Impactful Christmas Winter Storm To Deliver Up to 10-20cm of Snow or Prolonged Freezing Rain to Northern Ontario Between Friday and Saturday

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It won’t be quite the joyful Christmas across Northern Ontario when it comes to the weather as a messy winter storm is expected to move through the region beginning Christmas Eve and continuing into Christmas Day. The exact impacts will be very location-dependent as Far Northern Ontario including Sandy Lake through Lansdown House and into the Cochrane region will see heavy snowfall. For Northeastern Ontario, we’re looking at a mix of ice pellets/snow with the risk of prolonged freezing rain closer to Georgian Bay and Lake Superior around Sudbury and North Bay.

Precipitation will begin around the Manitoba border during the morning on Friday with persistent moderate to heavy snowfall expending eastward throughout the afternoon. By Friday evening, we expect the precipitation to start to move into areas east of Lake Superior where it will meet a layer of warmer air above the surface which will result in the development of a line of freezing rain and ice pellets. Current model guidance suggests that this line will stretch from Wawa through Chapleau and down into Sudbury. Keep in mind this is probably the most difficult part of the storm to forecast so it could be a little further north or south. Freezing rain will continue to linger around throughout the evening and even overnight into Christmas morning.

As we head into the later part of the morning on Saturday, we will see the bulk of the precipitation move out of the region. But light snow to the north and some freezing rain in the south will continue into the early afternoon. There is some concern regarding the potential ice accretion from the freezing rain because there won’t be a switch over to rain (except near the shorelines of Georgian Bay and Lake Superior). We also expect some colder air to flood in behind the system later in the day on Saturday which will help hold any of the ice in place on surfaces like trees and power lines. Don’t be surprised to see some power outages on Christmas Day that could continue for several days as the weight of the ice brings down more trees and power lines.

On the cold side of the storm, we’re looking at widespread accumulation ranging from 10-20cm for Far Northern Ontario. The bulk of the snowfall will come late Friday and into early Saturday morning. Lower amounts are expected further south where ice pellets will mix in and reduce the potential accumulation. Areas along the International border including Kenora and Thunder Bay will see mainly snow from this system, but accumulation is expected to be under 5cm due to lack of moisture so it’s not shown on the map.

Southern Ontario: Snowfall Outlook for Thursday, December 23, 2021

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Forecast Discussion

A fast-moving system is expected to bring a blast of snow to areas east of Lake Huron and into the GTA beginning Thursday late afternoon. It will continue throughout the evening hour with the snow tapering off just after midnight. In addition to this, the Sarnia and Chatham-Kent region could see some brief freezing rain just in time for the Thursday evening commute. Windsor should mainly see rain from this system. As for accumulation, this will be a fairly weak system in terms of moisture content so we expect around 2-6cm (locally as much as 10cm, but that seems unlikely) from the Lake Huron shoreline through K/W and into the GTA. Lower totals may be found along the shoreline of Lake Ontario as temperatures will be very close to the freezing mark. For those hoping for a White Christmas, we don’t expect the snow to stick around until Christmas with a warm-up on Christmas Eve and rain expected.

Northern Ontario: Snowfall Outlook for Friday, December 24, 2021

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Forecast Discussion

A system may affect parts of Northwestern Ontario late Friday with heavy snowfall or freezing rain. The precipitation will continue into Saturday making for a messy Christmas Day. A special forecast for this will be coming on Thursday.

Northern Ontario: Winter Weather Hazards Outlook for Friday, December 24, 2021

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Forecast Discussion

A system may affect parts of Northwestern Ontario late Friday with heavy snowfall or freezing rain. The precipitation will continue into Saturday making for a messy Christmas Day. A special forecast for this will be coming on Thursday.

White Christmas Almost Certain for Central and Eastern Ontario; Green Christmas Possible for GTA and Southwestern Ontario

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There was hope that the snowfall over the weekend across much of Southern Ontario might mean that a White Christmas was in the cards this year. However, it appears that Mother Nature will dash any hope of a White Christmas with a push of milder temperatures on Christmas Eve for Southwestern Ontario and the GTA/Niagara Region. There is good news that the cold air should hold on across Central and Eastern Ontario making a White Christmas almost certain this year for those regions.

In the lead-up to Christmas, we’re looking at the chance of some snow both on Wednesday with some lake effect snow around Lake Huron and Georgian Bay and a quick system late Thursday. The system on Thursday will likely deliver around 5cm of snow to parts of Southwestern Ontario and into the Golden Horseshoe. It’s quite possible that many locations even with a very low chance of a White Christmas will wake up to snow on the ground on Christmas Eve.

Don’t let that trick you though! Warmer air will slowly work its way into the province later on Friday (Christmas Eve) pushing the temperature above the freezing mark for areas around Lake Ontario, Erie and Huron along with Deep Southwestern Ontario. Some locations like Windsor may flirt with double-digit highs on Christmas Day! As a result, any snow that was on the ground on Christmas Eve morning will likely be gone by the time you go to bed. There is a chance that some of the higher elevations northwest of the GTA including Orangeville could still hold onto the accumulation long enough to still allow for a White Christmas, but it’s questionable at best. As we mentioned, the cold air will put up a fight across Central and Eastern Ontario so any existing snow accumulation should be maintained going into Christmas morning.

It should be noted that there is some uncertainty in this forecast as a potential system might affect Southern Ontario late on Christmas Eve. At this point, it appears that it could bring a mixed bag of precipitation depending on the track. Rain is looking likely for Southwestern Ontario and along the shoreline of Lake Ontario/Erie. Further north, we may see a freezing rain threat around Lake Simcoe and some accumulating snow through Central and Eastern Ontario.

Again, any shift in the track of this storm either to the north or south may significantly change the White Christmas probability. We might even see a ‘true’ White Christmas through Central and Eastern Ontario with snow coming down as you wake up Christmas morning. This is why a zone around Georgian Bay and extending through Lake Simcoe has only a 75% chance of a White Christmas as they could see some mixing from this system.

More details on this system will follow in the coming days including our final White Christmas forecast to be posted on Christmas Eve (Friday). Check back soon!

Northern Ontario: Snowfall Outlook for Tuesday, December 21 to Wednesday, December 22, 2021

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Forecast Discussion

Accumulating snowfall is expected across Northeastern Ontario late Tuesday continuing into Wednesday. Total accumulation from this system will generally range between 6-12cm with lower amounts further to the northwest. A few locations particularly east of Lake Superior and north of Georgian Bay could pick up as much as 15-20cm by the end of Wednesday due to some lake enhancement. There is also a zone including Timmins, Cochrane and Englehart that has shown up in multiple different weather models with the potential for accumulation reaching 15-20cm as well. The snow will come to an end by mid-day Wednesday.

Southern Ontario: Snowfall Outlook for Tuesday, December 21 to Wednesday, December 22, 2021

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Forecast Discussion

A weak system will move into northern parts of Southern Ontario late Tuesday evening bringing the potential for some light to moderate snowfall continuing into Wednesday. This will mainly affect Northeastern Ontario and into some parts of Central Ontario to the northeast of Georgian Bay. Total snowfall accumulation will generally range from 6-12cm, but a few locations along the northern shoreline of Georgian Bay could see up to 15-20cm due to lake enhancement helping to boost totals. The system will move out by Wednesday afternoon, however, lake effect snow is expected to develop off Lake Huron and Georgian Bay in the wake of the system.

Current indications suggest one main squall will set up off Lake Huron affecting the northern Grey and Bruce counties throughout the afternoon and into the evening. A few locations may approach 15-20cm by the end of Wednesday due to these squalls with more general amounts ranging from 5-10cm. For Georgian Bay, some heavier lake effect snow could result in accumulation between 6-12cm and locally up to 16cm in parts of Simcoe County.

The lake effect snow may linger into Thursday, but there is low confidence on intensity and location so that will be covered in a future forecast.