We knew southern Ontario was overdue for lake-effect snowfall, or just snow in general, but no one could have seen a 50-centimetre threat coming for the first round of it this year.
After one of the warmest fall seasons on record across Canada, a major pattern reversal is underway across the country. The Prairies, after just experiencing a major snowstorm on the weekend, are about to see bitterly cold temperatures that will drop into the -20s, or -30s for some.
SEE ALSO: Coldest air of the season to push into Canada to start December
And now it’s Ontario’s turn for the cold and snow. We could see some significant snowfall accumulations for many areas in the traditional snowbelt regions near Lake Huron and Georgian Bay.
In fact, could we see 50 cm of snowfall by the end of the weekend? Let’s break down the possibility.
An Arctic air outbreak is expected on the Prairies this week as a Siberian air mass crossed the North Pole this past weekend. It will track through the Prairies and eventually make its way into Ontario, but it will be modified (warmed up) by the time it reaches the Great Lakes. That has been one of the missing ingredients for snowfall this season.
Temperatures are expected to slowly drop through the week as colder air continues to get ushered in with northwesterly winds, with below-normal temperatures expected by late week and lasting through weekend––the first time in a couple of months. As temperatures drop, it will allow snow to fall versus rain in most areas, but the question is how much is expected by the weekend?
There are a couple of different opportunities to accumulate snow this week, so it can slowly build up by the end of the week, but come the weekend, it will start to pile up quickly. We’re expecting a multi-day, lake-effect snowfall event.
So, the short answer is yes, 50 cm of snowfall is possible. The caveat to the answer is it will only impact a small amount of Ontarians.
Lake-effect snow squalls are thin bands of snow that set up off the lake and are quite heavy in the most intense bands, which can span only a few kilometres or can be more than 10 kilometres wide. It can heavily impact one city or town, and the locales on either side might only see a little bit of snow.
So, 50 cm of snow is expected in the heaviest snow bands this week.
The greatest chance of it occurring will be somewhere on the southeast shores of Georgian Bay. So, get those snowblowers ready as it could be your community that gets 50 cm by the time Dec. 1 gets here.