Freezing Rain Threat Looms for Southern Ontario on Thursday With a Potential Flash Freeze on Friday

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The rollercoaster of seasons across Southern Ontario continues as we end another week with a potentially messy winter storm. We’ve been treated with fairly mild weather making many think that spring is here - even the rodent weather prognosticator! But we are in Canada after all and winter is far from done with our region.

And that blast of reality is under 24 hours away as we see the risk of prolonged freezing rain across a large swatch of Southern Ontario along with heavy sleet and snow starting Thursday afternoon. It will be followed by a rapid cooldown on Friday morning bringing temperatures well below the freezing mark in time for the weekend. The fact that the extended freezing rain will be followed by a deep freeze is concerning as usually, we see a rise in temperature allowing for any ice to quickly melt. That won’t be the case this time which could lead to longer-lasting impacts including damage from the ice and power outages.

Precipitation will start just after the lunch hour in Deep Southwestern Ontario. For the most part, it looks like freezing rain will be the predominant precipitation type. However, the temperature could be slightly above the freezing mark, especially along the Lake Erie shoreline leading to less freezing rain. May also see some ice pellets further north for regions east of Lake Huron and even some wet snow for the Grey-Bruce region.

The band of freezing rain will continue to expand to the northeast across the Golden Horseshoe by the late afternoon and Southeastern Ontario by the dinner hour. Again, the temperature will be a big factor in determining the overall impact making this forecast a tricky one. Currently, it looks like the cold air will win over with this system allowing for prolonged freezing rain. Although we could see less icing in areas along the shorelines including Hamilton, Toronto and the Niagara region should the temperature stay just above the freezing mark.

Ice accretion in the hardest hit regions could range from 5-10mm by early Friday morning which is when we expect to see the freezing rain come to an end. Less accretion is expected further north and along the shoreline of Lake Ontario and Erie with between 2-6mm of accretion possible.

For Central and Eastern Ontario (including the Ottawa Valley), the story with this storm will be a mix of ice pellets and snow starting Thursday evening and continuing into Friday morning. Overall accumulation here will range from 8 to 16cm of snow along with up to 2-6cm of ice pellets. Snow will come to an end by late Friday morning so expect some impact on the morning commute including possible school bus cancellations. We will have more information on that in our daily ‘snow day’ forecast here.


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