Comparing the Loudest Weather Phenomena: Thunder, Tornadoes, Hail & Ice Quakes

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we did ‘trivia time’ on our social media pages with this question and a huge thank you to all those who participated!

Comparing the Loudest Weather Phenomena

When the weather turns wild, it’s not just the winds and rain that grab our attention, the sound can be deafening! From a crackling thunderclap to the roar of a tornado, certain meteorological events push the boundaries of what our ears can handle. Below, we compare four of the loudest natural phenomena and how their peak volumes stack up.

photo credit: Brandon Morgan

Thunder: Nature’s Cannon

When lightning superheats the air, it produces a shockwave that we hear as thunder. A nearby strike can hit about 120 dB at ground level, about as loud as a rock concert or jet engine. Right near the lightning channel, sound pressure can briefly reach 165–180 dB, and rare “superbolts” may push that volume even higher. Fortunately, these extreme levels are localized; even a very strong strike a mile away typically registers in the 110–120 dB range.

PHOTO CREDIT: GREG JOHNSON TORNADOHUNTER.CA

Tornado: The Freight Train Roar

Survivors often compare a tornado’s roar to a freight train. Typical sound levels near a tornado fall in the 90–100+ dB range, loud enough to make conversation impossible. At very close range, the loudest tornadoes may reach the 120 dB neighbourhood, rivaling a thunderclap or jackhammer. Direct measurements are scarce because no one wants to place microphones in an EF5’s path, but theoretical analyses speculate that peak levels could exceed this. In practice, a violent tornado’s roar can still cause physical pain or hearing damage if you’re near it and especially if it’s destroying trees, buildings, etc.

PHOTO CREDIT: Marcel Strauß

Hail on a Metal Roof: Weather’s Drum Solo

On a calm day, rain on a metal roof is just background noise but hail can turn your home into a drum! Even small hailstones can bump the sound to 80–100 dB in an attic or shed. In extreme cases, especially when large hail combines with hurricane‑force winds, noise levels can rival thunder. A remarkable example is the 1986 Kansas/Missouri derecho, where large hail driven by 100 mph winds created a sustained roar around 120 dB, essentially as loud as a rocket engine. Baseball‑sized hail can still hit the 100+ dB range despite modern roofing and insulation.

PHOTO CREDIT: CHATGPT AI IMAGE OF WHAT A FROST QUAKE MIGHT LOOK LIKE

Ice Quake: Frost’s Explosive Secret

Also known as cryoseisms, ice quakes occur when a sudden deep freeze causes waterlogged ground to fracture. They’re unpredictable and highly localized but witnesses describe the noise as a sharp boom or explosion that can shake a house. Precise decibel measurements are rare, yet anecdotal accounts suggest they can easily exceed 100 dB, on par with a thunderclap. During the January 2014 polar vortex, numerous frost quakes around Toronto woke residents with house‑shaking blasts. While the shaking may be minor, the sound is startling and intense.

Which is the Loudest?!

All four of these weather phenomena can produce sound levels capable of causing hearing damage. Thunder regularly reaches around 120 dB and as mentioned above, superbolts may push this even higher. Tornadoes and massive hailstorms can come close to matching thunder’s intensity, especially at close range. Ice quakes aren’t as well-documented but the explosive nature of frost cracking suggests similar levels. Only extreme events like volcanic eruptions or meteor impacts significantly exceed these volumes. Regardless of the source, any sustained sound above 85 dB can harm your hearing over time.

In summary:

• Thunder: 110‑120 dB from a mile away; near the lightning can reach 165‑180 dB and superbolts may be higher.

• Tornadoes: Typically in the 90‑100+ dB range; violent tornadoes may approach 120 dB.

• Hail on a metal roof: Small hail can be 80‑100 dB; large hail plus ~100 mph winds can roar around 120 dB.

• Ice quakes: Unpredictable frost quakes with booms that witnesses estimate above 100 dB.

And the winner is…

The winner, based on the available data and estimated volumes by experts; thunder from a superbolt lightning strike!

To help confirm our research, we spoke with our friend Dr. Dave Sills, Director of the Northern Tornadoes Project (NTP) and he agrees that the winner is likely a superbolt lightning strike, which has the potential to reach volume levels in excess of 180db. Ouch!

Sources:

STORMY SUNDAY: Parts of Ontario Could Experience Damaging Wind Gusts & Flooding Risk This Weekend

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Environment Canada has released its latest medium range forecast, highlighting the potential for 70-90km/h damaging wind gusts across Southwestern Ontario, the Niagara regions and western GTHA regions on Sunday, October 19th, 2025.

They also mention a rainfall risk for Northeastern Ontario with the potential for 30-60mm of accumulation that could cause isolated flooding.

If this trend continues towards the weekend, it’s certainly possible that the ‘minor’ risk will be increased to a ‘moderate’ risk but seeing as we’re still four days out, it makes sense that Environment Canada is keeping the risk at the minor level.

Environment Canada does have a specific explanation for minor risks and it is: “This weather event is potentially significant or of interest. Users should stay informed.”

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💨 Southern Ontario

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Environment Canada writes in their forecast for Southern Ontario:

“Strong southwesterly winds with gusts of 70 to 90 km/h are likely for areas near Lake Erie and portions of southwestern Ontario. Winds will shift to northwesterly with the passage of a cold front late in the day, with gusts up to 90 km/h possible. Confidence is low regarding the timing and strength of winds expected.”

They also break down the risks:

Hazard(s): Wind

Location: Southwestern Ontario and western portions of the Greater Golden Horseshoe.

Timing: Sunday

Impact(s): Broken tree branches and downed trees. Power outages likely.

Confidence: Low (1 out of 4)

Impact: Moderate (2 out of 4)

🌧️Northeastern Ontario

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Here are Environment Canada’s details for the rainfall risk in Northeastern Ontario:

”Significant rainfall is expected, with rainfall amounts of 30 to 60 mm likely. Confidence is low regarding the exact location of heaviest rainfall at this time.”

They also break down the risks:

Hazard(s): Rain

Location: Portions of northeastern Ontario.

Timing: Sunday

Impact(s): Possible flooding in low-lying areas.

Confidence: Low (1 out of 4)

Impact: Moderate (2 out of 4)

🔎 Staying Safe and Prepared

As we move towards the winter months, it’s critical to stay informed! To keep a close eye on our latest forecasts and get notified of any alerts, download our free app Instant Weather, available on Apple and Android devices.

Take a moment to secure any loose outdoor items before the storms arrive. Things like patio furniture, trampolines, and garbage cans can become projectiles in strong winds.

If you're planning to be on the roads, be prepared for challenging driving conditions such as sudden downpours, significantly reduced visibility, and the possibility of water pooling on roadways, especially in areas expecting heavier rainfall.

Stay safe everyone and if it’s safe to do so, share your reports with half a million community members on our Facebook group called Ontario Storm Reports!

Disclaimer: These forecasts are issued by Environment Canada and typically published via their Twitter/X accounts. We receive these forecast via a daily email and often publish them to help inform our communities.

Autumn’s Grand Finale: Ontario Hits Peak Fall Colours This Thanksgiving Weekend

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If you’re spending the Thanksgiving Weekend in Ontario, you’re in for a treat as the fall colours are now peaking across much of the province! From Central Ontario to the Niagara Escarpment and parts of Southwestern Ontario, this weekend will showcase some of the best fall scenery of the season.

Over the past week, colour change has surged in many areas across Central, Eastern, and Southwestern Ontario, bringing that classic explosion of red, orange, and gold to the forests. For many regions, this weekend marks the perfect time to take a drive, hike, or just relax outdoors surrounded by nature’s best display.

Parks like Forks of the Credit, MacGregor Point, Sauble Falls, The Massasauga, Frontenac, and Murphys Point are all sitting at or near peak colour levels, with coverage between 70 and 90 percent. These areas are glowing with rich maple tones, offering stunning backdrops for family gatherings and Thanksgiving photos.

Check out our new fall colour park dashboard that lets you track the fall colour change for each provincial park!

FALL COLOUR PARK TRACKER

However, farther north, the colours are starting to fade. Northern sections of Central Ontario, including Algonquin, Arrowhead, and Bonnechere has reached their peak several weeks ago, and the recent rain on Friday has accelerated leaf drop in those regions.

In fact, Mikisew Provincial Park has become the first location to officially move out of peak season, with around 80 percent leaf fall now reported. Many of these northern parks are still worth visiting, but visitors can expect more bare branches mixed with patches of remaining colour.

The transition southward is now well underway, with vibrant hues starting to spread into the Golden Horseshoe and Lake Erie shoreline regions. Bronte Creek, Turkey Point, and Point Farms are now showing brilliant orange and yellow tones, while Rondeau and Wheatley continue to progress slowly, likely about one to two weeks away from their peak.

For those in the GTA, Niagara, and Prince Edward County, this weekend should deliver plenty of colour and comfortable weather for outdoor plans.

THANKSGIVING WEEKEND WEATHER FORECAST

The good news is that the Thanksgiving Weekend forecast looks mostly favourable for outdoor activities; however, there will be a few areas of rain to work around.

ESTIMATED TOTAL RAINFALL ON SATURDAY - MAP FROM WEATHERBELL

Saturday will start off on a cloudy and damp note for many, especially across Central Ontario and portions of the GTA. Some scattered precipitation is expected during the morning and early afternoon hours, with the chance for locally heavier pockets of rain near the northern shores of Lake Ontario, between Toronto and Cobourg. Rainfall amounts could reach 10 to 15 mm in those localized zones.

Don’t let that discourage your plans, though, as the rain will be scattered and not persistent, and most areas should begin to dry out later in the day. By Saturday afternoon and evening, conditions will improve across Southern Ontario, while some lingering showers may persist just north of Lake Ontario.

Sunday looks to be the best day of the long weekend. Forecast models show mostly dry and mild weather, perfect for any outdoor Thanksgiving plans or fall colour tours. A few isolated showers could develop in Niagara or Far Eastern Ontario, but these should be brief and light.

ESTIMATED AIR TEMPERATURE on SATURDAY - MAP FROM WEATHERBELL

After a cool and damp Friday, temperatures on Saturday will hover right around seasonal values, with daytime highs in the low to mid-teens. Which is about what you’d expect for early to mid-October. It’ll feel crisp, but not unpleasant, especially once the rain clears.

ESTIMATED AIR TEMPERATURE on sunday - MAP FROM WEATHERBELL

On Sunday, slightly warmer air returns. Temperatures will rise into the upper teens, with some areas possibly touching 20°C or a bit higher in parts of Southwestern Ontario. It’ll be a comfortable, mild day overall, great for hiking, apple picking, or those traditional family dinners outside if you’re lucky enough to have a sunny patio.

Monday, Thanksgiving Day itself, should feature similar conditions to Sunday with a mix of sun and clouds, and daytime highs again in the upper teens or low twenties.

FINAL THOUGHTS

This Thanksgiving Weekend will likely offer one of the most colourful backdrops in recent memory across much of Southern Ontario. With so many regions now at or near their fall colour peak, and comfortable weather expected through much of the weekend, it’s the perfect time to get outdoors and soak in the season.

If you’re heading north, expect a more subdued scene with leaves already past peak. But if you’re staying closer to home in the GTA, Niagara, or Southwestern Ontario, you’re right on time to experience the full brilliance of Ontario’s fall foliage.

Grab your camera, take a drive down a country road, or plan a hike through one of Ontario’s provincial parks. The combination of crisp air, golden forests, and warm afternoon sun makes this Thanksgiving one to remember.

Enjoy the beauty, and Happy Thanksgiving from all of us at Instant Weather!

Developing Snowstorm Sets its Sights on Parts of Saskatchewan and Manitoba

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A moisture-loaded system coming up from the south late this weekend will collide with a cold front dropping in from the north. This setup is expected to bring the first true taste of winter to parts of Saskatchewan and Manitoba.

Rain will arrive first on Sunday as warmer air briefly moves in. As the cold front pushes through, temperatures will begin to fall and pockets of wet snow are expected to start forming in central Saskatchewan by late Sunday morning. Through the afternoon and evening, this snow will spread eastward and become more widespread.

The ground is still relatively warm for mid-October, so the first flakes will likely melt on contact. Once snowfall rates increase, the snow will start to stick, especially on grassy areas, vehicles, decks, and untreated road surfaces. Since the system begins as rain and may end as rain in some areas, exact snowfall totals are tricky to pinpoint. Even so, some parts of Saskatchewan could see as much as 10 cm by Sunday night where the snow is heavier and more consistent.

Northern Manitoba has a better chance at seeing more impactful snowfall. Snow is expected to move in Sunday evening and continue through Monday afternoon. In the higher-impact zone shown on the forecast map, up to 20 cm of wet, accumulating snow is possible if temperatures stay cold enough. Areas just outside the main zone may still see flakes mixing in with rain, especially overnight when temperatures briefly drop near or just below freezing.

euro model data showing significant wind gust potential in central Manitoba

Winds will also be a big part of this system. Gusts will begin increasing Sunday afternoon and peak overnight. The Euro model is showing extreme gust potential over 150 km/h in one of its runs, which is likely overdone. However, gusts in the 90 to 100 km/h range are possible and much more realistic, especially across Southern and Eastern Manitoba. These strong winds, combined with wet snow or heavy rain could lead to poor visibility, messy travel and slushy, wind-driven road conditions.

This is a classic early-season system where small temperature changes will make a big difference. Some areas may just see cold rain, while others could see a surprising amount of wet snow in a short time. Conditions may change quickly through Sunday and Monday, with a true November-like feel even though it is only mid-October.

We will continue to update this forecast as new data comes in and the system approaches!

Get Your Shovels Ready: Ontario's Snowbelt Could Be Buried Again This Winter

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Satellite image from GOES-16 shows lake effect snow coming off the Great Lakes on February 29th, 2024. Courtesy of CSU/CIRA & NOAA.

The summer of 2025 was a hot one in Southern Ontario, in which we saw high temperature records consistently broken throughout the region. This trend has continued into October, with temperatures surpassing 30°C in parts of Southwestern and Eastern Ontario during the first weekend of the month.

Despite the fact that we’re gradually moving into the coldest part of the year, the heat from the summer and fall will continue to impact local weather conditions this winter. This will be particularly evident as lake effect snow, a phenomenon that occurs every year in the late fall and early winter in Southern Ontario.

The two main ingredients necessary for the development of lake effect snow are a large unfrozen body of water and a very cold air mass. The air mass needs to be at least 13°C colder at the 850mb pressure level of the atmosphere (this is typically found at around 1500 metres) than the temperature of the surface of the water. Once this threshold is reached, it’s like a switch being flipped and the lake effect snow machine starts.

There is more to the development of lake effect snow than just cold air and an open body of water. Another key component in lake effect snow development is moisture. Ideally, the relative humidity at the surface needs to be at least 80% for lake effect snow to form and levels below 70% could actually inhibit development. It can usually be assumed that the lake itself can provide enough moisture, but this is not always true. There also needs to be limited wind shear with height between the surface and the 700mb pressure level so that the moisture is more focused, sort of like a hose. The strongest, most organized bands of lake effect snow develop when the wind shear is less than 30°.

Finally is the concept known as “fetch”, which is the distance that the air mass travels over the lake. Fetch needs to be at least 100km in order for lake effect snow to develop and the greater the fetch, the more snow is produced. When considering prevailing wind directions, the traditional snowbelts are found in areas that are downwind of the greatest possible fetch over the Great Lakes, i.e. Buffalo and the entire length of Lake Erie.

The creation of lake Effect Snow. Courtesy of Environment Canada.

As the cold air mass travels over the much warmer surface of the lake, the warmth and moisture from the surface is transferred into the lower atmosphere. The warmer, moister air rises and it eventually cools and condenses, forming narrow bands of clouds. These clouds continue to travel over the open lake, gathering even more moisture, until they eventually reach land and the snow starts to fall at rates that can easily exceed 5cm per hour and could even be as high as 20cm per hour! It’s important to note that the hardest hit areas are actually not found immediately at the shoreline, but rather 30-50km inland from the lake.

The direction of the winds dictates which areas are hit by the lake effect snow so as long as the ideal conditions continue, so too will the development and subsequent falling of lake effect snow. This could lead to several days of heavy snow hitting the same area while there are sunny skies less than 20km away. A slight shift in wind direction can quickly change which area gets hit and that makes lake effect snow notoriously tough to forecast. In Southern Ontario, lake effect snow typically hits areas to the east of Lake Huron and Georgian Bay, but it can also impact communities to the north of both Lake Erie and Lake Ontario.

Surface Temperature of Lake Huron throughout 2025 plotted with the 30 year average. Courtesy of NOAA CoastWatch.

So how does a hotter-than-average summer impact lake effect snow? To put it simply, a warmer summer leads to warmer lakes. Looking at Lake Huron, the main source of lake effect snow in Southern Ontario, the surface water temperature is approximately 2°C warmer than the 30 year average.

One of the important properties of water is its high heat capacity, which means that lakes heat and cool slower than the surrounding land. The warmer lakes will take longer to freeze, meaning that the lake effect snow machine can run even longer.

The current surface temperatures across the Great Lakes are very similar to last year at the same time. Many will remember last fall when the Muskoka Region was buried after several days of intense lake effect snow, trapping people in their homes and cars after the highways were closed.

This trend continued through most of the winter due to large expanses of open water remaining present in the Lakes. This was particularly the case in Bruce, Grey, and Huron Counties, where consistent lake effect snow resulted in massive snow piles and drifts that were up to 12 feet tall! The amount of snow also had an effect on local schools, with more than 30 snow days announced for students of some school boards.

Surface temperatures of the Great Lakes as of October 7th, 2025. Courtesy of Noaa Coastwatch.

Surface temperatures of the Great Lakes as of October 6th, 2024. Courtesy of NOAA Coastwatch.

While it is still too early to predict exactly how much snow will fall and where over the coming months, it is looking likely that we can expect a considerable amount of lake effect snow like last year.

Fall Colours Reaching Their Peak Just in Time for Thanksgiving Weekend for Much of Southern Ontario

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It’s shaping up to be a picture-perfect Thanksgiving Weekend across Ontario, and nature is putting on one last spectacular show before winter sets in. Across much of the province, the fall colours are now reaching their peak, just in time for the long weekend and this year’s display is one you won’t want to miss.

If you’ve been waiting for the ideal time to hit the road for a scenic fall drive, this is it. Central and Eastern Ontario are bursting with colour right now, with brilliant reds, oranges and yellows covering the forests from Muskoka to the Ottawa Valley.

Check out our new fall colour park dashboard that lets you track the fall colour change for each provincial park!

FALL COLOUR PARK TRACKER

Parks such as Algonquin, Arrowhead, Bonnechere, The Massasauga, Silent Lake, and Bon Echo are all reporting colour change at or above 70 percent. The rich mix of maples and birches is producing a stunning contrast that paints the landscape with fiery autumn tones. For many areas, this is the absolute peak which is that magical window when most trees are fully changed but still hold plenty of leaves.

However, that window is short-lived. Some parks are now reporting more than 50 percent leaf fall, meaning these vibrant views won’t last much longer. If you’re planning a trip to Algonquin or other northern parks, this weekend could be your last chance to experience the full canopy before winds and cooler nights strip the trees bare.

Even with the ongoing leaf fall, the colour coverage across Central and Eastern Ontario remains exceptional. Parks including Frontenac, Voyageur, and Mikisew are glowing with late-season golds and deep reds, offering some of the best hiking conditions of the year. Clear skies and mild temperatures will make it easy to spend the whole day exploring the great outdoors.

While the north is beginning its gradual slide past peak, Southern Ontario is just getting started. From the Niagara Escarpment to the Lake Huron shoreline, and stretching east through Prince Edward County and the GTA, colour change is advancing quickly. Many of these regions are now sitting between 40 and 60 percent colour change, which means peak fall colour conditions are expected to line up perfectly with Thanksgiving Weekend.

That’s welcome news for anyone planning outdoor gatherings or day trips over the long weekend. Whether it’s a drive through the Dundas Valley, a picnic at Forks of the Credit, or a stroll through Rondeau or Bronte Creek, the next few days should feature stunning scenery and warm sunshine.

ESTIMATED AIR TEMPERATURE on sunday - MAP FROM WEATHERBELL

The latest high-resolution model data even suggests we’re in for another burst of summer-like warmth across Southern Ontario. On Sunday, temperatures are forecast to climb into the mid to upper twenties, with some inland areas possibly reaching the 30°C mark.

It’s a rare treat for early October and more like something out of August than Thanksgiving Weekend. For those closer to the lakeshores, expect slightly cooler highs in the lower twenties thanks to the lake breeze. Still, it’ll be a gorgeous day for a fall road trip, with plenty of sunshine and mild winds making for ideal driving conditions.

The warm weather will also help extend the life of the remaining leaves, giving the region a few extra days of brilliant colour before cooler air and rain return later next week. So if you’ve been putting off that annual fall colour tour, now’s your moment.

For the best viewing experience this weekend, head toward higher elevations in Central and Eastern Ontario, where the mix of tree species and cooler nights has created the most vibrant hues. Algonquin Provincial Park remains the top spot for photographers and nature lovers alike, with Arrowhead, Bonnechere, and Silent Lake close behind.

Those staying closer to home in Southern Ontario will still be rewarded with spectacular views. The rolling hills around Caledon, Mono Cliffs, and Hockley Valley are quickly transforming into a patchwork of gold and crimson. In Niagara, the escarpment trails and vineyards are beginning to glow, creating a perfect backdrop for Thanksgiving festivities.

Don’t forget about Prince Edward County, where fall colours are blending beautifully with the region’s scenic farmland and wineries. Areas like Sandbanks and Presqu’ile are starting to see that golden shift as maples and oaks catch up to their northern cousins.

As always, timing is everything when it comes to fall colour chasing. While many areas will look their best this weekend, winds or rain later in the week could quickly thin out the foliage. Keep an eye on local forecasts if you’re planning to travel, and be ready to head out early in the morning for the best light and least crowded parks.

So charge up your camera, roll down the windows, and take in every view, because before long, those vibrant trees will trade their fiery tones for the bare branches of late fall. Enjoy the show while it lasts, and have a wonderful Thanksgiving Weekend surrounded by the best of Ontario’s autumn beauty.

GROUNDBREAKING: AI Satellite Tool Detects Five New Tornadoes in Ontario

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Before-and-after satellite images with the tornado’s damage path highlighted in red

The Northern Tornadoes Project (NTP) out of Western University has a clear mission: detect every tornado across Canada. However, due to Canada’s enormous size and extensive forest cover, tornado damage often happens in remote areas far from communities, where it may go unreported.

To find these undocumented tornadoes, researchers previously conducted endless hours of manual reviews of high‑resolution satellite images. In 2024, they combed through over 3.2 million km² of forested land, an effort that took roughly 300 person-hours. At present, NTP researchers need several months to finish this work as visual fatigue sets in after just 3-4 hours of scanning.

To accelerate the search, NTP researcher Daniel Butt, a PhD candidate in software engineering, developed an AI assisted satellite review tool. The system compares pairs of satellite images taken one year apart (Planet Labs August imagery) and uses machine learning to flag areas where trees have been damaged in a way consistent with tornadoes or downbursts.

Diagram of a convolutional neural network model used to predict patches of tree damage.

First batch of Tornadoes:

A bit of history: these five newly confirmed NTP tornadoes mark the first cases identified using AI-assisted satellite scans of tree damage in forested regions. The tool was first tested in Northern Ontario, east of Lake Superior, where its findings were then manually confirmed and documented. Four of the tornadoes (one rated EF2) occurred on July 28, 2025, and the fifth on August 16, 2025.

Event summaries, a regional map, and satellite imagery highlighting the detected tree damage are included below.

Date: July 28, 2025 – 1:25 AM
Location: Whitefish Lake, ON (south of White River)
Rating: EF2
Details: Winds near 190 km/h. Track about 9.5 km long and up to 670 m wide.

Date: July 28, 2025 – 1:35 AM
Location: McMaster Lake, ON (south of White River)
Rating: EF1
Details: Winds up to 145 km/h. Track about 4.8 km long and 510 m wide.

Date: July 28, 2025 – 3:45 AM
Location: Hellyer Lake, ON (northeast of Chapleau)
Rating: EF1
Details: Winds up to 145 km/h. Track about 7.2 km long and 350 m wide. Same storm also spawned the Oscar Lake tornado.

Date: July 28, 2025 – 3:55 AM
Location: Ridley Lake, ON (northeast of Chapleau)
Rating: EF1
Details: Winds near 145 km/h. Track about 4 km long and 250 m wide.

Date: August 16, 2025 – 8:50 PM
Location: Abbott Lake, ON (northwest of Sudbury)
Rating: EF1
Details: Winds near 145 km/h. Track about 5 km long and 350 m wide.

A regional map highlighting the five newly confirmed tornado locations identified using AI-assisted satellite review.

Key steps in the process include:

- Acquiring images: Obtain two sets of late‑summer satellite images over the same area, one year apart, from Planet Labs.

- Filter out noise: Use Government of Canada land‑cover maps to exclude non‑forested zones and Planet Labs’ cloud-masks to remove clouds from the imagery.

- Compare the difference: Analyze the red band of the “before” and “after” images to highlight where vegetation has changed.

- Run the model: Feed 32 × 32 pixel patches into a convolutional neural network trained to recognize tornado or downburst damage.

- Review flagged areas: Only review areas with a high probability of damage, dramatically reducing the time needed for manual scanning.

Before-and-after satellite images (Planet Labs, 4.7 m) of the Lac Pedro tornado. The “difference” image highlights changes caused by the storm, and the AI prediction shows areas where tree damage is most likely.

Early tests of this proof‑of‑concept tool have already revealed many potential tornado tracks across Canada that were missed by manual searches. NTP scientists are now verifying these candidates in the field and refining the model to reduce false alarms.

Screenshot of the satellite search software. Red highlighted areas show where the model detected significant tree damage with high confidence.

This AI assisted approach promises to help NTP achieve its goal of mapping every tornado, even those hidden in Canada’s vast forests. By automating much of the search, researchers can focus their efforts on the most promising locations and respond to severe weather reports more quickly.

Severe Thunderstorms Possible for Manitoba Thursday, But Risk Remains Questionable

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The southern half of Manitoba, particularly in the southeast, could see some severe thunderstorms today when a cold front tracks through the region. However, in typical Manitoba fashion, whether storms end up even developing today is very questionable.

The cold front will begin to move through Southern Manitoba early this afternoon and it should reach the Winnipeg area around the late afternoon or early evening hours. Normally, a cold front is more than enough to trigger severe thunderstorms, but the issue is that there is expected to be a significant amount of capping in the atmosphere today, which would greatly inhibit thunderstorm development.

Due to this capping, there is considerable disagreement between weather models regarding when and where thunderstorms could end up forming today. There are those that show storms initiating in Southern Manitoba beginning in the late afternoon, while other models have storm development beginning much later, once the cold front has crossed into Northern Ontario. To cover this range in possibilities, our forecast has a Slight risk from the Red River Valley to the Ontario border.

The hrdps model showing thunderstorms to the south and east of lake Winnipeg at 6pm CT, courtesy of WeatherBell.

If storms end up developing in Manitoba later today, they will likely start off as isolated supercell thunderstorms along the front that should then quickly merge into a line of storms that continues tracking eastward. These could end up being quite strong storms, especially since the same cold front triggered strong severe thunderstorms in Central Saskatchewan yesterday which produced some very damaging winds, large hail, and even a few tornado warnings.

The risks in Manitoba today are much the same if the storms end up developing here: very strong wind gusts that could be well in excess of 100km/h, hail up to the size of tennis balls, and torrential downpours that could lead to localized flooding. There is also the possibility of an isolated tornado, especially closer to the Ontario border.

We will be keeping an eye on how the situation unfolds today and if storms end up forming within the province later today, we will provide updates and probably livestream.

Strong Severe Thunderstorms with Tornado Threat Possible in Central Alberta and Saskatchewan Throughout the Day & Overnight

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There is a widespread chance for thunderstorms across Alberta and Saskatchewan today, with particularly strong storms also possible in parts of both provinces. A low pressure system has been developing in the Foothills this morning and is expected to track eastward into Saskatchewan by the mid to late afternoon. The warm and cold fronts associated with this low will be the trigger behind today’s thunderstorm development.

We’ve already begun to see some weak storms moving through parts of Central Alberta and additional isolated thunderstorms should begin to develop in the early to mid afternoon through the Foothills around Calgary and southward. Together, these storms are expected cross Alberta and into Saskatchewan through the remainder of the afternoon and evening. The thunderstorms are then anticipated to continue crossing Central Saskatchewan through the evening and into the overnight hours, before they finally begin to taper off.

Despite the storms expected to be isolated throughout the day, the risk is widespread because it has been difficult to pin down exactly where the storms will impact. There is also the possibility of some capping, which could limit thunderstorm development from even occurring.

Today’s storms, if and when they develop, could easily strengthen to become strong supercell thunderstorms, which could have the potential to produce damaging winds in excess of 100km/h, hail as large as golf balls, and heavy downpours that may lead to localized flooding. The risk of these storms stretches from Calgary to Wynard, SK, however, we have highlighted an area where the strongest of today’s storms could possible hit.

This area covers parts of East Central Alberta and West Central Saskatchewan, from Wainwright, AB to Warman, SK and including Saskatoon, and is the bullseye for the greatest severe weather threat this afternoon and evening. Severe thunderstorms that impact this region could possibly produce destructive wind gusts well in excess of 100km/h, as well as hail that could be as large as tennis balls and even heavier rain with an increased chance of flooding. This area could also end up seeing a tornado or two touch down.

We will be keeping a close eye on the situation throughout the day and we will likely be livestreaming later, once the thunderstorms have developed and strengthened.

Widespread Severe Thunderstorm Threat Across the Prairies Friday into Saturday, Tornado Risk in All Three Provinces

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The same system that brought some severe thunderstorms to Central and Northern Alberta yesterday, albeit much weaker than originally anticipated, could once again trigger severe thunderstorms today. This time, however, we’re looking at two distinct areas across the Prairies where severe thunderstorms could impact.

The first area of concern is across the southern half of Manitoba and in Eastern Saskatchewan, along the provincial border.

Isolated thunderstorms could start to develop along Saskatchewan-Manitoba border, especially in the area from Hudson Bay to Cumberland House, around the lunch hour. These storms should then track eastward into Manitoba fairly quickly and they could become severe while still in Saskatchewan. If the storms remain sub-severe as the enter Manitoba, it’s very likely that they will still strengthen to become severe as they continue eastward throughout the afternoon and evening.

Additional thunderstorm development could continue southwestward, back into Southeast Saskatchewan, throughout the afternoon. These storms are also expected to track eastward across Manitoba through the evening and overnight, leading to the widespread severe risk.

It’s worth noting that thunderstorm development throughout this entire area is slightly questionable. The environment will be primed with heat, moisture and instability, but there’s the possibility that capping in the atmosphere will prevent them from even forming in the first place. If this cap breaks, however, we could be looking at some explosive thunderstorm development.

Any storms that do develop will likely have the potential to produce golf ball-sized hail or larger, damaging wind wind gusts in excess of 100km/h, and heavy downpours that could lead to some localized flooding. There is also the risk of a tornado forming from storms that could move through Southwestern Manitoba and into the Interlake and Red River Valley in the evening. It’s possible that the tornado risk could extend into Winnipeg, but there is some uncertainty with how far east it goes.

Simulated radar from the HRRR model shows the possible location of storms at 5pm CT, courtesy of Weather Bell.

Meanwhile, there will also be the risk for severe thunderstorms to form in Southern Alberta, along the cold front that continues to push southward through the province.

Scattered thunderstorms could start to develop as early as the mid afternoon throughout the Foothills, mostly to the south of Red Deer. While some of the storms that could develop may become severe, those that develop from Airdrie to Claresholm will be the ones worth watching today.

It’s not until a bit later in the afternoon and into the evening that this area could see the development of thunderstorms. These particular storms will likely strengthen quickly into strong, long-track supercell thunderstorms that will travel eastward across Southern Alberta through the evening. It’s entirely possible that these supercell thunderstorms could maintain their strength through the evening and overnight as they push deep into Saskatchewan, possibly reaching as far east as Moose Jaw, and maybe even into Regina, in the early morning hours.

The threat from the severe storms in Alberta and into Saskatchewan today is very similar to yesterday, with the potential for golf ball-sized hail, damaging wind gusts in excess of 100km/h, heavy downpours that could lead to localized flooding, and even the possibility of a tornado. However, considering that yesterday’s High Risk from Environment Canada and expectations from weather models didn’t quite materialize, we’ve opted to go with a Slight Risk for Southern Alberta and Saskatchewan today. However, the possibility is still there for strong storms to develop so be mindful of any Watches or Warnings that may be issued.

Strong Severe Thunderstorms with Tornado Threat Possible in Central Alberta, Widespread Severe Risk Throughout Northern Alberta and into Saskatchewan

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Now that a warm front has brought some heat back into Alberta, active weather returns. Severe thunderstorms are possible across Northern and Central Alberta this afternoon, and into Saskatchewan later this evening. Central Alberta, in particular, could see some especially strong storms today, complete with the risk of an isolated tornado.

There have already been some scatted showers in Northern Alberta this morning, mostly in the northwest. Further development of thunderstorms is likely across the region and into Northern Saskatchewan this afternoon. These storms are expected to continue through the evening and into the early overnight hours before tapering off. It’s possible that some of these scattered storms could become severe throughout the day, with the potential for strong wind gusts up to 100km/h, toonie-sized hail, and heavy downpours.

The main area of concern for today, however, is in Central Alberta. Thunderstorms are expected to initiate in this region in the early to mid afternoon, which will gradually track eastward through the remainder of the afternoon and into the evening and overnight.

These storms likely strengthen into strong supercell thunderstorms by the late afternoon, which brings a strong risk to an area from Olds to Drayton Valley and east towards Wainright. There is the threat of hail larger than golf balls, damaging wind gusts in excess of 100km/h, heavy rain, and even the risk of an isolated tornado. These storms could be a major issue for motorists, especially between Red Deer and Edmonton, as they are expected to cross the QE2 during the evening commute.

The severe weather threat should decrease during the late evening and overnight hours, with the storms weakening as they continue along an eastward trajectory towards Saskatchewan. There is still the chance, however, that an isolated storm could remain severe during this time frame, which could still have the potential to produce large hail and strong wind gusts. The tornado risk, however, will decrease greatly.

⛈️ Strong Severe Thunderstorm & Tornado Risk For Ontario on Thursday Evening

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The summertime heat we’ve been experiencing is about to fuel some potentially strong thunderstorms in Ontario on Thursday, July 24, 2025. The main risk is in the evening and overnight hours but some areas could see strong storms in the afternoon as well, especially in Northeastern Ontario.

Some of these storms, particularly from the Bruce Peninsula and east towards Muskoka, Algonquin and potentially through parts of eastern Ontario may see a strong damaging wind storm (MCS), which is showing up on several high-resolution models. The timing looks to be late afternoon into the evening and overnight as it moves east towards Quebec.

Across other parts of Ontario, there is a risk for a cluster or line of storms from as far south as Essex County, all the way up to northeastern Ontario in the late afternoon into the overnight hours. Some models suggest it could arrive in the late afternoon but quite a few are suggesting the storms won’t arrive for most of us until the evening or overnight, especially in the east.

Damaging wind gusts, potentially exceeding 100km/h+, large hail, torrential rainfall with isolated flooding and frequent lightning are the main risks. We’re also seeing the potential for a few isolated tornadoes with this system, especially in orange (3) zone on the forecast map.

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In the image above, Environment Canada has issued their forecast for Thursday, highlighting all of the southwestern, central, golden horseshoe and eastern Ontario regions in a 2/4 “Moderate weather threat”.

Below is a regional breakdown based on Environment Canada’s forecast details:

📍 Location A: Portions of Southern & Northeastern Ontario

Hazards: 🌬️ Wind, 🌨️ Hail, 🌧️ Rain, 🌪️ Tornado, ⛈️ Thunderstorms
Timing: Afternoon and evening

Impacts:

  • 🪁 Loose objects may be tossed

  • 🏚️ Damage to weak buildings

  • 🌳 Broken tree branches and downed trees

  • 🌿 Possible damage to plants and crops

  • 🌊 Flash flooding and pooling on roads

  • ⚡ Power outages likely

Rainfall: Up to 50 mm

Confidence: Moderate
Impact: Moderate

Details:
Storms may bring wind gusts up to 100 km/h, rainfall up to 50 mm, hail up to 2 cm, and the potential for isolated tornadoes. Activity begins in the northwest and tracks southeastward through the day.

📍 Location B: Portions of Southwestern & Eastern Ontario + Greater Golden Horseshoe

Hazards: 🌬️ Wind, 🌧️ Rain, ⛈️ Thunderstorms
Timing: Late afternoon and evening

Impacts:

  • 🌳 Broken tree branches and downed trees

  • 🌊 Flash flooding and pooling on roads

  • ⚡ Possible power outages

Rainfall: Up to 50 mm

Confidence: Moderate
Impact: Moderate

Details:
Scattered thunderstorms may produce wind gusts up to 90 km/h and locally heavy rainfall.

More details ASAP about this storm risk. Stay safe on Thursday, folks!

And a big thanks to the sponsor of this forecast; Kempenfest in Barrie! For those who don’t know, our own Adam Skinner will be performing at Kempenfest this year with his new rock band ‘Face The Lion’! They’ll be opening for the one and only Colin James on Saturday, August 2nd!

Here’s some more details on Kempenfest:

”Kempenfest presented by TD, is Barrie Ontario’s signature festival event, celebrating 53 years Aug 1-4, 2025, located across two-kilometres of Barrie’s beautiful waterfront. The annual event is one of Ontario’s largest waterfront festivals, featuring 300 arts & crafts vendors, a midway, community village, antiques, face painters, buskers, great food, a poutine village, and two stages of live music! Evening concert headliners include Shawn Desman, Colin James, The Washboard Union, and The Practically Hip, with many more!”

We hope to see you there!

Severe Storms Possible in Alberta & Saskatchewan Saturday with Tornado and Funnel Cloud Risk

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The cluster of severe thunderstorms that crossed through Alberta yesterday evening and overnight has been weakening as they have continued to track through Southern and Central Saskatchewan this morning. On the backside of these storms, there should be sufficient clearing in order for more severe thunderstorms to develop throughout Central and Southern Alberta and into Southwestern Saskatchewan.

Thunderstorm development should begin in the early to mid-afternoon, with scattered storms in Southern Alberta and into Southwestern Saskatchewan. The majority of these storms in Alberta will possibly become severe, but they aren’t expected to be too strong as they track eastward throughout the afternoon. These storms could bring some strong gusts, small hail, and heavy rain to areas in their path today.

Storms that could form to the north of Medicine Hat, however, and into Saskatchewan are expected to be the stronger, with the possibility to produce damaging wind gusts up to 100km/h and hail as large as Timbits, along with heavy downpours.

The possibility of strong storms developing to the west of Swift Current early this afternoon is worth noting. These particular storms could strengthen into a severe line that extends southward to the US border through the afternoon.

There is also the risk of a tornado or two forming during the early hours of these storms’ lives, in the late afternoon and the early evening, in an area that includes Shaunavon, Swift Current, Assiniboia and just into Moose Jaw. This risk does diminish as the line pushes eastward, with the storms expected to bring a strong wind and hail threat into Regina and to the east throughout the evening hours.

Overall, the intensity of storms will be dependent on how much daytime heating can occur and how much moisture can be funnelled northward following this morning’s active weather.

The dashed line outlines the funnel cloud risk from environment Canada

Back in Alberta, more storms could kick off in the Foothills a bit later in the afternoon. These storms will likely be more organized than the scattered pop-up storms expected earlier in the afternoon. There is a chance of them becoming severe in the evening as they track eastward through Calgary and areas to the south, with the possibility of producing strong wind gusts, toonie-sized hail, and heavy rain which could result in more localized flooding.

There is also the possibility that funnel clouds could develop today southeast of Edmonton, from Camrose to Oyen. It’s important to remember that funnel clouds have the potential to touch down as weak landspout tornadoes so be alert if you’re in this area today.

Widespread Severe Thunderstorm Risk Throughout Central & Southern Alberta, Threat of a Tornado South of Calgary

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A widespread risk of severe thunderstorms is in place for today across Central and Southern Alberta, with the threat of a tornado in parts of Southern Alberta.

Thunderstorm activity will kick off in the early to mid-afternoon through a large stretch of the Foothills, particularly in Central Alberta. These will be slow-moving storms that are expected to develop from the Calgary area to Grande Prairie and could have the potential to bring golf ball-sized hail and strong wind gusts to the region. These storms are also expected to have plenty of precipitation associated with them, which could result in some localized flooding before the storms taper off in the late evening.

There is the chance for storms to also pop up around Calgary and to the south at the same time, but these storms should be slightly weaker and could be short-lived. This will then be followed by some weak storms that will cross into the area from British Columbia in the late afternoon and early evening.

Storms in this second wave are expected to rapidly intensify into supercell thunderstorms as they track east of the Rockies, with the potential to hit the area with damaging wind gusts in excess of 100km/h and hail larger than golf balls. There is also the risk of a tornado or two developing to the south and southeast of Calgary, in an area that includes High River, Claresholm, Lethbridge, and Taber.

The storms in Southern Alberta will track much further east than those expected in Central Alberta earlier in the day. They will likely continue moving eastward towards Saskatchewan overnight, but are expected to lose some intensity during that time period.

Severe Thunderstorms Possible in Southern Alberta & Southwestern Saskatchewan Thursday, Along with Risk of Funnel Clouds

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Despite some cooler temperatures still sticking around, severe thunderstorms are likely today in Southern Alberta and into Southwestern Saskatchewan.

Thunderstorms have already been making their way through parts of Southern Alberta this morning and for the most part, they’ve been fairly weak. As we progress into the afternoon, some of these storms could strengthen to severe levels as they continue tracking east-southeastward. Additional thunderstorm development is also expected to occur closer to the US border through the afternoon, which will also probably become severe. The thunderstorms will track into Southwestern Saskatchewan later in the afternoon and will continue until the late evening hours, at which time they will move south of the border.

The area with the greatest risk of severe weather today will be in deep Southeastern Alberta and Southwestern Saskatchewan, as shown in yellow on the forecast map. In this region, storms could produce strong wind gusts and Timbit-sized hail. These threats also also possible throughout the rest of Southern Alberta and Southwestern Saskatchewan, shown in green, but the risk is slightly lower.

The dashed line outlines the funnel cloud risk from environment Canada

There is also the chance for funnel clouds to form today to the north of where the severe thunderstorms are expected. This will be in the area from Calgary and Olds, eastward through Drumheller and Hanna, and just crossing into Saskatchewan to include the Leader area. If you’re in this region, it’s important to remember that funnel clouds can possibly touch down as weak landspout tornadoes.

Ottawa Area, Eastern Ontario in Bullseye for Thursday’s Widespread Severe Storm & Tornado Risk; Isolated AM Risk for Southwestern Ontario & GTHA

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The oppressive heat that has been locked across Southern Ontario the past week is on the way out. But first that relief will come in the form of a cold front that is likely to clash with the hot air to create some strong thunderstorms ahead of the front.

Some of these storms, particularly in Eastern Ontario during the afternoon on Thursday could reach severe levels with strong wind gusts being the main threat. One or two tornadoes are also possible with the strongest environment being along a corridor from Tweed to Ottawa.

With the cold front already on our doorstep as of early Thursday morning, it is expected to gradually slide across Southwestern Ontario and the Golden Horseshoe through the overnight and pre-dawn hours on Thursday.

While this isn’t ideal timing for storm development, we can’t rule out some nocturnal development. And if these developments occur, the environment could certainly support a few marginally severe storms primarily with strong wind gusts and heavy rainfall.

The tornado risk isn’t zero, but it’s also not particularly strong due to the timing of the overnight storms. But the environment could support a brief spin-up through Southwestern Ontario into the GTA, but it’s very questionable.

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For Deep Southwestern Ontario, we are looking at the bulk of the risk between midnight and 6am with non-severe storms potentially continuing until 9am. These storms could bring isolated damaging wind gusts, nickel-sized hail and 50-100mm of rain.

In Southwestern Ontario, the risk follows a similar overnight pattern as Deep Southwest, though it’s slightly more delayed. The environment will still support some isolated strong wind gusts and localized flooding, but again, the timing works against widespread severe development. The threat of large hail and a brief tornado is low, but not zero. The risk should ease by the time we hit the late morning hours.

For the Golden Horseshoe, storms are expected to roll through in the mid-to-late morning hours, primarily between 6:00 a.m. and 12:00 p.m. Similar to the regions farther west, the overnight timing limits storm strength, but a few marginally severe cells are possible.

Gusty winds, heavy downpours and nickel-sized hail are the main concerns. The tornado risk is quite low, though not completely off the table. Things should quiet down quickly as we head into the early afternoon

In Central Ontario, storms may get going a bit earlier compared to the GTA, potentially arriving in the pre-dawn hours and continuing through the morning.

The main threat here also leans toward damaging wind gusts and flooding, especially if storms repeatedly track over the same areas. Nickel-sized hail is possible, and while the tornado risk is low, it’s not zero. Timing should help reduce the severity, but there’s still a window for a few stronger cells.

Eastern Ontario is where the severe threat becomes much more notable. As the front progresses into a more unstable environment in the afternoon, the potential for strong storms ramps up.

Damaging wind gusts appear to be the most likely hazard, but one or two tornadoes are also possible, particularly along a corridor from Tweed to Ottawa, where models show the strongest instability and tornado environment overlapping.

Hail around quarter-size and localized flooding are also concerns with any stronger storms that develop.

Southeastern Ontario will also be in the bullseye for strong to severe storms, particularly from late afternoon into the early evening. Kingston through Brockville and into Cornwall sits right along the corridor of stronger wind potential.

Wind gusts may reach damaging levels, with a few storms capable of producing quarter-sized hail. Flooding is also possible in areas that get hit by repeated rounds.

While the tornado risk isn’t as pronounced as the Ottawa Valley, it’s still something we’ll be watching closely.

For our updated map, it’s largely unchanged from our preliminary forecast. The main changes we made was shrinking the ‘widespread’ risk zone to cover Eastern Ontario only. The latest data suggests that the Niagara region is less likely to see storms so the support for a widespread risk is no longer there.

We have also extended the isolated risk into the rest of Southwestern Ontario to cover the very questionable severe risk during the overnight and early morning hours.

For the tornado risk, while there is a non-zero risk for a tornado across all parts of the severe risk, we have focused it on the Ottawa Valley. This is where the latest model data continues to show the strongest tornado risk. Mainly during the mid to late afternoon hours.

There is also a more heightened tornado risk along the London to Hamilton corridor during the morning hours. While the risk isn’t super strong, this is where we believe a tornado is most likely to occur if one does occur in the morning.

The storm risk should taper off around the dinner hour as storms move out into Quebec and Upstate New York.

Heat Wave Ends With a Bang: Widespread Severe Thunderstorm Threat for Southern Ontario on Thursday

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As Southern Ontario continues to deal with a prolonged heat wave, there is some relief on the way. A cold front is expected to sweep through the region on Thursday, bringing temperatures back down to near-seasonal levels. But unfortunately, that relief won’t come quietly.

We’re closely watching Thursday for the potential of severe weather across much of Southern Ontario.

Thunderstorms are expected to fire up along the cold front as it moves through the province, with the potential for widespread severe storms especially across Eastern Ontario, Central Ontario and possibly parts of the Greater Toronto Area (GTA) during the morning and afternoon.

These storms may pack a punch, bringing strong wind gusts, large hail, heavy rain and possibly even an isolated tornado. The best chance for any rotating storms (and tornadoes) will be in Eastern Ontario later in the day when the environment becomes more favourable for storm organization.

With more high-resolution models coming into range, we’re getting a better handle on how things may play out. Based on this data, we’ve put together a preliminary forecast map showing where the greatest risk for severe weather currently appears to be.

That said, this event is still just under 48 hours away, and plenty could still change. The timing, placement and severity of storms may shift, so expect updates over the next couple of days. We’ll be keeping a close eye on the data and will continue to post updates as things evolve.

ESTIMATED TEMPERATURE in °C - MAP FROM WEATHERBELL

At this point, it looks like the cold front will reach the western parts of Southern Ontario sometime during the morning hours. The strongest environment for severe weather will be just ahead of the front. But because of the early timing, the threat for severe storms in Southwestern Ontario and along the Lake Huron shoreline looks more limited.

Still, the setup could be just strong enough to trigger a few marginally severe storms by late morning or early afternoon as activity moves into Central Ontario and the Golden Horseshoe.

SIMULATED RADAR - MAP FROM WEATHERBELL

As the cold front continues eastward into the afternoon, this is when we expect storm activity to really ramp up. With daytime heating providing an extra energy boost, we’re watching the Peterborough to Bancroft corridor around noon, with storms potentially reaching Kingston and the Ottawa Valley by early to mid-afternoon.

Storms are expected to move out of Ontario and cross into New York and Quebec around the dinner hour. However, this is subject to change depending on the timing of the cold front.

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Given the setup, we’ve gone with a ‘widespread’ (level 2 out of 5) severe risk for much of Eastern Ontario. This includes the potential for several severe thunderstorms capable of producing damaging wind gusts, hail and heavy rainfall.

We’ve also extended this risk into parts of the Niagara region where some models are hinting at rapid storm development during the early afternoon before storms cross the border.

The rest of Southern Ontario, excluding Deep Southwestern Ontario and the Lake Huron shoreline, falls under an ‘isolated’ (level 1 out of 5) severe risk. Most storms in these areas will likely stay below severe limits, but a few could briefly become marginally severe during the morning or early afternoon.

Currently, Deep Southwestern Ontario and Northeastern Ontario are not in the risk zone for severe weather on Thursday. That’s due to the early arrival of the cold front which will likely move through these areas before storms have a chance to fully develop. That could change should the cold front arrive later in the day when the environment is strongest.

ESTIMATED Morning LOW in °C - MAP FROM WEATHERBELL

In the wake of the cold front, temperatures will drop significantly Thursday night into Friday morning. Some higher elevation areas in Central Ontario could wake up to morning lows in the upper single digits!

Most of Southern Ontario will see lows in the low to mid teens, which will be a welcome change after several nights of muggy 20°C+ lows.

ESTIMATED DAYTIME HIGH in °C - MAP FROM WEATHERBELL

Daytime highs on Friday will also cool back to near-seasonal values, with most of the region seeing mid-20s. But enjoy it while it lasts. A gradual warm-up is expected over the weekend with temperatures climbing back into the upper 20s and even low 30s by early next week.

Strong Severe Storms Possible in Central Alberta & Saskatchewan, Uncertainty Further East and into Manitoba

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There are two areas across the Prairies where there is the risk of severe thunderstorms today. The difference between these two areas, however, is the likelihood of storm development, with storms in Central Alberta and Saskatchewan looking much more likely to occur than those in Eastern Saskatchewan and into Manitoba.

A cold front that will track through Alberta and Saskatchewan today is expected to begin triggering thunderstorm development early this afternoon in West Central Alberta. These storms should intensify into a line of strong severe thunderstorms as they approach the QE2 corridor, particularly around Red Deer.

This line of storms should maintain its strength for several hours, travelling eastward across Alberta through the afternoon. The storms will then cross into Saskatchewan by the late afternoon/early evening and continue their eastward trajectory, gradually weakening later into the evening and overnight.

Borderline destructive wind gusts of up to 120km/h are possible from Red Deer eastward towards Saskatoon as the line of severe thunderstorms move through the region. Furthermore, hail as large as golf balls and localized flooding are concerns, along with the possibility of one or two embedded tornadoes.

Additional scattered thunderstorms could pop up behind the main line in both Alberta and Saskatchewan throughout the day and continuing overnight, but these storms are expected to be weaker. For those attending the Stampede today, there is the chance for an isolated storm, but the greatest risk for severe weather will remain to the north.

Meanwhile, there is also the risk of severe thunderstorms in Eastern Saskatchewan, along the Manitoba border, and eastward into Manitoba as the cold front makes its way into this area. In particular, parts of Southern Manitoba could be the main target of these storms.

Modelled CAPE (Convective available potential energy) as of 5PM CT highlighting southwestern Manitoba as the area with the most energy

All the ingredients for severe thunderstorms are expected to be in place today in this area, with heat and energy funnelling northward throughout the day ahead of the arrival of the front. Despite this, a strong cap will also be in place, so whether or not storms actually form remains questionable. Short-term weather models are not even showing any thunderstorms developing in this area, further cementing the uncertainty here.

IF thunderstorms end up breaking through the cap, it’s not expected to occur until the evening, but the storms could become quite strong. Large hail will be the main concern with these potential storms, with golf ball-sized or larger appearing possible. Strong wind gusts and torrential rainfall, possibly leading to localized flooding, could also be associated with storms that develop. This situation will certainly bear monitoring throughout the day.

It’s also worth noting that temperatures across the Prairies, with the exception of most of Southern Manitoba, can expect to see more comfortable temperatures tomorrow following the passage of the cold front today.

Questionable Daytime Storms Followed By More Organized Nocturnal Threat in Saskatchewan & Manitoba Thursday

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The cold front which triggered severe weather across Alberta and into Western Saskatchewan yesterday will continue its track eastward today, bringing the risk of severe weather into Eastern Saskatchewan and Manitoba. Similar to yesterday, storm development is questionable throughout the afternoon and evening, with any storms that do develop likely to become severe. There is, however, a much stronger nocturnal risk in place for some areas.

The possibility of isolated thunderstorm development will begin in the mid-afternoon and continue through the evening, starting in Saskatchewan and extending eastward into Manitoba with the gradual movement of the cold front. Weather models disagree with where and when these storms might occur and there is a distinct lack of organization with the storms that do show on the models.

If thunderstorms end up developing during this time, the environment will lead them to likely become severe. These storms could end up being capable of producing hail as large as ping pong balls and strong wind gusts up to 100km/h. There is a small chance that one or two of these storms could produce a tornado, with the risk of this increasing for more southern storms.

The greatest severe thunderstorm threat arrives after midnight, as a large cluster of storms will likely move into Southeastern Saskatchewan and Southwestern Manitoba from south of the border. These storms are expected to be stronger than the ones that could develop during the day and they will track across Southern Manitoba through the early morning hours and eventually exiting into Ontario.

The nocturnal thunderstorms that move through this region may produce up to golf ball-sized hail and damaging wind gusts in excess of 100km/h. There will be a broad region of rain surrounding these thunderstorms and this could lead to some localized flooding as the storms track eastward.

Modelled temperature anomaly for Thurday shows Temperatures 5-10+°C above seasonal across most of Saskatchewan and Manitoba, courtesy of weatherbell.

We have also found ourselves in a bit of a heat wave across most of Saskatchewan and Manitoba for the next couple of days. Temperatures are expected to climb into the low and mid 30s across parts of the region today and tomorrow, which is 5-10°C above the seasonal average for this time of year. With the humidity, it could feel closer to 40°C in some areas.

While more comfortable temperatures move into Saskatchewan on Friday and then Manitoba on Saturday, and this not being nearly as hot as it can get in the summer months, it’s important to be mindful of dealing with the bit of heat while it’s here.

If you spend a great deal of time outdoors, it is crucial to stay hydrated by sipping on water throughout the day and aiming to drink at least one cup of water every 15 minutes, continuing to do so even after you’ve gone inside. We know that there is often nothing better than a cold beer on a hot day, but remember that alcohol is actually dehydrating so make sure to drink plenty of water as well if you indulge in your adult beverage of choice.

Your body loses electrolytes from sweating, so sports drinks that are high in electrolytes can help replenish what has been lost. Salty snacks are also helpful when it comes to regaining lost electrolytes.

Other tips for staying cool include wearing lightweight, light-coloured clothing and limiting direct sun exposure, if possible. Many municipalities offer public spaces with air conditioning where residents can go to cool off, especially those without central air in their homes/apartments.

This is surely not the last we’ll see of these temperatures this summer so keep these tips in mind and have a plan in place if you must spend long periods of time outdoors in the heat.

Boom or Bust: Widespread Severe Thunderstorms Might Develop Across Alberta & Saskatchewan Wednesday as the Heat Breaks

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There is a widespread threat of active weather across much of Alberta and Saskatchewan on Wednesday. This is a result of a cold front that will sweep through the region, breaking the heat and likely triggering some strong severe thunderstorms in the afternoon and evening. However, It’s looking like a ‘Boom or Bust’ sort of day in which thunderstorms could remain capped across most of the region, but if storms do develop, they could become quite strong.

The greatest threat for severe weather will be in parts of Northern Alberta, stretching northeastward from Edson through Whitecourt and beyond the Slave Lake area, highlighted in orange on our forecast map. The environment in this area will be able to support supercell thunderstorms that could develop in the Northern Foothills beginning early this afternoon, around 12-2pm.

The storms in this area could be capable of producing very large hail, as big as standard billiards balls, and damaging wind gusts in excess of 100km/h. They are expected to travel northeastward across Alberta throughout the day and into Saskatchewan overnight. These will be fast moving storms so localized flooding from heavy rain is not a concern, but it is possible that we could see a tornado or two form in this region.

Additional development of slightly weaker, but still severe, thunderstorms could extend southward towards Calgary and through Southern Alberta beginning in the early afternoon. The likelihood storms initiating, however, decreases the further south you go. If storms do end up forming through this area, they are expected to quickly track east-northeastward across Alberta and into Saskatchewan by the late afternoon.

There is also the chance that the storms could skip over Southern Alberta completely, as the cold front pushes through, and instead develop in Southwestern Saskatchewan in the late afternoon and early evening. If these storms end up developing in either province, they are expected to pose more of a wind risk than a large hail risk. Given the environment that the storms could form in, damaging wind gusts up to 120km/h are possible and a lack of moisture should limit hail to the size of quarters and smaller.

Modelled temperature anomaly for wednesday shows Temperatures 5-10°C above seasonal, courtesy of weatherbell.

On top of the severe thunderstorm threat, today will also be the warmest day of the minor heat wave in Central and Southern Alberta. Temperatures are expected to climb into the mid 30s across most of Southern Alberta, which is 5-10°C above the seasonal average for this time of year.

It’s best to limit your time outside in this heat, especially since heat exhaustion can set in fairly quickly if you’re not careful.

If you do spend a great deal of time outdoors, it is crucial to stay hydrated by sipping on water throughout the day and aiming to drink at least one cup of water every 15 minutes, continuing to do so even after you’ve gone inside. We know that there is often nothing better than a cold beer on a hot day, but remember that alcohol is actually dehydrating so make sure to drink plenty of water as well if you indulge in your adult beverage of choice.

Your body loses electrolytes from sweating, so sports drinks that are high in electrolytes can help replenish what has been lost. Salty snacks are also helpful when it comes to regaining lost electrolytes.

Other tips for staying cool include wearing lightweight, light-coloured clothing and limiting direct sun exposure, if possible. Many municipalities offer public spaces with air conditioning where residents can go to cool off, especially those without central air in their homes/apartments.

This is surely not the last we’ll see of these temperatures this summer so keep these tips in mind and have a plan in place if you must spend long periods of time outdoors in the heat.