Toronto – A strong snowstorm appears increasingly likely to bring significant snowfall accumulation to all parts of Southern Ontario this weekend starting Saturday morning and lasting into Sunday. Widespread accumulation between 15-30cm is expected with slightly less around the Lake Ontario and Erie shoreline due to the snow being wetter causing reduced accumulation. Strong wind gusts reaching 50-70km/h during the afternoon and evening on Saturday will likely cause blowing snow with reduced visibility. Overall this system is shaping up to be easily the biggest snowfall many areas have seen this season so be prepared for travel delays across the region and if possible consider just staying home.
Since our last update, we’re continuing to see very good agreement among the models and even some growing confidence in many areas exceeding 20cm and maybe even 25cm of accumulation over this weekend. With this, we’ve decided to introduce a new 20-30cm zone on our map that encompasses much of Central and Eastern Ontario along with regions east of Lake Huron. Other areas generally remain the same except for Extreme Southwestern Ontario where it appears accumulation will exceed 10cm after all as the latest data shows very heavy snow early Saturday morning before the switch over to rain occurs around noon. Although it should be mentioned that the rain could melt some of the snow in the Windsor area so you might have more than 10cm if you measure it late Saturday morning, but less than 10cm when you go out later in the day.
Some of the more high-resolution models are starting to suggest a ‘dry slot’ just south of Lake Simcoe which could result in lower snow totals through York Region and potentially into the Barrie area – we’ve outlined this in our map above by moving that area into our 10-15cm forecast range. The first flakes will begin to fly around 1-4 am starting with Extreme Southwestern Ontario such as Windsor and Sarnia where the snowfall will be quite heavy at times through the morning hours. By late morning, the bands of heavy snow will move into the rest of Southwestern Ontario and the GTA/Niagara region. For Extreme Southwestern Ontario and regions around Lake Erie, we expect some mixing with freezing rain, ice pellets or rain to occur as temperatures climb to near the freezing mark near noon.
By the afternoon, the storm will be underway across all of Southern Ontario with heavy snow encompassing the entire area although the snow will become less intense towards the southwest as the bulk of the moisture moves to the northeast. The latest data indicates that any mixing will be limited to the Lake Erie shoreline although we still expect lower totals through the GTA since temperatures will be above the freezing mark and the snow will be quite wet so a lot of it will melt on contact. Moderate to heavy snow will continue through Central and Eastern Ontario into the evening and past midnight before clearly overnight and early Sunday morning. Continuing to see the potential for snow squalls to develop east of Lake Huron during the day on Sunday hence why we’ve upped the expected snow totals to 20-30cm for that area.
We’ll continue to monitor this and provide any updates in real-time if there are any significant changes to the outcome. Stay with us for the very latest details!