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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

STAY AHEAD OF THE STORM

Join us on YouTube as we track any storms that develop on Thursday. Make sure to hit the free Subscribe button and the notification bell icon to get notified when we go live!

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

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

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

📍 Location A: Portions of Southern & Northeastern Ontario

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

Impacts:

• 🪁 Loose objects may be tossed

• 🏚️ Damage to weak buildings

• 🌳 Broken tree branches and downed trees

• 🌿 Possible damage to plants and crops

• 🌊 Flash flooding and pooling on roads

• ⚡ Power outages likely

Rainfall: Up to 50 mm

Confidence: Moderate
Impact: Moderate

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

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

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

Impacts:

• 🌳 Broken tree branches and downed trees

• 🌊 Flash flooding and pooling on roads

• ⚡ Possible power outages

Rainfall: Up to 50 mm

Confidence: Moderate
Impact: Moderate

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

---

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

---

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

Here’s some more details on Kempenfest:

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

We hope to see you there!

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

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

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

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

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

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

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

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

The dashed line outlines the funnel cloud risk from environment Canada

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

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

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

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

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

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

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

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

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

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

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

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

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

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

The dashed line outlines the funnel cloud risk from environment Canada

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

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

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

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

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

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

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

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

STAY AHEAD OF THE STORM

Join us on YouTube as we track any storms that develop throughout the day on Thursday

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

ESTIMATED TEMPERATURE in °C - MAP FROM WEATHERBELL

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

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

SIMULATED RADAR - MAP FROM WEATHERBELL

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

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

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

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

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

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

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

ESTIMATED Morning LOW in °C - MAP FROM WEATHERBELL

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

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

ESTIMATED DAYTIME HIGH in °C - MAP FROM WEATHERBELL

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Risk of Timbit-Sized Hail from Severe Thunderstorms Across Parts of Alberta for Canada Day

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

There could be some natural fireworks in parts of Alberta today for Canada Day!

Thunderstorms are likely to develop along the Foothills early this afternoon, around 12-2pm, which are expected to travel northeastward across the region throughout the afternoon and evening. However, some storms could end up following a more eastward trajectory through the day as they interact with the ridge which has been drawing some heat into Southern and Central Alberta.

Severe storms will possibly develop into multicellular clusters that could impact a wide area, but some isolated supercells are also probable. Large hail is the greatest risk from today’s storms, up to the size of Timbits or possibly larger, along with some strong wind gusts. Thunderstorms are expected to weaken in the late evening hours, with a majority of storms dissipating by midnight.

More Severe Thunderstorms Likely Across Central & Southern Manitoba Saturday

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

After some severe thunderstorms and tornado warnings yesterday, we’re looking a similar setup as yesterday. A trough will continue moving through the province and it is expected to trigger more severe thunderstorms today.

Severe thunderstorms have already begun to move through the Interlake Region this morning, which are expected to continue to strengthen as they travel eastward. The greatest severe thunderstorm threat, however, looks to start in the early to mid afternoon and continue into tonight.

The afternoon storms could develop across a large swath of Central and Southern Manitoba. However, there has been disagreement between weather models regarding where exactly these storms could occur and how strong they might become.

Some models are showing that storms could begin developing in the early afternoon through the Parkland Region and southward, into parts of Westman and to the west of the Red River Valley. The timing of the storm initiation in the south is also a bit uncertain, with models suggesting it could occur sometime between 1pm and 5pm. There is also the likelihood of additional storms crossing into the Parkland area from Saskatchewan in the early evening.

Simulated Radar from the NAM model showing the possible line of thunderstorms moving through the Red River Valley at 5PM CT, Courtesy of Weatherbell.

The storms that manage to form are expected to rapidly gain strength as they chart a course eastward across the province. They are likely to become supercells and could end up merging into a large line of severe thunderstorms through the afternoon.

These intense thunderstorms will have the potential to produce golf ball or larger hail, damaging wind gusts in excess of 100km/h, and possibly a tornado. The risk of a tornado is less than yesterday, but the possibility can not be completely ruled out. These are expected to be moisture-laden and slow-moving thunderstorms, so localized flooding is definitely a concern as well.

Thunderstorm activity will gradually dissipate through the late evening hours as they approach and cross into Ontario. The severe thunderstorm threat is expected to conclude across Manitoba by midnight.

Severe Weather Threat Extends Across the Prairies Friday with Strong Risk and Tornadoes Possible in Parts of Saskatchewan & Manitoba

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

It’s shaping up to be an active day across the Prairies today, with severe thunderstorms possible across all three provinces. In fact, today brings the strongest severe weather risk we’ve seen all week.

Most of the thunderstorms expected across the region will likely remain marginally severe, stretching from the Foothills in Alberta to the Manitoba-Ontario border. However, the bullseye for the most intense storms is over Southeastern Saskatchewan and Southwestern Manitoba.

Thunderstorms are expected to kick off in parts of the Southern Foothills early this afternoon. These storms will track east-northeastward, and additional development is likely through the mid-afternoon along a broad arc stretching eastward across Central Saskatchewan and into Central Manitoba later in the evening.

These widespread storms should persist into the night across the Prairies, especially the further east you go. Some of these storms could become severe and produce nickel-sized hail, along with strong wind gusts. There is also a risk of localized flooding due to heavy rain from slow-moving or training thunderstorms.

In Alberta, conditions could be favourable for funnel clouds to form. While most of these remain harmless, there is a low chance that one or two could touch down briefly as a weak landspout tornado.

Simulated Radar from the HRRR model showing the arc of thunderstorms at 6pm MT/CST & 7PM CT, Courtesy of Weatherbell.

The greatest threat for severe weather today, however, will be to the south of the main batch of storms in Sakatchewan and Manitoba. The model image above shows these additional storms having already developed in the evening. Thunderstorm development in this more volatile area is expected to begin slightly earlier, around 3-5pm. Storms in this region will track eastward, while the southern edge of the cluster in Saskatchewan will likely expand south-southwestward toward the US border.

This area is forecast to encounter a highly supportive environment for severe storms in Southeastern Saskatchewan, with the possibility of storms to rapidly develop into supercell thunderstorms. Some isolated supercells could also initiate within this environment, along the Saskatchewan-Manitoba and into Southwestern Manitoba.

The highest risk area stretches from Carlyle, SK eastward through Brandon, MB, and north from the US border to the Foxwarren radar site. Storms moving through this area could become quite strong, with the potential to produce golf ball or larger hail, damaging wind gusts in excess of 100km/h, and possibly one or two tornadoes. Intense rainfall is also likely, making localized flooding a concern in this region as well.

Simulated Radar from the HRRR model showing thunderstorms in North Dakota, as well as in Saskatchewan & Manitoba at 9pm CST & 10PM CT, Courtesy of Weatherbell.

There are a couple of factors that might limit storm strength in this region. Lingering morning rain and cloud cover could reduce daytime heating, which would decrease the available energy for storm development. Additionally, an area of low-pressure that will track through North Dakota today may pull some of that energy south of the border, weakening the storms on the Canadian side.

Regardless of how strong the storms become, they are expected to track eastward throughout the evening and into the overnight hours. By the time they reach the Red River Valley after midnight, the storms should be quite weak and likely dissipate entirely not too long after.

Southern Ontario Faces Widespread Severe Threat Including Damaging Wind Gusts, Toonie-Sized Hail & Tornado Risk on Friday

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

After Southern Ontario experienced some severe weather last weekend along with our first significant heat wave of the season, things have quieted down over the past few days. Milder air brought temperatures back to seasonal values on Wednesday and Thursday.

However, it looks like we’re about to heat up again heading into the weekend. The good news is, it won’t be anywhere near the oppressive heat we saw earlier this week.

In addition to the return of summer warmth, there’s a growing risk of widespread severe storms on Friday. This threat covers much of Southwestern Ontario and stretches into parts of Central Ontario and the Golden Horseshoe.

Isolated thunderstorms are expected to fire up over Lake Huron and move into a very unstable environment during the afternoon, leading to the possibility of all severe weather hazards. This includes damaging wind gusts, large hail and potentially even one or two tornadoes.

As these storms push eastward into the evening hours, there’s a chance they could merge into one larger cluster of storms. This line may reach portions of the Greater Toronto Area and bring a continued threat of damaging winds, small hail and localized flash flooding.

ESTIMATED DAYTIME HIGH in °C - MAP FROM WEATHERBELL

While the heat has pulled back across much of Southern Ontario over the past few days (except for Deep Southwestern Ontario), we’re expecting it to return on Friday. Areas south of Lake Simcoe will likely see daytime highs climb back into the upper 20s and even low to mid-30s across parts of Southwestern Ontario.

This won’t be the same level of heat we saw earlier in the week, but it will be a noticeable jump compared to the cooler air on Thursday that kept many places under 20°C for most of the day.

Once you factor in the humidity, some parts of Deep Southwestern Ontario could be feeling close to the upper 30s again.

SIMULATED RADAR - MAP FROM WEATHERBELL

As we often see on days with elevated storm risk, the morning could bring some scattered showers or thunderstorms near Lake Huron and Georgian Bay. These are not expected to be severe, but they will play an important role in shaping the setup for later in the day.

If the morning rain and storms linger longer than expected, they could limit afternoon storm development by preventing the atmosphere from fully recovering. This could reduce the strength or delay the timing of any severe storms into the evening when conditions aren’t quite as favourable.

There’s also some disagreement in the forecast models about how far south this morning precipitation might extend, especially in the zone where the severe risk is currently expected to be the highest.

SIMULATED RADAR - MAP FROM WEATHERBELL

If the atmosphere is able to recover in time, we could see isolated storms begin to fire over Lake Huron as early as mid-afternoon (2 to 4 PM), then track inland toward Grey, Bruce and Huron counties.

There’s still some uncertainty on the exact placement of this development. Storms could form anywhere along a corridor stretching from Manitoulin Island all the way down to Sarnia.

ESTIMATED ENVIRONMENT FOR TORNADOES - MAP FROM WEATHERBELL

As these cells develop over Lake Huron, they’ll be moving into a rapidly strengthening environment. Current model data suggests the highest tornado potential may be from Goderich to Owen Sound around 3-5 PM.

This region could see the greatest risk for severe weather during the mid to late afternoon hours. Storms that remain isolated early on may evolve into supercells capable of producing damaging wind gusts, large hail and a tornado or two.

While this particular setup leans more toward Southwestern Ontario, other models point to a similarly strong environment farther northeast into Central Ontario. This includes areas around Lake Simcoe, as well as parts of Simcoe County, Muskoka and the Kawartha Lakes.

SIMULATED RADAR - MAP FROM WEATHERBELL

As the storms push eastward during the late afternoon, current data suggests they may merge into one larger cluster of storms by the time they reach Central Ontario and then move into the Greater Toronto Area during the early evening.

At that point, the tornado threat will decrease, but the risk of damaging winds will become the dominant threat. This is typical when storms evolve into more linear systems.

Flash flooding could also become a major concern, especially in urban areas like the GTA, which are more prone to poor drainage. Some forecast models even suggest that this line could stall or ‘train’ over the same area, which would bring the potential for very heavy rainfall in a short amount of time.

The overall severe threat should begin to wind down between 9 and 10 PM as the sun sets and daytime heating fades. That said, the storm cluster may continue eastward into the Niagara Region and parts of Eastern Ontario overnight, though it’s expected to be non-severe by then.

As mentioned, the highest severe threat will likely be in the mid to late afternoon over Southwestern Ontario, especially as storms come ashore from Lake Huron.

These storms could bring damaging wind gusts, hail up to the size of toonies and possibly one or two tornadoes. The tornado risk would be greatest shortly after the storms reach land and should taper off farther inland.

Deep Southwestern Ontario might also see a few isolated storms develop during the afternoon, though the environment doesn’t look quite as favourable compared to areas farther north.

Still, any storms that do form here could bring isolated damaging wind gusts, quarter-sized hail and even a low-end tornado risk that can’t be ruled out.

As the storms move into Central Ontario later in the day, the primary risk will transition to damaging winds. The threat of hail and tornadoes will decrease, but a few storms could still produce quarter-sized hail and, again, an isolated tornado remains possible.

There’s also the potential for some isolated development around Georgian Bay and Lake Simcoe in the afternoon. If that happens, it could boost the tornado and hail risk across that region.

By the time the line of storms reaches the Golden Horseshoe, it will likely be starting to weaken. However, it could still bring the potential for isolated wind damage, nickel-sized hail and maybe a brief tornado, though that risk becomes increasingly unlikely at that point.

Risk for Severe Thunderstorms Continues in Saskatchewan Thursday Along with Torndao Threat

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

The same low pressure system and warm front that triggered the development of severe storms and multiple tornado warnings yesterday will continue to impact parts of Saskatchewan today. The same severe thunderstorm risk also exists today, but the difference is that there is now a secondary area of low pressure that has built up along the preexisting warm front and a cold front is trailing not too far behind. This means that today’s severe thunderstorm threat is further east than yesterday, and it does not extend quite as far northward.

Despite this, thunderstorms are still expected to once again develop along the length of the warm front, stretching approximately from Saskatoon through Regina and into the US, as the front continues to cross the province today. As with yesterday’s setup, it is looking likely that the thunderstorms today will start off as isolated cells in the mid to late afternoon, around 2-4pm, with a majority of them then merging into northeastward travelling multicellular lines later in the afternoon and through the evening.

The thunderstorms are anticipated to quickly surpass the severe threshold in the late afternoon, with the greatest severe threat expected in the early evening. Today’s severe thunderstorms, much like yesterday, will have the potential to create large hail, which could be as large as golf balls, damaging wind gusts up to 110km/h, and possibly an embedded tornado. At this point, it appears that the tornado risk is lower than yesterday, but the potential still exists. Environment Canada has highlighted around Regina and areas to the northeast, in particular, as a region where the strongest of today’s severe thunderstorms could impact.

Today’s storms are expected to weaken later in the evening, but there is a chance that they could remain severe as they continue tracking northeastward into Manitoba overnight. Futhermore, there could be some stray thunderstorms that develop a bit further west, behind the main line, throughout the evening. These storms will likely be weaker, with the preceding storms taking a lot of energy out of the environment. Nevertheless, they will have the potential to become severe, especially as the storms ahead of them lose strength.

Widespread Risk of Severe Thunderstorms for Saskatchewan & Alberta Wednesday with the Risk of a Tornado

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

A widespread risk of severe thunderstorms returns to Saskatchewan today with the arrival of a low pressure system that will track through the region. A warm front that will extend from the low is expected to trigger severe thunderstorms beginning this afternoon and continuing into overnight. The greatest risk for severe storms stretches from parts of Central Alberta through a large swatch of Central and Southern Saskatchewan, but there is also a chance for thunderstorms developing in the Foothills, which could become severe.

Thunderstorm development in the Foothills is expected to begin shortly after the lunch hour as isolated cells with further development possible throughout the afternoon and into the late evening. These isolated storms could have the potential to strengthen into severe supercell thunderstorms as they travel east-northeastward. The QE2 corridor between Red Deer and Calgary, in particular, could end up seeing some severe thunderstorms throughout the afternoon and evening, with the possibility of toonie-sized hail and wind gusts up to 90km/h.

Simulated Radar from the HRRR model showing 6pm CST, Courtesy of Weatherbell.

The thunderstorms further east, on the other hand, have a much greater chance of becoming severe, along with greater overall threats. As the warm front moves through the region, it is anticipated to trigger the development of severe thunderstorms along its entire length. This could begin as early as around noon, with storms continuing straight through into the overnight hours as the front tracks northeastward across Saskatchewan. The thunderstorms are expected to weaken later in the evening in the eastern half of the province, but there is the chance that the odd storm could maintain severe strength overnight.

One specific area that we will be monitoring will be along the Alberta border north to the Lloydminster and North Battleford area and from there, southeast to Regina. This is where the strongest of the storms will likely occur, which could possibly develop hail as large as golf balls, wind gusts in excess of 100km/h and potentially a tornado or two.

Isolated Severe Thunderstorms Could Hit Parts of Alberta Tuesday with Possible Timbit-Sized Hail & Strong Winds

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

Isolated thunderstorms are possible across parts of Southern and Central Alberta today. A majority of these storms are expected to be non-severe, but there is chance for severe storms to develop through the QE2 corridor, from Red Deer to almost Cardston. The storms will likely form into multicell clusters, but there is the possibility of a supercell or two developing.

Thunderstorm activity is expected to start in the late afternoon, around 3-5pm, through the Foothills. The storms could become severe for the remainder of the afternoon and into the evening, as they make their way eastward, especially in the aforementioned corridor to the south of Red Deer. As we get closer to midnight, the thunderstorms are expected to gradually weaken and become sub-severe as they continue towards Saskatchewan overnight.

The main risks from today’s thunderstorms, if they do end up becoming severe, are hail that could be as large as Timbits and strong wind gusts up to 90km/h. Furthermore, the chance of a tornado forming from these storms is low, but can not be ruled out in the event of supercell thunderstorms developing.

Simulated Radar from the HRRR model showing 8pm MT, Courtesy of Weatherbell.

Severe Thunderstorms Possible in Parts of Manitoba Tuesday with Risk of Large Hail & Strong Winds

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

Scattered severe thunderstorms are possible across parts of Southern and Central Manitoba today as a low pressure system moves through the region. Daytime heating will build the energy for these storms and for them to likely become severe beginning later in the afternoon and into the evening.

Thunderstorm activity is expected to start in the late afternoon, around 3-5pm, particularly in the North Eastman region, but also in Eastman. The storms will likely become severe and will persist for a few hours in the region as they travel eastward into Ontario.

Simulated Radar from the HRRR model showing 7pm CT and storms missing Winnipeg, Courtesy of Weatherbell.

There is some disagreement between short-term weather models, but it is possible that severe thunderstorms could also develop stretching southwestward into the Red River Valley at roughly the same time. On the other hand, this development could end up beginning slightly later, around 6pm. In the second scenario, it’s possible that storms could form closer to the US border, resulting in Winnipeg getting missed by the severe weather.

The main risks from today’s severe thunderstorms are hail that could be as large as ping pong balls and strong wind gusts up to 90km/h. The chance of a tornado forming from these storms is low.

Southern Ontario to Kick Off Summer This Weekend With Significant Severe Risk and Tornado Threat on Saturday; Sizzling Heat Near 40°C on Sunday

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

Summer officially arrived late Friday night with the summer solstice, and it looks like Mother Nature isn’t wasting any time making it feel like summer across Southern Ontario. A multi-day heat wave is on the way, bringing the potential for record-breaking temperatures starting Sunday and continuing into early next week.

But before the heat sets in, we’re looking at what could easily be our strongest and most widespread severe weather threat of the season so far on Saturday. There are a lot of factors at play that make this a classic ‘boom or bust’ setup, which we’ll break down below.

There’s high confidence in a potent storm environment stretching across much of Southern Ontario. The big wildcard, however, is whether storms will actually develop to take advantage of all that energy. If they do, they could bring very large hail, destructive wind gusts, and possibly even a couple of tornadoes.

What’s especially concerning is that the storm environment doesn’t fade away after sunset like it typically does. In fact, it remains quite strong through the overnight and into Sunday morning, which could support a nocturnal line of storms with widespread damaging wind potential.

Once the severe risk passes, intense heat begins to build. Temperatures will soar well into the 30s by Sunday, with humidex values making it feel closer to the 40s. The heat continues Monday and Tuesday, with some relief expected midweek. That said, it’ll likely stay warm into the end of June and possibly early July.

A key ingredient in Saturday’s severe weather threat is already unfolding over North Dakota early Saturday morning. An intense line of storms, known as a “derecho” (a fast-moving complex of severe thunderstorms that can produce widespread wind damage), is sweeping through the northern Plains.

This system is producing destructive wind gusts of over 150 km/h along with several tornadoes and has already left damage in its wake. It’s expected to continue tracking eastward into the Great Lakes region through the day.

SIMULATED RADAR - MAP FROM WEATHERBELL

So what does that mean for Southern Ontario?

Derechos are known to travel long distances, and current model guidance suggests this one could follow a path toward Northeastern Ontario. Areas near the U.S. border, including Sault Ste. Marie and Elliot Lake, could be affected by the remnants of this system Sunday morning.

There’s still some uncertainty around how strong the system will be by the time it reaches Ontario. Forecast models often struggle with capturing the evolution and intensity of derechos, so the possibility that this one is being underestimated shouldn’t be ignored.

SIMULATED RADAR - MAP FROM WEATHERBELL

The projected track of what’s left of this potentially decaying derecho places it crossing Lake Huron and Georgian Bay into Central Ontario sometime Saturday afternoon.

If it maintains strength, it could bring damaging wind gusts, hail up to the size of toonies and maybe even an isolated tornado. But this could just be the first of multiple storm rounds.

Some models are also hinting at additional isolated storm development around Elliot Lake and Sudbury in the wake of the earlier line. That suggests the atmosphere could quickly recharge, although it’s still unclear how widespread any new storms would be.

ESTIMATED ENVIRONMENT FOR TORNADOES - MAP FROM WEATHERBELL

As we move into the late afternoon and evening hours on Saturday, the storm environment really ramps up. One of the key indicators we look at, the Significant Tornado Parameter, is literally off the charts in some areas, particularly near the Lake Huron shoreline and into Georgian Bay.

Here’s the catch, though: storms need to develop in this environment to take advantage of it. If they do, they could rapidly become severe, with the potential for all hazards. That includes large hail (possibly golf ball-sized or bigger), destructive winds over 100 km/h, and tornadoes.

SIMULATED RADAR - MAP FROM WEATHERBELL

Looking at what one model is simulating, there’s a notable lack of storms in the highest risk areas around Lake Huron. Instead, storms appear to fire up along a line from Sudbury to Parry Sound through Muskoka, just northeast of the most primed environment. These storms could still be strong and bring similar hazards.

It’s worth noting that models may be underdoing storm development in Southwestern Ontario. That’s something we’ll need to monitor in real time. If nothing happens in Southwestern Ontario, it could end up being a ‘bust’ - which would be good news for those who aren’t fans of severe storms.

ESTIMATED ENVIRONMENT FOR TORNADOES - MAP FROM WEATHERBELL

Typically, severe weather threats wind down after sunset as daytime heating fades. But in this case, models are suggesting the environment will remain unusually supportive of storm activity well into the overnight hours and early Sunday.

There’s even the potential that a new line of storms forms north of Georgian Bay and sweeps southeast through Southern Ontario overnight. If this happens, it could evolve into another derecho-type system - similar to the one seen Friday night in North Dakota.

Forecasting derechos is notoriously difficult, as models often fail to capture their full strength and endurance. While nothing is certain, this setup definitely has the ingredients to support a nocturnal derecho-type event.

If this scenario plays out, we could see widespread wind damage across Central and Eastern Ontario, possibly extending into parts of Southwestern Ontario and the Golden Horseshoe.

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

This is a very tricky forecast, and while we've gone with a ‘significant’ (level 4 out of 5) risk, that doesn’t mean everyone will see storms. The risk will come in waves, and some areas may be completely missed.

That said, the potential severity of any storms that do form justifies this level of concern. We’re talking about the possibility of golf ball-sized hail or larger, destructive wind gusts (possibly from a derecho), and a few tornadoes. The tornado risk will largely depend on storm structure—more linear setups will favour damaging wind, while discrete supercells could increase the tornado threat.

The highest severe risk covers areas around Georgian Bay including Sault Ste. Marie, Elliot Lake, Manitoulin Island, Britt, and into Central Ontario such as Muskoka, Simcoe County and Bancroft.

A broader ‘strong’ risk zone includes much of Central and Eastern Ontario, the northern portions of Southwestern Ontario, and the Greater Toronto Area.

Meanwhile, areas like London, Kitchener, Hamilton and the Niagara region fall into the widespread severe risk category.

For once, Deep Southwestern Ontario may dodge the worst of the storms. Windsor, Chatham and Sarnia are currently in the isolated severe risk zone. While a stray storm can’t be ruled out, most of that region looks to stay quiet Saturday.

There may be another round of severe weather on Sunday afternoon and evening, but confidence in the details is still low. Eastern Ontario may be favoured, but we’ll refine that forecast once Saturday plays out.

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

Sunday marks the beginning of an extended stretch of dangerously hot temperatures. The most intense heat is expected across Deep Southwestern Ontario into the Golden Horseshoe.

Areas like Windsor, Sarnia, London, Hamilton, Kitchener and Toronto could see daytime highs between 35°C and 40°C. With humidity, it will feel like the mid-40s in many spots.

Locations near Lake Ontario, Lake Erie, Lake Huron and Georgian Bay will be 5 to 10 degrees cooler, but it doesn’t take much distance inland to hit the oppressive heat.

Elsewhere in Southern Ontario, expect highs in the low to mid-30s with humidex values near 40°C.

Heat Safety Tips:

• Stay hydrated and avoid strenuous outdoor activity during peak heat hours.

• Check in on vulnerable individuals, including the elderly, young children and those with health conditions.

• Never leave pets or people in parked vehicles.

• Use fans or air conditioning when possible and find shade or cooling centres if needed.

SOURCE: ECCC

There’s a good chance many locations will break temperature records going as far back as the 1800s over the next few days.

According to Environment Canada, record highs in cities like Toronto, Windsor, Ottawa, London and Hamilton are in the mid to upper 30s for Sunday, Monday and Tuesday. Based on the current forecast, some of these records may fall.

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

Monday brings more of the same, with extreme heat expanding into parts of Central and Eastern Ontario in addition to Southwestern Ontario and the GTA.

Once again, humidex values will push into the 40s, making it feel extremely uncomfortable and even dangerous for some.

Tuesday will still be hot, but may be slightly cooler compared to Monday. Some relief is on the way by Wednesday, although temperatures will likely stay warm overall.