Updated: Apr 13, 2019
We are closely tracking a large, historic and record-breaking system weaken as it tracks near Ontario. This system has produced an ice storm with ice accretion near 0.75" and higher as well as heavy snow with 1 to 2.5 feet of snow across the Northern United States plains. As this system enters Ontario, it will bring 10-20mm of rain, locally 30mm, freezing rain with amounts between 2 to 5mm, locally higher and snowfall totals between 10 and 20cm, locally 20 to 30cm.
As the system pushes north in Ontario, moderate snowfall will begin across portions of Northwestern and Northeastern Ontario extending from Wawa through to Fort Frances, including Thunder Bay. Into the early morning hours on Friday, snow will quickly change over to freezing rain across Northeastern Ontario (Sault Ste. Marie, Elliot Lake, Chapleau). Towards the south over Manitoulin Island extending into Southwestern Ontario, along the shores of Lake Huron, a line of showers and thunderstorms will cross into the region. Further north, ice pellets will mix with snow extending from Marathon into Peterbell and Timmins, extending towards Kirkland Lake. The precipitation in this region will be scattered and spotty. Towards the north such as Hearst extending towards Nipigon to the Manitoba Border, light to moderate, at times, locally heavy snow can be expected. Around the morning hours between 5 and 9am, during the school bus commute times, light to moderate, at times, heavy snow is expected across most or all of Northwestern Ontario continuing east over areas north of Lake Superior as well as north of Hearst. Areas between Marathon and Wawa extending east towards Timmins and Hearst can expect a mix of snow and ice pellets, at times, it may switch over to freezing rain. Towards the south, freezing rain can be expected. There is the potential along the eastern shores of Lake Superior (Searchmont, Batachawana, Sault Ste. Marie) for some showers. Extending into North Bay and near Manitoulin Island, showers and local thunderstorms are possible. There is some potential for some mixing freezing rain along the Ottawa river extending from Kirkland Lake down to North Bay and Algonquin. Around noon, most of Northeastern Ontario (south of Timmins/Hearst/Wawa) can expect some showers and local thunderstorms. Further north, a thin line of freezing rain mixed with ice pellets/snow is possible. Further north towards Moosonee, Ameson and Marathon extending northwest to the Manitoba Border, light to moderate snow can be expected. Scattered showers are possible in Southern Ontario. By the early evening hours, most of Northeastern Ontario south of Marathon and Timmins should be scattered showers or clear conditions. In Southern Ontario, scattered showers are possible. Areas near or just south of Niagara/Long Point area may see some locally strong thunderstorms. As of now, the severe thunderstorm risk does remain stateside although a few storms may track over portions of Lake Erie. Back into Northern Ontario, widespread light snow is expected with moderate to heavy snow north of Hearst and Kesagami Park. By midnight (between Friday and Saturday), most of Ontario should be clear with light, scattered showers in portions of Eastern Ontario and light snow across most of Northern Ontario. Locally heavier patches of snow are possible east and northeast of Lake Superior. By Saturday afternoon, almost all the shore should end with scattered flurries across Northeastern Ontario.
The snowfall and freezing rain totals are listed for Northern and Eastern Ontario below. For rainfall, a widespread 15 to 30mm is expected in Northeastern Ontario and Southern Ontario with locally higher amounts in thunderstorms. As low as 5 to 15mm are likely for areas extending from Timmins to Wawa and for portions of Central and Eastern Ontario which miss out on most of this rain from the system.
Snowfall (and Ice Pellets)
Blue or '1':
Areas in the blue or marked with a '1' can expect less than 5cm of snow. This includes most of the central and northern portions of Northwestern Ontario and the south and central portions of Northeastern Ontario. This includes everything north and west of Kenora, Perrault Falls, Slate Falls, Summer Beaver, and Webequie. In Northeastern Ontario, this includes everything south and east of Sault Ste. Marie, Nicholson, Peterbell and Smooth Rock Falls. Areas around Smooth Rock Falls and Peterbell may locally see higher amounts between 5 to 10cm depending on the ice of transition from freezing rain/rain into or from ice pellets/snow.
Green or '2':
Areas in the green or marked with a '2' can expect between 5 and 15cm of snow. This includes areas from Morson extending towards Savant Lake, Sioux Lookout, Pickle Lake, and Vermilion Bay. Most places should see a general 5 to 10cm although we can't rule out a few places between 10 to 15cm. Further east, areas from Lake Nipigon north towards Fort Hope, Wabakimi Park, and Lansdowne House can also expect a widespread 7 to 13cm of snow. In Northeastern Ontario, areas along the between Blind River, Eillot Lake, Temiskaming Shores, and Cochrane, Peterbell and Wawa can expect a widespread 5 to 10cm, although due to lake-enhancements, pockets of 10 to 15cm are possible for areas east of Lake Superior along Highway 17 extending along Highway 101. Further north, a swath from Pukaskwa Park towards White River, Hearst, Cochrane, Fraserdale and Kesagami Park, a widespread 8 to 12cm is likely with snowfall amounts as low as 5cm where freezing rain is more dominant in this event or as higher as 15cm where ice pellets and snow are more dominant. Areas near Moose Factory and Hearst may locally see over 15cm due to a more ice pellet and snow filled system for that region although this confidence is low. Areas extending from Hearst towards White River and Pukaskwa Park may see snowfall totals as high as 20cm depending on the system track. This is unlikely, but it's worth mentioning in the 'Area of Interest'
Yellow or '3':
Areas in the yellow or marked with a '3' can expect between 10 and 20cm of snow. This includes a large swath of Far Northeastern Ontario as well as the United States-Canada border. In Northwestern Ontario, this region includes areas between Fort Frances, Atikokan, Upsala, and Nipigon, including areas south (such as Thunder Bay) and including areas north (such as Armstrong and Gull Bay). This area can expect a widespread 10cm with amounts towards 15cm in places. Over Quetico Park, along the United States border and east of Lake Nipigon, we can't rule out snowfall amounts as high as 20cm. Further east towards Beardmore, Nakina, and Marathon, a widespread 10 to 15cm is likely, locally higher amounts towards 20cm are possible. Further northeast, areas between Hornepayne, Pagwa, Ogoki, Missisa Lake, Attawapiskat, Fort Albany, and Moosonee, we can expect a widespread 15cm of snow. Local pockets towards 10cm are possible and amounts as higher as 20cm are also possible. Much of this region (Missisa Lake extending south towards Ogoki and Geraldton including Marathon and Ameson) is under the 'Area of Interest'. We have added this area into the map as there is some model guidance indicating snowfall amounts may surpass 20cm of snow. We haven't upgraded the map level due to the lower confidence in this although amounts between 20 and 25cm may be possible in this region.
Due to widespread 40 to 60, locally 70km/h wind gusts, we are expecting some significant blowing snow, especially in open areas.
Blue or '1':
Areas in the blue or marked with a '1' can expect less than 2mm of ice accretion. This includes a portion of Northeastern Ontario extending from Marathon through to Hornepayne, Smoky Falls, Hearst, Fraserdale, Kesagami Park and Moosonee. Towards the south, this also includes Manitoulin Island, Britt, Sundridge, Dorset, Bancroft, Calabogie, Renfrew, and Cobden.
Green or '2':
Areas in the green or marked with a '2' can expect between 2 and 5mm of ice accretion. In Southern Ontario, this includes Algonquin Park extending south to include Pembroke and Barry's Bay. In Northern Ontario, this includes much of Northeastern Ontario such as Mattawa, North Bay, Sudbury, Espanola, Sault Ste. Marie, Wawa, Chapleau, White River, Cochrane, Timmins, Smooth Rock Falls, Temagami, Temiskaming Shores, and Ruel. Most places should see near or slightly above 2mm although local patches towards 5mm are possible. We have added an 'Area of Interest' over the central portion of this region including Wawa, Batchawana Bay, Elliot Lake, Chapleau, Timmins, Matheson, Ruel, and Kirkland Lake. In this region, there is the potential for local ice accretion amounts between 4 and 8mm. We haven't upgraded the map level due to the low confidence but it's worth mentioning.
There is the potential for some school closures tomorrow across Northern Ontario, please check out our snow day forecast as well as the list of school regions. They can be found here.