Severe Thunderstorm & Isolated Tornado Threat on Tuesday for Southern Ontario

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After experiencing a chilly start to April, Southern Ontario is finally feeling the warmth, bringing a more spring-like atmosphere to the region. This warmth will be especially noticeable on Tuesday as temperatures are expected to climb into the upper teens or even low 20s in some areas.

This warming, combined with an approaching cold front later on Tuesday, will set the stage for the development of thunderstorms.

A potent environment conducive to thunderstorm development is expected to materialize across Southwestern and Central Ontario during the afternoon, fueled by ample daylight heating from the warmer temperatures.


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As the cold front sweeps through the province starting in the late afternoon, a line of storms is anticipated to form, extending from North Bay towards Georgian Bay and into regions east of Lake Huron. According to the latest model data, these storms have the potential to become severe, with all types of severe thunderstorm threats being possible.

A slight severe thunderstorm risk extends from Kitchener through Orangeville and Simcoe County into Central Ontario, with a particular emphasis on the corridor from Orangeville to Bracebridge, where models indicate the most conducive environment for severe storm development. The primary window for these storms is between 3 to 8 PM, varying with the arrival time of the cold front.

These storms could bring large hail, up to the size of quarters or ping pong balls, wind gusts of up to 100 km/h, and the possibility of an isolated tornado cannot be ruled out.


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Areas within the isolated severe risk zone might experience a few storms, but the confidence is lower compared to those within the slight severe zone. As the evening progresses, the risk will evolve into a wind threat as the storms merge into a main squall line, advancing towards the Golden Horseshoe and Eastern Ontario.

In Eastern Ontario, non-severe thunderstorms are anticipated around midnight as the weakening line of storms moves through. Although the severe weather risk is expected to be low by the time the storms arrive, small hail and strong wind gusts are still possibilities.


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For Northeastern Ontario, an isolated severe storm threat is forecasted near the North Bay area as storms develop off Georgian Bay. The severity of the storms is expected to lessen further north, with non-severe thunderstorms predicted for the majority of Northeastern Ontario.


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Rare February Severe Thunderstorm Risk for Parts of Southern Ontario on Tuesday

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As we bid farewell to February, Southern Ontario is set for a wild weather ride, with a rapid-fire succession of seasons in the span of just a few days. This climatic roller coaster is set to take off on Tuesday, bringing an influx of temperatures that are notably higher than what we're used to this time of year. Alongside the warmth, we brace for another hallmark of spring: the threat of thunderstorms.

Looking ahead, we have two distinct thunderstorm risks within a 48-hour window. The early birds in Southern Ontario might be in for a surprise with the first bout of storms expected during Tuesday's morning hours. Coming later in the day, there's the potential for more storm activity that could approach severe levels in the late afternoon and evening.


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As dawn breaks on Tuesday, we expect to see scattered showers and thunderstorms bubble up during the mid to late morning in Southwestern Ontario. Given the environment and minimal energy, these initial storms aren't likely to reach severe thresholds, but they may still pack a punch with lightning, potential for small hail, and strong wind gusts.

These storms will continue to track to the northeast toward Central Ontario and around Georgian Bay, lasting through the morning and into the early afternoon. Throughout the day, a surge of warm air from the southwest will see temperatures soaring into double digits across Southern Ontario.

While everyone across Southern Ontario will feel the heat on Tuesday, the highest temperatures will be found in Deep Southwestern Ontario, affecting locations like Windsor, Chatham, and Sarnia. The extent of this warm spell varies across the different weather models, but don't be shocked if Windsor sees its first 20°C day of the year on Tuesday!


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Progressing into the late afternoon, the escalating heat is likely to stir up atmospheric instability, setting the stage for thunderstorms starting late Tuesday afternoon. These storms are forecasted to pop up to our west, over Michigan and neighbouring states, where a robust environment for severe storms could take shape. However, this forecast remains up in the air, with some of the latest models suggesting storm development could be pushed back to the evening or even overnight which would lead to a lower severe threat.

If storms do materialize, we can't dismiss the possibility of an isolated severe storm tracking into Deep Southwestern Ontario. The primary hazards would be large hailstones, possibly as big as quarters, wind gusts reaching 90 km/h, and heavy downpours. While the tornado risk is not entirely absent, it's expected to remain primarily a concern on the American side of the border.

Another consideration is the lake temperatures this early in the season. While this winter hasn’t been cold by any measure, the lakes are still fairly cold compared to what we would see in the late spring or summer. Colder lakes have a tendency to drain storms of their energy as they cross over the lake and into our region. However, the stretch between Sarnia and Windsor is less shielded by the lakes, leaving it more vulnerable to severe storms crossing the border with little hindrance.

Storms are expected to persist across Southern Ontario into the overnight hours, leading into Wednesday morning. There is a questionable isolated severe risk for the Lake Erie shoreline and into the Niagara region just after midnight that is being picked up by some models.


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Apart from thunderstorms, Tuesday night is shaping up to be unusually mild, rolling into Wednesday morning with temperatures climbing overnight to remain in the double digits for much of Southern Ontario.

But don't be deceived by the unseasonably warm start to your Wednesday. A stark cold front is scheduled to slice through Southern Ontario from the northwest to the southeast beginning late Wednesday morning. This will result in a drastic drop in the temperature from the mid-teens to sub-zero levels in a matter of hours.

The potential for a flash freeze is particularly concerning, especially considering the preceding rain from the storms. Roads are expected to swiftly transition to treacherous sheets of black ice, complicating Wednesday afternoon's commute.

Stay tuned for more comprehensive details on the flash freeze threat, along with an update on the potential for snow as we move into late Wednesday and Thursday.


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Weather Whiplash in Ontario With Record-Breaking Heat, Severe Thunderstorm Risk & Flash Freeze This Week

Get ready for a wild weather ride, Ontario! The old saying will hold true this week: "If you don't like the weather in Ontario, just wait five minutes—it'll change!" And change it will, with a full spectrum of seasons unfurling over the next 48 hours.

As we previously hinted, a ‘heatwave’ is set to roll in for Tuesday and Wednesday, with temperatures climbing into the teens. Parts of Deep Southwestern Ontario are even teasing the 20°C mark, according to some models!


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Thunderstorms are on the agenda for Tuesday, starting with morning storms and a potential severe risk by the afternoon and evening.

Fog, a recurring theme this season, is slated to make a comeback in certain areas on Tuesday and Wednesday. This will be accompanied by heavy rain, dumping 15-30mm by Wednesday morning. For parts of Northern Ontario, we could be looking at significant snowfall totals as the cold air hangs on there. This includes Kenora, Dryden, Kapuskasing, Cochrane and Timmins.

Take a look at Windsor's 10-day forecast—it's a real temperature roller coaster. We're climbing to the first high on Wednesday with temperatures soaring over 15°C, then taking a dive back to near seasonal norms by Thursday.

But hold on tight! We're heading back up for another warm spell this weekend, with the mercury potentially flirting with the 20°C mark by Monday.

For some perspective, the average high for Windsor at this time of year hovers around 3°C. However, the upcoming forecast anticipates highs that will consistently top the seasonal average. And this pattern of temperature swings? It's set to stick around into the early days of March.

Download our free app to view your local forecast.


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But don't pack away your winter gear just yet!

Remember, it's still February, despite what the balmy temperatures might suggest. Winter is gearing up for a comeback by Wednesday morning and afternoon. A sharp cold front will sweep through the province, one of the steepest we've seen in quite some time, with temperatures plummeting from the teens to below freezing in just a few hours.

Given the expected rain and mixed precipitation during this cooldown, we're likely to see road conditions turn treacherous with ice on Wednesday. A tricky commute is on the cards for Wednesday afternoon, and we can't dismiss the potential for school bus cancellations if the flash freeze risk materializes as the models predict.


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From late Wednesday into Thursday, snow squalls are expected to revisit the usual snowbelt regions, with wind chills plunging to near -20°C—a stark contrast to Tuesday's near-record warmth.

And the temperature roller coaster doesn't stop there. As we look towards the weekend and into early next week, another significant warm-up is on the horizon. Because these rapid temperature fluctuations are definitely healthy for our ecosystem! 🫠

We're putting together a detailed forecast, complete with several maps to navigate this complex weather pattern. It's a bit of a task, so bear with us as we compile all the necessary information. Stay tuned!


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Severe Thunderstorm Risk on Tuesday Close to Southwestern Ontario

The Storm Prediction Center (SPC) in the United States has identified a 15% severe risk area in their Day 4 thunderstorm outlook for Tuesday, February 27, 2024.

This 15% severe risk zone is approaching Deep Southwestern Ontario, including Windsor. Currently, it stops just shy of Detroit, but the SPC's trend has been to extend it progressively northeast with each new forecast update.


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The SPC's forecast states, “As thunderstorms develop ahead of the front during the late afternoon and early evening, a severe threat is expected from the Ozarks northward into the southern Great Lakes. Wind-damage, and perhaps a few tornadoes would be possible with supercells and/or the stronger bowing line segments.”

Although it's unlikely for the severe threat to cross the border at this stage, the proximity to Windsor will make it something to watch. The potential for an isolated storm, primarily presenting strong wind gusts as a threat, cannot be entirely dismissed.


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Regardless of the severe threat, we're on the cusp of a welcome warm-up, accompanied by a few non-severe thunderstorms expected between Tuesday and Wednesday.

Stay tuned as we continue to monitor the situation and will provide updates as it evolves.


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Southern Ontario Basks in Unusually Warm Temperatures With a Rare December Thunderstorm Risk on Saturday and Sunday

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Don't be surprised if you hear a few rumbles of thunder or catch a glimpse of lightning later today into Sunday morning.

Southern Ontario is currently experiencing an exceptionally warm weekend for December, with numerous areas reporting double-digit temperatures.

The hottest spots in all of Canada are presently Windsor and St. Catharines, both registering a temperature of 14.5 °C as of 12:50 PM on Saturday. Notably, this might set a temperature record for Windsor, considering the highest recorded temperature on this day is 14.4°C from 1946!


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This warmer weather will lead to some instability later today, with scattered thunderstorms developing this afternoon. While the majority of these storms are expected to be relatively weak and not reach severe levels, the latest data suggests a questionable severe risk around Windsor and Chatham during the mid to late afternoon hours today.

An isolated storm could emerge over Michigan and track into the Windsor area in the next few hours. It's highly unlikely for any storms to become severe today, but we believe it's worth mentioning as it can't be entirely ruled out.

The main risks would be strong wind gusts, small hail, and heavy rainfall. Some parts of Southern Ontario could witness between 10-20mm of rainfall by Sunday morning.

This thunderstorm risk will persist to the northeast, affecting the Golden Horseshoe, Central, and Eastern Ontario later this evening and into the overnight hours.


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You might have heard discussions about a significant storm over the last few days for Southern Ontario. We refrained from discussing it earlier, as models were inconsistent. Some models earlier this week suggested a widespread snowstorm with up to 50cm of snow in some parts of our region! However, that is no longer the case.

The latest model data indicates a potential snowmaker tracking up the US Northeast late Sunday into Monday. It seems that accumulating snow will likely miss Southern Ontario, but it's a close call. There's a possibility of heavier snow along the American border in Eastern Ontario (Brockville, Cornwall, etc.), but even that is uncertain.

Some lake-effect snow activity is also possible early this week around Lake Huron and Georgian Bay. We are monitoring the situation and will provide a comprehensive forecast later this weekend if necessary.


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Thunderstorm Risk Shifts East on Thursday With Severe Storms Possible in Central Ontario & Ottawa Valley

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The recent intense heatwave in Southern Ontario is coming to an end, but not without some thunderstorm activity. This has caused a noticeable cooldown in Southwestern Ontario and around the Golden Horseshoe. As a result, Environment Canada has lifted the heat warning for many regions in Southern Ontario. However, part of Eastern Ontario is still experiencing hot weather and the warning remains in place for them for one more day.

Similar to yesterday, relief from the warm temperatures will come in the form of isolated pop-up thunderstorms throughout the afternoon and early evening hours. The focus of this activity will be from just north of the GTA through Lake Simcoe and up into Central Ontario. Later in the day, the Ottawa Valley could also see some storm activity.

While these storms are expected to remain non-severe for the most part, the environment is favourable for a few isolated storms to reach severe levels. The main risks include 90 km/h wind gusts and hail up to the size of quarters. An isolated tornado can’t be ruled out, but the risk is fairly low. If there is a tornado risk, it will likely be highest around the Lake Simcoe and Bancroft area.

The storm risk is expected to come to an end by later this evening. In the wake of the storms, we will see much cooler air flow in overnight with parts of Central Ontario potentially touching the upper single digits by Friday morning. This will set the stage for a much cooler weekend with weather more usual for this time of the year.

Severe Thunderstorm Risk Returns to Southern Ontario on Wednesday and Thursday

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The first full week of September has begun with unusually warm temperatures, bringing some of the hottest weather we've experienced all summer in Southern Ontario. This hot and humid air is a crucial ingredient in thunderstorms, and it will certainly play a significant role over the next two days, with the risk of severe storms returning to our region later this afternoon and again on Thursday.

As of early Wednesday afternoon, we are currently seeing the development of storms over Michigan, which are tracking into Southwestern Ontario. These storms will continue tracking to the northeast, with more pop-up activity anticipated around Georgian Bay by late afternoon. The daylight heating that fuels these storms will begin to wane in the early evening once the sun sets, leading to a gradual weakening in the storm activity around 8 or 9 PM.

For the most part, these storms should remain non-severe; however, we can't rule out the possibility of a few isolated severe storms. The primary concern will be damaging wind gusts exceeding 90 km/h, and there is also a chance of small hail up to the size of dimes along with heavy rainfall. While the tornado risk for all of Southern Ontario is relatively low, we can never entirely dismiss the possibility of an isolated tornado if the right conditions come together.



It's crucial to note that while we have an expansive isolated severe risk, not all areas within the forecast will experience severe weather. The environment is conducive to severe storms, but pinpointing exactly where these storms will occur remains challenging.

Similar dynamics will be in play on Thursday afternoon and evening. The focus of tomorrow's risk will be in Central and Eastern Ontario, although the development of storms is less certain. The storm mode is expected to be more discrete, increasing the potential for hail and tornadoes compared to today.

There are still many uncertainties, so we are awaiting more data before putting together a forecast for the storms on Thursday. Stay tuned for a detailed forecast, which we will provide either later today or early tomorrow.

ONTARIO: Thunderstorm Forecast for Saturday, September 2, 2023

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Thunderstorms are currently not expected across Southern Ontario on Saturday.

NORTHERN ONTARIO: Thunderstorm Forecast for Saturday, September 2, 2023

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Thunderstorms are currently not expected across Northern Ontario on Saturday.

ONTARIO: Thunderstorm Forecast for Friday, September 1, 2023

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Thunderstorms are currently not expected across Southern Ontario on Friday.

NORTHERN ONTARIO: Thunderstorm Forecast for Friday, September 1, 2023

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Thunderstorms are currently not expected across Northern Ontario on Friday.

ONTARIO: Thunderstorm Forecast for Thursday, August 31, 2023

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Thunderstorms are currently not expected across Southern Ontario on Thursday.

NORTHERN ONTARIO: Thunderstorm Forecast for Thursday, August 31, 2023

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Thunderstorms are currently not expected across Northern Ontario on Thursday.

ONTARIO: Thunderstorm Forecast for Wednesday, August 30, 2023

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Thunderstorms are currently not expected across Southern Ontario on Wednesday.

NORTHERN ONTARIO: Thunderstorm Forecast for Wednesday, August 30, 2023

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Thunderstorms are currently not expected across Northern Ontario on Wednesday.

ONTARIO: Thunderstorm Forecast for Tuesday, August 29, 2023

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Thunderstorms are currently not expected across Southern Ontario on Tuesday.

NORTHERN ONTARIO: Thunderstorm Forecast for Tuesday, August 29, 2023

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Thunderstorms are currently not expected across Northern Ontario on Tuesday.

ONTARIO: Thunderstorm Forecast for Monday, August 28, 2023

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Thunderstorms are currently not expected across Southern Ontario on Monday.

NORTHERN ONTARIO: Thunderstorm Forecast for Monday, August 28, 2023

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Thunderstorms are currently not expected across Northern Ontario on Monday.

ONTARIO: Thunderstorm Forecast for Sunday, August 27, 2023

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Thunderstorms are currently not expected across Southern Ontario on Sunday.