April 01, 2025

Mid-Week Freezing Rain Risk Threatens Southern Ontario After Last Weekend’s Devastating Ice Storm

April 01, 2025/ Brennen Perry

***NOTE: YOU CAN CLICK ON THE MAP TO OPEN A ZOOMABLE IMAGE***

With recovery efforts well underway across Central Ontario following the devastating ice storm last weekend—which left hundreds of thousands without power—a new weather threat is now on the horizon, potentially hindering progress.

A dynamic and complex system is expected to move into Southern Ontario starting Wednesday morning and continuing into Thursday, bringing with it a mix of impactful weather, including heavy snow, freezing rain, and even the risk of severe thunderstorms.

Unlike the recent ice storm, which brought over 30 hours of relentless freezing rain, this upcoming round will be more typical in nature. Most regions affected can expect four to eight hours of freezing rain, followed by a gradual transition to regular rain as temperatures rise.

While the severity won't match the last event, this system is still expected to bring 5 to 10mm of ice accretion in some of the hardest-hit zones, especially across higher elevations northwest of the Greater Toronto Area, including parts of the Dundalk Highlands and the Kitchener-Waterloo region.

That amount of ice is enough to snap tree branches and potentially cause power outages, especially with infrastructure already weakened. Thankfully, we don’t expect widespread or prolonged outages this time, and restoration efforts should be more manageable. However, with hydro crews still stretched thin from the last storm, even minor outages could take longer than usual to resolve.

Further north, across Central and Eastern Ontario, freezing rain is also expected—though it will be mixed at times with ice pellets and snow. These regions should see a faster changeover to rain, which will help limit overall ice build-up. Still, light icing and slick roads are possible through the afternoon and evening hours, particularly on untreated surfaces.

Adding to the concern are strong wind gusts, which are expected to develop Wednesday afternoon and could return overnight. Gusts may reach 70 to 90 km/h, especially in exposed areas of Central Ontario and regions east of Lake Huron. With already-compromised infrastructure, even moderate gusts could bring additional tree and power line damage.

**PRECIPITATION TYPE** - MAP FROM WEATHERBELL

Precipitation will begin spreading into Southwestern Ontario late Wednesday morning into the early afternoon. For areas in Deep Southwestern Ontario and along the Lake Erie shoreline, including Windsor, Chatham, and Sarnia, the precipitation will fall as rain from the start, limiting any freezing rain risk.

However, higher elevation zones—particularly those east of Lake Huron and extending through Kitchener, Guelph, and Orangeville—will be dealing with below-freezing surface temperatures trapped under a layer of warm air aloft. This setup is classic for freezing rain, as the rain freezes on contact with cold ground surfaces.

The Greater Toronto Area could see some brief periods of freezing rain as well, particularly in areas away from the immediate lakeshore where it tends to stay cooler. However, any icing here is expected to be minor and short-lived, quickly melting as temperatures rise above freezing.

By mid-afternoon, Central Ontario, especially areas surrounding Lake Simcoe, will likely start off with a wintry mix of wet snow and ice pellets as the first bands of precipitation arrive. These areas could then transition to a few hours of freezing rain before warming into plain rain overnight.

**ESTIMATED WIND GUSTS**- MAP FROM WEATHERBELL

As the afternoon progresses, wind gusts will begin to increase, particularly in regions east of Lake Huron and into parts of Central Ontario. While model guidance varies, most are pointing to a window of potentially damaging gusts between 70 to 90 km/h.

The NAM model continues to show gusts near 100 km/h, though this may be on the higher end of the spectrum. Overnight, another round of strong gusts is possible as a line of thunderstorms develops. If these storms materialize, localized wind gusts could reach similar or even stronger levels. The severe weather threat should remain confined to Deep Southwestern Ontario.

As we head into Wednesday evening, freezing rain will come to an end for much of the GTA as temperatures rise above the freezing mark. However, it is expected to persist longer across areas to the northwest, where colder air hangs on longer. This is where the most prolonged and severe icing is likely.

The freezing rain will also spread into parts of Central Ontario and the Bruce Peninsula, both of which were hit hard by the weekend storm and remain vulnerable to additional impacts.

Eastern Ontario will begin to see precipitation late in the day, starting with a burst of heavy snow, followed by a changeover to ice pellets and then freezing rain. How quickly this transition happens will determine how much snow is able to accumulate.

Some model scenarios suggest snowfall totals of 5 to 10 cm are possible, particularly in regions along the Quebec border including Ottawa.

By around midnight, temperatures will begin to climb across regions southwest of Lake Simcoe, triggering a changeover to rain. Overnight, heavy rainfall will continue to spread across Southwestern Ontario and into the Golden Horseshoe. This rain may come down heavily at times, especially in areas that see embedded thunderstorms.

There is also a risk of severe thunderstorms through the evening and overnight hours in Deep Southwestern Ontario, including Windsor, Chatham, and Sarnia. These storms could produce wind gusts up to 100 km/h, and while the overall tornado risk is low, it can’t be ruled out. A more detailed thunderstorm forecast will be issued on Wednesday if conditions continue to trend toward severe potential.

The freezing rain will gradually lift northward into the Sudbury–North Bay–Ottawa corridor overnight. While these areas may deal with a few hours of freezing rain early on, a transition to rain is expected before daybreak on Thursday.

The worst freezing rain impacts are expected across higher elevations of Southwestern Ontario and areas northwest of the GTA, where the freezing rain will last longest.

Some of these zones could see 5 to 10mm of ice accretion, and locally higher amounts over 10mm aren’t out of the question depending on exact temperatures and dynamics.

This kind of ice build-up can cause significant surface glazing and may lead to tree and power line damage. Areas most at risk include Listowel, Kitchener, Fergus, Guelph, Orangeville, Shelburne, and parts of York Region.

Northern parts of the GTA could see 2 to 5mm of ice, while areas closer to the lake should remain below 2mm, with ice melting quickly once temperatures rise.

Across Central Ontario and into the Ottawa region, a general 2 to 5mm of icing is expected, though this could trend higher if ice pellets are less dominant or the switch to rain is delayed.

**RAINFALL ACCUMULATION** - MAP FROM WEATHERBELL

Beyond the freezing rain, this system is also expected to deliver significant rainfall totals. Much of Southern Ontario could see 30 to 50mm of rain, with localized amounts up to 75mm possible in areas affected by thunderstorms.

With local waterways already running high due to spring runoff, this amount of rain could lead to flooding in low-lying areas, particularly where ice and debris continue to block drainage routes. This is of particular concern for communities still without power from the ice storm, as their ability to respond to flooding may be limited.

March 28, 2025

Dangerous Ice Storm Likely This Weekend With Widespread Power Outages Across Parts of Southern Ontario

March 28, 2025/ Brennen Perry

Concern is rapidly growing for what is shaping up to be a potentially devastating ice storm this weekend across parts of Central and Eastern Ontario. Prolonged freezing rain, beginning Friday evening, is expected to persist throughout much of the weekend, leading to substantial ice accretion on exposed surfaces.

This storm has the potential to reach ice accumulation levels not seen in years—or even over a decade. With up to 40mm of ice accretion possible, widespread power outages are likely in the hardest-hit regions, including Muskoka, Simcoe County, Kawartha Lakes, Peterborough, and Kingston.

Some of these power outages could last for days or even weeks, especially in more rural areas with dense tree coverage. Trees weighed down by ice are likely to fall, taking power lines with them. Travel conditions will also be significantly impacted, as ice-covered roads become extremely dangerous.

For Northern Ontario, the storm will start as a classic winter system, bringing heavy snowfall to Northeastern Ontario throughout Saturday. A second round of precipitation on Sunday could introduce freezing rain and ice pellets further south, affecting areas like Elliot Lake, Sudbury, and North Bay. Snowfall totals in Northeastern Ontario are expected to range from 20 to 30cm, making travel difficult.

Even the Ottawa Valley will see significant snowfall, with up to 20cm possible, along with a mix of ice pellets. By Sunday, freezing rain could become a concern for the region as temperatures rise and the precipitation type shifts.

As of Friday afternoon, rain is already moving into Southwestern Ontario. By the evening, precipitation will spread north and east into Central and Eastern Ontario.

Based on the latest data, a band of heavy snow is expected to develop along a corridor stretching from Sudbury through North Bay and into the Ottawa region. To the south, an area of freezing rain will form over the Bruce Peninsula and extend into regions around Lake Simcoe.

**ESTIMATED TEMPERATURE** - MAP FROM WEATHERBELL

How far south the freezing rain spreads remains uncertain. Model guidance suggests surface temperatures will hover near the freezing mark across Barrie and the Greater Toronto Area (GTA).

Even a fraction of a degree difference could significantly alter how much freezing rain accumulates. If the air remains colder than expected, freezing rain could be more widespread. However, a slightly warmer scenario would push the freezing rain line further north.

Confidence is highest for freezing rain in northern sections of Simcoe County, Kawartha Lakes, and Muskoka. These areas are most likely to remain below freezing for an extended period, allowing heavy ice accretion to build up.

The most intense icing is expected overnight into early Saturday morning. The worst conditions will stretch from Muskoka through Peterborough and into Kingston.

Once again, temperature will be the deciding factor. Some areas, such as Barrie and Newmarket, sit right on the edge between freezing rain and regular rain. If cold air lingers longer than anticipated, freezing rain could extend as far south as the northern GTA, as well as higher elevations like the Dundalk Highlands.

Through Saturday morning and afternoon, light to moderate freezing rain or drizzle is expected to persist across portions of Central Ontario, particularly around Lake Simcoe. However, the intensity will decrease compared to the earlier hours.

Further south, rain will continue across Southwestern Ontario and the GTA. This is when we expect the warmest temperatures of the storm. Some areas in Deep Southwestern Ontario, including Windsor, could surge into the 20s, while Central Ontario remains near or below freezing.

By Saturday evening, another round of heavy precipitation is expected to push into Central Ontario. At the same time, temperatures will steadily drop. Regions that saw rain in the afternoon—including parts of the GTA and Barrie—may transition back to freezing rain.

Model data suggests that by late Saturday night into Sunday morning, the freezing rain line could shift southwest of the GTA. This could result in several hours of freezing rain across Kitchener, Waterloo, and parts of the Toronto area.

Deep Southwestern Ontario, including Windsor, Sarnia, and London, is expected to remain unaffected, staying well above freezing.

Sunday morning will bring a gradual transition from freezing rain to regular rain across the GTA as temperatures climb above freezing. However, elevated areas northwest of the city, such as Guelph, Orangeville, and Shelburne, could see freezing rain linger for a few extra hours.

For Central Ontario, the freezing rain will continue into early Sunday afternoon as the main area of precipitation slowly shifts north.

By Sunday afternoon, the Ottawa Valley may begin transitioning from snow to ice pellets and then to freezing rain as temperatures rise.

Most of Southern Ontario will warm above the freezing mark by late Sunday, finally pushing the freezing rain threat northward.

However, by Sunday night into Monday morning, the risk of freezing rain will shift to Northeastern Ontario, including Sudbury and North Bay.

Meanwhile, heavy snow and ice pellets will impact more northern regions, such as Wawa and Timmins.

Predicting exact ice accretion remains challenging, as many factors influence how much ice actually builds up. The amount of freezing rain you experience may vary significantly from nearby areas due to microclimate effects, surface conditions, and temperature fluctuations.

Some high-resolution model runs suggest an extreme scenario with localized pockets of over 50mm—possibly even 75mm—of freezing rain. However, because much of this precipitation will fall in a relatively short timeframe, not all of it will necessarily adhere to surfaces.

Given this, we are forecasting general ice accretion between 25 and 40mm in the hardest-hit areas. This includes the northern tip of the Bruce Peninsula, Muskoka, Orillia, Barrie, Orangeville, Collingwood, Lindsay, Peterborough, Belleville, and Kingston.

If temperatures are slightly colder than expected, some locations could exceed 40mm of ice accretion, particularly where conditions allow for more efficient accumulation.

ice storm safety tips

To put this into perspective, we can use the Sperry-Piltz Ice Accumulation Index (SPIA Index). With forecasted ice accumulations of 25-40mm (1-1.4”), this storm falls into a Category 4 ice event—even before factoring in wind.

While we are not expecting extreme winds, gusts of 40-50km/h (25-30 mph) in some areas could push this storm into Category 5 territory. According to the SPIA Index, a Category 5 ice storm results in:

Catastrophic damage to entire exposed utility systems, including both distribution and transmission networks. Outages could last several weeks in some areas. Shelters needed.

For the Greater Toronto Area (GTA), ice accretion amounts will vary significantly. The biggest factor will be how long cold air remains trapped at the surface.

We currently expect between 10-15mm of ice for northern parts of the GTA, including York, Durham, and Peel regions. Kitchener and Waterloo will likely see between 5-10mm.

Closer to the Lake Ontario shoreline—including downtown Toronto—freezing rain amounts should be lower, around 2-5mm. However, if temperatures are colder than expected, ice accretion in the GTA could be higher, so it’s still best to prepare.

To the north, ice accretion amounts will drop off as freezing rain transitions to ice pellets and snow closer to the Ottawa Valley.

In terms of snowfall, widespread totals between 20-30cm are expected across much of Northeastern Ontario through Monday. This includes Sudbury, North Bay, Chapleau, Timmins, and Kirkland Lake. Even Thunder Bay could see 10-20cm of snow, mainly earlier in the weekend.

Along the Quebec border, snowfall amounts will range from 10-20cm in areas like the Ottawa Valley and Cornwall. Further southwest, freezing rain and ice pellets will be the dominant concern, leading to lower snowfall totals.

This storm remains highly dynamic, with small temperature fluctuations potentially making a massive difference in what type of precipitation falls. We will continue to monitor the latest data and provide updates as the situation evolves. Stay safe and stay prepared.

March 26, 2025

Potential Major Ice Storm Threat on the Horizon for Southern Ontario This Weekend

March 26, 2025/ Brennen Perry

With the end of March approaching and the arrival of April, winter’s grip on Southern Ontario is loosening. However, Old Man Winter isn’t leaving quietly. Instead, the final days of March bring the potential for multiple rounds of heavy freezing rain across parts of the region.

The risk of freezing rain is set to begin late Friday as the first wave of precipitation moves in. This initial bout of freezing rain could be quite heavy at times, particularly across Central and Southern portions of Eastern Ontario. The Greater Toronto Area (GTA) may also see some freezing rain late Friday before transitioning to regular rain as temperatures rise overnight.

A second wave of freezing rain is expected to develop Saturday evening and continue through Sunday. However, this round carries more uncertainty, with forecast models disagreeing on how far north warm air will push at the surface. Some models concentrate the freezing rain in Northeastern Ontario and the Ottawa Valley, while others bring it much farther south, placing the GTA in the bullseye.

While there is still uncertainty regarding the exact track and intensity of the freezing rain, all major weather models agree on the overall setup. Cold air will remain locked in at the surface across parts of Southern Ontario, while a surge of warm air moves in aloft. This combination will create ideal conditions for freezing rain formation.

These conditions are expected to persist throughout much of the weekend, with multiple waves of freezing rain possible. Given the prolonged duration of freezing rain, significant impacts are likely. Thick layers of ice could accumulate on untreated surfaces, including trees and power lines. The weight of this ice may lead to substantial damage to the power grid, with outages that could take days—or even weeks—to repair.

Focusing on the first round, models are beginning to develop a clearer picture of where freezing rain will be most intense. Initial bands of precipitation should move into Southwestern Ontario by late Friday afternoon or evening.

As this precipitation reaches areas such as Kitchener, Owen Sound, and Barrie, it will encounter stubborn below-freezing temperatures at the surface. This will lead to freezing rain developing across these regions.

Further north, a band of heavy snow is expected to spread across areas near the northern shoreline of Lake Superior, extending into Timmins. In more southern locations, such as Sault Ste. Marie, Sudbury, and North Bay, ice pellets will likely be the dominant form of precipitation.

Models agree that warm air associated with this system will gradually work its way toward the surface, beginning in the southwest and pushing northeast through the night. As a result, some freezing rain may mix with regular rain, especially southwest of Lake Simcoe and near the Lake Ontario shoreline in the GTA.

The persistence of cold air at the surface remains a major question mark. Some models suggest that cold air will be more stubborn, leading to more sustained freezing rain in the GTA overnight and into Saturday morning.

What is more certain is that a particularly intense band of freezing rain will set up over Central Ontario, including the Bruce Peninsula, Muskoka, Simcoe County, Peterborough, and Kingston. Significant ice accumulation is expected in these areas, with freezing rain continuing into Saturday morning. While freezing rain will persist into the afternoon, it should gradually become more scattered in nature.

In the Ottawa Valley, ice pellets and snow will be the main concern. There remains uncertainty regarding snowfall totals, as accumulation will depend on how much mixing occurs with ice pellets. Estimates currently range from 10 to 20 cm, but if ice pellets dominate, snowfall amounts could be closer to 5 cm.

Looking at the temperature setup for this event, a sharp gradient will be present across Southern Ontario on Saturday morning. This is one of the factors making this forecast so tricky.

Below-freezing temperatures will be well-established over Central and Eastern Ontario, as indicated by areas northeast of the pink line on the map above. Meanwhile, Deep Southwestern Ontario—including Windsor, Sarnia, and London—will experience double-digit temperatures, with no threat of wintry precipitation.

The most uncertain area lies between the orange and pink lines on the map above. This includes much of the GTA and the Grey-Bruce region. Temperatures in these areas will hover near the freezing mark, placing them at the boundary between warm and cold air. If models are off by just a degree or two, it could mean the difference between an ice storm and plain rain.

This represents our preliminary assessment of the hardest-hit areas from the first round of freezing rain. It’s important to note that this forecast covers conditions through Saturday night, but the threat of freezing rain will persist into Sunday and even Monday. There is less certainty regarding how the second round will play out, so our focus remains on the first round for now.

Confidence is highest for significant ice storm impacts in locations such as Tobermory, Wiarton, Owen Sound, Collingwood, Orangeville, Barrie, Midland, Orillia, Muskoka, Parry Sound, Peterborough, and Kingston. Ice accretion in these areas will likely exceed 10 mm and could even reach 20 to 30 mm in the worst-case scenarios.

As previously discussed, temperatures will play a crucial role in determining the extent of freezing rain along the narrow corridor that includes the GTA and Kitchener. Slightly colder temperatures could mean prolonged freezing rain, while a warmer solution would allow for a quicker transition to rain overnight Friday.

Those in Deep Southwestern Ontario and along the Lake Erie shoreline should see little impact, as temperatures will remain well above freezing, resulting in plain rain rather than freezing precipitation.

For more northern regions along the Quebec border, ice pellets and snow will be the dominant precipitation types. Locations such as North Bay, Pembroke, and Ottawa could see 10+ cm of snow, with a risk of ice pellets and possibly brief periods of freezing rain.

As the first round of freezing rain winds down across Southern Ontario, lingering pockets of freezing drizzle may persist across Central and Eastern Ontario through Saturday afternoon. In the GTA, temperatures could dip just enough to allow for a transition back to freezing rain later in the day.

The second round of freezing rain is expected to arrive by Saturday evening as energy moves in from the U.S. Midwest.

Models are in solid agreement that this second wave will set up another band of freezing rain in the same areas hit hardest by the first round, including Central Ontario and portions of the GTA. This freezing rain will persist overnight into Sunday morning. However, by Sunday morning, the models begin to diverge significantly.

A more northern track would see warm air winning out across Southern Ontario, allowing temperatures to rise and leading to a transition to rain near Lake Simcoe. This would push the freezing line northward into Northeastern Ontario and the Ottawa Valley. In this scenario, freezing rain would be confined to areas such as Sudbury and North Bay, while heavy snow would develop from Wawa to Timmins.

Both the Canadian and European models favor this northern solution, which would be the better outcome for Southern Ontario, as it would avoid a second major icing event. However, this would be worse news for Sudbury and North Bay, where a significant ice storm could unfold.

This more northern track has the warmer air winning out across Southern Ontario during the morning on Sunday. This gradually leads to a switch over to rain near Lake Simcoe as the freezing line puches north into Northeastern Ontario and the Ottawa Valley.

Then freezing rain would be contained to Northeastern Ontario including Sudbury and North Bay. While heavy snow extends from Wawa to Timmins.

Both the Canadian and European models favor this solution. Which would certainly be the better outcome for Southern Ontario as they escape a second icing event. But would be worst news for Sudbury and North Bay which could see an ice storm.

On the other hand, the American model suggests a much more southerly track, which would place Southwestern Ontario and the Golden Horseshoe directly in the path of heavy icing. This scenario would bring freezing rain through Sunday night into Monday morning, creating hazardous conditions for the Monday morning commute.

If this outcome materializes, widespread school bus cancellations across Southern Ontario would be likely on Monday morning. Meanwhile, areas farther north could see accumulating snow on top of earlier ice buildup.

Unfortunately, a significant cooldown is expected in the wake of this storm. By Monday evening, temperatures will plunge into the negative teens. Any ice that accumulates over the weekend will remain in place for several days, increasing the strain on the power grid as trees continue to fall onto power lines.

Regardless of how this storm unfolds, it is shaping up to be a high-impact winter event with potentially severe consequences in some areas. Prepare for treacherous travel conditions and the possibility of widespread power outages lasting multiple days.

We will provide further updates as the weekend approaches. Stay tuned and stay safe!

March 16, 2025

First Isolated Severe Thunderstorm Risk of the Season for Parts of Southern Ontario Sunday Afternoon and Evening

March 16, 2025/ Adam Skinner

It’s certainly been a while since we’ve had an isolated risk for severe thunderstorm activity in Southern Ontario, but here we are! Welcome to Spring! What we’re expecting is a line of thunderstorms and based on the time I’m writing this (11:11am), it looks like it has already begun to develop over Lake Erie. This line will continue to push to the northeast, affecting the Niagara Region and potentially all the way up to Barrie and parts of Simcoe County.

**RADAR IMAGE FROM 11:12 AM EDT** - MAP FROM INSTANTWEATHER PRO

Taking a look at the IW Pro app screenshot above, you can see the thunderstorm line beginning to develop over Lake Erie. We’re expecting nickel-size hail (perhaps a bit larger), strong wind gusts, torrential rain and frequent lightning with this line. Additionally, you can see a red outline of a Tornado Watch south of the border that covers areas south of Lake Erie.

An isolated tornado cannot be entirely ruled out with this system slipping past the international border and tracking into Ontario, so we’ll be keeping a very close eye on radar today. If you don’t already have our free app, InstantWeather, today may be a good day to download it so we can notify you of any rotating storms, funnel cloud reports or Environment Canada alerts.

Some models have also shown some very intense wind gusts, potentially exceeding 100km/h, especially in eastern Ontario, so we’re fairly concerned with that potential. Being an early season event, we decided to go with a Marginal (green) risk, but there certainly is a chance these storms could exceed the Slight (yellow) threshold, especially with the wind risk.

**MAX WIND GUST FORECAST FROM THE HRRR MODEL** - MAP FROM WEATHERBELL

In the image above, we see the HRRR model’s maximum wind gust forecast for Southern Ontario, showing some very strong winds in yellow and orange. This is just one model’s output so it’s not a guarantee. Nonetheless, if wind gusts do reach these levels, even in isolated areas, we could end up seeing some fairly strong wind damage to trees, hydro polls or perhaps even structures.

The main risk, timing wise, should begin this afternoon in the Niagara Region, with storms moving northeast from Lake Erie and that risk should continue to spread northeast into the evening hours. Generally, our main concern is for Niagara and areas north and east of Lake Ontario into eastern Ontario. However, we have highlighted parts of Southwestern Ontario, the GTHA, and Central Ontario as well, as we’ve seen some model data suggesting strong wind gusts are possible in those regions, along with hail, torrential rain, isolated flooding, frequent lightning and a small risk of an isolated tornado.

In general, the tornado risk is quite isolated. Having said that, with a potent system south of the border, there is always a chance we could see some tornado activity sneak into Ontario and based on some of the model data we’ve seen over the past couple of days, the risk of a spin-up or two cannot be ruled out.

We do plan on doing a livestream if storms continue to look strong this afternoon and evening so make sure to subscribe to our YouTube channel in order to get notified if and when we go live!

We’ll be posting more updates to our social media pages as well so if you’re on Facebook, you can find us at Ontario Storm Watch. We also have a fantastic storm reporting group on FB with Ontario Storm Reports. And if you’re on X/Twitter, you can find us at @IWeatherON.

More details ASAP and stay safe today, folks!

- Adam

February 14, 2025

Intense Snowstorm Could Bring Blizzard Conditions and Up to 30-60cm of Snow to Southern Ontario This Weekend

February 14, 2025/ Brennen Perry

The snowy weather isn’t letting up as yet another winter storm takes aim at Southern Ontario over the Family Day long weekend. This system will arrive in multiple waves, beginning Saturday and continuing through Sunday. By the time it moves out late Sunday, much of Southern Ontario could be buried under as much as 60 cm of snow.

Strong winds will develop throughout Sunday morning into the afternoon, with gusts reaching 50 to 80 km/h in some areas. These powerful winds, combined with heavy snowfall, will create dangerous whiteout conditions and may even reach blizzard criteria. Travel is expected to become difficult as early as Saturday morning, with conditions steadily worsening through the night and into Sunday.

The most hazardous conditions are expected Sunday morning and afternoon, as intense snowfall rates are combined with strong wind gusts, making all non-essential travel extremely dangerous. Highway closures are highly likely in the hardest-hit regions as plows struggle to keep up with rapid snowfall rates, while blowing and drifting snow significantly reduces visibility.

There is still some uncertainty regarding the storm's exact track, which will determine where the heaviest snowfall occurs. Areas along the Lake Erie shoreline and possibly parts of the Golden Horseshoe could see periods of freezing rain or ice pellets by late Sunday morning. While this would create its own hazards, any mixing would also lower overall snowfall totals.

As of now, Eastern and parts of Central Ontario appear to be in line for the highest snowfall amounts. Combined two-day snowfall totals could range from 30 to 60 cm by Sunday night, with 5-10 cm expected on Saturday and an additional 25-50 cm possible on Sunday.

**HOURLY SNOWFALL RATE/intensity** - MAP FROM WEATHERBELL

The storm will get underway Saturday morning as steady snow moves into Deep Southwestern Ontario from Michigan. It will spread into London and the Greater Toronto Area (GTA) by late morning. Some light flurries may reach Central and Eastern Ontario, but the more persistent snowfall will remain south of Lake Simcoe.

At this stage, conditions may not seem too severe, leading to the false impression that the storm has been overhyped. However, don’t be fooled—snowfall rates will gradually increase through the afternoon, reaching 1-2 cm per hour and steadily accumulating.

By mid-afternoon Saturday, light to moderate snowfall will have spread across most of Southern Ontario. The heaviest snowfall will be concentrated over Southwestern Ontario and the GTA, while Central and Eastern Ontario, including the Ottawa Valley, may only see scattered flurries.

There are indications that parts of Deep Southwestern Ontario—including Windsor, Chatham, and possibly London—may see a transition to ice pellets or freezing rain. Meanwhile, Kitchener, Hamilton, and the GTA should remain primarily snow.

Heading into the evening, the storm’s moisture supply will intensify as it taps into the Gulf of Mexico, keeping snow steady across Southern Ontario. However, Central and Eastern Ontario may experience more scattered snowfall during this time. The most persistent snow bands are expected to set up along the Windsor-London-Hamilton corridor.

Some mixing could still occur near the Lake Erie shoreline, particularly in Leamington and the southern Niagara region, though it remains uncertain how far inland it may extend. If the mixing line pushes north, areas such as Windsor could also see freezing rain.

By the end of Saturday, snowfall totals are expected to range from 5 to 10 cm across much of Southern Ontario, with locally higher amounts of up to 15 cm in areas benefiting from lake enhancement like Southwestern Ontario and the Golden Horseshoe.

Eastern Ontario and the Ottawa Valley will see lower totals, between 2 and 5 cm, as the first wave of snow stays focused farther south.

Conditions will deteriorate rapidly overnight Saturday as even more moisture-laden precipitation moves in from Michigan. Snowfall rates will increase during the pre-dawn hours, starting in the southwest around midnight before progressing east and north through the morning.

There remains some disagreement among forecast models regarding the extent of mixing along the Lake Erie shoreline, but there is a possibility of significant ice accretion in parts of Windsor and the Niagara region.

By late Sunday morning, the system is expected to intensify rapidly as the low-pressure center tracks south of the Great Lakes. This intensification will result in significantly higher snowfall rates, especially in the GTA, Niagara region, and Central Ontario, including Barrie, Muskoka, and Peterborough.

Snowfall rates could reach 5-10 cm per hour, making it impossible for road crews to keep up. Eastern Ontario and the Ottawa Valley will see steady snow increase throughout Sunday afternoon and into the early evening.

Adding to the severity of the storm, strong wind gusts of 50-80 km/h will develop through Sunday morning, with the highest gusts expected in Central and Eastern Ontario. These winds, combined with intense snowfall rates, will almost certainly lead to blizzard conditions in some areas.

Visibility will be near zero, with blowing and drifting snow making travel dangerous. All non-essential travel should be avoided on Sunday morning and afternoon, as highway closures are likely in the hardest-hit regions. With snow falling at rates of 5-10 cm per hour, it will be extremely easy to become stranded, as plows will struggle to keep roads passable.

Despite being less than 48 hours away, there is still some uncertainty in the storm's track and timing. Different forecast models continue to show varying scenarios, which could impact snowfall totals and the extent of mixing.

The short-range American model (HRRR), which provides detailed hourly forecasts, aligns closely with the Canadian and European models. These models suggest a more southern track, keeping the GTA and much of Southern Ontario primarily in the snow zone.

However, another American model (NAM) suggests a more northern track with a later arrival. If this scenario plays out, the mixing line would shift farther north, bringing ice pellets or freezing rain from London to Hamilton and into the GTA. This would reduce snowfall totals in these areas but create hazardous icy conditions.

This model also suggests the mixing could extend along the Lake Ontario shoreline into parts of Southeastern Ontario, including Belleville, Kingston, and Brockville. While this scenario is less likely, it’s still worth monitoring.

Additionally, the NAM model points to a significant icing event for Hamilton and the Niagara region, with potential ice accretion of 10-15 mm. If this happens, localized power outages and tree damage could occur.

The model also suggests that while some forecasts indicate the heaviest snow will arrive early Sunday, this scenario shifts the worst conditions to the afternoon in Southwestern Ontario and the GTA, extending into the evening for Eastern Ontario.

Regardless of the final track, conditions should improve as snow tapers off from west to east late Sunday evening, with lingering snow in Eastern Ontario into early Monday morning. However, lake-effect snow could quickly develop around Lake Huron and Georgian Bay as the system exits.

By the time this storm is over, a wide swath of Eastern and Central Ontario could see 30-60 cm of fresh snow, including the accumulation from both Saturday and Sunday.

For Southwestern Ontario and the GTA—including Sarnia, London, Kitchener, Hamilton, and Toronto—snowfall totals will likely range from 20-40 cm. However, if mixing occurs on Sunday, snowfall amounts could drop to 15-30 cm or even lower, depending on how extensive the ice pellets or freezing rain become.

The lowest snowfall totals will likely be in Deep Southwestern Ontario and along the Lake Erie shoreline, where freezing rain and ice pellets will reduce overall accumulation. Areas such as Windsor, Leamington, Chatham, St. Thomas, and Niagara Falls could see between 15-30 cm of snow, depending on how much mixing occurs.

We are closely monitoring the latest forecast data and will provide a more detailed breakdown of Sunday’s snowfall totals in an updated forecast on Saturday. Stay tuned for further updates.

February 11, 2025

High Impact Winter Storm on the Way for Southern Ontario Starting Wednesday With Up to 40cm of Snow & Freezing Rain

February 11, 2025/ Brennen Perry

Confidence is growing that Southern Ontario is on track for what could be the most widespread and significant winter storm of the season so far. That said, there hasn’t been much competition in that regard, as most of this winter’s snowfall has come from localized snow squalls. However, a shift in the weather pattern has placed the region in an active storm track, and Mother Nature isn’t wasting any time delivering a disruptive winter storm right in the middle of the week.

Earlier, there was some uncertainty regarding the exact track of the system, which would have influenced snowfall amounts in different areas. However, in the past 24 hours, forecast models have begun to align on a more consistent storm track. Interestingly, the latest data supports what we initially projected, meaning there hasn’t been a major shift in the forecast.

Widespread snowfall accumulations of 20 to 40 cm are expected from Southwestern Ontario through Central Ontario and into the Ottawa Valley between Wednesday and Thursday. In the Golden Horseshoe and Deep Southwestern Ontario, precipitation will likely begin as snow, but there is potential for ice pellets, freezing rain, or even regular rain to mix in. This could limit snowfall totals, especially along the shorelines of Lake Ontario and Lake Erie, where temperatures may hover near the freezing mark.

For the Greater Toronto Area (GTA), the extent of mixing remains a key uncertainty. It could go either way. Right now, we’re forecasting 10 to 20 cm of snow, but if the mixing line stays south, snowfall amounts could surpass expectations, reaching 25 to 30 cm.

In Deep Southwestern Ontario, including Windsor, Chatham, and extending into the Niagara region, models suggest several hours of freezing rain Wednesday evening and overnight. Some localized areas could see ice accretion of 2 to 5 mm, leading to slippery, untreated surfaces and hazardous road conditions.

The storm is expected to arrive Wednesday afternoon, with scattered precipitation moving into Southwestern Ontario between 2 and 4 PM. While most areas will initially see snow, some models are aggressive in bringing freezing rain into Windsor and Chatham by late afternoon.

Before the main storm arrives, lake-effect snow may develop off Lake Ontario, affecting the Burlington and Hamilton corridor Wednesday morning into early afternoon. System snow should reach the GTA just before the evening rush hour, making for a difficult commute.

The latest model data has also increased wind projections, with gusts of 40 to 60 km/h in some areas. Combined with heavy snowfall, this could lead to blowing snow and reduced visibility. Non-essential travel should be avoided starting in the late afternoon, with conditions deteriorating further into the evening.

By mid to late evening, snow will have spread across most of Southern Ontario, including Central and Eastern Ontario. A key feature to monitor will be the movement of the mixing line.

Current data shows a freezing rain corridor stretching from Leamington through Chatham and along the Lake Erie shoreline, with a narrow band of ice pellets from Windsor through just south of London and into Hamilton.

Meanwhile, heavy snow will persist across Sarnia, London, Kitchener, and the GTA. Snowfall rates will intensify after 9–10 PM, increasing from 1–2 cm per hour to 2–4 cm per hour. This will make it challenging for snowplows to keep up.

After midnight, the mixing line may push north into parts of the GTA, bringing ice pellets and freezing rain to locations such as London, Burlington, Mississauga, and Toronto for several hours. However, this transition looks to be confined near the Lake Ontario shoreline, meaning snowfall will likely dominate farther inland.

Freezing rain will continue across Windsor and along the Lake Erie shoreline into the Niagara region, while heavy snow steadily blankets Central and Eastern Ontario overnight.

The system will begin its exit Thursday morning, with snow tapering off in Southwestern Ontario first. However, snow will continue across Central and Eastern Ontario.

In the Niagara region and along the Lake Ontario shoreline, mixing will remain a concern into the early morning hours. However, by 4–6 AM, colder air will push in, flipping precipitation back to snow. Any previously fallen precipitation may refreeze as temperatures drop, creating hazardous road conditions.

Expect treacherous travel conditions on Thursday morning. Roads will be slushy and icy in areas that saw mixing, while heavy snow will make roads impassable further north. Widespread school bus cancellations and school closures are likely.

Eastern Ontario will hold onto light to moderate snow through the late morning. However, models indicate some potential for mixing in the Kingston, Brockville, and Cornwall areas. This could result in light icing from freezing rain before a final transition back to snow.

Most of Southern Ontario will finally see an end to precipitation Thursday, aside from some lingering lake-effect snow near Lake Huron.

Based on the latest data, the highest snowfall totals will likely be in Central and Eastern Ontario. A widespread 20–40 cm is forecast across Southwestern, Central, and Eastern Ontario. However, totals closer to 40 cm are most probable in Eastern Ontario, including Ottawa, where there’s even a slight chance of locally exceeding 40–50 cm.

Central and Southwestern Ontario, including Grey-Bruce, Kitchener, York Region, Simcoe County, Muskoka, and Peterborough, will likely receive 20–30 cm, with some areas near Lake Simcoe potentially exceeding 30 cm.

The exception will be the Lake Ontario shoreline and the International border, including Kingston, Brockville, and Cornwall. Lower snowfall ratios and a higher risk of mixing could keep totals below 20 cm. However, if mixing remains minimal, this area could exceed forecasts.

The snowfall forecast becomes more uncertain in Deep Southwestern Ontario and the Golden Horseshoe, where multiple factors create a ‘boom or bust’ scenario. The GTA will start with heavy snow, likely reaching 10 cm fairly easily unless there’s a drastic shift in the storm track. The big question is how much more accumulates beyond that.

Some models suggest that if mixing does not occur, parts of the GTA could see 20–30 cm by Thursday morning. However, given the likelihood of overnight mixing, we expect totals to stay below 20 cm, which is why our official forecast remains at 10–20 cm.

London and Sarnia sit on the boundary between significant snow and mixed precipitation. The most probable outcome is 15–20 cm, though an overperformance remains possible.

In Deep Southwestern Ontario and the Niagara region, snowfall amounts will be lower, with less than 10 cm expected. However, these areas will likely see prolonged freezing rain, with the heaviest ice accretion along the Lake Erie shoreline.

Models vary on how intense the freezing rain will be. Some project as much as 10 mm of ice accretion, but this seems unlikely given the presence of mixed precipitation and the relatively short duration of freezing rain. Our official forecast calls for 2–5 mm of ice accretion, though isolated pockets could see 7–10 mm if freezing rain persists longer than expected.

February 11, 2025

Major Winter Storm on Track to Dump Up to 40cm of Snow Across Most of Southern Ontario Starting Wednesday

February 11, 2025/ Brennen Perry

Get your shovels ready, Southern Ontario! What many would consider our first true winter storm of the season is on the horizon. This moisture-laden system is set to arrive Wednesday afternoon, bringing heavy snowfall across a large portion of our region.

There’s still some uncertainty in the exact track, which will determine who sees the heaviest snow, but confidence is growing that much of Southern Ontario will experience significant impacts from this storm. Travel will likely become hazardous Wednesday evening into Thursday morning, and widespread school bus cancellations—and even full school closures—are almost certain on Thursday.

Based on the latest data, the heaviest snowfall is expected to stretch from Southwestern Ontario through Central Ontario and into the Ottawa Valley. Accumulations will likely range between 20 to 40 cm, with some localized pockets potentially exceeding 40 cm by the time the snow tapers off early Thursday afternoon.

The most challenging part of this forecast comes down to a narrow corridor from London through Hamilton, into the Greater Toronto Area (GTA), along the Lake Ontario shoreline, and into extreme Eastern Ontario along the international border. These areas are likely to start off with snow, but depending on the storm’s track, a transition to ice pellets, freezing rain, or even regular rain could occur during the evening and overnight.

The exact snowfall amounts in this corridor remain highly uncertain, as even a fraction of a degree difference in temperature could mean the difference between 5 cm and 30 cm of snow.

The risk of freezing rain also appears significant for areas in deep Southwestern Ontario, including Windsor, Chatham, and communities along the Lake Erie shoreline, where several hours of ice accretion could result in hazardous road conditions and localized power outages.

The storm will begin impacting Southern Ontario on Wednesday afternoon, with the initial bands of snow spreading into deep Southwestern Ontario, including Windsor, Sarnia, Chatham, and London. By the mid-to-late afternoon, snow will have moved into Hamilton, Niagara, and the Greater Toronto Area, just in time for the evening commute.

Steady snowfall will continue through the dinner hour, with snowfall rates gradually increasing as the system spreads further across the region. Central and Eastern Ontario will see snow begin around the dinner hour into the early evening, while the Ottawa Valley may not see the first flakes until mid-to-late evening.

Snow will continue throughout the night across much of the region, with varying intensity. Unlike some past storms, this event isn’t expected to bring extreme snowfall rates, with accumulations of around 2 to 4 cm per hour at most. However, the prolonged nature of this storm, lasting 12 to 16 hours in many areas, will allow totals to build up significantly.

Another key factor in determining final snowfall amounts will be how far north the mixing line extends into Southern Ontario. Earlier model runs suggested a more northern track, which would allow warmer air to push into areas along the Lake Erie and Lake Ontario shorelines, leading to a transition from snow to ice pellets, freezing rain, or rain.

However, more recent model data from Monday evening has trended slightly further south, reducing the risk of mixing for some areas. That said, some models, including the American (NAM) and European models, still show a more northern mixing line, which could bring ice and rain into parts of deep Southwestern Ontario, London, and Hamilton.

If this occurs, Windsor and areas along the Lake Erie shoreline could see several hours of freezing rain, resulting in ice buildup on untreated surfaces, power lines, and roads.

On the other hand, the Canadian (RGEM) model, along with the higher-resolution American NAM 3km model, suggest a more southern storm track, which would keep most of Southern Ontario in the snow zone.

If this scenario plays out, snowfall accumulations could be much higher in places like London, Hamilton, and the Golden Horseshoe, with totals ranging from 20 to 30 cm and minimal mixing.

Some models also indicate the possibility of mixing slightly north of Lake Ontario and along the St. Lawrence River, including Kingston, Brockville, and Cornwall, which could lower snow totals in these areas. However, the latest data suggests this region may stay entirely on the snowy side of the system.

As the storm progresses overnight, those areas that remain on the snow side will continue to see accumulation through early Thursday morning. Snowfall rates could briefly reach 2 to 4 cm per hour in heavier bands but will likely average closer to 1 to 2 cm per hour.

Fortunately, winds won’t be particularly strong, with gusts expected to range from 20 to 40 km/h at most. While some blowing snow is possible, full-blown blizzard conditions are not expected with this storm.

By mid-morning Thursday, high-resolution models suggest a final burst of heavier snow around the Golden Horseshoe, Lake Simcoe, and Eastern Ontario. Snowfall rates could briefly spike to 4 to 6 cm per hour as the back end of the system moves through during the morning rush hour.

Travel conditions will likely be very poor on Thursday morning, and all non-essential travel should be avoided. Widespread school bus cancellations are almost a certainty given these conditions.

A rapid improvement is expected in Southwestern Ontario by late morning, with snowfall tapering off to light flurries. However, it will take time for road crews to clear the heavy snowfall, so road conditions may remain hazardous into the early afternoon.

For Central and Eastern Ontario, snow will linger into the early afternoon before finally winding down around midday for the GTA and Central Ontario and mid-afternoon for the Ottawa Valley.

By the time the storm wraps up, a broad region across Southern Ontario, including the Lake Huron shoreline, Sarnia, Kitchener, Barrie, Muskoka, Peterborough, and the Ottawa Valley, will likely see between 20 and 40 cm of fresh snow. Mixing is unlikely to be a factor in these areas, though there’s always a slight chance of a last-minute shift in the storm track.

The biggest uncertainty lies within a narrow corridor that includes London, Woodstock, Hamilton, Mississauga, Toronto, Belleville, Kingston, Brockville, and Cornwall. This area will likely begin with snow on Wednesday but could see ice pellets, freezing rain, or rain mix in during the late evening and overnight hours, which would reduce total snowfall amounts.

A conservative estimate for this region is at least 10 cm of snow, though some areas, particularly along the northern edge of this zone, could see totals closer to 20 to 30 cm. The current model trends lean toward a slightly more southern storm track, but we are waiting to see if this pattern holds before making final adjustments to the snowfall forecast.

For Windsor, Chatham, and areas along the Lake Erie shoreline, including Niagara, a mix of snow and freezing rain is expected. Some locations could experience several hours of freezing rain, leading to ice accretion of 4 to 8 mm, which may cause localized power outages. However, if the mixing line remains further south, these areas could still end up seeing significant snowfall, possibly exceeding 20 cm.

The bottom line is that while we have high confidence in a significant winter storm, the local impacts will ultimately depend on the storm’s exact track, which may not become fully clear until just before the system moves in.

A more detailed forecast with refined snowfall and freezing rain estimates will be released late Tuesday as newer model data becomes available.

February 04, 2025

Wintry Mix of Snow, Sleet and Freezing Rain Threatens Thursday Morning Commute Across Southern Ontario

February 04, 2025/ Brennen Perry

A shift in the weather pattern across Southern Ontario over the past few days has brought a noticeable retreat from the extreme cold, with temperatures returning to near-seasonal values. However, this shift has also placed the region on a more active storm track, a pattern we first experienced with Monday’s messy system.

The next round of unsettled weather was initially showing signs of a prolonged freezing rain event on Thursday. However, recent model trends indicate a significantly weaker system than previously expected. While this storm will still impact Southern Ontario, the main threat now appears to be light freezing rain and snow, particularly during the Thursday morning commute.

Although snowfall totals won’t be overly impressive, Central and Eastern Ontario could see an average accumulation of 4 to 8 cm by the end of the day. The primary concern will be the mix of precipitation types, which could create slushy and icy road conditions, making for a slick and potentially hazardous commute.

Looking ahead to the weekend, we are closely watching a moisture-laden system that could bring Southern Ontario its first true widespread snowstorm of the season. This storm has the potential to impact even those regions that have largely avoided significant snowfall so far, including Deep Southwestern Ontario and the Golden Horseshoe.

Current projections suggest snowfall totals could range from 10 to 25 cm, though these estimates will likely be refined as we get closer to the event.

**PRECIPITATION TYPE OVER LAST 6 HOURS** - MAP FROM WEATHERBELL

Thursday’s system is expected to begin during the morning hours as light precipitation moves in from the southwest. High-resolution models, such as the American model shown above, suggest that the precipitation will be quite scattered with dry pockets throughout. However, if the precipitation takes the form of light flurries or drizzle, some models may be underestimating its extent.

For Central and Eastern Ontario, precipitation will likely fall as snow. Across the Golden Horseshoe, it may also start as snow during the mid-morning hours before transitioning. Meanwhile, areas along the Lake Erie shoreline and Deep Southwestern Ontario will be more prone to freezing rain and ice pellets from the onset.

Travel conditions could become challenging, particularly in the morning as freezing rain coincides with rush hour across Southwestern Ontario and into the Golden Horseshoe.

At this point, it’s uncertain whether this system will be strong enough to prompt widespread school bus cancellations. However, the highest risk for disruptions will be in Windsor, Chatham, and London, where precipitation is expected to begin earlier in the morning with a higher likelihood of freezing rain.

By early afternoon, precipitation should become more widespread, particularly in Central and Eastern Ontario, as drier areas fill in with moisture. Despite this, snowfall rates are expected to remain manageable, likely staying under 1 cm per hour. However, snow could persist for a solid 6 to 8 hours through the late morning and afternoon, leading to gradual accumulation.

Meanwhile, the freezing rain threat will begin expanding toward Hamilton and the western GTA, with ice pellets potentially mixing in as the transition from snow to freezing rain occurs.

Gradually, precipitation will taper off in Deep Southwestern Ontario, with lingering drizzle as temperatures slowly rise above freezing. This slight warm-up will help melt any ice accretion from earlier in the day.

Across the rest of Southern Ontario, precipitation should wind down by late afternoon or early evening. In the wake of the system, some minor lake-effect snow may develop around Georgian Bay and Lake Huron, but we are not expecting any organized lake-effect activity at this time.

While Thursday’s system may be relatively minor, it could serve as a precursor to a much more impactful storm set to arrive this weekend.

Uncertainties remain, and details could shift as we get closer to Saturday. However, all major weather models continue to signal a strong system targeting Southern Ontario late Saturday into Sunday.

The exact track and intensity will determine which areas see the most significant impacts. At this point, current projections suggest a prolonged freezing rain threat for Deep Southwestern Ontario and areas along the Lake Erie shoreline. Meanwhile, heavy snow, with potential accumulations between 10 and 25 cm, could affect parts of the Golden Horseshoe, Central Ontario, and Eastern Ontario.

Again, this forecast is subject to change, but this storm has the potential to be a high-impact event for much of Southern Ontario. Stay tuned, as we’ll be providing more detailed updates in the coming days!

January 26, 2025

Damaging Wind Storm Sweeps Into Ontario With Gusts Over 90 km/h and Blizzard Conditions on Monday

January 26, 2025/ Brennen Perry

The final week of January is shaping up to start with turbulent weather across Southern Ontario, as a damaging windstorm is set to impact the region on Monday.

Wind gusts are forecasted to reach 80 to 90 km/h across much of Southern Ontario during the day on Monday, with some localized pockets potentially seeing gusts exceeding 100 km/h.

Power outages are a significant concern for the hardest-hit regions, along with other types of wind-related damage, such as fallen tree branches and unsecured objects being blown around. In addition, the strong winds may create another hazard along the Great Lakes shoreline, where ice could be pushed ashore, causing damage to property along the lakes.

Adding to the danger, a sharp cold front is expected to sweep through Ontario over the next 24 hours, bringing a blast of wintry weather, including an intense frontal snow squall. Combined with the strong winds, some areas could experience blizzard-like conditions starting late Monday afternoon and lasting into the evening.

While this event isn’t expected to bring significant snowfall totals to Southern Ontario, accumulations could range from 5 to 15 cm, depending on the location.

However, areas east of Lake Superior in Northern Ontario may see higher amounts, with localized totals reaching 20 to 30 cm, while a broader area of Northeastern Ontario is expected to receive 10 to 20 cm.

The windstorm is expected to begin early Monday morning across Southern Ontario, with wind speeds gradually increasing through mid-morning.

Southwestern Ontario, particularly areas along the Lake Huron shoreline, will experience the strongest winds first, around sunrise. These conditions will then spread east and north by early afternoon.

The strongest winds are anticipated during the early to mid-afternoon hours, with widespread gusts ranging from 70 to 90 km/h across the region.

Areas such as the Dundalk Highlands, Niagara region, Northern Lake Erie shoreline, and Prince Edward County could see slightly higher wind gusts due to their exposure to the lakes and elevated terrain. Gusts in these areas may exceed 100 km/h, possibly reaching 105 to 110 km/h near Collingwood along the Georgian Bay shoreline.

Other locations, including Goderich, Kincardine, Owen Sound, Wiarton, Tobermory, Guelph, Kitchener, Hamilton, Brantford, Britt, Parry Sound, Belleville, Kingston, and Brockville, could experience wind gusts between 90 and 100 km/h. This range represents the greatest potential for wind damage, including localized power outages.

The remainder of Southern Ontario—excluding Deep Southwestern Ontario and the Ottawa Valley—can expect gusts between 80 and 90 km/h, with occasional stronger gusts. Deep Southwestern Ontario and the Ottawa Valley are likely to see slightly weaker winds, with maximum gusts of 70 to 80 km/h.

For those with properties along the Great Lakes, particularly Lake Erie, the risk of ‘ice shoves’—where winds push broken ice onto shore—is a concern. This phenomenon can cause significant damage and flooding along the shoreline. Residents in affected areas should prepare for this potential over the next 24 hours.

Wind speeds are expected to diminish somewhat later in the afternoon and into Monday evening, though they will remain strong, ranging from 60 to 90 km/h. This coincides with the arrival of a pocket of moderate to heavy snow in Central Ontario during the late afternoon.

The snowfall is expected to begin affecting the Parry Sound and Muskoka regions between 2:00 and 4:00 PM, leading to blowing snow and possible blizzard conditions lasting several hours into the evening.

Travel during this time will likely be hazardous, with significantly reduced visibility and potentially closed roads. While snowfall rates won’t be overwhelming, at a few centimetres per hour, the strong winds will make conditions dangerous.

Travel should be avoided unless absolutely necessary. Fortunately, conditions are expected to improve within a few hours.

By dinnertime, widespread snowfall is likely across most of Central Ontario, portions of Eastern Ontario, and areas east of the Lake Huron shoreline.

The worst conditions are expected early in the event, as the snow begins and winds are strongest, with gradual improvement into the later evening hours.

The greatest risk of blizzard conditions will be across Grey-Bruce, the Georgian Bay shoreline, Muskoka, and Parry Sound, where the heaviest snow and strongest winds are forecasted to overlap.

An intense, narrow band of snow is also expected to develop along the cold front as it moves through Southern Ontario in the evening.

This frontal snow squall could bring a sudden burst of heavy snow almost everywhere in Southern Ontario, lasting less than an hour.

The squall is expected to reach Central and Eastern Ontario by mid to late evening, while the Greater Toronto Area and Niagara region may not experience it until closer to midnight.

This squall is not expected to produce significant snowfall totals, as it will pass through quickly. However, it could bring 2 to 5 cm of snow within 15 to 30 minutes, along with brief but intense blowing snow.

Although conditions may feel like a blizzard during this time, they likely won’t meet the official criteria, which require blizzard conditions to last at least four hours. That criteria is more likely to be met around the Lake Huron and Georgian Bay shoreline as the snow starts earlier in the day.

By the end of Monday, the highest snowfall totals are expected in the higher elevations of Central Ontario, including Huntsville, Sundridge, Algonquin Park, and North Bay, where accumulations of 10 to 20 cm are likely, though closer to the lower end of that range.

For the rest of Central Ontario and areas east of Lake Huron, including Hanover, Orangeville, and Collingwood, this event is expected to bring 5 to 10 cm of fresh snowfall.

Eastern Ontario and the Lake Huron shoreline should see 2 to 5 cm, primarily from the passing snow squall.

The Golden Horseshoe and Deep Southwestern Ontario are likely to receive less than 2 cm of snow.

In Northern Ontario, snow will begin late Sunday night and continue through much of Monday.

The heaviest accumulations will occur east of Lake Superior, where lake enhancement and embedded snow squalls could push totals to 20 to 30 cm in areas like Wawa and Sault Ste. Marie.

Blizzard conditions are possible during the morning and afternoon in these regions, with wind gusts reaching 70 to 90 km/h near the shoreline.

The rest of Northeastern Ontario, stretching from North Bay to Cochrane along the Quebec border, is expected to receive 10 to 20 cm of snow by the end of Monday.

Sudbury, which may find itself in a dry pocket, is forecasted to see 5 to 10 cm, closer to the lower end of that range, while Elliot Lake should receive less than 5 cm.

December 03, 2024

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

December 03, 2024/ Brennen Perry

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

November 18, 2024

‘Blizzard Conditions Possible’; Winter Storm Could Dump Up to 30cm of Snow on Parts of Saskatchewan and Manitoba Early This Week

November 18, 2024/ Brennen Perry

Mother Nature isn’t holding back as a powerful winter storm sets its sights on Saskatchewan and Manitoba, starting late Monday. This storm will bring heavy snow, strong winds, and even blizzard conditions, marking the region’s first significant taste of winter. Some areas in Eastern Saskatchewan and Western Manitoba could see up to 30 cm of snow, with localized amounts possibly exceeding that by the end of Wednesday.

Sustained winds of 40 km/h, with gusts reaching 70–80 km/h, are expected to create blowing snow, particularly overnight Tuesday into Wednesday morning. Blizzard conditions could develop in some areas. Prepare for hazardous travel, as highway closures are likely in the hardest-hit regions.

Before diving into the details, it’s important to note that this is a complex storm, with snowfall accumulating over multiple days. This preliminary forecast provides a general idea of the storm’s potential impacts, but adjustments are likely as the system approaches. Stay tuned for updates, including a more detailed snowfall accumulation map in the coming days.

The storm will begin in Saskatchewan late Monday afternoon or evening, as precipitation moves into the province from the south. The first round of snowfall will primarily impact Central and Northeastern Saskatchewan, with areas like Prince Albert and Nipawin expected to see the heaviest snow through late Monday.

Overnight Monday into early Tuesday, precipitation in Saskatchewan will merge with an approaching system from the south, targeting Manitoba. The exact track of this system remains uncertain, but it’s expected to bring significant precipitation to Manitoba throughout Tuesday.

Initially, much of Eastern Manitoba, including Winnipeg, will see heavy rain. By Tuesday late morning or early afternoon, colder air will begin to wrap into the region, creating a risk of freezing rain in parts of Southwestern Manitoba, including Brandon and Portage la Prairie.

Meanwhile, heavy snow will persist across Eastern Saskatchewan, where Arctic air is firmly in place. There is some uncertainty about how far west the precipitation will extend into Saskatchewan, but the heaviest snow is expected closer to the Manitoba border.

By Tuesday late afternoon, most of Manitoba will transition from rain to snow as colder air overtakes above-freezing temperatures. Heavy snow will continue through the overnight hours into Wednesday morning.

**SUSTAINED WIND SPEED** - MAP FROM WEATHERBELL

Strong winds, with sustained speeds near 40 km/h and gusts of up to 70 km/h, will develop late Tuesday and persist into much of Wednesday. Combined with heavy snowfall, this will likely lead to blowing snow and blizzard-like conditions, particularly in parts of Eastern Saskatchewan and Western Manitoba.

As the system exits the region later on Wednesday, the snowfall will gradually taper off. However, this storm will usher in the coldest air of the season so far, with temperatures dropping to -10°C to -20°C by the end of the week.

Snowfall Accumulation

Monday

By the end of Monday, snowfall totals are expected to reach 5–10 cm in parts of Central and Eastern Saskatchewan, including Prince Albert, Melfort, and Tisdale. Surrounding areas, such as Saskatoon and Wynyard, could see up to 5 cm of snow.

Tuesday and Wednesday

From Tuesday through Wednesday, snowfall totals are expected to range between 15 and 30 cm across much of the affected region. The heaviest accumulations are anticipated near the Saskatchewan–Manitoba border, where localized totals could exceed 30 cm. Elevation will play a significant role, especially in Western Manitoba, where areas of higher terrain could see as much as 30–40 cm.

In Central and Eastern Manitoba, snowfall amounts are harder to pinpoint, as the transition from rain to snow will dictate final totals. Portage la Prairie could see 15–25 cm, while Winnipeg may only receive 10–15 cm, depending on how long the rain lingers before changing to snow.

A similar uncertainty exists in Saskatchewan, but for a different reason—how far west the moisture will penetrate into the province. Some forecasts keep the heaviest precipitation closer to the Manitoba border, while others push it further west. Regina sits on the edge of the higher accumulation zone, with current estimates suggesting 5–15 cm for the city and surrounding areas.

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