Possibility for Severe Weather Continues for Alberta with Isolated Severe Thunderstorms Bringing Heavy Rain, Strong Winds, and Hail on Monday

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Our stretch of active weather continues today with the risk of some isolated severe storms this afternoon and evening across Alberta. We are not looking at a situation where storms are large and widespread, but rather, a large area could see the odd pop-up thunderstorm today.

The storms are expected to develop early this afternoon, around 12-2pm, in Central and parts of Northern Alberta, mostly from Edmonton and northward. The likelihood of development increases eastward and a greater number of small storms are expected in the eastern half of the region.

The severe threat diminishes to the north of Slave Lake and Lac La Biche, so those northward of these areas can expect non-severe thunderstorms or heavy rain showers throughout the day. The threat also diminishes later into the evening so severe thunderstorms that develop this afternoon and evening will eventually become sub-severe as they track southeastward.

A bit later in the afternoon, beginning around 3-5pm, additional isolated thunderstorms are expected to develop east of the Rockies. These storms are also expected to be isolated as they progress eastward through the remainder of the afternoon and into the evening. They should lose a majority of their energy later in the evening, leading to some scattered showers continuing in some parts of Central and Southern Alberta overnight.

The thunderstorms today, while likely becoming severe, are not anticipated to be as severe as the storms we’ve seen in Alberta over the past couple of days. Nonetheless, these severe storms will have the potential to deliver heavy downpours with localized flooding, strong wind gusts of up to 90km/h, and fairly large hail which could be as large as your standard Timbit. The environment does not appear to be conducive to the development of funnel clouds or tornadoes today, but a touch down can never be completely ruled out with severe weather.

Stronger Risk for Severe Thunderstorms for Friday in Alberta & Saskatchewan Which Could Bring Damaging Winds, Large Hail, and Possibly a Tornado

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While yesterday’s storms didn’t quite cross the threshold of becoming severe, the chances for severe thunderstorms are much greater for today, as a low pressure system moves through Central Alberta. Areas north of the low, into Northern Alberta, can expect widespread rain today as the system tracks eastward, with up to 20mm falling, and an additional 20mm is possible on the backside of the system through the day tomorrow. Around the low and southward, however, severe thunderstorms are expected to dominate the afternoon and continue into the evening and overnight hours.

Isolated thunderstorms could start to develop as early as the noon hour, but the bulk of the storms are anticipated to begin in the mid-afternoon, around 2-3pm, and continue into the evening across Central and Southern Alberta as the low and its associated warm front cross through the region. The storms triggered by this front are expected to be isolated, with the environment favourable for the development of supercells, so the activity won’t be as widespread as seen yesterday.

A bit later in the afternoon, there is also a slightly higher chance that storms in Southeastern Alberta could become severe as they cross into Saskatchewan. This will be dependent on the southerly winds clearing wildfire smoke out of the area so that daytime heating can be maximized ahead of the warm front. Storm activity could continue overnight through parts of Saskatchewan, but they are expected to quickly lose strength later in the evening so any remaining storms should be sub-severe.

Today’s severe thunderstorms could bring damaging wind gusts up to, and possibly exceeding, 100km/h, along with heavy downpours and hail as large as ping pong balls. In the East-Central region of Alberta, from Edmonton towards Lloydminster and southward to almost Red Deer, the environment will also be favourable for the development of funnel clouds and there is a slight chance of a tornado forming.

Fire danger map for June 12th produced by the government of Alberta

There has been a major decline in the fire hazard across most of Central and Southern Alberta with widespread rain over the past couple of days. That trend will continue into parts of Northern Alberta with the significant rain that is expected to fall to the north and on the backside of the low pressure system that will track across the province today.

The storms that could to move into Southwestern Saskatchewan later today may also start to lead to a downtrend in the fire danger in that area. We could possibly see this trend continue tomorrow as the system is expected to cross through Saskatchewan, bringing additional thunderstorm activity to the southern half of the province and widespread rain to the north of the low.

Isolated Risk for Severe Thunderstorms Thursday with Damaging Wind Gusts and Hail Possible

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After an extended period of dry conditions across Southern Alberta, aside from the odd pop-up shower or non-severe thunderstorm, we’re finally seeing that pattern change. More widespread rain finally returned to the region yesterday, which has continued into this morning. This afternoon, we can also expect to see the return of severe thunderstorms.

Thunderstorm activity is expected to kick off in the early afternoon, around 12-2pm, in the Foothills and northward, to the east of the Rockies. These storms will start off as isolated cells, but they could merge into larger clusters of storms as they gradually track northeastward through the afternoon.

Additional storms will follow in the evening, extending further south towards the US border. These storms could maintain their strength, if conditions remain favourable, as they end up tracking eastward across Southern Alberta overnight and into tomorrow morning. Otherwise, the region could just experience some moderate to heavy rainfall instead.

The greatest thunderstorm risk will be in the Southwest, stretching from Calgary southward to the US border and east through Taber. This region could see damaging wind gusts of up to 100km/h and large nickel to quarter-sized hail, along with torrential downpours. At this point, the threat of a tornado appears to be unlikely, but it can not be completely ruled out.

Fire danger map for June 12th produced by the government of Alberta

With the return of some rain, we’re also seeing a downtrend in the fire danger in Central and Southern Alberta. The arrival of more rain today, despite the presence of some lightning, will likely lead a continued decrease in the fire danger in Southern Alberta. The lightning could still spark additional fires in areas where the fire danger remains elevated so it’s important to watch for any new fire activity and to report it immediately if you see smoke.

Southern Ontario Faces Another Round of Wildfire Smoke and Unhealthy Air This Week

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Southern Ontario continues to deal with lingering wildfire smoke from fires burning across the Prairies and Northern Ontario. While the thickest smoke has cleared out of the region for now, Thursday and Friday brought some of the worst air quality readings we've seen since at least 2023, with several areas reaching unhealthy levels.

As of Sunday evening, there’s still some smoke in the atmosphere - mainly in the upper levels, but we are seeing minor surface-level impacts. This is resulting in reduced air quality in certain parts of the province, although it’s not nearly as bad as it was a few days ago.

SOURCE: AQICN.ORG

Air quality readings are sitting above 100 in parts of Southwestern Ontario, the Golden Horseshoe, and sections of Northern Ontario. That level falls into the “unhealthy for sensitive groups” category, which includes people with asthma, respiratory conditions, young children, and older adults.

If you’re part of a sensitive group, it’s a good idea to limit your time outdoors, keep your windows closed, and consider wearing a well-fitting N95 mask when you have to go outside. These masks can help reduce exposure to the fine particulate matter found in wildfire smoke.

Elsewhere across Southern Ontario, AQI readings are in the 50 to 100 range, which is considered moderate. That’s not a big concern for healthy individuals, but anyone who is sensitive to air pollution may want to avoid heavy outdoor activities like running or biking.

You might also notice a faint smoky smell in the air, but it's not expected to be too strong. Still, it’s a reminder that there’s pollution present, even if the skies don’t look especially hazy.

UPPER LEVEL SMOKE CONCENTRATION - MAP FROM WEATHERBELL

The smoke is expected to stick around overnight and into Monday morning, especially in the lower levels of the atmosphere. By Monday afternoon, we should begin to see some clearing closer to the surface, with air quality likely improving through the day.

Unfortunately, that improvement probably won’t last long. The latest forecast models show another plume of upper-level smoke moving into the region by late Monday. While these models currently suggest limited smoke near the surface, we’ve seen before that they often underestimate how much smoke actually mixes down. So we can’t rule out more air quality issues as the week goes on.

UPPER LEVEL SMOKE CONCENTRATION - MAP FROM WEATHERBELL

Looking ahead, additional wildfire smoke is a strong possibility, especially as fires continue to grow rapidly across Northwestern Ontario. One major concern right now is the fire near Sandy Lake First Nation, which has prompted a full evacuation of the community. That fire is expected to grow further and could become a major source of smoke for Southern Ontario in the days ahead.

Because of its closer proximity compared to fires in Western Canada, smoke from this fire has a better chance of settling closer to the ground by the time it reaches our region. That means more noticeable impacts, even for those outside of sensitive groups.

SOURCE: CWFIS

Some good news: recent rainfall has helped reduce the fire danger in parts of Ontario, Manitoba, and Northern Saskatchewan—regions that have been hit hard by wildfires over the past couple of weeks. This rain may help slow fire growth and support containment efforts, especially in areas where communities are at risk.

However, the same can’t be said for British Columbia, Alberta, and Southern Saskatchewan. These areas are still facing high to extreme fire danger levels, with dry conditions and tough firefighting environments.

Quebec is also showing some concerning signs, with several pockets of high to extreme fire risk. If wildfires do ignite there, it could add yet another smoke source for Southern Ontario in the coming days.

Much Needed Rainfall is Finally on its Way for Most of Saskatchewan This Weekend

Model image showing total rain from friday morning until monday morning, courtesy of weatherbell

Good news Saskatchewan: there's finally rain in the forecast! The bad news is that not everyone will see the rain and strong winds could still be an issue.

To start, we've already seen some scattered showers across Northern Saskatchewan this morning. The rain is expected to continue through the day and into tomorrow, with some pushing into Central Saskatchewan this evening.

This precipitation will be associated with non-severe thunderstorms, like we've seen for most of the week, which could bring strong wind gusts up to 70km/h and possibly small hail. Luckily though, these storms will finally bring a decent amount of precipitation.

Environment Canada forecast for friday afternoon

Early tomorrow morning, light rain will cross through Southern Saskatchewan. Then, in the afternoon, the rain from the north will push southeastward as it wraps around a low pressure system moving south from the Territories.

The rain is expected to fall in in Eastern Saskatchewan through Sunday morning and afternoon, dissipating in the evening and leading to much less rainfall in the Southwest than in the rest of the province. Aside from this region, widespread 10-50mm is expected by the end of Sunday. Luckily, the areas with the worst fires can expect a decent amount of rain this weekend.

Unfortunately, strong wind gusts up to 70km/h are expected to persist through the weekend and this could still pose a challenge for firefighting efforts despite the precipitation and cooler temperatures.

Warm Temperatures Briefly Return With Isolated Severe Thunderstorm Risk for Southern Ontario Wednesday

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While much of late May across Southern Ontario was dominated by unseasonably cool weather, the start of June is shaping up to be a very different story. Over the past few days, temperatures have rebounded to near-seasonal levels across the region, and that’s just a preview of what’s ahead. But enjoy it while you can because a noticeable cool down is expected later this week.

This early June heat has also arrived with a layer of upper-level smoke drifting in from wildfires burning across Western Canada. This smoke has caused a light haze in the sky, giving the air a faint smoky smell, dimming the sun, and slightly suppressing daytime temperatures compared to what we would have seen under clear skies.

The good news is that much of this smoke is expected to clear out across Southern Ontario overnight into early Wednesday morning. While some lingering smoke may remain high up in the atmosphere, it shouldn’t be as thick or widespread as what we’ve seen over the past 36 hours.

With clearer skies, daytime heating will be more effective, giving temperatures a better shot at reaching their full potential. On Wednesday, we’re expecting highs to climb into the upper 20s and possibly even low 30s in some spots.

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A cold front sweeping across the province late Wednesday will bring a shift in the pattern, knocking temperatures back below seasonal for the latter half of the week. This front is also expected to trigger a line of thunderstorms, some of which may be marginally severe.

Primary threats include damaging wind gusts up to 90 km/h, pockets of quarter-sized hail, and localized flooding from slow-moving storms. There is also a very low risk of an isolated tornado, but given the weak storm environment, this threat is quite uncertain and likely limited.

ESTIMATED AIR TEMPERATURE - MAP FROM WEATHERBELL

Much of Wednesday will start off hot and hazy, especially across Southern Ontario. Temperatures will rapidly climb into the upper 20s by early afternoon ahead of the approaching cold front. In some areas, particularly Deep Southwestern Ontario, the Golden Horseshoe, and the Ottawa Valley, temperatures could push into the low 30s.

That said, locations along the immediate shorelines of the Great Lakes will likely remain a few degrees cooler due to the lake breeze. These areas, including communities along Lake Erie, Lake Ontario, Lake Huron, and Georgian Bay, should see highs closer to the low to mid-20s.

As the cold front begins moving in from the northwest, starting around 2 to 4 PM near the Bruce Peninsula and the North Bay and Parry Sound region, we’ll see an almost instant temperature drop. It could fall by as much as 10 to 15 degrees within a couple of hours. The front will then gradually push southeast through the rest of the afternoon and into the early evening hours.

As the temperatures rise, it’s crucial to keep our beloved pets safe and comfortable. Here are some essential tips to ensure your furry friends stay cool this summer:

🚗 Never Leave in Cars: Even with windows cracked, the temperature inside a car can rise dramatically in just a few minutes. On a 24°C day, the temperature inside a parked car can soar to 38°C in just 10 minutes. In 30 minutes, it can reach 49°C! Leaving your pet in a car can be deadly, so never leave them unattended.

If you see a pet left unattended in a car in Ontario:

• Look for the Owner: Note the car's make, model, and license plate number. Go to nearby businesses to see if you can find the owner.

• Call for Help: If you cannot find the owner, call your local animal control or police. You can call the OSPCA at 1-833-9-ANIMAL (264625). If you believe the animal is in immediate distress, call 911 immediately.

• Stay with the Pet: Remain with the pet until help arrives.

🏡 Shade & Shelter: Make sure your pets have access to shaded areas to avoid direct sunlight. A cool, sheltered spot can make a big difference.

💧 Hydration is Key: Always provide fresh water for your pets. Dehydration can set in quickly, so keep their water bowl filled and in a shaded area.

🐕 Limit Exercise: Avoid walking your pets during the hottest parts of the day. Early morning or late evening walks are best to prevent overheating.

🐾 Paw Protection: Hot pavement can burn your pet's paws. Walk them on grass whenever possible, or use protective booties to shield their feet.

⚠️ Watch for Signs of Overheating: Symptoms include excessive panting, drooling, and lethargy. If you notice these signs, move your pet to a cooler area immediately and provide water.

UPPER LEVEL SMOKE CONCENTRATION - MAP FROM WEATHERBELL

Although the smoke won’t be nearly as thick as what we experienced Monday and Tuesday, some light to moderate upper-level smoke may still linger on Wednesday. Forecast models suggest the highest concentrations will likely be around the Golden Horseshoe, including the Greater Toronto Area, Hamilton, and the Niagara region.

There may still be a faint smoky smell in the air at times, but surface-level smoke isn’t expected to be heavy enough to significantly impact air quality. What it could do, however, is hold temperatures back by a couple of degrees in some spots since the sunlight won’t be able to fully break through the smoke layer.

By Thursday, most of this smoke should clear out completely. That said, some models are hinting at another round of wildfire smoke pushing into the region by late this week or into the weekend.

SIMULATED RADAR - MAP FROM WEATHERBELL

Along with cooler temperatures, the advancing cold front will bring the potential for thunderstorms across Southern Ontario. Current data suggests that a line of storms will begin forming early Wednesday afternoon, stretching from North Bay down into parts of Michigan.

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As this front continues to track southeastward, conditions will become more favourable for some of these storms to become locally severe. Isolated threats include damaging winds, large hail, and heavy downpours. The highest risk zone appears to be in a corridor running from Deep Southwestern Ontario through Kitchener and Waterloo, into the Lake Simcoe region, and extending northeast into the Algonquin Park area.

The timing for the strongest activity looks to fall between 3 PM and 6 PM, though it could stretch a bit later, especially in areas near the border. Some model runs even show a rogue thunderstorm crossing into the Windsor or Sarnia area from Michigan during the evening hours.

The overall tornado threat remains low due to the weak storm environment and expected messy storm mode, but it is never zero. Sometimes we do see surprise spin-up tornadoes in Ontario, especially where lake breezes collide and enhance low-level rotation.

After sunset, the severe risk should wind down fairly quickly. However, a few non-severe thunderstorms may continue into the late evening and overnight as the front moves across the Golden Horseshoe and into Eastern Ontario.

Slight Risk for Isolated Severe Thunderstorms on Thursday with 100km/h Wind Gusts, 3cm Hail & Isolated Flooding Possible

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We’re closely monitoring a slight risk for isolated severe thunderstorms this afternoon and evening in parts of central Alberta. Areas such as Edmonton, Edson, Red Deer, Whitecourt, Leduc, Camrose, Rocky Mountain House, Drayton Valley, High Prairie, Slave Lake, Lac la Biche, Westlock, Hinton, Olds and surrounding communities may see these storms. However, as they’ll be isolated, most areas will not receive any precipitation at all.

Damaging wind gusts of 80-100km/h, 3cm hail and isolated flooding up to 50mm are the main risks for these storms. Of course, frequent lightning and torrential rain are also expected for those who are affected by these storms.

The overall tornado risk is low so chances of a spin-up are unlikely. However, we all know that stranger things have happen so definitely make sure to have our free app Instant Weather to get notified of any and all alerts from Environment Canada for your area.

Environment Canada has also issued Severe Thunderstorm Watches for the region, shown below.

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Environment Canada writes:

”Conditions are favourable for the development of severe thunderstorms this afternoon and evening that may be capable of producing strong wind gusts and large hail.

Damage to roofs, fences, branches or soft shelters is possible. When thunder roars, go indoors! Lightning kills and injures canadians every year.

Severe thunderstorm watches are issued when conditions are favourable for the development of thunderstorms capable of producing damaging hail, wind or rain.”

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In addition to the severe thunderstorm risk, the Fire Danger map for Alberta shown below is very concerning as almost all areas of Alberta are under “Extreme” fire danger.

Fire danger map for may 29th produced by the government of Alberta

With the expected lightning, warmer temperatures and drier conditions, it’s very possible we could see new wildfires ignited from these storms today. Please stay safe folks and we’ll post more updates when available.

Slight Risk for Severe Thunderstorms on Monday as a Cold Front Advances Through Alberta

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The past week was fairly quiet, as far as active weather is concerned, with the odd pop-up thunderstorm surpassing the severe threshold and a couple of funnel cloud reports. This week, however, is slated to start off with a bang as a cold front will move into Alberta later this afternoon, stretching the length of the province and triggering the development of thunderstorms over a widespread area.

We’ve already seen some scattered showers across parts of Central and Northern Alberta today, but the severe threat won’t begin until this afternoon, around 2-4pm. These will be fast-moving storms that will quickly develop and organize into a north-south line along the cold front as it crosses the province through the afternoon and evening. Storm activity will rapidly diminish as we get later into the evening, but isolated storms could continue until closer to midnight, if conditions remain favourable.

The greatest thunderstorm risk will stretch from Calgary northward up to Fort McMurray, highlighted in yellow on our map. This large region could see damaging wind gusts of up to 100km/h and large nickel to quarter-sized hail, along with torrential downpours. At this point, the threat of a tornado appears to be unlikely, but it can not be completely ruled out.

Fire danger map for may 26th produced by the government of Alberta

The amount of lightning associated with today’s storms could also be a concern. Warmer temperatures and drier conditions have elevated the wildfire risk over the past week and has led to High to Extreme Wildfire Danger across the entire province. Significant amounts of lightning, despite the presence of precipitation, could easily spark additional fires given these conditions.

Nocturnal Thunderstorm Threat With Damaging Wind Gusts and Isolated Tornado Risk for Southwestern Ontario Tonight

updated map - 10:50 PM (CLICK HERE FOR THE PREVIOUS MAP)

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UPDATE (10:50 PM):

We’ve been closely tracking the line of storms developing across Michigan, and it’s now set to move into Deep Southwestern Ontario over the next few hours.

Based on the latest model data, current environmental conditions, and how well the storm is holding together despite the lack of daylight heating, we believe there’s enough evidence to upgrade parts of Deep Southwestern Ontario to a ‘strong’ (3/5) risk—mainly due to the potential for intense wind gusts.

Large hail up to the size of toonies is also possible, and we can’t completely rule out an isolated tornado.

We’ve also extended the ‘slight’ (2/5) risk further inland to include areas like Goderich and London, as new data suggests the line could stay fairly strong as it tracks deeper into Southwestern Ontario during the pre-dawn hours. Again, damaging wind gusts remain the primary threat.

The line is expected to cross the border just after midnight, with the severe threat gradually tapering off but still continuing until around 3–4 AM.

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ORIGINAL FORECAST

While storm season has had a quiet start in Southern Ontario, things are beginning to ramp up with a late-night storm risk expected between Thursday evening and early Friday morning. A strong line of storms is forecast to form across Michigan late tonight, initially beginning as discrete supercells over parts of Wisconsin and Illinois.

Based on the latest guidance, these storms are expected to organize into a more linear structure as they track eastward, eventually crossing into Southwestern Ontario sometime just after midnight. While they’ll likely lose some of their strength after dark, especially without daytime heating, the atmosphere may still be supportive enough for them to maintain some intensity as they move into our region.

That said, there’s still a fair amount of uncertainty about just how strong this line will be once it crosses the border, and how quickly it might weaken as it tracks northeast through the early morning hours of Friday.

The biggest concern with this system is the potential for damaging wind gusts. This squall line will stretch from the Upper Peninsula of Michigan all the way down through Ohio as it enters Ontario, which could lead to widespread impacts. Areas from the Bruce Peninsula all the way down to Deep Southwestern Ontario are at risk of strong winds embedded within the line.

The highest risk appears to be in Deep Southwestern Ontario, where the line will first cross into Ontario. Regions like Windsor, Leamington, Chatham, and Sarnia are most likely to experience the strongest part of this line. While damaging wind gusts are the main hazard, we also can’t completely rule out the chance for hail and even a brief tornado, especially if the storms arrive a bit earlier than forecast.

Hail up to the size of quarters is possible, and while the tornado risk is considered low overall, it does exist. The biggest concern here is that this is a nocturnal threat. If a tornado were to develop overnight, it would be harder to spot and could be rain-wrapped, making it even more dangerous. That’s why it’s so important to stay alert and have a way to receive warnings while you sleep.

SIMULATED RADAR - MAP FROM WEATHERBELL

Storm development will begin with discrete cells over Wisconsin and Illinois, likely forming into a long line around 8–10 PM near Chicago and across Lake Michigan.

The timing of this formation is crucial. If the line develops sooner and sweeps across Michigan quickly, it could result in a more robust severe risk for Deep Southwestern Ontario, where the environment is more favourable before midnight.

No matter the timing, damaging winds remain the most likely outcome with this type of linear storm setup.

SIMULATED RADAR - MAP FROM WEATHERBELL

As of now, future radar models suggest the storms will cross into Ontario between 1 and 2 AM, hitting areas like Windsor and Sarnia first before stretching further northeast. However, there’s still wiggle room in this timing. It could arrive earlier and stronger, or later and already weakening before reaching our region.

ESTIMATED TORNADO ENVIRONMENT - MAP FROM WEATHERBELL

While widespread wind damage is the primary concern tonight, there is some minor tornado potential—especially in Essex County just after midnight. Again, the odds are low, but not zero.

Because of the overnight timing, it's extra important to have notifications enabled on your phone or weather radio. Make sure you have a way to receive alerts while you're asleep in case a warning is issued. Our free app is a great way to instantly get Environment Canada alerts, along with our custom notifications issued for your exact location.

SIMULATED RADAR - MAP FROM WEATHERBELL

The line of storms is expected to continue northeast through the early morning hours, bringing heavy rain, gusty winds, and frequent lightning to much of Southwestern Ontario and parts of the Greater Toronto Area between 3 and 6 AM.

While the line should gradually weaken during this time, it could still pack a punch in some localized areas. There’s some uncertainty around how long it will be able to hold its strength since the atmospheric environment in Ontario is notably weaker than what the storms had access to in the U.S.

Latest model runs show the system likely fizzles out once it reaches Lake Simcoe, meaning Eastern and Central Ontario probably won’t see much beyond a few scattered morning showers or storms.

Another round of storms is possible Friday afternoon and evening, particularly for Eastern Ontario and parts of Deep Southwestern Ontario. We’ll have more details on that in a separate update.

As it stands, the highest storm risk tonight is in Deep Southwestern Ontario, where we currently have a slight risk (2/5) for severe weather. The main hazard is damaging wind gusts between 12 and 6 AM, though isolated tornadoes and hail up to the size of quarters are also possible.

For the rest of Southwestern Ontario and the Golden Horseshoe, the risk is lower—a marginal (1/5) severe threat—with isolated pockets of wind damage being the most likely outcome. There’s also a very low tornado risk along the Lake Huron shoreline as the line initially pushes into the region. Hail up to the size of nickels could accompany some of these storms.

In addition to the overnight threat, a few isolated pop-up storms are possible during the late afternoon and early evening across parts of Grey-Bruce. While these are not expected to be severe, funnel clouds are possible, including a low-end risk of a landspout tornado. See our custom notification for more on the funnel cloud setup.

Stay weather-aware tonight. Keep your devices charged, notifications turned on, and have a plan in place just in case you need to take shelter quickly. We’ll continue to monitor the latest data and provide updates as the situation evolves, including a possible live stream later tonight.

Up to 75mm of Rain for Parts of Southern Saskatchewan & Manitoba, Along with Worsening Air Quality, Expected to End the Work Week

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It is certainly shaping up to be a roller coaster of a week, weather-wise, across Saskatchewan and Manitoba. The week began with record-breaking heat and relentless winds, which made things feel exceptionally dry and were the catalyst for the spread of multiple wildfires across both provinces. Now, cool Arctic air has flooded south and a low pressure system is pushing its way northward from the Dakotas, which will bring significant rain to parts of Southern Saskatchewan and Manitoba on Thursday and Friday.

Pockets of rain on the leading edge of this system have been pushing northward into Southeast Saskatchewan and Westman already Wednesday evening. This will be followed by a large area of steady, heavier rain moving into this region shortly after midnight and continuing through most of the day Thursday.

The rain will gradually spread further northward Thursday morning and by the afternoon, it should also start to cross the border into the rest of Southern Manitoba. This delay in the start of the precipitation will lead to slightly less rain falling overall, but it’ll be fairly steady for the remainder of the event so a widespread 25-50mm can be expected.

In Southeast Saskatchewan and Westman, the earlier start to the precipitation will lead to this area receiving upwards of 75mm of rain. Considering this region already received a fair bit of rain Wednesday morning, this much additional rainfall could very easily lead to some localized flooding.

The center of this system will stay south of the border and will start making its way eastward early Friday morning. The rain will start to taper off, from west to east, beginning Friday morning, before it completely exits the region Saturday morning.

As far as the wildfire situation is concerned, this rain will definitely help containment and suppression efforts in some areas, but it likely won’t be enough to completely douse the flames. In Southeast Manitoba, where several out-of-control fires are burning as of Wednesday evening, 10-25mm is expected to fall with this system, which will be welcomed support.

In Saskatchewan though, the rain will unfortunately not push deep enough into the province to impact the fires that have been burning near Narrow Hills Provincial Park, to the north of Nipawin, so hopefully the cooler temperatures will be enough to help crews in this area.

The arrival of this low pressure system will also have a negative impact, mostly in Southern Manitoba, but also in Western Saskatchewan. As the low approaches, the wind direction will shift, causing wildfire smoke to start moving westward in Manitoba and southward through Saskatchewan.

But why does this happen? To explain, we need to dig a bit deeper into the science of meteorology.

Modelled low-level Wildfire Smoke Concentration at 12pm CT on Thursday, May 15th. Note: this particular model only extends so far into Canada, but it shows the movement of smoke in both Manitoba and Saskatchewan.

One of the fundamental rules in meteorology is that air will always want to flow from areas of high pressure to areas of low pressure. This is actually the main driver behind wind.

Air doesn’t take a straight path from high pressure to low pressure, though. Thanks to the Coriolis Effect, caused by the spinning of the planet, air travels towards a low pressure center in a more counter-clockwise fashion, as shown below.

diagram showing how air moves around both high pressure and low pressure centers, courtesy of NOAA.

Putting this all together, as the low pressure center gets closer to us, air will naturally travel towards it and this will pull the wildfire smoke along with it. With where the low will be positioned over North Dakota, this means that smoke will travel westward from the fires burning in Southeast Manitoba and Northwestern Ontario and southward from the fires in Northern Saskatchewan.

This is expected to begin early Thursday morning in Manitoba and after sunrise in Saskatchewan, continuing through the day. On Friday morning, as the low pressure center begins its trek eastward, the wind will start to shift direction. This will be much more noticeable in Manitoba, being closer to the low, with the smoke travelling southwestard during Friday morning and then southward by the afternoon.

Given the number of nearby active fires and their sizes, especially the Nopiming Fire, there is already more smoke in the air in Southern Manitoba than in Northern Saskatchewan. This means that greater concentrations of smoke will move into Winnipeg and the Interlake Region on Thursday and it will diffuse along its path southwestward as it curves towards the low. Then, as the winds shift direction, the thickest smoke will still be found closest to the fires and becoming more diffuse the further away.

In Saskatchewan, the smoke from the two fires near Narrow Hills Provincial Park will travel south-southwestward, into Prince Albert and Saskatoon. Given the distance from the low pressure center, the wind shift is expected to be minimal on Friday.

If the wildfire smoke moves into your area, especially at higher concentrations, try to limit your time spent outside, if possible. We certainly hope that with the arrival of the cooler air and the rain in some areas, that firefighter crews will be able to make considerable progress battling these fires and we will soon have some reprieve from the smoke.

Last Day of Heat Wave for Most of Southern Manitoba on Tuesday Ahead of Major Cool Down

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We have one final day of extreme heat ahead for most of us in Southern Manitoba on Tuesday as once again, temperatures are expected to climb as high as 37°C.

There is some relief on the way for the region, though, with cool air expected to start pushing southward Tuesday evening and bringing single digit overnight low temperatures to almost the entire province. This might not be quite enough to cancel the Extreme Heat Warning for all of Southeast Manitoba. This area could still see temperatures in the low 30s on Wednesday, particularly around Steinbach and eastward.

This cool down will bring single digit high temperatures back to much of Southern Manitoba later in the week and overnight Friday, temperatures could even dip below the freezing mark. With a low pressure system developing over the region to end the week, we could even see the return of some mixed precipitation with these subzero temperatures. It will definitely be a case of weather whiplash this week!

Modelled Temperatures (in °C) at 4AM ct on Saturday

First Slight Severe Thunderstorm Risk of the Year for the Prairies Monday Afternoon Through Tuesday Morning

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While we saw some severe storms eventually develop in Southeast Saskatchewan and Southwest Manitoba yesterday, the severe threat for today and into the overnight hours is heightened, resulting in our first Slight Risk of the season.

We’ve already seen heavy rain falling in parts of Central and Southern Alberta today, but thunderstorms have begun to develop and will continue as we progress later through the afternoon and into the evening At this point, it’s possible that these storms may become severe, with the main threat being strong wind gusts and heavy rain. The environment today is also conducive for the development of landspout (non-supercell) tornadoes around Calgary and to the east of the city so we will be watching this situation closely.

It’s further east, in Southern and Central Saskatchewan and Manitoba, that we’re seeing the greatest severe thunderstorm threat. Isolated storms are expected to start developing in the early evening, around 5-6pm and possibly a bit sooner in the afternoon, and models are once again suggesting that the environment could be favourable for the development of supercells.

A bit later in the evening, closer to 7-8pm, we could see some additional storm development in Southwest Saskatchewan as a multicellular line. This complex of storms would travel northeastward across the province and move into Central Manitoba in the early morning hours of Tuesday. It’s during these early morning hours that we could also see more isolated storms develop in Southwest Manitoba.

Large hail, damaging winds, and torrential downpours are all concerns with today’s storms. The possibility of tornadoes is low, but the development of one or two can not be completely ruled out.

Second Day of Temperatures Above 30°C Will Continue to Bake Southern Saskatchewan & Manitoba

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Monday will mark the second day of our heatwave in Southern Saskatchewan and Manitoba. We will once again have a large area expecting temperatures above 30°C, and above 35°C temperatures are possible in a small pocket of Southern Manitoba that includes Winnipeg. Extreme Heat Warnings remain in place from Environment Canada for parts of Southern Manitoba for daytime highs up to the mid 30s and overnight lows only dropping down to the mid teens.

With extreme heat, it’s important to limit strenuous outdoor activities, if possible, or take multiple breaks and drink water often to protect yourself from heat exhaustion and stroke. Early signs of heat exhaustion include: headache, nausea, dizziness, thirst, dark urine and intense fatigue. In the presence of these symptoms, stop all activities and hydrate. Heat stroke, on the other hand, is much more serious. Heat stroke is most identified by confusion and loss of consciousness so make sure to seek immediate medical condition if someone is showing these symptoms.

Marginal Risk for Thunderstorms in Southern Saskatchewan and Manitoba Beginning Sunday Evening

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With the arrival of the first heat wave of the year to Southern Saskatchewan and Manitoba this weekend, we’re also looking at our first real threat of severe thunderstorms for the season.

Isolated storms are expected to develop along the American border in both Saskatchewan and Manitoba this evening, starting around 5-7pm. The storms will travel northeastward into both provinces throughout the evening and into the overnight hours.

Models are suggesting that the environment could be favourable for the development of supercells, but further analysis puts the development of severe storms in question and storms could remain sub-severe. One particular area of interest for possible severe storm development will be in Southeastern Saskatchewan and through the Westman and Interlake Regions.

If severe storms end up developing this evening, the overall threats are expected to be limited. These storms could produce small hail and strong wind gusts, while the possibility of a tornado is unlikely.

First Heat Wave of the Season Will Bring Three Days of Record Breaking Temperatures to Southern Manitoba

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There is a low has that been passing through the Prairies over the past couple of days, which will cross into Manitoba overnight Saturday. It will set up over the region for several days, drawing in hot air from the south. This will lead to an extended period with daytime highs in in the low to mid 30s and overnight lows in the mid teens, triggering Extreme Heat Warnings already being issued by Environment Canada.

With extreme heat, it’s important to limit strenuous outdoor activities, if possible, or take multiple breaks and drink water often to protect yourself from heat exhaustion and stroke. Early signs of heat exhaustion include: headache, nausea, dizziness, thirst, dark urine and intense fatigue. In the presence of these symptoms, stop all activities and hydrate. Heat stroke, on the other hand, is much more serious. Heat stroke is most identified by confusion and loss of consciousness so make sure to seek immediate medical condition if someone is showing these symptoms.

First Strong Severe Thunderstorm Risk of the Season in Southern Ontario on Tuesday With Tornadoes Possible

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After a gruelling winter filled with relentless snow squalls, powerful winter storms, and a major ice storm to top it all off, we are finally shifting gears into more typical spring and summer-like weather across Southern Ontario. But with the warmer air comes the return of severe thunderstorms, something Southwestern Ontario has already gotten a small taste of over the past few weeks.

We have been closely tracking the potential for our first strong severe weather threat of the season on Tuesday. Model guidance has been consistently highlighting the potential for a very active environment, one capable of supporting tornadoes, large hail, and damaging wind gusts. That risk still looks to be on track, although there remains some disagreement between models on exactly where the strongest environment will set up.

At this time, we believe the strongest severe weather risk will focus across parts of Southwestern Ontario, Central Ontario, and into Eastern Ontario. Other areas across Southern Ontario will still carry a marginal to slight risk, meaning a few severe storms could pop up, but the widespread threat will be lower outside the main zone.

Tuesday’s possible storm threats include one or two tornadoes, large hail — potentially up to the size of toonies or even timbits — widespread damaging wind gusts over 90-100 km/h, and heavy rainfall that could cause localized flooding in some spots.

The storm risk will kick off early Tuesday morning as an area of convection moves across the region between 6:00 a.m. and 12:00 p.m. Most of these morning storms should remain non-severe, but we can't rule out a rogue severe cell, especially in setups like this. Where these morning storms track and how quickly they clear out will be important to watch, as leftover clouds or rain could limit how unstable the atmosphere becomes later in the day.

By the early afternoon hours, the environment is expected to rapidly become more favorable for severe weather. Areas along the Lake Huron shoreline will likely be the first to feel the effects, with the risk then spreading into parts of Central Ontario.

Even though we are confident that the setup is capable of producing severe storms, it’s important to stress that storms actually have to form to take advantage of the environment. Not everyone in the higher-risk zone will necessarily see a storm. These will be isolated events, meaning only a small percentage of the region will be directly impacted.

The highest tornado risk will likely occur earlier in the day across Southwestern and Central Ontario, when individual storms (known as discrete supercells) can remain separated and feed off the prime environment around them.

As the afternoon progresses and storms track further eastward, we expect that they will start to merge into more of a line, which would shift the threat more towards damaging winds and heavy rain rather than tornadoes and large hail.

By late afternoon into early evening, the severe weather risk will push eastward into the Golden Horseshoe and Eastern Ontario. The good news is that the risk should wind down quickly after sunset, which occurs around 8:00 p.m.

There could still be some leftover showers or weak storms lingering into the evening, especially across Eastern Ontario, but the threat for damaging weather will rapidly diminish once the sun goes down.

We’ll continue to monitor this setup closely and provide updates as new data becomes available. Stay tuned, and as always, make sure you have a way to receive alerts if storms develop in your area.

Download our free app to instantly get any Environment Canada alerts and our own custom notifications pushed to your phone. We are planning to go live to cover any storms that develop throughout the day on Tuesday. Please subscribe to our YouTube channel here so you can be notified when we go live.

REGIONAL BREAKDOWN

Soggy Last Weekend of April Will Bring Over 50mm of Rain to Parts of the Maritimes

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As we come close to the end of the month, the April Showers will hit in full force this weekend, with at least 20mm of rain expected across the Maritimes by the end of Monday.

Light rain will start to push into New Brunswick from the west in the early morning hours of Saturday, tracking from southwest to northeast. This will be a brief first round of rain that will cross through New Brunswick and into PEI during the morning. In Northern New Brunswick, the cool air could result in some brief light snow falling during the morning, but we’re not expecting much accumulation and it will melt with rain that will follow.

The Annapolis Valley and Cumberland County could see a bit of rain along the southern edge of this initial band as it crosses the region, however, the majority of the rain will come in the following round.

Model Image showing the location and intensity of snow (Blue) and Rain (Green) at 3AM AT Saturday

Not far behind the initial round, the main band of more widespread rain will make its way into the region beginning late Saturday morning. The rain will be very heavy at times as it crosses through the Maritimes for the remainder of the day and into Sunday afternoon.

In New Brunswick, the rain will be heavy during the afternoon and evening before becoming lighter later in the evening and ending overnight. Prince Edward Island can expect the heavier rain to begin in the evening, which will persist into Sunday morning before it tapers off in the early afternoon.

Nova Scotia will see the heaviest rain for an extended period of time with this system. The rain will intensify in Western Nova Scotia starting early Saturday evening and it will spread eastward across the province throughout the evening. It will continue overnight and for most of Sunday morning. It will start to taper off from west to east in the mid-morning, but some areas, particularly along the Atlantic Coast, can expect to see steady rainfall continue into the evening, leading to over 50mm falling.

Model Image showing the location and intensity of snow (Blue), freezing rain (Pink), and Rain (Green) at 12AM aT Sunday

Mid-Sunday morning will see the return of some scattered showers across New Brunswick, which will reach PEI in the late afternoon and continue into early Monday morning. This final lingering band of light rain will push southeastward into Nova Scotia around sunrise Monday and will gradually dissipate in the afternoon and evening.

The entirety of the Maritimes can expect at least 20mm and a widespread 30-50mm is forecast for the region. In Western Nova Scotia, along the Atlantic Coast and into Cape Breton, the heaviest rain is expected, with periods of downpours, which will result in over 50mm of rain and even up to 75mm. If a downpour happens to settle over a particular area for a longer period, closer to 90mm of rainfall is not out of the question.

Strong wind gusts will accompany the rain, reaching up to 60km/h across much of the region Saturday night and Sunday morning. The winds will be stronger in parts of Nova Scotia, especially along the Atlantic Coast and through the Highlands, where gusts could exceed 70km/h, while gusts up to 100km/h are likely in northwestern Cape Breton.

Hopefully with all this rain and some warmer temperatures to end the month, we’ll see plenty of May Flowers!

Post-Easter Storm Could Bring Up to 20cm of Snow to Parts of Saskatchewan and Manitoba

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As we get later into the month of April, there have already been tastes of warm weather across the Prairies, with temperatures climbing into the upper teens and low 20s across parts of all three provinces. Don’t let that fool you because it is still spring in the region and that means the continued possibility of heavy snowfall events. This will be the case beginning Tuesday morning and continuing into Wednesday for parts of Saskatchewan and Manitoba.

Model Image showing the location and intensity of snow (Blue) and Rain (Green) at 5AM cT Tuesday

Steady light snow is expected to continue in West Central Saskatchewan overnight Monday and into Tuesday morning. Early Tuesday morning, a low pressure system will push northward from North Dakota, bringing precipitation to Southeastern Saskatchewan and Southern Manitoba. The two areas of snow will merge before sunrise, creating a wide band of continuous snowfall.

As the morning progresses, the system will stall and the light snow in Western Saskatchewan will taper off. On the other hand, the snowfall will intensify along the Saskatchewan-Manitoba border. Further eastward, into the Central Plains and across to the Ontario border, above-freezing temperatures will result in the precipitation from this system falling as rain.

Model Image showing the location and intensity of snow (Blue) and Rain (Green) at 7pM cT Tuesday

Most of the snow will clear in Saskatchewan through Tuesday afternoon, leaving only the area of heavier snow on both sides of the Manitoba border by the evening. The snowfall will persist over this area overnight and it will gradually dissipate throughout the early morning hours.

In this area of constant snowfall, which includes Melville, Moosomin, and Yorkton in Saskatchewan, as well as Dauphin, Roblin, and Russell in Manitoba, residents can expect up to 20cm of snow accumulation by mid Wednesday morning. Depending on how much intensification we see Tuesday morning, it’s possible that up to 25cm could fall locally.

This much snow over a brief period will definitely make travel tricky throughout the day Tuesday so make sure to take extra caution when out on the roads.

Dangerous Ice Storm Likely This Weekend With Widespread Power Outages Across Parts of Southern Ontario

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Concern is rapidly growing for what is shaping up to be a potentially devastating ice storm this weekend across parts of Central and Eastern Ontario. Prolonged freezing rain, beginning Friday evening, is expected to persist throughout much of the weekend, leading to substantial ice accretion on exposed surfaces.

This storm has the potential to reach ice accumulation levels not seen in years—or even over a decade. With up to 40mm of ice accretion possible, widespread power outages are likely in the hardest-hit regions, including Muskoka, Simcoe County, Kawartha Lakes, Peterborough, and Kingston.

Some of these power outages could last for days or even weeks, especially in more rural areas with dense tree coverage. Trees weighed down by ice are likely to fall, taking power lines with them. Travel conditions will also be significantly impacted, as ice-covered roads become extremely dangerous.

For Northern Ontario, the storm will start as a classic winter system, bringing heavy snowfall to Northeastern Ontario throughout Saturday. A second round of precipitation on Sunday could introduce freezing rain and ice pellets further south, affecting areas like Elliot Lake, Sudbury, and North Bay. Snowfall totals in Northeastern Ontario are expected to range from 20 to 30cm, making travel difficult.

Even the Ottawa Valley will see significant snowfall, with up to 20cm possible, along with a mix of ice pellets. By Sunday, freezing rain could become a concern for the region as temperatures rise and the precipitation type shifts.

PRECIPITATION TYPE - MAP FROM WEATHERBELL

As of Friday afternoon, rain is already moving into Southwestern Ontario. By the evening, precipitation will spread north and east into Central and Eastern Ontario.

Based on the latest data, a band of heavy snow is expected to develop along a corridor stretching from Sudbury through North Bay and into the Ottawa region. To the south, an area of freezing rain will form over the Bruce Peninsula and extend into regions around Lake Simcoe.

ESTIMATED TEMPERATURE - MAP FROM WEATHERBELL

How far south the freezing rain spreads remains uncertain. Model guidance suggests surface temperatures will hover near the freezing mark across Barrie and the Greater Toronto Area (GTA).

Even a fraction of a degree difference could significantly alter how much freezing rain accumulates. If the air remains colder than expected, freezing rain could be more widespread. However, a slightly warmer scenario would push the freezing rain line further north.

Confidence is highest for freezing rain in northern sections of Simcoe County, Kawartha Lakes, and Muskoka. These areas are most likely to remain below freezing for an extended period, allowing heavy ice accretion to build up.

PRECIPITATION TYPE - MAP FROM WEATHERBELL

The most intense icing is expected overnight into early Saturday morning. The worst conditions will stretch from Muskoka through Peterborough and into Kingston.

Once again, temperature will be the deciding factor. Some areas, such as Barrie and Newmarket, sit right on the edge between freezing rain and regular rain. If cold air lingers longer than anticipated, freezing rain could extend as far south as the northern GTA, as well as higher elevations like the Dundalk Highlands.

PRECIPITATION TYPE - MAP FROM WEATHERBELL

Through Saturday morning and afternoon, light to moderate freezing rain or drizzle is expected to persist across portions of Central Ontario, particularly around Lake Simcoe. However, the intensity will decrease compared to the earlier hours.

Further south, rain will continue across Southwestern Ontario and the GTA. This is when we expect the warmest temperatures of the storm. Some areas in Deep Southwestern Ontario, including Windsor, could surge into the 20s, while Central Ontario remains near or below freezing.

PRECIPITATION TYPE - MAP FROM WEATHERBELL

By Saturday evening, another round of heavy precipitation is expected to push into Central Ontario. At the same time, temperatures will steadily drop. Regions that saw rain in the afternoon—including parts of the GTA and Barrie—may transition back to freezing rain.

ESTIMATED TEMPERATURE - MAP FROM WEATHERBELL

Model data suggests that by late Saturday night into Sunday morning, the freezing rain line could shift southwest of the GTA. This could result in several hours of freezing rain across Kitchener, Waterloo, and parts of the Toronto area.

Deep Southwestern Ontario, including Windsor, Sarnia, and London, is expected to remain unaffected, staying well above freezing.

PRECIPITATION TYPE - MAP FROM WEATHERBELL

Sunday morning will bring a gradual transition from freezing rain to regular rain across the GTA as temperatures climb above freezing. However, elevated areas northwest of the city, such as Guelph, Orangeville, and Shelburne, could see freezing rain linger for a few extra hours.

For Central Ontario, the freezing rain will continue into early Sunday afternoon as the main area of precipitation slowly shifts north.

By Sunday afternoon, the Ottawa Valley may begin transitioning from snow to ice pellets and then to freezing rain as temperatures rise.

PRECIPITATION TYPE - MAP FROM WEATHERBELL

Most of Southern Ontario will warm above the freezing mark by late Sunday, finally pushing the freezing rain threat northward.

However, by Sunday night into Monday morning, the risk of freezing rain will shift to Northeastern Ontario, including Sudbury and North Bay.

Meanwhile, heavy snow and ice pellets will impact more northern regions, such as Wawa and Timmins.

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Predicting exact ice accretion remains challenging, as many factors influence how much ice actually builds up. The amount of freezing rain you experience may vary significantly from nearby areas due to microclimate effects, surface conditions, and temperature fluctuations.

Some high-resolution model runs suggest an extreme scenario with localized pockets of over 50mm—possibly even 75mm—of freezing rain. However, because much of this precipitation will fall in a relatively short timeframe, not all of it will necessarily adhere to surfaces.

Given this, we are forecasting general ice accretion between 25 and 40mm in the hardest-hit areas. This includes the northern tip of the Bruce Peninsula, Muskoka, Orillia, Barrie, Orangeville, Collingwood, Lindsay, Peterborough, Belleville, and Kingston.

If temperatures are slightly colder than expected, some locations could exceed 40mm of ice accretion, particularly where conditions allow for more efficient accumulation.

To put this into perspective, we can use the Sperry-Piltz Ice Accumulation Index (SPIA Index). With forecasted ice accumulations of 25-40mm (1-1.4”), this storm falls into a Category 4 ice event—even before factoring in wind.

While we are not expecting extreme winds, gusts of 40-50km/h (25-30 mph) in some areas could push this storm into Category 5 territory. According to the SPIA Index, a Category 5 ice storm results in:

Catastrophic damage to entire exposed utility systems, including both distribution and transmission networks. Outages could last several weeks in some areas. Shelters needed.

For the Greater Toronto Area (GTA), ice accretion amounts will vary significantly. The biggest factor will be how long cold air remains trapped at the surface.

We currently expect between 10-15mm of ice for northern parts of the GTA, including York, Durham, and Peel regions. Kitchener and Waterloo will likely see between 5-10mm.

Closer to the Lake Ontario shoreline—including downtown Toronto—freezing rain amounts should be lower, around 2-5mm. However, if temperatures are colder than expected, ice accretion in the GTA could be higher, so it’s still best to prepare.

To the north, ice accretion amounts will drop off as freezing rain transitions to ice pellets and snow closer to the Ottawa Valley.

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In terms of snowfall, widespread totals between 20-30cm are expected across much of Northeastern Ontario through Monday. This includes Sudbury, North Bay, Chapleau, Timmins, and Kirkland Lake. Even Thunder Bay could see 10-20cm of snow, mainly earlier in the weekend.

Along the Quebec border, snowfall amounts will range from 10-20cm in areas like the Ottawa Valley and Cornwall. Further southwest, freezing rain and ice pellets will be the dominant concern, leading to lower snowfall totals.

This storm remains highly dynamic, with small temperature fluctuations potentially making a massive difference in what type of precipitation falls. We will continue to monitor the latest data and provide updates as the situation evolves. Stay safe and stay prepared.

Potential Major Ice Storm Threat on the Horizon for Southern Ontario This Weekend

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With the end of March approaching and the arrival of April, winter’s grip on Southern Ontario is loosening. However, Old Man Winter isn’t leaving quietly. Instead, the final days of March bring the potential for multiple rounds of heavy freezing rain across parts of the region.

The risk of freezing rain is set to begin late Friday as the first wave of precipitation moves in. This initial bout of freezing rain could be quite heavy at times, particularly across Central and Southern portions of Eastern Ontario. The Greater Toronto Area (GTA) may also see some freezing rain late Friday before transitioning to regular rain as temperatures rise overnight.

A second wave of freezing rain is expected to develop Saturday evening and continue through Sunday. However, this round carries more uncertainty, with forecast models disagreeing on how far north warm air will push at the surface. Some models concentrate the freezing rain in Northeastern Ontario and the Ottawa Valley, while others bring it much farther south, placing the GTA in the bullseye.

While there is still uncertainty regarding the exact track and intensity of the freezing rain, all major weather models agree on the overall setup. Cold air will remain locked in at the surface across parts of Southern Ontario, while a surge of warm air moves in aloft. This combination will create ideal conditions for freezing rain formation.

These conditions are expected to persist throughout much of the weekend, with multiple waves of freezing rain possible. Given the prolonged duration of freezing rain, significant impacts are likely. Thick layers of ice could accumulate on untreated surfaces, including trees and power lines. The weight of this ice may lead to substantial damage to the power grid, with outages that could take days—or even weeks—to repair.

PRECIPITATION TYPE - MAP FROM WEATHERBELL

Focusing on the first round, models are beginning to develop a clearer picture of where freezing rain will be most intense. Initial bands of precipitation should move into Southwestern Ontario by late Friday afternoon or evening.

As this precipitation reaches areas such as Kitchener, Owen Sound, and Barrie, it will encounter stubborn below-freezing temperatures at the surface. This will lead to freezing rain developing across these regions.

Further north, a band of heavy snow is expected to spread across areas near the northern shoreline of Lake Superior, extending into Timmins. In more southern locations, such as Sault Ste. Marie, Sudbury, and North Bay, ice pellets will likely be the dominant form of precipitation.

PRECIPITATION TYPE - MAP FROM WEATHERBELL

Models agree that warm air associated with this system will gradually work its way toward the surface, beginning in the southwest and pushing northeast through the night. As a result, some freezing rain may mix with regular rain, especially southwest of Lake Simcoe and near the Lake Ontario shoreline in the GTA.

The persistence of cold air at the surface remains a major question mark. Some models suggest that cold air will be more stubborn, leading to more sustained freezing rain in the GTA overnight and into Saturday morning.

What is more certain is that a particularly intense band of freezing rain will set up over Central Ontario, including the Bruce Peninsula, Muskoka, Simcoe County, Peterborough, and Kingston. Significant ice accumulation is expected in these areas, with freezing rain continuing into Saturday morning. While freezing rain will persist into the afternoon, it should gradually become more scattered in nature.

In the Ottawa Valley, ice pellets and snow will be the main concern. There remains uncertainty regarding snowfall totals, as accumulation will depend on how much mixing occurs with ice pellets. Estimates currently range from 10 to 20 cm, but if ice pellets dominate, snowfall amounts could be closer to 5 cm.

TEMPERATURE - MAP FROM WEATHERBELL

Looking at the temperature setup for this event, a sharp gradient will be present across Southern Ontario on Saturday morning. This is one of the factors making this forecast so tricky.

Below-freezing temperatures will be well-established over Central and Eastern Ontario, as indicated by areas northeast of the pink line on the map above. Meanwhile, Deep Southwestern Ontario—including Windsor, Sarnia, and London—will experience double-digit temperatures, with no threat of wintry precipitation.

The most uncertain area lies between the orange and pink lines on the map above. This includes much of the GTA and the Grey-Bruce region. Temperatures in these areas will hover near the freezing mark, placing them at the boundary between warm and cold air. If models are off by just a degree or two, it could mean the difference between an ice storm and plain rain.

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This represents our preliminary assessment of the hardest-hit areas from the first round of freezing rain. It’s important to note that this forecast covers conditions through Saturday night, but the threat of freezing rain will persist into Sunday and even Monday. There is less certainty regarding how the second round will play out, so our focus remains on the first round for now.

Confidence is highest for significant ice storm impacts in locations such as Tobermory, Wiarton, Owen Sound, Collingwood, Orangeville, Barrie, Midland, Orillia, Muskoka, Parry Sound, Peterborough, and Kingston. Ice accretion in these areas will likely exceed 10 mm and could even reach 20 to 30 mm in the worst-case scenarios.

As previously discussed, temperatures will play a crucial role in determining the extent of freezing rain along the narrow corridor that includes the GTA and Kitchener. Slightly colder temperatures could mean prolonged freezing rain, while a warmer solution would allow for a quicker transition to rain overnight Friday.

Those in Deep Southwestern Ontario and along the Lake Erie shoreline should see little impact, as temperatures will remain well above freezing, resulting in plain rain rather than freezing precipitation.

For more northern regions along the Quebec border, ice pellets and snow will be the dominant precipitation types. Locations such as North Bay, Pembroke, and Ottawa could see 10+ cm of snow, with a risk of ice pellets and possibly brief periods of freezing rain.

PRECIPITATION TYPE - MAP FROM WEATHERBELL

As the first round of freezing rain winds down across Southern Ontario, lingering pockets of freezing drizzle may persist across Central and Eastern Ontario through Saturday afternoon. In the GTA, temperatures could dip just enough to allow for a transition back to freezing rain later in the day.

The second round of freezing rain is expected to arrive by Saturday evening as energy moves in from the U.S. Midwest.

PRECIPITATION TYPE - MAP FROM WEATHERBELL

Models are in solid agreement that this second wave will set up another band of freezing rain in the same areas hit hardest by the first round, including Central Ontario and portions of the GTA. This freezing rain will persist overnight into Sunday morning. However, by Sunday morning, the models begin to diverge significantly.

A more northern track would see warm air winning out across Southern Ontario, allowing temperatures to rise and leading to a transition to rain near Lake Simcoe. This would push the freezing line northward into Northeastern Ontario and the Ottawa Valley. In this scenario, freezing rain would be confined to areas such as Sudbury and North Bay, while heavy snow would develop from Wawa to Timmins.

Both the Canadian and European models favor this northern solution, which would be the better outcome for Southern Ontario, as it would avoid a second major icing event. However, this would be worse news for Sudbury and North Bay, where a significant ice storm could unfold.

PRECIPITATION TYPE - MAP FROM WEATHERBELL

This more northern track has the warmer air winning out across Southern Ontario during the morning on Sunday. This gradually leads to a switch over to rain near Lake Simcoe as the freezing line puches north into Northeastern Ontario and the Ottawa Valley.

Then freezing rain would be contained to Northeastern Ontario including Sudbury and North Bay. While heavy snow extends from Wawa to Timmins.

Both the Canadian and European models favor this solution. Which would certainly be the better outcome for Southern Ontario as they escape a second icing event. But would be worst news for Sudbury and North Bay which could see an ice storm.

PRECIPITATION TYPE - MAP FROM WEATHERBELL

On the other hand, the American model suggests a much more southerly track, which would place Southwestern Ontario and the Golden Horseshoe directly in the path of heavy icing. This scenario would bring freezing rain through Sunday night into Monday morning, creating hazardous conditions for the Monday morning commute.

If this outcome materializes, widespread school bus cancellations across Southern Ontario would be likely on Monday morning. Meanwhile, areas farther north could see accumulating snow on top of earlier ice buildup.

Unfortunately, a significant cooldown is expected in the wake of this storm. By Monday evening, temperatures will plunge into the negative teens. Any ice that accumulates over the weekend will remain in place for several days, increasing the strain on the power grid as trees continue to fall onto power lines.

Regardless of how this storm unfolds, it is shaping up to be a high-impact winter event with potentially severe consequences in some areas. Prepare for treacherous travel conditions and the possibility of widespread power outages lasting multiple days.

We will provide further updates as the weekend approaches. Stay tuned and stay safe!