Northern Ontario: Fall Weather Hazards Outlook for Thursday, November 18, 2021

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Forecast Discussion

Snow squalls are possible off the Eastern shoreline of Lake Superior starting early Thursday morning and continuing throughout the day. The heaviest snowfall rates will be found between Sault Ste. Marie and Wawa where travel conditions will be quite poor during the morning and afternoon with near-zero visibility. We expect to see the squalls will slowly weaken by late Thursday and be fully done around the midnight hour.

Total accumulation in the hardest hit zone including Wawa and just to the north of Sault Ste Marie could approach up to 20cm with general amounts between 10-20cm. Surrounding areas that include Marathon, Chapleau and Sault Ste. Marie can expect locally up to 5-10cm by the end of the day although not everyone will see even a flake of snow due to the localized nature of lake effect snow.

Southern Ontario: Fall Weather Hazards Outlook for Thursday, November 18, 2021

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Forecast Discussion

The lake effect machine will kick back into gear to end off the week for Thursday and affect areas mainly to the east of Georgian Bay. We will see the development of lake effect snow beginning Thursday afternoon around the Parry Sound and Muskoka region. Although they won’t really get organized until after the dinner hour when some localized strong squalls may develop and continue into the overnight hours. A few hours of heavy snow is possible through the Hwy 400 and Hwy 11 corridor between Parry Sound to Honey Harbor and Huntsville to Gravenhurst with poor travel conditions during the evening.

Localized totals of up to 15cm can’t be ruled out should the squall lock into a particular area for a few hours. A more general estimate would be around 5-10cm, but it’s hard to predict as these squalls are so localized. There will also be some less organized activity off Lake Huron that will bring around 5cm at most with locally up to 10cm for the Hanover and Meaford area.

The wind direction will shift bringing the weakening squall southward into parts of Simcoe County and Kincardine/Listowel area early Friday morning. They will fully dissipate by late Friday morning so accumulation should be limited on Friday.

Northern Ontario: Fall Weather Hazards Outlook for Wednesday, November 17, 2021

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Forecast Discussion

A system that has been bringing heavy snow to parts of Northwestern Ontario will start to move into Northeastern Ontario where there is the risk of freezing rain. This will begin early Wednesday morning with the heaviest ice accretion found along the Quebec border from North Bay to Cochrane. They may pick up to 6mm of ice accretion. The freezing rain could make for some slippery driving conditions for the Wednesday morning commute in the area. Be sure to drive with caution. Some isolated power outages can’t be ruled out, but it’s unlikely given the limited ice accretion expected. Conditions will improve by late Wednesday as warmer air flows into the region. Snow will also continue for other parts of Northern Ontario, please see our special outlook for more details here.

Southern Ontario: Fall Weather Hazards Outlook for Wednesday, November 17, 2021

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Forecast Discussion

Precipitation associated with a system expected to bring significant snowfall accumulation will push through the northern section of Southern Ontario early Wednesday and continue into the afternoon. For the higher elevations along the Quebec border including North Bay, Algonquin Park and Petawawa, we could be looking at several hours of freezing rain mainly during the morning hours and transitioning over to regular rain later in the day as temperatures slowly rise above the freezing mark. Up to 6mm of ice accretion is possible within this zone.

In other areas including the Ottawa Valley, Bancroft, Sundridge and Sudbury there is the risk for some freezing drizzle before the switch over to rain happens although impacts will be minimal. This freezing rain could make for some slippery driving conditions for the Wednesday morning commute in the area. Be sure to drive with caution. Some isolated power outages can’t be ruled out, but it’s unlikely given the limited ice accretion expected. Conditions will improve by late Wednesday as warmer air flows into the region.

Southern Ontario: Fall Weather Hazards Outlook for Saturday, November 13, 2021

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Forecast Discussion

After a brief period of mild weather across Southern Ontario the past week that brought double-digit temperatures, winter will make its return this weekend. This will begin with some lake effect flurries around Lake Huron and Georgian Bay along with northeast of Lake Erie into the Niagara region. The flurries will begin early Saturday morning and continue throughout the day. More snow is expected late Sunday into Monday as a system brings what could be the season’s first widespread snowfall for Southern Ontario. Accumulation on Saturday is expected to be fairly minor with most areas just seeing a dusting of snow if anything at all. A few locations may pick up close to 5cm or locally more should a strong snow streamer gets organized enough. Due to the nature of lake effect snow, you should be prepared for a rapid reduction in visibility so be sure to drive according to the conditions.