation will change to wet snow by Wednesday evening.

This colder air will set the stage for lake effect snow to fire up. With a westerly wind overnight on Wednesday, snow squalls may begin to develop off Lake Huron and Georgian Bay.

These early bands could bring bursts of heavy snow to Grey Bruce, Parry Sound and Muskoka through Thursday afternoon, although the exact intensity remains uncertain as the higher resolution models are just entering range and showing stronger signals than the medium range guidance.

By late Thursday, winds will shift to a northwest flow. Temperatures will drop further into the negatives and this will allow squalls to strengthen. The Georgian Bay band is expected to sink south into Simcoe County and then extend into Kawartha Lakes and Peterborough.

At the same time, the Lake Huron band will slide south into Huron County and stretch toward Kitchener and the western GTA. Some early guidance even hints that this band could link up with the flow off Lake Superior, which can enhance snowfall rates.

Heading into Friday, it is still too early to give precise band placement. Current thinking suggests the northwest flow will hold through much of the day before winds start easing over the weekend. If that happens, squalls could remain active for an extended period.

While details can still shift, we are beginning to narrow down regions with the highest risk of heavy snowfall starting Thursday morning and continuing into Friday evening. Squalls will shift around at times, so snowfall will not be constant, but those under the core of the bands could see snowfall rates approaching 5 to 10 cm per hour. It will not take long for the snow to accumulate.

At this stage, exact totals are not possible to predict for Southern Ontario. However, some regions could easily see 25 to 50 cm by Friday night, with the potential for higher localized totals once high-resolution data comes into range.

For Lake Huron, our current focus areas include Kincardine, Goderich, Hanover, Kitchener, Hamilton and Orangeville.

For Georgian Bay, our primary targets include Midland, Barrie, Gravenhurst, Bracebridge, Orillia, Kawartha Lakes and Peterborough.

Anyone living in or near these regions should be prepared for dangerous travel conditions beginning Thursday. School bus cancellations are likely for some regions, and road closures are possible if squalls remain intense or stationary.

Snow Squalls Take Aim at London, Barrie and Northern GTA on Sunday With Up to 25-50cm of Snow Possible

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We enjoyed a brief break from the wintry weather on Saturday as temperatures soared into the double digits across much of Southern Ontario. The exception was Eastern Ontario, where the Ottawa Valley dealt with hours of freezing rain.

But that warm spell is going to be short-lived. Cooler air returns overnight into Sunday, and temperatures will slide back below the freezing mark. Once that happens, the lake effect snow machine will fire up again for the next couple of days.

And no, it isn’t déjà vu. The target zone for this round of squalls will look very similar to last week’s event, but the focus shifts slightly east. That puts areas like London, Barrie and even the Northern GTA, including York Region, in line to be hit hard.

By the time the squalls wind down on Monday, the hardest hit spots could be digging out from more than 25cm, with the potential for very localized pockets of 50cm.

PRECIP TYPE - MAP FROM WEATHERBELL

We expect the snow squall activity to begin ramping up late Sunday morning. As temperatures fall, lake effect rain bands will flip over to snow off the southeast shoreline of Lake Huron and Georgian Bay.

While the changeover happens in the morning, ground temperatures may stay just above freezing for several hours. This means the first few hours of snow could melt on contact. Accumulation will start later in the day once temperatures reach the freezing mark.

Even before the snow begins to stick, visibility will drop quickly. Those in the affected areas should expect sudden whiteouts and dangerous driving conditions.

Hourly snowfall rate (cm) - MAP FROM WEATHERBELL

By the dinner hour, the squalls will become much more organized. Snowfall rates from the Lake Huron band could rise to 5cm per hour. This main band is expected to extend from Lake Huron through Goderich and southern Huron County into the London region.

Additional squall activity will form southeast of Georgian Bay, running from the shoreline through Barrie and Angus and into Newmarket and Durham. This band looks weaker than the Lake Huron squall at first, but could still deliver rates of 2 to 4cm per hour.

Hourly snowfall rate (cm) - MAP FROM WEATHERBELL

The worst conditions are likely around midnight. The Lake Huron band is expected to lock onto London, bringing intense snow and rapid accumulation of 6 to 8cm per hour.

The Georgian Bay squall will also strengthen, sliding south of Barrie and focusing on Angus, Bradford and Newmarket. Some signals show it reaching into the Eastern GTA, including Scarborough, Ajax and Oshawa.

These squalls should remain mostly stationary overnight, although minor drifting is possible. As temperatures fall several degrees below freezing, expect snow to pile up quickly.

Hourly snowfall rate (cm) - MAP FROM WEATHERBELL

By mid-morning Monday, the bands will begin to weaken as winds shift more westerly. Some lake effect flurries could linger east of Lake Huron into Grey Bruce, but they are not expected to be very organized. Everything should taper off by late Monday.

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Snow squall forecasting always comes with big caveats. The bands are extremely narrow, which means the difference between 50cm and almost nothing can be only a few dozen kilometres.

This is why we provide a broad range. They help capture that uncertainty, but they are not a guarantee. With this event, the bands appear very intense but also very narrow, which means gradients will be sharp.

Based on the latest data, we expect the hardest hit areas from the Lake Huron squall to include Goderich, Clinton, Lucan, Exeter, Mitchell and London. Snowfall totals here could range from 25 to 50cm, with the chance that someone ends up over 50cm in a very localized spot.

Surrounding regions, including Grand Bend, Tillsonburg, Stratford, Wingham, and Point Clark, could see 15 to 25cm.

Further east into Grey Bruce and Dufferin County, we are expecting 5 to 15cm mainly on Monday as the lake effect shifts northward.

The Georgian Bay band looks even narrower than the Lake Huron band. A small corridor stretching from Collingwood through Angus and into Innisfil could see 25 to 35cm, with a chance of 50cm if the band really intensifies.

The City of Barrie is right on the edge. A small shift north or south would bring very different results. For now, the highest totals look likely in the south end of the city with 15 to 30cm. The north end may be closer to 10 to 20cm.

Substantial totals may also extend into the Northern GTA, including Bradford, Newmarket and Aurora. Totals along the Highway 400 and 404 corridor could range from 15 to 30cm.

Across the east end of Toronto and Durham, including Ajax, Pickering and Oshawa, occasional heavy bursts may bring 5 to 10cm.

The rest of Southern Ontario should see less than 5cm of snow by Monday from the lake effect.

All the Seasons in One Weekend for Southern Ontario as Freezing Rain, Thunderstorms and Snow Squalls Line Up

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There is really only one way to describe what November has been like across Southern Ontario when it comes to the weather: a roller coaster.

Last weekend brought our first widespread snowfall event of the season. That was quickly followed by intense snow squalls that buried parts of the Lake Huron shoreline with more than 50 cm of snow early this week.

That seasonal whiplash continues this weekend as a clear battle sets up between cold, wintery air and much milder fall-like conditions. Eastern Ontario, especially around the Ottawa Valley, will stay on the cold side with a risk of prolonged freezing rain throughout the day on Saturday.

Southwestern Ontario and the Golden Horseshoe will see a completely different story. Temperatures are set to rise into the double digits, and there is even a risk of thunderstorms on Saturday. Some of the warmest pockets around Windsor could briefly flirt with the 20s for a few hours.

By late Saturday, a sharp cold front will sweep through the region. This will send temperatures plunging again heading into Sunday, settling the battle in favour of the colder air. As this cold push arrives, the lake effect snow machine is expected to roar back to life over both Georgian Bay and Lake Huron.

TEMPERATURE - MAP FROM WEATHERBELL

We expect a frosty start to Saturday morning for most of Southern Ontario. Deep Southwestern Ontario will be the main exception as milder air starts to slide in early. Most areas should wake up close to the freezing mark. Deep Southwestern Ontario will already be climbing through the mid single digits.

By noon, Deep Southwestern Ontario should reach the double digits. Further northeast into the rest of Southwestern Ontario, the Golden Horseshoe and parts of Central Ontario, temperatures will range from the low to mid single digits. The Ottawa Valley will remain near the freezing mark well into the afternoon as the surge of mild air stalls just to the southwest.

PRECIP TYPE - MAP FROM WEATHERBELL

A developing system will start to spread heavy precipitation into Southern Ontario late Saturday morning or early afternoon. For most areas, temperatures will be warm enough for rain to be the dominant precipitation type. There’s even the risk of a thunderstorm!

Over the Ottawa Valley, however, we expect patchy freezing rain to form as temperatures linger stubbornly near the freezing mark.

Model guidance is not fully aligned on how warm the air will get in that region. Even a small shift of one or two degrees will change how long the freezing rain lasts and how much ice is able to accrete. This is one of the key uncertainties for Saturday.

TEMPERATURE - MAP FROM WEATHERBELL

Through Saturday evening, temperatures will continue climbing across much of Southwestern Ontario. Cities like London, Kitchener and Hamilton are expected to reach the double digits.

One important note is that daytime highs in many areas will actually be reached late in the evening instead of during the normal warmest part of the day!

Meanwhile, that pocket of near-freezing air over the Ottawa Valley is expected to hold on into the evening, which could allow several more hours of freezing rain.

As the system pulls east overnight Saturday, colder air will sweep in behind it. Temperatures will tumble through Sunday morning, switching any lingering precipitation to wet flurries by the time you wake up.

Hourly snowfall rate (cm) - MAP FROM WEATHERBELL

Behind the front, bands of lake effect snow will begin developing off Lake Huron and Georgian Bay early Sunday. These bands look messy and disorganized through much of the day, although localized totals of 10 to 20 cm are possible.

By late Sunday, more focused and intense squalls could form, especially around the London region off Lake Huron. These squalls may continue into Monday and could lead to localized 20+ cm totals.

We will have a more detailed, dedicated lake effect forecast released soon.

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When it comes to freezing rain accretion, there are several variables that could reduce or increase the amount of ice that actually builds up. This is a very temperature-sensitive event.

The heaviest icing is expected directly along the Quebec border and into the Hawkesbury region. Models show the potential for over 10 mm of freezing rain, but it is unclear how much of that will be able to stick. Heavy precipitation rates could limit the amount of ice that accumulates, and temperatures will sit very close to the freezing mark for much of the event.

Given all of this, we are going with a general 5 to 10 mm of icing for the hardest hit areas. If temperatures are even slightly warmer than expected, accretion could end up lower. This is certainly enough to lead to localized power outages and icy roads.

For the City of Ottawa, they sit right on the dividing line between lighter icing and heavy icing. We have placed them in the 2 to 5 mm range, but they could see locally up to 7 mm if the cold air becomes more stubborn than currently forecast.

Outside of the Ottawa Valley, expect minimal icing. Areas such as Bancroft, Cloyne, Perth, Carleton Place and Cornwall may see an hour or two of freezing rain before changing over to rain.

Snow Squalls Could Bury Parts of Southern Ontario’s Snowbelt in Up to 50cm of Snow Early This Week

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As much of Southern Ontario cleans up after our first widespread snowfall of the season, Mother Nature is showing no signs of slowing down. The lake effect snow machine is roaring to life over Lake Huron and Georgian Bay as we kick off the second week of November.

Snow squalls have already developed south of Lake Huron late Sunday evening and are expected to strengthen through the night. We’re also anticipating some squall development along the southern shoreline of Georgian Bay, which should organize by Monday afternoon or evening.

Two main regions are likely to see the most intense activity. The first stretches between Sarnia and London, while the second includes areas south of Georgian Bay from Blue Mountain and Meaford toward the west of Barrie. Both zones could see heavy snow squalls lasting through to Tuesday morning.

While snowfall totals will vary significantly across short distances, confidence is increasing that the hardest hit areas could see as much as 25 to 50cm by the time the squalls taper off on Tuesday. Localized pockets may even exceed 50cm, depending on where the heaviest bands set up.

Road conditions are expected to deteriorate quickly in these regions, with road and highway closures likely late Monday and into early Tuesday when the most intense squalls occur. Travel should be avoided unless absolutely necessary, as these bands can produce sudden whiteouts, making it nearly impossible to see the road ahead.

ESTIMATED AIR TEMPS AROUND 1.5KM ABOVE GROUND - MAP FROM WEATHERBELL

This setup is being fueled by a rare November appearance of a mini “Polar Vortex” which is pulling a blast of Arctic air into Southern Ontario. This cold air is flooding the upper levels of the atmosphere and setting the stage for intense lake effect activity.

To put it simply, when forecasters talk about 850mb temperatures, we’re referring to the air temperature roughly 1.5 kilometres above the ground. This level helps forecasters understand how cold the air mass is higher up in the atmosphere, which is critical for predicting lake effect snow.

Over the next few days, 850mb temperatures are expected to plunge into the negative teens. Lake effect snow forms when there’s a large temperature difference between the lake surface and the air above it, generally 13°C or greater. With upper air temperatures between -10°C and -15°C and lake temperatures still above 10°C, that difference is more than 20°C, creating ideal conditions for lake effect snow to thrive.

hourly snowfall rates (cm) - MAP FROM WEATHERBELL

As of midnight, snow has already developed off the southern shores of Lake Huron, impacting the Sarnia region. So far, the bands have been disorganized and spread out, but that’s expected to change by late Monday morning as a stronger, more focused squall forms somewhere between London and Sarnia.

While the exact placement remains uncertain, areas near Petrolia and Strathroy appear most likely to be in the direct path. The band will likely shift through the day as wind directions fluctuate, leading to varying snow intensities across nearby towns.

hourly snowfall rates (cm) - MAP FROM WEATHERBELL

By Monday evening, things will really start to ramp up. The main squall off Lake Huron will likely push inland, with a more northwesterly wind direction steering it toward Grand Bend, Goderich and potentially the western edges of London. It’s still unclear if the squall will reach directly into London or remain just outside the city, but if it does, the heaviest snowfall will likely fall on the west side.

Meanwhile, snow squalls are expected to organize over Georgian Bay with heavy snow bands developing between Owen Sound and Barrie. There’s still some disagreement among models, with some focusing more on Wasaga Beach and Barrie while others favour a southern shoreline setup.

An interesting twist could occur if these Georgian Bay bands extend far enough inland to be enhanced by Lake Ontario. In that case, snow could reach into the western GTA and even the Niagara region, leading to sudden bursts of heavy snow if everything aligns.

hourly snowfall rates (cm) - MAP FROM WEATHERBELL

This lake effect activity is expected to persist overnight and into Tuesday morning, though the Georgian Bay bands should weaken slightly around sunrise. West of London, however, heavy snow could continue well into Tuesday morning before breaking apart as conditions become less favourable later in the day.

As always with lake effect snow, totals are extremely difficult to pinpoint. These narrow bands can stay locked over one community for hours while completely missing another just a few kilometres away. One person may end up shovelling half a metre of snow while someone nearby barely sees a dusting.

That said, two areas consistently stand out across the latest model runs. One includes Lambton Shores, Grand Bend and Strathroy, while the other covers the southern Georgian Bay shoreline and higher terrain around Blue Mountain. These regions could see totals ranging from 25 to 50cm by Tuesday.

Surrounding communities such as Petrolia, Thamesville, St. Thomas and Lucan, along with Orangeville, Shelburne and Flesherton, are more likely to see 15 to 25cm.

Both London and Barrie sit right on the edge between lighter and heavier accumulations. We currently have them in the 5 to 15cm or 15 to 25cm zones, depending on how far east the snow squalls extend.

Finally, the Niagara region remains uncertain. If the Georgian Bay squalls stretch far enough inland and connect with Lake Ontario, parts of the region could pick up over 15cm of additional snow.

Outside of these snowbelt regions, impacts will be much less significant. A few flurries and brief bursts of snow are possible as the squalls wobble, but most areas outside the direct lake effect zones should remain relatively calm through Tuesday.

Snowy Sunday Sweeps Into Southern Ontario With First Widespread Snowfall of the Season

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While there has been a lot of uncertainty surrounding Southern Ontario’s first widespread snowfall event of the season, we’re finally starting to get a clearer picture of what will unfold on Sunday. After several model shifts over the past few days, the latest data is now coming into better alignment, giving us a more confident idea of how this system will behave.

A developing low-pressure system is expected to move in from the southwest late Saturday night, tracking across areas near Lake Erie through the day on Sunday. As it does, it will bring a broad swath of snow stretching from Windsor through the Golden Horseshoe and into Eastern Ontario. Snow is expected to last much of the day before gradually tapering off overnight.

At this stage, snowfall totals are expected to vary quite a bit across the region. The exact placement of the heaviest snow bands remains uncertain, and surface conditions will also play a big role. Since the ground is still relatively warm, some of the early snowfall may melt on contact before it can begin to accumulate, especially on roads and sidewalks.

In general, by Monday morning, snowfall totals are expected to range from around 5 to 10 cm across the Golden Horseshoe and into Eastern Ontario. Within those areas, localized pockets, particularly in Eastern Ontario, could pick up as much as 15 to 20 cm according to the latest model runs. Further north and west, across Central and Southwestern Ontario, amounts will be lower with less than 5 cm expected in most spots.

As the system departs, colder air will pour into Southern Ontario late Sunday night, sending temperatures well below freezing. Any slushy snow or water on roads, sidewalks, and driveways will freeze quickly overnight, which could create slick conditions for the Monday morning commute. Drivers should be prepared for icy patches, and there’s a decent chance of school bus cancellations in areas that see higher snowfall totals.

The colder air will also fire up the lake effect snow machine early next week. Model guidance suggests that an intense but narrow band of snow could form southeast of Lake Huron late Monday and continue into Tuesday. This could impact communities such as Grand Bend and London, where local snowfall totals could exceed 25 cm if the band remains stationary for an extended period.

PRECIP TYPE - MAP FROM WEATHERBELL

For timing, snow is expected to begin in Deep Southwestern Ontario shortly after midnight. Around Windsor and Chatham, it may even start as rain before transitioning to snow as temperatures drop closer to dawn.

PRECIP TYPE - MAP FROM WEATHERBELL

By late Sunday morning, the snow will have spread into the Golden Horseshoe, becoming heavier through the afternoon. In Eastern Ontario, snow will likely begin around Kingston early in the morning and reach the Ottawa area by midday.

hourly snowfall rates (cm) - MAP FROM WEATHERBELL

The heaviest snowfall rates across the Golden Horseshoe are expected from early to mid-afternoon, with some models projecting bursts of 2 to 4 cm per hour at times before tapering off toward the evening.

PRECIP TYPE - MAP FROM WEATHERBELL

For Eastern Ontario, steady snow will continue through the afternoon, peaking after dinner before easing into scattered flurries overnight. With that timing, school bus cancellations are quite possible for parts of Eastern Ontario on Monday.

There are also some indications that freezing rain or ice pellets may mix in along the international border Sunday evening. Areas such as Kingston, Brockville, and Cornwall are most at risk for this brief mix, which could add an extra layer of slickness to untreated surfaces.

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While there is still some disagreement among the models on exactly where the heaviest snow will fall, the general expectation remains 5 to 10 cm along the Golden Horseshoe and into Eastern Ontario, with some locally higher amounts near 15 cm.

We’ve outlined portions of Eastern Ontario and the higher elevations of the Niagara region on our map with a dotted zone, representing areas that could overachieve and see closer to 20 cm. However, that outcome is far from certain.

Keep in mind that this is the first significant snowfall of the season, and with ground temperatures still above freezing, actual accumulation could vary from one street to the next. Some areas may see a quick coating, while others struggle to hold the snow through the day, especially near the lakeshores.

Elsewhere, Southwestern Ontario and much of Central Ontario should see lighter amounts, generally only a few centimetres, with some localized areas possibly reaching up to 8 cm. Regions like Grey-Bruce and the northern parts of Central Ontario will likely miss out on the heaviest snow this time, but that may not last long as lake effect activity ramps up early next week.

PRECIP TYPE - MAP FROM WEATHERBELL

As higher-resolution models continue to come into range, we’re getting a clearer idea of what the first snow squall event of the season could look like. Current projections suggest activity will develop on Monday, with a more organized squall forming by the evening.

This band may set up somewhere between Grand Bend and Kettle Point, extending inland, likely just west of the City of London. Additional bands may also develop off Georgian Bay, impacting areas around Meaford and Collingwood.

Communities caught under these narrow squalls could see impressive snowfall totals, while just a few kilometers away, grass may still be visible. We’ll continue to refine the details as the event approaches and will have a more specific forecast on who could see the most snow closer to Monday.

Overall, this marks the true start of the winter season across Southern Ontario, with several systems and lake effect events lining up behind this one. It’s a good time to check that your winter tires are ready, snow shovels are handy, and morning routines include a few extra minutes to clear off your car. Winter is here to stay.

Snow Squalls Target the Grey-Bruce and Barrie Area Again With Locally Up to 50-100cm of Snow by Tuesday

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Snow squalls are expected to become well-organized and intensify by Monday morning. One squall off Lake Huron will target southern Grey-Bruce, with periods of intense snowfall throughout the day. Thundersnow is even a possibility in this area.

Another squall will develop off the southeast shoreline of Georgian Bay, impacting parts of southern Simcoe County, including Wasaga Beach, Barrie, Angus, Innisfil, and Keswick.

These squalls will persist into the afternoon, shifting at times. The northern squall could push into Wiarton, extend across Georgian Bay, and come onshore near Barrie. Meanwhile, the southern squall off Lake Huron will stretch from Kincardine to Hanover and could push far inland, periodically bringing heavy snow into parts of the GTA.

By Monday night into Tuesday morning, the Lake Huron squall is expected to stall over southern Grey-Bruce, potentially leading to extreme snowfall accumulation. Wherever this band locks in, snowfall rates could reach an incredible 5-10 cm per hour. Some models suggest this squall could remain in place until Tuesday evening, somewhere between Owen Sound and Hanover.

The Georgian Bay squall may weaken somewhat after midnight but could persist into Tuesday. All snow squall activity should fizzle out by early Wednesday morning.

Projected Snowfall Totals:

• Localized amounts near 100 cm are possible in Grey-Bruce, with hotspots likely near Port Elgin, Hanover, Chatsworth, and Flesherton. Not everyone in this zone will see these totals, but some areas will get buried.

• 25 to 50 cm is likely across the rest of Grey and Bruce counties, extending into northern Huron and Perth counties. This also includes areas along the southeastern shoreline of Georgian Bay, such as Collingwood, Wasaga Beach, and Barrie.

• 5 to 15 cm could extend into Kitchener, Guelph, Durham, and York as occasional bursts of heavy snow push outside the core snowbelt region.

• The GTA may see light snow at times but is unlikely to receive more than 5 cm over the next two days.

Aside from the snow, we’re starting the week on a much colder note. If you’re heading outside for Family Day, be sure to bundle up—wind chills in the -20s are expected on Monday.

Stay safe and stay warm!

Will It Ever End? Squalls Could Bring Up to Another 40cm of Snow by the End of Friday to Parts of Southern Ontario

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Are you enjoying winter yet, Ontario? ❄️ It feels like we've been stuck in an endless cycle of snow, with relentless snow squalls hammering the snowbelt regions.

Even outside the snowbelts, much of Southern Ontario joined in this week as a major winter storm dumped over 20 cm of snow across the region overnight into Thursday morning.

And the snowy pattern isn’t letting up anytime soon. More lake effect snow is on the way to end the week, followed by a potentially significant snowstorm this weekend.

The lake effect machine is expected to fire back up Thursday evening, becoming more organized overnight into Friday morning. Current indications suggest a strong snow squall will develop, targeting the Bruce Peninsula and stretching into parts of Simcoe County.

While squall activity should begin to wind down by Friday afternoon, areas that have already been hit hard this season—such as Orillia, Midland, Wiarton, Lion’s Head, and Tobermory—could see another 15 to 25 cm of snow. If the squall locks into place for an extended period, localized totals of up to 40 cm are possible.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

As of early Thursday evening, bands of lake effect snow are already forming off Lake Huron and Georgian Bay. These will continue to shift around throughout the evening, delivering bursts of heavy snowfall to different areas.

Right now, it looks like the heaviest snowfall will be concentrated across the Bruce Peninsula and along the southeastern Georgian Bay shoreline, including Collingwood, Barrie, Angus, and Keswick. Additional, weaker bands may impact regions east of Lake Huron, from Owen Sound to Goderich.

By midnight, models suggest that a narrow but intense squall could set up, stretching from the Bruce Peninsula, over Georgian Bay, and into Barrie. However, there’s still uncertainty about its exact strength and how stationary it will be overnight. Some models show it drifting north toward Midland and Orillia, while others keep it in place longer.

If the squall aligns just right, it could connect with both Lake Huron and Georgian Bay, allowing it to tap into additional moisture. This could make it stronger than expected, potentially bringing more snow to Barrie than initially forecasted. Right now, Barrie sits right on the edge between significant snowfall and minimal accumulation.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

By Friday morning, the squall will likely continue hammering the Bruce Peninsula and Simcoe County but may have shifted slightly north, putting Tobermory, Midland, and Orillia in the bullseye for heavy snow during the late morning.

Depending on its strength, the squall could even extend into portions of Durham and the Kawartha Lakes at times. This squall may remain stationary for several hours, with snowfall rates reaching 5-10 cm per hour.

It won’t take long for roads to become impassable, especially along the Highway 400 and Highway 11 corridors. Plows will struggle to keep up with such intense snowfall rates, and whiteout conditions will make travel extremely dangerous. If you can, stay home—this is the kind of snow that can lead to major travel disruptions and accidents.

By early Friday afternoon, the squall should gradually weaken as winds shift and become less favourable for lake effect snow.

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As with any lake effect event, snowfall totals will be highly variable, depending on where these narrow snow bands set up.

The hardest-hit areas are expected to be across the Bruce Peninsula, including Tobermory, Lion’s Head, and Wiarton, extending into Simcoe County in areas like Midland, Washago, and Orillia. These regions could see 15 to 25 cm, with localized totals near 40 cm possible in central Simcoe County, closer to Georgian Bay.

Surrounding areas—including Grey-Bruce, Huron, and Perth counties east of Lake Huron—could see 5 to 15 cm, though some spots may see little to no snow due to how localized these bands are. Southern Muskoka, portions of Kawartha Lakes, and Durham Region may also receive up to 5 to 10 cm in some areas.

The rest of Southern Ontario should see less than 5 cm of snow over the next 24 hours, as the lake effect snow stays confined to the snowbelt regions.

While the lake effect snow wraps up Friday, a much bigger storm could be on the way this weekend. A potential multi-day snowfall event is on track to begin Saturday, and continue into Sunday.

Right now, there’s still uncertainty regarding snowfall totals and the exact timing of the worst conditions, but early indications suggest that much of Southern Ontario—particularly Eastern Ontario and the Golden Horseshoe—could see 20-30 cm or more by the end of the weekend.

We’re waiting on the latest model data this evening and will have a preliminary forecast on this potential snowstorm later today or early Friday. Stay tuned!

Snow Squalls to End Off the Week in Parts of Southern Ontario With Up to 25cm of Snow Possible by Friday

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While we’ve had a break from snow squall activity over the past week, they are expected to return as we close out the week, bringing another round of lake-effect snow to areas around Lake Huron and Georgian Bay.

As the system that brought a messy mix of wintry weather moves out, colder air will briefly settle into Southern Ontario. This drop in temperature, combined with strong westerly to northwesterly winds blowing over the still mostly ice-free lakes, will create the perfect conditions for snow squall development.

Overnight Thursday, shifting winds will likely trigger several narrow bands of heavy snow that will sweep across Southern Ontario before becoming more organized over Lake Huron and Georgian Bay.

While these bands won’t last long—most areas will only see snow for 15 to 30 minutes—they could still create hazardous driving conditions. Strong wind gusts of 70-80 km/h will cause blowing snow, significantly reducing visibility on the roads.

However, for regions within the snowbelt, which have already been hit hard by squalls in recent weeks, this could be another significant snowfall event. Parts of Grey-Bruce and Simcoe County may see totals reaching 15 to 25 cm in the hardest-hit communities by the end of Friday.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

More organized squalls are likely to develop early Friday morning, targeting the Bruce Peninsula and extending into Simcoe County. This narrow but intense band will likely persist throughout much of the day, though it may shift somewhat as winds fluctuate.

Current model data indicates that the heaviest snow will remain focused within the Wiarton-to-Owen Sound corridor in Grey-Bruce and between Orillia and Barrie in Simcoe County. At times, the squall could extend further inland, bringing periods of heavy snow to parts of Kawartha Lakes, Durham, and Peterborough during the morning and afternoon.

By Friday evening, a shift in wind direction will bring a few hours of intense snowfall to parts of Southern Muskoka, including MacTier, Port Carling, Bala, Gravenhurst, and Bracebridge. However, this squall is expected to weaken quickly after midnight as winds subside.

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With the snow band moving around throughout the day, widespread extreme accumulations are less likely, but it will allow more regions to see bursts of heavy snowfall at different times.

We’re expecting total snowfall accumulations of 15 to 25 cm across the central Bruce Peninsula, including Wiarton and Lion’s Head, extending into most of Simcoe County.

The City of Barrie is expected to avoid the worst of the snowfall, but if the squall sinks slightly farther south for a few hours, the city could still see around 10-15 cm of accumulation.

For the rest of Grey-Bruce, including Owen Sound, Hanover, and Collingwood, as well as Muskoka, Kawartha Lakes, and Peterborough, snowfall totals will generally range between 5 to 10 cm, though some localized pockets may receive up to 15 cm.

Outside of the snowbelt, snowfall will be minimal, with 2-5 cm expected across the rest of Central Ontario and less than 2 cm for Eastern Ontario and the Golden Horseshoe.

Deep Southwestern Ontario will likely remain snow-free from this round of lake-effect snow.

PRECIPITATION TYPE - MAP FROM WEATHERBELL

After the snow squalls, attention will turn to Saturday night, which, at one point, looked like it could bring Southern Ontario its strongest winter storm of the season. However, recent model data now suggests that much of the system’s moisture may stay south of the border, shifting into the U.S. Northeast instead.

If this trend continues, instead of widespread snowfall totals of 10-20 cm, most of Southern Ontario could see just 5 to 10 cm—and even that might be on the high end.

For those hoping for a big winter storm, it looks like luck isn’t on your side this time. That said, we’re still in an active storm track, and the next few weeks will bring more chances for Southern Ontario to get hit with a classic winter storm.

Another Dumping of Snow as an Alberta Clipper Targets Southern Ontario With Up to 20cm of Snow by Wednesday

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As January 2025 draws to a close, Southern Ontario’s weather has varied greatly depending on the region.

Snowbelt areas near Lake Huron and Georgian Bay have been bombarded by persistent lake-effect snow over the past couple of weeks. Meanwhile, Eastern and Deep Southwestern Ontario have seen little snow this month, as no significant systems have impacted those areas.

That pattern is about to shift, with an Alberta Clipper poised to bring a widespread snowfall event across Southern Ontario. This system is expected to deliver 10 to 20 cm of snow to Eastern, Central, and Southwestern Ontario over the next 24 hours, including the snowbelt regions.

In addition to the clipper, snow squalls are forecast to develop Wednesday afternoon and continue into the evening. Combined system snow and lake effect snow could bring an additional 20 to 30 cm to areas east of Lake Huron between Tuesday and Wednesday.

PRECIPITATION TYPE - MAP FROM WEATHERBELL

Snowfall from the clipper has already begun moving into Southwestern Ontario near Lake Huron as of late Tuesday afternoon.

Moderate to heavy snow will spread eastward through the evening, with the heaviest snow expected in the Greater Toronto Area (GTA) and Central Ontario during the late afternoon and early evening.

Localized heavier snow is likely along the Lake Huron and Georgian Bay shorelines, particularly over the Bruce Peninsula, where lake enhancement will add extra moisture to the system.

PRECIPITATION TYPE - MAP FROM WEATHERBELL

For Southwestern Ontario, snowfall will begin to taper off by the evening and should exit areas southwest of Lake Simcoe by midnight.

Central and Eastern Ontario will continue to see snow through the early overnight hours, with the Ottawa Valley potentially experiencing snowfall until Wednesday morning, tapering off around sunrise.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

Following the system’s departure, lake effect snow is expected to ramp up over Lake Huron and Georgian Bay.

Models indicate disorganized snow bands developing off Lake Huron on Wednesday afternoon, impacting areas like Grey, Bruce, Huron, and Perth counties. These bands may occasionally extend as far as Kitchener and Hamilton.

Additionally, a snow squall may form southeast of Georgian Bay, bringing heavy snow to the Barrie and Innisfil areas Wednesday afternoon. The intensity and duration of this squall remain uncertain.

By Wednesday evening, activity over Lake Huron may consolidate into a stronger squall targeting the corridor between Southampton and Kincardine, potentially extending to the Hanover area. This squall could lead to rapid snowfall accumulation before gradually weakening after midnight.

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The highest snowfall totals over the next 24 hours are expected in the Grey-Bruce region.

Communities such as Port Elgin, Kincardine, Owen Sound, Chatsworth, Mildmay, and Hanover are forecast to receive 10 to 15 cm of snow from the clipper and an additional 10 to 20 cm from lake effect snow on Wednesday.

This could bring total accumulations to 20 to 30 cm, with isolated pockets potentially exceeding 30 cm.

Across Central and Eastern Ontario, Alberta Clipper snowfall is generally expected to range from 10 to 15 cm. Areas southeast of Georgian Bay, including Barrie, may see near 20 cm due to the added snow from Wednesday afternoon’s localized squalls.

Lower totals are expected in the GTA and Niagara regions, as the system’s moisture will primarily focus further north, and lake enhancement will not play a role.

Snowfall amounts in the GTA are expected to range from 4 to 8 cm, with Hamilton and the Niagara corridor seeing even less at 2 to 4 cm.

Deep Southwestern Ontario, including Windsor, Chatham, Sarnia, and London, will see little to no snow from this system. London could receive a few centimetres, while Windsor may only see a trace.

Looking ahead, we are monitoring a potential system moving in on Friday, which could bring snow and freezing rain to parts of Southern Ontario. Stay tuned for updates.

Snow Squalls Return to Southern Ontario This Weekend With Up to 20cm of Snow; Potential Wind Storm on Monday

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Southern Ontario has been gradually climbing out of the deep freeze earlier this week, which brought wind chills plunging into the -30s. This temporary reprieve has also slowed down the lake-effect snow machine.

However, a fresh surge of cold air over the next 24 hours will reignite the potential for snow squalls, particularly around Georgian Bay.

The good news is that this round of snow squall activity should be relatively short-lived. The squalls are expected to drift rather than anchor in one spot, which will help limit overall snowfall accumulation.

By the end of Sunday, areas along the eastern Georgian Bay shoreline and the Bruce Peninsula are forecast to receive between 10 and 20 cm of snow.

Despite the shorter duration, these squalls could still create hazardous conditions. Wind gusts will likely lead to blowing snow, further reducing visibility on roads and making travel potentially dangerous.

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Looking ahead, once the snow squalls subside late Sunday, attention shifts to a potentially significant windstorm developing across Southern Ontario starting Monday morning and lasting through the day.

Based on the latest data, wind gusts could approach or even exceed 100 km/h in some regions.

This powerful wind event will coincide with the arrival of a weather system bringing widespread snowfall to Southern Ontario beginning Monday afternoon.

While snowfall totals from the system are expected to range between 5 and 15 cm, the combination of strong wind gusts and falling snow could lead to blowing snow and, in some areas, blizzard conditions.

Driving conditions during Monday’s evening commute are expected to be very poor, with a high risk of power outages in areas that experience the strongest wind gusts.

Be prepared for possible heating disruptions if outages occur, as temperatures are forecast to drop sharply Monday night.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

The cold front responsible for these changing conditions will sweep through Southern Ontario on Saturday evening. While surface temperatures will remain relatively stable, colder air aloft will fuel the lake-effect snow machine.

As a result, heavier snow pockets may develop east of Georgian Bay, particularly in the Parry Sound and northern Muskoka regions, aided by lake enhancement.

Snow squalls could also form within this setup, bringing locally higher snowfall amounts. Current projections suggest 5 to 15 cm of accumulation by Wednesday morning, but totals could reach up to 20 or even 25 cm if conditions align perfectly.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

High-resolution models show a significant snow squall developing over the southern Bruce Peninsula on Sunday morning.

This squall may extend across Georgian Bay, reaching Simcoe County and parts of Kawartha Lakes. It appears likely to linger for several hours between Orillia and Barrie, producing intense snowfall with rates approaching 5 cm per hour.

As the squall moves into Simcoe County during the afternoon, it is expected to weaken, leading to reduced snowfall rates. Additionally, weaker bands of lake-effect snow could develop off Lake Huron, potentially affecting areas like Kincardine, Hanover, and even parts of the Greater Toronto Area.

However, these bands are less certain and may only persist for a few hours on Sunday morning.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

By Sunday evening, snow squall activity will likely shift northward into Muskoka and Parry Sound, intensifying briefly and delivering heavy snow to areas like Port Carling and Bracebridge.

Organized lake-effect snow activity should taper off by midnight, although minor flurries may linger into early Monday morning.

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Because the squalls are expected to move frequently, snowfall will be spread across a wider area rather than concentrating in one location.

Most regions along the eastern Georgian Bay shoreline, including Barrie, Muskoka, and Parry Sound, are forecast to receive between 10 and 20 cm of snow by Sunday evening. This also applies to the Bruce Peninsula and areas like Owen Sound and Meaford.

Localized amounts exceeding 20 cm are possible, particularly in the corridor between Orillia and Barrie, where intense snow squalls are expected on Sunday morning. However, the current data does not support widespread totals in the 20-30 cm range.

Outside the primary snowbelt areas, regions such as Haliburton, Lindsay, Keswick, and Flesherton are likely to see 5 to 10 cm of snow, depending on the placement of snow squalls and how far inland they extend.

For the rest of Southern Ontario, snowfall amounts will generally be less than 5 cm, with most of the snow falling on Saturday evening and overnight.

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The windstorm on Monday is expected to bring the strongest gusts to higher elevations, including the Dundalk Highlands, Collingwood, and Orangeville.

Wind gusts in these areas could reach 100 to 110 km/h, with similar strength expected along the escarpment, down into Hamilton, and across the Niagara region along the Lake Erie shoreline.

In Southwestern Ontario, gusts could exceed 90 km/h in areas east of Lake Huron, extending into Kitchener and the western Greater Toronto Area.

Elsewhere across Southern Ontario, gusts will likely range from 80 to 90 km/h, while Central and Eastern Ontario could see slightly weaker gusts of 70 to 80 km/h.

PRECIPITATION TYPE - MAP FROM WEATHERBELL

The addition of widespread snowfall on Monday afternoon and evening will exacerbate the impact of the wind. Blowing snow could create whiteout conditions, and some areas may experience blizzard-like conditions, especially in Southwestern Ontario.

While snowfall totals from this system aren’t expected to be excessive, with 5 to 15 cm possible across Southwestern and Central Ontario, the combination of snow and strong winds will make travel extremely challenging.

Further details on timing and accumulation specifics will be shared in a forecast update on Sunday. Stay tuned!

High-Impact Snow Squall Event Could Bring Up to 100 cm and Blizzard Conditions to Southern Ontario’s Snowbelt Starting Monday

MAP UPDATED @ 3:30 PM - JANUARY 20, 2025 - NOTE: YOU CAN CLICK ON THE MAP TO OPEN A ZOOMABLE IMAGE

Chilly Arctic air has begun sweeping into Southern Ontario this weekend, marking the return of lake-effect snow activity off the Great Lakes. While snow squalls on Sunday have been relatively limited, they are expected to organize and intensify as the evening progresses.

Intense snow squalls are set to impact areas around Lake Huron and Georgian Bay from Monday through Tuesday. Portions of the Niagara region and Prince Edward County may also experience squalls driven by activity off Lake Ontario and Lake Erie.

Moderate wind gusts of 50-60 km/h are likely to develop on Monday morning. When combined with heavy snow, these winds could cause blowing snow and localized blizzard-like conditions in some areas. Poor travel conditions are anticipated, with road closures possible throughout Monday and into Tuesday.

The Bruce Peninsula is expected to bear the brunt of these squalls. A prolonged and intense squall is likely to lock in over the region from Monday afternoon through Tuesday, with snowfall totals potentially approaching 100 cm.

Other areas along the Lake Huron shoreline, as well as parts of Simcoe County and Muskoka, could see snowfall accumulations of 25-50 cm by the end of Tuesday.

This forecast also extends to the southern tip of Prince Edward County, south of Picton, where a Lake Ontario squall could drift across the county before moving into New York State.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

As of Sunday evening, a pocket of heavy snow over Lake Ontario is affecting northern Niagara. Meanwhile, a squall over Lake Huron has diminished but is expected to reorganize by midnight.

According to the latest model data, a very narrow yet intense squall is likely to develop over the Goderich area overnight. Snowfall rates could reach 10-15 cm per hour, with higher ratios due to colder temperatures.

This could result in rapid snow accumulation across Huron County, particularly in the Goderich region, through Monday morning.

There is some uncertainty regarding how far inland this squall will extend. However, it could potentially stretch into the Kitchener area, through Burlington and Hamilton, and become further enhanced as it moves back onshore over the Niagara region via Lake Ontario.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

By Monday afternoon, a shift to more westerly winds is expected, pushing the Lake Huron squall towards the Bruce Peninsula. The squall is predicted to stall over the northern and central parts of the peninsula by Monday evening.

Wind gusts will strengthen throughout Monday afternoon and evening, reaching 50-60 km/h in some areas. These winds are likely to create blowing snow and near-zero visibility, making travel nearly impossible east of Lake Huron. While conditions may not officially meet blizzard criteria, they will be very close.

Model projections diverge on the squall's movement after it crosses Georgian Bay. Canadian models suggest a variable wind direction could cause the squall to curve northward into Muskoka and Parry Sound instead of continuing east.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

Meanwhile, the American model indicates a more southerly trajectory, targeting Midland, Honey Harbour, and Washago. This model also suggests secondary squall activity could impact southern Bruce-Grey areas, including Port Elgin and Owen Sound.

Both models agree that upper-level winds will likely keep the squall close to the Georgian Bay shoreline. This may spare inland areas like Bracebridge, Gravenhurst, and Orillia from the heaviest snowfall, though the squall's reach could still surprise some locations.

There is also uncertainty regarding squalls over Lake Ontario and Lake Erie. While these squalls may drift northward into Fort Erie and southern Prince Edward County, they could remain concentrated south of the border.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

Snow squall activity is expected to remain stationary through Monday night into Tuesday morning, with snowfall rates of 5-10 cm per hour possible.

The Bruce Peninsula squall may gradually drift southward on Tuesday afternoon, although it is expected to weaken slightly as wind directions shift. Despite this, squalls will likely persist over the Grey-Bruce region throughout Tuesday.

Snow squalls are anticipated to continue into Wednesday, although their intensity and direction remain uncertain. Southwesterly winds may develop, which could direct squalls over the Bruce Peninsula and extend into the Parry Sound region.

MAP UPDATED @ 3:30 PM - JANUARY 20, 2025 - NOTE: YOU CAN CLICK ON THE MAP TO OPEN A ZOOMABLE IMAGE

UPDATED FORECAST (3:30 PM - JAN 20, 2025)

Muskoka, before you grab a pitchfork to take out your snow frustrations, you might want to trade it in for a snow shovel—you’re going to need it. 😉

The latest model data this morning doesn’t bring good news for those in Muskoka hoping for a break from the snow. How does another 50-100 cm sound?

In our initial forecast, we mentioned that model data suggested snow squall activity would stay primarily along the Georgian Bay shoreline. This meant that areas further inland, such as Bracebridge, Port Carling, and Gravenhurst, could avoid the brunt of the snow.

Unfortunately, the newest data paints a different picture. This morning’s updates indicate that snow squalls will push much further inland than originally expected. The models also show an increase in the intensity of these squalls, starting late this afternoon and continuing all day through Tuesday.

As a result, we’ve made adjustments to our forecast, extending the zone of heavy snow further inland east of Georgian Bay. Additionally, we’re now introducing a 50-100 cm snowfall zone for Muskoka, similar to what was previously focused over the Bruce Peninsula.

Locations such as Port Carling, Rosseau, Port Sydney, and Bracebridge are now directly in the crosshairs, with the potential for up to 100 cm of snow by the end of Tuesday. Meanwhile, the forecast for the Bruce Peninsula—covering Tobermory, Lion’s Head, and Wiarton—remains unchanged, with totals still expected to reach 50-100 cm.

For the rest of Muskoka, including Huntsville and Gravenhurst, as well as Parry Sound and Midland, snowfall accumulations of 25-50 cm are likely. This range also applies to the Owen Sound, Meaford, and Port Elgin areas.

You might notice a slight reduction in the forecast east of Lake Huron. This adjustment reflects snowfall that already occurred last night and early this morning, especially in areas like Goderich. These regions are expected to see an additional 15-25 cm of snow by the end of Tuesday.

Our forecast for Fort Erie and Prince Edward County remains unchanged. Squall activity off Lake Erie and Lake Ontario could bring 15-25 cm of snow to the southern Niagara region, including Fort Erie. Meanwhile, southern Prince Edward County, particularly south of Picton, could see totals ranging from 25-50 cm.

See below for our Lake Ontario and Lake Erie forecast.

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PREVIOUS FORECAST:

Given the frequent mention of the Bruce Peninsula in this forecast, it’s no surprise that this region is expected to receive the most snowfall from this event.

Accumulations of 50-100 cm are projected for areas including Tobermory, Lion’s Head, and Wiarton. Some locations may even exceed 100 cm if the squall remains stationary for an extended period.

Along the Lake Huron shoreline, areas such as Goderich, Point Clark, Kincardine, Port Elgin, Chatsworth, Owen Sound, and Meaford are likely to see 25-50 cm of snowfall by Tuesday’s end. As with most snow squalls, localized variations in totals are expected based on the squall's exact path.

Similar snowfall amounts of 25-50 cm are possible along the eastern Georgian Bay shoreline, including Midland and MacTier. However, these totals will be highly localized, as the squall’s path is still uncertain.

Further inland, areas east of Lake Huron, such as Listowel, Hanover, and Flesherton, are forecasted to receive 15-25 cm of snow. Western Muskoka and Simcoe County, including Port Carling, Bala, Washago, and Gravenhurst, could also see 15-25 cm.

Brief periods of heavy snow are possible in the western GTA, Kitchener, Barrie, and parts of Muskoka, leading to localized accumulations of 5-15 cm. Most areas will likely remain on the lower end of this range, but isolated pockets could approach 15 cm.

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The St. Catharines and Niagara-on-the-Lake regions are currently experiencing locally heavy snow, which is expected to continue overnight. By Monday morning, total snowfall, including amounts already fallen, could range from 15-25 cm.

Fort Erie may also see 15-25 cm of snow if the Lake Erie squall edges far enough north. However, there is a possibility that the squall will remain south of the border, resulting in minimal accumulation on the Canadian side.

In Prince Edward County, the southernmost tip exposed to Lake Ontario could see 25-50 cm of snow. Slight shifts in the squall’s position could significantly impact snowfall totals, with Picton potentially receiving 15-25 cm under favourable conditions.

The rest of Southern Ontario is expected to see less than 5 cm of snow from this event. The Ottawa Valley and areas in deep southwestern Ontario will likely experience the least snowfall, with accumulations of less than 2 cm by Tuesday.

Frosty Start Early This Week as Extreme Cold Brings Intense Snow Squalls in Parts of Southern Ontario

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Get ready for a blast of Arctic air across Southern Ontario this week! A surge of polar air will cause temperatures to plummet over the weekend and into early this week.

This extreme cold is also expected to trigger a multi-day snow squall event, which could result in significant snowfall for the usual snowbelt regions.

Dangerous wind chills approaching -30°C by Monday night, combined with intense snowfall rates, will create hazardous travel conditions. The hardest-hit areas are likely to be along the Lake Huron shoreline, including Grey, Bruce, and Huron counties.

Moderate wind gusts of 40-60 km/h could lead to blowing snow, with localized blizzard-like conditions possible. Non-essential travel in these regions should be avoided, as the extreme cold could quickly turn life-threatening if you become stranded.

While exact snowfall totals remain uncertain, the cold temperatures will enhance snowfall ratios, resulting in higher-than-usual snowfall rates for the same amount of moisture. Portions of Grey and Bruce counties along the shoreline could see snowfall accumulations exceeding 50 cm.

Lake Ontario and Lake Erie may also see localized lake-effect snow starting Sunday night and continuing through Tuesday. The Niagara region and Prince Edward County could receive 25-50 cm of snow in some areas, though accumulations will be highly localized.

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TIMING

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

The event will begin with light snow across Southwestern Ontario and the Golden Horseshoe on Monday evening. Lake enhancement along the Lake Huron shoreline and parts of the Western GTA and Northern Niagara region is expected.

However, it’s unclear how far these snow bands will extend inland, with some models suggesting they’ll remain close to the shoreline.

For example, high-resolution Canadian models show an intense but narrow squall near the Goderich region that doesn’t stretch far inland.

Similarly, a Lake Ontario squall may take an unusual path through Grimsby, St. Catharines, and Niagara-on-the-Lake, staying close to the shoreline.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

Overnight Sunday into Monday morning, a more stable wind direction could allow a Lake Huron squall to push farther inland, potentially affecting Kitchener, Hamilton, and Burlington.

These areas could see a few hours of heavy snow during the morning commute.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

By late Monday morning, the squall may gradually drift northward, reducing snowfall around Goderich as the wind shifts westerly. The Grey-Bruce region is likely to bear the brunt of the snow squalls at this point.

The Toronto area might see the edge of the squall by late morning, but snow intensity there remains uncertain.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

On Monday evening, a persistent squall is expected to form across the Bruce Peninsula and extend over Georgian Bay into Muskoka.

However, it may struggle to reach far inland, confining the heaviest snow to shoreline areas like Parry Sound, MacTier, and Bala. Bracebridge and Gravenhurst might avoid the worst of the snow—a welcome break after this winter’s relentless storms.

Lake Erie and Lake Ontario squalls will also intensify Monday night, with the Lake Erie squall drifting north into Port Colborne and Fort Erie.

Meanwhile, the Lake Ontario squall could impact southern Prince Edward County. Unfortunately, these squalls are unlikely to shift much overnight, meaning sustained snowfall and high winds could create treacherous conditions.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

As Tuesday morning approaches, the Lake Huron squall may refocus on southern Bruce County, including Owen Sound, Sauble Beach, Kincardine, and Hanover. These areas could face significant snowfall throughout the day.

The Lake Erie squall may drift southward, offering some relief to the Niagara region, though Fort Erie could remain under heavy snow. For Prince Edward County, the Lake Ontario squall may persist through much of Tuesday, delivering relentless snowfall.

A wind shift late Tuesday should end snow squalls off Lakes Erie and Ontario, but activity off Lake Huron may reposition toward the Bruce Peninsula and Muskoka.

Details for snow squall activity beyond Tuesday night will be covered in future updates.

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THE BIG CHILL

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The big factor fueling these squalls is the frigid air moving over the relatively warm Great Lakes.

Temperatures could drop to -20°C by Monday night, with wind chills in the -30s for many parts of Southern Ontario, including the southwest.

This dangerous combination of extreme cold and heavy snow could lead to life-threatening conditions if you get stranded outdoors.

That’s why it’s critical to avoid travel during this period and stay home whenever possible.

School bus cancellations are likely on Monday and Tuesday due to both extreme cold and snow squalls.

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HOW MUCH TO EXPECT

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As always with snow squalls, their narrow and shifting nature makes forecasting totals challenging. Some areas may see just 1 cm, while others a short distance away could be buried under 50 cm.

Model data suggests that Bruce County will be hardest hit, particularly along the Bruce Peninsula, Port Elgin, Kincardine, and Point Clark, where over 50 cm of snow is possible.

Huron and Grey counties, including Owen Sound, Chatsworth, Hanover, Wingham, and Goderich, could see up to 50 cm in places.

Inland areas like Kitchener and Orangeville may get up to 25 cm, while the Eastern Georgian Bay shoreline, including Muskoka, could see similar totals.

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The Niagara region, especially along its northern and southern edges, may get up to 25 cm of snow between Monday night and Tuesday. In Prince Edward County, localized totals of 50 cm are possible, especially in southern areas.

Kingston could see up to 10 cm, while eastern Ontario and deep southwestern Ontario will likely receive no more than 5 cm.

Stay tuned for updates as high-resolution models refine snowfall predictions.

For now, it’s clear that this storm will bring a mix of extreme cold, heavy snow, and treacherous travel conditions to Southern Ontario. Stay safe and stay prepared!

Intense Snow Squalls Return to Parts of Southern Ontario on Monday; Possible Deep Freeze for Late January

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⬇️ ZOOMED IN MAP CAN BE FOUND FURTHER DOWN ⬇️

The first half of January is almost behind us, and in Southern Ontario, the weather has shifted significantly compared to December. Colder temperatures have dominated, leading to several bouts of snow squall activity off Lake Huron and Georgian Bay. These events have primarily impacted regions southeast of the lakes.

The threat of snow squalls is set to return this week, with the heaviest snow expected east of Lake Huron and Georgian Bay. A predominant westerly flow will target areas such as Parry Sound, Bracebridge, Gravenhurst, and parts of Grey and Bruce counties. This pattern is reminiscent of what we experienced in early December, with heavy snow focused in the snowbelt regions east of Georgian Bay.

Snow squalls are forecasted to develop Monday afternoon and further intensify into the evening and overnight hours. Rapid snowfall accumulation and near-zero visibility are likely, especially late Monday into early Tuesday.

By the time the squall activity tapers off on Tuesday afternoon, some localized areas in the Muskoka and Parry Sound regions could see totals between 25 and 50 cm.

A brief reprieve from lake-effect snow is expected after Tuesday as milder air moves into Southern Ontario. However, another Arctic plunge is anticipated by early next week, potentially bringing some of the coldest air of the season.

Wind chills could make it feel like -30°C or even -40°C, especially in Central and Eastern Ontario!

This upcoming cold snap could also reignite intense lake-effect snow activity, with several rounds of squalls likely to impact the snowbelt regions throughout the rest of January.

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BREAKING DOWN THE TIMING OF THE SQUALLS

Before the snow squalls begin Monday, a weak clipper system is forecasted to move across Southern Ontario late Sunday into early Monday morning. While this system will lack significant moisture, it may bring light snowfall of 2 to 5 cm in most areas, with localized pockets potentially reaching up to 5 cm.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

In the wake of the clipper, lake-effect snow is expected to ramp up east of Georgian Bay on Monday afternoon. Initially, the snow may be disorganized, spreading moderate to heavy snowfall across Muskoka and parts of Grey and Bruce counties.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

By Monday evening, forecast models indicate the formation of a more organized snow squall. This band is expected to stretch from the Bruce Peninsula across Georgian Bay and inland between MacTier and Parry Sound.

The squall could remain stationary overnight, leading to rapid snowfall accumulation at rates of 5 to 10 cm per hour.

Model projections differ slightly regarding the exact placement of the most intense squall. The American model places the heaviest snow over Parry Sound, Pointe au Baril, Sprucedale, and Burk’s Falls.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

Meanwhile, the Canadian model suggests the squall may shift south after midnight, targeting areas such as Port Carling, Rosseau, Port Sydney, and Bracebridge for the heaviest snowfall.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

Both models agree that the squall will gradually sink southward by late Tuesday morning, bringing heavy snow to northern Simcoe County, including Midland and Orillia.

However, there is uncertainty about the intensity and duration of the squall as it moves further south into Barrie.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

While Georgian Bay will see the most intense squalls, Lake Huron is also expected to generate less intense snow bands Monday evening into Tuesday morning. These bands could impact Owen Sound, Kincardine, and Hanover, with bursts of heavy snow.

As the wind shifts southward, areas like Goderich and London may briefly experience lake-effect snow Tuesday morning into the afternoon.

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WHO COULD GET BURIED IN SNOW

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As is typical with lake-effect snow, snowfall totals will vary widely depending on where the narrow bands persist. The highest accumulations are expected in Parry Sound, Rosseau, Port Carling, Port Sydney, Bracebridge, and Gravenhurst, where 25 to 50 cm of snow is possible by Tuesday afternoon.

In some areas, totals could exceed 50 cm if the squall remains stationary for an extended period.

Surrounding areas such as Midland, Washago, Coboconk, Minden, Huntsville, and Sprucedale may see snowfall totals of 15 to 25 cm.

The Grey-Bruce region, including Kincardine, Port Elgin, Wiarton, Lion’s Head, Tobermory, Owen Sound, Chatsworth, Hanover, and Meaford, is expected to receive 15 to 25 cm, with localized totals of 30 to 40 cm if squalls intensify.

Elsewhere in Central and Southwestern Ontario, snowfall amounts will range from 5 to 15 cm, combining accumulation from the weak clipper system and lake-effect snow. Most areas will see closer to 5 cm, with lake-effect zones reaching 10 to 15 cm.

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

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SNOW SQUALL WATCH ISSUED BY ENVIRONMENT CANADA

CURRENT ENVIRONMENT CANADA ALERTS AS OF SUNDAY EVENING

Environment Canada has issued snow squall watches for areas around Lake Huron, Georgian Bay, and Lake Superior.

The highest totals in these watches match our forecast, with 20 to 40 cm expected for Parry Sound and Muskoka and 15 to 25 cm for the Grey-Bruce region.

Northern Ontario, including Sault Ste. Marie and Manitoulin Island could see localized snowfall of 10 to 20 cm from Monday evening into Tuesday morning.

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LOOKING AHEAD TO THE REST OF JANUARY

The persistence of lake-effect snow this far into January may seem unusual, but the Great Lakes remain relatively ice-free and warmer than usual due to a mild fall and warm start to winter. This provides ample moisture for snow squalls when Arctic air moves in.

ICE COVERAGE MAP AS OF JANUARY 11, 2025 - source: NOAA

Colder weather in recent weeks has helped cool the lakes and increased ice coverage, particularly in shallower areas like Lake Erie and the shorelines of Lake Huron and Georgian Bay.

Ice coverage has risen from 1% at the start of January to over 10% as of January 11.

TEMPERATURE ANOMALY - MAP FROM WEATHERBELL

Looking ahead, a significant Arctic blast is expected during the January 20–24 period, with temperatures 10 to 20 degrees below seasonal norms across much of Southern Canada and the northern U.S.

Southern Ontario could experience lows well below -20°C, potentially nearing -30°C in some areas. Wind chills could make it feel as cold as -35°C to -40°C, particularly in Central and Eastern Ontario.

This intense cold will likely bring additional snow squalls and accelerate ice formation on the Great Lakes. If current trends continue, lake-effect snow activity could diminish significantly by the end of the month as ice coverage increases, shutting off the moisture source for squalls.

For snowbelt residents weary of lake-effect snow, relief may finally be on the horizon!

Widespread Snowfall to End the Week Across Southern Ontario on Friday; Up to 5-10cm Possible

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While 2025 began with heavy snow across parts of Southern Ontario, most of the activity so far has been confined to traditional snowbelt regions. That’s about to change, as a new system is set to bring the first widespread snowfall of the year to much of Southern Ontario starting Friday.

Most of Southwestern, Central, and Eastern Ontario can expect snowfall totals of 5 to 10 cm between Friday afternoon and Saturday morning. However, areas along the Lake Huron shoreline and into the Bruce Peninsula may see enhanced snowfall, with totals reaching 10 to 20 cm due to lake-effect activity and embedded snow squalls.

As the system moves out, additional snowfall is likely over the weekend. Lake-effect snow squalls developing southeast of Lake Huron and Georgian Bay could bring localized accumulations of 20 to 30 cm from Saturday afternoon into Sunday.

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SNOWFALL TIMING

PRECIPITATION TYPE - MAP FROM WEATHERBELL

The system-related snowfall will begin spreading into Southwestern Ontario late Friday afternoon, with regions near Lake Huron, including Deep Southwestern Ontario, seeing snow first.

Through the dinner hours, the snow will advance northeast, gradually reaching the Golden Horseshoe and portions of Central Ontario by Friday evening. By midnight, snow will cover most of Southern Ontario, extending into Eastern Ontario.

PRECIPITATION TYPE - MAP FROM WEATHERBELL

The most intense period of snowfall is expected overnight Friday into early Saturday morning. While the snow will generally be light, it could lead to several hours of steady accumulation, potentially impacting travel.

Exercise caution if you plan to drive during this time, and remember to adjust your speed to match road conditions.

For areas along the Lake Huron shoreline and into the Bruce Peninsula, lake-enhanced snowfall could intensify during the evening and overnight hours on Friday, resulting in heavier accumulations compared to surrounding areas.

Snowfall from this system will taper off from west to east starting early Saturday morning in Southwestern Ontario, with Eastern Ontario holding onto snow until late morning.

Flurries may linger into Saturday afternoon, especially in some regions.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

As the system exits, lake-effect snow squalls may develop off Lake Huron and Georgian Bay by Saturday afternoon. Forecast models currently show some uncertainty about how organized these squalls will be and whether they will lock into specific areas for prolonged periods.

Higher-resolution models are just coming into range, so a detailed forecast for snow squall activity will be issued on Friday.

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HOW MUCH SNOW TO EXPECT

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In terms of totals, most of Southern Ontario will see 4 to 8 cm of snowfall, with slightly higher amounts of up to 10 cm possible in localized areas. This includes the east end of the Greater Toronto Area (GTA), such as Oshawa, and parts of Southwestern Ontario due to minor lake enhancement from Lake Ontario and Lake Huron.

The Golden Horseshoe and Ottawa Valley are expected to see slightly lower snowfall amounts, closer to 3 to 6 cm.

A zone along the Lake Huron shoreline—including Grand Bend, Goderich, Kincardine, and the Bruce Peninsula—could see locally higher accumulations by Sunday afternoon. Current estimates suggest 10 to 15 cm for these areas, with up to 20 cm possible for the Bruce Peninsula.

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WEEKEND SNOW SQUALL PREVIEW

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Environment Canada has identified areas near Barrie, Goderich, and London as hotspots for the most intense snow squalls over the weekend.

Here’s Environment Canada’s weekend outlook:

Saturday, January 11, 2025: “Lake effect snow squalls off Lake Huron and Georgian Bay are expected to develop Saturday afternoon. Local snowfall amounts of 10 to 15 cm are possible along with reduced visibility in heavy snow.”
Sunday, January 12, 2025: “Lake effect snow squalls off Lake Huron and Georgian Bay are expected to continue on Sunday. Local snowfall amounts of 10 to 15 cm are possible along with reduced visibility in heavy snow.”

As always, stay tuned for updates, especially if you’re in areas likely to experience lake-effect snow. Stay safe, and plan ahead for winter driving conditions!

Mid-Week Squalls Could Dump Up to 25-50cm of Snow to Parts of Southwestern Ontario by Thursday

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The New Year has certainly started on a frigid note across Ontario, as Arctic air has firmly settled over the region in recent days. These cold temperatures, combined with open lakes, have created the perfect conditions for lake-effect snow. Late last week and into the weekend, parts of the province experienced significant snowfall, with totals southeast of Georgian Bay reaching or exceeding 50 cm.

Over the past 24 hours, the lake-effect machine has largely taken a break, aside from some minor activity south of Lake Huron and Georgian Bay. However, that respite will be short-lived. Beginning Tuesday evening, snow squalls are expected to return with a vengeance as wind directions realign and even colder air moves into the region. These squalls are anticipated to persist through Wednesday and into early Thursday before tapering off.

This round of lake-effect snow will likely target areas that were largely spared during the last event. The focus this time will be on regions southeast of Lake Huron and along the southern shoreline of Georgian Bay. Some of the hardest-hit areas could include London and Collingwood, with snowfall totals potentially ranging from 25 to 50 cm over the next 48 hours.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

As for the timing, models differ slightly on the intensity and precise placement of the squalls. The latest data suggests snow squalls could begin organizing as early as Tuesday evening. The squall off Georgian Bay is expected to impact the Collingwood and Blue Mountain area, stretching inland toward Creemore, Alliston, and Shelburne. It may also affect the Highway 400 corridor just south of Barrie.

Meanwhile, activity off Lake Huron could produce multiple squalls developing between Kincardine and Grand Bend, with bands extending inland in a southeasterly direction. This puts portions of Huron, Perth, and Middlesex counties in the crosshairs.

The Georgian Bay squall appears to be somewhat weaker than its Lake Huron counterpart, likely due to the smaller lake surface area supplying moisture. That said, it is expected to remain relatively stationary through the overnight hours into Wednesday, resulting in steady snowfall accumulation and reduced visibility.

Travel in this area will likely be challenging from Tuesday night into Wednesday, with little improvement expected until the activity begins to subside overnight.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

Lake Huron squalls, on the other hand, are expected to shift around more frequently, spreading out snowfall accumulations. By Wednesday morning, the primary squall is forecasted to come ashore around Grand Bend, extending inland toward Lucan, Strathroy, and London.

There is still some uncertainty about whether the squall will directly impact the City of London or remain just northwest. Western parts of the city are likely to see the heaviest snowfall, while eastern areas may receive lighter accumulations.

Scattered snow squalls east of Lake Huron are expected to continue affecting Huron and Perth counties throughout Wednesday. These squalls may vary in intensity, and if one becomes particularly organized and stalls over an area, rapid snowfall accumulation could occur.

The most intense conditions are expected during the day on Wednesday, extending into the evening and overnight hours.

HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

By midnight, the lake-effect activity is expected to become more localized. The Georgian Bay squall will likely retreat closer to the shoreline, while the Lake Huron squalls may consolidate into a narrower band near Grand Bend, extending into the London area.

While this will reduce the overall impact, areas caught under these more focused squalls could experience increased snowfall rates for several hours overnight into early Thursday morning.

By pre-dawn Thursday, the lake-effect activity is anticipated to taper off, with the Georgian Bay squall dissipating before sunrise and the Lake Huron squall following a few hours later.

Snowfall totals from this round of snow squalls will vary widely, as is typical with these events. This forecast is particularly tricky due to discrepancies in model data regarding the intensity of the snow bands, which will significantly affect accumulation.

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Based on the current environment and dynamics, there is potential for 25 to 50 cm of snow in areas such as London, Lucan, Grand Bend, Clinton, and Collingwood. However, these totals are not guaranteed, as exact amounts will depend on where the bands set up.

For London, in particular, snowfall accumulations will likely be heavier in the northwest, while eastern areas may only see totals between 10 and 25 cm.

Surrounding areas like Goderich, Point Clark, Mitchell, Strathroy, and St. Thomas could see localized accumulations of 15 to 25 cm, depending on the positioning of the bands. Similarly, areas southwest of Barrie, including Angus, Alliston, and Beeton, may receive 10 to 20 cm as the Georgian Bay squall extends inland.

Outside these regions, significant snowfall is not expected due to the highly localized nature of lake-effect activity. However, portions of Eastern Ontario near the U.S. border and areas east of Ottawa may see 5 to 10 cm of accumulation on Wednesday due to a separate system lingering over Quebec.

Snow Squall Blast Continues This Weekend as Parts of Southern Ontario Could See an Additional 25-50cm of Snow

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The New Year has certainly started on a snowy note for parts of Ontario's snowbelt regions. A multi-day snow squall event is underway around Lake Huron and Georgian Bay, with some areas already receiving over 50 cm of snow. Locations east of Lake Huron, Simcoe County, and parts of Kawartha Lakes have been among the hardest hit so far. While the activity off Georgian Bay weakened somewhat on Friday evening, it's expected to ramp up again by Saturday afternoon and continue through Sunday. Snow squalls will also persist east of Lake Huron Friday night into Sunday, though the bands will shift around multiple times during this period. By the end of the weekend, some areas could see an additional 25 to 50 cm of snow, with localized totals reaching as high as 75 cm. Combined with the snow that has already fallen, totals in the hardest-hit regions could exceed one meter (100 cm). This includes parts of Simcoe County, where 50 to 75 cm of snow has already accumulated over the past two days. As of Friday evening, multiple discrete squalls off Lake Huron are bringing heavy snow to areas stretching from Bayfield to Kincardine and as far inland as Woodstock, Kitchener, and Guelph. This activity is expected to continue through the night, with southern squalls gradually merging northward by early Saturday morning.

The New Year has certainly started on a snowy note for parts of Ontario's snowbelt regions. A multi-day snow squall event is underway around Lake Huron and Georgian Bay, with some areas already receiving over 50 cm of snow. Locations east of Lake Huron, Simcoe County, and parts of Kawartha Lakes have been among the hardest hit so far.

While the activity off Georgian Bay weakened somewhat on Friday evening, it's expected to ramp up again by Saturday afternoon and continue through Sunday. Snow squalls will also persist east of Lake Huron Friday night into Sunday, though the bands will shift around multiple times during this period.

By the end of the weekend, some areas could see an additional 25 to 50 cm of snow, with localized totals reaching as high as 75 cm. Combined with the snow that has already fallen, totals in the hardest-hit regions could exceed one meter (100 cm). This includes parts of Simcoe County, where 50 to 75 cm of snow has already accumulated over the past two days.

As of Friday evening, multiple discrete squalls off Lake Huron are bringing heavy snow to areas stretching from Bayfield to Kincardine and as far inland as Woodstock, Kitchener, and Guelph. This activity is expected to continue through the night, with southern squalls gradually merging northward by early Saturday morning.

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HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

By Saturday morning, an intense squall is expected to form between Sauble Beach and Kincardine, extending inland to areas such as Hanover, Dundalk, and Orangeville. This band may stretch as far east as the western GTA, including Mississauga and Brampton.

While overall accumulations in the GTA should remain around 5 cm or less, these squalls could still lead to near-zero visibility and hazardous travel conditions due to blowing snow.

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HOURLY SNOWFALL RATE/intensity - MAP FROM WEATHERBELL

For Georgian Bay, lingering lake-effect activity will continue Friday night into Saturday morning, though no significant squalls are expected until later in the day.

By mid to late Saturday afternoon, the Lake Huron squall is expected to shift northward as wind directions change. This will allow it to cross over the southern Bruce Peninsula and connect with Georgian Bay, bringing heavy snowfall to Simcoe County, particularly in the Barrie-Orillia corridor.

This squall may also extend into parts of northern York and Durham regions, as well as the Kawartha Lakes region.

As seen earlier in this event, the squall is expected to lock in place, leading to intense snowfall rates of 5 to 10 cm per hour late Saturday through Sunday. Driving conditions will deteriorate rapidly, and non-essential travel should be avoided due to the potential for road and highway closures.

By late Sunday morning, the Georgian Bay squall is expected to sink southward, bringing an end to the snow for areas southeast of the bay. Moderate to heavy lake-effect snow may persist in parts of Grey and Bruce counties throughout Sunday, with activity finally tapering off overnight into Monday morning.

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The heaviest snowfall totals are expected in areas such as Wiarton, Owen Sound, Kincardine, Hanover, Meaford, Collingwood, Wasaga Beach, Midland, Barrie, Orillia, and Beaverton. These regions could see an additional 25 to 50 cm of snow by the end of the weekend, depending on the squall locations.

Surrounding areas, including Goderich, Woodstock, Stratford, Kitchener, Guelph, Angus, Bradford, Lindsay, and Port Perry, may also see significant snowfall if the squalls align. These areas could receive 15 to 25 cm of snow, though amounts will vary widely due to the localized nature of snow squalls. Our forecast is intentionally broad to account for potential shifts in squall placement.

Snowfall amounts will drop off quickly outside the snowbelt regions. However, parts of the northern and western GTA could see 5 to 10 cm, with isolated amounts up to 15 cm. Even Toronto might get a few centimeters of brief, heavy snow as the bands shift inland.

Eastern and Deep Southwestern Ontario are not expected to see any significant snowfall from this event.