Temporary Return to Winter As Snow Squalls Could Dump Up to 30cm of Snow Through Parts of Southern Ontario’s Snowbelt by Monday

We might have been treated to quite a mild start to spring across Southern Ontario so far, but that is about to change over the next few days. Cold arctic air will flood into the region late Saturday night into Sunday morning bringing temperatures that feel more like early December than the beginning of spring. It will only get colder as we head into Monday with wind chills approaching the -20s in some parts of Southern Ontario as you start the day on Monday!

This colder area will also help turn back on the lake effect snow machine over the next few days with snow squalls potentially bringing significant snowfall accumulation to parts of the Snowbelt. Poor driving conditions with blowing snow and rapid snowfall accumulation will be a common occurrence starting early Sunday morning lasting throughout the day and into early Monday. Localized road and highway closures are likely in the affected region, so it’s a good idea to avoid travelling east of Lake Huron and south of Georgian Bay until later on Monday.

Light scattered flurries are currently ongoing in parts of Southwestern and Central Ontario as of Saturday afternoon as temperatures slowly make their way below the freezing mark. By midnight, we should see some more persistent and heavy bands of snow develop around the eastern Lake Huron shoreline and south of Georgian Bay. It doesn’t appear that this area of lake effect snow will be particularly organized until we get into mid to late morning on Sunday as a more intense squall will set up. The main squall will be located off Lake Huron somewhere between Kincardine and Goderich along with a secondary squall off Georgian Bay coming inland over Meaford and extending into the Collingwood/Wasaga Beach area.

There is some disagreement among the models on the exact wind direction which makes it difficult to narrow down the placement of the squalls. However, it does appear that the squall off Lake Huron will meander around a bit throughout the day on Sunday which should help limit the overall accumulation for each location. It looks like it will start out near Goderich, Grand Bend and Exeter early Sunday morning before shifting northward towards Kincardine and Hanover by the afternoon. It should slowly make its way back to the south and could lock in for a few hours around Exeter and Stratford into early Monday morning.

For Georgian Bay, current indications suggest that the lake effect snow will be mostly contained to the shoreline with a focus on the Collingwood, Meaford and Wasaga Beach region. By Sunday evening, the snow squall may strengthen to an extent and reach further inland towards Barrie, Innisfil and across Hwy 400 into York Region. This will bring the chance for a quick 5-10cm of snow in this area with locally even higher amounts if it locks in for several hours. Parts of the GTA and the City of Toronto may even see some heavier snow around midnight as the edge of the squall shifts into the city, but accumulation isn’t expected to be significant.

The snow squall activity will taper off by late Monday morning or early afternoon. Depending on the strength of the squalls in the morning, it could prompt some school bus cancellations around Lake Huron and Georgian Bay on Monday. In terms of overall snowfall accumulation including tonight, Sunday and early Monday, we expect that some areas east of Lake Huron could pick up to 30cm of snow. This includes Goderich, Kincardine, Wingham, Listowel and Hanover. However, not everyone will see anywhere near 30cm as snow squalls are very localized and the exact totals for each location will vary significantly from a few centimetres to near 30cm. It all depends on the wind direction and intensity of the squall, but the potential is there.

Surrounding regions including Grand Bend and Stratford along with the Southern Georgian Bay shoreline can expect up to 20cm by Monday from the snow squall activity. Those in London, K/W, Owen Sound and Barrie could see the occasional brief snow squall move through the area leading to accumulation up to 10cm. Do note that there is some higher uncertainty around the Barrie area and southward along Hwy 400 where one model does show that the squall could become quite intense overnight Sunday. It’s not out of the question that localized accumulation here approaches 15-20cm, but there isn’t enough confidence to include it on the map. In addition to this, the Niagara region mainly through Fort Erie could see a brief squall early Sunday morning off Lake Erie before it moves stateside leading to up to 10cm of snow.