January 14, 2025

'Snow Day' Forecast: Questionable Chance for School Bus Cancellations on Wednesday in Parts of Southern Ontario

January 14, 2025/ Brennen Perry

***NOTE: YOU CAN CLICK ON THE MAP TO OPEN A ZOOMABLE IMAGE***

Snow squalls have persisted throughout Tuesday across regions near Lake Huron and Georgian Bay, delivering relentless snowfall. The Muskoka region, in particular, has been buried under more than 50 cm of snow between Monday night and Tuesday morning.

While the intensity of these squalls has diminished slightly, a shift in wind direction has caused them to drift southward into Simcoe, Huron, and Perth counties. Despite the weakening, the squalls are expected to linger overnight, continuing to impact travel and local conditions.

There remains some uncertainty regarding overnight snowfall amounts. Current projections indicate totals of 5-10 cm in most areas, with isolated pockets potentially seeing 10-20 cm.

However, Environment Canada has issued snow squall warnings for these regions, highlighting the potential for up to 30 cm of additional snow by Wednesday afternoon. If these higher totals materialize, they could prompt another round of school bus cancellations in the affected areas.

Meanwhile, the Muskoka region is still digging out from the massive snowfall earlier today. Although no additional accumulation is expected overnight, the sheer volume of snow already on the ground could lead to local school bus cancellations on Wednesday.

Here is a breakdown of the likelihood of school bus cancellations by region:

Possible (50–75% Chance)

Simcoe County District School Board (West Zone)
Avon Maitland District School Board (Goderich)
Bluewater (Kincardine)

Maybe (25–50% Chance)

Trillium Lakelands District School Board (South Muskoka)
Simcoe County District School Board (Central & South Zone)
Bluewater District School Board (Hanover & Southampton)
Avon Maitland (Listowel & Exeter)

Unlikely (10–25% Chance)

Near North District School Board (Town of Parry Sound)
Trillium Lakelands (North Muskoka)
Simcoe County District School Board (North Zone)
Bluewater (Owen Sound & Meaford)
STWDSTS (Dufferin)
Avon Maitland (Stratford)
Thames Valley (Middlesex)

For the rest of Southern Ontario, the chance of school bus cancellations on Wednesday is less than 10%.

Disclaimer: Instant Weather has zero authority when it comes to bus and school closures. It is completely up to the school boards, bus companies, local authorities, and parents to decide what is best for their children. This is our best guess based on our forecast.

January 13, 2025

'Snow Day' Forecast: Bus Cancellations Likely in Parts of Southern Ontario’s Snowbelt on Tuesday

January 13, 2025/ Brennen Perry

Intense snow squalls have developed off Lake Huron and Georgian Bay as of Monday afternoon and are forecasted to persist into Tuesday.

These squalls are expected to bring significant snowfall, with accumulations of up to 50 cm in some areas, particularly across Muskoka, Parry Sound, and the Grey-Bruce regions.

The worst conditions are likely overnight into Tuesday morning, characterized by near-zero visibility and hazardous travel conditions.

Given the severity of the forecast, it is highly likely that school boards in the hardest-hit areas of Central and Southwestern Ontario will cancel school bus services on Tuesday.

Environment Canada has issued a snow squall warning, highlighting that “rapidly accumulating snow could make travel difficult over some locations.”

Here is a breakdown of the likelihood of school bus cancellations by region:

Almost Certain (90% Chance)

Trillium Lakelands District School Board (South Muskoka)
Near North District School Board (Town of Parry Sound)
Bluewater District School Board (Bruce Peninsula & Southampton)

Likely (75–90% Chance)

Trillium Lakelands (North Muskoka)
Bluewater (Kincardine, Owen Sound & Meaford)

Possible (50–75% Chance)

Trillium Lakelands (Haliburton)
Near North (East Parry Sound)
Bluewater (Hanover)
Avon Maitland District School Board (Goderich)

Maybe (25–50% Chance)

Trillium Lakelands (North City of Kawartha Lakes)
Simcoe County District School Board (North Zone)
Avon Maitland (Listowel)

Unlikely (10–25% Chance)

Simcoe County District School Board (West Zone)
Avon Maitland (Exeter)

For the rest of Southern Ontario, the chance of school bus cancellations on Tuesday is less than 10%. These snow squalls are highly localized and will primarily impact the typical snowbelt regions around Lake Huron and Georgian Bay.

January 12, 2025

Intense Snow Squalls Return to Parts of Southern Ontario on Monday; Possible Deep Freeze for Late January

January 12, 2025/ Brennen Perry

⬇️ ZOOMED IN MAP CAN BE FOUND FURTHER DOWN ⬇️

The first half of January is almost behind us, and in Southern Ontario, the weather has shifted significantly compared to December. Colder temperatures have dominated, leading to several bouts of snow squall activity off Lake Huron and Georgian Bay. These events have primarily impacted regions southeast of the lakes.

The threat of snow squalls is set to return this week, with the heaviest snow expected east of Lake Huron and Georgian Bay. A predominant westerly flow will target areas such as Parry Sound, Bracebridge, Gravenhurst, and parts of Grey and Bruce counties. This pattern is reminiscent of what we experienced in early December, with heavy snow focused in the snowbelt regions east of Georgian Bay.

Snow squalls are forecasted to develop Monday afternoon and further intensify into the evening and overnight hours. Rapid snowfall accumulation and near-zero visibility are likely, especially late Monday into early Tuesday.

By the time the squall activity tapers off on Tuesday afternoon, some localized areas in the Muskoka and Parry Sound regions could see totals between 25 and 50 cm.

A brief reprieve from lake-effect snow is expected after Tuesday as milder air moves into Southern Ontario. However, another Arctic plunge is anticipated by early next week, potentially bringing some of the coldest air of the season.

Wind chills could make it feel like -30°C or even -40°C, especially in Central and Eastern Ontario!

This upcoming cold snap could also reignite intense lake-effect snow activity, with several rounds of squalls likely to impact the snowbelt regions throughout the rest of January.

BREAKING DOWN THE TIMING OF THE SQUALLS

Before the snow squalls begin Monday, a weak clipper system is forecasted to move across Southern Ontario late Sunday into early Monday morning. While this system will lack significant moisture, it may bring light snowfall of 2 to 5 cm in most areas, with localized pockets potentially reaching up to 5 cm.

**HOURLY SNOWFALL RATE/intensity** - MAP FROM WEATHERBELL

In the wake of the clipper, lake-effect snow is expected to ramp up east of Georgian Bay on Monday afternoon. Initially, the snow may be disorganized, spreading moderate to heavy snowfall across Muskoka and parts of Grey and Bruce counties.

By Monday evening, forecast models indicate the formation of a more organized snow squall. This band is expected to stretch from the Bruce Peninsula across Georgian Bay and inland between MacTier and Parry Sound.

The squall could remain stationary overnight, leading to rapid snowfall accumulation at rates of 5 to 10 cm per hour.

Model projections differ slightly regarding the exact placement of the most intense squall. The American model places the heaviest snow over Parry Sound, Pointe au Baril, Sprucedale, and Burk’s Falls.

Meanwhile, the Canadian model suggests the squall may shift south after midnight, targeting areas such as Port Carling, Rosseau, Port Sydney, and Bracebridge for the heaviest snowfall.

Both models agree that the squall will gradually sink southward by late Tuesday morning, bringing heavy snow to northern Simcoe County, including Midland and Orillia.

However, there is uncertainty about the intensity and duration of the squall as it moves further south into Barrie.

While Georgian Bay will see the most intense squalls, Lake Huron is also expected to generate less intense snow bands Monday evening into Tuesday morning. These bands could impact Owen Sound, Kincardine, and Hanover, with bursts of heavy snow.

As the wind shifts southward, areas like Goderich and London may briefly experience lake-effect snow Tuesday morning into the afternoon.

WHO COULD GET BURIED IN SNOW

As is typical with lake-effect snow, snowfall totals will vary widely depending on where the narrow bands persist. The highest accumulations are expected in Parry Sound, Rosseau, Port Carling, Port Sydney, Bracebridge, and Gravenhurst, where 25 to 50 cm of snow is possible by Tuesday afternoon.

In some areas, totals could exceed 50 cm if the squall remains stationary for an extended period.

Surrounding areas such as Midland, Washago, Coboconk, Minden, Huntsville, and Sprucedale may see snowfall totals of 15 to 25 cm.

The Grey-Bruce region, including Kincardine, Port Elgin, Wiarton, Lion’s Head, Tobermory, Owen Sound, Chatsworth, Hanover, and Meaford, is expected to receive 15 to 25 cm, with localized totals of 30 to 40 cm if squalls intensify.

Elsewhere in Central and Southwestern Ontario, snowfall amounts will range from 5 to 15 cm, combining accumulation from the weak clipper system and lake-effect snow. Most areas will see closer to 5 cm, with lake-effect zones reaching 10 to 15 cm.

Less than 5 cm is expected for the rest of Southern Ontario.

SNOW SQUALL WATCH ISSUED BY ENVIRONMENT CANADA

CURRENT ENVIRONMENT CANADA ALERTS AS OF SUNDAY EVENING

Environment Canada has issued snow squall watches for areas around Lake Huron, Georgian Bay, and Lake Superior.

The highest totals in these watches match our forecast, with 20 to 40 cm expected for Parry Sound and Muskoka and 15 to 25 cm for the Grey-Bruce region.

Northern Ontario, including Sault Ste. Marie and Manitoulin Island could see localized snowfall of 10 to 20 cm from Monday evening into Tuesday morning.

LOOKING AHEAD TO THE REST OF JANUARY

The persistence of lake-effect snow this far into January may seem unusual, but the Great Lakes remain relatively ice-free and warmer than usual due to a mild fall and warm start to winter. This provides ample moisture for snow squalls when Arctic air moves in.

**ICE COVERAGE MAP AS OF JANUARY 11, 2025** - source: NOAA

Colder weather in recent weeks has helped cool the lakes and increased ice coverage, particularly in shallower areas like Lake Erie and the shorelines of Lake Huron and Georgian Bay.

Ice coverage has risen from 1% at the start of January to over 10% as of January 11.

**TEMPERATURE ANOMALY** - MAP FROM WEATHERBELL

Looking ahead, a significant Arctic blast is expected during the January 20–24 period, with temperatures 10 to 20 degrees below seasonal norms across much of Southern Canada and the northern U.S.

Southern Ontario could experience lows well below -20°C, potentially nearing -30°C in some areas. Wind chills could make it feel as cold as -35°C to -40°C, particularly in Central and Eastern Ontario.

This intense cold will likely bring additional snow squalls and accelerate ice formation on the Great Lakes. If current trends continue, lake-effect snow activity could diminish significantly by the end of the month as ice coverage increases, shutting off the moisture source for squalls.

For snowbelt residents weary of lake-effect snow, relief may finally be on the horizon!

January 10, 2025

Looking Back on Canada's Costliest Winter Disaster: The Ice Storm of January 1998

January 10, 2025/ Alannah Campbell

*A downed hydro pylon in Quebec following the ice storm in January 1998, courtesy of* *CBC News*.

As Canadians rang in the New Year in January 1998, millions were unaware that in only a few days, they’d be caught in the middle of the costliest natural disaster in Canadian history. This is a record that stood for over 18 years, until the Fort McMurray fire of 2016. Nevertheless, it remains the most expensive winter disaster Canada has ever seen.

A 40,000km² area that covered Eastern Ontario and Upstate New York, up the St Lawrence Valley through Montreal, into the Eastern Townships of Quebec and across Maine into New Brunswick was coated in up to 100mm of ice that fell as freezing rain from the 5th until the 10th of January 1998. Light freezing rain was even experienced in Waterloo Region, to the west of Toronto and extended as far east as Western Nova Scotia. It’s important to note that this wasn’t a single storm, but rather a series of three smaller storms that produced freezing rain and ice pellets over an almost week-long period.

The Christmas Break in December 1997 was cold and snowy across much of Southern Ontario and Quebec so it was refreshing when New Year’s Day brought mild temperatures and sunshine to the region. However, a concerning weather pattern was shaping up.

*The surface chart from January 7th, 1998 showing the positions of the high and low pressure, areas of precipitations (shaded in darker grey) and the temperatures in degrees Fahrenheit, courtesy of* *the National Weather Service*.

In the coming days, a strong high pressure area settled over Northern Quebec, which forced cold Arctic air southwards, while multiple low pressure systems from the south funnelled warm, moist air northwards. When the two air masses collided, the warm air rose above the cold air and then when the rain fell from the warm air mass, it froze on contact with surfaces at ground-level where the air was much colder.

This is what typically occurs in freezing rain events, but what made this different was the persistent flow of warm, moist air straight from the Gulf of Mexico continuing over several days, turning this into a prolonged event.

Temperature Profiles and the formation of different precipitation types.

The moist Gulf air arrived first, on January 4th, and brought mild temperatures and light rain to most of the impacted region. The next day, the Arctic air moved in and settled below the warmer air mass, bringing surface temperatures back below freezing and resulting in the transition from rain to freezing rain.

The high pressure continued to build over Northern Quebec throughout the following days, which maintained the flow of Arctic air, while the moist Gulf air surged northward in three distinct rounds of precipitation. According to Environment Canada, these three waves were: from 6:00pm on January 5th to 8:00am on January 6th, from 6:00pm on January 7th to 8:00am on January 8th, and from the morning of January 8th until the morning of January 9th.

Overall, an average of 50-70mm of freezing rain fell across the entire region. However, an area later called the “Triangle of Darkness”, between the towns of Saint-Hyacinthe, Granby, and Saint-Jean-sur-Richelieu, was hit the hardest, with more than 100mm of ice accretion.

*Total Ice Accretion amounts from the January 1998 Ice Storm, courtesy of* *the National Weather Service*.

*Map of the total Ice Accretion from the January 1998 Ice Storm, with a Focus on Eastern Ontario and Southern Quebec, Courtesy of* *Hydro Quebec*.

It didn’t take long for the effects of the ice buildup to be felt. Transportation quickly came to a halt as roads and sidewalks became skating rinks and vehicles were completely encased in ice.

After 10-20mm of freezing rain from the first round of precipitation, tree branches were already bending under the weight of the ice and as more freezing rain fell, the branches broke and entire trees toppled. Residents reported that the continuous sounds of ice-covered trees and branches breaking and falling was akin to gunshots. No definitive number was ever established, but it is estimated that millions of trees fell as a result of this storm.

It was also early on in the event that the strain on the power grid was felt and it only got worse as the freezing rain continued. Transmission lines sagged with the extra weight and short circuits caused by ground wires sagging and touching live wires tripped switches. Fasteners responsible for holding these lines were unable to handle the extra weight from all of the ice and snapped, while entire hydro poles and large towers eventually collapsed.

On top of all of this, transformers were damaged and caught fire, leading to further destruction of the hydro distribution system. Overall, 1,000 hydro pylons crumpled and at least 30,000 hydro poles were destroyed, plunging over 4 million people in Ontario, Quebec, and New Brunswick into darkness.

*A montreal street covered in ice from the January 1998 ice storm, courtesy of* *Hydro Quebec*.

While most people who were impacted by the ice storm were in urban areas, two groups in particular were significantly impacted in rural regions.

The stretch of the country hit by the ice storm was home to roughly 25% of all dairy cows in Canada and farmers encountered considerable challenges with the loss of power. Many cows got sick when it became difficult to feed them, milk them, and keep them warm.

With the lack of power at processing plants, over 10 million litres of milk, worth roughly $5 million, had to be dumped. Hydro Quebec reports that it was able to provide generators to many cattle farmers in the province, but unfortunately an estimated 300,000 farm animals across the entire region died in the cold.

Quebec’s maple syrup industry also took a massive hit with the ice storm. More than 20% of syrup-producing trees were damaged or destroyed as branches fell or large pieces of the trees splintered off, and equipment collapsed under the weight of the ice. Some syrup producers had their entire sugar bushes destroyed and while trees and the industry have mostly recovered, some scars still remain.

*A convoy of troops deployed from Petawawa en Route to aid victims of the ice storm, taken January 9th, 1998, Courtesy of* *Veterans Affairs Canada*.

On January 7th, at the peak of the ice storm, the Provincial Governments of Ontario, Quebec, and New Brunswick appealed to the Federal Government for assistance. The next day, 15,000 members of the Canadian Armed Forces were deployed from 200 different units from across the country as part of Operation Recuperation, making this this largest peacetime deployment of troops in Canadian history.

Troops worked with hydro companies to help restore power, cleared tree limbs and other debris, evacuated residents, and provided shelter, food and medical care to victims. The Operation eventually concluded on February 28th, 1998.

Due to the sheer level of damage across such a large area, the cleanup of debris and restoration of power was not something that was going to occur overnight. Temperatures plummeted following the ice storm to -20°C, so staying warm was the number one concern in the aftermath.

Many people were able to stay with family and friends who still had power, but emergency shelters were set up and available for those with nowhere else to go. Approximately 600,000 people were temporarily displaced from their homes while crews worked to restore power.

Thankfully, hydro crews from across the country and the United States came to the aid of those in the disaster area. The power was restored to many people in urban areas after a few days, but efforts took longer in rural communities, with roughly 700,000 people still without power three weeks after the storm.

The ice storm was a real testament to the sense of community as well as the welcoming and giving nature of Canadians. Many people came together to help clean up and provide food and shelter to those in need. Despite all this, the storm resulted in 945 injuries and 35 people sadly lost their lives.

On top of the human cost, the storm had a very large financial cost. The incredible amount of damage caused by this storm was estimated to have cost insurers $1.38 billion. Furthermore, entire cities were shut down and 2.6 million people in Ontario and Quebec, consisting of close to a fifth of the Canadian workforce, unable to get to work. The loss of productivity was over $1 billion and when added to insured damages and the over $2 billion it cost to repair utilities, the overall financial cost of the storm is estimated at $5.4 billion.

Further Reading:

https://canadiangeographic.ca/articles/lessons-learned-from-the-ice-storm-of-1998/

https://www.cbc.ca/news/canada/montreal/ice-storm-1998-1.4469977

https://www.hydroquebec.com/ice-storm-1998/

https://www.thecanadianencyclopedia.ca/en/article/ice-storm-1998

https://www.veterans.gc.ca/en/remembrance/wars-and-conflicts/caf-operations/service-in-canada/ice-storm

https://www.weather.gov/btv/25th-Anniversary-of-the-Devastating-1998-Ice-Storm-in-the-Northeast

January 09, 2025

Widespread Snowfall to End the Week Across Southern Ontario on Friday; Up to 5-10cm Possible

January 09, 2025/ Brennen Perry

While 2025 began with heavy snow across parts of Southern Ontario, most of the activity so far has been confined to traditional snowbelt regions. That’s about to change, as a new system is set to bring the first widespread snowfall of the year to much of Southern Ontario starting Friday.

Most of Southwestern, Central, and Eastern Ontario can expect snowfall totals of 5 to 10 cm between Friday afternoon and Saturday morning. However, areas along the Lake Huron shoreline and into the Bruce Peninsula may see enhanced snowfall, with totals reaching 10 to 20 cm due to lake-effect activity and embedded snow squalls.

As the system moves out, additional snowfall is likely over the weekend. Lake-effect snow squalls developing southeast of Lake Huron and Georgian Bay could bring localized accumulations of 20 to 30 cm from Saturday afternoon into Sunday.

SNOWFALL TIMING

**PRECIPITATION TYPE** - MAP FROM WEATHERBELL

The system-related snowfall will begin spreading into Southwestern Ontario late Friday afternoon, with regions near Lake Huron, including Deep Southwestern Ontario, seeing snow first.

Through the dinner hours, the snow will advance northeast, gradually reaching the Golden Horseshoe and portions of Central Ontario by Friday evening. By midnight, snow will cover most of Southern Ontario, extending into Eastern Ontario.

The most intense period of snowfall is expected overnight Friday into early Saturday morning. While the snow will generally be light, it could lead to several hours of steady accumulation, potentially impacting travel.

Exercise caution if you plan to drive during this time, and remember to adjust your speed to match road conditions.

For areas along the Lake Huron shoreline and into the Bruce Peninsula, lake-enhanced snowfall could intensify during the evening and overnight hours on Friday, resulting in heavier accumulations compared to surrounding areas.

Snowfall from this system will taper off from west to east starting early Saturday morning in Southwestern Ontario, with Eastern Ontario holding onto snow until late morning.

Flurries may linger into Saturday afternoon, especially in some regions.

As the system exits, lake-effect snow squalls may develop off Lake Huron and Georgian Bay by Saturday afternoon. Forecast models currently show some uncertainty about how organized these squalls will be and whether they will lock into specific areas for prolonged periods.

Higher-resolution models are just coming into range, so a detailed forecast for snow squall activity will be issued on Friday.

HOW MUCH SNOW TO EXPECT

In terms of totals, most of Southern Ontario will see 4 to 8 cm of snowfall, with slightly higher amounts of up to 10 cm possible in localized areas. This includes the east end of the Greater Toronto Area (GTA), such as Oshawa, and parts of Southwestern Ontario due to minor lake enhancement from Lake Ontario and Lake Huron.

The Golden Horseshoe and Ottawa Valley are expected to see slightly lower snowfall amounts, closer to 3 to 6 cm.

A zone along the Lake Huron shoreline—including Grand Bend, Goderich, Kincardine, and the Bruce Peninsula—could see locally higher accumulations by Sunday afternoon. Current estimates suggest 10 to 15 cm for these areas, with up to 20 cm possible for the Bruce Peninsula.

WEEKEND SNOW SQUALL PREVIEW

Environment Canada has identified areas near Barrie, Goderich, and London as hotspots for the most intense snow squalls over the weekend.

Here’s Environment Canada’s weekend outlook:

Saturday, January 11, 2025: “Lake effect snow squalls off Lake Huron and Georgian Bay are expected to develop Saturday afternoon. Local snowfall amounts of 10 to 15 cm are possible along with reduced visibility in heavy snow.”
Sunday, January 12, 2025: “Lake effect snow squalls off Lake Huron and Georgian Bay are expected to continue on Sunday. Local snowfall amounts of 10 to 15 cm are possible along with reduced visibility in heavy snow.”

As always, stay tuned for updates, especially if you’re in areas likely to experience lake-effect snow. Stay safe, and plan ahead for winter driving conditions!

January 07, 2025

'Snow Day' Forecast: Snow Squalls May Cancel School Buses in Parts of Central and Southwestern Ontario on Wednesday

January 07, 2025/ Brennen Perry

Snow squalls have formed along the southeastern shoreline of Lake Huron and the southern shoreline of Georgian Bay, creating challenging conditions across these regions. These squalls are expected to persist throughout Wednesday, bringing significant snowfall accumulation and reducing visibility, making travel potentially hazardous.

Given the ongoing conditions, there is a strong likelihood of school bus cancellations in areas most heavily impacted by the snow squalls. The highest chances are in Middlesex County, southern Huron County, Meaford, and the "West" zone of Simcoe County, where we estimate a 75% likelihood of cancellations.

For regions including the rest of Huron County, southern Perth County, and the City of London, the chance of school bus cancellations drops to around 50%. Meanwhile, areas such as Dufferin County and the "Central" and "South" zones of Simcoe County have a lower likelihood, with an estimated 25% chance of cancellations.

Outside of these areas, the rest of southern Ontario is unlikely to experience significant disruptions. The lake effect snow will remain highly localized, sparing most of the region from any substantial impact.

January 07, 2025

Mid-Week Squalls Could Dump Up to 25-50cm of Snow to Parts of Southwestern Ontario by Thursday

January 07, 2025/ Brennen Perry

The New Year has certainly started on a frigid note across Ontario, as Arctic air has firmly settled over the region in recent days. These cold temperatures, combined with open lakes, have created the perfect conditions for lake-effect snow. Late last week and into the weekend, parts of the province experienced significant snowfall, with totals southeast of Georgian Bay reaching or exceeding 50 cm.

Over the past 24 hours, the lake-effect machine has largely taken a break, aside from some minor activity south of Lake Huron and Georgian Bay. However, that respite will be short-lived. Beginning Tuesday evening, snow squalls are expected to return with a vengeance as wind directions realign and even colder air moves into the region. These squalls are anticipated to persist through Wednesday and into early Thursday before tapering off.

This round of lake-effect snow will likely target areas that were largely spared during the last event. The focus this time will be on regions southeast of Lake Huron and along the southern shoreline of Georgian Bay. Some of the hardest-hit areas could include London and Collingwood, with snowfall totals potentially ranging from 25 to 50 cm over the next 48 hours.

As for the timing, models differ slightly on the intensity and precise placement of the squalls. The latest data suggests snow squalls could begin organizing as early as Tuesday evening. The squall off Georgian Bay is expected to impact the Collingwood and Blue Mountain area, stretching inland toward Creemore, Alliston, and Shelburne. It may also affect the Highway 400 corridor just south of Barrie.

Meanwhile, activity off Lake Huron could produce multiple squalls developing between Kincardine and Grand Bend, with bands extending inland in a southeasterly direction. This puts portions of Huron, Perth, and Middlesex counties in the crosshairs.

The Georgian Bay squall appears to be somewhat weaker than its Lake Huron counterpart, likely due to the smaller lake surface area supplying moisture. That said, it is expected to remain relatively stationary through the overnight hours into Wednesday, resulting in steady snowfall accumulation and reduced visibility.

Travel in this area will likely be challenging from Tuesday night into Wednesday, with little improvement expected until the activity begins to subside overnight.

Lake Huron squalls, on the other hand, are expected to shift around more frequently, spreading out snowfall accumulations. By Wednesday morning, the primary squall is forecasted to come ashore around Grand Bend, extending inland toward Lucan, Strathroy, and London.

There is still some uncertainty about whether the squall will directly impact the City of London or remain just northwest. Western parts of the city are likely to see the heaviest snowfall, while eastern areas may receive lighter accumulations.

Scattered snow squalls east of Lake Huron are expected to continue affecting Huron and Perth counties throughout Wednesday. These squalls may vary in intensity, and if one becomes particularly organized and stalls over an area, rapid snowfall accumulation could occur.

The most intense conditions are expected during the day on Wednesday, extending into the evening and overnight hours.

By midnight, the lake-effect activity is expected to become more localized. The Georgian Bay squall will likely retreat closer to the shoreline, while the Lake Huron squalls may consolidate into a narrower band near Grand Bend, extending into the London area.

While this will reduce the overall impact, areas caught under these more focused squalls could experience increased snowfall rates for several hours overnight into early Thursday morning.

By pre-dawn Thursday, the lake-effect activity is anticipated to taper off, with the Georgian Bay squall dissipating before sunrise and the Lake Huron squall following a few hours later.

Snowfall totals from this round of snow squalls will vary widely, as is typical with these events. This forecast is particularly tricky due to discrepancies in model data regarding the intensity of the snow bands, which will significantly affect accumulation.

Based on the current environment and dynamics, there is potential for 25 to 50 cm of snow in areas such as London, Lucan, Grand Bend, Clinton, and Collingwood. However, these totals are not guaranteed, as exact amounts will depend on where the bands set up.

For London, in particular, snowfall accumulations will likely be heavier in the northwest, while eastern areas may only see totals between 10 and 25 cm.

Surrounding areas like Goderich, Point Clark, Mitchell, Strathroy, and St. Thomas could see localized accumulations of 15 to 25 cm, depending on the positioning of the bands. Similarly, areas southwest of Barrie, including Angus, Alliston, and Beeton, may receive 10 to 20 cm as the Georgian Bay squall extends inland.

Outside these regions, significant snowfall is not expected due to the highly localized nature of lake-effect activity. However, portions of Eastern Ontario near the U.S. border and areas east of Ottawa may see 5 to 10 cm of accumulation on Wednesday due to a separate system lingering over Quebec.

January 03, 2025

Snow Squall Blast Continues This Weekend as Parts of Southern Ontario Could See an Additional 25-50cm of Snow

January 03, 2025/ Brennen Perry

The New Year has certainly started on a snowy note for parts of Ontario's snowbelt regions. A multi-day snow squall event is underway around Lake Huron and Georgian Bay, with some areas already receiving over 50 cm of snow. Locations east of Lake Huron, Simcoe County, and parts of Kawartha Lakes have been among the hardest hit so far.

While the activity off Georgian Bay weakened somewhat on Friday evening, it's expected to ramp up again by Saturday afternoon and continue through Sunday. Snow squalls will also persist east of Lake Huron Friday night into Sunday, though the bands will shift around multiple times during this period.

By the end of the weekend, some areas could see an additional 25 to 50 cm of snow, with localized totals reaching as high as 75 cm. Combined with the snow that has already fallen, totals in the hardest-hit regions could exceed one meter (100 cm). This includes parts of Simcoe County, where 50 to 75 cm of snow has already accumulated over the past two days.

As of Friday evening, multiple discrete squalls off Lake Huron are bringing heavy snow to areas stretching from Bayfield to Kincardine and as far inland as Woodstock, Kitchener, and Guelph. This activity is expected to continue through the night, with southern squalls gradually merging northward by early Saturday morning.

The New Year has certainly started on a snowy note for parts of Ontario's snowbelt regions. A multi-day snow squall event is underway around Lake Huron and Georgian Bay, with some areas already receiving over 50 cm of snow. Locations east of Lake Huron, Simcoe County, and parts of Kawartha Lakes have been among the hardest hit so far.

While the activity off Georgian Bay weakened somewhat on Friday evening, it's expected to ramp up again by Saturday afternoon and continue through Sunday. Snow squalls will also persist east of Lake Huron Friday night into Sunday, though the bands will shift around multiple times during this period.

By the end of the weekend, some areas could see an additional 25 to 50 cm of snow, with localized totals reaching as high as 75 cm. Combined with the snow that has already fallen, totals in the hardest-hit regions could exceed one meter (100 cm). This includes parts of Simcoe County, where 50 to 75 cm of snow has already accumulated over the past two days.

As of Friday evening, multiple discrete squalls off Lake Huron are bringing heavy snow to areas stretching from Bayfield to Kincardine and as far inland as Woodstock, Kitchener, and Guelph. This activity is expected to continue through the night, with southern squalls gradually merging northward by early Saturday morning.

By Saturday morning, an intense squall is expected to form between Sauble Beach and Kincardine, extending inland to areas such as Hanover, Dundalk, and Orangeville. This band may stretch as far east as the western GTA, including Mississauga and Brampton.

While overall accumulations in the GTA should remain around 5 cm or less, these squalls could still lead to near-zero visibility and hazardous travel conditions due to blowing snow.

For Georgian Bay, lingering lake-effect activity will continue Friday night into Saturday morning, though no significant squalls are expected until later in the day.

By mid to late Saturday afternoon, the Lake Huron squall is expected to shift northward as wind directions change. This will allow it to cross over the southern Bruce Peninsula and connect with Georgian Bay, bringing heavy snowfall to Simcoe County, particularly in the Barrie-Orillia corridor.

This squall may also extend into parts of northern York and Durham regions, as well as the Kawartha Lakes region.

As seen earlier in this event, the squall is expected to lock in place, leading to intense snowfall rates of 5 to 10 cm per hour late Saturday through Sunday. Driving conditions will deteriorate rapidly, and non-essential travel should be avoided due to the potential for road and highway closures.

By late Sunday morning, the Georgian Bay squall is expected to sink southward, bringing an end to the snow for areas southeast of the bay. Moderate to heavy lake-effect snow may persist in parts of Grey and Bruce counties throughout Sunday, with activity finally tapering off overnight into Monday morning.

The heaviest snowfall totals are expected in areas such as Wiarton, Owen Sound, Kincardine, Hanover, Meaford, Collingwood, Wasaga Beach, Midland, Barrie, Orillia, and Beaverton. These regions could see an additional 25 to 50 cm of snow by the end of the weekend, depending on the squall locations.

Surrounding areas, including Goderich, Woodstock, Stratford, Kitchener, Guelph, Angus, Bradford, Lindsay, and Port Perry, may also see significant snowfall if the squalls align. These areas could receive 15 to 25 cm of snow, though amounts will vary widely due to the localized nature of snow squalls. Our forecast is intentionally broad to account for potential shifts in squall placement.

Snowfall amounts will drop off quickly outside the snowbelt regions. However, parts of the northern and western GTA could see 5 to 10 cm, with isolated amounts up to 15 cm. Even Toronto might get a few centimeters of brief, heavy snow as the bands shift inland.

Eastern and Deep Southwestern Ontario are not expected to see any significant snowfall from this event.

January 01, 2025

Snowy Start to 2025 in Ontario’s Snowbelt; Squalls Could Deliver Up to 50cm of Snow by End of Week

January 01, 2025/ Brennen Perry

As we kick off the New Year across Ontario, we’re starting off with a blast of cold Arctic air that moved into the region over the past 24 hours. With this chilly air comes the inevitable return of lake-effect snow in the traditional snowbelt areas surrounding Lake Huron, Georgian Bay, and Lake Superior.

Strong snow squalls are anticipated to develop Wednesday evening and are likely to persist through Thursday and into Friday. These squalls are expected to bring intense snowfall rates of 5-10 cm per hour, along with near-zero visibility that will make travel nearly impossible in the hardest-hit areas.

The main focus for this lake effect activity will be in parts of Huron, Perth, Grey, Bruce, and Simcoe counties. Depending on where these narrow snow bands establish, localized accumulations could approach or exceed 50 cm by week’s end, with additional snowfall possible through the weekend as the lake effect machine remains active.

Disorganized squalls are expected to begin forming off Lake Huron and Georgian Bay late Wednesday evening or around midnight. According to the latest data, multiple bands could develop off Lake Huron, with one possibly targeting areas south of Owen Sound.

Another band may stretch from Goderich inland towards Stratford and St. Marys, just north of London. However, there remains some uncertainty about where exactly these squalls will set up, which will determine the heaviest snowfall locations.

For Georgian Bay, models show differing timelines. One suggests squall activity could begin just after midnight, while another predicts development near sunrise on Thursday. If squalls form, areas like Wasaga Beach and Barrie could be affected overnight.

Overnight, the bands that do form may shift around and dissipate periodically, spreading snowfall over a broader area. If a squall locks into place unexpectedly, snowfall can accumulate rapidly in a short time.

The event is expected to intensify by mid to late Thursday morning as the northern squall off Lake Huron drifts northward, potentially crossing the Bruce Peninsula and reconnecting over Georgian Bay. This setup could lead to a rare "multi-lake connection," allowing the squall to draw moisture from a long stretch of open water.

The result would be heavy snowfall affecting areas such as Owen Sound, Collingwood, Wasaga Beach, and Barrie, with possible extensions into Durham Region and southern Kawartha Lakes.

Another squall off Lake Huron could extend inland into Huron and Perth counties, with potential impacts as far as Kitchener-Waterloo. While intense snowfall could occur, squalls are notoriously narrow, and not all areas will be directly affected.

By late Thursday afternoon, snow squalls off Lake Huron may weaken as the wind shifts more westerly, reducing the available lake surface from which the squalls can pull moisture. The Georgian Bay squall, however, could continue intensifying and shift northward, potentially impacting areas like Midland and Orillia while giving Barrie a break.

There remains uncertainty regarding the squall's position, with some models suggesting it may remain south of Orillia. If the squall locks in place overnight, areas such as Simcoe County and southern Kawartha Lakes could see prolonged periods of heavy snow, leading to extremely poor travel conditions, potential road closures, and significant snowfall accumulations.

By late Friday morning, shifting winds are expected to push the Georgian Bay squall southward, potentially dissipating it by midday. However, lake effect activity off Lake Huron may persist southeast of the lake into areas like Kitchener and London through Friday afternoon and evening.

The hardest-hit regions from this event will likely include Grey-Bruce and southern and central Simcoe County, including Wasaga Beach and Barrie. Snowfall totals in these areas could range from 25 to 50 cm by Friday night.

Some localized spots, particularly between Barrie and Orillia, may see totals exceeding 50 cm, with the potential for as much as 75 to 100 cm. However, model disagreement prevents us from confidently forecasting such extreme totals.

It’s important to note that snow squalls are highly localized phenomena, often only a few kilometres wide. While our forecasts aim to highlight the most likely zones, the reality is that squalls can shift unexpectedly, meaning not every location in a forecasted zone will see the same impacts.

Surrounding areas, including Orillia, Lindsay, Fenelon Falls, and Port Perry, could see localized snowfall of 15-25 cm from the Georgian Bay squall, with totals tapering quickly outside of this zone. Peterborough and areas along the Lake Ontario shoreline between Oshawa and Brighton may see 5-15 cm.

For regions east of Lake Huron, a narrow band from Goderich to Wingham and Listowel could see 25-50 cm of snow, with some extension into Kitchener, where totals may approach 15-20 cm. However, the exact setup will depend on the squall’s inland reach.

Elsewhere, the Golden Horseshoe could see a few centimeters of snow from brief, heavy bursts of lake effect activity, but no significant accumulations are expected. Areas north of Bracebridge, east of Peterborough, and south of Woodstock are likely to see little to no snow.

As always, lake effect snow forecasts carry inherent uncertainty. While many areas may receive less snow than forecasted, those directly in the path of these intense squalls could see the full brunt of the snowfall. Be prepared for rapidly changing conditions, and avoid non-essential travel in the hardest-hit zones.

Snow squalls are also expected to affect regions east and southeast of Lake Superior in Northern Ontario starting Wednesday evening. These squalls will continue to persist throughout the day on Thursday before shifting south of the border.

The Sault Ste. Marie region appears to be in the bullseye and could see localized snowfall totals between 25 to 50cm by the time the snow tapers off late Thursday.

December 31, 2024

Heavy Snow Could Impact New Year’s Eve Celebrations in Southern Ontario With Up to 10-20cm of Snow

December 31, 2024/ Brennen Perry

After a brief return to milder weather accompanied by heavy rain to cap off the final weekend of the year, a snowy blast is on the horizon to kick off the first few days of 2025.

A system is expected to move into Southern Ontario starting Tuesday afternoon, bringing a mix of precipitation that will gradually transition to snow as we ring in the New Year at midnight. For those heading out to celebrate New Year’s Eve, road conditions may become hazardous, particularly later in the evening as temperatures drop below freezing.

Snowfall is expected to continue throughout New Year’s Day on Wednesday, with the heaviest accumulation focused on parts of Central and Eastern Ontario. By the time the snow tapers off late Wednesday, some areas could see snowfall totals nearing 10 to 20 cm in the hardest-hit regions.

In the wake of this system, frigid Arctic air is set to return, dominating the weather pattern for at least the first week of 2025. With the Great Lakes still largely unfrozen, the lake-effect snow machine is expected to roar back to life, potentially resulting in a multi-day snow squall event.

Starting Thursday and continuing into the weekend, some areas in the traditional snowbelt regions near Lake Huron and Georgian Bay could see significant snowfall, with totals approaching 50 cm by the end of the weekend.

The New Year’s Eve system is forecast to bring the first scattered bands of precipitation into the region from the south and west during the early to mid-afternoon hours on Tuesday. Areas in Deep Southwestern Ontario and near the Lake Erie shoreline will be affected first, with the precipitation gradually spreading across Southern Ontario by the dinner hour.

At this time, most regions are expected to hover near or just above the freezing mark, particularly in the Golden Horseshoe, where temperatures are likely to range between 3 and 5°C. As a result, the precipitation will likely begin as scattered rain or drizzle in many areas.

However, higher elevations northwest of the Greater Toronto Area (GTA) and into Central Ontario may see a mix of rain, ice pellets, and wet snow as temperatures there will be closer to freezing.

By the evening, the heaviest precipitation is expected to be concentrated east of Lake Huron, extending into Central Ontario. This will increasingly fall as wet snow as temperatures cool. Meanwhile, regions near the shores of Lake Ontario and Lake Erie will see less sustained precipitation, with rain continuing to dominate, especially near the lakeshore.

As the clock strikes midnight to welcome the New Year, heavy snow will continue in Central & Southwestern Ontario, while moderate to heavy rain will likely persist along the Lake Ontario and Lake Erie shorelines, dampening New Year’s Eve celebrations in the GTA and Niagara region.

Overnight, the precipitation is expected to transition to heavy, wet snow across most areas as colder air moves in behind the system. However, areas close to the Lake Ontario shoreline, including Hamilton, Toronto, and Kingston, may continue to experience rain into the early hours of Wednesday. Wet snow may mix in later in the morning, but periodic rain is likely as temperatures hover near freezing throughout Wednesday afternoon.

Moderate to heavy snow is forecast to persist through Wednesday in Eastern and Central Ontario, tapering off in Southwestern Ontario by the evening. In Eastern Ontario, steady snow could continue past midnight, finally ending early Thursday morning. Some lake-effect snow may develop off Lake Huron and Georgian Bay as early as Thursday morning.

Snowfall totals are challenging to predict for this system due to temperatures hovering close to freezing, which could significantly impact snow accumulation. A slight shift in temperatures could cause the system to overperform or underperform expectations.

The highest snowfall totals are expected in higher elevations of Central and Eastern Ontario, including Sundridge, Huntsville, Algonquin Park, North Bay, Deep River, and Bancroft. These areas could see between 10 and 20 cm of fresh snow by Thursday morning.

A wide swath of Southern Ontario, including much of Eastern Ontario, the Lake Simcoe region, and parts of Southwestern Ontario, is forecast to receive between 5 and 10 cm of snow. Localized areas may exceed 10 cm and approach 15 cm.

Around 2 to 5 cm of snow is expected for Ottawa, Brockville, Kingston, Belleville, and the northern GTA (away from the shoreline), where mixing will reduce overall snowfall amounts.

Limited accumulation is expected near the shorelines of Lake Ontario and Lake Erie, as well as in Deep Southwestern Ontario, including Windsor and Chatham, where temperatures will likely remain too mild for significant snow accumulation.

After the system snow, attention will shift to the risk of snow squalls beginning Thursday and lasting several days into the weekend. Snow squalls are highly localized events, often producing intense snowfall within narrow bands only a few kilometres wide which can make it hard to pinpoint exactly who will see the worst conditions.

Current models suggest a dominant northwesterly wind direction for much of this period, historically favouring heavy snowfall in parts of Grey and Bruce counties off Lake Huron. Squalls off Georgian Bay are expected to target Simcoe County (Midland, Orillia, Barrie), Muskoka (Bracebridge, Gravenhurst), and the Kawartha Lakes region.

Locations such as Orillia, Midland, Wasaga Beach, Wingham, Mildmay, Hanover, Chatsworth, Owen Sound, and Flesherton could see up to 50 cm of snow by the end of the weekend. However, not all areas will experience these extreme totals due to the localized nature of snow squalls.

Stay tuned for updates as higher-resolution models provide more precise forecasts. For now, be aware that travel in snowbelt regions could be significantly impacted starting Thursday, with the potential for rapid snowfall accumulation and blowing snow leading to near-zero visibility and possible road closures.

December 22, 2024

A Nightmare Before Christmas as Snowstorm Targets Southern Ontario on Monday With Up to 10-20cm of Snow

December 22, 2024/ Brennen Perry

Are you dreaming of a White Christmas? Well, it looks like luck is on your side as a snowy system is poised to sweep across Southern Ontario just days before Christmas. However, this snowfall won’t come without consequences, as it is expected to bring a significant amount of snow to some areas and could disrupt holiday travel plans right before Christmas.

Snow is anticipated to start early Monday and persist throughout the day, bringing moderate to heavy snowfall across a wide area of the region. Central and Eastern Ontario are likely to bear the brunt of this storm, with total snowfall amounts ranging from 10 to 20cm expected by early Tuesday morning.

In contrast, Deep Southwestern Ontario and areas along the Lake Ontario shoreline, including the Greater Toronto Area GTA, are expected to experience lesser impacts from this system. This is primarily due to the majority of the precipitation staying further north, and any moisture reaching the south being met with slightly warmer air, resulting in wetter snow and reduced accumulation.

According to the latest data, initial bands of snow are projected to move into the Bruce Peninsula and Georgian Bay areas by mid to late morning on Monday. The snow will then spread eastward, encompassing Eastern Ontario and all regions by early afternoon.

The heaviest snowfall is likely to be concentrated east of Georgian Bay, possibly enhanced by minor lake effects. By late afternoon, snowfall will also begin in Southwestern Ontario, with a chance of some mixing, including ice pellets and wet snow, particularly in Deep Southwestern Ontario around Windsor.

The most challenging conditions are expected during the afternoon and evening hours, as steady snow covers much of Southern Ontario. Occasional moderate wind gusts up to 40 km/h may lead to blowing snow and reduced visibility. If travel is necessary during this time, exercise extreme caution, and consider postponing travel until Tuesday when conditions are expected to improve significantly.

Temperatures are forecasted to gradually warm up during the evening, approaching the freezing mark around Lake Ontario and Lake Erie. This may cause existing snow to transition to a mix of wet snow and rain, potentially resulting in lower snowfall totals in these areas.

Light snow will continue past midnight into early Tuesday morning but will diminish in intensity as the night progresses. Western regions should see snow taper off shortly after midnight, while Eastern Ontario may experience lingering snow until late morning.

Overnight, there is concern about rain mixing in along the Golden Horseshoe as temperatures rise further, potentially melting any earlier snow and jeopardizing the chances of a White Christmas in those areas. We will closely monitor this development as it unfolds.

Snowfall accumulation is expected to range from 10-20cm across Central and Eastern Ontario, including areas like Grey-Bruce, Barrie, Orillia, Huntsville, North Bay, and the Ottawa Valley. Some localized spots, particularly east of Georgian Bay and into the Ottawa Valley, could see up to 25cm of snow.

Further south and west, 5-10cm of snow is anticipated east of Lake Huron, extending into the Golden Horseshoe away from the shoreline, including cities like London, Woodstock, Kitchener, Guelph, Mississauga, and Orangeville.

Toronto, Oakville, Burlington, Hamilton, the Niagara region, and Deep Southwestern Ontario, such as Chatham, Sarnia, and Windsor, are expected to receive less than 5cm of snow. Windsor may see minimal snow if the transition to rain occurs earlier than anticipated. There remains a possibility for the GTA to exceed forecasted amounts if cold air persists and prevents mixing.

December 21, 2024

It’s a Christmas Miracle! A White Christmas Is Likely for Most of Ontario & Quebec This Year

December 21, 2024/ Brennen Perry

The month of December has truly delivered a winter wonderland for much of Ontario and Quebec, especially in the snowbelt regions of Ontario, which have seen significant snowfall from several rounds of snow squalls in recent weeks.

With Christmas just around the corner—less than five days away—the question on everyone’s mind is whether we’ll wake up to a White Christmas or a Green Christmas this year.

For clarity, Environment Canada defines a "White Christmas" as having at least 2 cm of snow on the ground at 7 a.m. Christmas morning. Unfortunately, in recent years, Southern Ontario’s holiday season has often been marked by the Grinch’s meddling, with last year seeing widespread "Grinchmas" conditions.

Currently, the snowpack across much of the region is quite substantial, particularly east of Georgian Bay, into Northern Ontario, and across Quebec. The good news for these areas is that the forecast suggests little to no rain or mild temperatures between now and Christmas, making a White Christmas virtually guaranteed.

However, the story is quite different for southern portions of the region, including Deep Southwestern Ontario and the Golden Horseshoe. These areas haven’t seen much in the way of significant snowfall accumulation this month, and the forecast includes a stretch of above-freezing temperatures on Christmas Eve and Christmas Day.

As a result, the odds of a White Christmas here depend entirely on whether snow can accumulate between now and Christmas morning.

Thankfully, hope isn’t entirely lost! A developing system is expected to move into Southern Ontario early Monday, continuing into Christmas Eve on Tuesday. Recent model updates have been promising for snow lovers, trending toward a stronger system that brings more widespread snowfall.

Current projections suggest this system could deliver 10–20 cm of snow across Central and Eastern Ontario. However, for those along the Lake Ontario and Lake Erie shorelines, including parts of the GTA and Niagara Region, snowfall amounts may be significantly lower due to temperatures rising above freezing during the day on Monday. This could lead to melting or even a mix with rain, reducing accumulation to just a few centimeters.

With temperatures hovering slightly above freezing through Christmas Eve, it’s uncertain whether any snow from this system will survive until Christmas morning in these areas.

WHITE CHRISTMAS REGIONAL BREAKDOWN

Central Ontario, including Muskoka, Tobermory, Bancroft, and Algonquin Park, has the best odds in Southern Ontario. These areas already boast a healthy snowpack from earlier systems and lake-effect snow, and Monday’s storm will only add to it. Temperatures are expected to remain below freezing, ensuring the snow sticks around. The chance of a White Christmas here is over 90%.

Eastern Ontario and areas near Lake Huron, including the Ottawa Valley and regions around Lake Simcoe, have a slightly lower chance at 75%. Eastern Ontario currently has little snow on the ground, but Monday’s system is expected to change that. Lake Huron’s shoreline, while already snow-covered, will face a brief warm-up Monday into Christmas Eve. While the snow is likely to hold, it isn’t guaranteed.

For areas like Sarnia, London, Kitchener, Guelph, and Belleville, the chance of a White Christmas is more uncertain at 50%. Everything depends on how much snow Monday’s system delivers and whether it can survive the milder temperatures leading into Christmas morning.

In the GTA, including Hamilton and northern parts of Niagara, the odds of a White Christmas are slim with a 25% chance. Without an existing snowpack and with limited accumulation expected from Monday’s storm, above-freezing temperatures are likely to melt any snow that does fall. However, if the storm overperforms or the warm-up is less intense, we could see a last-minute boost in probabilities.

Deep Southwestern Ontario, including Windsor and areas along the Lake Erie shoreline, is the least likely to see a White Christmas, with just a 10% chance. Monday’s system is forecast to bring minimal snow, and the prolonged warm-up will likely ensure a Green Christmas here.

Northern Ontario offers little drama in this forecast. With widespread snow on the ground and no significant warm-up in sight, the region enjoys a 90%+ chance of a White Christmas across the board.

Much of Quebec also looks set for a picturesque holiday. The exception is the Montreal area, which currently has limited snow on the ground. However, like Eastern Ontario, this should change once Monday’s system moves through.

This forecast remains preliminary and will be updated as we approach Christmas. Our final White Christmas forecast, set to be released on Christmas Eve, will factor in Monday’s storm and provide a clearer picture. If the snow cooperates, expect to see more 90%+ zones on the map. Stay tuned, and let’s hope for a festive, snow-covered holiday!

December 20, 2024

Pre-Christmas Squalls Could Bring Up to 25-50cm of Snow on Saturday to Parts of Southwestern Ontario

December 20, 2024/ Brennen Perry

As we approach the final weekend before Christmas, Southern Ontario is gearing up for the coldest air of the season so far. With the lakes still unfrozen after the unseasonably mild fall, conditions are setting up perfectly for the lake effect snow machine to roar back to life, particularly off Lake Huron.

Lake effect snow squalls are expected to develop as early as Friday evening along the southern shoreline of Lake Huron and persist through much of Saturday. Current indications suggest the heaviest snowfall will target the corridor between Sarnia and Strathroy. By the time the squalls taper off late Saturday, some areas could be buried under 25 to 50 cm of fresh snow.

This snowfall is promising news for those hoping for a White Christmas. With below-freezing temperatures expected to last through Tuesday, the snow should be deep enough to hold on despite a brief warm-up on Christmas Eve into Christmas Day when temperatures may climb above freezing.

Based on the latest data, a fairly intense snow squall is anticipated to form around midnight, likely affecting areas between Petrolia and Strathroy. However, the exact location of this band remains uncertain and will determine which areas see the most significant snow. The best bet at this time places the heaviest snow over Port Franks, Lambton Shores, and Kettle Point.

The squall is expected to persist through the overnight hours into early Saturday morning, bringing dangerous travel conditions in the affected regions. Rapidly accumulating snow combined with near-zero visibility will likely lead to road and highway closures. There’s also potential for the squall to extend further inland, possibly reaching areas northeast of Chatham along the Lake Erie shoreline.

Meanwhile, locations along the eastern shoreline of Lake Huron, from Kincardine to Grand Bend, may experience occasional bursts of heavy snow as the squall shifts and clips the shoreline.

By late Saturday morning and into the afternoon, the lake effect activity south of Lake Huron is expected to weaken as the band becomes more spread out and less organized. The squall should gradually diminish and retreat closer to the shoreline by Saturday evening, eventually fizzling out overnight into early Sunday morning.

In addition to the Lake Huron squalls, minor lake effect activity is possible south of Georgian Bay, including areas like Owen Sound, Meaford, and Collingwood. However, this activity is not expected to be as intense, with light to moderate snowfall likely throughout the day on Saturday.

When it comes to snowfall accumulation, variability is the nature of lake effect events. Narrow squalls can lock into a region and dump significant snow over a small area while sparing nearby locations.

We currently expect areas including Warwick, Watford, Forest, and Lambton Shores to receive between 25 to 50 cm of snow by the end of Saturday, with localized totals possibly exceeding 50 cm in some spots, although this is likely an overestimate.

The gradient will be sharp, with Petrolia and Grand Bend potentially seeing 15 to 25 cm. Sarnia and Strathroy, on the outskirts of the main activity, are likely to receive just 2 to 5 cm, although even a slight shift in the squall’s position could put these areas into the heavier snow zone.

Further up the eastern Lake Huron shoreline, locations from Kincardine to Grand Bend could see 5 to 15 cm of snow, with most areas leaning toward the lower end of that range.

South of Georgian Bay, including Owen Sound, Meaford, and Collingwood, snowfall is expected to range between 2 to 5 cm, with localized amounts up to 10 cm possible if the activity becomes more organized.

Elsewhere, the Niagara Region could pick up 2 to 5 cm of snow overnight into early Saturday morning as lingering precipitation from a previous system continues.

For the rest of Southern Ontario, no significant snowfall is expected this weekend. However, we are closely monitoring a potential snowmaker early next week between Monday and Tuesday, which has been trending stronger in recent model data. This system could bring heavy snow to parts of Southern Ontario, maybe sealing the deal on a White Christmas for many. We’ll provide more details on that in a separate forecast.

December 19, 2024

'Snow Day' Forecast: Slight Chance of School Bus Cancellations in the GTA on Friday

December 19, 2024/ Brennen Perry

A system is forecast to arrive in Southwestern Ontario late Thursday, bringing light to moderate snowfall to the region overnight and into Friday morning. Along with this system, a lake-effect snow band is expected to form early Friday morning, affecting parts of the Greater Toronto Area (GTA) west of Lake Ontario.

While the overall snowfall accumulation will not be particularly significant—most areas will see 2-5 cm, with localized amounts of up to 15 cm in the lake-effect snow zone—the potential for reduced visibility is a concern. This will be especially true for the stretch between Toronto and Burlington during the Friday morning rush hour. As a result, there is a possibility of school bus cancellations, though it remains uncertain.

The highest likelihood of cancellations is in the southern parts of Peel and Halton regions, where the most intense snow squall activity is expected. However, the probability is estimated at only 50%, as urban school boards in these areas typically require more substantial impacts to cancel buses. The decision will hinge on the strength of the snow band and whether it causes significant road issues when cancellation decisions are made in the early morning.

In surrounding areas, including Toronto and northern Halton, there is a slight chance (about 25%) of cancellations. While unlikely, the possibility cannot be entirely ruled out if conditions worsen unexpectedly.

Elsewhere in Southwestern Ontario, the probability of cancellations is very low to low. The system's expected snowfall alone is insufficient to prompt widespread cancellations. However, some localized areas may experience reduced visibility during the morning commute, which could lead to isolated decisions by individual school boards to cancel buses as a precaution.

For Central and Eastern Ontario, no school bus cancellations are anticipated, as these regions are not expected to see significant snowfall from this system.

As Friday marks the last school day before the holiday break, this will be our final snow day forecast for 2024. Thank you for relying on us for your snow day probability updates throughout the year. Our forecasts will resume the week of January 6th. Have a safe and happy holiday season!

December 19, 2024

Snow Squall May Disrupt Friday Morning Commute in the GTA; Locally 10-20cm of Snow Possible

December 19, 2024/ Brennen Perry

Southern Ontario has enjoyed a relatively calm week of weather, offering a welcome break for those still recovering from the heavy snow squalls that hammered parts of the snowbelt earlier this month. However, as the saying goes, all good things must come to an end, and this tranquil pattern is set to change as we approach the end of the week.

For a twist, the snowbelt won’t be the epicenter of the heaviest snowfall this time. Instead, the Greater Toronto Area (GTA), which has largely avoided winter’s worst so far, will be in the spotlight.

A weak system is forecast to sweep across Southern Ontario late Thursday into Friday, but the real story lies in a rare phenomenon: lake-enhanced snowfall and localized snow squalls along the western shoreline of Lake Ontario. These conditions could deliver a sudden 10-15 cm of snow, with localized totals nearing 20 cm in parts of the western GTA between Thursday night and early Friday morning.

Most other areas in Southern Ontario will see much less snow, with accumulations generally staying under 5 cm. As you move into Central and Eastern Ontario, snowfall will likely be limited to trace amounts. After the snow, attention will shift to an impending blast of Arctic air this weekend, bringing wind chills as cold as -30°C on Sunday and Monday.

The snowfall is expected to begin in Deep Southwestern Ontario on Thursday evening, with light to moderate bands moving eastward. While initial impacts will likely be minimal, drivers should still exercise caution as roads may become slushy with reduced visibility. By midnight, the snow will have reached the Golden Horseshoe, blanketing the region with light to moderate snowfall through the early hours of Friday.

A key feature of this system will be a concentrated band of heavy snow forming off Lake Ontario, likely impacting areas between Toronto and Burlington early Friday morning. This narrow band could initially affect Toronto and Mississauga before shifting southward into Oakville, Burlington, and eventually Hamilton. If this snow squall becomes stationary for an extended period, it could deliver intense snowfall rates of 2-4 cm per hour, rapidly accumulating 10-15 cm or more in a short time.

This timing is particularly concerning as the squall is expected to peak during Friday’s morning rush hour. Commuters in the western GTA should prepare for challenging conditions, including near-zero visibility and rapidly deteriorating roads. By early Friday afternoon, the lake effect activity should taper off as the system exits the province, though some lingering lake effect flurries may persist near Lake Ontario and along Georgian Bay's southern shoreline into Friday evening.

Given the highly localized nature of snow squalls, snowfall totals will vary significantly over short distances. Areas between Toronto and Burlington are most likely to see accumulations of 10-15 cm, with a slim chance of localized amounts reaching 20-25 cm if conditions align perfectly. That said, such higher totals are likely overestimations, though similar events in the past have exceeded expectations.

Beyond the GTA, snowfall amounts of 5-10 cm are expected in Hamilton, parts of the Niagara Region, and areas like the Dundalk Highlands and Georgian Bay’s southern shoreline, where some enhancement to the system is likely.

Elsewhere in Southwestern Ontario and regions around Lake Simcoe, 2-5 cm is expected, although there is some uncertainty about the system's moisture content, which could lead to slightly higher totals. Windsor, Central Ontario, and Eastern Ontario are expected to receive trace amounts of snow.

Looking ahead to the weekend, a surge of Arctic air will settle over Southern Ontario starting Saturday, with Sunday morning lows dipping well below -20°C across much of the region. In addition to the bitter cold, lake-effect snow is expected to return south of Lake Huron as early as Friday evening, potentially impacting areas like Sarnia, Petrolia, Port Franks, and Grand Bend.

These regions could see localized snowfall totals of 15-30 cm by Saturday. More details on this development will be provided in an upcoming forecast.

December 12, 2024

'Snow Day' Forecast: Extra Long Weekend for Some Students in Ontario as Squall Likely to Cancel Buses on Friday

December 12, 2024/ Brennen Perry

Intense snow squall activity is forecasted to bring a significant amount of snow to parts of the snowbelt region east of Lake Huron and Georgian Bay overnight and into Friday morning.

These squalls are expected to persist through the morning hours, creating hazardous conditions with near-zero visibility on the roads. Given these dangerous travel conditions, it is highly likely that many school boards will opt to cancel buses for Friday. For some areas, this would mark the second snow day in a row, as buses were already canceled on Thursday.

The highest confidence for school bus cancellations remains in areas like Grey-Bruce, Avon Maitland (Goderich), Simcoe (North), Trillium (Muskoka), and Near North (Parry Sound). With active snow squall warnings in place and the potential for over 50 cm of snow to accumulate overnight, there’s little doubt that buses will be unable to operate safely in these regions. We’re assigning a 90% probability of cancellations in these zones.

Outside the core snowbelt areas, the situation becomes less certain. For locations such as Listowel, Simcoe (West), and Trillium (Haliburton), we estimate a 75% chance of cancellations. While they are fairly likely, it’s not a guarantee. Regions including the rest of the Avon Maitland District School Board (AMDSB), Wellington, Dufferin, Simcoe (Central), Trillium (Kawartha), and East Parry Sound have a 50% chance of seeing cancellations, as snowfall in these areas is expected to be less intense or more variable.

For the rest of Southern Ontario, school bus cancellations on Friday are unlikely since the snow squall activity will remain localized to the snowbelt. This means a sharp drop-off in probabilities as you move farther away from the areas most heavily affected.

December 11, 2024

'Snow Day' Forecast: Blizzard Conditions on Thursday Likely to Cancel Many School Buses in Southern Ontario’s Snowbelt

December 11, 2024/ Brennen Perry

Snow squalls are forecast to develop late Wednesday and persist into Thursday, bringing substantial snowfall to areas around Lake Huron and Georgian Bay.

Strong wind gusts are expected to accompany the intense snowfall, prompting Environment Canada to issue a rare blizzard warning for parts of Grey, Bruce, and Huron counties. Meanwhile, other regions are under a strongly worded snow squall warning, with predictions of snowfall accumulation potentially reaching up to 80 cm in localized areas.

Given the expected hazardous conditions, it’s highly unlikely that school buses will be able to operate safely in the affected areas on Thursday. As a result, it is anticipated that many school boards will opt to cancel school buses and might even decide to close schools entirely, particularly in regions under a blizzard warning.

The highest likelihood of a ‘snow day’ applies to the entire Bluewater District School Board (BWDSB), Avon Maitland District School Board (AMDSB) - North Huron, Simcoe County District School Board (North and West weather zones), Trillium Lakelands District School Board (Muskoka region), and Near North District School Board (NNDSB - Parry Sound area).

These areas, which are under snow squall or blizzard warnings, have a greater than 90% chance of bus cancellations.

Surrounding regions, including the remainder of Avon Maitland District School Board (southern zones), Simcoe County District School Board (Central and South weather zones), Student Transportation Services of Wellington Dufferin (STWDSTS), and Trillium Lakelands District School Board (Kawartha Lakes and Haliburton regions), have a 50–75% chance of snow day cancellations.

Although these areas are still under warnings, they are not expected to experience the most severe conditions. While bus cancellations are still likely, the confidence level isn’t as high as in the core impact zones.

The probability of cancellations drops significantly outside the snowbelt, as the squalls are expected to remain highly localized. Eastern Ontario may be the only exception outside the snowbelt which has a low chance (10–25%) of cancellations.

While icy road conditions from an overnight freeze following earlier rainfall are possible, it is unlikely to be severe enough to prompt widespread cancellations. However, the possibility cannot be entirely ruled out.

December 11, 2024

Return of Squalls to Ontario’s Snowbelt This Week With Blizzard Conditions & Over 50cm of Snow Possible

December 11, 2024/ Brennen Perry

While the brief break from lake-effect snow earlier this month brought milder air and rain to the snowbelt regions, the respite appears to be short-lived.

Snow squall activity is expected to make a comeback as we approach the end of the week. With multiple days of snow squalls anticipated, we could once again see impressive snowfall totals, rivaling those from earlier this month.

Colder air will begin to filter into Southern Ontario from the northwest late Wednesday afternoon, dropping temperatures below freezing through the evening. This influx of cold air will trigger the development of lake-effect snow bands, with ideal conditions persisting through Thursday and into Friday.

Current projections suggest two primary zones will bear the brunt of the snow squalls: one east of Lake Huron and the other southeast of Georgian Bay. The Lake Huron squall is expected to impact southern portions of Grey and Bruce counties, including Owen Sound, Chatsworth, and Meaford. Meanwhile, the Georgian Bay squall will likely target central Simcoe County, extending northward into southern Muskoka.

Snowfall totals in the hardest-hit areas could exceed 50 cm, with the possibility of approaching the staggering 100 cm seen in Bracebridge and Gravenhurst earlier this month. Whether such totals materialize depends on whether any of the snow squall bands remain stationary for extended periods.

To make matters worse, strong winds are expected to develop late Wednesday and persist into Thursday morning. Gusts could reach 60–80 km/h, particularly in Grey-Bruce and Simcoe County, significantly reducing visibility and creating hazardous travel conditions.

Blizzard conditions may develop, and travel is strongly discouraged during this timeframe. School bus cancellations are almost certain along the Lake Huron and Georgian Bay shorelines on Thursday.

The lake-effect snow is expected to begin late Wednesday afternoon, with the first band forming off Lake Huron. Initially driven by northwesterly winds, this band will target areas near Goderich before shifting northward as winds veer to a more westerly direction by evening.

By midnight, the main Lake Huron squall is expected to become stationary, affecting areas from Wiarton southward to Port Elgin, Owen Sound, and Meaford. Simultaneously, snow bands will begin forming off Georgian Bay, initially targeting Wasaga Beach, Midland, and Orillia. These may briefly lift northward Thursday morning, potentially reaching Gravenhurst and Bracebridge.

The most intense conditions are forecast for late Thursday morning into the afternoon. Two main corridors of concern are expected: Owen Sound to Collingwood off Lake Huron, and Wasaga Beach to Orillia off Georgian Bay. Snowfall rates will be exceptionally high, and the squalls could remain locked in place for 6–12 hours, leading to rapid accumulation.

Strong wind gusts during this period could result in blizzard conditions, with near-zero visibility on roads. Road and highway closures are likely in the hardest-hit areas, especially on Thursday.

By late Thursday night, the snow squalls may shift into the Bruce Peninsula and Muskoka regions. While the bands are expected to weaken by Friday morning, lingering activity could still produce scattered flurries before tapering off completely by the afternoon.

As with previous lake-effect events, it’s important to remember that these snow squalls are highly localized. Narrow bands of snow, often only a few kilometres wide, can result in dramatically different conditions over short distances. One location might see over 50 cm of snow while areas just a few kilometres away remain relatively unscathed.

We currently have high confidence in two zones being hardest hit: southern portions of the Bruce Peninsula, including Owen Sound, Chatsworth, Meaford, and Flesherton, and areas west of Orillia, including Midland and Coldwater. Accumulations in these regions could exceed 50 cm, with totals potentially nearing 100 cm if squalls remain stationary long enough. A more conservative estimate is 50–75 cm.

A wider swath of Grey-Bruce, including Kincardine, Port Elgin, Hanover, Lion’s Head, and Tobermory, as well as much of Simcoe County and northern portions of Kawartha Lakes, Gravenhurst, and Beaverton, could see 25–50 cm. Not all areas in this zone will hit these totals, as much depends on the placement and movement of the snow bands.

Further south and away from the snowbelt, accumulation decreases rapidly. Barrie itself may largely miss the snow, although it could see up to 25 cm if the bands shift slightly. The Georgian Bay squall may extend inland at times, bringing heavy snow to Lindsay and Peterborough, with 10–20 cm possible in these areas.

For regions in other parts of the snowbelt, including Muskoka, Parry Sound, Haliburton, and parts of Dufferin, Wellington, Perth, and Huron counties, totals are expected to range from 10–20 cm. The Golden Horseshoe, including London, Kitchener, and Guelph, will likely see only light flurries, with less than 5 cm expected.

December 09, 2024

'Ice Day' Forecast: Widespread School Bus Cancellations Likely on Tuesday in Central and Eastern Ontario

December 09, 2024/ Brennen Perry

Following Monday's freezing rain that brought icy conditions across Central and Eastern Ontario, the risk of freezing drizzle persists through the overnight hours.

Environment Canada has issued widespread freezing drizzle advisories, warning that the slick conditions could extend into early Tuesday morning. With temperatures remaining near or just below the freezing mark overnight, untreated surfaces are expected to stay icy well into the morning.

As a result, it’s likely that many school boards, particularly in rural areas, will opt to cancel school bus services on Tuesday morning due to the hazardous road conditions.

The highest confidence for cancellations is in rural Eastern Ontario, where freezing drizzle is expected to still be occurring at the time decisions are made. These areas have been given a 90% chance of an “ice day.”

In the City of Ottawa, the likelihood is slightly lower at 75%, as the school board tends to be more conservative with cancellations in urban settings. However, the overnight icing should still be significant enough to prompt cancellations.

In Central Ontario, the Parry Sound and North Bay region has the highest probability of cancellations at 90%. The school board in this area is typically more weather-sensitive, and the lingering freezing drizzle almost guarantees that buses will be cancelled.

The situation becomes more uncertain for Muskoka, Haliburton, and Kawartha Lakes. Here, the freezing drizzle is expected to taper off shortly after midnight, but icy road conditions are likely to persist into the morning, with temperatures remaining near freezing.

After Monday’s decision to proceed with buses in some areas backfired for Trillium Lakelands—forcing adjustments to afternoon routes—the school board is likely to exercise more caution on Tuesday to avoid similar issues.

South and west of these regions, the chances of cancellations decrease significantly. Freezing drizzle is expected to end earlier in the evening, and temperatures are forecast to rise overnight, mitigating icy conditions. While cancellations cannot be entirely ruled out—particularly in Simcoe County—most other areas are unlikely to see disruptions to bus services on Tuesday.

December 08, 2024

'Ice Day' Forecast: Freezing Rain Threatens to Cancel School Buses on Monday in Parts of Southern Ontario

December 08, 2024/ Brennen Perry

Freezing rain is forecast to impact parts of Central and Eastern Ontario starting Monday morning and continuing throughout the day.

With Environment Canada issuing freezing rain warnings that highlight potential road hazards on Monday, it is highly likely that many school boards in the affected regions will choose to cancel bus services as a precaution.

The highest likelihood of an “ice day” is focused on areas northwest of the GTA, particularly in higher elevations, as well as regions around Lake Simcoe and into Eastern Ontario north of the Lake Ontario shoreline.

For school boards in these areas, there is a 75% to 90% chance of bus cancellations. While confidence in cancellations is high, there remains a small possibility that some boards might take a gamble due to the later expected start of the freezing rain. This uncertainty has kept the chances from being universally set at 90%.

The only area where we feel a solid 90% confidence level is the southern portion of the Tri-Board district. Historically, this region has been very proactive in response to any Environment Canada winter weather warnings, so the presence of a freezing rain warning is likely enough to prompt cancellations there.

Further north, including Muskoka, Haliburton, and the Ottawa Valley, messy weather may not arrive until later in the day. As of now, Environment Canada has not issued freezing rain warnings for these areas, which lowers the likelihood of bus cancellations.

Probabilities range from 25% to 50%, with just a 10% chance in the City of Ottawa. Urban cancellations in Ottawa typically require more severe conditions, so the lower chance is consistent with their past responses.

In contrast, Southwestern Ontario and the GTA are expected to see mainly rain with minimal freezing rain, making school bus cancellations in these regions highly unlikely.

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