Southern Ontario: Snow Squall Outlook for Saturday, December 4, 2021

Forecast Discussion

Disorganized lake effect snow is expected to develop off Georgian Bay starting Saturday morning and will further organize into stronger snow squalls later in the day. The bands will initially favour a southwesterly flow which would put the Parry Sound, Britt and Huntsville area in the heaviest snowfall rates during the early part of Saturday. However, this lake effect snow will quickly sink southward towards the Midland, Bracebridge and Orillia area by the afternoon with more organized squall activity developing. This will allow for some rapid snowfall accumulation with the worst conditions expected late afternoon and into the evening hours.

There is still some uncertainty in regards to the placement of the squall where it could end up stalling as far north as Bracebridge and as far south as Orillia. Somewhere in this corridor, we expect to see the potential for up to 25cm of accumulation by the end of Saturday. The Bruce Peninsula will also be affected by these squalls with the highest totals found around the Tobermory area. As is typical with these events, it’s important to emphasize that just because we’re saying that certain regions could see up to 25cm doesn’t guarantee they’ll see significant snowfall accumulation. It just depends on where the squall sets up and the intensity which can be quite hard to predict.

The squall could stretch quite far inland at times and may affect the Northern Kawartha Lakes region and even northern parts of Peterborough county. Accumulation here has the potential to reach up to 5-15cm. Southern parts of Simcoe County such as Collingwood and Barrie should escape the worse. Although it’s possible they see some brief snow squall activity with up to 5-15cm of snow possible. Surrounding regions will see up to 5cm with scattered lake effect flurries, but not much impact is expected. The snow squall activity should come to an end just after midnight and early Sunday morning as an approaching winter storm shuts off the lake effect snow machine. More details on that winter storm that will affect parts of Southern and Northeastern Ontario starting Sunday afternoon are coming soon.