Winter Storm to Impact Southern Ontario This Weekend; 20+cm of Snow and Prolonged Freezing Rain Risk Possible in Some Areas

It’s hard to believe that we’re almost into the middle of December and have really only had a few big winter storms this season. The month started with a bang as some areas south of Georgian Bay received a dumping of snow. Otherwise, the month has been fairly quiet but that will change as we head into this weekend as an approaching system is set to deliver a wintery blast to Southern Ontario. Unlike the storm we saw at the beginning of the month, this one will be a classic winter storm lasting for about a day with heavy snow to the north, freezing rain risk in the middle and heavy rain to the south.

A few days ago there was some uncertainty in the track of the system which would determine who sees what when it comes to precipitation type. We’re starting to get a better idea and it looks like the heaviest snow will be located through northern parts of Central Ontario and into Northeastern Ontario. For the rest of Central Ontario and into the Ottawa Valley, there is the threat of several hours of freezing rain before slowly transitioning over to rain. And then for those south of Lake Simcoe through Southwestern Ontario and along the Lake Ontario shoreline this will be mainly a rainfall event. Keep in mind this track may change and would shift the forecast either to the north or south.

Precipitation will start creeping into the province early Saturday morning starting with the regions further to the west around Lake Huron and Georgian Bay. Aside from the higher elevations of the Dundalk Highlands, it will come down as rain for areas south of a line from Owen Sound to Barrie and through Peterborough. Light to moderate snowfall will start spreading across Central Ontario and into Eastern Ontario around the noon hour.

An area of freezing rain will start affecting areas further south like the Dundalk Highlands, Orillia/Bracebridge, Bancroft and Ottawa. This could linger into the evening and maybe overnight in some areas with persistent moderate to heavy icing during this time. Untreated surfaces like sidewalks and rural roads will certainly become quite icy in the affected regions so travel with care. Power outages are also possible so be prepared for that.

We’ll continue to see the storm’s impact continue into Sunday with heavy snow through northern parts of the region and freezing rain from Georgian Bay through the Ottawa Valley occurring into Sunday morning. Rainfall will start to mix in for Simcoe County and maybe as far north as Southern Muskoka and the Ottawa Valley early Sunday. For those who are seeing the heavy snow, some freezing rain may mix in as the mixing line moves to the north. The precipitation will start to taper off during the afternoon on Sunday with temperatures dropping to below the freezing mark as the system moves out. This could cause some icy conditions in areas that saw the rainfall earlier in the day although looks like it’ll be gradual so a flash freeze isn’t likely.

As far as accumulation, we’re looking at around 15-30cm of snow through Sudbury, North Bay and Algonquin Park. Snow totals will drop off to the south as more freezing rain mixing in with Huntsville and Parry Sound seeing around 10-20cm of snow and a few hours of freezing rain towards the end. Southern Muskoka through Bancroft and into the Ottawa Valley will see mainly freezing rain with significant ice accretion between 6-12mm and as much as 5cm of snowfall accumulation. The rest of Southern Ontario will either see a few hours of freezing rain or just all rain with rainfall totals between 10-25mm by the end of the event. Again, a shift in the track could change who sees what so stay tuned for our final detailed forecast to be released Friday evening.