Messy Winter Storm to Bring Potentially Significant Snowfall and Freezing Rain to Central and Eastern Ontario Between Saturday and Sunday

For most of Southern Ontario, the upcoming ‘winter’ storm will feel more like a fall storm with above freezing temperatures and rain starting Saturday morning. The same can’t be said for areas throughout Central and Eastern Ontario where the clash of colder air and this system will create quite the messy mess with significant snowfall through more northern parts of the region and prolonged freezing rain to the south. By Sunday, locations like North Bay and Algonquin Park could see as much as 30cm of fresh snowfall accumulation. A freezing rain threat will exist through the higher elevations northwest of the GTA, east of Georgian Bay and into the Ottawa Valley. For some areas, it could lead to a significant icing with 4-8 hours of persistent heavy freezing rain. On the warm side of the system, we’ll see general rainfall amounts between 10-20mm through Southwestern Ontario and the GTA with locally over 20mm east of Lake Huron.

Timing

TIP: You can click on the image to open it in a new tab and be able to zoom into the graphic.

TIP: You can click on the image to open it in a new tab and be able to zoom into the graphic.

The storm will begin to affect Southern Ontario early Saturday morning with rainfall south of Lake Simcoe (freezing rain in the higher elevations near Orangeville) and heavy snow through Central and Eastern Ontario. We haven’t put together a timeline graphic for the GTA and Southwestern Ontario as it would be redundant with the only precipitation type being rain for this event. Rainfall will be ongoing from the early morning and throughout Sunday in this area.

As we head into the afternoon, we’ll start to see a zone of freezing rain develop from around Bracebridge through Bancroft and into the Ottawa Valley. Freezing rain will continue for some areas for several hours before slowly transitioning over to rain. The Dundalk Highlands including Orangeville could see over 12 hours of freezing rain which would result in significant icing. Heavy snow will continue to pile up further north through the Parry Sound and North Bay corridor. By the evening most areas will likely have switched over to some rain except to the north. Colder air will flow in behind the system causing locations like Huntsville and Parry Sound to switch back over to heavy snow overnight.

Precipitation will start to taper off Sunday morning or early in the afternoon.

This storm will be giving us a sampling of almost all the different precipitation types across Southern Ontario so we have 3 different accumulation maps for snowfall, freezing rain and rainfall.

As we’ve mentioned, the heavy snow will be contained to the more northern regions of Southern Ontario including the northern tip of the Bruce Peninsula. Locations like Tobermory, Britt, Sundridge, North Bay and Algonquin Park can expect between 20-30cm of snowfall accumulation. The totals will drop as the further south you go as more freezing rain and regular rain mixes in. Between 10-20cm is possible through Northern Muskoka and into the Barry’s Bay and Pembroke. After this, the snowfall gradient will get quite tight with Bracebridge, Haliburton and Bancroft right on the line of heavy snow and will likely end up around 4-8cm of accumulation. The rest of Southern Ontario will see less than 2cm of accumulation.

With the freezing rain, there are two areas of concern with one being through Central Ontario and another encompassing the higher elevations southwest of Collingwood. This small zone that includes Shelburne in the bullseye could see extremely localized ice storm conditions with upwards of 10mm of ice accretion. Orangeville and Flesherton have the potential to see between 6-12mm of ice accretion. Please note that this is an extremely localized event dependent on elevation so a location like Shelburne could be hit hard while Angus sees very little freezing rain.

Further north into Central Ontario and Central Ontario, several hours of freezing rain is also possible in locations like Huntsville, Haliburton, Bancroft and Renfrew which may pick up between 6-12mm of ice accretion. Power outages and significant impact to travel is expected in this area throughout Saturday.

A zone extending from the eastern Georgian Bay shoreline (Parry Sound, Bracebridge) and east into the Ottawa Valley will see a few hours of freezing rain with around 2-6mm of ice accretion. Other areas through Central and Eastern Ontario like Orillia, Peterborough and Bancroft may see one or two hours of freezing rain but accretion will be limited.

Those that don’t see the wintery precipitation which includes much of Southwestern Ontario into the GTA will see instead get heavy rainfall. In most areas, this rainfall totals will range from 10-20mm although some regions east of Lake Huron including Goderich, Kincardine and Owen Sound could exceed 20mm. The rainfall totals will be lower further north as more freezing rain and snow mixes in through Central and Eastern Ontario.