No End in Sight for Simcoe County and Grey-Bruce as Endless Snow Squalls Bring the Risk of Over 50cm More Snow on Friday
/Here we go again, say it ain’t snow. It should come as no surprise to residents across the snowbelt east of Lake Huron and southeast of Georgian Bay that more snow is on the way to end the week. After a relentless stretch of lake effect activity, snow squalls are set to ramp back up on Friday as activity currently over Muskoka and the Bruce Peninsula drops southward into Simcoe County and Grey-Bruce.
These areas are no strangers to snow squalls at this point, as they have been dealing with them on and off for much of the past week. Simcoe County did manage to sneak in a brief break on Thursday, but that lull will be short lived. Friday is shaping up to be a sharp reminder of just how powerful these lake effect streamers can be, with snowfall totals quickly piling up once again. By Saturday morning, many communities could be digging out from an additional 25-50cm of snow.
In some localized areas, especially portions of southern Bruce County south of Owen Sound, snowfall totals could push even higher. Some model guidance continues to hint at locally over 50cm where bands become most persistent. On top of that, blowing snow will once again be a major concern. Wind gusts approaching 60 km/h will combine with an already deep snowpack to create widespread drifting. As a result, many local roads and highways are likely to remain closed, and that list could grow through the day Friday as conditions deteriorate.
As snow squalls begin to weaken overnight Friday into early Saturday, the focus will quickly shift to the cold. This setup is expected to deliver what could be the coldest night in years across much of Southern Ontario. Wind chills could plunge into the -40s in some areas, with nearly all of Southern Ontario seeing wind chills in the -30 range by Saturday morning.
PRECIP TYPE - MAP FROM WEATHERBELL
Overnight, snow squall activity currently affecting Parry Sound and Muskoka is expected to migrate southward and settle somewhere between southern Muskoka and northern Parry Sound by mid-morning Friday. This band could become quite persistent as it drifts south, heavily impacting travel corridors.
Highway 400 between MacTier and Barrie and Highway 11 between Bracebridge and Orillia look especially vulnerable. Rapidly accumulating snowfall and poor visibility could lead to partial or full closures along these stretches as conditions worsen throughout the day.
By the afternoon, strong wind gusts in the 60 to 70 km/h range are expected to develop. This will significantly increase the risk of blowing snow and near zero visibility, making travel extremely hazardous even in areas not seeing the heaviest snowfall rates.
Hourly snowfall rates (cm) - MAP FROM WEATHERBELL
Attention will also turn to Lake Huron, where more organized lake effect activity is expected to develop east of the lake Friday afternoon. Current model guidance suggests the most intense and focused band will set up somewhere between Owen Sound and Kincardine, extending inland toward Hanover.
This band has the potential to lock in for an extended period through much of Friday afternoon and evening. Where it becomes stationary, snowfall totals could become extreme. Under the right conditions, some localized spots could see 50cm or more, with an outside chance of totals approaching 75 to 100cm if everything lines up just right. Hourly snowfall rates could approach 10cm at times, with very cold air helping boost snowfall ratios and intensify accumulations.
Additional lake effect activity is also expected to impact Huron and Perth counties, although this snow looks less intense and more spread out. Even so, gusty winds throughout the afternoon will create treacherous travel conditions, especially in open areas that are particularly prone to blowing and drifting snow.
Expect ongoing and possibly expanding highway closures across Grey-Bruce, Huron, and Perth counties throughout the day on Friday as conditions remain dangerous.
Hourly snowfall rates (cm) - MAP FROM WEATHERBELL
As we head into Friday night, the Georgian Bay snow squall affecting Simcoe County should gradually weaken and retreat back toward the shoreline around midnight. Snowfall rates will ease, but blowing snow may remain an issue for a time.
The Lake Huron snow squall impacting Grey-Bruce is expected to linger overnight, though it should slowly weaken heading into Saturday morning. As winds ease and the fetch shortens, bands will gradually retreat closer to the lake.
As always with lake effect snow, totals can vary dramatically over short distances due to the narrow and highly localized nature of these bands. That said, there is fairly strong model agreement that the hardest hit area will fall somewhere around Port Elgin, Chatsworth, and Hanover. An intense and persistent squall in this corridor could lead to over 50cm of snow by Saturday morning.
Communities such as Owen Sound, Flesherton, Mildmay, and Kincardine, along with Midland, Orillia, Wasaga Beach, and Gravenhurst, can expect widespread snowfall totals in the 25-50cm range. There is still some uncertainty with the exact placement of the Georgian Bay squall, with some models keeping it tighter and others spreading it out more. Because of that uncertainty, the zone for 25cm or more stretches from Gravenhurst south toward just north of Barrie, even though the actual hardest hit area will likely be smaller.
The City of Barrie sits right on the southern edge of the main snow squall zone. At this point, it appears Barrie will narrowly miss the worst of the snow, keeping totals closer to 15-25cm, especially toward the south end of the city. That said, there is still a chance the squall dips farther south than expected. One model does bring heavier snow into Barrie, which means locally higher totals closer to 35cm cannot be ruled out.
Elsewhere across Grey-Bruce and into northern sections of Huron, Perth, Wellington, and Dufferin counties, snowfall totals in the 15-25cm range look likely. Some localized areas could still end up closer to 30 or even 35cm, depending on how individual bands evolve.
Lower snowfall amounts are expected across the Greater Toronto Area. However, the Lake Huron squall could brush parts of the western Golden Horseshoe, bringing a quick few centimetres in spots. Farther east, including Durham Region and the Kawartha Lakes, the Georgian Bay squall could deliver around 5-10cm.
Little to no snow is expected across deep southwestern Ontario and far eastern Ontario, which is why those areas are not highlighted on the snowfall map.
While snow squalls begin to wind down overnight Friday, the cold will only continue to intensify. Saturday is shaping up to be potentially the coldest day many areas have experienced in years. Some locations, including Toronto, could be looking at their coldest Saturday morning since 2016.
Temperatures are expected to drop near -30˚C across central and eastern Ontario, with wind chills making it feel between -35˚C and -40˚C. Areas east of Lake Huron and around parts of the Golden Horseshoe may be slightly less cold, but still dangerously so.
Across the western GTA, Hamilton, and Niagara, temperatures should hover in the low -20s, though wind chills will still make it feel close to -30˚C. A similar pattern is expected for parts of Bruce and Huron counties closer to Lake Huron, where slightly milder air off the lake may keep temperatures a few degrees warmer.
WIND CHILL - MAP FROM WEATHERBELL
Northern Ontario will be under the core of this polar air mass, with some of the coldest air on Earth spilling south. Temperatures there could dip near or below -35˚C, with wind chills approaching -45˚C across much of the region. Some model guidance even suggests wind chills near -50, though that remains uncertain.
Once the cold settles in, attention will quickly turn to the next potential system. A high-impact snowstorm is showing signs of developing and could bring significant snowfall across a wide swath of Southern Ontario heading into Monday. Current model trends suggest over 30cm of snow is possible in some areas, including parts of the Greater Toronto Area.
A preliminary forecast for that system will be issued on Friday as we continue to monitor trends and fine-tune the details. Stay tuned.

