Arctic Air Returns to Southern Ontario as a Potential Snow Squall Outbreak Looms for Parts of the Snowbelts; Up to 100cm Possible in Some Areas Starting Saturday Through Next Week

Disclaimer: This is a very preliminary forecast and should only serve as a rough idea of the potential impacts. The exact accumulation will depend on wind direction and the strength of the snow squalls. Check back for more detailed and precise forecasts in the coming days.

A significant cool down is on the way for much of Central and Eastern Canada over the next week and Southern Ontario will definitely not be spared from the colder temperatures. For our friends out in the Prairies, this cold spell could bring potentially near record-breaking temperatures with the air temperature near -40°C and wind chills making it feel like -50°C! While we won’t come anywhere near those temperatures, it will still be quite cold compared to what we’ve become accustomed to this winter - overnight lows will be regularly around -10°C to -20°C perhaps as low as -25°C in some of the more northern regions.

Unlike those out in the west, we also have to deal with the Great Lakes which are still mostly wide-open and prime for lake effect snow activity with the right ingredients. Those ingredients are expected to come together beginning Friday evening with temperatures plummeting to well below the freezing mark combined with strong southwesterly to westerly winds. Intense snow squalls should develop late Friday evening off Georgian Bay and Lake Huron curing across the Bruce Peninsula and over Georgian Bay before coming back inland east of Georgian Bay. The hardest-hit locations will include Tobermory, Wiarton, Owen Sound, Parry Sound and northern parts of Muskoka. Combined with the system on Friday, accumulation over the next 3 days could approach 50cm particularly around the Parry Sound area and the Bruce Peninsula.

The squalls will be quite strong at times especially during the day on Sunday bringing near-zero visibility and rapid snowfall accumulation with hourly snow rates reaching 5-10cm in the strongest part of the bands. We may also see some squalls off Lake Ontario and Erie drift far enough northward to affect locations like Port Colborne, Fort Erie, Prince Edward County and Kingston during the evening on Friday. The Lake Ontario and Erie squalls will shift back south of the border overnight into Saturday morning. Total accumulation in this area will range from 10-20cm with locally higher amounts depending on how quickly the squalls move back stateside. It appears that all of the squalls will weaken somewhat later Saturday into Sunday as a weak system approaches from the west. This system won’t bring much in terms of snowfall but will temporarily shut off the lake effect snow until Sunday evening.

Several more rounds of squalls are expected from Sunday evening through Monday evening and then again during the middle of next week continuing until next weekend. Current data suggests it will be a predominately westerly to southwesterly flow so regions east of Georgian Bay along with the Grey-Bruce region will continue to pile on at least 15-30cm of snow with each round and perhaps more in localized spots. With 3-4 rounds of squalls expected over the next week, some areas could easily come close or even exceed 100cm (or a meter) of snow by the end of the week.

As we’ve said, this won’t come all on one day and is spread over 7 days so impacts won’t be as significant compared to a shorter timeframe. Regardless, travel will be likely near impossible through the affected regions within the snowbelts at times over the next week so consider avoiding any travel if possible. Be prepared for sudden whiteouts and snow-covered roads with the intense snow rates that can be found in some of these squalls. Keep in mind this is still several days away and should the wind direction change then it will shift the heaviest snowfall accumulation into other areas. We’ll have more details as we get closer and issue a forecast for each lake effect event separately. This forecast is just a ‘preview’ of what could be coming over the next week.

Stay tuned for our detailed forecast on the first round of snow squalls beginning Friday evening and continuing through the weekend. It should be posted by Friday afternoon.