We are currently watching a significant winter storm as it crossed into Ontario throughout the day on Sunday, lasting through to Monday and some lingering affects into Tuesday morning. Behind the system, bursts of snow and lake-effect snow will create some at-times hazardous driving conditions.
Areas in the red and marked with a '5' can expect ice accretion totals between 15 and 20mm with pockets towards 25mm or 1 inch. This includes Lake Superior Park, Agawa Bay, Montreal River Harbour, Batchawana Bay, Harmony Beach, Heyden and areas along the shores of Lake Superior. Freezing rain totals will average near 14-18mm with pockets of 18-26mm in the higher terrain and rural areas. This includes areas west of Heyden, north of Batchawana Bay, and east of Lake Superior Park. Thankfully, most of these areas are rural with no towns or cities.
Areas in the orange and marked with a '4' can expect ice accretion totals between 10 and 15mm. In Northern Ontario, this includes Michipicoten, Anjigami, Pineal Lake, Ranger Lake, Sault Ste. Marie, St. Joseph Island, Thessalon, and Blind River. A majority of these areas will see between 13-16mm of ice with local pockets towards 20mm for areas north of Sault Ste. Marie, and north of St. Joseph Island. In Southern Ontario, this region includes two separate areas. In Central/Eastern Ontario, this area extends from Huntsville and Bracebridge through to Haliburton, Minden Bancroft, Kaladar, Sharbot Lake, Smiths Falls, and Brockville. These areas can expect an average of 12-14mm of ice accretion with locally less near 10mm towards the New York Border and locally more towards 16-18mm between Haliburton-Bancroft-Sharbot Lake. The final area extends from Collingwood south towards Shelburne and Orangeville where 8-14mm can be expected.
Areas in the yellow and marked with a '3' can expect ice accretion totals between 5 and 10mm. Areas between Kingston to Peterborough, Orillia, Uxbridge, Barrie, and Midland can expect totals amounts between 8-12mm. Areas towards Southwestern Ontario including Bond Head, Caledon, Flesherton, and the Blue Mountains can expect ice accretion totals towards 5-8mm. Towards Northern Ontario, areas between Gravenhurst, Burk's Falls, French River, North Bay, Trout Creek, and Dokis can expect freezing rain totals also in the 5-8mm range. Towards Eastern Ontario including Cornwall, Kemptville, Carleton Place, Denbigh, and Maynooth, there is some uncertainty as to how much precipitation will fall as ice pellets of freezing rain. These areas are likely to see a near 5mm of ice accretion before ice pellets take over although locally higher totals are possible. In Northern Ontario, freezing rain totals will range between 6 and 12mm from Northern Manitoulin Island and Espanola, through to Elliot Lake, portions of Mississagi River Park, Chapleau, Wawa, and portions of Pukaskwa Park. Areas closest towards Elliot Lake and Wawa may see local pockets between 12 and 14mm.
Areas in the green and marked with a '2' can expect ice accretion totals between 2 and 5mm. In Northern Ontario, this includes White River, Gogama, Cobalt, Temagami, Thorne, Sudbury, a majority of Manitoulin Island, and Mattawa. Freezing precipitation will switch from a drizzle to a rainfall, therefore amounts will vary between 2 and 4mm with pockets of up to 6mm closer towards Dubreuilville, Sudbury, and Manitoulin Island. This also includes Parry Sound and Britt. In Eastern Ontario, this includes a majority of Algonquin Park, Pembroke, Barry's Bay, Ottawa, Hawkesbury, and Renfrew. In these areas, freezing rain totals between 2 and 3mm are likely with pockets near 1mm and up to 5mm depending on how long the freezing rain lasts before changing to ice pellets across the region. In Southwestern Ontario, this includes Meaford through to Markdale, Guelph, Newmarket, Bradford, Whitby, Cobourg, Brighton, and Belleville. A majority of the region will see between 2-4mm of ice with less towards the shores of Lake Ontario and locally more towards the yellow (3) region. The areas which may see locally more include Bradford and Belleville where pockets towards 4-6mm may be possible.
Areas in the blue and marked with a '1' can expect ice accretion totals under 2mm. This includes the shores of Lake Ontario such as Oshawa, Picton, Sandbanks Park, and Ajax were a drizzle is possible. Areas across Vaughan, Markham, Brampton, Kitchener, Mount Forest, Dundalk, and Balaclava can expect freezing rain totals between a drizzle and 1mm with the most towards Grey County between Dundalk and Balaclava. This also includes Englehart, Foleyet, Marathon, and Terrace Bay. If the warm air can push slightly further north, which is possible, than areas such as Kirkland Lake and Timmins also may see a drizzle.
Areas in the pink and marked with a '6' can expect snowfall totals between 30 and 50cm. In Northwestern Ontario, this includes Pigeon River, Cloud Bay, and Neebing. The snow will be moderate to heavy at times and could briefly mix with ice pellets. The snowfall totals are based on the snow throughout the day on Sunday, Monday, and Tuesday.
Areas in the red and marked with a '5' can expect snowfall totals between 15 and 30cm. This includes a large portion of Northern Ontario for areas north of Lake Superior. This includes Atikokan through to Upsala, Raith, Thunder Bay, Terrace Bay, Nipigon, Beardmore, Longlacc, Hornepayne, and Manitouwadge. Snowfall totals will average between 15 and 25cm with pockets towards 30cm closest to Lake Superior and Lake Nipigon such as Nipigon, Terrace Bay, and Thunder Bay. Isolated pockets towards 40cm are even possible throughout this region with the best risk towards Kakabeka Falls through to Suomi, and Matawin River Nature Reserve.
Areas in the orange and marked with a '4' can expect snowfall totals between 15 and 30cm. This includes a large portion of Northern Ontario extending from Fort Frances and Nestor Falls through to Ignace, Kowkash, Pagwa, Hearst, Kapuskasing, White River, and Dubreuilville. Snowfall totals will average between 15 and 20cm with pockets towards 30cm closest to Lake Nipigon through to Fort Frances as well as towards Hearst and White River.
Areas in the yellow and marked with a '3' can expect snowfall totals between 10 and 20cm. This includes a wide area of Northern Ontario. In Northwestern Ontario, snowfall totals between 10 and 15cm are possible from Kenora and Grassy Narrows towards Dryden, Sioux Lookout, Savant Lake and Armstrong. Amounts will average near 10cm across this region with up to 15cm closer towards Armstrong. Isolated pockets of 20cm are possible between Armstrong and Lake Nipigon. In Northeastern Ontario, this includes Mammamattawa, Otter Rapids, Smooth Rock Falls, Timmins, Matheson, Kirkland Lake, and Foleyet. In these areas, snowfall totals closest to 10cm are likely with pockets up to 15cm. Areas further south towards Wawa, Agawa Bay, Chapleau, Gogama, Cobalt, and Temagami can expect snowfall totals near 10cm. At times, the snow may mix with ice pellets. In Southern Ontario, this includes Hawkesbury and Vankleek Hill. Snowfall totals near 10cm are likely with pockets of 15cm along the Quebec border.
Areas in green and marked with a '2' can expect snowfall totals between 5 and 10cm. In Northern Ontario, this ranges from between Perrault Falls and Red Lake through to Osnaburgh House, Ogoki Lake Park, Moosonee, Onakawana, and Kesagami Park. Snowfall totals will average near 5cm although pockets of near 10cm are likely closer towards Kesagami Park. Towards the south, snowfall totals between 5 and 10cm are likely from Montreal River Harbour through to Ranger Lake, Sudbury, North Bay, and Thorne. Areas closest towards Lake Superior who receive more freezing rain will see near 5cm of snow while areas further inland towards Thorne and Sudbury will see totals between 5 and 10cm. Pockets of 10-14cm are possible due to mixing ice pellets across this region. In Southern Ontario, this includes Cornwall, Kemptville, Ottawa, Spotswood, and Alexandria. Snowfall totals will range between 5 and 10cm with mixing ice pellets. Pockets up to 15cm are possible towards Ottawa and Alexandria, although unexpected at this time.
Areas in the blue and marked with a '1' can expect snowfall totals near or under 5cm. This includes a large portion of Central and Eastern Ontario as the rain and freezing rain switch over to snow Monday night into Tuesday. Snowfall totals will average under 3cm with a trace at most. Pockets of 3-5cm are most likely towards the east in the 'Area of Interest'. This includes Sault Ste. Marie, Espanola, Algonquin Park, Barry's Bay, Smiths Falls, and Pembroke. If ice pellets are the primary precipitation type further west, this area of interest will also move west.
Heavy snow in bursts and lake-effect are possible across most of the province surrounding the Great Lakes on Tuesday into Wednesday. We will have a separate forecast for this snowfall event.
Thunderstorms and Rainfall:
Areas in the yellow and marked with a '3' can expect rainfall totals between 15 and 30mm. This includes the shores of Lake Ontario into Toronto extending down to Oakville and Hamilton as well as Essex County, the Chatham region, Elgin County, Norfolk and Haldimand Counties and much of Brant County, including Brantford. This also includes the Niagara region. Isolated pockets near 40mm are possible in this region. Isolated thunderstorms are possible across this region.
Areas in the green and marked with a '2' can expect rainfall totals between 15 and 30mm. This includes much of Southwestern Ontario including Picton and Sandbanks through to Peterborough, Orillia, Parry Sound, Barry, Newmarket, Manitoulin Island, Owen Sound, Goderich, Sarnia, and Kitchener. Rainfall totals will be highest for areas away from the freezing rain. Areas such as Manitoulin Island, Parry Sound, Orillia, Barrie, Midland, Peterborough and Kingston may only see up to 15mm. Isolated thunderstorms are possible across this region including areas that may see freezing rain. Thunderice...may be possible.
Areas in the blue and marked with a '1' can expect less than 15mm of rain. This includes the Dundalk Highlands towards Shelburne and Orangeville as well as the shores of the North Channel towards Sault Ste. Marie. This also extends into Central and Eastern Ontario from Smiths Falls through to Sharbot Lake, Bancroft, Huntsville, Brockville, and Haliburton. Isolated thunderstorms are possible towards Shelburne and Orangeville. Thunderice...may be possible.
The strongest winds will sit over the shores of Lake Superior extending towards Parry Sound and for areas east of Lake Huron. These winds will range from 40-70km/h. This may cause widespread power outages along the eastern shores of Lake Superior and scattered outages across the North Channel extending into Britt, Burk's Falls, and Haliburton as well as the Shelburne and Orangeville regions as winds towards 30-60km/h are possible. Due to the lack of strong winds with average readings between 25 and 45km/h, power outages are likely and expected across Eastern Ontario between Bancroft-Smiths Falls-Brockville-Peterborough, but the majority of the outages will NOT be prolonged.
We will update our forecast as needed as this event begins to take place.