We are closely watching a weak system expected to slide through Southern Ontario. Rain can be expected for much of the Extreme South with snow in Northeastern and Eastern Ontario, freezing rain between these regions.
Blue or '1':
Areas in the blue or marked with a '1' can less than 2mm of ice accretion. This includes the lakeshores of Huron, Erie (excluding Essex County) and Ontario. This risk extends further inland to include all of Lambton County, the remaining portion of Middlesex County, the region of Niagara, the Bruce Peninsula as well as everything between Parry Sound, Huntsville, Bancroft, Macdoc, Tamworth, and Kingston westward. Local totals may reach towards 2 to 4mm although this is unlikely.
Green or '2':
Areas in the green or marked with a '2' can expect between 2 and 5mm of ice accretion. This includes a large portion of Southwestern Ontario extending into the GTA and Extreme South as well as portions of Central Ontario. This includes an area between Owen Sound, Wingham, Lucan, London, Delhi, Hamilton, Brampton, Vaughan, Peterborough, Orillia, Midland, and everything in between. Most areas should see near 2mm, although amounts towards 4 and 5mm are possible. In the 'Area of Interest' which extends from the Dundalk Highlands south into Wellington, Perth and Oxford Counties as well as the Region of Waterloo, there is the risk most places reaching between 3 and 6 with amounts as high as 4 to 8mm of ice accretion. There isn't enough confidence to upgrade to the level 3 legend risk although the chance is not-zero for this to occur.
Beginning between 6 and 8am, scattered rain will move along the shores of Lake Erie and over Essex County/Chatham Region. Scattered freezing drizzle will be possible over Lambton County through to Niagara for 2-4 hours before fully changing over to rain. The freezing rain will move north into Huron, Perth, Grey, Bruce, Wellington, Dufferin Counties including Halton, Peel, and Waterloo regions. The freezing rain will affect this region between 8am and 12pm for most places with lingering freezing precipitation over Grey, Dufferin and Wellington until between 12 and 2pm. The freezing drizzle/rain may continue over the Hamilton Mountain area for a few hours lasting into the early afternoon as well. Locally higher ice accretion totals are expected here than what is expected at the bottom the higher terrain such as downtown Hamilton or Brantford. Between 10am and 1pm, the freezing rain will move into the Northern GTA region and Simcoe County. This will continue until between 3 and 6pm. All these listed areas will switch to scattered rain and/or temperatures just above zero following the freezing rain.
Over portions of the Kawartha Lakes, Peterborough and Muskoka regions, there is some questioning about the freezing line. Some models have a straight rain to snow change while others have a period of freezing rain extending from Prince Edward County towards Bancroft and Parry Sound extending south and west of this line. Therefore, we have gone with limited accretion totals over this region. Besides this, a widespread 2 to 5cm of snow can be expected from Lake Simcoe eastward towards the Ottawa region including Ottawa, Algonquin, and Cornwall.
Be sure to check out our snow/ice day forecast here and a list of school closures/bus cancellations in the morning, for those who don't have a PA day.