We are tracking what is set to be one of the biggest snowstorm this winter across Southern Ontario with a widespread 10-20cm expected with amounts closer to 40cm possible across Eastern Ontario. A significant snow squall outbreak is possible after this system spanning from Thursday through tot he weekend.
NOTICE: Updates to this forecast may be required and will be occur if needed.
Snowfall, system timing, and information about the winds can be found throughout the article below.
The system will begin to push into the province between 8pm on Tuesday and 12am on Wednesday across the Extreme South throughout Essex County and the Chatham region before moving into Lambton and Western Elgin Counties closer to midnight or 1am. This is highlighted in blue and marked with a '1'.
The system will continue to push across the region into the morning hours between 1am and 6am with some scattered flurries beginning in Lambton-Elgin-Middlesex as they move across Lake Erie and into Southwestern Ontario towards Huron-Perth, Waterloo-Wellington, the Niagara region, and the Southern GTA. Snow should be light and have minor impacts. Nearing 6am, snow may push slightly further north towards Dufferin and Grey Counties, as well as the city of Toronto, although this may be delayed by 1-2 hours. This timeframe is highlighted in green and marked with a '2'.
The system will continue to push north in the morning as it gains strength. As it pushes across Huron-Perth-Wellington as it pushes into Grey-Bruce, Dufferin, and Central and Northern GTA, and along the 401 towards Belleville and Prince Edward County, moderate snow will begin to push into Essex County as the light and scattered flurries continue north. The snow will begin to intensify further into the this timeframe. This timeframe is highlighted in yellow and marked with a '3'.
Into the afternoon, light snow will begin to fill in across Central and Eastern Ontario spanning to the Quebec border by the evening rush hour. Moderate to possibly heavy snow will begin to push across Lambton-Middlesex further north as well as across the Niagara region extending into Toronto and the GTA. There is a slight risk of some heavier snowfall rates just south of Lake Ontario in the Northern Niagara region due to some minor lake enhancement although this is unknown. Some minor freezing rain or rain may also push into the Niagara region towards Fort Erie, although it questionable whether cold air will 'win' out in this situation and reduce this risk. Areas closer towards Peterborough and Orillia may see it start slightly early just before noon. This timeframe is highlighted in orange and marked with a '4'.
Into the evening, moderate to at times heavy snow will push across much of Eastern Ontario spanning from Kingston through to Algonquin and Ottawa. Some locally moderate snowfall is also possible to the lee of Lake Huron across Huron-Bruce Counties. Brief rain showers and some freezing rain may be possible over Southern Niagara from Niagara Falls to Fort Erie as well as over Prince Edward County, possibly extending into Southern Kingston along the water. Brief freezing rain may be possible along the St. Lawrence River towards Brockville, although cold air appears to overtake much of the region limiting the icing risk. Light snow will continue to advance north into the Algonquin and Parry Sound regions. This timeframe is highlighted in orange and marked with a '5'.
By the early morning hours near 1am, moderate to heavy snow located between the GTA and Kingston is expected to develop and continue northeast towards Central-Eastern Ontario with heavy snowfall rates of multiple centimetres per hour. Hazardous travel is expected. Rain may mix it at times across Prince Edward County. Light to moderate snow will slowly come to an end across Southwestern Ontario beginning near Windsor and Sarnia.
Into the morning hours (4-8am) on Thursday, heavy snow creating whiteout conditions, at times possibly blizzard conditions, may develop across Central and Eastern Ontario from Prince Edward County and Kingston in a burst northward to the Quebec border between Pembroke and Ottawa. The band may produce rates up to and past 5cm an hour and span from Algonquin Park through to Montreal. Scattered flurries will start to end across Southwestern Ontario. Lake-effect will begin to develop off Georgian Bay and Lake Huron throughout the morning before intensifying into the evening.
Into the afternoon on Thursday, heavy and moderate snow will linger across Algonquin Park while flurries begin to develop across Central and Eastern Ontario with ramping up lake effect.
Into the evening on Thursday, snow squalls will be in full force on Thursday off of Lake Huron and Georgian Bay as lingering flurries creating blowing and drifting snow across Eastern and Central Ontario. A separate forecast will be issued tomorrow stating the snow squall impacts.
System Snowfall Forecast
Areas in the pink and marked with a '6' can expect snowfall totals between 25cm and 35cm with local amounts over 35cm. This region includes most of Algonquin Park extending along the Quebec border into Pembroke and Renfrew as well as Barry's Bay and Bancroft. Snowfall totals will average near 30cm although amounts certainly up to 40cm are possible, especially near the Quebec border. Isolated totals over 40cm may be possible.
Areas in the red and marked with a '5' can expect snowfall totals between 20 and 30cm. This region extends from the Quebec border near Hawkesbury extending through to Ottawa, Carleton Place, Sharbot Lake into the Kawartha Highlands Provincial Park and Peterborough regions. This region also extends from the Kawartha Lakes through to Dorset and Mattawa. Snowfall totals will average near 25cm with lower amounts towards Peterborough and Sharbot Lake and higher amounts towards Ottawa and Haliburton.
Snowfall totals may overachieve between Sharbot Lake and Ottawa and may reach amounts between 30cm and 35cm. Areas towards the north near Mattawa will be on a dividing line between a foot of snow (30cm) and amounts towards 20cm. A slight shift could greatly change how much snow falls in this area.
Snowfall amounts in the red may exceed 35cm with ending totals closer to 40cm.
Areas in the orange and marked with a '4' can expect snowfall totals between 15 and 25cm. This extends from the Quebec border near Alexandria extending through to Smiths Falls and Belleville including areas just south of Kaladar and Peterborough. Amounts in this region are expected to range near 20cm with 25cm expected closer to the red (5) region. Snowfall may be limited due to some minor freezing rain mixing in at times towards Belleville. Amounts in this region would be limited to 15 to 20cm.
Areas further west including portions Western Toronto, around Lake Simcoe, Simcoe County, and extending into the Muskoka region through to Huntsville, Burk's Falls, and Powassan, snowfall totals near 25cm are expected. Amounts may range higher or lower depending on the exact location with less towards the north and more closer to the red (5) region. Amounts up to and possibly exceeding 30cm are possible over portions of this area, closer towards North Bay and Huntsville. Areas around Georgian Bay extending from Meaford and Collingwood through to Barrie, Midland, and Gravenhurst may see some brief lake-enhancement. Amounts may be pushed between 20 and 25cm across this region. The higher terrain just south of Georgian Bay may see local amounts towards 30cm.
Areas in yellow and marked with a '3' can expect snowfall totals between 10 and 20cm. In Eastern Ontario, this extends along the United States border where freezing rain, and possibly rain, may mix in with snowfall. Totals across the region between 10 and 15cm are most likely with more towards the north and closer to the low end of the scale near the border and Prince Edward County. Areas north of Kingston through to Belleville may see local amounts over 15cm towards 20cm.
In Southwestern Ontario, areas between Toronto and Woodstock extending into Goderich, Kincardine, and Owen Sound, including Wellington, Perth, Huron, Dufferin, and Southern Grey County, snowfall amounts near 15cm are likely. Amounts will vary with intensity with amounts closer to 20cm possible to the lee of Lake Huron and into the GTA with amounts closer to 10cm likely in the center from Stratford through to Woodstock and Brantford and towards the north near Owen Sound.
Towards the south including Sarnia and Windsor extending into Chatham, and London, snowfall amounts between 10 and 15cm are most likely. Into the Golden Horseshoe, areas in Hamilton, Dunnville and the Niagara region can expect amounts near 15cm. Amounts will be lowest towards 10cm near the shores of Lake Erie with local amounts near 20cm into the higher terrain near Hamilton and just south of Lake Ontario near Grimsby.
Into the north across the Bruce Peninsula extending into Parry Sound and Britt, snowfall totals between 15cm to 20cm are expected. This also includes places near Northern Grey County including Owen Sound. Local amounts across this region may exceed 20cm towards the 25cm range.
In the area, areas across West Nipissing through to Temgami, and Kirkland Lake may see between 20 and 25cm of snow with local amounts possibly up to 30cm along the Quebec border. Further north, snowfall totals between 15 and 20cm are possible into Timmins and Little Abitibi extending towards the Moosonee region. Snowfall amounts up to 25cm may be locally possible.
Areas in green and marked with a '2' can expect snowfall totals between 5 and 10cm. In Southern Ontario, this includes the shores of Lake Erie over Pelee Island, Rondeau Park, towards Duttona Beach, Long Point, and into the Fort Erie region as rain and/or ice may mix into the region. Amounts certainly could pass 10cm into the 15cm range if colder air remains and the warmer air remains south of the region. This also includes the southern part of Prince Edward County on the shores of Lake Ontario.
Into Northern Ontario, this includes Manitoulin Island through to Sudbury and Gogama extending into the Hearst and Fraserdale regions where amounts between 5 and 10cm are possible. Local amounts up to 15cm are possible across Manitoulin Island towards Britt.
Finally, areas in the blue and marked with a '1' can expect snowfall totals between a trace and 5cm. This includes a large portion of Northeastern Ontario from Lake Superior through to Espanola and Gogama where amounts may peak near 5cm towards the east. A general trace to 2cm is expected across much of this region.
System Wind Forecast
Winds will slowly increase throughout the day as the centre of the low approaches the area. Winds in the morning across Southern Ontario will range between 15 and 30km/h with wind gusts increasing to 30-45km/h (locally 50km/h) into the evening. Blowing and drifting snow will be a large concern.
As the system approaches, wind gusts into the morning could reach between 60 to 70km/h across most of Southern Ontario with gusts between 50 and 65km/h up near Algonquin Park. Widespread blowing snow creating whiteouts and possibly blizzard-like conditions will be possible as the heavy snow bands begin to move across the region. Areas closer to Lake Ontario may see wind gusts closer to 80km/h.
Into the afternoon and evening, wind gusts between 60 and 80km/h will be possible across Southern Ontario with amounts closer to 90km/h possible over Prince Edward County. Widespread blowing and drifting snow can be expected. Hazardous travel is possible and expected. Widespread hazardous conditions across Eastern Ontario from the higher snowfall totals will create travel issues.
Squalls - Updated Forecast to Come
Across Southwestern Ontario, wind gusts between 60 and 70km/h in an NW-W flow will create widespread snow squalls off of Lake Huron and Georgian Bay. Blizzard conditions and rapid snowfall with rates between 5 and 10cm/h will be possible. Snowfall totals from these squalls may add another 30-60cm+ onto the system snowfall described above. There will be a complete snowfall forecast for the squalls which should last from Thursday night into Saturday evening out later this week so stay aware of that. These will be very intense snow squalls with thundersnow possible as well. Prepare now and take note that essential-only travel should be concerned later this week.
School Closures and Road Closures
We will be issuing daily snow day forecasts for Wednesday, Thursday and Friday each night between 10pm and 1am. These can be found here. Widespread school closures are expected on Thursday with school closures likely in the snow belts on Friday. It is possible that there is scattered school closures on Wednesday as well.