April 12, 2024

Late Friday Wind Storm to Give Way to a Snowy Start to the Weekend in Parts of Ontario With Up to 10cm of Snow

April 12, 2024/ Brennen Perry

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The weather across Southern Ontario has been largely characterized by spring-like conditions, with temperatures soaring into the 20s and the season’s first widespread severe weather event occurring on Tuesday. This pattern continued into Thursday and Friday with heavy rainfall, but a change is on the horizon for the weekend.

Persistent rain across Southern and Northern Ontario on Friday is expected to transition to snow overnight into Saturday morning. For most areas, the snow should melt upon contact, with limited accumulation. However, higher elevations around Georgian Bay and into Northeastern Ontario could see snow accumulations of 5-10cm by Saturday afternoon.

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Before the snow arrives, strong wind gusts are anticipated to develop by Friday afternoon, continuing overnight into Saturday morning.

The strongest gusts, possibly exceeding 90 km/h, are expected along the Lake Huron shoreline and the southeastern shoreline of Georgian Bay.

The hardest hit regions include Kincardine, Goderich, Grand Bend, and Collingwood which could experience wind strong enough to potentially cause damage, including power outages.

In Southwestern Ontario and the Golden Horseshoe, wind gusts are predicted to range from 70 to 90 km/h. Eastern Ontario will see less impact, with wind gusts expected to stay below 70 km/h. The wind is expected to subside by sunrise on Saturday.

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Northeastern Ontario will also experience strong gusts from Friday afternoon into the evening, with the areas directly north of Georgian Bay like Elliot Lake, Manitoulin Island, and Sudbury seeing the strongest gusts, approaching 80-90 km/h.

Widespread gusts of 70-80 km/h are expected in the rest of Northeastern Ontario, with lower gusts further north and west.

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As colder air sweeps into the region overnight, temperatures across Central Ontario and the Dundalk Highlands are likely to hover around the freezing mark into Saturday morning. This will cause the existing rain to transition into wet snow or flurries starting Friday evening.

With temperatures near freezing and recent rainfall, it’s questionable if the snow will stick or accumulate. The best chance for accumulation is in higher elevations such as Shelburne, Orangeville, and the Blue Mountains, where up to 5-10cm of snow could accumulate by Saturday morning.

Surrounding areas extending into Central Ontario, including Barrie, Orillia, Muskoka, and the Kawartha Lakes, might see minor accumulations of 2 to 5cm. This will vary based on local conditions, which could impact the snow's ability to accumulate. Regardless, the area is likely to experience sloppy conditions and icy roads as near-freezing temperatures cause existing rain on roads to freeze and create black ice.

The rest of Southern Ontario will see less than 2cm of snow or no snow at all, as will be the case in Deep Southwestern Ontario, the Golden Horseshoe, and Eastern Ontario.

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Colder temperatures in parts of Northeastern Ontario will allow for better snow accumulation, with areas like Timmins and Cochrane expecting up to 10cm of snow. The rest of Northeastern Ontario, except for regions north of the Georgian Bay shoreline, could see between 5-10cm of snow by Saturday afternoon. Less than 5cm is expected near the Georgian Bay shoreline due to warmer temperatures.

Snowfall is expected to cease across all parts of Ontario by early Saturday afternoon. The weekend will remain chilly for most areas, with temperatures stuck in the single digits on Saturday and Sunday, except in Deep Southwestern Ontario.

Windsor and Chatham may experience a pocket of warmer air, especially on Sunday, with temperatures potentially reaching the 20s and a risk of thunderstorms. The rest of Southern Ontario will see daytime highs in the mid to upper single digits on Sunday.

April 02, 2024

Winter Storm Threat Looms for Ontario With Up to 30cm of Snow and 60mm of Rain by Thursday

April 02, 2024/ Brennen Perry

The beginning of April in Ontario is setting the stage for a dramatic shift in weather, as a moisture-laden system promises a variety of conditions across the region. This shift includes the potential for flooding rains, with predictions of 40 to 60mm of rain in parts of the Golden Horseshoe.

In addition, areas of Central, Eastern, and Northern Ontario are on track for significant snowfall, with totals ranging from 20 to 35cm in the most affected areas!

As outlined in our previous forecasts, this bout of active weather kicked off with strong wind gusts on Tuesday afternoon, expected to persist into the night.

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With the wind gradually subsiding, our attention now shifts to the substantial moisture being pumped into our region from the Gulf of Mexico. Initially, this precipitation will begin as heavy rain, with intense downpours expected overnight and into Wednesday morning across the Greater Toronto Area, extending into Central and Eastern Ontario.

However, by late Wednesday, colder air from the northwest will sweep in, prompting a gradual transition from rain to wet snow by the late afternoon in parts of Central and Eastern Ontario. Northeastern Ontario, already under colder air by the morning, may experience snow for the duration of this event.

The challenge in forecasting this system lies in the temperatures hovering near the freezing point, significantly impacting snow accumulation. Additionally, model predictions vary on the timing of the transition from rain to snow, some suggesting it won't occur until late Wednesday evening, while others indicate it will occur around 2 to 5 PM.

By Wednesday night, most regions, including the Golden Horseshoe, are expected to have transitioned to wet snow, with light to moderate snowfall persisting into Thursday morning and afternoon, concluding by Thursday evening.

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Elevation will be a crucial determinant of snowfall totals, with the highest accumulations forecasted southwest of Ottawa in Eastern Ontario's elevated areas. This includes Bancroft, Barry’s Bay, Algonquin Park, and Renfrew, with expected snowfall totals ranging from 20 to 35cm by Thursday's end.

For the Ottawa Valley, including Ottawa, Cornwall, Brockville, and Pembroke, snowfall totals are more uncertain, ranging from 10 to 25cm. This variability will depend on local dynamics and the ability of snow to stick to the ground. There is the potential that some areas will exceed our forecast if the snow can stick more efficiently to the ground.

Further south and westward, snowfall totals are expected to range from 5 to 15cm, including Kingston, Peterborough, Huntsville, and Sundridge. Local areas north of the Greater Toronto Area, particularly along the higher elevations of the Oak Ridges Moraine and Dundalk Highlands, may also see up to 10 to 15cm. This forecast is heavily dependent on temperatures, which may not drop below freezing until Thursday morning, affecting accumulation.

Areas east of Georgian Bay and away from Lake Ontario's shoreline are likely to exceed 5cm but should remain under 10cm. Regions directly along the Lake Ontario shoreline and parts of Southwestern Ontario will experience less than 5cm of snow, as rain will dominate these areas.

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In addition to significant snowfall in Central and Eastern Ontario, significant rainfall is anticipated along Lake Ontario's shoreline, including Prince Edward County, Oshawa, Toronto, Mississauga, Burlington, Hamilton, and Grimsby, with potential totals ranging from 40 to 60mm. This rapid accumulation, especially in urban areas prone to flash flooding, poses a substantial flooding risk.

Rainfall totals for the rest of the Golden Horseshoe, extending to the Dundalk Highlands and the Bruce Peninsula, are projected to range from between 30 to 50mm. Further north and east, where more snow is expected to mix in, rainfall totals of 20 to 40mm are likely.

Southwestern Ontario is expected to see lower rainfall totals of 10 to 30mm, with Deep Southwestern Ontario receiving less than 15mm.

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In Northern Ontario, heavy snow is the main concern, with the highest totals just north of Sudbury, anticipating 20 to 35cm of snow from Wednesday morning through Thursday afternoon.

For Sudbury and North Bay, snowfall predictions range from 10 to 25cm. Lower amounts are expected towards Georgian Bay due to rain mixing in, while totals will decrease sharply further north and west due to limited moisture.

March 30, 2024

Potential Snowy Start to April With Up to 20cm in Parts of Southern Ontario Starting Tuesday

March 30, 2024/ Brennen Perry

April Fools' Day might be on Monday, but the first week of April is shaping up to be no laughing matter in terms of weather for Southern Ontario. Starting Monday, the lower Great Lakes region is expected to be impacted by a series of systems throughout the week.

The initial two systems are projected to track south of the border, impacting Ohio and Pennsylvania primarily. There's a risk of severe weather on Monday and Tuesday, with a possibility it could extend into Deep Southwestern Ontario. However, the cold waters of Lake Erie should keep most of the severe risk south of the border. We will be monitoring and will have a forecast if it becomes more certain to have an impact on our region.

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These systems are set to bring heavy rain across the Lake Erie shoreline, from Sarnia to the Niagara Region and southward, with some areas potentially receiving 10-20mm of rain from Sunday night into Tuesday morning.

By late Tuesday, a third system is expected to sweep across Southern Ontario, bringing heavy rain throughout Tuesday afternoon and evening for most regions. Temperatures are set to drop from the low to mid-single digits to around or slightly below the freezing mark, causing the rain to transition to snow overnight into Wednesday morning.

The extent of this changeover, however, remains uncertain. Areas near the Lake Ontario shoreline and Deep Southwestern Ontario are likely to remain warm enough to prevent significant snow accumulation. In contrast, Central and Eastern Ontario, along with the higher elevations of the Dundalk Highlands northwest of the GTA, may experience sustained snowfall.

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This snow is expected to persist into Wednesday, with moderate to heavy snowfall continuing into the evening. Strong wind gusts may also contribute to blowing snow and reduced visibility in some areas. Light snow may linger into Thursday for Central and Eastern Ontario, but it won’t lead to much accumulation.

This forecast is preliminary and subject to changes as the system's path and temperatures near the freezing point could significantly affect overall snowfall accumulation.

As of now, Central and Eastern Ontario, including the Ottawa Valley and Muskoka, are anticipated to see 10-20cm of snow. The higher elevations of Algonquin Park and the Ottawa Valley are expected to be closer to the 20cm mark, with Ottawa and Muskoka likely receiving 10-15cm.

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The Dundalk Highlands area could see heavier snowfall, with Orangeville and Shelburne potentially receiving the most, possibly up to 10-20cm. However, this forecast is less certain due to temperature variations that may prevent freezing and cause some melting.

The rest of Central Ontario and the northern part of the GTA could receive 5 to 10cm by Thursday, with the possibility of higher totals if temperatures drop further than currently expected.

Areas near Lake Ontario's shoreline, the Niagara region, and the Lake Erie shoreline are expected to see less snow, with less than 5cm of accumulation. However, significant rainfall poses a concern for these areas, with potential localized flooding due to upwards of 50mm of rain.

We will continue to monitor the latest data and provide a more detailed forecast shortly. Remember, this forecast is very preliminary and could change significantly by Tuesday.

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March 21, 2024

Biggest Snowfall of the Season Possible in Parts of Southern Ontario Including Toronto on Friday With Up to 10-20cm of Snow

March 21, 2024/ Brennen Perry

Spring may have officially started earlier this week, but the weather across Southern Ontario has been anything but spring-like. We've experienced lake-effect snow over the last few days, along with temperatures near or below the freezing mark. This marks a significant change from the pattern observed throughout the winter, especially towards the end of winter in February and early March, which saw unusually mild conditions.

Now in late March, we're tracking a potential system that could bring the most significant snowfall accumulation of the season for some regions. While this might sound daunting, it's important to remember that some areas have yet to record even 10cm of snow in a single day this season, so the bar for the 'snowiest day of the season' title is relatively low.

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This system, starting Friday morning and continuing through the day into early Saturday morning, could result in widespread snowfall totals between 10 to 15cm, with possible accumulations reaching up to 20cm. This swath of heavy snow is expected to stretch from the Lake Huron shoreline through the Golden Horseshoe and into parts of Eastern Ontario along the St. Lawrence River.

The initial bands of snow are expected to move into Southwestern Ontario from Michigan during the late morning hours on Friday, spreading eastwards throughout the early afternoon. By late afternoon, the snow will cover much of the Lake Huron shoreline and extend towards the Greater Toronto Area (GTA), ranging from light to moderately heavy snowfall.

There remains some uncertainty regarding the system's track, with some models predicting the heaviest snow band stretching from Kincardine to around Lake Simcoe, while others suggest a more southern route from Grand Bend through Kitchener and into Toronto. The consensus among the models leans towards the southerly track, which we are adopting for now, but adjustments may be necessary if there are shifts in the track closer to the event.

Lake enhancement could also increase snowfall rates off the southwesterly shoreline of Lake Ontario from Toronto to Hamilton on Friday evening, extending overnight into Saturday morning. Another band of heavy snow is expected to move into the Golden Horseshoe, particularly focusing on the Niagara region just before midnight, which is when the highest snowfall rates are anticipated.

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Additionally, there's a potential risk for freezing rain and mixed precipitation along the Lake Erie shoreline and in parts of Deep Southwestern Ontario, including Windsor and Chatham. Currently, the threat of freezing rain seems minimal, but it could change, with some models suggesting more prolonged icing along the shoreline.

The system will progress into Eastern Ontario just after dinner on Friday, with the heaviest snow expected to concentrate along the Hwy 401 corridor from Belleville to Cornwall, persisting into the early hours of Saturday with the most challenging conditions occurring overnight.

Snowfall is expected to taper off from west to east, concluding in Eastern Ontario by early Saturday afternoon.

Based on the current data, snowfall totals are anticipated to range from 10 to 15cm in the hardest-hit regions, including Goderich, Kitchener, Guelph, Hamilton, Toronto, Niagara Falls, Kingston, Brockville, and Cornwall.

Certain areas within this zone could see up to 20cm due to lake enhancement off Lake Ontario, hence the forecast range of 10 to 20cm on our map. If confidence in lake enhancement increases with later model runs, we may need to adjust the forecast up to 15-25cm for parts of the Western GTA.

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With Toronto expected to receive at least 10cm of snow, this event has the potential to be the snowiest day of the winter thus far, which is quite surprising given that it's already late March. The highest daily snowfall total recorded at Toronto Pearson Airport this winter was 6.4cm on February 15th.

Although Southern Ontario has seen several snowmakers this winter, especially in the snowbelt, the Toronto area has largely been spared, with temperatures along the Lake Ontario shoreline quickly transitioning any snow to mixed precipitation.

We do not anticipate mixed precipitation being a factor for the Toronto area with this system, as temperatures are expected to remain below the freezing mark throughout the event.

Lower snowfall totals are expected to the north, with the Barrie, Orillia, Peterborough, Bancroft, and Ottawa areas likely to see between 5 to 10cm of snow. The same is true for Southwestern Ontario, from Sarnia to London, where totals are unlikely to exceed 10cm.

Less than 5cm of snow is expected in northern Central Ontario, including Muskoka, due to the moisture from the system dropping off and along the Lake Erie shoreline, where mixed precipitation could result in lower snowfall totals.

March 20, 2024

Lake Effect Snow Targets Parts of Southern Ontario With Over 20cm of Snow Possible by Thursday

March 20, 2024/ Brennen Perry

Environment Canada has issued widespread snow squall warnings around Lake Huron and Georgian Bay today. The warning was issued because of the current frontal squall sweeping through the region, coupled with additional lake-effect snow expected to develop later today, persisting into Thursday morning.

Our forecasts often highlight the variability of snowfall totals during snow squall events due to the narrow bands involved. It's not uncommon for one area of a town to experience significant snowfall while an area just 5-10 minutes away receives barely any snow.

Predicting the precise location of these snow bands is challenging as even a slight shift in wind direction can significantly impact the outcome. Typically, we can provide a general idea of which regions will be most affected.

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However, this occasion is different, and we will not be producing our standard polygon forecast map. The three main high-resolution models we rely on for lake effect snow forecasts, HRRR & NAM from the United States and Canada's HRDPS. These models are showing significantly different outcomes, making it impossible for us to offer a forecast with confidence. We believe it wouldn't be responsible to predict something we're not sure about.

Instead, we're sharing the raw model data from these three models, allowing you to see the range of potential scenarios for your location and prepare accordingly. It's important to remember that model data often overestimates actual snowfall, so the amounts shown are likely too high. However, this data is useful for understanding where each model predicts the heaviest snowfall will occur.

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The models mainly diverge regarding the Georgian Bay squall expected to develop this evening and continue into Thursday morning. This squall is predicted to come ashore between Wasaga Beach and Collingwood, extending inland towards Barrie and possibly reaching the northern York Region.

The HRRR model estimates the most snow from this squall, suggesting over 50cm in areas just southwest of Barrie, including Wasaga Beach, Angus, and Alliston.

Keep in mind, that this is just raw model data, and the estimated 50cm is probably an overestimation, especially since the HRRR model tends to overpredict lake effect snow events. Nevertheless, if the HRRR model is accurate, this region could see 20-40cm of snow by Thursday.

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On the other hand, the NAM and HRDPS models predict a much weaker squall off Georgian Bay, with snow totals more in the range of 5-10cm (locally 15cm), and the NAM showing barely a few centimetres. This illustrates the wide variety of potential outcomes, from a few centimetres to over 20cm of snow.

Regarding the Lake Huron shoreline, there is slightly more consensus on overall accumulation, with all three models predicting over 20cm of snow between Hanover and London. However, this prediction still represents a very narrow band, meaning not everyone will see significant snow, and some may see only a few flakes.

Southern Grey and Bruce counties, along with Huron and Perth counties, are expected to bear the brunt of the heaviest snowfall, with totals ranging from 10-20cm and localized pockets possibly receiving 25-30cm. This includes areas like Kincardine, Goderich, Hanover, Listowel, Wingham, and Stratford. The Kitchener and Guelph region may also experience bursts of heavy lake-effect snow, with accumulations ranging from 5 to 10cm.

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Further south, all models concur on another band of lake effect snow southeast of Lake Huron, stretching from Grand Bend to the London area. This band is not expected to be as prolonged or intense as those further north, so snowfall totals will be more in the range of 5 to 10cm by Thursday afternoon.

As the lake effect snow winds down by Thursday's end, our focus shifts to a system arriving late Friday into Saturday that could bring significant snowfall to parts of Southern Ontario. There's some disagreement on the exact path of the system, and temperatures will hover near the freezing mark, potentially leading to mixed precipitation in some areas, affecting overall snowfall totals.

At this stage, a widespread snowfall of 10-20cm, with local amounts up to 25cm, seems fairly likely in parts of Southwestern Ontario and possibly extending into the Golden Horseshoe. We will issue a preliminary forecast soon, so stay tuned for updates!

March 19, 2024

Ontario to Welcome the First Day of Astronomical Spring With Up to 15-25cm of Snow Between Tuesday & Wednesday

March 19, 2024/ Brennen Perry

As we close the chapter on winter with what seemed like an early spring, Ontario is being reminded that winter isn’t going out without a bang. The first day of astronomical of spring arrives on Tuesday, March 19, 2024, at 11:06 PM EDT, but it certainly won’t look like it…

Despite a month filled with unseasonably warm temperatures that saw many regions experience their first 20°C days of the year—quite unusual for this early in the season—the final hours of winter won’t let us forget the season isn’t finished just yet!

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A weak system is set to track across Northern and Southern Ontario from Tuesday morning and persist throughout the day. Although this system lacks significant moisture, lake enhancement is expected to amplify snowfall totals in parts of Northeastern Ontario and the regions surrounding Lake Huron and Georgian Bay. We're anticipating overall snowfall accumulation of 10-20cm, with localized areas possibly seeing up to 25cm by Wednesday morning.

While the bulk of the snow will diminish by Wednesday, localized snow squalls could continue to dust the Grey-Bruce and Muskoka regions with an additional 5-15cm of snow by Wednesday's end. However, these higher amounts will be highly localized.

Snowfall has started in parts of Northwestern Ontario, with the system moving south and east overnight. Light snow is expected for most regions throughout Tuesday, except near Lake Superior, Georgian Bay, and Lake Huron, where lake enhancement will result in heavier snowfall.

Particularly northwest of Georgian Bay and east of Lake Superior, Tuesday morning and afternoon will see locally intense snow bands causing reduced visibility and rapid accumulation. These conditions will extend through parts of Northeastern Ontario and into Central Ontario.

By Tuesday night, we expect the system-induced snow to taper off shortly after midnight. However, with cold temperatures prevailing, lake effect snow is likely to continue into Wednesday. This includes a potentially strong snow squall in the Grey-Bruce area, reaching into parts of Simcoe County and the Northern GTA by Wednesday morning.

The snow squall is forecasted to be brief as a wind shift will cause it to move southward and gradually dissipate. Another bout of light snow is anticipated across Southern Ontario on Wednesday afternoon as lake-effect snow becomes more widespread due to the shifting wind direction.

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The heaviest snowfall, primarily due to lake enhancement, is expected east of Lake Huron and Georgian Bay. Areas like Owen Sound, Wiarton, Parry Sound, Huntsville, and Sundridge could see totals of 15 to 25cm by Wednesday's end. Owen Sound, in particular, may receive upwards of 30cm, especially if the Wednesday morning squall intensifies as some models suggest.

Neighbouring areas such as Bracebridge, Orillia, Collingwood, Hanover, Kincardine, and Tobermory are projected to receive 10 to 20cm of snow. However, due to the variability introduced by lake enhancement, snowfall distribution will be highly unpredictable, with some locations potentially receiving less than 10cm.

Locations like Goderich, Orangeville, Barrie, Peterborough, and Kingston should brace for 5 to 10cm of snow. These areas will benefit from some lake enhancement, but limited overall moisture will keep totals below 10cm.

Eastern, Southwestern Ontario, and the Golden Horseshoe, including the Greater Toronto Area and Extreme Southwestern Ontario, are expected to see about 5cm of snow over the next two days, with some areas receiving only a few centimetres.

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Northeastern Ontario, extending into Northwestern Ontario, could see 15cm to 25cm of snow by the end of Wednesday. This includes Sault Ste. Marie, Wawa, Marathon, Geraldton, Timmins, and Kirkland Lake.

The remainder of Northeastern Ontario will see totals between 10 to 20cm, though regions north of Georgian Bay like Elliot Lake and Sudbury may receive less than 10cm due to diminished lake enhancement.

Northwestern Ontario will experience lesser impacts, with Thunder Bay expecting 2 to 5cm of snow, while Kenora and Dryden will see less than 2cm.

March 09, 2024

Winter Is Not Done Yet! Parts of Southern Ontario Could See Up to 10-20cm of Snow by Monday

March 09, 2024/ Brennen Perry

Southern Ontario's recent spell of balmy weather made it feel like an early spring, yet winter has swung back into our forecast. A return of colder air has arrived just in time for the weekend, bringing a fresh batch of lake effect snow—aided by the unusually open waters after our mild winter.

Lake effect snowfall is expected to predominantly impact the southern shores of Lake Huron starting late Saturday and persisting into Sunday. The most affected regions could amass snow totals nearing 15 to 20cm by the end of Sunday.

Simultaneously, the outer bands of a system tracking up the Northeastern United States might deliver accumulating snow, primarily to Ontario's far eastern regions beyond Ottawa. These areas could see accumulations of 10 to 15cm by Monday morning.

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As of Saturday evening, we've witnessed a temperature dip across Southern Ontario, with expectations for the mercury to descend below freezing overnight. This shift sets the stage for lake effect snow development along the Lake Huron and Georgian Bay shorelines, particularly overnight and into Sunday morning.

Heavy lake effect snow is forecasted for areas stretching from Goderich to southward through Grand Bend and even into London, and south of Georgian Bay, encompassing the Meaford and Collingwood area.

The peak of this lake effect snow event is predicted for the pre-dawn hours on Sunday, continuing into early afternoon and gradually lessening by evening.

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Snow Squall Accumulation Disclaimer

Forecasting the exact snowfall accumulation for a specific location in a lake-effect snow event is extremely challenging. This is because of the highly localized nature of snow bands, which can lead to significant variance in totals even over short distances.
Therefore, you may notice our forecast shows significantly more snow than your weather app (including our own app). App-based forecasts often struggle with lake effect snow events due to their localized nature and reliance on data focused on larger macro-level weather events. This results in a failure to accurately capture the squalls, which operate at a micro-level, leading to intense snowfall totals.
Our forecast may still be off if the wind direction varies slightly from what the models predict, causing the snow squall band to form further north or south. That's why our forecasts use broader zones to account for this variability, meaning not everyone within these zones will see the significant totals. Essentially, we're indicating that a location within this area could see the forecasted amount.

The latest data indicate the most substantial snowfall will be found in areas like Goderich, Grand Bend, Lucan, and London, where totals may surpass 10cm, with localized areas potentially receiving 15-20cm. Elevated regions southwest of Collingwood are also likely to see over 10cm of snow.

Neighbouring regions such as Port Elgin, Wingham, St. Thomas, Meaford, and Collingwood might see up to 10cm, depending on the strength of the lake-effect snow. Lesser amounts, under 5cm, are anticipated for the rest of Southwestern Ontario and the Golden Horseshoe.

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Beyond the lake effect, heavy snow is forecasted to develop overnight in far Eastern Ontario as outer bands of precipitation from the slow-moving Eastern Seaboard system linger in the region.

Persistent snowfall will continue across areas east of a line from Kingston to Ottawa throughout Sunday, possibly continuing overnight before fizzling out just after Monday's sunrise.

Regions including Hawkesbury, Alexandria, and Cornwall could see totals exceeding 10cm by Monday morning. The area from Ottawa south to Brockville might approach snowfall close to 5cm. As we move westward, expected accumulations will quickly decrease, with less than 5cm forecasted due to the sharply declining precipitation gradient.

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March 08, 2024

Messy System Targets Ontario This Weekend With Significant Rain to the South and Heavy Snow to the North

March 08, 2024/ Brennen Perry

The opening week of March has been notably calm in Southern Ontario, with minimal active weather events and a generous serving of above-seasonal warmth and predominantly clear skies. A few rain spells have visited us over the last several days, with temperatures occasionally leaping into the 20s, setting records on Tuesday and Wednesday in some locations.

Yet, as we move towards the weekend, we anticipate a shift, with a looming system poised to bring substantial rainfall across Southern Ontario. In contrast, those in Northeastern Ontario should ready themselves for a considerable snowfall, with some areas potentially seeing up to 30cm.

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Following the departure of this system by late Saturday, a period of sub-freezing temperatures will return to Southern Ontario on Sunday, extending into Monday. This shift sets the stage for the possibility of snow accumulation in parts of Central Ontario, particularly Eastern Ontario and near Lake Huron and Georgian Bay, at the onset of next week.

Southwestern Ontario has already begun to experience heavy rain on Friday evening, anticipated to last into Saturday. The heaviest downpours are expected overnight and into the morning hours. The rain will start around midnight for Eastern and Central Ontario and is likely to persist into early Saturday afternoon.

Accompanying the rain on Saturday will be a surge of mild air, with daytime highs expected to reach the upper single digits, and potentially the low teens throughout Southern Ontario. While the Northern parts of the province will see a more resilient cold air mass, resulting in snow rather than rain.

Northeastern Ontario will see the onset of snow around midnight, with the mixing line expected near Elliot Lake to slightly north of Sudbury. Areas north of the line, including Chapleau and Timmins, will experience significant snowfall overnight into Saturday morning, with intense snow at times throughout the day.

Both the rain in the south and snow in the north will diminish as the evening progresses, as the system departs our region. By Saturday evening, a switch from rain to snow is possible in the northern regions of Central and Eastern Ontario. However, with the ground still saturated from previous rains and temperatures hovering just above freezing, significant accumulation is not anticipated.

Overnight into Sunday, light to moderate snowfall may occur in regions traditionally affected by lake-effect snow around Lake Huron and Georgian Bay. Eastern Ontario might also receive some flurries from the lingering bands of system-related precipitation. Currently, we predict a few centimetres of snow at most, though certain areas along the Lake Huron shore and south of Georgian Bay could receive up to 5-10cm. A more detailed forecast for Sunday's snow will be released on Saturday.

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Regarding total rainfall, Central and Eastern Ontario are set to receive the highest totals, with 25 to 40mm expected by Saturday's end, which may cause localized flooding. Widespread totals of 15 to 30mm are projected across most of Southern Ontario. Areas near the Golden Horseshoe, along the southern Georgian Bay shoreline, and over Algonquin Park could see a dry pocket leading to slightly less rain, with 10 to 20mm anticipated.

As for Northeastern Ontario, snow will be the dominant story with snowfall totals of 20 to 30cm in a broad swath encompassing Timmins, Kirkland Lake, Cochrane, and Kapuskasing. A sharp drop-off in accumulation is forecasted closer to the rain-snow mix to the south and drier areas to the north.

The Chapleau area can expect 10 to 20cm of snow, while less than 10cm is predicted for North Bay, Sudbury, Elliot Lake, and Sault Ste. Marie, with rain as the primary form of precipitation for those regions.

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February 28, 2024

From Record-Breaking Heat to Blizzard; Snow Squalls Could Dump Upwards of 15-30cm on Parts of Ontario by Thursday

February 28, 2024/ Brennen Perry

The last 48 hours have been a weather whirlwind across Southern Ontario, beginning with thunderstorms and the season's first 20°C temperature recorded in Windsor on Tuesday.

This brief 'heatwave' has abruptly ended, ushered out by a sharp cold front that sent temperatures tumbling on Wednesday. By overnight into Thursday morning, we're bracing for wind chills that could make it feel like it's in the -20s!

The return of Arctic air to Southern Ontario typically means one thing: Mother Nature is about to fire up the lake effect snow machine over the usual snowbelt regions. The upcoming day will be no exception as we anticipate intense snow squalls affecting the Lake Huron and Georgian Bay shorelines, potentially dumping 15 to 30cm of snow by Thursday's end. Accompanying the heavy snow will be strong wind gusts, leading to blowing snow and localized blizzard conditions over the next 24 hours.

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The cold front in question has already made its way across our region as of early Wednesday afternoon, with temperatures in Southwestern and Central Ontario swiftly falling below freezing. This trend is expected to persist, bringing even colder air by evening.

Lake effect snow is set to begin this afternoon, initially starting off as disorganized and light. Expect light to moderate snowfall along the Lake Huron and Georgian Bay shorelines through the afternoon and evening. In Northeastern Ontario, snow squall activity is underway, focusing on the southeastern shoreline of Lake Superior between Wawa and Sault Ste. Marie.

As we move into Wednesday evening, models predict a more intense, focused squall developing between Wiarton and Kincardine, extending over Georgian Bay to come in land around Simcoe County. The Sault Ste. Marie region will also face relentless snow squall activity through the evening and overnight.

This squall is particularly noteworthy due to its significant moisture content, benefiting from an optimal fetch across Lake Superior, Lake Huron, and Georgian Bay. Consequently, we expect high snowfall rates, with the potential for the band to reach far inland, possibly affecting parts of the Northern GTA.

Driving conditions in Grey, Bruce, and Simcoe Counties, among other regions, will become treacherous overnight into Thursday morning. With wind gusts of 60 - 80 km/h, near-zero visibility and rapid snow accumulation are anticipated, raising the possibility of highway closures overnight.

Further south, areas away from Lake Huron like Listowel and Hanover may experience more scattered, less intense lake effect snow compared to the squall to the north.

By sunrise on Thursday, the main snow squall is expected to begin dissipating, although it will likely persist through the morning and early afternoon. The shifting wind direction may cause the squall to drift, dispersing snowfall over a broader area.

Lake effect snow activity off Lake Superior and Lake Huron/Georgian Bay is anticipated to wind down by mid to late afternoon on Thursday, as a slight temperature rise creates conditions less conducive to lake effect snow development.

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Snow Squall Accumulation Disclaimer

Forecasting the exact snowfall accumulation for a specific location in a lake-effect snow event is extremely challenging. This is because of the highly localized nature of snow bands, which can lead to significant variance in totals even over short distances.
Therefore, you may notice our forecast shows significantly more snow than your weather app (including our own app). App-based forecasts often struggle with lake effect snow events due to their localized nature and reliance on data focused on larger macro-level weather events. This results in a failure to accurately capture the squalls, which operate at a micro-level, leading to intense snowfall totals.
Our forecast may still be off if the wind direction varies slightly from what the models predict, causing the snow squall band to form further north or south. That's why our forecasts use broader zones to account for this variability, meaning not everyone within these zones will see the significant totals. Essentially, we're indicating that a location within this area could see the forecasted amount.

The areas hardest hit in Southern Ontario are expected to be Wiarton, Owen Sound, Chatsworth, Meaford, Collingwood, and Barrie, with 15 to 30cm of snow accumulation possible by Thursday's end.

It's important to note that models significantly diverge on the strength of these squalls, with some indicating potential for up to 50cm of snow in localized areas. Thus, there's a possibility for some regions, especially if the squall remains stationary overnight and into Thursday morning, to experience higher than anticipated snowfall totals.

Surrounding areas such as Port Elgin, Hanover, Keswick, and Orillia are generally expected to see 10 to 20cm, although the snow accumulation gradient will be extremely tight, meaning some areas may see little to no snow.

Less than 10cm of snow is forecasted for the rest of Southern Ontario, with accumulations above 5cm confined to regions east of Lake Huron and around Lake Simcoe. Durham region could approach 10cm of snow, depending on the inland reach of the Georgian Bay snow squall. Eastern Ontario and the Golden Horseshoe are expected to see less than 2cm of snow.

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In Northeastern Ontario, snow from a system will continue affecting the northern regions, including Timmins, Kapuskasing, and Cochrane, with 20 to 30cm of snow possible.

Lake effect snow will be more localized, with Sault Ste. Marie anticipated to receive 15 to 30cm of snow before the squalls taper off late Thursday. The rest of Northeastern Ontario can expect widespread totals of 5-15cm, with some areas seeing up to 20cm.

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February 17, 2024

Snow Squalls Could Dump Up to 20-40cm of Snow on Parts of Ontario’s Snowbelt This Weekend

February 17, 2024/ Brennen Perry

Southern Ontario is starting to feel and look a lot more like winter after a mild beginning to February, which led to the melting of the existing snowpack in many areas. Thanks to a recent system that brought our first widespread snowfall in several weeks, we've seen the return of a snowy landscape.

This system also brought in colder air, kicking the lake effect snow machine back into gear across the typical snowbelt regions in Southern and Northern Ontario.

It's quite unusual to be discussing lake effect snow into February, as the lakes are usually mostly frozen over, reducing the source for snow squalls. However, due to the abnormally mild winter we've had, the lakes remain wide open with very little ice coverage.

As a result, snow squalls are expected throughout the weekend, especially east of Lake Huron, Lake Superior, and Georgian Bay. Snowfall totals could be significant, ranging from 15-30cm, with the potential for up to 40-50cm in the hardest-hit regions by the end of Sunday.

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Lake Huron and the southeastern shoreline of Georgian Bay have already been affected by lake effect snow for much of Friday, including areas like Kincardine, Port Elgin, Owen Sound, Collingwood, Wasaga Beach, and Barrie. Although the activity has lessened somewhat heading into the overnight hours and Saturday morning, it is expected to reorganize by the pre-dawn hours.

By Saturday morning, two main areas of heavy snow are expected: the first coming onshore around Port Elgin and affecting the southern portions of both Bruce and Grey counties, potentially extending into the northern sections of Huron and Perth counties.

Organized lake effect snow activity along the southern shorelines of Georgian Bay, including Collingwood and Wasaga Beach, may also bring heavy snow into the Barrie and Angus area at times throughout the morning.

A brief pause in the lake effect activity is anticipated as winds shift around by late Saturday morning, leading to a mostly snow-free afternoon, although some flurries may still linger near the lakes. As evening approaches on Saturday, a strong southwesterly flow will lead to the return of snow squalls off the lakes.

This time, the focus will shift to regions northeast of the lakes, placing the Muskoka and Parry Sound regions in the bullseye for the heaviest snowfall. Brief lake effect activity off Lake Erie and Lake Ontario could also bring a few hours of heavy snow to the southern parts of the Niagara region and extend into the Picton and Kingston regions.

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Lake effect snow will persist throughout the overnight and into Sunday. The bands are expected to fluctuate between a southwesterly to westerly flow during Sunday, affecting a larger area from Southern Muskoka northward into Parry Sound and Sundridge. Lake effect snow off Lake Huron is also expected during this time, with the Bruce Peninsula, Owen Sound, Kincardine, and Hanover regions seeing the heaviest snow.

Winds will shift again by Sunday afternoon, causing the remaining snow squalls to move southward and gradually weaken. There is some indication that these squalls could still be quite intense as they sweep across the Golden Horseshoe late Sunday afternoon or early evening, potentially bringing a quick burst of snow to the Greater Toronto Area and significantly reducing visibility. If you plan to travel during this time, be prepared for possible sudden whiteouts.

This will mark the end of the weekend snow squall activity. However, lake effect snow may return next week, but it's too early to discuss the exact impacts.

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Snow Squall Accumulation Disclaimer

Forecasting the exact snowfall accumulation for a specific location in a lake-effect snow event is extremely challenging. This is because of the highly localized nature of snow bands, which can lead to significant variance in totals even over short distances.
Therefore, you may notice our forecast shows significantly more snow than your weather app (including our own app). App-based forecasts often struggle with lake effect snow events due to their localized nature and reliance on data focused on larger macro-level weather events. This results in a failure to accurately capture the squalls, which operate at a micro-level, leading to intense snowfall totals.
Our forecast may still be off if the wind direction varies slightly from what the models predict, causing the snow squall band to form further north or south. That's why our forecasts use broader zones to account for this variability, meaning not everyone within these zones will see the significant totals. Essentially, we're indicating that a location within this area could see the forecasted amount.

Current data suggest the heaviest snowfall accumulation will focus on two zones: one encompassing the Port Elgin, Chatsworth, and Hanover region, and another east of Georgian Bay, including Parry Sound and much of Northern Muskoka. These areas could see around 20-40cm of snow over the next two days, with local amounts possibly exceeding 40cm and approaching 50cm.

Surrounding areas, including the Bruce Peninsula, Owen Sound, Meaford, Wingham, Kincardine, Bracebridge, and Sundridge, can expect between 15 to 30cm, with local amounts exceeding 30cm.

As is typical with lake-driven events, snowfall totals will decrease rapidly outside of the hardest-hit regions. Locations including Goderich, Shelburne, Collingwood, Wasaga Beach, Midland, Gravenhurst, Minden, and Algonquin Park could see 10-20cm of snow. Some of these regions may receive very little snow, depending on the positioning of the bands.

The 5-15cm zone extends not only around the Lake Huron and Georgian Bay snowbelt areas, including Fergus, Angus, Barrie, and Orillia but also covers the southern tip of the Niagara region and the Kingston area. This is due to brief snow squall activity expected off Lake Erie and Lake Ontario on Sunday morning.

For the rest of Southern Ontario, less than 5cm of snow is anticipated, although locally higher amounts could occur due to the snow squalls passing through late Sunday.

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Regions east of Lake Superior are also expected to see persistent snow squall activity starting Saturday afternoon and continuing throughout Sunday, concluding by Sunday afternoon as the lake effect activity shifts south.

The most significant accumulation is expected along the shorelines of Lake Superior, with 20 to 40cm forecasted for the Wawa area extending southward to north of Sault Ste. Marie.

Further from Lake Superior, lower amounts are anticipated, although most of Northeastern Ontario should receive at least 5cm of snow as a weak system moves through early Sunday morning, enhanced by the lake.

February 14, 2024

Potential Snowstorm on the Horizon for Southern Ontario; Up to 20–30cm of Snow Possible on Thursday

February 14, 2024/ Brennen Perry

FORECAST UPDATE - FEB. 15 @ 10:55 AM

After reviewing the latest data, we've made several adjustments to our final forecast map for the snowfall set to begin later this morning and extend into the afternoon.

The worst conditions are expected during the afternoon hours with strong wind gusts leading to blowing snow and reduced visibility on the roads. Conditions will improve by the end of the day for most areas, but snow squalls will develop off Lake Huron and Georgian Bay later tonight.

The primary update is that we now anticipate the higher snowfall totals, exceeding 15cm, to be more localized to Central Ontario and the Grey-Bruce region. This is where lake effect snow is expected to enhance snowfall rates. Consequently, we've adjusted the forecast range from 15-25cm down to 15-20cm, as the higher end of the range no longer seems supported by current data. While some areas may still experience local amounts up to 25cm, such occurrences will be relatively isolated.

Areas including Port Elgin, Hanover, and Chatsworth are predicted to see around 20-30cm, combining system snow on Thursday with snow squall activity beginning late Thursday night into Friday. This zone has been narrowed as models provide greater clarity on the specific areas likely to be impacted by snow squall activity.

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For locations such as Kitchener, Guelph, Barrie, Peterborough, Smiths Falls, and Ottawa, snowfall totals are projected to be around 10-15cm. In the stretch from the Greater Toronto Area through to Kingston and into Extreme Eastern Ontario, we are forecasting 5 to 10cm of snow. Totals are expected to lean towards the 10cm mark further from the Lake Ontario shoreline, with those in closer proximity likely receiving closer to 5cm.

In the south, anticipated snow amounts for London and Hamilton have been revised downwards from 5-10cm to 2-5cm. Along the Lake Erie shoreline and into Deep Southwestern Ontario, minimal accumulation is expected due to a mix with rain.

earlier forecast

The snow drought that has held Southern Ontario in its grip for most of February is about to come to an end this Thursday with the arrival of an intense snowmaker. This system is on track to deliver widespread snowfall, with totals ranging from 10 to 25cm, and in some areas, as much as 30cm, thanks to lake effect snow east of Lake Huron.

Accompanying the heavy snow, strong wind gusts of 40-60 km/h are anticipated throughout Thursday. These conditions are likely to cause blowing snow and poor driving visibility, significantly impacting the evening commute across the Golden Horseshoe as well as Central and Eastern Ontario.

The lake effect snow is expected to persist into the weekend, affecting the usual snowbelt areas around Lake Huron and Georgian Bay. It's possible that localized snowfall amounts (including Thursday’s storm) could reach up to 50cm by week's end, particularly in Grey and Bruce counties where lake effect snow is forecasted to be most intense.

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The system will approach from the west during late Thursday morning, initially impacting areas around Lake Huron before spreading eastward through the afternoon. Deep Southwestern Ontario, including Windsor, Chatham, and the Lake Erie shoreline, might start the day with mixed precipitation, including freezing rain, before transitioning to rain as temperatures rise.

By the afternoon, heavy snow will extend across Central Ontario and into the Golden Horseshoe. There remains some uncertainty regarding the extent of mixed precipitation to the north. Consequently, areas closer to the shoreline, such as Hamilton, Burlington, Brampton, and Toronto, may see some mixed precipitation which would reduce the snowfall totals here.

Central and Eastern Ontario will continue to experience snowfall into Thursday evening. The most challenging conditions are expected during the late afternoon and early evening when both wind and snowfall rates will be at the strongest.

The system is anticipated to gradually exit the province shortly after midnight. However, lake effect snow may develop off Lake Huron and Georgian Bay, with a particularly strong squall likely between Owen Sound and Kincardine overnight. Although expected to weaken by Friday morning, lake-effect snow may still linger throughout the day, especially in Huron, Wellington, Grey, and Bruce counties.

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A zone with 20-30cm of snow has been added to the map to cover much of Grey and Bruce counties, including Port Elgin, Hanover, Chatsworth, and Owen Sound, to account for additional lake effect snow following the main system. Localized totals could surpass 30cm, depending on the intensity of the snow squall.

Given the latest data, we have increased confidence to adjust some areas from the 10-20cm zone to the 15-25cm zone, as this system appears to carry more moisture than initially expected. This adjustment affects much of Central Ontario and parts of Eastern Ontario.

Areas like Goderich, Kitchener, the northern Greater Toronto Area, Kingston, and the Ottawa Valley are expected to receive 10 to 15cm of snow as indicated by our earlier forecast. The exact totals here are more uncertain, and isolated pockets may exceed 15cm, depending on moisture distribution.

Near the Lake Ontario shoreline, lower snowfall totals are expected due to potential mixing and temperatures near the freezing mark. Cities such as Toronto, Mississauga, Oakville, Burlington, Hamilton, Woodstock, and London are projected to see 5-10cm of snow, though some locations, especially along the lakeshore, might not reach the 5cm mark.

The Niagara region and Deep Southwestern Ontario, including Sarnia, Chatham, and Windsor, are forecasted to see less than 5cm of snow. While significant snow accumulation isn't expected in these areas, freezing rain could pose a concern during late Thursday morning and early afternoon.

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This system will also impact southern parts of Northeastern Ontario, with Elliot Lake, Sudbury, and North Bay set to receive 15 to 25cm of snow. The rest of Northeastern Ontario, including Sault Ste. Marie, Chapleau, Timmins, and Cochrane, can anticipate 5 to 15cm. Northwestern Ontario, including Thunder Bay, is expected to see less than 5cm of snow.

February 13, 2024

Say It Ain’t Snow! Winter Returns to Southern Ontario With Up to 10-20cm of Snow on Thursday

February 13, 2024/ Brennen Perry

February has begun somewhat quietly in terms of active weather across Southern Ontario. The most significant event this month was the record-breaking warmth experienced late last week, with temperatures soaring well into the double digits throughout much of our region. Following Wiarton Willie's bold prediction of an early spring on Groundhog Day, it momentarily seemed as though the famed groundhog was on to something.

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However, the brief taste of spring was merely an illusion, as more typical seasonal temperatures have since made a comeback. We are now tracking a system that poses the first risk of widespread snowfall for the month. Expected to start early Thursday and continue into Friday, this quick-moving system could bring snowfall totals of 10 to 20cm across much of Central and Eastern Ontario.

This weather system is forecasted to move in from the west during the morning hours on Thursday, beginning with areas around Lake Huron and spreading eastward throughout the afternoon. In Deep Southwestern Ontario, including Windsor, Chatham, and along the Lake Erie shoreline, the day could start with mixed precipitation, including freezing rain, before transitioning to regular rain as warmer air prevails.

There's some uncertainty regarding how far north this mixed precipitation will extend. It could result in lower snowfall totals from London through Hamilton and into parts of the Greater Toronto Area, especially near the shoreline.

Central and Eastern Ontario are set to experience moderate to heavy snow, likely impacting the evening commute on Thursday. As this is a fast-moving system, the majority of the snow is expected to fall within a 6-12 hour period during Thursday afternoon and evening.

The snow should begin to taper off just before midnight. However, lingering flurries and light snow may continue to affect Eastern Ontario into the early hours of Friday, with the system expected to exit Southern Ontario by sunrise on Friday.

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Due to the dynamic nature of this system, pinpointing exact snowfall totals for each area is challenging, as the moisture content will vary. Currently, a broad swath of Southern Ontario, from the Lake Huron shoreline through Central Ontario and into Eastern Ontario, is projected to receive 10 to 20cm of snow.

It's important to note that the higher end of the 20cm forecast is reserved for isolated areas that may experience lake enhancement, leading to locally heavier snowfall. More commonly, amounts are likely to be closer to 10cm, though some areas may see higher totals.

Snowfall totals are expected to decrease further south, with around 5 to 10cm anticipated for the London, Hamilton, and Toronto regions. This lower accumulation is attributed to the potential for mixed precipitation and lower snowfall ratios.

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The Windsor, Chatham, Sarnia, and Niagara regions are forecasted to receive less than 5cm of snow due to even greater mixing and limited opportunities for snow accumulation.

This system is also expected to impact the southern part of Northern Ontario, with Elliot Lake, Sudbury, and North Bay poised to see 10 to 20cm of snow. The rest of Northeastern Ontario, including Sault Ste. Marie, Chapleau, Timmins, and Cochrane, can expect around 5 to 10cm. Northwestern Ontario, including Thunder Bay, is forecasted to receive less than 5cm of snow.

January 19, 2024

Snow Squalls Return to Southern Ontario’s Snowbelt This Weekend With Up to 25-50cm Possible

January 19, 2024/ Brennen Perry

While the lake effect machine has settled down somewhat after intense squalls buried some areas under more than 100cm of snow this week, the threat of snow squalls is expected to return starting late Friday afternoon.

A weak system that tracked just south of the Great Lakes brought flurries and light snow to areas around Lake Erie earlier on Friday. As this system moves away, another surge of cold Arctic air is set to sweep across Southern Ontario later in the day.

With winds aligning in a predominantly north-to-northwesterly direction starting this afternoon, snow squalls are anticipated to redevelop off Lake Huron and Georgian Bay.

However, the focus of this lake effect snow will shift from earlier this week when the heaviest bands were east of Lake Huron and Georgian Bay. This time, regions to the south and southwest of these lakes, including the Sarnia to London corridor and the Meaford and Collingwood area, will be most affected.

By Sunday, when the lake effect snow is expected to move out, local accumulations could reach upwards of 25cm in the hardest-hit regions. Depending on the squalls' intensity and whether they shift during the next 24-36 hours, some pockets may even see close to 40-50cm.

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We've already seen the snow squalls forming over Lake Huron as they initially reached into the Sarnia region and are now shifting eastward with the changing wind direction to more NNW.

By the dinner hour, these squalls should have settled around the Lambton Shores, Strathroy, and Grand Bend areas. This intense band is expected to stay mostly stationary through the evening and into the night.

As a result, travel between Sarnia and London will likely be hazardous starting this evening due to rapid snow accumulation and near-zero visibility.

This evening will also bring some disorganized lake-effect snow along the southern shoreline of Georgian Bay, affecting areas such as Owen Sound, Meaford, Flesherton, and Collingwood. The most intense snowfall rates are forecasted for the higher elevations southwest of Collingwood, including the Blue Mountains.

As Saturday morning arrives, the Lake Huron squall is projected to shift slightly eastward as the winds become more westerly, pushing the heaviest snow east of Grand Bend and towards the Lucan, St. Marys, and potentially London areas.

The Georgian Bay lake effect snow is also expected to push eastward into the Angus, Wasaga Beach, and Shelburne areas.

These regions will continue to experience lake-effect snow throughout Saturday and into Sunday. However, models suggest that the intensity of the bands should gradually wane by late Saturday, which would help limit total accumulations.

By Sunday morning, we anticipate the lake effect snow will diminish as winds shift to a less favourable direction for squalls.

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Forecasting the exact snowfall accumulation for a specific location in a lake-effect snow event is extremely challenging. This is because of the highly localized nature of snow bands, which can lead to significant variance in totals even over short distances.

Therefore, you may notice our forecast shows significantly more snow than your weather app (including our own app). App-based forecasts often struggle with lake effect snow events due to their localized nature and reliance on data focused on larger macro-level weather events. This results in a failure to accurately capture the squalls, which operate at a micro-level, leading to intense snowfall totals.

Our forecast may still be off if the wind direction varies slightly from what the models predict, causing the snow squall band to form further north or south. That's why our forecasts use broader zones to account for this variability, meaning not everyone within these zones will see the significant totals. Essentially, we're indicating that a location within this area could see the forecasted amount.

Current predictions indicate the highest snowfall totals from this event will be found between Lambton Shores and Grand Bend. Models are not in complete agreement on where this narrow band will establish itself and persist over a specific area. Somewhere in this region has the potential to see anywhere from 25 to 50cm, with over 50cm not being out of the question.

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The snowfall gradient is quite steep, meaning totals will decrease rapidly outside this core zone. Strathroy could see approximately 15-30cm, while Lucan may receive about 10-20cm. Yet again, locally higher amounts cannot be ruled out.

The City of London's forecast is somewhat uncertain, depending on the inland reach of the snow squall on Saturday. It could remain closer to the shoreline, resulting in about 5cm of snow for the city, or it could extend further inland, bringing potentially 10-15cm or more, especially to the northern and northwestern parts of London.

Approximately 5-15cm of snow is expected along the rest of the Lake Huron shoreline, including Kincardine, Goderich, and south through St. Thomas. Areas in Southwestern Ontario, such as Sarnia and Chatham, should see less than 5cm.

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The snowfall totals south of Georgian Bay are expected to be less than those from Lake Huron, due to the lake effect snow being more disorganized. Nevertheless, we could see 15-30cm of snow in the higher elevations, such as the Blue Mountains south of Collingwood and Meaford.

Near the shoreline, the Collingwood area can expect around 10 to 20cm of snow. Further inland, including Owen Sound, Chatsworth, Flesherton, Angus, and Wasaga Beach, accumulations of 5 to 15cm are possible.

The City of Barrie is not likely to see much from this round of lake effect snow, with an expected 2-5cm. The rest of Southern Ontario can anticipate sporadic lake effect flurries throughout the weekend, which may total a few centimetres.

Rapid whiteout conditions on the roads are still possible, so even if significant accumulations aren't expected, it's important to drive according to the conditions.

January 16, 2024

Relentless Snow Squalls to Bury Parts of Ontario’s Snowbelt in Up to a METRE (100cm) of Snow by Wednesday

January 16, 2024/ Brennen Perry

The coldest air of the season has settled across Southern Ontario, fueling the lake effect machine that has battered parts of the snowbelt over the weekend. Intense squalls have led to significant snowfall, with reports of over 40-50cm in the Orillia and Owen Sound region.

Though these areas saw a respite in squall activity as the bands shifted north last night, the focus now turns to a different part of the snowbelt for the next few days. A strong southwesterly flow over the Great Lakes is expected to continue through Tuesday and into Wednesday leading to continuous snow squall activity.

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Heavy bands of snow is expected to settle over areas such as Tobermory, Parry Sound, Britt, and Sundridge, potentially burying them in up to 100cm, or 1 meter, of snow in the coming days. A similar situation is unfolding further north, with intense squalls east of Lake Superior, particularly impacting the Wawa area.

Lake Erie and Lake Ontario are also set to bring significant snow to the Southern Niagara Region and Prince Edward County, as squalls spill north of the border, especially by Wednesday morning. This could result in several hours of lake effect snow hammering the Fort Erie and Port Colborne region.

Off Georgian Bay, snow squalls are stretching across the Bruce Peninsula and coming ashore between Parry Sound and Britt. Minor lake-effect snow from Lake Erie and Lake Ontario is expected to continue overnight into Tuesday morning.

A weak system sliding mostly south of the border could be enhanced by the lakes, leading to heavier snow around the Niagara Region and Eastern Ontario, particularly near Kingston. For the rest of Southern Ontario, expect light snow or flurries throughout the morning, leading to a few centimetres of accumulation at most.

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On Tuesday, the situation for those northeast of Georgian Bay remains unchanged, with intense squalls continuing around Parry Sound, stretching into Sundridge and North Bay. However, by late evening, the southern band may shift to a westerly direction, focusing on the Rosseau and Huntsville area and continuing into Wednesday morning, bringing extreme snowfall totals to northern Muskoka and the Parry Sound region.

For the Niagara region, the Lake Erie squall will remain south of the border for most of Tuesday but is expected to drift north by Wednesday morning. This could significantly impact the Fort Erie and Port Colborne areas with rapid snowfall accumulation and near-zero visibility. Prince Edward County may also experience intense squalls drifting as far north as Belleville and Kingston throughout Wednesday.

Later on Wednesday, intense squalls off Georgian Bay may shift southward into the Port Carling, Bracebridge, and Orillia area. There is some uncertainty regarding the squall's location overnight, but it is expected to continue into Thursday. A separate forecast for the rest of the week will be issued soon.

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By late Wednesday, we could be talking about extreme snowfall totals in a zone including Rosseau, Parry Sound, Sprucedale, Burk’s Falls, and Sundridge, with 40 to 80cm of snow expected over the next two days. Local totals could reach triple digits, with 100cm not out of the question if an intense band persists over a particular location.

The Bruce Peninsula and northern Muskoka, including Huntsville, Port Sydney, and North Bay, can expect around 25 to 50cm of snow, although some areas might see less, depending on squall locations. The rest of Muskoka and Algonquin Park are looking at 10-30cm of snow. Central Ontario should see less than 10cm as squalls focus northeast of Georgian Bay.

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In the southern Niagara region, including Fort Erie and Port Colborne, snowfall totals could range from 25 to 50cm by Wednesday's end, with most snow coming on Wednesday. Prince Edward County, including Picton, may also see over 25cm of snow in the next few days.

East of Lake Huron, heavier snow is expected in higher elevations away from the shoreline. This includes Owen Sound, Hanover, and Wingham, where between 15-30cm of snow is anticipated, mostly arriving later on Wednesday as more organized lake effect activity begins. Along the shoreline, places like Kincardine and Goderich are forecasted to see less than 10cm of snow.

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In Northeastern Ontario, relentless snow squall activity is likely between the Sault Ste. Marie and Wawa corridor, with snowfall totals ranging from 40-80cm. Some spots could far exceed 80cm, particularly just south of Wawa where the squalls will be most intense. Snowfall totals will quickly decrease further away from Lake Superior.

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January 13, 2024

Multi-Day Snow Squall Event Could Dump Up to 50cm of Snow on Parts of Ontario’s Snowbelt by Monday

January 13, 2024/ Brennen Perry

After the widespread snowstorm brought blizzard conditions and even thundersnow on Friday, attention now shifts to a potential multi-day snow squall event in parts of Ontario. This event is set to start on Saturday evening and continue through Monday.

These squalls could potentially dump over 50cm of snow locally in the typical snowbelt regions around Lake Huron, Georgian Bay, and Lake Superior in the coming days. Notable accumulations are also likely through the Fort Erie and Picton area as squalls from Lake Erie and Lake Ontario occasionally cross the border throughout Sunday.

In addition to the expected significant snowfall, these squalls pose a threat of near-zero visibility, creating dangerous driving conditions in the affected areas. It's advisable to avoid the roads until conditions improve, as the lake effect snow may lead to road closures.

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Snow squall activity has started off Lake Huron and Georgian Bay as of late Saturday evening. Currently, the lake effect snow is somewhat disorganized, with a thin squall stretching across the Bruce Peninsula into the Muskoka region east of Georgian Bay. Some lake effect activity is also happening south around the Kincardine and Goderich regions.

These squalls are expected to intensify overnight, with colder temperatures leading to more efficient snow accumulation. The worst conditions are anticipated in the entire Grey and Bruce counties east of Lake Huron, extending southward into Huron and Perth counties.

Over Georgian Bay, the area between Bracebridge/Port Carling and south to Orillia/Midland will be the focus. There's a chance a strong squall will establish here, though it's uncertain if it will remain stationary or drift around. If it moves, the snowfall will spread over a larger area, as opposed to localized pockets if it remains stationary.

Early Sunday morning, the Lake Erie squall, currently affecting the Buffalo region, is expected to briefly move north of the border. This will bring heavy snow for a few hours to parts of the Niagara region. The most intense snowfall rates are expected near the Lake Erie shoreline, including Port Colborne and Fort Erie.

Similarly, late Sunday morning, the Lake Ontario band is forecasted to stretch across Prince Edward County to Kingston and possibly as far north as Brockville. While only about 5-10cm of snow is expected, it will occur rapidly, accompanied by whiteout conditions. Such events often lead to crashes on the Hwy 401 corridor between Belleville and Brockville, so extreme caution is advised if travel is necessary during this time.

Both Lake Ontario and Lake Erie squalls will move back south by early afternoon as the wind direction shifts. However, the Lake Huron and Georgian Bay squall will continue to heavily impact Muskoka, Simcoe County, Kawartha Lakes, Grey County, Bruce County, Huron County, and Perth County throughout the afternoon.

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Some models suggest the Lake Huron squall could stretch far inland at times with a more northwesterly flow, potentially bringing brief heavy snow to the Greater Toronto Area, Kitchener, and Guelph. Sudden reductions in visibility are possible if one of these squalls moves into your area. Areas east of Georgian Bay, including Muskoka and Parry Sound, might get a break from the snow during the afternoon as the intense bands move southward.

By evening, the wind direction is expected to shift back to a westerly direction, leading to the return of squalls in the Muskoka and Northern Simcoe County regions, as well as the Owen Sound, Kincardine, and Wiarton areas for the Lake Huron squall. Additionally, the squalls may return to the Niagara and Picton/Kingston regions after midnight, leading to more heavy snow into early Monday morning.

Our forecast only extends to Monday afternoon due to lower confidence in the exact direction of the squalls beyond that point. However, the risk will certainly continue through Monday and into Tuesday.

Current indications suggest a more southwesterly direction throughout Monday, putting the Parry Sound, Sundridge, and North Bay regions in the path of the intense squall.

The snow squall off Lake Ontario and Erie could remain stationary for many hours through the Niagara region and Kingston area, leading to potentially significant snowfall totals. More details on this will be provided in a separate forecast.

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The hardest-hit regions for the Lake Huron squall are expected to be most of Grey and Bruce counties, including Port Elgin, Hanover, Chatsworth, Owen Sound, and Wiarton. Snowfall totals here by Monday afternoon will generally range from 25 to 50cm, with some localized areas possibly exceeding this mark depending on the intensity of the squall activity.

For those east of Georgian Bay, the highest snowfall totals are likely in Southern Muskoka and Northern Simcoe County. Again, snowfall totals in locations such as Midland, Washago, Gravenhurst, Bracebridge, and Port Carling will range from 25 to 50cm, with some areas potentially exceeding 50cm.

The accumulation will quickly decrease away from the main regions, as this event is very localized. Around 15 to 30cm of snow is expected for places like Parry Sound, Haliburton, Orillia, Collingwood, Shelburne, Huron County, and Perth County. Further out, locations such as Kawartha Lakes, Wasaga Beach, Fergus, and Goderich could see 10 to 25cm of snow.

Less than 15cm is possible for the surrounding areas, with most places seeing less than 5cm. However, some areas could receive more if they encounter a brief snow squall. This includes Barrie, Kitchener, Guelph, the Greater Toronto Area, and Peterborough.

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In the Niagara region, the highest totals will be along the Lake Erie shoreline, including Fort Erie, Port Colborne, and Turkey Point, with up to 15-30cm possible. Most of this snow will fall early Sunday morning and later in the evening.

The forecasted totals will decrease rapidly the further away from Lake Erie you are. Welland could see around 10-20cm, while Niagara Falls might get 5-10cm. St. Catharines is expected to be less affected, with maybe 5cm of snow possible.

In Eastern Ontario, Picton, Napanee, and Kingston will see the most snow from Lake Ontario. The hardest-hit areas are currently projected to receive around 10-15cm, although the southernmost tip of Prince Edward County could approach 20cm.

Along the International Border into Brockville, up to 5-10cm of snow is expected from the squall moving across the area late Sunday morning.

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Intense snow squalls are also ongoing south of Lake Superior and are expected to move north of the border during Sunday afternoon. This will result in rapid snow accumulation east of Lake Superior, somewhere between Wawa and Sault Ste. Marie.

Snow squall activity in this region is expected to continue into Monday and even Tuesday. By Monday afternoon, the hardest-hit areas, including Sault Ste. Marie, will see totals ranging from 25 to 50cm. Additional snowfall late Monday into Tuesday will add to these totals.

Further east, the Chapleau and Elliot Lake regions could also experience heavy lake effect snow, with around 10-20cm of accumulation possible. The rest of Northeastern Ontario should see around 5-15cm, with lower totals further away from the lake.

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January 11, 2024

Intense Blast of Snow on Friday Evening Could Bring Blizzard Conditions & Up to 20-30cm of Snow to Parts of Ontario

January 11, 2024/ Brennen Perry

Confidence remains high regarding a snowstorm set to impact Southern and Northeastern Ontario from late Friday into Saturday. Despite a slight reduction in the predicted snowfall totals, we're still on track for a high-impact event. This event will feature several hours of intense snowfall and strong wind gusts, which are likely to result in blizzard conditions and blowing snow.

Currently, we're anticipating a widespread snow accumulation of 15-30cm across Southern Ontario. However, areas closer to the Lake Ontario and Erie shorelines may see lower amounts, as a switch to rain is expected to limit the overall accumulation.

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There's a degree of uncertainty regarding the extent of warm air intrusion, leading to discrepancies in the snowfall totals projected by different models. To account for this variance, we've opted for broader snowfall ranges instead of predicting a definitive outcome of either warm or cold air dominance.

The likelihood of warmer air influencing the weather, followed by a rapid cooldown early Saturday, introduces the risk of a flash freeze. Areas along the Lake Erie and Ontario shorelines might experience slushy conditions late Friday night due to temperatures rising to the mid-single digits and mixing with rain. This slush is expected to freeze quickly as colder air moves in behind the system, potentially leading to icy road conditions on Saturday morning.

We expect the storm's initial band of snow to hit between 4-6 PM on Friday, starting in Extreme Southwestern Ontario. This band is poised to deliver a short, intense burst of heavy snowfall, with rates of 4-8cm per hour, possibly accompanied by thundersnow.

Accompanying strong wind gusts, which could reach up to 90km/h in some localities, are expected to create hazardous driving conditions, particularly in Southwestern Ontario, the Golden Horseshoe, and parts of Central Ontario, where localized blizzard conditions may occur.

This heavy snow will progress through Southwestern Ontario, impacting London, Kitchener, and Hamilton by early evening. It will reach the Greater Toronto Area later in the evening, and eventually spread northeast to Central and Eastern Ontario, continuing overnight into early Saturday.

While the most intense snowfall will be brief, moderate snow is expected to persist behind the initial band throughout the night into Saturday. Around the Lake Ontario and Erie shorelines, a surge of warmer air Friday night into Saturday morning could result in a temporary changeover to rain, especially affecting snowfall totals in the Niagara region and parts of the Greater Toronto Area near the lakeshore.

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There's increased confidence that warmer air will move in along the Lake Erie and Ontario shorelines after the intense snow band passes in the evening. This could lead to reduced snowfall totals in the Niagara region and parts of the Greater Toronto Area (GTA) near the lakeshore.

Higher-resolution models suggest that snowfall accumulation may vary significantly based on elevation. Therefore, areas like the Dundalk Highlands and along the Oak Ridges Moraine north of the GTA are likely to receive higher snowfall totals.

Steady snowfall is expected to persist throughout Southern Ontario on Saturday, with the most intense snow occurring in Eastern Ontario. The arrival of much colder air in the wake of the system will also trigger lake-effect snow squalls off Georgian Bay and Lake Huron.

These snow squall conditions are expected to continue into the next week, with the cold Arctic air remaining over our region. This could result in significant snowfall accumulations throughout the week in areas including Goderich, Kincardine, Hanover, Owen Sound, Wiarton, Barrie, Orillia, Midland, Bracebridge, Huntsville, Parry Sound, Britt, and Sundridge.

It's important to note that snowfall totals from this event will be highly variable, influenced by local factors that are difficult to precisely predict. Therefore, app-based forecasts, including ours, may vary from the forecast presented here. Our approach involves providing a broader range to account for various potential scenarios.

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We believe the hardest-hit regions will be parts of Eastern Ontario, specifically between Peterborough and Ottawa. The entrenched colder air in this area is expected to prevent any mixing, leading to significant snowfall.

The intense snow band on Friday could stall over Eastern Ontario for several hours, weakening gradually. Snowfall totals in this region are anticipated to range from 20 to 35cm, though localized areas could receive up to 40cm by the end of Saturday.

Central and Eastern Ontario, away from the Lake Ontario shoreline, are projected to receive about 15 to 25cm of snow. However, local accumulations could exceed 30cm, particularly in elevated regions through Orangeville, Shelburne, and York Region.

Areas around Georgian Bay, including Barrie, Orillia, and Muskoka, are expected to underperform in terms of snow accumulation. We're forecasting 10 to 20cm to account for this potential dry slot.

The forecast becomes more complex further southeast into the Golden Horseshoe. Away from the shorelines of Lake Erie and Ontario, snowfall totals are likely to exceed 10cm and could approach 20cm in some areas.

Closer to the shorelines, we anticipate accumulation ranging from 5 to 15cm. This broad range accounts for the uncertainty, with areas right along the shoreline likely seeing closer to 5cm, while a few kilometres inland could receive up to 15cm.

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The tight gradient makes it challenging to represent on a map, hence the larger range. This 5 to 15cm range also applies to much of Deep Southwestern Ontario, including Windsor and Sarnia, with most of the snowfall occurring within a few hours late Friday afternoon.

The Lake Erie shoreline into the Hamilton region is expected to receive less than 10cm of snow. Meanwhile, the Niagara region might see the least amount, with less than 5cm possible.

In Eastern Ontario, significant snowfall totals are expected to be widespread, with the 20-35cm zone southwest of Ottawa. The City of Ottawa itself is likely to see around 15 - 25cm, though totals approaching 30cm cannot be discounted.

Further southeast, the warm air will influence snowfall in the Kingston, Brockville, and Cornwall areas early Saturday morning, likely limiting totals to a general 10-20cm. However, areas right along the international border, including Cornwall and Brockville, might not even reach the 10cm mark.

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Northeastern Ontario is also set to be affected by this event, with over 20cm of snow forecasted starting late Friday evening. The heaviest band of snow is expected to move across Manitoulin Island and into the Sudbury region early Saturday morning, with snowfall rates of 3-6cm per hour.

Blowing snow and localized blizzard conditions are a concern during the morning hours across the southern portion of Northeastern Ontario, including Sudbury and North Bay. Moderate snowfall is expected to continue across Northeastern Ontario throughout Saturday, tapering off later in the evening.

The highest totals are forecasted from Manitoulin Island through Elliot Lake, Sudbury, and North Bay, with 20 to 35cm of snow possible. Locally, up to 40cm can't be ruled out, especially given the intensity of the morning snowfall.

Less snow is expected further northeast, with around 10-20cm for Sault Ste. Marie, Chapleau, and Timmins. Even lower amounts, ranging from 5 to 15cm, are possible from Wawa to Kapuskasing.

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January 10, 2024

Get Your Shovels, Southern Ontario! The First Major Snowstorm of the Season Is on the Way This Weekend

January 10, 2024/ Brennen Perry

Confidence is growing in a strong system set to sweep across Southern Ontario starting Friday and persisting throughout the weekend. In contrast to previous weather systems, this one looks likely to keep most of the region on the snowy side, leading to widespread and substantial snowfall.

Although there's always a chance for last-minute changes, it's nearly certain that parts of Southern Ontario are in for a heavy snowfall this weekend. The onset is expected sometime Friday afternoon, continuing into Saturday.

We're still finalizing the exact details, but a more detailed preliminary forecast will be available later today.

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Currently, we anticipate general snowfall totals in the range of 20-30cm across a broad area of Southern Ontario, extending from the Southwest through the Greater Toronto Area and into Central/Eastern Ontario.

Almost everyone in these regions should brace for significant snowfall. In some localities, particularly around Lake Huron and Georgian Bay, totals could surpass 30cm, boosted by lake-enhanced snowfall.

The combination of intense snow and potentially strong, damaging wind gusts of 70-90km/h could lead to complete whiteouts. We can't discount the possibility of blizzard conditions, especially in Southwestern Ontario.

The main area of uncertainty lies along the Lake Ontario shoreline and in the Niagara region. Some forecasts suggest a brief switch to rain overnight on Friday, followed by a return to snow on Saturday.

This could result in lower snowfall amounts near the shoreline, heavily dependent on the storm's exact path. The latest data shows a trend towards a westward path, which could introduce warmer air into the region.

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Another aspect we're watching closely is the potential for significant lake effect snow following the storm, starting Sunday and possibly extending into the week. This could lead to remarkable snowfall accumulations in typical snowbelt areas such as Grey-Bruce, Simcoe County, Muskoka, and Parry Sound.

By week's end, some of these areas might be measuring the snow in FEET (1 ft = 30cm).

In summary, the upcoming week promises to be a busy one, but we're prepared and will keep you updated with in-depth information around the clock. Stay tuned!

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January 08, 2024

Winter Storm Threatens Tuesday Evening Commute Across Ontario Including the GTA; Significant Snowfall to the North With Up to 35cm Possible

January 08, 2024/ Brennen Perry

The New Year in Ontario has been notably active, marked by several snowy systems over the past week. This trend is expected to continue with a significant winter storm approaching, bringing heavy snow, ice pellets, and some freezing rain beginning Tuesday morning.

We are also closely monitoring a potential high-impact storm this weekend, which may deliver a more substantial impact, focusing on heavy snow rather than mixed precipitation.

More details about the looming snowstorm threat will be provided in the coming days. For now, our attention is on the imminent winter storm, which presents a complex forecast involving various winter weather threats. Weather models have struggled to determine the exact path of this system, but there is broad agreement as we approach 24 hours before the system's arrival.

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The heaviest snowfall is expected to occur primarily in Northeastern Ontario, extending southward into Central and Eastern Ontario. In these areas, precipitation is likely to remain frozen for most of the event, resulting in higher snowfall totals. By early Wednesday, the hardest-hit areas could see over 20cm of snow, with some locales receiving more than 30cm.

In the rest of Southern Ontario, the scenario is more complex. We anticipate wet snow in most regions on Tuesday morning, transitioning to rain as temperatures rise, beginning in Deep Southwestern Ontario and around the Lake Huron shoreline.

The speed of the warmer air's advance northward creates uncertainty regarding overall snowfall accumulation. Strong wind gusts accompanying the icy mix may reduce visibility and cause blowing snow.

By Tuesday afternoon and evening, a large portion of Southwestern Ontario and the Golden Horseshoe is expected to shift to ice pellets and then rain. This transition may coincide with peak evening rush hour, potentially leading to hazardous travel conditions. We advise preparing for extended travel times or considering staying off the roads until conditions improve.

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To clarify the timeline of the various precipitation shifts, we will detail the expected impact of this winter storm for each part of Tuesday and Wednesday.

Focusing on the timeline rather than the amounts is crucial, as accumulating snow at the storm's onset will likely be washed away by rain, making accurate measurement challenging. The rapid shifts in precipitation types, leading to icy and slushy road conditions, are the main threat of this winter storm.

The storm will begin early Tuesday morning as initial bands of precipitation cross into Deep Southwestern Ontario. Heavy wet snow is expected in Windsor, Chatham, Sarnia, London, and the Niagara region, transitioning to rain by late morning.

Further north, colder air will result in more prolonged snow across the Golden Horseshoe and westward through the Kitchener region. Ice pellets may mix in, especially along the Lake Ontario shoreline and south of the Hwy 401 corridor.

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As the afternoon progresses, the storm will intensify across Southern Ontario. Areas in Deep Southwestern Ontario and along the Lake Erie shoreline into the Niagara region will have switched to rain, minimizing the impact.

There is uncertainty in the Lake Huron shoreline and the Greater Toronto Area, where precipitation types will vary due to slight temperature differences.

Areas closest to the shoreline, including Hamilton, Burlington, Mississauga, and Toronto, will see a mix of ice pellets and snow during the early afternoon. However, by late afternoon, some rain is expected to mix in.

Regions north of the Hwy 401 corridor are likely to experience continued heavy snow mixed with ice pellets at times. Combined with strong wind gusts of 60-80km/h, travel could be difficult due to blowing snow and ice pellets.

A slight risk of brief freezing rain exists in this area, although sustained freezing rain is unlikely. The more likely progression will be from snow to ice pellets to rain.

Heavy snow will also affect Central Ontario around Lake Simcoe and eastward along the Lake Ontario shoreline into Eastern Ontario. Expect several hours of heavy snow throughout the afternoon.

Those in the Quebec border area and the Ottawa Valley will see the first snow bands by late afternoon, starting with lighter snow and intensifying later.

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By evening, warmer air will begin to replace the cold air, leading to a wider transition from frozen precipitation to rain. Southwestern Ontario and the Golden Horseshoe will have mostly switched to rain.

In southern parts of Central and Eastern Ontario, snow will persist into the early evening, potentially mixing with rain near midnight.

Heavy snow will continue for the Quebec border and Ottawa Valley regions throughout the evening. Ice pellets may mix in, extending from north of Parry Sound through Huntsville to the Smiths Falls and Cornwall areas.

Northeastern Ontario is expected to see persistent heavy snow from late Tuesday afternoon through the night. Little mixing is anticipated in this area.

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The storm will persist into early Wednesday, primarily affecting northern parts of Central and Eastern Ontario. South of a line from Bracebridge to Smiths Falls is expected to switch to rain by midnight.

Heavy snow will continue in the Ottawa Valley and Northeastern Ontario. By mid-morning, some mixing, including ice pellets and potentially freezing rain, is expected.

By sunrise, most of Southern Ontario will have switched to rain, while snow continues in Northeastern Ontario. The Ottawa region may not experience this transition if warmer temperatures fail to displace the cold air. Wednesday morning's commute in Eastern Ontario, especially the Ottawa Valley, is likely to be challenging.

As the system leaves the region, temperatures are expected to drop below freezing by early Wednesday morning in Southwestern Ontario and late morning or early afternoon in the rest of Southern Ontario. This will result in a transition back to wet flurries later on Wednesday, although significant accumulation is unlikely.

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While the variety of precipitation types is a key story of this storm, overall snowfall accumulation in some areas will resemble a classic snowstorm rather than a messy winter storm.

Starting with the least affected region, Deep Southwestern Ontario and the Niagara region are expected to see less than 5cm of snowfall, primarily on Tuesday morning before being washed away by rain.

Snowfall totals along the Hwy 401 corridor from London through Hamilton to the GTA are expected to be around 5 to 10cm early on Tuesday before switching to rain. This forecast is tricky, as slight temperature variations can significantly affect snowfall amounts. Thus, focus less on specific amounts in this region.

Areas north of the Hwy 401 corridor and away from the Lake Ontario shoreline are likely to see prolonged heavy snow throughout Tuesday morning and afternoon. Snowfall totals could reach 10-15cm in some areas, especially in higher elevations around the Dundalk Highlands, Kitchener, and Guelph regions, where some models suggest localized totals may exceed 15cm.

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This zone, encompassing much of southern Central and Eastern Ontario, has more variance, leading to a wider range of 5cm to 15cm in snowfall totals. This forecast acknowledges the uncertainty in this area, providing a complete picture rather than a definitive prediction.

Further north, snowfall totals of 10 to 20cm are expected from Parry Sound through Muskoka to the Tweed and Cornwall areas.

Even higher totals are anticipated in northern Central Ontario, including Sundridge, Bancroft, and the Ottawa Valley, with a general range of 15-25cm possible. Localized pockets may even see up to 30cm.

The Algonquin Park, Renfrew, and Pembroke areas are forecasted to be the worst hit in Southern Ontario, with expected snowfall between 20 to 35cm.

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In addition to snowfall, significant rain and wind are associated with this system, particularly in the south. Rainfall totals will range from 30 to 50mm across Deep Southwestern Ontario, along the Lake Erie shoreline, and into parts of Eastern Ontario north of Lake Ontario.

Rainfall totals will decrease further north, with around 20 to 30mm expected along the Lake Huron shoreline and into the GTA near Lake Ontario. For southern parts of Central and Eastern Ontario, rainfall totals between 10 to 20mm are expected, but actual precipitation will be higher when melted snow is considered, raising flooding concerns.

Less than 10mm of rain is anticipated for more northern parts of Central and Eastern Ontario, as they are likely to remain predominantly on the cold side of the storm.

Strong to damaging wind gusts are also a risk during Tuesday afternoon and evening. While there is some disagreement on the intensity, some models suggest gusts could approach 90-100km/h around the Lake Erie shoreline, Niagara region, and Prince Edward County.

For the rest of Southwestern Ontario into the Golden Horseshoe, wind gusts will range from 50 to 70 km/h, with a slight chance of 70-85 km/h gusts if the more intense model proves accurate.

For Northeastern Ontario, the event will primarily be a snowstorm, starting Tuesday afternoon and continuing into Wednesday afternoon.

Snowfall totals are expected to be significant, with the hardest-hit regions from Manitoulin Island through Sudbury, North Bay, and into the Kirkland Lake region anticipating 20 to 35cm, with some areas possibly reaching 40cm.

Lower amounts are forecasted further west, with 15 to 25cm expected in areas including Elliot Lake, Timmins, and Cochrane.

Closer to Lake Superior, including Sault Ste. Marie, Wawa, and Kapuskasing, around 10 to 15cm of snow is expected, although this may vary by location. For a more detailed forecast, refer to the accompanying map.

In summary, this winter storm brings a mix of precipitation types across Ontario, with varying impacts depending on the region. The forecast includes heavy snow, rain, and strong winds, with significant snowfall in certain areas. Residents should stay informed and prepare for potentially hazardous travel conditions.

January 05, 2024

Parade of Snowstorms Take Aim at Ontario Over the Next Week Beginning With Up to 15-20cm of Snow This Weekend

January 05, 2024/ Brennen Perry

Winter in 2023 started sluggishly, but as the New Year unfolds, Ontario is witnessing a dramatic shift in weather patterns. The mild conditions that prevailed in late December have been replaced by colder air.

This transition is not just a mere drop in temperatures; it's also bringing a series of snowy systems. Over the coming week, these systems are poised to bring considerable snowfall to various regions across the province.

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The first significant snowfall is expected over the weekend, thanks to two distinct weather systems. In the north, a system originating from the US Midwest will traverse Northern Ontario starting Saturday morning.

This will result in continuous snowfall across both Northwestern and Northeastern Ontario throughout the day. By Sunday morning, snow accumulations could reach 15-20cm in some areas.

Simultaneously, a robust system from the US East Coast is anticipated to make its way northward. The northwestern fringes of this system are expected to cross into Canada by late Saturday afternoon. However, there remains some uncertainty regarding its exact path, particularly as it interacts with the northern precipitation.

This uncertainty may affect the total snowfall, but the highest accumulations are likely in Extreme Eastern Ontario, along the St. Lawrence River. Some regions here might witness up to 15cm or more of fresh snow by the weekend's end. Additionally, lake enhancement along the western shores of Lake Ontario could result in up to 10cm of snowfall in parts of the Golden Horseshoe area.

Yet, this is merely the beginning. Another potential snowstorm, tracking through our region from late Tuesday into Wednesday, is under close observation. While there's significant uncertainty about this system's development, it's highly probable that some areas in Ontario will receive over 30cm of snow.

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Snow has already started in Northwestern Ontario, near the international border, as of Friday evening. This snowfall is expected to intensify overnight and continue into Saturday morning. During these hours, the steady snow will gradually spread eastward, reaching Northeastern Ontario by the afternoon. Minor lake enhancement near Lake Superior might result in slightly heavier snowfall rates.

As we progress into Saturday night and early Sunday, the snowfall will start to diminish, beginning near the Manitoba border and extending to the rest of Northwestern Ontario by sunrise. In the east, snow is expected to persist through early Sunday but will gradually weaken by the afternoon.

The heaviest snowfall totals across Northern Ontario will be quite extensive. In Northwestern Ontario, the greatest accumulations are expected along the international border, extending east to Thunder Bay and along the Lake Superior shoreline. Here, snowfall is generally forecasted to range from 15 to 20cm, with potential local higher amounts, especially near Lake Superior, where the lake effect might cause uneven snow distribution.

Toward the Manitoba border, lesser snow is anticipated, with totals between 10 to 20cm expected for areas like Kenora, Dryden, and Red Lake.

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In contrast, Northeastern Ontario will see a more confined area with 15-20cm of snow, primarily east of Lake Superior due to lake enhancement effects. Broader regions, including Timmins, Kapuskasing, Kirkland Lake, and Sudbury, are likely to receive 10 to 15cm.

The southern areas along the Georgian Bay shoreline, such as North Bay and Manitoulin Island, will experience lower accumulations, ranging from 5 to 10cm.

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As the snow exits in the north, attention shifts to a secondary system poised to brush Southern Ontario's eastern edges. This snowfall is expected to start late Saturday afternoon, beginning in the Niagara region and gradually encompassing Eastern Ontario by night.

The interaction of this storm with the northern system adds an element of unpredictability to its trajectory. A westward shift in its path could mean more widespread snowfall, potentially affecting the Golden Horseshoe and Central Ontario.

However, current projections suggest a more eastern trajectory, which would result in higher snowfall rates in the eastern part of the province, especially close to the center of the low-pressure system. Lake Ontario may also contribute to locally enhanced snowfall rates, particularly in the Western Greater Toronto Area (GTA), between Hamilton and Toronto.

This snow is expected to continue through the night and into Sunday morning, with the heaviest snow likely occurring Saturday evening and early Sunday. By noon, snowfall should start tapering off in the southwestern regions, while light snow may persist over Eastern Ontario for much of the afternoon.

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Forecasting the accumulation from this storm is challenging due to the low confidence in its exact path. A shift to the east could reduce snow totals, while a westward shift might bring more snow into the GTA.

Currently, it's anticipated that Extreme Eastern Ontario, stretching from Kingston through Brockville to Cornwall, could experience snowfall exceeding 15cm, possibly reaching up to 20cm. However, some models indicate a possible underperformance, with totals closer to 10 to 15cm.

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The snowfall predictions decrease further west, with Ottawa and the Northern Lake Ontario shoreline expecting 10 to 15cm. A broad zone encompassing the rest of Eastern Ontario and parts of Central Ontario is forecasted to receive around 5cm, with slightly higher amounts of up to 10cm possible.

This includes the Golden Horseshoe around Lake Ontario and extends up along the Dundalk Highlands, where local areas might also see 5-10cm, depending largely on lake enhancement effects.

Less than 5cm is expected along the Georgian Bay shoreline and into Southwestern Ontario. The least snow, under 2cm, is forecasted for Deep Southwestern Ontario.

A separate update on the potential snowstorm for Tuesday will be released over the weekend. Currently, there's too much disagreement among models to confidently predict this forecast.

January 02, 2024

First Snowy Blast of the Year Could Bring Up to 5-10cm of Snow to Parts of Ontario on Wednesday

January 02, 2024/ Brennen Perry

Many people across Southern Ontario welcomed the New Year amid snowy conditions, as an overperforming system brought up to 5-10cm of snow locally. The heaviest snowfall occurred in the Golden Horseshoe and Kitchener areas, where heavy snow bands persisted throughout New Year’s Eve.

The snow on New Year’s Eve might just be a precursor to what lies ahead, with more snow forecasted for the first week of 2024!

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A disorganized system is poised to move across Ontario from late Tuesday evening. This system, in isolation, would likely only result in a light dusting of snow. However, the combination of dropping temperatures and the ice-free Great Lakes will likely amplify snowfall in the traditional snowbelt areas thanks to some lake enhancement.

Starting around midnight, light to moderate snowfall is expected, continuing overnight into Wednesday morning. It will begin in Northern Ontario and gradually spread southward by early Wednesday. Heavier snow bands are anticipated near the eastern shores of Georgian Bay and Lake Huron, primarily impacting the Grey-Bruce area, along with Muskoka and Parry Sound.

Further from the lakes, snow will be more sporadic, as the system's main moisture concentration will be near Northeastern Ontario along the Quebec border and more dependent on enhancement from the lakes. Southern Ontario should anticipate intermittent snow throughout Wednesday, while in Northern Ontario, it's expected to ease off by Wednesday afternoon.

Lake effect snowfall will persist off Lake Huron and Georgian Bay into the afternoon and evening. Overnight, these lake effect bands will likely shift southwards with the changing wind direction, potentially bringing a few hours of heavy snow to areas south and southeast of Lake Huron and Georgian Bay in the early hours of Thursday. However, these bands should weaken by sunrise.

By late Thursday morning, the snowfall across all regions is expected to cease as the system driving the lake-effect snow departs.

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As previously mentioned, the heaviest snow accumulation is anticipated in the typical snowbelt areas around Lake Huron and Georgian Bay. In locales such as Goderich, Kincardine, Owen Sound, Collingwood, Parry Sound, Bracebridge, Huntsville, and Algonquin Park, snowfall totals are likely to range from 5 to 10cm.

In such lake-influenced events, it's important to note that total accumulations will vary considerably based on location, with some areas potentially receiving over 10cm.

Elsewhere in Southern Ontario, less than 5cm of snow is expected, with only trace amounts for Deep Southwestern Ontario, the Golden Horseshoe, and Eastern Ontario.

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In Northern Ontario, the heaviest snowfall is forecasted for Northeastern Ontario near the Quebec border, affecting Chapleau, Timmins, Kapuskasing, Cochrane, Timmins, and Kirkland Land, with expected snowfall of 5 to 10cm by midday Wednesday.

The rest of Northeastern Ontario will receive a few centimeters of fresh snow, while minimal accumulation is projected for Northwestern Ontario.

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Ontario Forecasts

Late Friday Wind Storm to Give Way to a Snowy Start to the Weekend in Parts of Ontario With Up to 10cm of Snow

Winter Storm Threat Looms for Ontario With Up to 30cm of Snow and 60mm of Rain by Thursday

Potential Snowy Start to April With Up to 20cm in Parts of Southern Ontario Starting Tuesday

Biggest Snowfall of the Season Possible in Parts of Southern Ontario Including Toronto on Friday With Up to 10-20cm of Snow

Lake Effect Snow Targets Parts of Southern Ontario With Over 20cm of Snow Possible by Thursday

Ontario to Welcome the First Day of Astronomical Spring With Up to 15-25cm of Snow Between Tuesday & Wednesday

Winter Is Not Done Yet! Parts of Southern Ontario Could See Up to 10-20cm of Snow by Monday

Snow Squall Accumulation Disclaimer

Messy System Targets Ontario This Weekend With Significant Rain to the South and Heavy Snow to the North

From Record-Breaking Heat to Blizzard; Snow Squalls Could Dump Upwards of 15-30cm on Parts of Ontario by Thursday

Snow Squall Accumulation Disclaimer

Snow Squalls Could Dump Up to 20-40cm of Snow on Parts of Ontario’s Snowbelt This Weekend

Snow Squall Accumulation Disclaimer

Potential Snowstorm on the Horizon for Southern Ontario; Up to 20–30cm of Snow Possible on Thursday

FORECAST UPDATE - FEB. 15 @ 10:55 AM

earlier forecast

Say It Ain’t Snow! Winter Returns to Southern Ontario With Up to 10-20cm of Snow on Thursday

Snow Squalls Return to Southern Ontario’s Snowbelt This Weekend With Up to 25-50cm Possible

Relentless Snow Squalls to Bury Parts of Ontario’s Snowbelt in Up to a METRE (100cm) of Snow by Wednesday

Multi-Day Snow Squall Event Could Dump Up to 50cm of Snow on Parts of Ontario’s Snowbelt by Monday

Intense Blast of Snow on Friday Evening Could Bring Blizzard Conditions & Up to 20-30cm of Snow to Parts of Ontario

Get Your Shovels, Southern Ontario! The First Major Snowstorm of the Season Is on the Way This Weekend

Winter Storm Threatens Tuesday Evening Commute Across Ontario Including the GTA; Significant Snowfall to the North With Up to 35cm Possible

Parade of Snowstorms Take Aim at Ontario Over the Next Week Beginning With Up to 15-20cm of Snow This Weekend

First Snowy Blast of the Year Could Bring Up to 5-10cm of Snow to Parts of Ontario on Wednesday

WE ARE COMMITTED TO PROVIDING ACCURATE AND RELIABLE FORECASTS

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