Southern Ontario: Snowfall Outlook for Friday, December 10, 2021

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Forecast Discussion

Snowfall associated with an Alberta clipper will continue through the early part of Friday for Central and Eastern Ontario. The highest totals ranging from 2-4cm will be found along the Quebec Border and into the Ottawa Valley. Other regions will see just a trace of snow at most. The snow will come to an end quickly after sunrise as the system moves out over Quebec.

Southern Ontario: Snowfall Outlook for Thursday, December 9, 2021

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Forecast Discussion

A fast-moving system will bring some accumulating snowfall to parts of Central and Eastern Ontario during the late afternoon and evening on Thursday. General snowfall accumulation ranging from 2-4cm and maybe a few locations seeing up to 6cm is possible. Slightly more accumulation is possible along the northern shoreline of Georgian Bay where lake enhancement will boost totals. Lesser amounts further to the south with some rain mixing in near the Lake Ontario shoreline through the GTA. Eastern Ontario will continue to see snowfall lingering overnight and into Friday morning. This will be covered in a separate outlook for Friday.

Northern Ontario: Snowfall Outlook for Thursday, December 9, 2021

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Forecast Discussion

A developing system is expected to slide across Northern Ontario throughout the day on Thursday bringing with it the threat of widespread accumulating snowfall. General amounts from this system won’t be that impressive with around 6-12cm before the end of the day on Thursday. This includes locations such as Sioux Lookout, Armstrong, Fort Hope, Geraldton and Kapuskasing. However, locally higher snowfall totals are expected around the Lake Superior shoreline including Thunder Bay, Marathon and Wawa where some lake enhancement could result in accumulation reaching somewhere around 12-20cm. Blowing snow will also be an issue with 50-70km/h wind gusts particularly during the afternoon hours. Be sure to take your time out on the roads if you’re travelling in the affected regions. The heavy snowfall will affect Northeastern Ontario overnight into Friday morning which will be covered in Friday’s outlook.

Southern Ontario: Snow Squall Outlook for Wednesday, December 8, 2021

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Forecast Discussion

The snow squall threat returns to the snowbelt around Lake Huron and Georgian Bay starting Wednesday morning, but this time the focus will be on the Bruce Peninsula and into the region northeast of Georgian Bay. Organized lake effect snow and localized snow squalls will bring accumulating snow to locations such as Tobermory, Britt and Parry Sound with locally as much as 25cm by the end of Wednesday. Road conditions will be quite poor through the affected region especially during the morning and afternoon hours. The squalls should sink back southward by the dinner hour bringing a few hours of heavy snow to the Muskoka and Simcoe County region, however, accumulation will be limited due to the limited duration and disorganization.

The unusual part about this event will be that we may also see some heavy snow off Lake Ontario with the southwesterly flow pushing bands of snow into the Kingston and Brockville region. This will be primarily a concern during the morning and afternoon with general accumulation ranging from 5-15cm depending on how organized the lake effect activity can get. We may also see a few lake effect flurries through the Niagara region from Lake Erie, but accumulation will be very limited with maybe a few centimetres at most.

All snow squall activity will come to an end towards the end of the day. Lake effect flurries may linger in Thursday morning for those close to the shoreline of Lake Huron and Georgian Bay.

Northern Ontario: Snow Squall Outlook for Tuesday, December 7, 2021

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Forecast Discussion

Snow squalls are expected to organize off the eastern shoreline of Lake Huron between Wawa and Sault Ste. Marie starting early Tuesday morning. The squalls will continue throughout the day where the worst conditions are likely to be found during the afternoon and evening as the squalls intensify into one strong squall setting up somewhere near Agawa Bay. In the strongest part of the squall, we could be looking at snowfall rates around 5-10cm per hour so rapid accumulation is likely. Travel will be significantly impacted between Wawa and Sault Ste. Marie especially along the Trans-Canada Hwy which may need to be shut down. Total accumulation may locally approach the 50cm mark in this region with general amounts between 15-30cm for Sault Ste. Marie and Wawa. The snow squall activity will weaken late Tuesday and into Wednesday morning.

Southern Ontario: Snow Squall Outlook for Monday, December 6 to Tuesday, December 7, 2021

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Forecast Discussion

After a brief warm-up during the early part of Monday, a cold front will sweep across the region during the afternoon and evening hours which will usher in colder air. This colder air will help restart the lake effect snow machine throughout the typical snowbelt around Lake Huron and Georgian Bay starting late Monday evening. The primary targets of these snow squalls will be the Bruce Penisula through Simcoe County and into parts of Kawartha Lakes.

Current indications suggest a fairly intense squall will set up from just north of Wiarton and come inland across Georgian Bay between Orillia and Barrie and could remain nearly stationary overnight and into Tuesday morning for over 12 hours. This band could stretch quite far inland making it as far east as Peterborough at times. Snow squall activity will continue throughout the day on Tuesday with an additional 5-15cm of snowfall accumulation expected. However, it will likely become a lot less organized as we go throughout the day so the majority of the accumulation will come Monday night into Tuesday morning. The snow squalls will drift northward towards the Parry Sound/Huntsville area late Tuesday as the wind direction shifts to a more southwesterly flow.

With hourly snowfall rates approaching 3-6cm, it will pile up quite quickly and wouldn’t be surprised to see a few locations come near 30-40cm by the end of Tuesday. There is even the potential for very localized totals up to 50cm as some models have shown, but this seems a little overdone in the model data. More general snowfall totals will range from 15-30cm throughout the region. Keep in mind that just because you’re in the heaviest accumulation zone doesn’t mean you will get it as snow squalls are a very localized event. We’ve tried our best to narrow it down as much as possible, but just a slight shift in the wind direction can dramatically change who sees 40cm and 0cm from this squall event. Travel conditions will likely be very hazardous throughout the affected region. If you can, avoid travel until later in the day on Tuesday when conditions will improve somewhat.

Northern Ontario: Snow Squall Outlook for Saturday, December 4, 2021

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Forecast Discussion

Snow squalls are expected to develop early Saturday morning east of Lake Superior and continue throughout the day. This will bring rapid snowfall accumulation and near-zero visibility to the Wawa and Sault Ste. Marie area. Accumulation by the end of Saturday could locally approach the 20-25cm mark with more general amounts between 10-20cm. The snow squall activity will come to an end late Saturday as an approaching winter storm shuts off the lake effect snow. More details on that winter storm are coming soon.

Southern Ontario: Snow Squall Outlook for Saturday, December 4, 2021

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Forecast Discussion

Disorganized lake effect snow is expected to develop off Georgian Bay starting Saturday morning and will further organize into stronger snow squalls later in the day. The bands will initially favour a southwesterly flow which would put the Parry Sound, Britt and Huntsville area in the heaviest snowfall rates during the early part of Saturday. However, this lake effect snow will quickly sink southward towards the Midland, Bracebridge and Orillia area by the afternoon with more organized squall activity developing. This will allow for some rapid snowfall accumulation with the worst conditions expected late afternoon and into the evening hours.

There is still some uncertainty in regards to the placement of the squall where it could end up stalling as far north as Bracebridge and as far south as Orillia. Somewhere in this corridor, we expect to see the potential for up to 25cm of accumulation by the end of Saturday. The Bruce Peninsula will also be affected by these squalls with the highest totals found around the Tobermory area. As is typical with these events, it’s important to emphasize that just because we’re saying that certain regions could see up to 25cm doesn’t guarantee they’ll see significant snowfall accumulation. It just depends on where the squall sets up and the intensity which can be quite hard to predict.

The squall could stretch quite far inland at times and may affect the Northern Kawartha Lakes region and even northern parts of Peterborough county. Accumulation here has the potential to reach up to 5-15cm. Southern parts of Simcoe County such as Collingwood and Barrie should escape the worse. Although it’s possible they see some brief snow squall activity with up to 5-15cm of snow possible. Surrounding regions will see up to 5cm with scattered lake effect flurries, but not much impact is expected. The snow squall activity should come to an end just after midnight and early Sunday morning as an approaching winter storm shuts off the lake effect snow machine. More details on that winter storm that will affect parts of Southern and Northeastern Ontario starting Sunday afternoon are coming soon.