Strong Severe Thunderstorms with Tornado Risk Once Again Target Edmonton and Parts of Central & Northern Alberta Tuesday

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It has been a seemingly never-ending pattern of severe weather for Central and Northern Alberta lately and unfortunately, that pattern will continue today. We are once again looking at the possibility of strong severe thunderstorms that could impact parts of Central and Northern Alberta, including Edmonton, beginning this afternoon and continuing through the evening.

The environment will be favourable for the development of supercell thunderstorms today. There will be plenty support for these storms, with CAPE values exceeding 2000J/kg in some areas, along with a considerable amount of shear and moisture. A low that will move through the province this afternoon will then be the trigger that causes the storms to develop.

Thunderstorms are expected to fire up early this afternoon in the Foothills. From there, they will track eastward, into the most favourable environment by the late afternoon and continuing through the evening. The greatest severe threat will be in the 5-10pm timeframe and those in the Edmonton area could see severe weather in the window of 6-9pm.

As we get later into the evening, after around 10pm, the storms are expected to weaken as they gradually continue east towards the Saskatchewan border and most thunderstorm activity should end by midnight.

Hourly Precipitation at 5Pm MDt, courtesy of weatherbell.

The strong supercell storms this evening could have the potential to produce very large hail that could be as large as tennis balls, damaging wind gusts in excess of 100km/h, and very heavy rain. The rain will be a concern particularly in Edmonton, which is just inside the area at risk for the strongest storms, since there has been considerable flooding after every thunderstorm that has tracked through the city lately.

There will also be a widespread risk for severe thunderstorms that are expected to be slightly weaker, in an area that surrounds the highest risk. This covers Hinton, High Prairie, Slave Lake, Cold Lake, and Camrose, with Rocky Mountain House and Fort McMurray just inside the risk area.

The storms in this region will likely still be able to produce damaging wind gusts above 100km/h, but the hail associated with them is expected to be a bit smaller, maxing out at the size of a golf ball.

Beyond this region, there is a much more isolated severe risk in an area that covers Red Deer, Jasper, Grande Prairie, Peace River, and north to the Northwest Territories border.

It’s important to note that today’s thunderstorms will have a tornado risk associated with them, but this risk is the most significant for the area marked by hatching on our forecast map, where the strongest storms are expected. This includes Edmonton, Edson, Whitecourt, and Lac La Biche.

With the threat of tornadoes today, please make sure that you have a plan in place in the event that severe weather approaches your area. Make sure to have all of your devices charged and that you have more than one way to receive critical weather alerts.

It’s likely that we will be going live later this afternoon, as the storms start to strengthen, so be sure to tune in at instantweather.ca/live.

Multiple Rounds of Severe Thunderstorms Expected Across Southern Ontario on Monday

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After a relatively quiet stretch of weather, Southern Ontario is heading into a much more active pattern on Monday as multiple rounds of thunderstorms threaten a wide swath of the province. Some of these storms could become severe, bringing the risk of damaging wind gusts, large hail and the potential for one or two tornadoes.

The first round of storms has already developed early this afternoon, with a cluster of thunderstorms producing damaging wind gusts as they tracked inland from Lake Huron into parts of the London area. While this initial activity is ongoing, it is only the beginning of what could become a busy weather day across Southern Ontario.

Additional thunderstorms are expected to develop through the afternoon across Southwestern Ontario before spreading into portions of Central Ontario, particularly around the Lake Simcoe region. Exactly where these storms form remains uncertain, as forecast models continue to struggle with pinpointing the locations where new storms will develop.

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The severe weather threat is expected to continue through the afternoon and early evening, when daytime heating will provide the greatest amount of energy for storm development. Storms may continue well into the evening and persist into the early overnight hours, although the overall severe threat should gradually diminish after midnight as the atmosphere begins to stabilize.

Periods of rain and embedded thunderstorms are expected to linger into Tuesday morning before the system finally begins to move out of the region. Another round of potentially severe storms could affect Eastern Ontario on Tuesday afternoon.

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The greatest concern remains across Deep Southwestern Ontario and communities along the Lake Huron shoreline, including Goderich, Sarnia, London, Chatham, Leamington and Windsor.

We have placed this region under a ‘Strong’ severe weather risk. Storms that develop here will have the potential to produce widespread damaging wind gusts capable of downing trees and power lines, hail ranging from toonie-sized up to Timbit-sized, along with the possibility of one or two tornadoes. Torrential rainfall may also lead to localized flash flooding, particularly where multiple thunderstorms repeatedly move over the same communities in a short period of time.

Further north and east, a ‘Widespread’ severe risk stretches across much of Southern and Central Ontario, including Kitchener, Guelph, Hamilton, Toronto, Barrie, Niagara, Hanover, Collingwood and Owen Sound.

The primary threats in this region will be damaging wind gusts and hail up to the size of toonies. While the tornado risk is lower than in Southwestern Ontario, an isolated tornado cannot be completely ruled out if a storm is able to remain isolated and tap into the favourable atmospheric conditions.

An ‘Isolated’ severe weather risk covers the remainder of Central Ontario, including Peterborough, Muskoka, Parry Sound and Algonquin Park. This risk also extends into parts of Northeastern Ontario, including Sudbury and North Bay.

Only a few storms are expected to develop in these areas, but any storm that does form could still briefly reach severe limits with strong wind gusts, hail and frequent lightning.

Given the uncertainty surrounding exactly where storms will develop, everyone across Southern Ontario should keep a close eye on the forecast throughout the day. Conditions can change quickly, and warnings may be issued with little lead time once thunderstorms begin to intensify.

We’ll be tracking every storm as it develops with live coverage on our YouTube channel, along with real-time updates through the free Instant Weather app. If you live anywhere within the risk areas, now is a good time to make sure notifications are enabled so you can receive notifications the moment they are issued.

Widespread Severe Thunderstorm Threat in Southwestern Ontario Sunday With Timbit-Sized Hail and Damaging Winds Possible

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After a few days of below-seasonal temperatures across Southern Ontario, with daytime highs making it feel more like early September, temperatures are back on the upswing over the next few days.

The cooler weather also brought a quieter period for thunderstorm activity, with our last widespread severe weather event occurring on Tuesday.

While no extreme heat is expected in the near future, temperatures will climb slightly above seasonal levels to start the week. Many areas will see daytime highs in the upper 20s or even low 30s on Monday.

That will be enough to increase instability and bring the potential for multiple rounds of thunderstorms beginning Sunday.

Sunday’s severe thunderstorm threat is expected to be mostly confined to Deep Southwestern Ontario, including Windsor, Chatham and Sarnia. Moderate instability combined with strengthening wind shear could create an environment capable of supporting severe storms.

However, there is still some uncertainty about whether storms will develop and exactly where they might form, as there is no obvious trigger such as a cold front.

Instead, storm development will depend on whether isolated cells can form along smaller-scale boundaries, including lake breezes.

Lake breeze-driven pop-up storms will be possible across Southern Ontario. However, outside of the Lake Erie shoreline and Deep Southwestern Ontario, the environment is not expected to be strong enough to support anything more than isolated, non-severe storms.

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The focus is expected to remain on Southwestern Ontario on Monday, although more widespread thunderstorm development appears increasingly likely as a cold front potentially sweeps through later in the day.

The timing of that cold front is still uncertain and will have a significant effect on the severity of Monday’s storms. A later arrival during the prime hours of daytime heating would likely result in a stronger severe weather threat compared to an evening arrival.

At this point, a wide swath of Southwestern Ontario, including Windsor, Sarnia, London, Hamilton, Kitchener, Goderich, Hanover and Owen Sound, could see severe storms on Monday.

There is also an isolated severe risk extending into the Greater Toronto Area and portions of Central and Northeastern Ontario, including Barrie, Peterborough, Muskoka, Parry Sound, North Bay and Sudbury.

We’ll have more details about Monday’s storm risk, including the expected hazards and timing, in a separate forecast.

DATA FROM WEATHERBELL

For Sunday, isolated thunderstorm activity is possible across Southern Ontario beginning during the early afternoon and continuing into the evening.

Most of these storms are expected to remain below severe levels, with small hail, strong wind gusts and heavy rainfall as the main threats.

The greatest concern for severe weather will be across Deep Southwestern Ontario, extending along the northern Lake Erie shoreline and into the Hamilton and Niagara regions.

If lake breeze boundaries can trigger storms in this area, the environment could support a few storms reaching severe levels. Damaging wind gusts and large hail would be the primary threats.

Weather models often struggle to predict lake breeze-driven pop-up storms. However, the latest data has consistently focused on the Windsor to Leamington corridor as the area most likely to see a storm between 5 and 9 p.m.

Additional thunderstorm activity could develop farther north and east, including around Sarnia, Chatham, London and Hamilton, although models are less certain about storm development in these areas.

The severe weather risk should quickly diminish after sunset, around 9 p.m., as storms lose the daytime heating that helped fuel their development.

DATA FROM WEATHERBELL

Large hail and damaging wind gusts will be the primary threats from any severe storms that develop across Deep Southwestern Ontario on Sunday.

However, increasing wind shear during the early evening could create a narrow window capable of supporting a brief spin-up and an isolated tornado.

The latest model data shows an elevated Significant Tornado Parameter across Essex County. This parameter highlights areas where the atmospheric ingredients could support tornado development.

The most favourable environment appears to be concentrated over Essex County, although it may extend into Chatham-Kent and along the Lake Erie shoreline.

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We have a ‘widespread’ severe risk for Windsor, Leamington, Chatham and Sarnia. This risk is driven by the potential for damaging wind gusts and hail up to the size of a Timbit. An isolated tornado cannot be ruled out.

There is an ‘isolated’ severe risk farther north and east along the Lake Erie shoreline, including Grand Bend, London, St. Thomas, Woodstock, Tillsonburg, Brantford, Hamilton and Niagara Falls.

A few storms in this area could reach marginally severe levels, producing hail up to the size of a quarter and isolated damaging wind gusts.

Across the rest of Southern Ontario, isolated non-severe thunderstorms are possible throughout the afternoon and early evening, including across the Golden Horseshoe and portions of Central and Eastern Ontario.

While these storms are expected to remain below severe levels, anyone planning to be outside or on the water should closely monitor the radar.

Be prepared to seek shelter indoors if a storm approaches, as even non-severe thunderstorms can pose a significant safety risk due to lightning, strong wind gusts and small hail.

Wildfire Smoke Could Hinder Severe Thunderstorm and Tornado Threat for Edmonton and Parts of Central & Northern Alberta Saturday

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The risk for severe weather returns to Edmonton and parts of Central and Northern Alberta with the possibility of severe thunderstorms across the region beginning this afternoon and continuing into the overnight hours.

In yesterday’s thunderstorm outlook from Environment Canada, they had a High Risk for this region. That High Risk has since been downgraded to a Moderate Risk, likely due to the impact that wildfire smoke will have on the potential development of thunderstorms later today.

Smoke from wildfires in British Columbia and the US Pacific Northwest has been significantly impacting air quality at ground level across Alberta over the past few days. However, the presence of smoke higher up in the atmosphere can greatly influence our weather conditions.

Modelled Vertically Integrated Smoke at of 12pm MDT, Courtesy of WMI.

When we have thick smoke throughout the atmosphere, not as much sunlight is able to reach the ground and as a result, it end ups being a few degrees cooler at the surface than expected. A decrease in surface heating while the air aloft is able to heat up also greatly reduces the instability and creates a capping inversion that could block thunderstorm development.

Despite the smoke, there is still a chance that we could see some severe thunderstorms fire up today, but it is not a guarantee. Models are showing that a decent amount of instability could still be available, along with plenty of moisture and shear, to fuel thunderstorms if they are able to break through the cap.

Thunderstorm activity could initiate early this afternoon, particularly in the Foothills, and storms that develop are expected to gradually track northeastward through the remainder of the afternoon and into the evening and overnight hours, with additional storms possibly popping up through this period.

Hourly Precipitation at 5Pm MDt, courtesy of weatherbell.

The storms that may end up forming today will have the potential to become severe across parts of Central and Northern Alberta, in the area in yellow on our forecast map. In this region, the storms may be able to produce large hail up to the size of tennis balls, damaging wind gusts above 100km/h, and heavy rain. The hatched area on the map, which includes Edmonton, Red Deer, Rocky Mountain House, and Edson, will also have an isolated tornado risk.

Today’s severe weather risk could end up being a bust as a result of the wildfire smoke. However, with Edmonton potentially in the bullseye with a tornado risk, we will certainly be keeping a close on how things come together this afternoon.

Winnipeg & Southeastern Manitoba Under Tornado Threat Friday, but Storm Development is Questionable

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A strong severe weather risk returns to Southeastern Manitoba later today, but the entire situation is very questionable and there’s a possibility that there are no storms at all in this region.

The low that has been tracking across the Northern Prairies continues to make its way through Northern Manitoba this morning and it will move into Northern Ontario later today. Thunderstorms were triggered by a trough behind the warm front of this low in Northern Alberta and Saskatchewan yesterday and they extended into Southern Saskatchewan and into Manitoba overnight.

These storms are continuing across Southern Manitoba this morning, some of which have become severe, and this is where the first question mark for later development arises.

In order for additional thunderstorms to initiate later, this morning’s storms will have to clear out of the area early enough for sufficient surface heating to occur. If these storms do manage to exit the region early enough, the environment will be well suited for stronger severe thunderstorms to then begin to develop later this afternoon and into the evening.

The position of the trough that has been triggering thunderstorms will also play a large role in when and where more storms might initiate. In this morning’s latest runs, most short-term weather models are hinting at the trough being positioned in Northern Ontario by the time more thunderstorms fire up, which would keep the greatest severe threat to the east.

If everything manages to come together, with the morning storms clearing early and the trough remaining in Manitoba later this afternoon, there is a distinct possibility that some strong thunderstorms could impact Southeastern Manitoba through the evening. Storms that could affect this region will have potential to produce some very large hail, especially to the east of the Red River Valley. There will also be the risk of damaging wind gusts that could exceed 100km/h, torrential downpours and even a tornado.

While today’s severe weather risk could very easily end up being a bust, it’ll be a good idea to be prepared in the event that strong thunderstorms do end up forming. Make sure to have your devices all charged and that you have multiple ways to receive weather alerts and updates.

If the severe risk manages to materialize in Manitoba later on, we will very likely be live-streaming coverage of the storms, so be sure to join us at www.instantweather.ca/live!

Widespread Severe Thunderstorm Risk Across the Northern Prairies Thursday; Tornado Threat in Northern Saskatchewan

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Today, there will be the widespread potential for severe thunderstorms across Northern Saskatchewan and Manitoba, and into parts of Northern Alberta. Meanwhile, most of the rest of the Prairies will be under a more isolated risk.

A low that is over Northern Alberta this morning will move into Saskatchewan this afternoon and its cold front will be the trigger for thunderstorm development. Although there won’t be a great deal of instability, with CAPE values below 1000J/kg for most of the region, there will be more than enough shear to still support thunderstorms once they form, especially for more southern areas.

We are already seeing some non-severe thunderstorms this morning in Northeastern Alberta and Northwestern Saskatchewan. It’s possible that one or two of these storms could become severe, especially if they can persist into the afternoon.

Hourly Precipitation at 7Pm MDT/CST, 8pm CDT , courtesy of weatherbell.

It’s during the afternoon that we are expecting to see additional development across the Northern regions of all three Prairie provinces, which will gradually track eastward with the low through the evening and overnight.

For the most part, we’re expecting that these will be garden variety severe thunderstorms across the region, with the main threat being strong wind gusts that could exceed 100km/h along with the possibility of up to toonie size hail and heavy rain.

There is, however, a slightly stronger severe risk in parts of Northern Saskatchewan and crossing the border into Alberta. This particular area, which includes Cold Lake, Meadow Lake, and Prince Albert, could potentially see storms that are capable of producing up to golf ball size hail, as well as an isolated tornado.

The presence of wildfire smoke in the atmosphere could certainly hinder thunderstorm development today, especially where the smoke is much thicker, closer to the Northwest Territories border. The good news is that we’re expecting today’s thunderstorms to be very moisture-laden, and there is also the possibility of widespread heavy rain not associated with thunderstorm activity. This will be beneficial for firefighting efforts across Northern Saskatchewan and Manitoba, as long as no additional fires are ignited by lightning strikes.

Strong Severe Storm Risk Targets Southern Ontario Tuesday With Damaging Winds, Toonie-Sized Hail and Tornadoes Possible

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After an active storm day on Saturday brought a rare tornado warning to the Greater Toronto Area along with several reports of damaging winds, Southern Ontario is set to face another severe thunderstorm threat on Tuesday.

The strongest risk appears to be focused along the Highway 401 corridor, stretching from London through the Greater Toronto Area and into Kingston. Storms during the afternoon and early evening could bring widespread damaging wind gusts, up to toonie-sized hail and one or two tornadoes.

Before the main event, morning storms may provide an early wake-up call for parts of Southwestern Ontario and the Golden Horseshoe as a complex of storms tracks into the region from Michigan during the early morning hours on Tuesday.

While most of these storms should remain non-severe, some stronger pockets could bring marginally severe wind gusts, large hail and even a very low tornado threat.

In the wake of Tuesday’s storm threat, which is expected to end by the evening, a cold front will usher much cooler air into Southern Ontario.

Daytime highs on Wednesday could struggle to reach the 20°C mark, making it feel more like early autumn. You may find yourself reaching for the comfort of a pumpkin spice latte instead of a cold summer refreshment!

DATA FROM WEATHERBELL

A mesoscale convective system (MCS) over Michigan is expected to slide into Southern Ontario overnight and early Tuesday morning, first affecting areas east of Lake Huron between approximately 1 and 3 a.m.

As the complex moves inland, some stronger pockets could produce wind gusts exceeding 90 km/h and hail up to the size of a quarter.

There is some uncertainty over how strong this storm complex will remain as it tracks eastward into Central Ontario and the Golden Horseshoe between approximately 3 and 6 a.m.

Weather models tend to struggle with these types of systems. They can sometimes generate their own energy and maintain or strengthen themselves in an environment that would otherwise appear unsupportive of severe weather.

A brief spin-up capable of producing an isolated tornado cannot be completely ruled out, although this is considered very unlikely given the overnight timing.

The marginal severe threat associated with this complex could continue into the mid-morning hours as it reaches the Niagara Region and communities along the northern Lake Ontario shoreline.

The morning storms are expected to clear out by late morning, potentially setting the stage for a more widespread and intense severe weather threat beginning early Tuesday afternoon.

DATA FROM WEATHERBELL

There is still some uncertainty surrounding the timing of the afternoon threat, especially since multiple rounds of storms may be possible.

The afternoon risk will also depend heavily on how quickly the morning storms move out. This will determine how much daytime heating can occur before the next round develops, likely along a cold front moving through the region during the afternoon.

Based on the latest data, the greatest chance for storm development appears to be along a line stretching from Sarnia through London and into the Greater Toronto Area, generally following the Highway 401 corridor.

Storms could begin developing during the early afternoon before tracking southeast toward the Lake Erie and Lake Ontario shorelines. This would bring the threat into Hamilton, the Niagara Region, Prince Edward County and Kingston later in the afternoon.

In addition to the cold front, a warm front will track through Central and Eastern Ontario during the afternoon. This could spark isolated severe storms around Lake Simcoe and into the Ottawa Valley.

However, the strongest environment is expected to develop around the Lake Ontario and Lake Erie shorelines. These areas should experience several hours of daytime heating after the warm front moves through during the morning, adding further instability before the cold front sweeps through later in the day.

The timing of the cold front will be critical. If it moves through too early, substantial storm development may not occur until the front begins moving south of the border, decreasing the risk to our side of the border.

If it is delayed, storms could begin developing farther northwest and have more of Southern Ontario to track across during the peak of daytime heating, potentially increasing the overall severe weather threat.

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Based on the potential for widespread damaging wind gusts, we have introduced a ‘strong’ severe risk for London, St. Thomas, Woodstock, Tillsonburg, Brantford, Kitchener, Hamilton, Niagara, Guelph, Mississauga, Toronto, Newmarket, Oshawa, Belleville, Picton and Kingston.

Other hazards within this zone include hail up to the size of a toonie and the potential for one or two tornadoes.

Localized flash flooding may also be a concern, particularly in urban areas that receive multiple rounds of storms within a short period.

Outside the strongest risk zone, we have an expansive ‘widespread’ risk covering the remainder of Southwestern Ontario, southern portions of Central Ontario and the Ottawa Valley.

This includes Windsor, Chatham, Sarnia, Goderich, Hanover, Orangeville, Barrie, Peterborough, Bancroft, Pembroke, Renfrew, Smiths Falls, Ottawa, Brockville and Cornwall.

Storm hazards in this zone include damaging wind gusts, hail up to the size of a toonie and the possibility of an isolated tornado.

For the Bruce Peninsula and areas east of Georgian Bay, including Muskoka and Algonquin Park, we have introduced an ‘isolated’ severe risk. However, most of the severe thunderstorm activity is expected to remain south and east of this region.

DATA FROM WEATHERBELL

After a second cold front moves through late Tuesday evening, it will usher in a much fresher air mass across Southern Ontario.

Morning temperatures on Wednesday could fall into the upper single digits across some of the more elevated portions of Central Ontario.

It may continue to feel like pumpkin spice season throughout Wednesday, with daytime highs in many areas struggling to climb above 20°C.

Deep Southwestern Ontario, communities along the Lake Ontario shoreline and parts of Eastern Ontario currently have the best chance of reaching the low 20s on Wednesday.

The coldest conditions will be found across the higher elevations of the Dundalk Highlands and into cottage country, where daytime highs on Wednesday could remain in the upper teens.

Those temperatures would be more typical of a crisp autumn day in early September than the middle of summer!

Thankfully, the cooldown should be short-lived, with more seasonal temperatures expected to return by the end of the week and into the weekend.

Dangerous Tornadic Supercells Capable of Massive Hail & Destructive Wind Gusts Possible Northeast of Edmonton Saturday; Strong Severe Thunderstorm Risk Extends Across Alberta & Saskatchewan

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The week of daily severe weather risk in Alberta continues on Saturday, and much of Saskatchewan, with the greatest threat we’ve seen so far this week.

Not only are we looking at the possibility of strong severe thunderstorms across a considerable stretch of both Alberta and Saskatchewan today, but there is also the risk for some significantly strong storms to the east and northeast of Edmonton, in an area that includes Vegreville and St. Paul.

Today’s environment will be primed for the formation of strong supercell thunderstorms.

Models are showing that there will be an incredible amount of instability across the region today, with well over 3000J/kg of CAPE (Convective Available Potential Energy) expected for the Edmonton area. CAPE values of this magnitude are very uncommon for areas this far north, which indicates how strong of a risk we are truly looking at.

Dew points in the upper teens to low 20s today will provide plenty of moisture. Combined with the significant amount of shear that’s expected through the atmosphere, supercell storms will be easily supported.

Overall, we’re looking at a very dangerous setup that would look more at home in the Great Plains of the United States, not in Central Alberta and Saskatchewan.

A low that is set to develop this afternoon, and its associated cold front, will be the trigger for today’s severe weather. The location of this low will be the key to where the very strong thunderstorms will end up impacting.

As it stands, it appears that the low will set up over Edmonton, which would bring the greatest severe threat to areas northeast and east of the city.

Future Surface weather map with the positions of highs, lows, and fronts displayed for 6pm MDT/CST on Saturday, courtesy of the national weather service.

There have already been some severe thunderstorms in Northern Alberta and Southeastern Saskatchewan this morning, but these will just be a precursor of what’s to come.

Additional storms could begin to initiate early this afternoon, mostly in the Foothills, but there could be some isolated development across Central Alberta and into Saskatchewan. As we progress through the afternoon, we are expecting to see more storms develop, all of which will move along a mostly northeastward trajectory.

The greatest severe threat will be through in the evening and into the overnight hours, as the storms encounter their most ideal environmental conditions. The strongest of these storms will likely impact areas to the northeast of Edmonton later in the evening, approximately from 10pm to midnight, give or take an hour.

Through the overnight hours, the storms will eventually weaken, but there will still be a slight severe risk that continues into the pre-dawn hours.

Hourly Precipitation at 11Pm MDT/CST, courtesy of weatherbell.

As we’ve mentioned, the area to the northeast of Edmonton is under a significant severe weather threat today. The storms that hit this region could potentially produce massive baseball size hail and destructive wind gusts that could be upwards of 130km/h, possibly even higher.

There is also a strong severe risk the covers a large portion of Central Alberta and Saskatchewan, that also extends into Northern parts of both provinces.

The entirety of the area under both the Strong and Significant severe risks today will also have the threat of tornadoes developing. The greatest risk for multiple, possibly strong, tornadoes, however, will be in that Significant risk as well as the surrounding area.

This could end up being a very dangerous day so it is crucial to have a plan in place in the event of tornado warning for your area. You’ll need to know where the best place to take shelter is: the most interior room of the lowest floor, away from any windows.

It’s also very important to have all of your devices charged and to have multiple ways to receive weather alerts.

We have already begun live streaming the severe weather ongoing in Southern Ontario and we will be extending our coverage to include Alberta and Saskatchewan once things start to fire up later. Be sure to join us as www.instantweather.ca/live!

GTA in the Bullseye as Southern Ontario Faces Significant Storm Risk With Tornadoes, Destructive Winds and Timbit-Sized Hail Possible Saturday

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The persistent wildfire smoke that has blanketed Southern Ontario over the past several days is finally on the way out, but it will quickly be replaced by a very different threat.

A potentially significant severe weather event is expected across much of Southern Ontario on Saturday as a strong cold front sweeps through the region. The greatest risk is focused on the Greater Toronto Area and surrounding parts of the Golden Horseshoe, where an intense squall line could produce widespread destructive wind gusts, several tornadoes, large hail and flash flooding during the afternoon.

Toronto, Mississauga, Hamilton, Brampton, Vaughan, Oshawa and the surrounding region could be directly in the path of the most intense portion of the squall line.

Widespread wind damage and power outages will be possible if the squall line develops as currently expected. Flash flooding could also become a major concern across heavily urbanized areas, where torrential rainfall may quickly overwhelm drainage systems and flood roads or low-lying areas.

The severe threat will begin much earlier across cottage country, where isolated storms could develop as early as the late morning or around noon. These initial storms may have a greater chance of becoming supercells and producing tornadoes before they organize into a larger squall line.

This is especially concerning on a summer weekend when many people may be camping, boating or staying at cottages across Simcoe County, Muskoka, the Kawartha Lakes and Algonquin Park. Those in tents, trailers or boats could be particularly vulnerable to fast-moving storms producing destructive winds, large hail and tornadoes.

Anyone spending time in cottage country should have a reliable way to receive weather alerts, keep a close eye on the sky and identify a sturdy shelter before storms arrive. Cell service can be unreliable in some remote areas, so it is important to plan ahead rather than waiting for threatening weather to approach.

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The overall severe threat will begin with scattered morning storms before rapidly increasing around noon and continuing through the afternoon. However, the exact strength and placement of the event will depend on how quickly those morning storms move out and whether lingering wildfire smoke limits daytime heating in Eastern Ontario.

DATA FROM WEATHERBELL

As we often see on days with a strong severe weather risk, there will be a morning storm component. Scattered storms are expected to develop from Lake Huron through areas east of Georgian Bay and into Algonquin Park between approximately 6 and 8 a.m.

While most of these storms should remain below severe limits due to their early timing, a few cells could still bring a marginal severe threat, with wind gusts approaching 90 km/h and hail up to the size of nickels.

More importantly, these storms will play a key role in determining how the severe threat unfolds later in the day. A cold front is expected to quickly follow the morning storms during the early afternoon.

If the morning activity lingers into the late morning, it could limit additional daytime heating before the cold front arrives. This would leave storms developing along the front with a less favourable environment that has already been worked over by the earlier storms.

DATA FROM WEATHERBELL

Another important factor is the persistent wildfire smoke from Northern Ontario that has been locked over Southern Ontario during the past several days.

Current models suggest the smoke should clear out of most of Southern Ontario by late Saturday morning. Based on the latest upper-level smoke data, it should be mostly confined to Eastern Ontario by noon.

This means Southwestern and Central Ontario, along with the Golden Horseshoe, should have no problem warming up as long as the morning storms do not linger for too long.

Eastern Ontario is more uncertain. With smoke potentially lingering into the afternoon, it could filter out enough sunlight to limit daytime heating and inhibit storm development. We recently saw this happen during what had initially appeared to be a strong severe weather threat in Quebec last week.

While it is unlikely that smoke will significantly affect storm development elsewhere in Southern Ontario, any unexpected delay in clearing could reduce the severe threat in some of the stronger risk areas. This remains a possible bust scenario, although it appears unlikely based on the latest data.

DATA FROM WEATHERBELL

The threat will begin to build around noon as a cluster of storms develops from Lake Huron through cottage country and into Algonquin Park. This cluster is expected to eventually organize into a strong squall line, but the storms may remain more isolated during the first few hours of development.

That could allow the strongest tornado potential during the early stages of the event to focus on portions of cottage country. Anyone camping or spending time outdoors should have a reliable way to receive tornado alerts and remain weather aware, as these storms could move quickly and arrive with little notice.

We may also see isolated cells develop ahead of the main line before eventually being absorbed as the cold front races toward them. These isolated storms could present a tornado threat across portions of Simcoe County, York Region and the Greater Toronto Area.

DATA FROM WEATHERBELL

The latest Significant Tornado Parameter data, which highlights where the ingredients for tornado development may be strongest, focuses the greatest potential just west of Toronto around Kitchener, Orangeville and Barrie, extending northward into Bracebridge and Algonquin Park.

This parameter only shows where the environment may be supportive. Storms still need to develop and take advantage of those ingredients.

However, it suggests that any storms that do form could quickly present a tornado threat beginning as early as noon, with the risk continuing to build through the early afternoon.

DATA FROM WEATHERBELL

By the middle of the afternoon, a maturing squall line attached to the cold front is expected to sweep southeastward into a highly favourable severe weather environment.

This environment will extend from Sarnia through Kitchener and into the Golden Horseshoe, potentially reaching the Peterborough to Kingston corridor.

At this point, the primary threat should transition to destructive wind gusts, potentially affecting a wide area along the line.

A few QLCS (Quasi-Linear Convective System) tornadoes, which can develop quickly within a squall line, will also be possible. Embedded supercells or isolated supercells immediately ahead of the line could bring an additional tornado threat.

The squall line is expected to continue southeastward while strengthening as it approaches Lake Ontario and Lake Erie before eventually crossing into the United States.

Since the line may strengthen as it tracks southeastward, the Greater Toronto Area, Niagara Region and communities along the northern shoreline of Lake Erie could face the greatest threat. Widespread wind damage will be possible if the line develops as currently expected.

DATA FROM WEATHERBELL

By the middle of the afternoon, between approximately 2 and 3 p.m., Significant Tornado Parameter data shows an increasingly favourable environment for tornado development across the Greater Toronto Area and from areas east of Lake Simcoe through Peterborough.

There is also a conditional threat west of Ottawa if storms can develop behind the cold front after it moves through Algonquin Park, Pembroke and Renfrew. However, storm development in this area is much more uncertain.

A slight tornado risk will also extend farther southwest into Kitchener, London and Chatham. Isolated supercells developing ahead of the squall line could acquire rotation before being overtaken by the main line.

The tornado threat will shift into Niagara Region and the Kingston to Brockville corridor later in the afternoon, generally between 3 and 5 p.m., as the squall line approaches those areas.

The highest severe risk on Saturday is currently focused on the Golden Horseshoe, including Toronto, Hamilton, Mississauga, Kitchener, Guelph, Brantford, Niagara Falls, Newmarket and Oshawa.

We have placed these areas under a “significant” risk, which is level four out of five on our severe weather risk scale.

This risk is primarily driven by the potential for widespread destructive wind gusts accompanying an intense squall line during the early to middle afternoon.

Several tornadoes will also be possible within this region, especially if isolated supercells develop ahead of the main line. Hail up to the size of toonies or Timbits will also be possible.

Flash flooding could become a major concern, particularly throughout heavily urbanized areas. These locations are more vulnerable to significant rainfall over a short period because pavement and other hard surfaces prevent water from quickly soaking into the ground.

A fairly expansive “strong” risk, which is level three out of five, includes Windsor, Chatham, Sarnia, London, Grand Bend, Orangeville, Barrie, Peterborough, Belleville, Kingston and Brockville.

These areas could see one or two tornadoes, along with widespread damaging wind gusts. Large hail up to the size of Timbits will also be possible.

The “widespread” risk, which is level two out of five, covers Grey and Bruce counties, areas east of Georgian Bay, Muskoka, Bancroft, Smiths Falls and Cornwall.

Damaging wind gusts and large hail up to the size of toonies will be possible. An isolated tornado cannot be ruled out, especially east of Georgian Bay through cottage country.

While we have assigned an isolated risk to the Ottawa Valley and Algonquin Park, this is mainly because storm development is more uncertain in these areas. They are also not expected to be directly affected by the intense squall line.

Any severe threat here will likely come from isolated storms developing during the late morning or early afternoon, potentially after the cold front moves through. An isolated tornado will be possible across Algonquin Park and the Ottawa Valley if storms are able to develop.

Widespread Evacuations as Northwestern Ontario Wildfires Strain Underfunded Provincial Resources

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SOURCE: NOAA

An escalating wildfire emergency is unfolding across Northwestern Ontario, where extreme heat, critically low humidity and strong winds have caused dozens of fires to explode in size, devastated at least one First Nation and forced widespread evacuations.

As of Wednesday, July 15, there were 180 active wildfires across Ontario, with 136 burning in the Northwest Region alone. Dozens remained out of control, while firefighting resources were being prioritized for fires posing the greatest immediate threat to communities, critical infrastructure and public safety.

Crews have been pulled back from some fires because the extreme behaviour has made direct suppression too dangerous. At the same time, the scale of the emergency is renewing questions about whether years of underbudgeting for forest firefighting left the province with less flexibility to position crews, aircraft and equipment before conditions deteriorated.

Ontario budgeted $150 million for Emergency Forest Firefighting this year, despite spending an estimated $271 million last year. A larger initial budget would not necessarily have prevented the current fires or stopped their explosive growth under such extreme weather conditions. However, firefighters have warned that unreliable upfront funding can delay the acquisition and deployment of critical resources when several fires ignite or intensify simultaneously.

Mandatory evacuations are now underway across several First Nations, communities and rural townships in Northwestern Ontario. Other areas, including Ignace, Pickle Lake, Atikokan and Upsala, remain on evacuation standby as conditions continue to evolve.

Beyond the immediate fire zone, enormous smoke plumes have nearly blocked out daylight around Thunder Bay and caused some of the worst air quality Southern Ontario has experienced in years. Smoke has spread into Quebec and the northeastern United States, exposing millions of people to unhealthy and, in some locations, potentially hazardous air.

Nearly 150 Active Fires in Northwestern Ontario

Of the 180 active wildfires reported across Ontario as of Wednesday evening, 136 are burning in the Northwest Region, including 26 new fires that were discovered on Tuesday and 8 more on Wednesday.

As it stands, 63 fires in the Northwest are classified as not under control, five are being held, five are under control, and 63 were being observed. Four fires were declared out during the day.

The number of simultaneous fires has forced officials to prioritize available resources. Fires threatening populated areas, critical infrastructure and evacuation routes are receiving the greatest attention, along with fires where crews have a reasonable chance of safely and successfully slowing their spread.

Some remote fires may be monitored rather than actively suppressed, while personnel and aircraft are directed toward more immediate threats. A fire being observed does not necessarily mean it has been abandoned, as monitoring can be a standard management strategy for remote fires that are not threatening people or infrastructure.

However, with dozens of out-of-control fires and several communities threatened at once, the current situation is placing immense pressure on Ontario’s wildfire response capacity.

How the Wildfire Situation Escalated

Multiple fires were already burning across Northern Ontario during the first week of July, but the situation deteriorated rapidly following a series of lightning strikes produced by thunderstorms that moved across Northwestern Ontario on July 6th and 12th.

A lightning strike does not necessarily cause a tree or surrounding vegetation to immediately erupt into visible flames. An ignition can instead smoulder underground, inside a tree or within dry vegetation for several days before warmer, drier and windier weather allows it to spread.

These are known as holdover fires. They can remain difficult to detect until conditions become favourable enough for them to grow and produce a visible smoke column.

The critical change in conditions arrived on Monday, July 13, when Northwestern Ontario entered a period of extreme heat. Afternoon temperatures climbed into the low to upper 30s while relative humidity fell below 30 percent and winds gusted upwards of 50 km/h.

Wildland firefighters sometimes use the “30-30-30 rule” as a quick indicator of weather capable of supporting extreme fire behaviour. The rule refers to temperatures of at least 30°C, relative humidity of 30 percent or lower and winds of at least 30 km/h. A related warning sign occurs when the temperature rises above the relative humidity value, a situation commonly referred to as crossover conditions.

This combination rapidly dries vegetation, allows flames to spread more quickly and makes direct suppression increasingly difficult and dangerous. Fires can begin crowning through treetops, throwing embers well ahead of the main fire and advancing several kilometres over a short period.

Many parts of Northwestern Ontario reached or exceeded these thresholds beginning Monday. As the extreme heat, low humidity and strong winds have continued on Tuesday and Wednesday, so has the explosive growth of fires across the region.

Not every fire currently burning was caused by the July 6 lightning. Some of the region’s largest fires were detected before then, including Dryden 13 on May 31 and Fort Frances 14 and 15 on June 30. However, holdover fires, along with sparks from the existing fires, may have contributed to the sudden increase in new fire discoveries as conditions have deteriorated over the past few days.

Could Provincial Funding Have Affected the Response?

The scale of the emergency is renewing scrutiny of how Ontario funds its forest firefighting program and whether chronic underbudgeting has limited the province’s ability to prepare proactively for severe fire seasons.

Ontario’s 2026 budget allocates $150 million to Emergency Forest Firefighting. That is $121 million less than the $271 million the province estimates it spent during the 2025-26 fiscal year, representing a reduction of approximately 45 percent compared with last year’s actual spending.

However, the $150-million allocation is $15 million higher than the province originally budgeted for the program last year. The annual budget is also not necessarily a firm spending limit, as additional emergency funding can be approved when wildfire suppression costs exceed the initial allocation.

The broader base budget for the Ministry of Natural Resources is projected to decline from $795 million to $739.5 million, a reduction of $55.5 million. (Ontario’s 2026 Budget)

Experts argue that relying on additional funding after a wildfire emergency has already intensified makes it more difficult to plan and position sufficient resources before multiple fires begin competing for the same crews, helicopters and equipment.

Wildland firefighter and union representative Noah Freedman told the National Observer that insufficient upfront funding can leave the province scrambling to request additional resources after conditions deteriorate.

According to Freedman, logistical problems during the 2025 fire season included a lack of available crews and helicopters in areas where they were needed. He argued that the funding structure can delay resource acquisition and prevent local officials from making proactive decisions before an emergency escalates. (Ontario Association of Fire Chiefs)

Those concerns are particularly relevant during a lightning-driven outbreak. The opportunity to contain a new fire is often greatest while it is still small. If crews or aircraft cannot reach it quickly, a period of hot, dry and windy weather can allow the fire to grow beyond the point where direct suppression is safe or effective.

It is not possible to determine whether a larger initial operating budget would have changed the outcome of any individual fire burning in Northwestern Ontario. The extreme weather experienced this week can produce fire behaviour capable of overwhelming even a well-resourced response.

The decision to withdraw crews from an actively burning area may also be based entirely on immediate safety conditions, rather than staffing or funding. When a fire begins crowning through the treetops, producing long-range embers or advancing rapidly, crews may have no safe option but to retreat.

Still, upfront funding can influence how many crews and aircraft are available, where those resources are positioned and how quickly officials can respond when numerous fires ignite or intensify simultaneously. The current emergency will likely bring further examination of whether Ontario entered the season with enough resources immediately available.

Widespread Evacuations Underway

The rapidly deteriorating conditions have prompted mandatory evacuations across several parts of Northwestern Ontario.

Communities under evacuation orders include Armstrong, Namaygoosisagagun First Nation (Collins First Nation), Gakijiwanong Anishinaabe Nation (Lac La Croix First Nation), Gull Bay First Nation, Lac des Mille Lacs First Nation and Whitesand First Nation.

Evacuation orders are also in effect for the townships of Hutchison, Ramsay Wright, Trottier and Weaver in the Dryden-Fort Frances-Atikokan District.

Cat Lake First Nation, a remote fly-in community surrounded by several fires, was also placed under a mandatory evacuation order Wednesday afternoon.

Fort Hope First Nation, also known as Eabametoong First Nation, and Aroland First Nation have both announced on Wednesday evening that they are evacuating as fires threaten the surrounding area.

Evacuating remote and fly-in communities presents significant logistical challenges. Residents cannot always leave by road, making aircraft availability, safe flying conditions and suitable accommodations in host communities critical parts of the operation.

Authorities have also placed several communities and areas on evacuation standby as the fires continue to spread. These include Ignace, Pickle Lake, Quetico, Crystal Lake, Atikokan, Niobe Lake and Upsala.

Being placed on standby does not mean an evacuation has been ordered. However, residents should prepare to leave quickly if conditions deteriorate. This includes gathering essential medications, identification, important documents, clothing and supplies, along with arranging transportation where necessary.

Residents should closely monitor instructions from local officials and emergency services.

Dryden 13 Devastates Collins First Nation

Dryden 13, also known as DRY013, was first detected on May 31 and has been affecting the Collins, Armstrong and Whitesand First Nation area.

The fire was classified as being held at approximately 14,333 hectares as of June 21. However, the return of hot and dry conditions caused it to grow significantly this week. Its current size remains unclear; however, there are indications that Dryden 13 may have advanced by as much as 50 kilometres on Monday, demonstrating the extreme rate of spread possible under the conditions experienced this week.

The fire advanced rapidly toward Namaygoosisagagun First Nation, also known as Collins First Nation, causing extensive damage and destruction to homes and other buildings. The complete extent of the losses remains unclear, but reports from the community indicate that much, or potentially most, of Collins has been destroyed.

Residents were reportedly forced to flee without the immediate support of emergency services, although all community members had been accounted for based on information available Wednesday morning.

Source: Ontario MPP Sol Mamakwa via X

The fire has also burned along the railway corridor near Armstrong. Horrifying video recorded from inside a CN freight train showed flames burning intensely on both sides of the tracks. Thankfully, the train crew was later safely evacuated.

In their Wednesday evening update, the Ministry of Natural Resources has confirmed that Dryden 13, along with several Thunder Bay fires, have merged with the much larger Thunder Bay 36 fire. This fire has been mapped at just over 350,000 hectares in size and is located within Wabakimi Provincial Park.

Fort Frances 14 Threatens Upsala Area

Fort Frances 14, or FOR014, was detected on June 30 and is burning between Highways 11 and 17 in the Upsala and Lac des Mille Lacs area.

The fire reportedly doubled in size overnight from Tuesday into Wednesday. Earlier Wednesday, the Ministry of Natural Resources announced that the fire had been mapped at 18,102 hectares. However, the province’s online fire map later listed its size at 55,106 hectares. It is unclear whether that difference reflects further growth, improved mapping or an adjustment to the estimated perimeter.

Lac des Mille Lacs has lost power as the fire continues to threaten the surrounding area. An emergency meeting was scheduled in Upsala for Wednesday evening, with the possibility of an evacuation expected to be among the issues discussed.

There are also two other fires southwest of Ignace, Dryden 28 and Dryden 36, adding to the increasingly complex situation in the region.

Fort Frances 15 Burns Through Quetico

Fort Frances 15, or FOR015, is burning entirely within Quetico Provincial Park.

The fire was reported at 11,961 hectares earlier Wednesday, but the provincial fire map later listed it at 48,261 hectares. As with Fort Frances 14, it is unclear whether the substantial difference is the result of rapid growth or updated mapping.

Several other fires are also burning within Quetico Provincial Park and along the Highway 11 corridor, including Fort Frances 36 and Fort Frances 38.

Areas of Quetico Provincial Park have been evacuated or closed, affecting backcountry campers and paddlers. The fires are burning in remote terrain where access is limited, further complicating suppression efforts.

The Ministry of Natural Resources has reportedly withdrawn crews from the Ignace and Quetico fires because of extreme fire behaviour. Crews may be repositioned to protect communities and infrastructure or wait for conditions to become safe enough for suppression work to resume.

Minnesota Fires Cross Into Canada

The wildfire emergency extends beyond Ontario, with numerous lightning-caused fires also burning in Northern Minnesota and the Boundary Waters Canoe Area Wilderness.

U.S. fire officials reported that the Bear Trap Fire and Thumb Fire crossed the international border into Canada after exhibiting active or extreme fire behaviour.

The Thumb Fire is burning approximately 10 kilometres south of Gakijiwanong Anishinaabe Nation, also known as Lac La Croix First Nation. Aircraft have continued suppression efforts on the American side while Canadian authorities respond to the portions that have entered Ontario.

The international border has no effect on the spread of a wildfire, making coordination between Ontario and Minnesota authorities critical as fires threaten communities, parks and remote wilderness areas on both sides. (Minnesota Incident Command System)

Highway Closures Complicate Evacuations

Wildfires have affected several major transportation corridors across Northwestern Ontario.

As of 8 PM on July 15th, Highway 599 remains closed between Highway 516 and Mishkeegogamang First Nation, while Highway 527 is closed between Gull Bay First Nation and Armstrong.

Highway 11 was closed between Highways 633 and 623 along the northern edge of Quetico Provincial Park. That section has since reopened, although wildfire crews and emergency equipment may still be operating in the area. Officials continue to ask motorists to avoid non-essential travel.

These closures can significantly complicate evacuations because many Northwestern Ontario communities have few practical alternate routes. They can also disrupt the movement of emergency personnel, firefighting equipment, food, fuel and other critical supplies.

Smoke Spreads Across Eastern North America

The effects of the Northwestern Ontario wildfires are being felt thousands of kilometres away, as enormous quantities of smoke spread across the Great Lakes and into Eastern North America.

Closer to the fires, smoke has choked portions of Thunder Bay and surrounding areas. At times, it has become thick enough to nearly block out daylight, creating dark and almost apocalyptic scenes during the middle of the day.

The plume began flowing southeastward Tuesday, spreading across the Great Lakes into Southern Ontario, Quebec and the northeastern United States.

Some of the smoke initially remained above ground, but it still affected the weather by limiting the amount of sunlight reaching the surface. This appears to have reduced daytime heating and atmospheric instability, helping suppress what had previously been expected to be a potent severe thunderstorm threat across parts of Eastern Ontario, Quebec and New England on Tuesday.

By late Tuesday, the smoke had begun mixing down to ground level across Southern Ontario. Conditions continued to deteriorate Wednesday as an even thicker plume arrived.

DATA FROM PURPLEAIR

This resulted in some of the worst air quality Southern Ontario has experienced in years. Official Air Quality Health Index readings reached the very high-risk category of 10+ in several communities.

Third-party sensors reported U.S.-scale Air Quality Index values approaching or exceeding 300 to 500 in parts of Southwestern Ontario and the Golden Horseshoe. Values in that range are considered very unhealthy to hazardous.

Toronto was also ranked as having some of the worst air quality among major cities worldwide Wednesday as smoke blanketed the region. (Ontario Air Quality Health Index)

DATA FROM WEATHERBELL

The worst conditions across Southern Ontario are expected to peak between late Wednesday and Thursday afternoon. Some smoke will likely linger into Friday and potentially the weekend, although its intensity and duration will depend heavily on fire behaviour and wind patterns over the next 24 to 48 hours.

Staying Safe During Hazardous Air Quality

Wildfire smoke contains fine particulate matter known as PM2.5. These particles are small enough to travel deep into the lungs and enter the bloodstream, potentially aggravating asthma, heart disease and other respiratory or cardiovascular conditions.

Children, older adults, pregnant people, those with heart or lung conditions and anyone working or exercising outdoors face an increased risk. However, smoke this intense can cause symptoms even in otherwise healthy people.

Residents should reduce or postpone strenuous outdoor activity and spend as much time as possible in a location with cleaner, filtered air. Keep windows and doors closed where it is safe to do so, set central air systems to recirculate and use the highest-quality filter the system can safely accommodate. A portable air purifier with a HEPA filter can also help reduce smoke particles indoors.

However, anyone without air conditioning should not allow their home to become dangerously hot simply to keep smoke outside. If indoor temperatures become unsafe, consider visiting a public cooling centre, library, shopping centre or another air-conditioned location with cleaner air.

Anyone who must go outside should consider wearing a properly fitted N95, KN95 or KF94 mask. Cloth and loose-fitting surgical masks provide little protection against the fine particles in wildfire smoke.

Watch for symptoms including coughing, wheezing, headaches, dizziness, eye or throat irritation, shortness of breath and chest discomfort. Anyone experiencing severe difficulty breathing, chest pain or another medical emergency should seek immediate medical assistance. (Health Canada wildfire smoke guidance)

With extreme fire behaviour continuing across Northwestern Ontario, the full extent of the emergency may not be known for some time.

Fire sizes can change dramatically when officials receive new satellite data or more accurate aerial mapping. This may explain some of the substantial differences between fire sizes announced earlier Wednesday and those later displayed on the provincial fire map.

Weather conditions over the next several days will play a major role in determining whether crews can regain control. Cooler temperatures, higher humidity and lighter winds would help reduce fire behaviour, but meaningful rainfall may be needed to provide more substantial relief.

Fire sizes, classifications, road closures, air quality conditions and evacuation orders may change rapidly. Residents in affected areas should continue following instructions from local officials and emergency services.

Edmonton Area in the Crosshairs for Strong Severe Thunderstorms Tuesday with Threat of Very Large Hail and Possible Tornadoes

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It’ll be yet another day with the threat of strong severe thunderstorms for parts of Alberta. Today’s risk will be along the Highway 43 corridor between Whitecourt and Edmonton, and throughout the surrounding area, including Edson, Drayton Valley, and Westlock.

There will be plenty of instability in the atmosphere across Central Alberta and into parts of Northern Alberta today, with upwards of 3000J/kg of CAPE being shown on weather models beginning this afternoon. Additionally, ample moisture and shear throughout the region will lead to all the necessary ingredients being in place for some strong severe thunderstorms to develop.

Today’s thunderstorms could possibly begin in the Foothills in the mid-to-late afternoon, but it’s more likely that storms will fire up in this area during the early evening. Once the isolated storms do start to develop, they are expected to rapidly strengthen into strong supercells, which will track mostly eastward across the province through the remainder of the evening and overnight.

Hourly Precipitation at 1Am MDT, courtesy of weatherbell.

These severe thunderstorms are expected to reach the Edmonton area sometime in the late evening or shortly after midnight, around 11pm-2am. These thunderstorms could very likely maintain their strength up until this point, however there is also the possibility that the storms will weaken to the west, before hitting Edmonton. Regardless, as we progress overnight and into the pre-dawn hours, and the storms continue tracking eastwards, they are expected to weaken considerably and will likely dissipate before reaching the Saskatchewan border.

The greatest threat from the strong supercell thunderstorms today will be very large hail, which could end up being up to tennis ball size. There will also be the risk of damaging wind gusts in excess of 100km/h, intense rainfall, and even the possibility of a tornado or two.

In the meantime, there will be a more isolated severe risk this afternoon and evening in Southeastern Alberta. The storms in this part of the province aren’t expected to be particularly strong, especially when compared to the storms further north, with the main concern being some strong wind gusts, small hail, and pockets of heavy rain.

Given that today’s strong severe thunderstorms will have tornado potential continuing after dark, especially in such a populated area, it’s crucial to ensure that you have all of your devices charged and that you have more than one way to receive critical alerts. We expect to be live-streaming today’s storms once they begin to develop, along with those in Ontario, Quebec, and New Brunswick, so be sure to tune in!

Potential Record-Breaking Heat to Fuel Severe Thunderstorm Threat Across Southern Ontario Tuesday

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Dangerously hot temperatures are returning to Southern Ontario, bringing another multi-day heat wave to the region. This heat wave is expected to peak on Tuesday, when temperatures could climb into the mid to upper 30s across many communities.

As temperatures rise, so does the instability in the atmosphere, and Tuesday will be no exception. The intense heat will help fuel the potential for strong to severe thunderstorms across parts of Southern Ontario.

The greatest severe weather threat is expected to focus on the Ottawa Valley, where a cold front will move through the hot, humid air during the late afternoon and early evening. As the front arrives, it is expected to spark a line of thunderstorms capable of quickly becoming severe.

The environment appears favourable for some of these storms to develop into supercells capable of producing all severe weather hazards, including destructive wind gusts, golf ball-sized hail and a few tornadoes.

Elsewhere across Southern Ontario, widespread thunderstorm development is not expected as there is no well-defined trigger in place. However, isolated storms could still develop along lake breeze boundaries or from outflow boundaries generated by other storms. With plenty of instability available, any storm that manages to form could become severe. Most communities, however, are expected to remain dry on Tuesday.

Join Us on YouTube for Storm Coverage:

We'll be providing comprehensive live coverage of any storms that develop Tuesday on our YouTube channel. Our team will be tracking storms in real time with live radar analysis, warnings, and storm reports, so if severe weather threatens your area, be sure to join us live to help stay informed.

Another developing story that could have significant implications for Southern Ontario’s weather is the rapid increase in wildfire activity across Northwestern Ontario. A large number of new wildfires ignited over the past day, and the smoke from these fires is expected to begin spreading into Southern Ontario as early as Tuesday. An even more significant plume is expected to arrive on Wednesday.

In addition to air quality concerns, this smoke could also influence thunderstorm development on Tuesday by limiting the amount of sunshine reaching the surface. If enough smoke is present, it could reduce instability and lead to fewer storms than currently expected.

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Tuesday is shaping up to be a sweltering day, with temperatures climbing above 35°C across a large portion of Southern Ontario and potentially approaching the 40°C mark in a few locations. That’s before factoring in the humidity, which could make it feel more like the mid to upper 40s.

The hottest conditions are expected in a corridor stretching from Deep Southwestern Ontario through the Golden Horseshoe and into the Ottawa Valley. Afternoon highs here will likely range between 36 and 38°C, with parts of the Greater Toronto Area potentially reaching 39 to 40°C.

One reason the Greater Toronto Area could end up even hotter than surrounding communities is because of the urban heat island effect. Cities are filled with concrete, asphalt and buildings that absorb heat from the sun throughout the day and slowly release it back into the surrounding air. With fewer trees and green spaces to provide cooling, temperatures in urban areas can end up several degrees warmer than nearby rural locations, especially during prolonged heat waves.

The remainder of Southern Ontario can expect highs ranging from 30 to 36°C. Communities located directly along the northeastern shores of Lake Erie and Lake Ontario, as well as the eastern shores of Lake Huron and Georgian Bay, could be 5 to 10°C cooler thanks to cooling lake breezes.

Humidity is not expected to be quite as intense as it was during the late June heat wave, when humidex values approached 50°C in some areas. Even so, it will still make conditions feel like the low to mid 40s, with a few locations around the Golden Horseshoe potentially approaching the upper 40s.

These temperatures can become dangerous very quickly, especially for older adults, young children, people with chronic health conditions and anyone spending extended periods outdoors. Stay well hydrated, avoid strenuous outdoor activities during the hottest part of the day, wear lightweight clothing and seek air-conditioned spaces whenever possible.

Never leave children or pets inside a parked vehicle, even for a few minutes, as temperatures inside can rise to life-threatening levels in a very short amount of time!

DATA FROM WEATHERBELL

The hot, dry weather has also created ideal conditions for wildfire growth across Northwestern Ontario, and we’ve seen exactly that over the past 12 hours.

More than a dozen new wildfires have ignited, with many of them concentrated northwest of Thunder Bay. A southeasterly wind flow is expected to carry smoke from these fires into Southern Ontario over the next several days.

Initially, much of this smoke should remain high in the atmosphere. However, by Wednesday we could be dealing with a significant wildfire smoke event across Southern Ontario as more of the smoke mixes down to the surface, potentially leading to hazardous air quality. More details on that once models start ingesting the data from the new fire.

Even Tuesday’s elevated smoke could influence our weather, particularly across Central and Eastern Ontario. We’ve seen in the past that thicker smoke can reduce the amount of sunlight reaching the ground, limiting daytime heating and making it more difficult for thunderstorms to develop.

As a result, there is a real possibility that Tuesday’s severe weather threat could underperform if the smoke becomes thick enough to suppress storm development.

DATA FROM WEATHERBELL

Assuming the smoke does not significantly interfere, the latest model data shows a line of thunderstorms developing around the dinner hour from North Bay to just north of Ottawa.

The exact timing will depend on when the cold front arrives, but the primary threat window currently appears to be between 4 PM and 10 PM.

These storms are then expected to track southeast through the Ottawa Valley, potentially affecting portions of Central Ontario before continuing into southeastern Quebec and eventually crossing into the northeastern United States.

We could also see isolated thunderstorms develop during the afternoon and early evening across other parts of Southern Ontario. These would likely be triggered by lake breeze boundaries or other localized features that weather models often struggle to resolve.

Any storm that is able to develop could quickly become severe, producing damaging wind gusts and large hail. The greatest tornado threat remains focused across Eastern Ontario.

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Based on the expected environment, we’re forecasting a “Strong” (Level 3 of 5) severe weather risk for Ottawa, Cornwall, Smiths Falls, Renfrew, Pembroke and Deep River. This reflects the potential for widespread damaging wind gusts, golf ball-sized hail, one or two tornadoes and localized flash flooding.

A “Widespread” (Level 2 of 5) severe weather risk extends across the rest of Eastern and portions of Central Ontario, including Brockville, Bancroft, Huntsville, Algonquin Park, Sundridge and North Bay. Confidence is a bit lower than across the Ottawa Valley, but several severe storms remain possible with damaging wind gusts, Timbit-sized hail and an isolated tornado.

The remainder of Southern Ontario is under an “Isolated” (Level 1 of 5) severe weather risk. Most communities in this area will likely remain storm-free. However, if a thunderstorm is able to develop along a lake breeze or another localized boundary, it could produce isolated damaging wind gusts and up to quarter-sized hail.

Widespread Tornado and Large Hail Threat with Another Risk of Severe Thunderstorms in Alberta & Saskatchewan Saturday

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Following yesterday's widespread severe weather, in which multiple tornadoes were reported to have touched down in Central Saskatchewan, as well as one possibly touching down to the west of Edmonton, we're in for yet another day with the risk for strong severe thunderstorms.

For several days, weather models have been showing that the environment could be extremely unstable today, especially across much of Saskatchewan, which could result in a fairly significant severe weather outbreak. Working against this, however, is the likelihood that there could actually be too heat higher up in the atmosphere, which could create a strong capping inversion that would hinder thunderstorm development. This is expected to be the case for much of Southern Saskatchewan today, where there will be a more isolated severe risk. It's important to note that any storms that are able to develop in this region will probably be quite strong.

Shifting northward, the capping should be less of an issue in Central and Northern parts of Alberta and Saskatchewan. Across this large swath of the Prairies, severe thunderstorms are expected to develop much more readily in a favourable environment.

Although there are already some thunderstorms this morning in Central and Northern Alberta, the storms that we are most concerned about are expected to beginning developing early this afternoon in Western Alberta, which will track mostly eastward through the afternoon.

As these storms cross into Saskatchewan early this evening, they could strengthen considerably as they move through the most ideal environment. These thunderstorms are expected to maintain their strength as they cross Saskatchewan during the evening and into the overnight hours. As they approach the provincial border and cross into Western Manitoba, the storms are expected to weaken and then dissipate in the early morning hours.

At their strongest, the severe thunderstorms today could easily produce large golf ball to tennis ball size hail, damaging wind gusts up to and possibly exceeding 100km/h, and heavy rain. There will be a widespread risk of tornadoes today in the area outlined in yellow and even in Southern Saskatchewan if storms are able to form there, but the most significant risk will be in the orange region. An area of particular concern today will be around North Battleford, Saskatoon, and Prince Alberta.

This is looking like it could be another long day with a heightened severe weather threat across the Prairies. Given today’s widespread tornado risk, please ensure that you have all of your devices charged and that you have more than one way to receive critical alerts. We expect to be livestreaming today’s storms so be sure to tune in!

Massive Tennis Ball Hail and Tornado Threat from Strong Severe Thunderstorms Across All Three Prairie Provinces Thursday

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Yesterday, two tornadoes have been confirmed to have touched near the Alberta-Saskatchewan border, south of Lloydminster. So far, no damage has been reported from the first tornado that began southwest of Paradise Valley, Alberta. The same can not be said for the second tornado, which tracked through Dillberry Lake Provincial Park, where it damaged trees, flipped a trailer, and caused minor injuries.

Unfortunately, this area will once again be at risk for tornadoes today, as we are looking at two particular regions in the Prairies where there could be strong severe thunderstorms capable of producing very large hail and tornadoes. The first area of concern will be in Southwestern Manitoba and extending northward into the Parkland and Interlake Regions. The second area is further west, extending southeastward from Wainwright, through Kindersley, to the Moose Jaw and Regina area.

To start things off, we’ll take a look at the severe risk in Eastern Saskatchewan and into Manitoba. As discussed in yesterday’s forecast, last night’s storms did manage to track across Saskatchewan overnight and persist through to the daylight hours today. They weakened considerably after crossing the Manitoba border and have gradually dissipated this morning.

Despite the lingering storms, the same low and frontal boundary setup that triggered yesterday’s tornadoes is positioned over Southern Saskatchewan and it will continue tracking eastward today.

Future Surface weather map with the positions of highs, lows, and fronts displayed for 12pm cst/1pm CDT on Thursday, courtesy of the national weather service.

Temperatures will climb into the mid-to-upper 20s and dewpoints into the low 20s across much of Southeastern Saskatchewan and Southern Manitoba today, meaning there will be plenty of moisture. The environment will also be quite unstable, with CAPE values possibly as high as 3000J/kg. Along with a decent amount of shear, all of the ingredients will be in place for strong severe thunderstorms to develop this afternoon as the low tracks through the region.

Thunderstorms could start to develop in the early afternoon in Southeastern Saskatchewan, along the warm and occluded fronts. However it’s looking more likely that storm initiation will occur on the other side of the Saskatchewan-Manitoba border in the mid-afternoon.

Simulated reflectivity at 3pm CdT, courtesy of weatherbell.

Given the extensive north-south orientation of the warm and occluded fronts, it’s possible that there could be widespread severe thunderstorm development that extends northwards from the international border to north of Flin Flon. While there is this large severe risk, the strongest severe thunderstorms are expected to remain further south.

The storms in Southern Manitoba are expected to strengthen quickly once they develop, especially if they interact with any lingering outflow boundaries from this mornings thunderstorms. If this were to happen, we could see some fairly explosive development in the region. There could be a few supercell storms, but it’s mostly looking like the storms will be multicellular in nature.

As the front slowly continues to track eastward and crosses Manitoba through the afternoon and evening, so too will the storms. In fact, these slow moving, moisture-laden storms could dump a lot of rain over an area that has already been dealing with major flooding issues, so be prepared.

Other than exacerbating the flooding concerns, if things really ramp up this afternoon and evening, the strong severe thunderstorms could potentially produce some massive hail today, with estimates of hail as large as tennis balls being possible. Damaging wind gusts up to 120km/h are also likely with these strong storms, and there will also be a threat of tornadoes if we end up seeing some of that explosive development.

The severe weather threat could possibly move into Winnipeg and the Red River Valley in the evening, but most models are showing the storms tracking southeastward into the States. The possibility of storms in this region is still a bit questionable, so we’re forecasting a widespread risk to the east of the area of strongest storms.

Simulated reflectivity, with added storm motion, at 7pm CdT, courtesy of weatherbell.

While storms are impacting Southern Manitoba, there will also be the risk of some severe thunderstorms further west.

A new low has been forming over Southern Alberta and it could trigger thunderstorms to develop this afternoon, but it’s looking like a boom or bust situation in this region. There will be plenty of moisture and a decent amount of instability, but there could actually be too much shear for thunderstorms to survive.

If storms are able to develop today and they aren’t over-sheared, they will likely be supercells that could start up in Central Alberta and track southeastward across West Central and Southwestern Saskatchewan. Models that are showing thunderstorm development are suggesting that these could end up being long-lived storms again, which could continue into the overnight and early morning hours as they approach the Montana border.

total Precipitation as of 3pm MDT/CST shows possible tracks of long-lived thunderstorms, courtesy of weatherbell.

The greatest risk of strong severe thunderstorms in Alberta and Western Saskatchewan today will exist from Wainwright to Moose Jaw and if these strong storms do develop, it could be a similar situation as yesterday. Very large hail, that could be tennis ball size or larger, would once again be the main severe threat. Damaging wind gusts well in excess of 100km/h will also be possible and there will be the threat of tornadoes, too.

Beyond the two areas we’ve highlighted as having the strongest severe thunderstorms today, there will also be a widespread severe risk across much of the Southern Prairies as a result of a favourable environmental conditions.

Shortly after 10:30am local time, Environment Canada has issued a Yellow Severe Thunderstorm Watch for parts of Central and Southern Alberta. Similar Watches will likely be issued in Saskatchewan and Manitoba in the coming hours.

As always, we will be monitoring today’s thunderstorm development very closely. We intend on live streaming today’s storms, as well as the risk in Southern Ontario, so please be sure to tune in and stay safe!

Severe Storm Risk Targets GTA and Southern Ontario Thursday With Damaging Winds Possible

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With the return of more seasonal temperatures across Southern Ontario, the past week has been fairly quiet on the storm front. That has certainly been a noticeable change compared to the nearly daily severe weather risks we were dealing with during the prolonged heat event that kicked off the month.

However, that quieter pattern is expected to come to an end on Thursday as a cold front sweeps across Southern Ontario during the afternoon, bringing back the threat for severe thunderstorms in some areas.

The highest risk for severe weather appears to be focused on Deep Southwestern Ontario, extending along the Lake Erie shoreline, through the Greater Toronto Area and along the Hwy 401 corridor into Kingston. This is where we have a widespread severe weather risk, with multiple severe storms possible through the afternoon.

Based on the latest data, a line of storms is likely to develop along the approaching cold front and move into an environment supportive of some of these storms becoming severe. The main threat appears to be damaging wind gusts, but large hail and localized flooding will also be possible with the strongest storms.

As for the tornado risk, it appears to be highest from around Lake Simcoe eastward into the Kingston area. However, this risk is still fairly questionable and will depend on how storms develop and interact with the local environment.

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The main timeframe for storm development appears to begin during the early afternoon, with storms likely stretching from Lake Simcoe through Kitchener, London and into the Sarnia area between 1 and 4 PM.

These storms are expected to slowly track south and east through the afternoon, potentially moving into the Golden Horseshoe, Peterborough and Kingston area by the mid to late afternoon.

Keep in mind, not everyone will see severe storms. This is not expected to be a solid wall of storms affecting every community. Instead, storms will likely be somewhat isolated to scattered, but the environment in place means that any storm that does develop could become severe.

The storm risk should quickly diminish after the dinner hour as daytime heating fades and the front moves through. However, this will depend on the exact timing of the front. If it arrives a little later than expected, the severe risk may continue into the early evening hours for some areas.

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Based on the environment, we have gone with a ‘widespread’ severe weather risk, mainly driven by the potential for damaging wind gusts. Nickel to quarter-size hail and an isolated tornado are also possible.

This risk zone includes Windsor, Chatham, Sarnia, London, Hamilton, Niagara Falls, Kitchener, Guelph, Toronto, Newmarket, Peterborough, Belleville, Kingston and Brockville.

We also have an isolated severe risk for the rest of Southwestern Ontario, through Central Ontario and into the Ottawa Valley. This includes Ottawa, Cornwall, Renfrew, Bancroft, Muskoka, Orillia, Barrie, Midland, Collingwood, Orangeville, Hanover, Kincardine and Goderich.

Storms in this zone are more likely to remain non-severe, but we can’t rule out one or two isolated severe storms. This is especially true if the front is slower than expected, which could allow stronger storms to develop farther north and west before tracking into the main risk zone.

Threat of Tennis Ball Hail, Damaging Winds, and Tornadoes on Wednesday as Strong Severe Thunderstorms Take Aim at Parts of Alberta & Saskatchewan

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After a bit of a break yesterday, severe weather returns today to parts of Alberta and Saskatchewan. There is a widespread risk of severe thunderstorms across large swaths of both provinces today, however there is a threat of particularly strong severe thunderstorms for parts of Eastern Alberta and Western Saskatchewan.

The environment will be quite unstable throughout the region today, with CAPE values expected to climb as high as 2500J/kg. Combined with plenty of moisture and a considerable amount of shear, conditions will be favourable for thunderstorm development.

Some storms have already begun this morning to the northwest of Lac la Biche, and the bulk of today’s storms are expected to initiate in the Alberta Foothills later this morning and into the early afternoon. The storms will develop along a warm front that’s associated with a low which will move into Northern Alberta from British Columbia. It’s expected that today’s thunderstorms will start off as small individual storms, but they should quickly grow and strengthen as the track eastward across Alberta and reach the Saskatchewan border by the late afternoon.

Hourly Precipitation at 6pm MDT, courtesy of weatherbell.

The strongest storms of the day are expected to occur during the late afternoon and into the evening, impacting parts of Eastern Alberta approaching the Saskatchewan border and extending eastward as far as Saskatoon. The main risks from these storms will be up to tennis ball sized hail and very damaging wind gusts that could be upwards of 120km/h, however, this area will also have the threat of tornadoes.

As we progress later into the evening and overnight, the storms will continue to track east across Saskatchewan, but they are expected to have weakened slightly. The thunderstorms could end up persisting straight through the night and approach the Manitoba border around sunrise tomorrow.

Simulated reflectivity at 6Am CST, courtesy of weatherbell.

There is a bit of uncertainty associated with today’s thunderstorm risk for Southern Alberta. A few weather models are showing little to no thunderstorm activity in this area and this potential lack of development could be due to the presence of smoke from wildfires in British Columbia. Regardless, the environment in this region will still be primed for thunderstorm development, which is why we have opted to forecast a widespread risk for this region.

Environment Canada has already issued Yellow and Orange level Severe Thunderstorm Watches for much of Central and Southern Alberta and these will likely be extended into Saskatchewan in the coming hours. We will be monitoring today’s thunderstorm development very closely and we will possibly go live later on so be sure to stay tuned!

Widespread Strong Severe Thunderstorm Risk Across the Prairies Sunday with Tornado Threat in Southwestern Manitoba

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It’s another day with the possibility of severe weather across the Prairies. Today’s risk extends eastward from Southern Alberta through Central Saskatchewan and throughout most of Central and Southern Manitoba.

There are going to be two areas where we will be watching for thunderstorm development later today. The first being in Southern Alberta and the second in Southeastern Saskatchewan and Southwestern Manitoba.

Starting in Alberta, the combination of heat and moisture from the south, along with considerable instability, will create the ideal environment for severe thunderstorms to develop this afternoon. The storms are expected to be supercells or multicellular that would develop in the Southern Foothills.

As the storms track eastward beyond the Foothills, they should become severe and possibly long-tracked thunderstorms. Looking at weather models, it appears as though things will strengthen to the east of Calgary, but there will still be an isolated severe risk for the City and the crowds at the Stampede.

Simulated reflectivity at 6pm MDT, courtesy of weatherbell.

The thunderstorms that develop in Southern Alberta this afternoon could very well maintain their strength and continue tracking eastward straight across Central Saskatchewan through the late evening and into the overnight hours. There is a bit of a question mark with this, with some models showing this possibility while others show nothing impacting Saskatchewan.

Regardless, the thunderstorms that do end up developing in this region could be quite strong and have the potential to create very large hail that could possibly be as big as tennis balls, as well as damaging wind gusts in excess of 100km/h.

The secondary area of severe threat for today will exist in Southeastern Saskatchewan and across much of Southern and Central Manitoba.

The development of storms in this region will be courtesy of a cold front from a low pressure system that will move into the region this afternoon. The environment in this area will already be primed with substantial instability (CAPE values upwards of 3000J/kg) and a significant amount of vertical shear so thunderstorms will likely be quite strong, especially in Southwestern Manitoba.

Thunderstorm development in this part of the Prairies could kick off later this afternoon/early evening in deep Southeastern Saskatchewan and Southwestern Manitoba. These storms could then intensify quickly as they track east-northeastward across Southern Manitoba throughout the evening and overnight.

Simulated reflectivity at 9pm CDT, courtesy of weatherbell.

As with to the west, the severe thunderstorms that impact Southeastern Saskatchewan and Manitoba could also be quite strong. The entire region could experience large hail and damaging wind gusts, but in Southwestern Manitoba, where the strongest storms will likely hit, there could be hail as large as tennis balls. There is also the risk of tornado development throughout the evening that extends from Southeastern Saskatchewan to east of Winnipeg and northward into the Parkland and Interlake Regions.

We will be monitoring today’s thunderstorm development very closely and be sure to tune in later when we go live!

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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