We are currently tracking a large system as it crosses Ontario and moves into Quebec and Atlantic Canada over the coming days. This system will bring heavy rain, heavy snow and some light freezing rain to portions of Southwestern, Central, and Eastern Ontario.
Snowfall:
Notice: Due to a quicker changeover from rain to snow across Southwestern Ontario, we have updated our forecast to better align with the current situation for accuracy. This includes increasing snowfall totals across Southwestern Ontario. Also with this change comes better confidence across Eastern Ontario of 15-20cm in the orange (4) region.
Areas in the orange and marked with a '4' can expect snowfall totals between 10 and 15cm with local amounts as high as 20cm. This includes much of Eastern Algonquin Park extending across most of Renfrew County including Barry's Bay. This area also extends just north of Bancroft. Strong wind gusts between 45 and 65km/h across the region in the late afternoon and evening will cause some hazardous driving due to the moderate to heavy snow falling alongside blowing snow. Must of the region should see totals near 15cm. Some weather models do expand localized amounts as high as 25cm although this seems unlikely and therefore, was left out of our forecast.
Areas in the yellow and marked with a '3' can expect snowfall totals between 10 and 15cm. This includes portions of Central Algonquin Park including Brent as well as Haliburton, Bancroft, and Renfrew. This also includes Kaladar and areas just north and west of Sharbot Lake. Snowfall amounts generally near 10cm are likely with some areas slightly below and some areas slight higher in a range of 7-13cm. Local amounts may reach as high as 15cm. This is most likely towards the orange region near Bancroft. Blowing snow will be a concern into the evening as the winds begin to pick.
Areas in the green and marked with a '2' can expect snowfall totals between 5 and 10cm. This includes much of Eastern Ontario including Huntsville, Ottawa, Smiths Falls, Brockville, Kingston, Sharbot Lake, Belleville, Peterbourough. A majority of these areas such as Brockville, Huntsville, and Ottawa will only see near 5cm with amounts slowly increasing further inland. Areas between Peterborough and Sharbot Lake have the best chance at seeing totals reach up to 10cm. Snowfall totals over Prince Edward County towards Belleville and Kingston will likely see amounts between 4 and 7cm. In Southwestern Ontario, areas from Orillia and Barrie through to Newmarket, Shelburne, Orangeville, Kitchener, Cambridge, Brampton, and Guelph can expect in the 4-8cm range.
Areas in the blue and marked with a '1' can expect snowfall totals under 5cm. Some areas could see no snow at all, especially for areas between North Bay and Parry Sound, as well as Grend Bend along the shores of Lake Huron towards Kincardine and Goderich.
There is some uncertainty as to how far south the snowline will push into the GTA towards Lake Ontario. Because of this, we have highlighted portions of York, Etobicoke, Mississauga, Milton, Kilbridge, Copetown, Ancaster, Hamilton, and the Niagara region in the area of interest. In the area of interest, snowfall amounts between 2-4cm are expected although pockets of 4-8cm are possible if the snowline can push far enough south to impact these areas for an extended period of time.
Freezing Rain Forecast:
Areas in the green and marked with a '2' can expect ice accretion totals between 2 and 5mm. This covers portions of Algonquin Park extending into Renfrew County near Barry's Bay, Renfrew, and Bancroft. Amounts in the range of 2-4mm are most likely with pockets of 4-7mm, mainly towards Renfrew.
Areas in the blue and marked with a '1' can expect ice accretion totals in the range from a trace to 2mm. This includes portions of Eastern Ontario including Prescott and Russell and Ottawa where a trace to 1mm is likely. Areas further east towards Sharbot Lake, Pembroke, Deep River, and Haliburton, freezing rain totals near a trace are likely. From Haliburton and Muskoka southwest towards Orillia, Barry, Newmarket, Shelburne, Guelph, Kitchener through to Woodstock, London, Chatham and Windsor, a trace is possible. A majority of this region will not see any freezing drizzle or freezing rain although it is possible. It is most likely from Barrie south towards Newmarket, Guelph, Shelburne, Kitchener and Stratford where a trace is most likely. Between Woodstock and London, one or two patches of a trace are possible. Finally, much of Essex County and Chatham could pass with a trace or nothing at all. Travel impacts will be light in areas which receive little to no freezing rain and primary see a trace of snow with some light rain.
Rainfall (No Map):
Across Eastern Ontario from Prince Edward east towards Kingston and Brockville, rainfall totals between 20 and 30mm are likely. From Sharbot Lake through to Ottawa, Smiths Falls, and Cornwall, rainfall totals between 25 and 35mm are likely with pockets towards 40mm. Elsewhere, a general 5-10mm is likely from Guelph and Woodstock east into the GTA with a trace to 5mm likely for areas near Windsor, Chatham and London. Locally up to 20mm is possible for portions of Niagara if warmer air dominates.