July 02, 2026

Another Round of Damaging Storms Could Hit Southern Ontario Thursday With Tornado Risk Increasing

July 02, 2026/ Brennen Perry

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After an active Canada Day that saw storms sweep through Southern Ontario, causing damage and power outages from widespread damaging wind gusts, Thursday may feel like déjà vu for some areas. For parts of the province, this could be the third severe weather risk of the week.

Fueling all of this active weather is the ongoing heat event, which has led to temperatures soaring into the mid to upper 30s across many locations. Thursday is expected to be similarly hot, creating more than enough instability for another round of severe weather.

While Wednesday’s risk was mainly focused on damaging wind gusts, Thursday could feature a more defined tornado risk, with one or two tornadoes possible. The focus of this tornado risk appears to be in Southwestern Ontario near the Lake Huron shoreline, along with parts of Eastern Ontario, including the Ottawa Valley.

The damaging wind gust threat also remains very present. Similar linear-like storms could sweep through a corridor from Lake Huron into the GTA, and then toward the Lake Simcoe, Peterborough and Kingston areas.

Up to Timbit-sized hail is also possible, especially across Eastern Ontario, along the Lake Huron shoreline and around the London area. In these regions, a more isolated storm mode could support a few supercell thunderstorms.

Once again, models are struggling to pinpoint exactly when and where storm development will happen. They tend to perform poorly in these types of dynamic setups, especially when storms are triggered by smaller-scale features such as lake breezes and outflow boundaries from other storms.

What we do know is where the strongest environment is located, along with a rough idea of where models are most likely to develop storms.

That begins during the afternoon, when we could see isolated cells develop from the Lake Simcoe area down toward Kingston. These storms could support a tornado risk, which is why this corridor is also highlighted on our map for tornado potential.

However, confidence is lower in this area. Not every model shows storm development, so this part of the forecast will depend heavily on whether the right triggers are in place.

Another zone of possible storm development can be found across the Ottawa Valley and Eastern Ontario during the evening. A strong shear environment could support rotation if storms are able to develop.

Similar to the afternoon Lake Simcoe risk, confidence is lower here because not all models show storm development. The threat will depend on whether storms can actually form and take advantage of the environment.

The Lake Huron storms may eventually merge into a larger complex and bring a potential late-night damaging wind gust risk through the GTA and Niagara region.

There is still some question about how long this complex would be able to maintain its strength, especially once we lose daytime heating. However, if it holds together, damaging wind gusts could once again become a concern.

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Overall, the forecast for Thursday looks quite similar to Wednesday. We have a “Strong” (Level 3/5) severe risk across a large area, but this time it also includes portions of Deep Southwestern Ontario, including the Sarnia and London areas, along with the Golden Horseshoe.

Other locations included in this risk zone are Goderich, Owen Sound, Kitchener, Hamilton, Guelph, Toronto, Newmarket, Barrie, Orillia, Peterborough, Belleville and Kingston.

This risk is being driven by the potential for strong wind gusts within this corridor, with multiple linear storms possible. If these storms can organize, they could lead to widespread wind damage. There is also the risk for up to Timbit-sized hail and one or two tornadoes.

We have a “Widespread” (Level 2/5) severe risk for Windsor, Chatham and the Lake Erie shoreline, extending into the Niagara region. There is also another “Widespread “ risk zone through Muskoka, Algonquin Park, Bancroft and the Ottawa Valley.

These areas are outside the zone most likely to see the most widespread damaging wind gusts, so the primary threat here will be driven by up to Timbit-sized hail and the risk for one or two tornadoes.

Another major concern is flooding, especially in the Ottawa Valley. This region saw significant flooding on Wednesday after more than 100 mm of rain fell in some areas. Flooding could once again become a serious issue if storms linger over the same communities or repeatedly track over the Ottawa area.

For northern sections of Central Ontario into Northeastern Ontario, including North Bay, Sudbury and Elliot Lake, we have an “Isolated” (Level 1/5) severe risk. We are not expecting widespread severe weather in this area, but with so much energy in the atmosphere, we cannot rule out an isolated pop-up storm capable of becoming severe.

July 01, 2026

Strong Severe Storm Risk Threatens Canada Day Across Southern Ontario, Damaging Winds and Isolated Tornadoes Possible

July 01, 2026/ Brennen Perry

Hot and humid weather has arrived across Southern Ontario just in time for Canada Day, with temperatures soaring into the mid-to-upper 30s, with the humidex making it feel into the 40s. While many will be heading outside to celebrate, this intense heat is also creating an atmosphere that is primed for severe thunderstorms later today.

Unfortunately, this stormy weather could put a damper on Canada Day celebrations, particularly across portions of Southwestern, Central and Eastern Ontario.

We are tracking a conditional severe weather threat for Wednesday afternoon and evening, with the risk potentially continuing into the overnight hours. The hot, humid air will provide plenty of fuel for thunderstorm development. Wherever storms are able to form, they could rapidly become severe thanks to the extremely unstable atmosphere.

In addition to isolated storm development, there is also the potential for one or more organized linear complexes of thunderstorms to move through Southern Ontario. If these systems develop and hold together, they could produce widespread damaging wind gusts across a large portion of the province.

We continue to describe today's threat as conditional because forecast models are doing a poor job of determining exactly where storms will develop. We know the environment is more than capable of supporting severe thunderstorms, but storms first need to form in order to take advantage of the available instability.

Development may be triggered by lake breeze boundaries, leftover outflow boundaries from earlier storms, or other small-scale features that are notoriously difficult to predict ahead of time. As a result, not everyone will see a thunderstorm today, but those that do could experience very intense conditions.

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As of 1 PM, we're already watching a strong complex of thunderstorms developing over Northern Michigan that is tracking toward Lake Huron and eventually Southwestern Ontario by the mid to late afternoon. If this complex is able to maintain its strength as it crosses into Ontario, it could produce widespread damaging wind gusts from areas east of Lake Huron through the Lake Simcoe region and eventually into Eastern Ontario.

Additional thunderstorms may also develop later today across Quebec before sweeping into portions of Eastern Ontario and the Ottawa Valley during the evening and early overnight hours.

Outside of these organized storm complexes, isolated thunderstorms may develop almost anywhere across Southern Ontario this afternoon and evening. If they are able to establish themselves before merging into larger clusters, a few discrete supercells could develop.

These storms would be capable of producing damaging wind gusts, hail up to the size of Timbits and an isolated tornado. While the tornado threat appears highest across Eastern Ontario, an isolated tornado cannot be ruled out anywhere in Southern Ontario today.

We have a 'Strong' (Level 3/5) severe weather risk for locations including Goderich, Kincardine, Owen Sound, Hanover, Collingwood, Midland, Barrie, Orillia, Bracebridge, Peterborough, Tweed, Bancroft, Smiths Falls, Renfrew, Ottawa, Brockville and Cornwall. This higher risk is primarily driven by the potential for widespread damaging wind gusts this afternoon and evening, although large hail and an isolated tornado are also possible.

Surrounding areas, including Grand Bend, Woodstock, Kitchener, Guelph, Hamilton, Toronto, Newmarket, Oshawa and Kingston, are under a 'Widespread' (Level 2/5) severe weather risk. These locations could also experience damaging wind gusts if storm complexes hold together, although the tornado risk is somewhat lower compared to Central and Eastern Ontario.

We also have an 'Isolated' (Level 1/5) severe weather risk across the rest of Deep Southwestern Ontario, along with the Niagara region. While storm coverage is expected to remain limited here, any storm that does develop could quickly become severe given the highly unstable environment.

Farther north, we have gone with an 'Widespread' (Level 2/5) to 'Isolated' (Level 1/5) severe weather risk across northern portions of Central Ontario, including North Bay and Sudbury. Storms that develop in this region could strengthen before tracking south and eastward into Quebec and Eastern Ontario.

The severe weather threat should gradually diminish around midnight. However, thunderstorms may continue overnight as the atmosphere will remain exceptionally unstable despite the loss of daytime heating. If a mature storm complex is able to move through overnight, isolated severe weather will remain possible, with damaging wind gusts posing the primary threat.

June 29, 2026

Multiple Tornadoes and Tennis Ball Sized Hail Possible Monday Across Manitoba and Northwestern Ontario

June 29, 2026/ Brennen Perry

After a destructive severe weather outbreak that brought violent tornadoes to Western Manitoba on Sunday, the risk shifts eastward into Winnipeg, Eastern Manitoba and Northwestern Ontario on Monday.

Based on the latest forecast data, today's storms could bring a similarly dangerous setup with the potential for significant severe weather, including multiple tornadoes, huge hail up to the size of tennis balls, destructive wind gusts in excess of 100 km/h, and areas of flash flooding.

The greatest concern is across areas just southeast of Winnipeg where we have issued a 'significant' severe weather risk. This includes Winkler, Steinbach, Kenora, Dryden, Atikokan and Fort Frances.

Storms that develop in this corridor will have the potential to rapidly become powerful supercells capable of producing all severe weather hazards. The tornado threat is expected to be highest in this zone where atmospheric conditions appear most favourable for rotating thunderstorms.

A 'strong' severe weather risk extends across the rest of South-central and Eastern Manitoba, including Winnipeg, Portage la Prairie, Carman, Killarney, Selkirk, Gimli, Ashern, Arborg, Peguis, Pine Falls, Red Lake, Sioux Lookout and Thunder Bay.

While damaging wind gusts and large hail will likely be the primary hazards across much of this area, an isolated tornado cannot be ruled out, especially across South-central Manitoba and the Interlake region where conditions may still support discrete rotating storms before they begin to organize into larger clusters.

Farther west, there is a widespread to isolated severe weather risk across Western Manitoba, including Brandon, Virden, Dauphin, Roblin and Swan River. Flooding is expected to be the biggest concern in this region as slow-moving thunderstorms could repeatedly track over the same communities.

Rainfall totals could exceed 100 mm in localized areas, leading to flash flooding. An isolated tornado also cannot be ruled out around the Brandon area during the afternoon should any storms remain isolated long enough to become organized.

**SIMULATED RADAR** - MAP FROM WEATHERBELL

Today's severe weather threat is expected to begin during the afternoon with slow-moving thunderstorms developing across Western Manitoba, particularly near the Brandon area.

These storms will move very little, increasing the risk of training thunderstorms where multiple storms repeatedly pass over the same locations.

This could quickly lead to localized flooding, but these storms may also be capable of producing large hail, damaging wind gusts and even an isolated tornado.

The primary severe weather outbreak is expected to unfold later in the afternoon and into the early evening as isolated thunderstorms develop along the international border from Winkler eastward through Southeastern Manitoba and into Fort Frances in Northwestern Ontario.

The atmosphere during this period is expected to be highly supportive of supercell development. Any storm that can remain isolated will have the potential to produce tornadoes, very large hail and destructive wind gusts.

Hail could reach the size of tennis balls in the strongest storms, which would be capable of causing significant damage to vehicles, roofs and crops.

Winnipeg sits near the northwestern edge of the greatest severe weather threat. While current guidance keeps the most dangerous storms just southeast of the city, even a small shift farther west could bring a much higher tornado risk into the Winnipeg area.

The tornado threat should gradually decrease after sunset as daytime heating fades and the atmosphere becomes less favourable for discrete supercells. However, that will not mark the end of the severe weather threat.

As the evening progresses, many of the isolated storms are expected to merge into one or more organized lines of thunderstorms. While the tornado risk will lessen, these storm lines could produce widespread destructive wind gusts capable of causing tree damage, power outages and structural damage across parts of Manitoba and Northwestern Ontario.

These storms could reach the Winnipeg and Thunder Bay regions around midnight with another round of severe weather. Although the primary concern overnight will shift toward damaging straight-line winds, an isolated nocturnal tornado cannot be completely ruled out.

The severe weather threat should come to an end across Manitoba after midnight as the storm complex moves eastward. However, portions of Northwestern Ontario may continue to see strong to severe thunderstorms into Tuesday morning before the system gradually weakens and exits the region.

June 27, 2026

Canada Day Heatwave Set to Grip Southern Ontario With Near 40°C Heat and Severe Storm Risk

June 27, 2026/ Brennen Perry

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As we approach the end of June, the weather is set to heat up in a big way across Southern Ontario with the arrival of a prolonged heatwave that is expected to bring dangerously hot temperatures by Canada Day. Based on the latest forecast data, there appears to be very little relief from the heat in the short term, with above seasonal temperatures potentially lasting through much of the week before easing closer to normal by next weekend.

The heat begins to build on Monday and Tuesday with daytime highs approaching the 30°C mark for the first time during this event. Ironically, these may end up being the “coolest” days of the week as temperatures continue to climb, with some areas potentially reaching the mid 30s by Canada Day, even before humidity is taken into account.

To make matters worse, there will be very little relief overnight. Starting Tuesday night, temperatures are expected to remain in the low to mid 20s across much of Southern Ontario. These unusually warm nights prevent homes and buildings from cooling down and give people little opportunity to recover from the daytime heat, increasing the risk of heat-related illnesses, especially after several consecutive days of extreme temperatures.

In addition to the heat, this warming trend is also expected to create an increasingly unstable atmosphere that will provide plenty of fuel for thunderstorms throughout the week. That doesn't necessarily mean storms will develop every day. Thunderstorms also require a trigger to get started, even when the atmosphere is primed.

However, the ingredients are expected to be in place for multiple rounds of thunderstorms over the coming week, including the potential for severe weather beginning as early as Tuesday.

**ESTIMATED TEMPERATURE (°C)** - MAP FROM WEATHERBELL

This heat event officially begins on Monday with daytime temperatures generally ranging from 27 to 30°C across Southern Ontario.

Keep in mind that communities located along the shorelines of the Great Lakes may remain a few degrees cooler where lake breezes develop. These breezes act like a natural air conditioner by pulling cooler air off the water and pushing it inland, offering some temporary relief for locations directly downwind.

Tuesday brings another step upward with daytime highs expected to exceed 30°C across nearly all of Southern Ontario.

The hottest temperatures are expected across Southwestern Ontario, along with the Golden Horseshoe, where the urban environment creates what is known as the ‘urban heat island’ effect. Cities contain large amounts of concrete, asphalt and buildings that absorb heat from the sun throughout the day. Unlike forests or grassy areas, these surfaces release that stored heat slowly overnight, causing cities to remain noticeably warmer than surrounding rural areas, especially during prolonged heat events.

Temperatures in these areas are currently forecast to reach between 33 and 36°C. Once humidity is factored in, it could feel more like the upper 30s or even low 40s.

**ESTIMATED CAPE** - MAP FROM WEATHERBELL

Along with the increasing temperatures on Tuesday will come a significant surge in thunderstorm energy. Forecast models are showing CAPE (Convective Available Potential Energy) values ranging from 2,000 to more than 4,000 J/kg across much of Southern Ontario. For perspective, CAPE values between 1,000 and 2,000 J/kg are already considered more than sufficient to support strong to severe thunderstorms.

While CAPE is only one ingredient needed for severe weather, it gives us an indication of how much energy is available for developing thunderstorms. The higher the CAPE, the greater the potential for storms to grow rapidly and become intense if they are able to form.

What CAPE cannot do on its own is actually produce thunderstorms. A triggering mechanism is still needed to force warm, humid air upward. Common triggers include an approaching cold front, a warm front, lake breeze boundaries, outflow boundaries from earlier storms or even the heating of the ground during the afternoon. Without one of these lifting mechanisms, the atmosphere can remain loaded with energy while little or no storm development occurs.

Since this energy is expected to remain in place for much of the week, there is a high likelihood that at least a few rounds of thunderstorms will develop. Some of these storms could certainly become severe. At this point, Wednesday and Thursday appear to offer the greatest chance for thunderstorm development, although we're still several days away and the exact timing, location and severity will become clearer as we get closer. This will need to be closely watched as it could put a damper on Canada Day celebrations.

While temperatures will cool somewhat overnight, the overnight relief will be minimal, particularly across Southwestern Ontario and the Greater Toronto Area.

Current projections suggest temperatures on Wednesday morning may struggle to fall below 25°C in these areas before sunrise, with most other parts of Southern Ontario remaining above 20°C.

These warm overnight temperatures are particularly concerning because they greatly increase the health risks associated with prolonged heat. Normally, cooler nights allow the body to recover from daytime heat stress and help homes naturally cool down.

When temperatures stay elevated all night, that recovery becomes much more difficult, especially for seniors, young children, those with chronic health conditions and anyone without access to air conditioning, such as the unhoused. Several consecutive nights of poor overnight cooling can significantly increase the risk of heat exhaustion and heat stroke.

Extreme heat can affect anyone, not just vulnerable groups, so it's important to take precautions throughout this event.

Stay well hydrated by drinking plenty of water, even if you don't feel thirsty, and try to avoid alcohol or excessive caffeine, which can contribute to dehydration.

Limit strenuous outdoor activities during the hottest part of the day, typically from late morning through the early evening, and wear lightweight, loose-fitting, light-coloured clothing whenever possible.

If you have access to air conditioning, spend time indoors where it's cool. If not, consider visiting a shopping mall, library or community cooling centre for a few hours. Also remember to check in on family members, friends and neighbours, especially older adults, young children and those with underlying health conditions.

Never leave children or pets inside a parked vehicle, even for a few minutes. Temperatures inside a vehicle can climb to dangerous levels extremely quickly!

Finally, learn to recognize the warning signs of heat-related illness. Symptoms such as dizziness, nausea, headache, heavy sweating or confusion should never be ignored. Heat stroke is a medical emergency and requires immediate medical attention!

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As we head into Canada Day, it is shaping up to be an exceptionally hot day with temperatures potentially reaching between 36 and 38°C across Deep Southwestern Ontario and portions of the Greater Toronto Area.

Once again, temperatures could be noticeably cooler near the Great Lakes, where lake breezes develop. With southwesterly winds currently expected, the greatest cooling influence will likely be found along the northeastern shorelines of the lakes.

Elsewhere across Southern Ontario, temperatures are expected to range from 33 to 36°C across much of Southwestern Ontario, around Lake Simcoe and into Eastern Ontario. Central Ontario, along with the higher elevations of the Dundalk Highlands, should remain slightly cooler with highs between 30 and 33°C.

**ESTIMATED FEELS LIKE (°C)** - MAP FROM WEATHERBELL

Humidity is also expected to continue increasing through Wednesday and Thursday, making it feel even hotter. Factoring in the humidex, it could feel well into the low to mid-40s across much of Southern Ontario. The highest humidex values are expected across Deep Southwestern Ontario and the Golden Horseshoe, although Eastern Ontario could also see "feels like" temperatures approaching 40°C.

A similar setup is expected on Thursday with many areas once again climbing into the mid-30s. Temperatures may ease slightly on Friday before a more noticeable cooldown arrives next weekend, bringing conditions back closer to seasonal values.

While the exact timing of that relief may still shift over the coming days, confidence is increasing that Southern Ontario is about to experience its most significant and prolonged heat event of the year so far. Residents should be prepared for several consecutive days of dangerous heat and stay up to date with the latest forecasts as the week progresses.

June 27, 2026

Tornado Risk for Regina Area as Significant Severe Storm Risk Target Saskatchewan & Manitoba Saturday

June 27, 2026/ Brennen Perry

After a brief reprieve from active weather across Saskatchewan and Western Manitoba, the threat of severe thunderstorms returns on Saturday. This round of storms could bring a potentially significant severe weather risk to portions of Southeastern Saskatchewan, especially around Weyburn and Estevan.

Isolated thunderstorms are expected to develop near the International Border around the dinner hour. Any storms that form could quickly become supercells capable of producing all severe weather hazards, including tornadoes, golf ball-sized hail and destructive wind gusts up to 120 km/h.

There is also a strong severe weather risk extending northward toward Assiniboia, Moose Jaw and Regina. An isolated tornado cannot be ruled out in these areas as well, although confidence in storm development is lower compared to locations closer to the border.

Further south, additional thunderstorms are expected to develop across Montana and North Dakota. As the evening progresses, these storms are forecast to merge into a large complex that will race northeast toward Saskatchewan and Southwestern Manitoba.

The earlier isolated supercells over Southeastern Saskatchewan are expected to be absorbed into this larger storm complex as it crosses the border. As this happens, the primary threat will shift from large hail and tornadoes to widespread damaging wind gusts as the storms organize into a fast-moving line during the mid and late evening hours.

This line is expected to sweep northeast from Regina toward the Manitoba border. There is still some uncertainty regarding how well it will maintain its strength after sunset, as the loss of daytime heating will reduce available instability. However, we expect at least an isolated to widespread severe weather risk to continue past midnight as the storms approach the Yorkton and Brandon corridor.

Based on the latest data, isolated thunderstorms are most likely to develop between 5 and 7 PM CST near the International Border. These storms could impact the Weyburn and Estevan areas as they rapidly intensify into supercells capable of producing large hail, damaging wind gusts and tornadoes.

The environment will be particularly favourable for tornadic development during the first few hours of these storms' lifespan. The greatest tornado risk appears to be closest to the border, although this threat could extend northwest toward Moose Jaw and Regina if storms are able to develop there during the late afternoon and early evening.

As the mature line of storms over Montana and North Dakota advances into Saskatchewan, the earlier isolated storms are expected to merge into the line, forming a bowing segment stretching from Regina to the Manitoba border.

Although the tornado threat will decrease once the storms become linear, a brief QLCS spin-up tornado cannot be ruled out, particularly near any bookend vortices that develop within the line. The primary hazard, however, will become widespread damaging wind gusts, with localized gusts over 100 km/h possible. The hail threat will also diminish by this stage, although quarter to toonie-sized hail may still accompany the strongest storms.

The line will continue sweeping across Southeastern Saskatchewan and into Southwestern Manitoba during the overnight hours. While isolated damaging wind gusts will remain possible within the strongest portions of the line, there is still uncertainty regarding how well the storms will maintain their intensity after midnight.

June 25, 2026

Southern Ontario Faces Severe Storm and Tornado Risk Thursday Ahead of Possible Canada Day Heatwave

June 25, 2026/ Brennen Perry

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While the latter half of June has been relatively quiet across Southern Ontario when it comes to severe weather, thanks to cooler temperatures dominating the region, that pattern is about to change in a big way. As we head into the final days of June, much warmer and increasingly humid air will begin pushing into the province, bringing with it a rapidly increasing risk for thunderstorms.

The first significant opportunity arrives on Thursday, when portions of Southwestern Ontario could see a widespread severe thunderstorm risk. An isolated severe threat may also extend farther east into parts of the Golden Horseshoe and Central Ontario.

If thunderstorms are able to develop during the afternoon and early evening, they will move into a very favourable environment capable of supporting supercell thunderstorms. These storms could produce all modes of severe weather, including toonie-sized hail or larger, damaging wind gusts in excess of 100 km/h, torrential rainfall and even a few isolated tornadoes.

The most favourable environment currently appears to be across areas including Sarnia, Chatham, Grand Bend, Goderich and London. However, isolated thunderstorms could also develop as far north as the Bruce Peninsula, east toward Lake Simcoe, and south into portions of the Greater Toronto Area. While the tornado threat decreases farther away from Lake Huron, it cannot be completely ruled out as far east as Kitchener, Hamilton and portions of the southern Georgian Bay shoreline.

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Thursday's forecast does come with one important complication. Morning showers and non-severe thunderstorms are expected to move through Southwestern Ontario before spreading into Central and Eastern Ontario during the day.

As we've seen many times before, morning convection can make or break an afternoon severe weather event. If clouds and showers linger too long, they can prevent the atmosphere from recovering enough to support stronger storms later in the day.

On the other hand, if skies clear by around the noon hour, as many of the latest models suggest, there should be several hours available for temperatures and instability to quickly rebound.

**Significant Tornado Parameter** - MAP FROM WEATHERBELL

By the mid-afternoon, the atmosphere is expected to become increasingly supportive of severe thunderstorms, with the highest risk developing between roughly 2 PM and 6 PM. The strongest combination of instability and wind shear currently appears to be centred near the Lake Huron shoreline, extending into Sarnia and Chatham.

The latest Significant Tornado Parameter (STP) data also highlights an enhanced corridor stretching from the Michigan border across Lake Huron into Southwestern Ontario. Should storms form within this corridor, they could rapidly intensify into rotating supercells capable of producing very large hail, damaging winds and isolated tornadoes.

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There remains some disagreement among the forecast models regarding exactly where storms will first develop.

Some models initiates storms as early as 3 PM across Michigan before they quickly cross into Deep Southwestern Ontario. This scenario would place communities such as Sarnia, Grand Bend, Goderich and London at the greatest risk.

Other models delay development until later in the afternoon or early evening, with storms forming closer to the Hanover to Grand Bend corridor before tracking southeast toward London, Kitchener and possibly Hamilton. Regardless of which solution verifies, the greatest tornado potential continues to favour areas along and just inland from the southeastern Lake Huron shoreline.

Additional isolated thunderstorms may also develop around Lake Simcoe and into the Greater Toronto Area during the late afternoon and early evening. While the environment in these areas appears less favourable for widespread severe weather, a few stronger storms cannot be ruled out. The primary threats would be hail up to quarter size along with isolated damaging wind gusts.

As the sun sets Thursday evening, the severe weather threat should gradually diminish as daytime heating is lost. However, scattered non-severe showers and thunderstorms may continue well into the overnight hours, particularly across Central and Eastern Ontario.

Looking beyond Thursday, the severe weather threat briefly settles down. Friday may bring a very isolated thunderstorm risk across Eastern Ontario, particularly near the Ottawa Valley, while much of the weekend currently appears relatively quiet from a severe weather perspective.

The bigger story heading into next week will likely be the return of significant heat.

Temperatures are expected to steadily climb through the weekend, with many areas approaching or exceeding 30°C by Monday. Current medium-range guidance suggests the heat could continue to intensify into the middle of next week, potentially peaking around Canada Day.

Some forecast models are indicating temperatures running between 5 and 10°C above seasonal averages, with localized anomalies approaching 15°C in parts of Ontario on Canada Day. If those projections verify, daytime highs could reach the low to mid 30s across portions of both Southern and Northern Ontario.

When combined with increasing humidity, it may feel close to 40°C in many communities.

This surge of heat and humidity will also provide plenty of fuel for additional thunderstorm development. While it is still too early to determine exactly which days will carry the greatest severe weather risk, there are increasing signs that we could be entering a much more active pattern over the next one to two weeks. Exactly when storms develop will depend on the arrival of cold fronts and other triggering mechanisms, something that will become much clearer once higher resolution models come into range.

We'll continue monitoring both Thursday's severe weather potential and the possible prolonged heat event expected next week. Stay tuned for forecast updates throughout the coming days as confidence continues to increase.

June 17, 2026

Powerful June Storm System Could Bring Damaging Winds and Isolated Tornadoes to Southern Ontario Overnight

June 17, 2026/ Brennen Perry

An unusually strong and deepening low pressure system for mid-June is set to track through the Great Lakes region overnight Wednesday and into Thursday. This powerful system will bring the potential for severe weather to a large portion of Southern Ontario, with the greatest threat occurring late tonight and into Thursday morning.

The same system is expected to produce a significant severe weather outbreak across portions of Illinois, Indiana and Michigan this afternoon and evening. In those areas, forecasters are highlighting the risk of violent tornadoes, destructive wind gusts and large hail as a potent combination of instability and wind shear develops ahead of the approaching low pressure system.

As this line of storms pushes eastward into Michigan tonight, it is expected to gradually weaken before reaching Ontario. However, weakening does not necessarily mean the severe threat will disappear.

Even in a decaying state, this line of storms could still bring impactful weather to portions of Southwestern Ontario, especially areas closest to the international border and along the Lake Huron shoreline.

Based on the latest forecast data, the primary threat appears to be damaging wind gusts in excess of 100 km/h. In localized areas, stronger wind gusts could occur if isolated downbursts develop within the line of storms. These stronger pockets of wind have the potential to cause tree damage, power outages and scattered property damage.

While the tornado threat will be considerably lower than what is expected across parts of the United States, it cannot be completely ruled out.

The atmosphere over Deep Southwestern Ontario will remain supportive of some rotation early in the night, particularly while the line of storms is still relatively organized. Any tornado risk would likely be brief and localized in nature, but the strong dynamics associated with this system mean it is something we will be watching closely.

Another factor adding complexity to this forecast is the strength of the low pressure system itself.

In addition to thunderstorm-related winds, very strong winds will be present just above the surface overnight. Normally, a temperature inversion would act as a lid and prevent those stronger winds from mixing down to ground level. Current indications suggest that inversion should remain in place for much of the night.

However, if portions of that stronger wind are able to reach the surface, isolated non-thunderstorm wind gusts in excess of 90 km/h would be possible. This risk appears highest near the shorelines of Lake Huron and Lake Erie where local effects can help enhance wind gusts.

We’ll be closely monitoring this severe weather threat throughout the evening and overnight hours.

If conditions warrant, we’ll be going live on our YouTube channel with real-time storm tracking, radar analysis, warning updates and coverage of any severe weather that develops across Southern Ontario.

Be sure to subscribe to our YouTube channel HERE and turn on notifications so you don’t miss any live coverage. Whether it’s damaging winds, tornado warnings or rapidly changing conditions, we’ll be there to keep you informed every step of the way.

Heavy rainfall will also accompany this system. Many areas will receive beneficial rainfall, but localized torrential downpours could lead to rainfall amounts exceeding 50 mm in a relatively short period of time. If storms repeatedly move over the same area, flash flooding could develop, especially in urban locations and areas with poor drainage.

The highest severe weather risk tonight stretches across Deep Southwestern Ontario and portions of the Lake Huron shoreline. This includes Windsor, Leamington, Chatham, Sarnia, Grand Bend, Goderich and Kincardine.

In these areas, storms could begin arriving as early as 8 to 9 PM and continue through the overnight hours. Damaging wind gusts remain the primary concern, although heavy rain and an isolated tornado cannot be ruled out.

As the line progresses eastward, it is expected to reach the London, Woodstock, Kitchener, Guelph, Orangeville and Hanover areas around or shortly after midnight. There remains some uncertainty regarding exactly how much strength the storms will retain by this point. However, the potential still exists for several pockets of damaging winds to survive farther inland.

The tornado threat should be lower compared to areas farther west, but strong winds and localized flooding will continue to be concerns as the line moves through.

By the time the storms reach Central Ontario and the Golden Horseshoe during the overnight hours, the severe threat should be decreasing further. That said, this remains a powerful weather system and some stronger portions of the line could still produce isolated wind gusts approaching 90 km/h.

As a result, we continue to highlight an isolated severe weather risk for Toronto, Hamilton, Niagara, Newmarket, Barrie, Orillia, Bracebridge, Peterborough and Bancroft.

Attention will then shift to Eastern Ontario during the early morning hours on Thursday. Unlike areas farther west, there are indications that the atmosphere may begin to recover somewhat as the main line approaches. There is also the potential for additional isolated thunderstorms to develop behind or ahead of the main line shortly after sunrise.

This could allow for a secondary severe weather threat across portions of Eastern Ontario, particularly near the international border and into the Ottawa Valley. This broader morning severe weather risk includes Kingston, Brockville, Smiths Falls, Cornwall, Ottawa and Picton.

Should additional storms develop within this environment, all severe weather hazards would be possible including damaging wind gusts, heavy rainfall, hail and even an isolated tornado.

Forecast confidence in the tornado threat remains lower due to the early morning timing and questions surrounding how much instability can develop. However, the environment bears watching closely given the strength of the overall weather system.

The severe weather threat is expected to gradually come to an end from west to east through Thursday morning, with most areas seeing the risk diminish by early afternoon.

Even after thunderstorms exit the region, conditions will remain quite blustery throughout the day. Strong non-thunderstorm wind gusts may continue across much of Southern Ontario as the powerful low pressure system pulls away from the Great Lakes.

May 19, 2026

Tornado Tuesday Could Bring Damaging Storms to Southern Ontario With Strong Severe Threat

May 19, 2026/ Brennen Perry

After an active, severe weather day on Monday that left widespread damage across parts of Central Ontario, especially throughout cottage country, another volatile day is shaping up across Southern Ontario.

In fact, Tuesday’s severe weather risk could end up being even stronger than Monday’s in some areas, particularly across Southwestern Ontario extending northeast toward Lake Simcoe and portions of the Golden Horseshoe.

Isolated thunderstorms are expected to develop during the late afternoon and early evening hours, bringing the potential for all modes of severe weather. This includes damaging wind gusts exceeding 100 km/h, hail up to ping pong ball size and the risk for a few tornadoes.

The primary area of concern stretches from Midland southwest toward Sarnia. Conditions in this corridor may support the development of supercells during the early stages of storm development. Supercells are rotating thunderstorms capable of producing tornadoes, very large hail and destructive wind gusts.

This early stage of the event is when the tornado and hail threat is expected to be at its highest, as storms remain isolated and are able to fully tap into the warm, unstable and highly sheared environment in place across the region.

As these storms track north and east through the evening hours, they are expected to gradually transition into a more linear storm mode. In other words, the isolated storms may begin to merge together into a squall line or broken line of embedded thunderstorms as they approach the Golden Horseshoe during the early evening.

At that point, the primary threat would shift away from tornadoes and large hail and toward widespread damaging wind gusts. However, isolated tornadoes can still occur within these types of storm lines through quick spin-ups along the leading edge, even if that is no longer the dominant concern.

The severe weather threat is expected to diminish fairly quickly after sunset, likely between 9 and 10 PM, as the loss of daytime heating weakens the atmosphere’s ability to sustain intense thunderstorms.

Behind the storms, a cold front is expected to sweep through the province overnight, bringing a sharp end to Southern Ontario’s first heat event of the year. By Wednesday morning, some areas could be waking up to temperatures back down in the single digits.

Based on the latest simulated radar data, isolated thunderstorms are expected to begin developing along a line extending from Midland southward toward Sarnia around 6 PM. However, that timing could still shift, especially since these setups can sometimes initiate earlier than forecast.

If storms are able to develop earlier in the afternoon, they would have access to an even more favourable environment, potentially increasing the severe weather risk.

Regardless of exactly when storms first form, the expectation is that they will remain fairly isolated for the first few hours of their lifespan as they track east of Lake Huron and northeast toward regions surrounding Lake Simcoe.

There is particular concern for the Midland to Kawartha Lakes corridor, where several model runs continue to indicate the potential for a dominant supercell to develop and track through the region.

Given that the strongest atmospheric conditions are expected to overlap in this area, any storm that develops there could become quite intense quickly, with the potential for tornadoes and very large hail.

Additional severe thunderstorms may also develop farther southwest and track through areas including London, Kitchener, Orangeville and Barrie during the dinner hour.

Farther east, a few isolated storms may also develop near Bancroft and the Ottawa Valley. However, the environment in those areas does not currently appear to be quite as favourable for widespread severe weather, so confidence in storm intensity there remains lower.

As the evening progresses and daylight fades, the isolated cells are expected to begin merging together into a more organized line of storms while gradually weakening as they approach the Greater Toronto Area.

These storms could certainly remain severe into the evening hours, but the primary threat would likely transition toward damaging wind gusts, which is common with linear storm events.

That does not mean the tornado threat disappears entirely though. An isolated QLCS tornado cannot be ruled out within the line as it tracks eastward through the evening.

QLCS stands for “quasi-linear convective system,” which is essentially a line of thunderstorms capable of producing brief, fast-forming tornadoes embedded within the line itself. These tornadoes are often difficult to detect and can develop with little warning.

The hail threat, however, is expected to decrease significantly by this stage of the event as storms lose their isolated structure and strong updrafts.

Overall, the severe weather risk should come to a fairly quick end shortly after sunset as the atmosphere stabilizes. While a few overnight thunderstorms may linger behind the main line, they are expected to remain below severe limits.

Looking ahead to the rest of the week, Southern Ontario’s brief taste of summer-like weather is set to come to an abrupt end behind Tuesday night’s cold front.

Temperatures are expected to tumble overnight, with some parts of Southwestern and Central Ontario potentially waking up to single-digit temperatures by Wednesday morning. In fact, there may even be some frost risk later this week across portions of Central Ontario as cooler air settles back into the province.

May 18, 2026

Multi-Day Severe Storm and Tornado Risk Targets Southern Ontario Alongside Summer-Like Heat

May 18, 2026/ Brennen Perry

Southern Ontario is about to get its first real taste of summer weather in 2026, and it’s arriving with a potentially stormy side effect.

Temperatures are expected to soar into the upper 20s and even near 30°C in some areas on both Monday and Tuesday as a surge of warm and humid air spreads across the province. While this early-season heatwave will be relatively brief, it’s expected to create a volatile atmosphere capable of producing two consecutive days of severe thunderstorms across parts of Southern Ontario.

From large hail and damaging wind gusts to the possibility of isolated tornadoes, there’s a lot to track over the next 48 hours. Our team will be providing extensive live coverage throughout both severe weather risks on our YouTube channel, with real-time storm tracking, warning updates, radar analysis and live storm chasing coverage as storms develop. If you’re looking for in-depth storm coverage in Ontario, Instant Weather will be the place to be over the next two days.

The first round of potentially severe weather is expected to develop during the mid to late afternoon hours on Monday as strong storms over Michigan begin to track into the Lake Huron and Manitoulin Island area around 3-6 PM. These storms are likely to merge into a single line with embedded cells as they cross the Bruce Peninsula and into regions around the northern and eastern shoreline of Georgian Bay. Early in their lifespan, they could present all storm hazards, including damaging wind gusts and hail up to the size of toonies.

As these storms move into Central Ontario, including much of Ontario’s cottage country such as Muskoka, North Bay and Algonquin Park, the environment could become capable of supporting a brief spin-up tornado. There is still some uncertainty regarding the tornado risk as some models suggest the storms may arrive later in the evening, after the most favourable tornado environment begins to weaken.

A secondary cluster of storms may also approach regions further south and west, including Deep Southwestern Ontario and along the eastern Lake Huron shoreline during the late afternoon and early evening hours. At this point, damaging wind gusts appear to be the primary threat in these areas, while the hail and tornado risk looks lower, although it can never be completely ruled out.

As these clusters of storms track northeast, they are expected to gradually weaken by the late evening as the daytime heating fuelling them begins to fade away. Due to this, there remains some uncertainty regarding how far east the severe risk will extend, as it will largely depend on how quickly the storms move before losing access to the strongest instability.

We have gone with a slight (level 2 out of 5) severe thunderstorm risk for locations including Windsor, Leamington, Chatham, Sarnia, Grand Bend, Goderich, Kincardine, Hanover, Owen Sound, Wiarton, Tobermory, Collingwood, Midland, Bracebridge, Huntsville, Parry Sound, Britt, Manitoulin Island, Sudbury, North Bay, Algonquin Park and Deep River. This is the area most likely to experience the strongest storms today, but it’s important to remember that not everyone within the risk zone will necessarily see severe weather.

A marginal (level 1 out of 5) severe thunderstorm risk includes London, St. Thomas, Woodstock, Tillsonburg, Brantford, Kitchener, Guelph, Orangeville, Barrie, Orillia, Bancroft, Pembroke and Renfrew. If severe weather develops in these areas, it will most likely be isolated damaging wind gusts associated with weakening storms during the evening hours.

Non-severe thunderstorms are also possible for the Greater Toronto Area and parts of Eastern Ontario. While widespread severe weather is not expected there at this time, any storms that do develop could still produce frequent lightning, heavy downpours and locally gusty winds.

Turning towards Tuesday, the overall severe weather setup may become even more favourable and widespread, but confidence in storm development itself remains lower.

A very warm and unstable atmosphere is expected to build across Southern Ontario throughout the afternoon and evening hours. If storms are able to form, they could rapidly intensify and become severe across Southwestern Ontario, the Golden Horseshoe and areas surrounding Lake Simcoe, along with Central and Eastern Ontario. This setup would support all severe weather hazards, including damaging wind gusts, large hail and isolated tornadoes.

However, forecast models continue to struggle with exactly where storms will initiate and whether they will develop at all. That uncertainty is preventing a more aggressive severe weather outlook at this time.

Current indications suggest isolated thunderstorms may first begin developing around Grey-Bruce during the mid-afternoon hours before slowly tracking southeast toward regions around Lake Simcoe between roughly 2-5 PM. Additional thunderstorm development may also occur farther southwest and along the Lake Erie shoreline later in the day.

Like Monday, these storms will be heavily dependent on daytime heating and atmospheric instability. Once the sun begins to set around 8-9 PM, any storms that have developed are expected to gradually weaken fairly quickly.

At this time, it appears the Ottawa Valley may remain outside the main severe weather risk on Tuesday. However, that could still change in our final outlook as confidence increases regarding storm development and storm coverage. The atmosphere across Eastern Ontario will still be somewhat supportive of marginally severe thunderstorms, but confidence is currently not high enough to formally include those regions within the isolated severe risk area.

May 16, 2026

Victoria Day to Bring Early Tease of Summer to Southern Ontario With 30°C Heat and Severe Storm Risk on Monday

May 16, 2026/ Brennen Perry

After a chilly and wet start to May across Southern Ontario, it finally looks like summer is ready to make an appearance, just in time for the Victoria Day long weekend.

The first half of the month has certainly felt more like an extension of early spring than the lead-up to summer. We’ve dealt with multiple rounds of widespread frost, temperatures consistently running below seasonal, and even reports of wet flurries in some areas.

While we did get a brief taste of severe weather with Canada’s first confirmed tornado of 2026 on May 9th near Lucan (northwest of London), the summer-like warmth has been hard to come by. That’s about to change!

The Victoria Day long weekend, often considered the “unofficial start of summer” in Ontario, is expected to fully live up to the title this year. A significant warm-up is set to spread across Southern Ontario through the weekend, peaking on Monday with widespread summer-like heat and humidity.

The hottest temperatures on Monday are expected to be found in Deep Southwestern Ontario extending into the western GTA and Niagara region, including Windsor, Chatham, Sarnia, London, Grand Bend, Woodstock, Brantford, Hamilton and Niagara Falls. Daytime highs in these areas are likely to range between 30-33°C with humidex values potentially approaching 35°C at times.

While many will be excited to finally enjoy some summer-like weather, it’s important to remember that the first major heat event of the season can be particularly stressful on the body. Be sure to stay hydrated, limit strenuous outdoor activity during the hottest part of the day, and never leave children or pets unattended in vehicles. Pets can also quickly overheat on hot pavement, so it’s a good idea to check surfaces before heading out for a walk.

For much of the rest of Southern Ontario, daytime highs are expected to range between 27-30°C, with the humidity making it feel into the low 30s. This includes Toronto, Kitchener, Barrie, Muskoka, Peterborough, Kingston and Ottawa.

The higher elevations of the Dundalk Highlands are likely to remain a few degrees cooler, with areas like Orangeville and Shelburne expected to top out closer to 24-27°C.

Meanwhile, temperatures directly along portions of the Lake Erie and Lake Ontario shoreline may stay noticeably cooler thanks to developing lake breezes. Southwest winds coming off the still-cool lake waters will help suppress temperatures near the shoreline through the afternoon hours.

As a result, locations such as Picton, Cobourg, Oshawa, Fort Erie, Port Colborne, Port Dover, Turkey Point and Leamington could struggle to climb much beyond the low 20s despite the intense heat further inland.

A similar cooling effect is expected along the Bruce Peninsula, Manitoulin Island and parts of the northern Georgian Bay shoreline. Locations such as Britt, Manitoulin Island and Tobermory are also expected to remain closer to 20°C.

The heat is expected to continue into Tuesday with similar daytime highs before a cold front sweeps through later in the week, returning temperatures closer to seasonal or even slightly below seasonal levels.

Another concern with the return of summer-like heat will be the increasing fire danger across parts of the province. According to the latest forecast from the Canadian Wildland Fire Information System, portions of Deep Southwestern Ontario could see fire danger levels reach high or even extreme on Monday, thanks to the combination of hot temperatures, dry conditions and gusty winds.

With many people planning campfires and fireworks for the Victoria Day long weekend, it’s especially important to use extra caution with any open flames. Be sure to follow all local burning regulations and fire bans, and check with your local municipality before setting off fireworks or lighting a fire. Under high or extreme fire danger conditions, even a small spark can quickly spread and become difficult to control.

With the return of summer-like heat also comes the return of increasing atmospheric instability, which can help fuel thunderstorms. The next few days are expected to feature multiple opportunities for thunderstorms across parts of Southern Ontario.

The first round is expected Sunday night into Monday morning as a batch of non-severe nocturnal thunderstorms potentially tracks through areas near Lake Huron extending into Central and Eastern Ontario.

That activity may help set the stage for another round of storms later Monday afternoon and evening. At this point, the greatest risk for isolated severe thunderstorms appears to be focused east of Georgian Bay around Muskoka, Parry Sound and Algonquin Park. A line of storms may also develop over Michigan and track into Deep Southwestern Ontario later Monday night into Tuesday morning, but the exact intensity remains unclear by the time it reaches the border.

Locations that could potentially see isolated severe storms on Monday include Goderich, Kincardine, Hanover, Owen Sound, Wiarton, Tobermory, Collingwood, Midland, Orillia, Bracebridge, Huntsville, Parry Sound, Britt, North Bay, Sudbury, Algonquin Park, Bancroft, Pembroke and Deep River.

It remains too early to determine the exact storm mode and whether any tornado risk will develop. For now, all severe weather hazards remain possible including damaging wind gusts, large hail and torrential rainfall.

A more detailed severe weather outlook, including specific risk categories and hazard breakdowns, will be issued Sunday night or Monday morning once higher resolution forecast models come into range and confidence improves on the exact storm setup.

We’re also monitoring the potential for a more widespread severe thunderstorm risk on Tuesday as a cold front approaches the region later in the day.

However, there is still some uncertainty regarding the exact timing of the cold front. If it arrives later Tuesday afternoon or evening, there would likely be enough daytime heating available to support stronger storms. If the front arrives overnight or earlier in the day, it could significantly reduce instability and limit the severe weather potential.

At this point, isolated thunderstorms remain possible Tuesday afternoon and evening, but the exact location and intensity of the strongest storms remains uncertain.

April 06, 2026

Up to 5 to 10 cm of Snow and Wind Chills Near -15°C as ‘Third Winter’ Arrives in Southern Ontario This Week

April 06, 2026/ Brennen Perry

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Since the arrival of astronomical spring, the weather has certainly matched the season across Southern Ontario. We’ve seen multiple days of double digit temperatures along with the typical spring thunderstorms. However, as we head into the first full week of April, it appears that our ‘3rd winter’ is on the horizon, bringing with it a blast of cold and snowy weather that many thought was behind us for the season.

The good news is that there is light at the end of the tunnel. This blast of wintry weather will only be temporary, with a return to more seasonal conditions expected towards the end of the week.

It certainly isn’t going without a fight. A heavy burst of snow late Monday and continuing into Tuesday may lead to tricky travel conditions as people head back to school and work after the Easter long weekend. You’ll also need to dust off those winter coats again as temperatures plunge overnight Monday, bringing a brief return to wind chills near -15°C in some parts of Southern Ontario.

While we aren’t expecting widespread significant snowfall accumulation from this late season system, the timing could still leave roads snow covered and slushy ahead of the Tuesday morning commute. The snow will fall within a short timeframe and could be quite heavy at times, leading to reduced visibility and some blowing snow.

Most areas are only expecting to see a few centimetres of snow by the time it tapers off early Tuesday afternoon. However, some pockets, especially across parts of Central and Eastern Ontario, could exceed the 5 cm mark and end up seeing between 5 and 10 cm.

The main caveat is that temperatures will still be near the freezing mark when the bulk of the snow is falling late Monday into early Tuesday morning. This means some of it may melt on contact with the ground before being able to accumulate. As a result, actual totals will vary significantly and could fall short of the 5 to 10 cm mark in some areas if temperatures end up slightly warmer.

An area of heavier snow is expected to track into regions around Lake Huron and into Northeastern Ontario sometime during Monday evening. This could start as a rain and snow mix with temperatures still near freezing, especially near Lake Erie and Deep Southwestern Ontario, but should switch over to snow later in the evening.

Even though we are less than six hours away from the start of the snow, models still disagree on the exact intensity and placement. There also appear to be dry slots within the precipitation, which could lead to some areas getting completely missed. At the same time, some moisture from the lakes may enhance snowfall rates in localized areas.

**Hourly snowfall rates (cm)** - MAP FROM WEATHERBELL

By the pre dawn hours on Tuesday, the snow will become more widespread, extending around the Lake Huron shoreline and into Central and Eastern Ontario.

The heaviest pockets of snow appear likely to track from Muskoka through Peterborough and into the Kingston corridor. This could lead to rapid accumulation if temperatures are cold enough to limit melting. Expect poor driving conditions overnight and early Tuesday morning in this area, with sudden whiteout conditions possible.

Around Lake Huron, we could see a brief return of lake effect streamers affecting the London, Goderich and Kincardine area through the morning hours. This may also include the southern shoreline of Georgian Bay.

Wind gusts approaching 50 to 70 km/h may lead to blowing and drifting snow in these areas. While overall accumulation is expected to be limited, even a small amount of snow in exposed rural areas can make travel difficult when paired with strong wind gusts.

We are expecting all of the snow to taper off by early Tuesday afternoon as the main system moves out of Eastern Ontario. Winds will also begin to lighten, shutting off any lingering lake effect activity from Lake Huron and Georgian Bay.

Even if you don’t see accumulating snow, you will still get a taste of Southern Ontario’s third winter over the next few days in the form of bitterly cold temperatures.

It will pale in comparison to the cold we dealt with earlier this year, but it may feel more brutal after many areas hit 20°C just a few days ago. Now, we’re looking at temperatures between -5°C and -10°C to start the day on Tuesday. Factoring in the wind chill, many areas will feel into the negative double digits, with parts of Central and Northeastern Ontario ranging from -15°C to -20°C Tuesday morning.

Thankfully, temperatures are expected to quickly improve by Wednesday and Thursday. Daytime highs will inch back above the freezing mark and could even reach double digits by the end of the week in some areas.

As mentioned, this event will feature significant variation in snowfall totals across the region, making it difficult to pinpoint exact amounts. This is due to both the scattered nature of the snow and temperatures hovering near freezing, along with ground warmth from the recent mild weather. That means not everyone will see accumulating snow, even within the highest forecast zone.

The zone of highest accumulation is expected to include much of Central Ontario extending into Eastern Ontario south of the Ottawa Valley. This includes Kingston, Belleville, Peterborough, Bancroft, Orillia, Bracebridge, Huntsville, Algonquin Park, Parry Sound, Sudbury and Elliot Lake. These areas could see general totals of 5 to 10 cm, with localized pockets potentially exceeding that up to 15 cm. Not everyone within this zone is guaranteed to see 5 cm, as local temperatures will determine how much of the snow is able to stick.

A few centimetres of snow are expected around the Lake Huron and Southern Georgian Bay shoreline, including Grand Bend, Goderich, Kincardine, Owen Sound, Hanover, Collingwood and Barrie. Around 2 to 5 cm is possible here, but due to the nature of lake effect snow, some localized areas could see up to 8 cm, while others may get completely missed.

A trace to a light dusting of snow is expected for Deep Southwestern Ontario into the Golden Horseshoe, along with the Ottawa Valley. Much of this is unlikely to stick to the ground.

No matter how much snow you receive, it will almost certainly be gone within 24 hours thanks to temperatures rising above freezing by Wednesday. That means you likely won’t need to bring those shovels back out of storage.

March 19, 2026

Winter Crashes the First Day of Spring, Snow and Ice to Disrupt Friday Commute in Southern Ontario

March 19, 2026/ Brennen Perry

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With the official start of astronomical spring arriving on Friday, Southern Ontario is set to enter a weather roller coaster. It begins with a heavy burst of messy, mixed precipitation that could impact the Friday morning commute. At the same time, parts of Southwestern Ontario will welcome the first day of spring with double-digit temperatures, with some areas potentially flirting with the 20°C mark.

As temperatures begin to rise on Friday, a fast moving system will push across Southern Ontario ahead of the warmer air. With surface temperatures still below freezing early in the day, some of the precipitation will fall as snow, ice pellets, and even freezing rain.

While the heaviest precipitation will only last for a few hours, the timing could not be worse. It is expected to peak across Southwestern Ontario and the Golden Horseshoe during the mid to late morning hours. This will likely create slippery road conditions right in the middle of the morning commute.

There is still some uncertainty when it comes to exact precipitation types, as temperatures will gradually rise through the day. In many areas, it will likely begin as snow, then transition to ice pellets, followed by a period of freezing rain, before eventually changing over to regular rain. South of Lake Simcoe, the main transition will be from ice pellets to freezing rain.

In higher elevations such as the Dundalk Highlands and the Oak Ridges Moraine, slightly cooler temperatures may allow freezing rain to last longer and become more impactful, with greater potential for ice accretion.

Across Central and Eastern Ontario, heavy snow from the late morning into the early afternoon is expected to lead to quick accumulation. Many areas could pick up around 10 cm, give or take 5 cm depending on how much mixing occurs, especially closer to Lake Simcoe and Lake Ontario. This snow is likely to fall rapidly within a 2 to 3 hour window, with snowfall rates exceeding 5 cm per hour at times. Expect brief whiteout conditions and fast accumulation while it is falling.

Precipitation is expected to move into Southwestern Ontario around sunrise, then gradually spread eastward into the Golden Horseshoe and Central Ontario by the late morning, roughly between 8 and 10 am. As it arrives, it will encounter a layer of cold air near the surface that will be slow to move out. This will help set up a swath of winter weather, with snow stretching from Muskoka into Eastern Ontario, and a mix of ice pellets and freezing rain developing around Lake Simcoe and into Peterborough.

More persistent freezing rain is likely across higher elevations northwest and north of the Greater Toronto Area. For areas closer to Lake Ontario and outside of the higher terrain, freezing rain will be more limited, generally lasting an hour or two during the mid to late morning before temperatures rise.

**HOURLY SNOWFALL RATE (CM)** - MAP FROM WEATHERBELL

The snow band moving through Muskoka, Peterborough, and into Eastern Ontario could be quite intense at times. Snowfall rates may briefly reach 3 to 6 cm per hour late in the morning into the early afternoon. Some of this precipitation may fall as ice pellets, which could reduce overall snow totals slightly.

As temperatures continue to rise, areas around the Greater Toronto Area should transition to regular rain by around midday. However, a corridor of freezing rain may develop from Barrie through Peterborough and into Kingston. This, combined with slushy snow, could result in very poor road conditions with icy patches.

Precipitation will gradually taper off through the afternoon, with Eastern Ontario likely being the last region to see it come to an end.

Temperatures will vary significantly across the region on Friday afternoon. Deep Southwestern Ontario, including Windsor, Leamington, and Chatham, could surge well into the double digits and approach 20°C. Meanwhile, Central and Eastern Ontario may struggle to climb above the freezing mark.

The good news is that most areas expecting any notable ice accretion should see temperatures rise above freezing by the afternoon. This will help reduce the overall impact on tree branches and power lines, and also improve road conditions as the day goes on.

Overall impacts will vary quite a bit depending on location. Across Central and Eastern Ontario, the main story will be heavy snow. Accumulations are expected to range from 5 to 10 cm, with some areas potentially approaching 15 cm. This includes regions north of a line from Gravenhurst to Brockville, including Muskoka, Haliburton, Bancroft, Pembroke, Renfrew, Smiths Falls, Ottawa, and Cornwall.

South of this line, a narrow corridor from Simcoe County through Kawartha Lakes, Peterborough, and into Kingston will likely see a mix of everything. This includes a period of snow, followed by ice pellets, and finishing with some freezing rain. Total accumulation in this zone will range from 2 to 10 cm, with higher amounts toward the northern edge.

The most persistent freezing rain is expected across higher elevations, including areas such as Flesherton, Shelburne, Arthur, Fergus, Guelph, Orangeville, Vaughan, and Newmarket. These areas could see between 2 and 6 mm of ice accretion.

Closer to Lake Simcoe, including northern York Region into Durham Region, around 2 to 4 mm of icing is possible, along with some ice pellets.

Near the Lake Ontario shoreline, including the Greater Toronto Area into Hamilton, Kitchener, Perth, and Grey Bruce, freezing rain is expected to be brief. Most areas will see less than 2 mm of ice, and impacts should be limited as temperatures rise above freezing relatively quickly.

For areas along the Lake Huron and Lake Erie shorelines into Deep Southwestern Ontario, this system will stay primarily on the rain side, with little to no winter precipitation expected.

March 16, 2026

Winter Roars Back Across Southern Ontario Tuesday With Up to 30 cm of Snow and -20°C Wind Chills

March 16, 2026/ Brennen Perry

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It sure may have felt like winter was behind us for the first half of March, but the second half of the month will serve as a snowy and chilly reminder of what Mother Nature is still capable of across Ontario.

We certainly saw that over the past 24 hours in Northern Ontario, where some communities were buried under more than 50 cm of snow from a late-season winter storm. And over the next 24 hours, Southern Ontario will join them in sharing some of that snowy misery.

The system that brought the heavy snow to Northern Ontario has now begun to move out over Quebec. As it exits the region, it is set to usher in a blast of cold air late Monday evening into the overnight hours. That includes the return of a familiar word, snow squalls.

Moisture from a separate system tracking along the northeastern United States is expected to push into Eastern Ontario and areas around Lake Ontario starting Monday evening. With temperatures dropping quickly behind the departing system, that precipitation is likely to fall in the form of heavy snow.

That snow could become quite intense at times across Central and Eastern Ontario, with snowfall rates of 3 to 5 cm per hour in the heaviest pockets. While it should taper off by the early morning hours on Tuesday, just a few hours of that intensity could be enough to bring 10 to 20 cm by Tuesday morning in some communities.

Further west, plunging temperatures will combine with the now partially ice-free waters of Lake Huron and Georgian Bay to bring a brief resurgence of snow squall activity. While it will not last all day, these squalls could bring locally up to 20 to 30 cm of snow before they wrap up by late Tuesday afternoon. Wind gusts peaking Tuesday morning up to 50 to 70 km/h are likely to combine with the snow squall activity to produce blowing snow and potentially disruptive travel in the snowbelt areas.

Aside from the snow, Tuesday will start off on a very chilly note with wind chills dropping below -20°C in some areas during the morning hours.

Precipitation has already begun to spread into Eastern Ontario as of early Monday evening and is expected to continue increasing in intensity over the next several hours. The worst conditions are likely to occur around midnight, when snowfall rates could approach 3 to 5 cm per hour, especially between Peterborough and Kingston.

While this will only last for a few hours, that kind of snowfall in such a short timeframe is likely to make travel difficult during the overnight hours as road crews struggle to keep up. The snowfall intensity appears lighter further east around Cornwall and Ottawa, where totals will be more limited.

Lake effect activity is also expected to begin organizing, starting with Lake Huron. There is still some uncertainty around the Georgian Bay component. The system affecting Eastern Ontario could track far enough west to influence wind direction off Georgian Bay, which may delay or even limit the onset of snow squalls in that region.

By the early morning hours of Tuesday, Eastern Ontario will see the steady snowfall taper off as it shifts into Quebec.

Instead, the focus will turn to strengthening lake effect activity off Lake Huron and Georgian Bay. Again, there is some disagreement on how intense the Georgian Bay squall will become. If it does develop properly, it appears most likely to focus somewhere along the Midland to Orillia corridor.

The Lake Huron activity will initially target Bruce and Grey counties, at times extending into northern Huron and Perth counties, along with portions of Wellington and Dufferin counties.

Another major concern is that this lake effect activity will be accompanied by gusts approaching 50 to 70 km/h at times, especially near the shoreline and in flat, exposed areas. That can lead to significant reductions in visibility due to blowing snow and may even briefly meet blizzard criteria in some areas east of Lake Huron.

It is very likely that the usual roads vulnerable to blowing snow across Grey Bruce, Huron and Perth counties may need to be shut down for a period of time on Tuesday. Expect significant delays and consider avoiding travel if possible, especially during the morning and early afternoon.

Heading into Tuesday afternoon, the winds fueling the lake effect activity are expected to gradually diminish, starting with Georgian Bay. That will likely allow any activity off Georgian Bay to slowly fizzle out by early afternoon.

For Lake Huron, the activity is likely to drift south of Grey Bruce and focus more on portions of Huron and Perth counties. It may persist for several hours through the afternoon before weakening closer to the dinner hour.

If the snowfall is not enough to set the winter mood, it will certainly feel like it as a surge of Arctic air settles over Southern Ontario overnight into Tuesday.

Many areas are expected to drop below -10°C by Tuesday morning. With the wind chill, it could feel closer to -25°C in some locations, especially east of Lake Huron into Central Ontario and parts of Northeastern Ontario.

As is usually the case with lake effect snow, it can be very difficult to pinpoint the hardest hit regions. These snow bands can be narrow and highly localized, meaning one community could see significant accumulation while another just down the road sees very little.

With that in mind, the heaviest snowfall totals are most likely somewhere in the Port Elgin, Hanover, Minto, Mildmay, Kincardine, Point Clark and Wingham zones. We are forecasting 20 to 30 cm in this corridor, but there is a chance that localized areas could see as much as 35 to 40 cm if a band locks in place for several hours.

Surrounding areas, including Goderich, Clinton, Exeter, Mitchell, Stratford, Listowel, Arthur, Flesherton, Meaford, Chatsworth, Owen Sound, Wiarton and Lion’s Head could see around 10 to 20 cm. Some of these communities may fall short of that depending on how far inland the lake effect bands extend and how long they persist.

For the Georgian Bay squall, we are forecasting 10 to 20 cm for Midland, Orillia and Washago. Barrie sits right on the line and could go either way. If 10 cm or more falls in Barrie, it would most likely be in the north end, with lesser amounts toward the south. Should the Georgian Bay activity exceed expectations and organize more than current guidance suggests, localized pockets of 25 to 30 cm cannot be completely ruled out. However, it could just as easily struggle to reach 10 cm.

In Eastern Ontario, the system is expected to deliver a general 10 to 15 cm in locations including Peterborough, Belleville, Kingston, Bancroft, Deep River, Renfrew and Pembroke. Some areas, especially north of Lake Ontario between Peterborough and Kingston, may pick up closer to 20 cm where the heaviest snowfall rates set up overnight.

Less than 10 cm is expected for Ottawa, Cornwall and Brockville as these areas are likely to see lighter and less intense snowfall from this system. The same applies to Muskoka and Parry Sound, where 5 to 10 cm is possible.

Lower amounts are expected in the Greater Toronto Area, extending into Hamilton and the Niagara region. Around 2 to 5 cm of snow is expected, mainly during the evening on Monday.

Less than 2 cm is expected for Deep Southwestern Ontario, including Windsor, Chatham and Sarnia, where this system will have very limited impact.

March 14, 2026

Up to 100 cm of Snow Possible as Blockbuster Winter Storm Targets Northern Ontario Starting Sunday With Blizzard Conditions and Ice Storm Risk

March 14, 2026/ Brennen Perry

A powerful and complex storm system is set to impact Ontario beginning Sunday and continuing into early next week. While Southern Ontario will mainly deal with a messy mix of precipitation and rain for much of the event, the situation will be far more serious across parts of Northeastern Ontario, where extremely heavy snowfall, strong winds, and freezing rain could create dangerous travel conditions.

The system will evolve in several phases as it tracks through the region. Snow will initially spread into Northeastern Ontario on Sunday before an influx of warm air begins pushing northward and creating a zone of freezing rain. As the storm gradually moves out of the region on Monday, attention will then turn to the potential for lake effect snow developing late Monday into Tuesday.

Snow will begin spreading into Northeastern Ontario from the southwest during the morning and early afternoon hours on Sunday. At first, the snow may be somewhat light and patchy as the leading edge of the system arrives, but conditions will steadily deteriorate through the afternoon as more intense bands move into the region.

These bands will become particularly strong late Sunday afternoon and evening as the storm reaches peak intensity. Within the heaviest bands, snowfall rates could exceed 5 cm per hour. These intense bursts of snow will quickly overwhelm roads and dramatically reduce visibility.

Strong winds will also play a major role in this storm. Wind gusts of 60 to 90 km/h are expected to develop Sunday afternoon and continue into the overnight hours. When combined with the intense snowfall, these winds will lead to widespread blowing snow and periods of blizzard conditions.

Travel could quickly become extremely hazardous across parts of Northeastern Ontario. Visibility may frequently drop to near zero in the heaviest snow bands and blowing snow. There is a strong likelihood that highways could become impassable at times, and widespread highway closures are possible in the hardest hit regions.

Looking at the snowfall totals, the highest accumulations are expected across parts of central Northeastern Ontario. Areas stretching from Sault Ste. Marie, through Chapleau, Timmins and Kirkland Lake could see between 60 and 100 cm of snow.

Totals will gradually drop off to the north as the core of the system remains farther south. This means communities such as Wawa, Kapuskasing and Cochrane could see between 40 and 60 cm of snow by the time the storm begins to wind down.

Farther south, the story becomes more complicated as ice pellets and freezing rain begin mixing in and reducing snowfall totals. A narrow corridor from Elliot Lake to Temiskaming Shores is currently expected to see between 40 and 60 cm of snow before the changeover occurs.

For areas from Espanola through Sudbury, snowfall totals will likely be closer to 25 to 40 cm. North Bay is expected to see around 10 to 15 cm of snow, most of which will fall during the afternoon on Sunday, before precipitation transitions over to ice pellets and freezing rain.

While snowfall will gradually lighten during the day on Monday across Northeastern Ontario, conditions may still remain difficult in many areas due to deep snow on the ground and lingering blowing snow.

While heavy snow dominates the northern portion of the storm, the next major concern will be the development of freezing rain as warmer air begins pushing northward Sunday evening.

The leading edge of the system will first sweep across Southern Ontario early Sunday, bringing a light mix of wet snow, freezing rain and ice pellets. This initial wave is not expected to produce significant accumulation, but it could still create slippery road conditions during the morning and afternoon as it moves through.

Behind this initial batch of precipitation, much warmer air will surge northward into Southern Ontario through Sunday afternoon and evening. This will transition most areas over to plain rain while the storm continues to produce heavy snow farther north.

As this warm air pushes into the colder air mass across Northeastern Ontario, it will create a corridor favourable for freezing rain. By Sunday evening, a swath of freezing rain is expected to develop, extending from Manitoulin Island through the North Bay region.

Through the late evening and overnight hours, this freezing rain zone is expected to gradually spread northward. Communities, including Elliot Lake and Sudbury, could transition from heavy snow to freezing rain by late Sunday evening.

Within this corridor, freezing rain could become quite significant in some areas, with ice accretion totals potentially reaching 10 to 20 mm. That may lead to power outages and tree damage, especially with the strong wind gusts.

Freezing rain may continue through much of the overnight period and into the morning hours on Monday before temperatures gradually begin to rise.

Across Southern Ontario, the story will shift again on Monday as milder air remains in place for much of the day.

Scattered rain showers and even a few thunderstorms are possible across parts of the region on Monday. However, temperatures may begin to cool later in the day, which could allow precipitation to transition back to snow in some areas.

Exactly how much snow may develop during this transition remains uncertain. A separate detailed forecast will be issued for Southern Ontario once forecast models provide better clarity on how persistent this snow could be and whether meaningful accumulation is likely.

One additional feature we will be watching closely is the potential for lake effect snow developing late Monday into Tuesday.

As colder air moves back into the region behind the storm system, lake effect snow bands could begin forming off Lake Huron and Georgian Bay. These bands may bring an additional 10 to 20 cm of snow to parts of the traditional snowbelt regions, depending on how long they persist.

March 12, 2026

Winter Makes a Comeback Friday with Up to 15cm of Snow Possible Across Southern Ontario

March 12, 2026/ Brennen Perry

While we started off the week with a taste of spring-like weather across Southern Ontario, with widespread double-digit temperatures and even readings soaring near 20°C in some areas, the end of the week will bring us back to reality. And that reality is that winter is far from finished!

An Alberta Clipper is set to slide across the region starting Friday morning and persist throughout much of the day. This system is expected to bring a few hours of heavier snowfall with hourly rates approaching 2 to 3cm through parts of Southwestern Ontario and into the Golden Horseshoe.

That rapid accumulation is expected to occur during the late morning and early afternoon hours, which unfortunately lines up with a very busy time of day. This will set up messy conditions just in time for the afternoon commute, especially on untreated roads and highways.

Drivers should be prepared for rapidly changing conditions with snow quickly covering roads in areas that experience the heavier bursts.

This heavy snow will also be accompanied by strengthening winds with gusts approaching 50 to 70 km/h across many areas. Even stronger gusts are expected around Lake Huron, where some locations could see gusts approaching 80 km/h.

Those strong winds combined with the falling snow will likely create near zero visibility at times on the roads due to blowing snow. In some exposed rural areas, there could even be localized blizzard conditions developing for a time, particularly where open farmland allows the wind to easily pick up and blow the snow around.

Once the system wraps up late Friday into early Saturday morning, most of Southern Ontario will be looking at around 10 to 15cm of fresh snow. That will bring back a familiar winter landscape that was wiped out in many areas thanks to the warm temperatures earlier this week.

The first bands of snow are expected to begin working their way into Southwestern Ontario from the west just after sunrise on Friday morning.

That means locations around Lake Huron will likely be the first to experience the steady snowfall. The snow should start out fairly light early in the morning before gradually increasing in intensity.

For Deep Southwestern Ontario around the Windsor and Chatham area, it looks like they will be sitting right near the freezing mark. These areas could start off with some flurries during the pre-dawn hours, but little accumulation is expected.

As temperatures rise above freezing through the morning hours, precipitation will likely switch over to rain by the late morning, which will limit any snowfall accumulation in this region.

That swath of snow will pick up intensity through the late morning with it spreading eastward into the Greater Toronto Area and regions around Lake Simcoe by around the noon hour. As this occurs, snowfall rates are expected to increase across parts of the region.

It appears that an area of elevated snowfall rates approaching 2 to 3cm per hour could briefly set up in regions east of Lake Huron and into the Golden Horseshoe. Even though this intense snowfall would only last for a few hours, it could still lead to some rapid accumulation in a short period of time.

That burst of heavier snow could lead to some quickly deteriorating road conditions leading up to the afternoon commute and make for some slushy and snow covered roads.

It should be mentioned that temperatures in many of these areas will be sitting very close to the freezing mark. Because of that, it is possible that accumulation may not be as efficient as it would be during colder snowfall events.

Some of the snow may melt as it falls or shortly after reaching the ground, especially on roadways that were warmed by the recent mild weather.

We may even see some mixing along the Lake Erie and Lake Ontario shoreline, especially toward the mid to late afternoon hours when temperatures may briefly creep above freezing.

**wind gusts (km/h)** - MAP FROM WEATHERBELL

Another big factor that will enhance the impact of what would normally be considered a fairly uneventful snowfall event is the wind.

Earlier forecast data suggested much stronger and more widespread wind gusts, but recent model runs have toned those values down somewhat.

Even with that reduction, winds are still expected to be quite gusty with gusts near 50 to 70 km/h across Southwestern Ontario and the Golden Horseshoe. Closer to Lake Huron those gusts could approach 80 km/h at times.

Given the heavier snowfall rates of 2 to 3cm per hour at times, these gusts will likely lead to near zero visibility in some areas with widespread blowing and drifting snow developing.

There could even be some localized blizzard conditions east of Lake Huron, which is particularly vulnerable due to its exposed rural roads and open terrain. In these areas, snow can easily be picked up by the wind and blown across roadways, quickly reducing visibility and creating hazardous driving conditions.

Road closures cannot be ruled out in some of the more exposed locations, especially if blowing snow becomes intense during the peak of the storm.

Heading into the late afternoon hours, the snow will have spread into Central and Eastern Ontario, where it is expected to persist into the evening. Some of the areas further east may not see the snow fully taper off until early Saturday morning as the system gradually exits the region.

It appears that the overall intensity of the snow will slowly decrease by the evening hours, with snowfall rates closer to 1 to 2cm per hour in many areas.

The heaviest pockets during the evening appear to be focused on areas north of Lake Ontario such as York Region, Durham Region, Kawartha Lakes and Peterborough before eventually moving into parts of Eastern Ontario after the dinner hour. Hourly snowfall rates in these areas could still briefly exceed 2cm at times through the evening before gradually easing overnight.

For Southwestern Ontario and the Greater Toronto Area along the Lake Ontario shoreline, rising temperatures near the shoreline will likely lead to a switch from snow to rain by the late afternoon and early evening. This changeover will help limit snowfall totals closer to the lakes.

Another wave of light snow may move in from the west late in the evening and into the overnight hours as colder air flows in behind the departing system. However, this additional snow is not expected to produce significant accumulation.

We are also watching the evening hours closely for Deep Southwestern Ontario, where stronger wind gusts may develop just before midnight.

There is the potential for gusts reaching 80 to 90 km/h for areas such as Windsor, Chatham and Sarnia.

It is even possible that a few isolated severe wind gusts exceeding 90 km/h could occur in localized areas if the strongest winds are able to mix down to the surface.

Overall, we are looking at general snowfall amounts of 10 to 15cm across much of Southern Ontario by Saturday morning.

A few pockets, especially in higher elevation areas like northwest of the Greater Toronto Area and the Dundalk Highlands, could see localized totals approaching 20cm thanks to slightly colder temperatures that will allow snow to accumulate more efficiently.

The 10 to 15cm zone includes Goderich, Kincardine, Owen Sound, Wiarton, Tobermory, Hanover, Orangeville, Kitchener, Guelph, Newmarket, Barrie, Collingwood, Midland, Orillia, Bracebridge, Parry Sound, Huntsville, Peterborough, Bancroft, Pembroke, Renfrew, Smiths Falls and Ottawa.

Slightly lower totals of 5 to 10cm are expected from London into the Niagara region and around the Greater Toronto Area near the Lake Ontario shoreline, continuing east into Kingston and up along the St. Lawrence River.

Temperatures are expected to rise above freezing in this corridor, especially during the afternoon hours, which could reduce the ability for snow to accumulate and even allow some rain to mix in at times.

That includes Grand Bend, London, St. Thomas, Tillsonburg, Niagara Falls, Hamilton, Mississauga, Toronto, Oshawa, Belleville, Picton, Kingston, Brockville and Cornwall.

To the north, lower snowfall totals of 5 to 10cm are also expected in locations such as Algonquin Park, Deep River, North Bay, Sudbury and Elliot Lake. This is mainly because the heavier precipitation bands are expected to stay south of these regions.

Around 2 to 5cm is expected for Sarnia and Chatham as they see rain for much of the event, with less than 2cm likely for the Windsor and Leamington area, where temperatures remain warm enough for precipitation to fall primarily as rain.

March 10, 2026

Major Ice Storm Targeting Ottawa Area Wednesday, Up to 25mm of Freezing Rain Threatens Power Outages Across Central and Eastern Ontario

March 10, 2026/ Brennen Perry

A complex weather story is set to unfold across Southern Ontario over the next 24 hours as cold and warm air clash across the region while a moisture-laden system moves through.

The biggest impact will come in the form of a concerning prolonged ice storm event across parts of Central and Eastern Ontario. In some areas, this freezing rain could be nearly non-stop for much of Wednesday, leading to up to 24 hours of persistent icing. The worst of the freezing rain is expected to begin overnight Tuesday and continue into Wednesday morning, with a second round arriving later in the day.

The Ottawa Valley and northern sections of Eastern and Central Ontario appear likely to take the brunt of the ice storm, with up to 15-25mm of ice accretion possible. That amount of ice is more than enough to cause substantial damage to infrastructure, raising the threat of widespread and potentially prolonged power outages that may last for days or even weeks.

To make matters worse, some of those hardest hit areas may remain below freezing for the entire duration of the event before temperatures plunge even further late Wednesday as colder air floods in behind the system. This would lock in the ice accretion and allow it to continue weighing down trees and power lines for the foreseeable future. Stronger winds gusting in excess of 50 km/h early Thursday could add additional strain and prompt even more power outages.

For other parts of Southern Ontario, the story will be some noisy nocturnal thunderstorms moving in early Wednesday morning from Michigan. While these storms should remain sub-severe for the most part, they could still produce strong wind gusts that may briefly reach marginally severe levels in a few pockets. Another concern is that this rain could further exacerbate the ongoing spring flooding that is already leading to higher water levels in many watersheds, with widespread 15–30mm of additional rainfall on tap.

After this system moves out, we are set to enter a cooler and more active pattern beginning with a potential snowy system on Friday. Confidence remains fairly low in the exact setup, and some mixing could reduce snowfall totals, especially near the shorelines of Lake Ontario and Lake Huron. However, it could still deliver a widespread 5-15cm of snow, bringing back a snowy landscape that has been melted away in many areas over the past few days.

Current indications suggest the leading edge of the system will begin to move into Southwestern Ontario around or just after midnight. That will arrive in the form of heavy rain and embedded thunderstorms stretching across Lake Huron. These storms are actually part of a larger line that merged from earlier severe activity over Illinois and Indiana, where a severe weather outbreak is underway Tuesday evening.

However, by the time these storms reach our region, and especially given that they will need to travel over the cold waters of Lake Huron, we expect they will have weakened considerably by landfall.

There is still an outside chance that a few embedded cells could remain strong enough to produce a marginal wind threat, particularly around Windsor and Sarnia, but that scenario remains very questionable.

Regardless of their strength, these storms will likely wake many residents up overnight thanks to frequent lightning and very heavy downpours.

Further north, the system will encounter a pocket of below-freezing temperatures over the Bruce Peninsula. With warm air in place above the surface, this will allow a swath of freezing rain to develop starting over the Northern Bruce Peninsula and spreading eastward into areas east of Georgian Bay during the pre-dawn hours.

This icing could be quite heavy at times and may even feature some embedded lightning. Across the Sudbury and North Bay areas, precipitation should initially remain on the snow side with some ice pellets mixed in.

In advance of the system, we may also see some scattered freezing drizzle develop late Tuesday evening and continue into the overnight hours across parts of Central and Eastern Ontario.

That swath of freezing rain will continue to progress eastward, with the freezing line roughly located from Bracebridge to Brockville.

Locations just to the south of this line, such as Midland, Orillia, Lindsay and Peterborough, may begin with some freezing rain, but precipitation should quickly transition over to rain as the warmer air advances northward through the mid-morning hours.

This setup will allow the most intense icing to occur from Parry Sound through Huntsville and into Bancroft just before sunrise. It should be noted that some northern sections, such as Algonquin Park, Pembroke and Sundridge, could remain just cold enough to keep some precipitation falling as ice pellets before reaching the ground. This would delay the onset of icing somewhat and reduce overall ice accretion in those locations.

Meanwhile, the line of thunderstorms will continue tracking through Southwestern Ontario, slowly weakening as it approaches the Golden Horseshoe while still producing lightning and heavy rain. This rainfall could be quite intense at times and may lead to rapid accumulation, putting further strain on already saturated watersheds due to ongoing spring runoff. That could trigger additional flooding in some low-lying areas.

By mid-morning, the heavy freezing rain is expected to move into the Ottawa Valley, where it may persist through the late morning hours, bringing rapid ice accretion. Travel could quickly become treacherous for the morning commute in the Ottawa area, and within a few hours, the accumulating ice will likely begin taking a toll on the power grid.

We may also see the freezing rain line nudge northward into North Bay and Sudbury as warmer air aloft continues to expand northward despite the colder air at the surface remaining stubborn.

For the southern parts of Central Ontario, such as Bracebridge, Haliburton and Kawartha Lakes, it appears the warm air will eventually be able to overcome the cold air near the surface. This would allow these areas to escape the worst impacts, although they remain right on the line. If the cold air proves more stubborn than expected, it could keep these areas in freezing rain for several additional hours.

That will likely not be the case farther north across Central and Eastern Ontario, including much of the Ottawa Valley, where models suggest the freezing line will stall to the south.

There remains some disagreement among the models regarding exactly how far north the warmer air will be able to advance. The best chance for temperatures to rise above freezing appears to be along the St. Lawrence River and southeast of Ottawa.

While precipitation should briefly lighten to drizzle by early afternoon as the first round moves into Quebec, additional steady precipitation will begin advancing from the southwest. This second round appears less intense than the first and will likely be light to moderate rather than a continuous downpour of freezing rain.

That precipitation should reach the Ottawa Valley by late Wednesday afternoon, with persistent freezing rain potentially continuing through the evening and into the early morning hours of Thursday. However, the precipitation should become more scattered after midnight, gradually tapering off to drizzle.

Some parts of the Ottawa Valley may briefly rise above freezing, particularly near the southern edge of the ice storm risk around Bancroft, Smiths Falls and Cornwall. If that occurs, it would reduce the overall impact in these areas, although the temperature gradient will be extremely tight.

The hardest hit regions for freezing rain are expected to encompass a large portion of Eastern Ontario along the Quebec border and into the Ottawa Valley. In these areas, total ice accretion is likely to range from 15 to 25mm with localized amounts approaching 30mm.

That includes Ottawa, Hawkesbury, Alexandria, Carleton Place, Perth, Arnprior, Renfrew, Cloyne, Bancroft, Haliburton, Barry’s Bay and Pembroke.

However, keep in mind that actual surface accretion may end up somewhat lower since a large portion of the precipitation will fall during a short timeframe. Some of it may drip off surfaces before it has time to fully freeze when it arrives in heavy bursts.

Another major factor will be whether any areas are able to briefly climb above the freezing mark during the afternoon before the arrival of the second wave of precipitation. If that occurs, some of the earlier ice could melt away and make the second round far less efficient when it comes to additional ice accretion.

That is why this event could easily end up being far less damaging than currently forecast if temperatures trend just slightly warmer. There is often very little middle ground when it comes to ice storms, which is why there is such a tight gradient in our forecast ice totals.

Current projections suggest around 10-15mm of ice for northern sections of Central Ontario, including Parry Sound, Burk’s Falls, Huntsville, Algonquin Park and Deep River. This also extends into the Northern Bruce Peninsula. The slightly lower ice totals are due to temperatures potentially rising near Georgian Bay before the arrival of the second round of precipitation, along with the possibility of ice pellets mixing in farther north.

A similar situation may occur just south of the core ice storm zone, including Apsley, Kaladar, Smiths Falls, Kemptville and Cornwall. We expect the freezing line to eventually reach these areas by the afternoon, shutting off the freezing rain threat and substantially limiting the overall impact compared to locations farther north.

Further south, we are expecting around 5-10mm of ice from Bracebridge through Havelock, Tweed and into Morrisburg. Again, these areas should eventually rise above freezing, which will limit the impact mainly to the morning hours when icing is most persistent.

Across the Midland and Gravenhurst to Fenelon Falls corridor extending eastward toward Brockville, freezing rain should be more brief, primarily during the morning hours, leading to roughly 2-5mm of icing at most. We may also see around 2mm of icing in the higher elevations of the Dundalk Highlands, including Orangeville and Shelburne and extending into the Blue Mountains, although it remains uncertain if temperatures will be cold enough here for significant icing.

Very little icing is expected once you reach Lake Simcoe and areas stretching toward Kingston along the Lake Ontario shoreline. This includes Orillia, Lindsay, Peterborough and Belleville. There may be a brief one to two-hour window of freezing rain early in the morning, but temperatures should quickly rise above freezing. Less than 2mm of ice accretion is expected.

**max wind gusts (km/h)** - MAP FROM WEATHERBELL

While the freezing rain should taper off overnight Wednesday, the impacts may continue into Thursday in areas where earlier ice accretion remains locked in place as temperatures drop once again overnight. Ice-covered trees and power lines will remain vulnerable to wind due to the additional weight from the ice.

Unfortunately, stronger wind gusts could develop early Thursday morning with gusts potentially reaching 60-80 km/h in parts of Eastern Ontario. If significant ice remains in place, that would be a recipe for substantial damage to the power grid.

It also does not appear that the ice will be melting anytime soon. The pattern into next week looks to feature mostly below freezing temperatures across Eastern Ontario with wind chills dropping into the negative teens. That could make for dangerous conditions if widespread power outages occur and many homes are left without heat.

**rainfall totals (mm)** - MAP FROM WEATHERBELL

As for rainfall totals, we are expecting generally around 15-30mm across Southwestern Ontario and into the Golden Horseshoe. Localized pockets could see up to 50mm thanks to persistent thunderstorm activity, particularly along the Lake Erie shoreline.

Looking ahead to Friday, we are also monitoring a potential widespread snowfall event across much of Southern Ontario.

There is still considerable uncertainty regarding who may see the heaviest snowfall due to the potential for rain mixing in depending on the exact track of the system. However, current indications suggest the heaviest snow could fall across Central and Eastern Ontario, where up to 5-15cm may accumulate throughout the day on Friday.

With Eastern Ontario likely still recovering from the ice storm, that snowfall could add even more weight to already weakened trees and infrastructure. This may lead to another round of falling branches and potentially additional power outages.

More details on Friday’s system will be provided in a separate forecast later this week.

March 09, 2026

Damaging Ice Storm Risk for Ottawa, Eastern and Central Ontario Tuesday Night Into Wednesday

March 09, 2026/ Brennen Perry

Over the past few days, Southern Ontario has been treated to an early taste of spring-like weather. Temperatures soared well into the double digits across many areas, and some locations even managed to hit the 20°C mark for the first time this season.

After experiencing such a dramatic warm-up, it’s hard to imagine how quickly we could be plunging right back into the grip of winter. But it’s important to remember that we are only in early March. This time of year is well known for dramatic swings in the weather, and that reality will become very apparent across Central and Eastern Ontario over the next couple of days.

A moisture-packed system is set to slide through Southern Ontario beginning late Tuesday and continuing through Wednesday. This system will bring a wide variety of weather conditions depending on where you are located, ranging from heavy rain and thunderstorms in the south to a prolonged freezing rain threat further north and east.

Those in Southwestern Ontario and the Golden Horseshoe will continue to enjoy the milder temperatures in the double digits on Tuesday and Wednesday. With temperatures remaining well above freezing in these areas, the main focus will be on periods of heavy rain along with the potential for some thunderstorm activity.

With snowmelt already well underway or even complete following the recent warmth, this additional rainfall could further exacerbate ongoing flooding concerns in some areas. Localized flooding in low-lying areas and near rivers and creeks will remain something to watch closely through midweek.

Further north, this system is likely to encounter some colder air that will become entrenched across Central and Eastern Ontario. This will create a very sharp temperature divide across the province, with areas to the south seeing spring-like conditions while areas further north sit much closer to the freezing mark or even slightly below.

These below-freezing surface temperatures combined with warm air aloft will provide the perfect setup for freezing rain. Multiple waves of precipitation are expected to move through the region, creating the potential for a prolonged freezing rain event.

This pocket of cold air appears like it may become quite entrenched, particularly across Eastern Ontario and the Ottawa Valley. As a result, some areas could be dealing with freezing rain for 12-24 hours or even longer if the cold air proves stubborn enough to hold on.

If this scenario plays out, it could lead to ice accretion totals of at least 10mm with localized pockets potentially exceeding 25mm. Amounts like this would be more than enough to result in crippling impacts across parts of Eastern Ontario, including tree damage, widespread power outages and extremely hazardous driving conditions.

The worst icing currently appears likely to arrive in two waves. The first wave is expected to impact Central and Eastern Ontario overnight Tuesday and into Wednesday morning.

Later in the day on Wednesday, a second round of precipitation will move through during the late afternoon and evening hours. By this point, areas across Central Ontario and the southern portions of Eastern Ontario may have risen above the freezing mark, which would limit their impacts mostly to the morning hours.

There remains some uncertainty regarding whether the warmer air will be able to overcome the cold air at the surface during the afternoon on Wednesday. If temperatures manage to climb even slightly above freezing for a few hours in the Ottawa Valley, it could make a huge difference.

Even a brief period of above-freezing temperatures would allow some of the ice from the first wave to begin melting before the second round arrives. That could significantly reduce the risk of this becoming a truly destructive ice storm.

This detail will be particularly important because temperatures are expected to plunge again later Wednesday and could remain below freezing for at least the next few days. If no melting occurs beforehand, all of that accumulated ice would remain locked in place and could lead to prolonged impacts on trees and the power grid.

Before the main system arrives, some scattered showers and drizzle may begin developing on Tuesday afternoon across parts of Southern Ontario. Most areas should remain above freezing, but a small pocket along the northern edge of Central Ontario, including Huntsville, Algonquin Park and Pembroke, could be sitting very close to the freezing mark.

If that happens, some of the drizzle could freeze on contact with surfaces during the afternoon and evening hours ahead of the main system. While any ice accumulation should remain fairly minimal, it could still create some slick road conditions and add a thin layer of ice before the heavier precipitation arrives overnight.

The first wave of heavier precipitation is expected to slide into Southern Ontario from the west just after midnight Tuesday night. It will then continue spreading eastward through the overnight hours and into early Wednesday morning.

For Southwestern Ontario, it could end up being a rather noisy night. Some nocturnal thunderstorms may move through, especially closer to the Lake Huron and Lake Erie shorelines.

Despite the thunderstorms, temperatures in this region will remain well above freezing, so there are no concerns for freezing rain here.

Further north and east, however, colder air closer to the freezing mark will likely be found along the higher elevations near the Golden Horseshoe, including the Dundalk Highlands. This colder air will extend into Central and Eastern Ontario from around Lake Simcoe through Peterborough and into Kingston.

Models are still disagreeing on just how extensive this below-freezing pocket will be. Some guidance keeps it fairly localized to the Dundalk Highlands, including areas like Orangeville and Shelburne.

Other models suggest a few hours of freezing rain could extend across a much larger area, including parts of the northern GTA, Simcoe County, Peterborough and Kingston.

Regardless of how far south the freezing rain extends, it is expected to be fairly short-lived in these areas as temperatures should rise above freezing by the late morning hours on Wednesday, switching precipitation over to plain rain.

The primary problem area continues to look like a corridor stretching from the Bruce Peninsula through Muskoka, Haliburton, Bancroft and into the Ottawa Valley.

Current indications suggest the cold air will hold on much longer in this region, and in the case of the Ottawa Valley, temperatures may struggle to rise above freezing at all throughout the day on Wednesday.

As a heavy pocket of freezing rain moves through, starting across Central Ontario during the mid-morning hours and reaching the Ottawa Valley by late morning, substantial ice accretion could begin to build quickly.

Precipitation rates may become quite heavy at times, which adds another layer of uncertainty when it comes to ice accumulation. During intense bursts of freezing rain, some of the liquid can drip off surfaces before it has time to freeze.

Even so, conditions are expected to become treacherous through the morning and into the early afternoon across parts of Central and Eastern Ontario. Ice will rapidly build up on tree branches, power lines and other exposed surfaces.

**ESTIMATED TEMP** - MAP FROM WEATHERBELL

One of the biggest challenges with forecasting freezing rain events is that the setup requires a very specific temperature profile. If models are off by even a single degree, it can dramatically change the outcome.

Just a small temperature difference can mean the difference between a crippling ice storm and a much less impactful rainfall event.

This system is no exception. There are some subtle but important differences between the model solutions that could significantly alter the final outcome.

Most models show above freezing temperatures gradually pushing northward into Central and Eastern Ontario beginning late Wednesday morning and into the early afternoon. The key question is how far north the warmer air will be able to penetrate.

The American model is the most aggressive with the warm air, pushing the freezing line as far north as Bancroft and even Ottawa. If that scenario occurs, locations including Muskoka, Haliburton, Smiths Falls, Brockville, Cornwall and parts of Ottawa could briefly rise above freezing and bring an end to the freezing rain threat by early afternoon.

The Canadian model, on the other hand, keeps the cold air much more entrenched across the Ottawa Valley. In that scenario, temperatures remain below freezing through the afternoon, which would allow freezing rain to continue and prevent any earlier ice accumulation from melting away.

Even if some areas do briefly rise above freezing during the afternoon, that warm-up will likely be short-lived.

Colder air is expected to wrap back into the system as a second round of precipitation moves through Central and Eastern Ontario during the late afternoon and early evening hours.

Current indications suggest the mixing line may set up somewhere around Muskoka, extending eastward through Bancroft and into the Brockville area.

This would allow another swath of heavy freezing rain to develop across the Ottawa Valley, which could add even more ice accumulation and further amplify impacts during the evening hours. This should taper off around midnight, switching to light snow overnight into Thursday morning.

For Southwestern Ontario, there is also the possibility of some freezing rain or snow mixing in toward the later part of Wednesday as colder air wraps in behind the departing system. At this point, however, any wintry precipitation in the southwest is not expected to be significant.

When it comes to the hardest hit areas, we are currently looking at ice storm level impacts potentially developing across much of Eastern Ontario. This includes communities such as Ottawa, Hawkesbury, Alexandria, Cornwall, Kemptville, Carleton Place, Smiths Falls, Perth, Arnprior, Renfrew, Bancroft, Pembroke, Barry’s Bay, Haliburton and Minden.

General ice accretion across this region could range from 10 to 25mm with localized pockets, especially east of Ottawa, closer to the Quebec border, potentially exceeding 25mm.

As mentioned earlier, locations along the southern edge of this zone, including Perth, Smiths Falls, Kemptville and Cornwall, could see somewhat lower ice totals if temperatures briefly rise above freezing during the late morning and afternoon hours.

Outside of the ice storm zone, prolonged freezing rain is still expected across much of Central and Eastern Ontario, roughly north of a line from Orillia to Brockville.

This includes areas such as Brockville, Westport, Kaladar, Havelock, Fenelon Falls, Gravenhurst, Bracebridge, Huntsville, Parry Sound, Burk’s Falls and Sundridge.

Ice accretion in these areas will likely range from 5 to 15mm, with most of the accumulation occurring during the morning hours on Wednesday before temperatures rise above freezing later in the day.

Exactly how quickly this switchover to rain occurs will determine the final ice totals. A faster transition to rain would likely keep totals closer to 5mm, while a slower warm-up could allow some areas to approach 15mm.

Some brief freezing rain during the pre-dawn hours on Wednesday is also possible for locations including Midland, Orillia, Lindsay and Kingston. However, it should remain very minor as temperatures are expected to rise above freezing fairly quickly, switching precipitation over to rain after an hour or two.

The higher elevations of the Dundalk Highlands may be able to hold onto below-freezing temperatures for a few additional hours. Areas such as Orangeville and Shelburne could see around 2 to 6mm of freezing rain accumulation, mostly during the morning hours.

Once temperatures climb above freezing, though, impacts in these areas should quickly improve.

In locations that remain mostly rain, we are generally expecting between 20 and 40mm of rainfall across Southwestern Ontario and into the Golden Horseshoe.

Localized heavier pockets of 50 to 75mm are possible closer to the Lake Erie shoreline, especially in areas that see thunderstorm activity develop within the system.

Keep in mind that this remains a preliminary forecast, and details may still shift before the system arrives. We will have a much more refined forecast on Tuesday with updated timing and precipitation totals as we get closer to the event.

March 06, 2026

Southern Ontario Could Soar Near 20°C This Weekend as ‘March Melt’ Triggers Rapid Snowmelt, Flooding Risk and Thunderstorms

March 06, 2026/ Brennen Perry

After what felt like a winter that would never end across Southern Ontario, our first widespread taste of spring-like weather is finally on the horizon just in time for the weekend.

While parts of Southwestern Ontario have already seen brief stretches of double-digit temperatures this year, those warmer readings have been fairly localized. That is about to change on Saturday as temperatures are expected to soar well into the double digits across most of Southern Ontario. There is even a chance that Deep Southwestern Ontario could see the first 20°C day of the year.

Unfortunately, this warm-up will come at a cost. The milder temperatures will arrive alongside heavy rainfall and embedded thunderstorm activity beginning Friday evening and continuing through much of Saturday.

As the warmer air moves in, it will also bring a more unstable atmosphere. Because of this, there is a conditional risk for marginally severe storms in parts of Southwestern Ontario extending toward the Niagara region. There remains quite a bit of uncertainty with this threat, as storms will have to contend with the very cold waters of Lake Huron and Lake Erie, which can act as a natural storm shield for Southern Ontario.

Another concern with this system is the flooding potential. The combination of double-digit temperatures and heavy rainfall over an area that still has a fairly significant snowpack, especially across Central Ontario, could lead to rapid snowmelt and rising water levels.

Current model guidance suggests that this brief warm spell could trigger rapid melting of the snowpack. This would introduce a large amount of additional water into local rivers and watersheds on top of the 25 to 50 mm of rainfall that is expected from this system.

Those in areas that are prone to spring flooding should begin preparing for the possibility of rising water levels over the next several days into early next week. As the snowpack melts and rain continues to fall, that water will gradually work its way through the watershed. Additional rainfall toward the middle of next week, combined with another round of double-digit temperatures, could further worsen the situation.

The first round of heavier rainfall is expected to develop late Friday and continue into the overnight hours. This area of rain may also contain embedded non-severe thunderstorms, particularly around Lake Huron and Georgian Bay, extending eastward into parts of Eastern Ontario.

These pockets of storms may produce locally heavier rainfall totals along with small hail and frequent lightning strikes.

By mid-morning on Saturday, areas from Southwestern Ontario into the Greater Toronto Area should see a brief break from the heavier rainfall. Periods of drizzle may continue through the rest of the morning while the focus for heavier rain and thunderstorms shifts toward Eastern Ontario before gradually moving out by around the lunch hour.

Another cluster of heavy rain and embedded thunderstorms is expected to develop and move into Southwestern Ontario sometime during the late morning or early afternoon hours. There remains some disagreement among forecast models regarding the exact intensity of this line as it crosses Southern Ontario.

It cannot be ruled out that a marginally severe storm could develop within this cluster. The main threats would be damaging wind gusts and large hail. This risk appears to be slightly higher around the Niagara region, where storms could move into an environment that becomes more favourable for severe weather through the early to mid-afternoon hours.

After this cluster moves through, there is also the possibility of additional isolated storms developing over Michigan and Lake Huron. These storms could then track into Southwestern Ontario by the late afternoon or early evening hours.

This time period may present the greatest severe weather potential of the day. However, there is still uncertainty related to the timing of the earlier cluster of storms. If that earlier activity clears out quickly enough, it would allow the atmosphere time to recover and become unstable again by late afternoon, creating a more supportive environment for additional storm development.

Another important factor is the time of year. This would be our first thunderstorm risk of the season, and the lakes remain extremely cold. When storms move over these cold waters, they often weaken, which can limit their ability to become severe. This is one reason why early-season storm risks across Southern Ontario often underperform expectations.

Because of this uncertainty, we are currently forecasting a level 1 out of 5 severe weather risk, also known as a marginal risk. This represents the potential for storms capable of producing wind gusts up to around 90 km/h, hail up to quarter size and brief heavy rainfall. While the tornado risk appears to be fairly low, it can never be completely ruled out when dealing with severe thunderstorms.

Locations within the marginal risk area include Windsor, Chatham, Sarnia, London, Grand Bend, Goderich, Kincardine, Owen Sound, Hanover, Brantford, Hamilton and Niagara Falls.

Across the rest of Southern Ontario, including the Greater Toronto Area, Central Ontario and Eastern Ontario, there will still be a chance for thunderstorms. However, most of these storms are expected to remain below severe limits and will likely occur during the overnight hours into Saturday morning and early afternoon.

Aside from the thunderstorm threat, heavy rainfall will be a major story with this system. Widespread rainfall totals of 25 to 50 mm are expected across many areas by the end of Saturday.

The heaviest rain is expected to stretch from the Lake Huron shoreline northeastward through Central Ontario and into portions of Eastern Ontario. Most areas within this corridor will likely see around 25 to 40 mm of rainfall, although localized thunderstorms could push totals closer to 50 mm or even as high as 65 mm in isolated locations where storms repeatedly track over the same area.

Deep Southwestern Ontario and parts of the Golden Horseshoe are expected to receive around 10 to 25 mm of rain. However, rainfall totals will be highly variable depending on thunderstorm activity. Some locations could easily exceed 25 mm if stronger storms develop.

**ESTIMATED SNOW DEPTH (CM)** - MAP FROM WEATHERBELL

Even without the snowpack, this amount of rainfall would already be somewhat concerning for early March. In some areas, the ground remains partially frozen, which limits its ability to absorb rainfall efficiently and increases the likelihood of runoff.

The additional concern comes from the amount of snow still on the ground in parts of Southern Ontario. Snow depth remains quite significant across many areas, especially in Central Ontario.

Model estimates indicate that the deepest snowpack is currently located across Muskoka and into Algonquin Park. However, this is only an estimate. Given the amount of lake effect snow that some of these regions received this winter, the true depth may not be fully captured in the model data.

Current estimates suggest snow depths of roughly 50 to 100 cm in the deepest locations. That represents a large amount of stored water that will eventually enter local rivers and streams as melting begins.

With temperatures climbing well into the double digits on Saturday across much of Southern Ontario, including parts of Central and Eastern Ontario, the snowpack is expected to begin melting rapidly. When combined with 25 to 50 mm of rainfall, this could lead to a fairly rapid influx of water into the watershed.

Forecast models disagree somewhat on how quickly the snowpack will melt. The European model is slightly less aggressive with melting, while the American model shows a much more dramatic reduction in snow depth over the weekend.

According to the American model scenario, most of the snowpack across Southern Ontario could largely disappear by the end of Sunday. The only remaining snow would likely be confined to a small pocket around Muskoka with roughly 5 to 20 cm still on the ground.

If this scenario verifies, it would mean that a large portion of Southern Ontario’s snowpack could melt and enter the watershed within about 48 hours. That would represent a significant amount of water moving through the system in a relatively short period of time.

Residents in flood-prone areas, particularly those located near rivers and streams that commonly experience spring flooding, should be prepared for the possibility of rising water levels over the coming week. This concern is especially relevant across Central and Eastern Ontario, where much of the deeper snowpack is located.

In terms of temperatures, the warmest air is expected to arrive on Saturday. Daytime highs will climb well into the double digits by late morning and afternoon across most of Southern Ontario. For many locations, this will likely be the warmest day experienced so far in 2026.

The warmest conditions will likely occur across Deep Southwestern Ontario, including Windsor, Sarnia and Chatham. Current data support temperatures reaching the upper teens and possibly even approaching the 20°C mark for the first time this year. It is still somewhat uncertain whether temperatures will reach that milestone, but if it happens, the Windsor area would be the most likely location.

Across the rest of Southwestern Ontario and into the Golden Horseshoe, daytime highs are expected to reach the mid to upper teens. Areas closer to the shorelines of the Great Lakes, along with higher elevations northwest of the Greater Toronto Area, may end up slightly cooler with highs closer to 12 to 15°C.

Double-digit temperatures should also extend into Central and Eastern Ontario. Highs around 12 to 15°C are expected from Lake Simcoe through Peterborough and into Brockville.

Areas directly along the Lake Ontario shoreline from Oshawa to Kingston will likely remain slightly cooler with daytime highs around 9 to 12°C due to the influence of the cold lake waters.

Across the rest of Central Ontario and Eastern Ontario, including the Ottawa Valley, temperatures are expected to reach the high single digits or low teens, with most areas topping out around 9 to 12°C.

A brief cooldown will arrive late Saturday night as colder air moves back into the region. Overnight lows will fall back near the freezing mark or into the low single digits. Daytime highs on Sunday will struggle to climb out of the single digits for many locations.

However, this cooldown will be short-lived. Double-digit temperatures are expected to return again on Monday, Tuesday and possibly Wednesday as the active weather pattern continues.

February 24, 2026

Poorly Timed Alberta Clipper to Bring Up to 10-20cm of Snow to Southern Ontario Ahead of Wednesday Morning Commute

February 24, 2026/ Brennen Perry

As we enter the final days of February, it appears the month is set to go out like a lion across Southern Ontario. A poorly timed Alberta clipper is expected to sweep through the region overnight Tuesday into Wednesday, bringing a widespread snowfall and a return to more wintry conditions just as many were starting to get used to some slightly milder weather.

While total accumulation with this system is not expected to be overly significant by late February standards, with general widespread amounts of 5 to 10 cm and some localized pockets closer to 15 cm, what makes this event potentially impactful is the timing and how it lines up with the Wednesday morning commute.

The bulk of this snow is forecast to fall during the overnight hours, lasting into early Wednesday morning. That means many roads will be snow-covered with very little time for crews to fully clear and treat surfaces before traffic begins to build.

Even though snowfall rates are not expected to be extreme, the steady nature of the snow will allow it to accumulate on untreated roads, potentially resulting in slow travel, slippery conditions and even some school bus cancellations in areas where backroads remain snow-covered.

Wind gusts approaching 40 to 60 km/h throughout the morning hours could further reduce visibility due to blowing snow, especially in more exposed areas such as regions east of Lake Huron and around Georgian Bay. Even if the snowfall itself is light to moderate, the added wind will make it feel more intense at times and could create brief periods of near whiteout conditions in open stretches of highway and rural roads.

The system snow is expected to wrap up by the late morning hours as the clipper exits our region to the east. However, that will not necessarily mark the end of the story. Behind the system, a surge of colder Arctic air is forecast to move in, briefly reawakening Lake Huron and Georgian Bay. Ice coverage on both lakes has decreased somewhat over the past few weeks, thanks to temperatures running above seasonal norms, and that open water may allow for renewed lake effect snow development.

As the colder air flows over the relatively milder lake waters, some localized pockets of heavier lake effect snow could develop throughout the day on Wednesday. There is still some uncertainty regarding the exact intensity of this activity, particularly given the remaining ice coverage, which can limit how much moisture the bands are able to tap into. In addition, wind direction is expected to shift throughout the day, making it difficult for any one band to lock in over a single community for an extended period of time.

If the lake effect does organize, it could bring an additional 5 to 10 cm of snow on top of the 5 to 10 cm from the clipper system. That means some areas east of Lake Huron and Georgian Bay could be looking at a combined total of 10 to 20 cm by the end of the day Wednesday, especially in communities that see multiple rounds of heavier bursts.

Current indications suggest the initial bands of heavier snow associated with the clipper should move into regions around Lake Huron and Georgian Bay sometime during the mid to late evening hours on Tuesday. It looks to be heaviest around Grey and Bruce counties at first, before slowly expanding eastward through the rest of the evening and into Central Ontario.

Wind gusts will also be increasing through the evening, leading to blowing snow and reduced visibility overnight. Travel could become fairly difficult, particularly in rural areas and on secondary highways, as the heavier snow moves through during the late evening and overnight hours.

By around midnight, most of Southwestern and Central Ontario should be seeing widespread steady snowfall, with the snow stretching into the Greater Toronto Area as well. The GTA is not expected to see the heaviest bands, but steady snow through the overnight hours will still be enough to create snow-covered roads by daybreak.

This snow will not be particularly intense, with hourly snowfall rates generally near or slightly below 1 cm per hour. However, when that steady snowfall persists for several hours overnight, those hourly amounts can add up quickly. A consistent light to moderate snowfall over a 4 to 6-hour window is more than enough to create slick travel conditions by morning.

Once the snow begins in any given area, it should last for roughly 4 to 6 hours before tapering off. In Southwestern Ontario and the Golden Horseshoe, snowfall should come to an end by the mid-morning hours on Wednesday, while areas farther east will see snow lingering a bit longer.

This is also when the snow will begin to push into Eastern Ontario, setting up for ongoing snowfall right at the height of the morning commute in that region. That timing could lead to more noticeable impacts for communities along the St Lawrence River and into the Ottawa Valley, where snow may still be falling steadily as people head to work and school.

Aside from Eastern Ontario, the snow should be mostly done by sunrise across much of Southern Ontario. However, even if flakes are no longer falling, road conditions may still be less than ideal. With snow ending around 3 to 5 AM in many areas, that leaves a narrow window for cleanup operations, especially in regions with extensive rural road networks and less traffic to help pack down and melt the snow.

The exact impacts will vary depending on location. In more urban areas such as the Greater Toronto Area, cleanup on major highways and primary roads should occur relatively quickly, meaning the morning commute will likely be slower than usual but still manageable. In more rural communities, continued blowing snow combined with existing overnight accumulation could be enough to lead to significant travel delays and the possibility of school bus cancellations.

Another factor we will be closely watching is the development of scattered lake effect snow bands by the late morning hours on Wednesday, continuing into the afternoon and evening. These bands appear most likely to focus on areas east of Lake Huron and Georgian Bay, but shifting winds could occasionally push bursts of heavier snow into neighbouring regions.

Because both Lake Huron and Georgian Bay remain partially ice-covered, the available moisture for lake effect development is somewhat limited. That should help prevent the bands from becoming extremely intense or long-lasting. Changing wind direction throughout Wednesday will also reduce the likelihood of a single band sitting over one community for many hours.

That said, wherever a lake effect band does set up, conditions can deteriorate quickly. Heavy snowfall rates and sharply reduced visibility are possible in these localized areas.

There are some indications that northern portions of Grey and Bruce counties could see more persistent lake effect activity later Wednesday and into the early overnight hours. If that scenario materializes, slightly higher totals would be possible in those areas, particularly along the Bruce Peninsula.

Looking strictly at the snowfall totals from the clipper itself, most of Southern Ontario is expected to see around 5 to 10 cm by the time it tapers off Wednesday morning. A few localized spots could approach 15 cm if they happen to sit under a heavier band for a longer period, but those higher totals will be the exception rather than the rule.

Adding in the lake effect component, another 5 to 10 cm is possible through the day on Wednesday for areas east of Lake Huron and Georgian Bay. That would bring combined totals into the 10 to 20 cm range for communities such as Goderich, Kincardine, Hanover, Owen Sound, Wiarton, Tobermory, Midland, Orillia, Bracebridge and Parry Sound.

Lower snowfall totals under 5 cm are expected for Deep Southwestern Ontario, parts of the Niagara region and along the St Lawrence River in Eastern Ontario. The latest data suggests the system will carry less moisture into these areas, and some locations may briefly sit in a dry slot, resulting in lighter and more intermittent snowfall. Even so, localized amounts closer to 8 cm cannot be ruled out where steadier snow manages to develop for a few hours.

Overall, while this Alberta clipper is not shaping up to be a blockbuster winter storm, its overnight timing, steady snowfall and gusty winds will likely be enough to cause headaches for the Wednesday morning commute across parts of Southern Ontario.

February 20, 2026

Up to 20cm of Heavy Snow to Slam Ottawa, Central and Eastern Ontario Friday as Evening Commute Faces Travel Headaches

February 20, 2026/ Brennen Perry

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Our second messy winter storm of the week is lining up for parts of Southern Ontario, and this one looks timed almost perfectly to cause headaches for the Friday evening commute with a burst of heavy snow in some areas and a messy mix in others.

After many communities dealt with significant impacts earlier in the week, there is very little breathing room before this next system arrives. While Wednesday’s storm largely spared much of Central and Eastern Ontario from the worst of it, this next round is expected to target many of those same regions that missed out last time, shifting the focus farther north and east.

This system comes with its own set of challenges. Temperatures will be hovering very close to the freezing mark for a large portion of the day on Friday, and that makes the forecast particularly sensitive. A difference of just a degree or two will determine whether you see cold rain, freezing rain, ice pellets, or heavy wet snow. That small shift in temperature could dramatically change road conditions and overall impacts in a short amount of time.

Some forecast models continue to show a slightly colder solution, which would support more mixing through the late morning and early afternoon hours. That includes a risk of freezing rain and ice pellets, especially across the higher elevations northwest of the Greater Toronto Area and east of Lake Simcoe.

Other models are holding onto slightly warmer air at the surface, which would keep precipitation mainly as rain through that same window and significantly limit any icing threat. This is the fine line we are watching very closely.

What does appear more certain is that colder air will remain firmly in place across northern sections of Central and Eastern Ontario throughout the day. That means once precipitation begins early Friday afternoon in those areas, it should fall predominantly as snow.

With colder air already established, there will be fewer questions about precipitation type and more focus on how heavy the snow becomes and how quickly it accumulates.

Although this storm is not expected to be a long-duration event, its short and intense nature may actually increase the impact. Several hours of heavy snowfall are likely through the late afternoon and evening, particularly across Eastern Ontario.

Snowfall rates could approach 5 cm per hour in the most intense bands, especially around the Ottawa Valley. When snow falls that hard, accumulation can happen rapidly, and visibility can drop off very quickly, creating hazardous travel conditions in a matter of minutes.

Across Southwestern Ontario and into the Golden Horseshoe, the story will look a little different. Precipitation is expected to arrive overnight in the southwest first, spreading northeast through the morning hours.

With temperatures rising slightly overnight and into the morning, much of the area southeast of Lake Simcoe should see mainly rain through the early to mid-morning hours. For many, the first half of Friday may feel more like a cold and damp day rather than a winter storm.

The tricky zone will set up somewhere across southern Central and Eastern Ontario, where that milder air meets the colder air to the north. In this transition zone, we could see a brief period of freezing rain, changing to ice pellets, and then eventually to snow as colder air deepens. That could allow for some localized icing through parts of Simcoe County, Kawartha Lakes, Peterborough and Kingston during the late morning hours, roughly between 9 and 11 AM.

A pocket of near or slightly below freezing temperatures may also develop along the higher elevations of the Dundalk Highlands around Orangeville.

Not all guidance supports this icing scenario. Some models keep temperatures just above freezing long enough to prevent freezing rain from developing, limiting the risk to plain rain before a changeover to snow later in the day.

Others lean more toward an ice pellet mix rather than significant freezing rain, as colder air aloft begins to erode the warm layer needed to sustain icing. This is where small temperature differences will make a big impact on the ground.

By around midday, the leading edge of steadier precipitation should be pushing deeper into Central and Eastern Ontario. As it runs into that stubborn pocket of cold air across northern sections and into the Ottawa Valley, a swath of heavy wet snow is expected to develop. This band is likely to stretch from Muskoka through Peterborough and into Kingston, gradually intensifying through the afternoon.

There may be some initial mixing with ice pellets that limits accumulation during the first couple of hours, but as colder air continues to settle in, snowfall rates are expected to increase.

Conditions will begin to deteriorate more rapidly later in the afternoon as heavier bands organize. Snowfall rates of 2 to 4 cm per hour appear likely through much of Central and Eastern Ontario, with the heaviest corridor from Lake Simcoe through Peterborough and into Kingston. Snow will also expand into the Ottawa Valley, starting lighter at first before ramping up closer to the dinner hour.

The mixing line is forecast to gradually sink south and east through the afternoon, allowing areas such as Barrie, Grey Bruce and Belleville to transition over to heavier snow as well.

Meanwhile, across Southwestern Ontario and the Golden Horseshoe, colder air will begin to undercut the departing rain. While much of the steadier precipitation may fall as rain before temperatures drop, any lingering precipitation is expected to change over to wet snow late in the afternoon and early evening.

That changeover timing is not ideal. Even a few hours of steady wet snow during the evening commute can create slick roads, especially as temperatures dip below freezing. Gusty winds approaching 50 to 60 km per hour in some areas may also lead to areas of blowing snow where accumulation occurs, reducing visibility and adding to the travel challenges.

Because this system is moving fairly quickly, the window for the worst conditions will likely be concentrated into just a few hours during the late afternoon and early evening. That is when snowfall rates will be at their peak and when road crews will have the hardest time keeping up. Sudden bursts of heavy snow could overwhelm plows and lead to rapidly deteriorating conditions.

The most intense band is expected to sweep through Eastern Ontario during the late afternoon and early evening, likely reaching the Ottawa Valley between roughly 6 and 8 PM. Snowfall rates approaching or even exceeding 5 cm per hour are possible within this band. Commuters should be prepared for sudden drops in visibility and rapidly accumulating snow on untreated surfaces.

Across Southwestern Ontario and the Greater Toronto Area, snowfall amounts are expected to be much lighter. Most locations in these areas will see rain primarily, followed by a brief period of snow late in the day. While totals are expected to remain under 2 cm in many spots, that small amount combined with falling temperatures could still lead to icy patches Friday evening.

Snow is expected to taper off from west to east through the late evening hours, with most areas seeing precipitation end by around midnight. Some scattered flurries may linger into the overnight hours and into early Saturday morning, but the main storm impacts should be over by then.

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In terms of snowfall totals, Eastern Ontario is expected to see the highest amounts. We are forecasting 10 to 20 cm for communities including Ottawa, Cornwall, Brockville, Smiths Falls, Renfrew, Bancroft, Tweed and Huntsville. Locally higher totals up to 25 cm are possible where the most intense snow bands set up for a few hours.

Amounts are expected to taper off to the south and east, where mixing plays a larger role, and overall precipitation amounts are slightly lower. Locations such as Kingston, Belleville, Peterborough, Orillia, Midland, Tobermory, Bracebridge, Parry Sound, Sundridge, North Bay and Sudbury can generally expect 5 to 10 cm. However, with temperatures hovering near freezing at times, there is a chance some of that snow may partially melt or compact, which could reduce final totals.

Owen Sound, Collingwood and Barrie are forecast to see around 2 to 5 cm. These communities sit very close to the mixing line, so a small shift colder could allow them to overperform and reach closer to 5 to 10 cm in localized areas.

Less than 2 cm is expected across much of Southwestern Ontario and the Greater Toronto Area, with most of that falling after the rain transitions to snow late in the day.

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