Southern Ontario: Winter Storm Outlook for Tuesday, February 22, 2022

Forecast Discussion

A system is expected to move into Southern Ontario early Tuesday morning bringing a messy mix of precipitation just in time for the Tuesday morning commute. For Southwestern Ontario through the GTA along the Lake Ontario shoreline, it will come down as mostly rain with a slight risk of some freezing drizzle. There could still be some flooding here as we’re expecting 10-20mm of rain throughout the day on Tuesday.

Further to the north and west, there will be some more persistent cold air over K/W, Orangeville, Barrie and Peterborough allowing for more sustained freezing rain. A few hours of freezing rain is possible before switching over to regular rain later in the morning as temperatures climb above the freezing mark.

There is some uncertainty regarding the exact speed of the warm-up through Central and Eastern Ontario. Some models show the below-freezing temperatures holding on for hours through the afternoon and early evening. This would allow for a very sustained period of freezing rain through Muskoka, Bancroft, Algonquin Park and the Ottawa Valley from Tuesday morning lasting throughout the day. The transition would only start to happen around the dinner hour and could last even longer for the Ottawa Valley.

However, other models show a faster switchover and only show significant ice over Algonquin Park and the Ottawa Valley. Those further south would see the switchover during the afternoon, but still, 2-6mm of ice accretion is possible from the freezing rain in the morning. The Ottawa Valley could experience quite the freezing rain event with up to 12mm of ice accretion. This would cause quite an impact on the region, especially with it lasting for 6-12 hours. Be prepared for some power outages and icy road conditions through the affected regions

Most of Southern Ontario should have switched over to rain by late Tuesday morning allowing for some melting. But there is the potential for a flash-freezing Wednesday morning as temperatures plunge below the freezing mark. For Northeastern Ontario, it will come down as sleet with some snow as well as accumulating snow north of Sudbury.

A snowfall accumulation forecast for Northern Ontario will be issued on Monday once we get a better idea of the sleet and snow dividing line. We will also have a more detailed freezing rain risk map after we figure out the speed of the switchover through Central Ontario.