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Widespread Snow and Lake Effect Snow to Impact Southern Ontario

After a snowstorm and road closures in Northern Ontario with an ice storm in Southern Ontario, this system is pulling away with cooling temperatures and some lake-enhanced snowfall across Southern Ontario.

Snowfall Forecast, for Southern Ontario. Issued December 31st, 2019.
Snowfall Forecast, for Southern Ontario. Issued December 31st, 2019.

The snow will be light to moderate across much of the region with pockets of moderate to heavy snow, especially for areas surrounding Lake Huron. At times the snow may be heavy for portions of Southern Ontario outside of the snowbelt such as Toronto or into Eastern Ontario. The system will move through the region throughout the morning and afternoon on Tuesday before some weak to moderate lake-effect snow sets up across the snowbelts. These will be weak and 'break off' at times sending small pockets of snow eastward towards the GTA and Central Ontario. Due to gusty winds between 40 and 60km/h, blowing snow is possible and visibility drops to near 0 are also possible.

The hardest-hit areas will be along the shores of Lake Huron impacting portions of Highway 21, 9, 4, and 86. Careful travelling as it may go from clear to a period of reduced visibility in a matter of minutes.


Areas in the orange and marked with a '4' can expect snowfall totals between 10 and 15cm. This includes two main regions. The first region is within the snowbelts across Southwestern Ontario. This includes areas east of Lake Huron and south of Georgian Bay. Areas along the shores of Lake Huron such as Port Elgin, Kincardine, and Goderich can expect between peak snowfall totals near 10cm with pockets even below this range between 6 and 10cm, due to the above temperatures of Lake Huron. Areas further inland between 15 and 25km can expect to be within the 12-16cm range with pockets near 20cm. This includes Clinton, Seaforth, Blyth, St. Helens, Lucknow, Kinlough, and Chepstow. The best risk of totals near or over 20cm will be around the Lucknow-Dungannon-Kinlough region. Areas elsewhere in this region will see a general 10-14cm with pockets between 14 and 16cm. This includes Hensall, Mitchell, Brussels, Wingham, Teeswater, Paisley, Tara, Owen Sound, Meaford, Blue Mountains, Rocklyn, and Holland Centre. Areas near Owen Sound and Kilsyth may range just at or below the snowfall totals for this region with totals between 9 and 12cm. In Eastern Ontario, snowfall totals between 12 and 16cm are likely near Hawkesbury and Wendover. Local snowfall totals near 20cm are possible. This snowfall is also expected into Quebec so travel should be monitored in this region. If the heaviest bands do linger slightly towards the south, Ottawa and nearby regions may see a slight increase to the snowfall totals with the localized totals (for the yellow or '3' region) more likely.

Areas in the yellow and marked with a '3' can expect snowfall totals between 8 and 12cm. In Southwestern Ontario, this includes portions of the Bruce Peninsula near Lion's Head and Tobermory as well as areas east of Lake Huron. This includes Grand Bend, Bayfield, Lucan, Thorndale, St. Marys, Stratford, Milverton, Listowel, Hanover, St. Jacobs, Arthur, Mount Forest, Flesherton, and Williamsford. The average snowfall across this area will range near 10cm with pockets towards 12-14cm where heavy lake-effect moves through while pockets towards 8-10cm are likely for areas which are in a 'dry-slow' of the lake-effect core bands. Areas in the 'area of interest' towards Midland, Orillia, Minden, MacTier, and Gravenhurst, there is some model disagree as to whether or not lake-effect snow will develop across this region. If this does happen, snowfall totals will be increased from what the map displayed with expected totals in the 10-15cm range and local pockets towards 20cm. If the bands do not happen, snowfall totals near 8-10cm are most likely with pockets between 10 and 14cm. Areas further east into Central and Eastern Ontario for areas north of Peterborough as well as near and between Bancroft, Sharbot Lake, Pembroke, Arnprior, Renfrew, Smiths Falls, Tweed, Lanark, and Clyde Forks, snowfall totals will average near 10cm. Pockets of 8cm are most likely towards Peterborough and near Pembroke with pockets near 12cm likely near Sharbot Lake and Clyde Forks. Into Far Eastern Ontario, snowfall totals near 10cm are likely with pockets towards 12cm closer towards Ottawa and Alexandria. This includes Kemptville, Richmond, and Casselman.


Areas in the green and marked with a '2' can expect snowfall totals between 4 and 8cm. This includes much of Southern Ontario. In Extreme Southern Ontario, this extends from Essex County through Chatham, Lambton, Middlesex, Elgin, Oxford, Brant, Norfolk, Haldimand, Wellington, Waterloo, and into Dufferin. Across this region, snowfall totals will average near 4-5cm. Areas between St. Thomas, London, Delhi, Woodstock, Brantford, Kitchener, and Shelburne may see totals closer towards 6 and even 8cm. Isolated pockets of 10cm are also possible. Towards the Niagara region, snowfall totals in the south will range between 3-4cm with pockets of 4-8cm towards Fort Erie. This area is highlighted in an 'area of interest.' If a more intense lake-effect snow band does set up over this region, snowfall totals may be enhanced towards 10cm. Areas near Collingwood may see near 4-5cm with the potential for even less towards 2-3cm. In the GTA, areas from Barrie through to Oshawa will likely see near 5cm of snow. Pockets of 5-8cm are likely closest towards Oshawa and Uxbridge. Areas near Peterborough will see between 3-6cm. Into Eastern Ontario, areas such as Cornwall, Brockville, Westport, and Piccadilly will likely see near 5-8cm of snow. Pockets closer towards 10cm are possible with localized areas seeing between 10 and 14cm. This is most likely for areas between Kingston and Smiths Falls as well as between Bellville and Sharbot Lake. In Northern Ontario and portions of Central and Eastern Ontario, snowfall totals will average near 6cm across Algonquin Park into Northwestern Renfrew and much of Muskoka. Snowfall totals will be less towards the north near Mattawa and Britt and more towards the south near Barry's Bay and Parry Sound. Totals will range quite a bit with some underachieving near 2-4cm while others overachieve towards 10cm. Into Northern Ontario, snowfall totals between 3-6cm are likely with pockets of 6-9cm likely from Espanola towards Sault Ste. Marie along the northern shores of the North Channel. A snow band may briefly setup from between Killarney and Key Harbour and push northeast towards Sudbury. Locally higher amounts near 10cm are possible across this band.

Areas in the blue and marked with a '1' can expect snowfall totals between a trace and 4cm. This includes a few areas in the region. The first region is in the Extreme South near Windsor, Amherstburg, and Pelee Island. Snowfall totals across this area will average between 2-3cm. Into the GTA. snowfall totals between 2-4cm are likely across Toronto and the surrounding cities with local pockets towards 4-6cm. This region extends around the western shores of Lake Ontario extending towards Hamilton, Grimsby, and Niagara-on-the-Lake. This also extends north along Highway 400 towards, but not including Barrie towards the west as well. The third region is across Prince Edward County including Sandbanks and Picton. Snowfall totals near or under 2cm are most likely here. Finally, into Northern Ontario, snowfall totals will range from 2-4cm near Trout Creek, Temagami, and North Bay through to Montreal River Harbour, Agawa Bay, and Chapleau with localized pockets near 4-8cm for the shores of Lake Superior.


This will be our last forecast of 2019 and first forecast in 2020. From everyone at Weather Watch, we want to wish everyone a happy new year. If anyone has plans this evening, we hope that your travels are safe.

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