Severe Storms Could Bring Golf Ball-Sized Hail & Isolated Tornado Risk to Parts of Southwestern Ontario Late Tuesday

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Are Tornado Tuesdays making a comeback this year in Southern Ontario? It seems that the first full week of May will begin on a stormy note, with a looming severe thunderstorm risk starting Tuesday evening in Deep Southwestern Ontario.

However, the severe threat will be very localized, focusing on Windsor, Amherstburg, Pelee Island, and Leamington. Based on the latest data, the environment in these areas could support the development of storms capable of producing large hail.

Severe wind gusts are also possible, but the main concern is hail, as these storms are expected to be fairly elevated. The hail could be quite large, potentially reaching the size of ping-pong balls or even golf balls.

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Regarding the tornado threat, the elevated nature of these storms should limit the potential for any rotation to reach the surface and produce a tornado.

However, there is a fairly strong environment stateside that could support tornadic activity, and we can’t completely rule out a rogue storm. This is especially true around Leamington and Pelee Island, where the environment is strongest.

Isolated storms are expected to begin popping up over Indiana, Michigan, and Ohio sometime during the late afternoon and early evening. This is where the severe risk will be the strongest, likely leading to several tornadoes and very large hail.

As these storms mature later in the evening, they will track towards Deep Southwestern Ontario around 8 to 11 PM. There is some uncertainty about how well these storms will maintain their strength due to the lack of daylight heating and the cold waters of Lake Erie, which prevent the environment from extending too far north into our region. If the storms arrive earlier than expected, the severe threat could increase, as daylight heating will still be in effect and help fuel the storms.

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Widespread non-severe thunderstorm activity is expected to spread across Southwestern Ontario and into parts of the Golden Horseshoe around midnight. At this point, the storms are not expected to pose any severe threats, but small hail and strong wind gusts cannot be completely ruled out.

Those around Georgian Bay and into Northeastern Ontario, including Sudbury and North Bay, could be awakened by some noisy storms early Wednesday morning. These storms are also expected to remain non-severe.

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UPDATE: Clouds May Move Out Just in Time for the Solar Eclipse on Monday in Parts of Southern Ontario at the Expense of Eastern Ontario

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We are on the eve of the total solar eclipse set to dim the skies across Southern Ontario on Monday. With the event about 24 hours away, our confidence in the viewing conditions within our region is sharpening. Clear skies are crucial for those looking to fully experience the eclipse, a phenomenon eagerly awaited by many for years.

The experience of a total solar eclipse differs significantly under clear versus cloudy skies. Clear conditions allow observers to witness the dramatic dimming of daylight, a noticeable drop in temperature, and the visibility of stars and planets.

The eclipse's most breathtaking moment, the emergence of the sun's corona, is visible only during totality, revealing delicate, radiant strands extending from the moon's silhouette, an image no camera or telescope capturing partial phases can replicate.

Under cloudy conditions, while some cooling and dimming effects may still be perceptible, the visual spectacle is significantly diminished. Clouds mask the corona, stars, and planets, greatly reducing the visual impact of the eclipse.

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SAFETY WARNING

To safely enjoy the eclipse, it's imperative to use ISO 12312-2 certified solar glasses. Directly observing the sun, even during an eclipse, can cause serious damage to your eyes. You can only view the eclipse without the glasses during the few minutes of totality. Solar glasses are designed to block harmful solar radiation and protect your eyes while allowing you to safely witness the event.

Never use makeshift viewing solutions like sunglasses or homemade filters, as they do not offer adequate protection against the sun's rays. Also, remember that the same rules apply to taking pictures with your phone. The sun can damage your camera’s sensors if you don’t have the proper solar filter (such as the same solar glasses for your eyes).

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your guide to the eclipse:

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Our initial forecast pointed to the possibility of clouds moving into Southern and Northern Ontario from late Sunday into Monday morning. This outlook holds, according to the latest models, albeit with slight adjustments in the anticipated locations of the densest cloud cover.

A key change concerns Eastern Ontario, where the front edge of the cloud cover is now forecasted to arrive several hours earlier than previously thought. Consequently, areas such as Kingston, Belleville, and Brockville might experience increasing cloudiness before the eclipse begins, potentially obscuring views of the later stages, including totality around 3 PM.

In the Ottawa Valley, cloud coverage remains a possibility, though a very narrow strip of Extreme Eastern Ontario, around Cornwall, is expected to maintain clear skies for the majority of the eclipse. While high-level clouds may still be present, they shouldn't hinder eclipse viewing, as the sun's light should penetrate through.

This shift in cloud movement toward the east spells good news for those in Deep Southwestern Ontario. We now have increased confidence that locations southwest of London, including Sarnia, Chatham, Leamington, and Windsor, will enjoy mostly clear skies at the eclipse's peak.

Even parts of Southwestern Ontario, extending from the southwestern shore of Lake Huron to the Kitchener/Waterloo region, might see clouds dissipate in time for the eclipse.

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The outlook for the Golden Horseshoe, including the Greater Toronto Area and Niagara region, is more uncertain. Clouds are expected to obscure the early stages of the eclipse in the afternoon, but recent high-resolution models suggest possible breaks in the cloud cover around 3 PM, coinciding with the eclipse's maximum.

There's hope that this trend towards earlier cloud clearance continues, potentially offering clear views over the Niagara region right in time for totality. While not guaranteed, the possibility remains, so keep your fingers crossed.

In contrast, Central Ontario and the Georgian Bay shoreline are expected to be under thick clouds during the eclipse, likely obstructing views. Those in these areas hoping to witness the eclipse may need to consider travelling to clearer locations.

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In Northern Ontario, prospects for viewing the partial solar eclipse are less favourable, with extensive cloud cover predicted from Georgian Bay to the Lake Superior shoreline.

Locations such as Elliot Lake, Sault Ste. Marie, Wawa, and Marathon are unlikely to have a clear view of the eclipse. Cloud coverage in Northeastern Ontario is expected to be mostly dense, though it may become more scattered further north.

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As we look at Northwestern Ontario, the viewing conditions are quite poor, especially around the Lake Superior shoreline including Thunder Bay, Kenora and the Armstrong region. Thick clouds will likely make the eclipse hard to view.

Clouds Threaten to Spoil the Solar Eclipse on Monday in Parts of Ontario but Not for Everyone

CLICK HERE FOR THE UPDATED FORECAST

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The countdown is on for the total solar eclipse set to darken the skies across Southern Ontario on Monday. As the big day approaches, we're gaining a clearer understanding of the expected weather conditions during the eclipse. Clear skies are essential for experiencing the full marvel of the eclipse, an event eagerly anticipated by many for years.

Experiencing a total solar eclipse varies dramatically under clear versus cloudy skies. Clear skies allow you to witness the significant dimming of daylight, a noticeable drop in temperature, and the emergence of stars and planets.

The eclipse's crowning moment, the visibility of the sun's corona, occurs exclusively during totality. This presents the corona's delicate, luminous strands extending from the moon's silhouette in a spectacle unmatched by any camera or telescope viewing partial phases.

However, under cloudy skies, though you may still observe a cooling and dimming effect, the visual wonder is significantly obscured. Clouds conceal the corona, stars, and planets, greatly diminishing the eclipse's visual splendour.

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SAFETY WARNING

To safely enjoy the eclipse, it's imperative to use ISO 12312-2 certified solar glasses. Directly observing the sun, even during an eclipse, can cause serious damage to your eyes. You can only view the eclipse without the glasses during the few minutes of totality. Solar glasses are designed to block harmful solar radiation and protect your eyes while allowing you to safely witness the event.

Never use makeshift viewing solutions like sunglasses or homemade filters, as they do not offer adequate protection against the sun's rays. Also, remember that the same rules apply to taking pictures with your phone. The sun can damage your camera’s sensors if you don’t have the proper solar filter (such as the same solar glasses for your eyes).

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your guide to the eclipse:

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The weather forecast offers a mix of optimism and caution. Some areas in the path of totality in Southern Ontario might face cloudy conditions, potentially obscuring the eclipse. Yet, certain regions in Eastern Ontario and along the Lake Erie shoreline are expected to enjoy clear skies, offering an unobstructed view of the eclipse.

The latest models predict clouds moving in from the southwest late Sunday, leading to overcast conditions in much of Southwestern, Central Ontario, and the Golden Horseshoe by Monday morning. These clouds are expected to spread eastward throughout the morning and early afternoon, with discrepancies among models regarding the extent and timing of the cloud cover.

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By early afternoon, clearing is anticipated in Deep Southwestern Ontario, just in time for the eclipse's start around 2 PM. In contrast, from Niagara Falls through the GTA to Central Ontario, clouds are likely to persist, though intermittent breaks might still offer glimpses of the eclipse.

Eastern Ontario faces a race against time, with increasing cloudiness expected. The northeastern tip, including Cornwall, may remain clear until later in the afternoon, offering potentially favourable conditions for eclipse viewing. Kingston and Belleville should be mostly clear to start, but again, clouds will increase in coverage during the eclipse so hopefully it can hold off until after totality occurs.

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In Northern Ontario, prospects for viewing the partial solar eclipse are less favourable, with extensive cloud cover predicted from Georgian Bay to the Lake Superior shoreline.

Locations such as Elliot Lake, Sault Ste. Marie, Wawa, and Marathon are unlikely to have a clear view of the eclipse. Cloud coverage in Northeastern Ontario is expected to be mostly dense, though it may become more scattered further north and east.

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As we look at Northwestern Ontario, the viewing conditions are quite poor especially around the Lake Superior shoreline including Thunder Bay and into the Armstrong region. Thick clouds will likely make the eclipse hard to view. There is some chance that those closer to the Manitoba border may see some breaks in the clouds, but it’s unlikely.

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

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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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DATA and chart FROM WEATHERSTATS.CA

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.

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

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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.

Possible ‘Heatwave’ to End February in Ontario?

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Are you ready to feel the heat, Ontario? 🥵

Confidence is growing for another surge of warmer temperatures as we move into the final week of February. Despite many enjoying a taste of winter weather last week across Southern Ontario, it seems that was merely a brief pause in the mild winter we have been experiencing this season.

As of Tuesday, the shift towards milder temperatures is already noticeable, with parts of Southwestern Ontario experiencing mid to upper single-digit temperatures. This marks a significant change from just a few days ago when overnight lows plunged into the negative teens!

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The rest of the week promises more of the same, with temperatures staying in the single digits, slightly above the seasonal average.

Additionally, we're anticipating some rain from late Wednesday into Thursday, with expected totals between 15-25mm. The heaviest rainfall is predicted along the Lake Erie and Lake Ontario shorelines as the center of the low-pressure system is forecasted to pass just south of the Great Lakes.

However, a brief cooldown is on the horizon for the weekend, leading to morning lows of -10 to -20°C throughout Central and Eastern Ontario on Saturday. Given the open state of the lakes, we might also see some lake effect snow in the usual snowbelt areas.

This cold snap will be short-lived, as temperatures above freezing are expected to return by Sunday, with even warmer air moving into the province for the last days of February.

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While it's too early to specify exact temperatures, it appears many areas will experience temperatures 15 to 20°C above the norm.

Typically, daytime temperatures around this time of year hover around 0°C, suggesting that by mid-next week, temperatures could reach the mid to upper teens, depending on your location.

The warmest air is anticipated in the southwestern region, including Sarnia, Windsor, and Chatham. For instance, our app is currently forecasting a high of 16°C in Windsor next Tuesday.

While not a certainty, there are indications of a possible thunderstorm risk around the middle of next week. Though unlikely to be severe, it's certainly something we'll be monitoring.

If you were hoping for winter to linger and compensate for the mild season we've experienced so far, it seems that won't be the case.

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

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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.

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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.

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

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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.

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earlier forecast

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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.

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

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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.

Willie Was Right! Early Spring-Like Weather for Southern Ontario; Record Breaking Double-Digit Temperatures on Friday

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At the beginning of February, Wiarton Willie, who did not see his shadow, predicted an early spring for Southern Ontario. It appears that Willie's prediction may indeed reflect the weather pattern as we approach the latter part of this week.

After enjoying several consecutive days of sunshine, this pleasant streak is unfortunately expected to end, with clouds and fog rolling in on Thursday and Friday. It will resemble a Vancouver Or Seattle winter, a trend that has been persistent over the last few months. Early Friday, Southern Ontario will see some scattered showers that will continue throughout the day, but these showers will bring with them a surge of warm air.

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In parts of Southwestern Ontario and areas of the Golden Horseshoe, temperatures could reach the 10°C mark on both Thursday and Friday. Friday is anticipated to be the warmest day, with temperatures in Deep Southwestern Ontario nearing the mid-teens. Most areas have temperature records ranging from 8°C to 12°C, records that might be shattered on Friday, according to current models.

Those in Windsor, Chatham, Sarnia, London, Woodstock, and Newmarket can expect maximum temperatures between 10 to 14°C, likely making this the warmest area in the province. Near the Lake Erie, Lake Huron, and Lake Ontario shorelines, as well as in the Barrie and Peterborough areas, it will still be quite warm, with temperatures ranging from 8 to 12°C.

In Central and Eastern Ontario, temperatures are predicted to be slightly cooler, falling short of double digits and ranging from 6 to 10°C. Further north, temperatures are expected to hover in the mid-single digits for Algonquin Park and Northeastern Ontario.

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In addition to the warmth, fog starting Wednesday night around Lake Erie and the Golden Horseshoe will pose a challenge, with near-zero visibility creating hazardous driving conditions. This may result in some school bus cancellations on Thursday and Friday mornings. The fog is expected to persist into the weekend.

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Looking ahead to next week, a return to seasonal temperatures around the freezing mark is expected in most areas. There are signs that we might enter a colder pattern by the end of next week, extending into mid-February, potentially bringing several opportunities for accumulating snow later in the month. However, it's still too early to confirm, and the forecast could change!

Canada’s Groundhogs, Lobster Split on if It Will Be an Early Spring This Year

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The curtain has fallen on Groundhog Day 2024, and the forecasts from our esteemed weather-predicting groundhogs—and a lone lobster—are in, offering a split decision that mirrors the vast and varied Canadian landscape.

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In the Maritimes, Shubenacadie Sam of Nova Scotia brought cheer with his prediction of an early spring, a sentiment supported by Quebec’s new groundhog meteorologist, who is carrying on the legacy of the late Fred la Marmotte with a similar spring-forward forecast.

Lucy the Lobster, however, provided a stark contrast, casting her shadow on the seabed and predicting a longer winter for Nova Scotia.

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The spring chorus was joined by Ontario's Wiarton Willie and the famed Punxsutawney Phil from the United States, both of whom failed to see their shadows, suggesting an early end to winter.

In a surprising twist, the story changed out in the Prairies, as Manitoba Merv observed his shadow, heralding six more weeks of winter.

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This chilly predictions was later seconded by Alberta's Balzac Billy, who also saw his shadow, adding weight to the wintry forecast.

Now, with an even split of three forecasts for an early spring and three for a prolonged winter, Canadians are left to wonder what the coming weeks will truly hold. Will the hopeful predictions of an early spring prevail, or will the winter warnings ring true?

With this mixed bag of predictions, the end of winter remains as mysterious as the weather itself. Only the passing of the weeks will reveal the true accuracy of our furry and clawed forecasters’ divinations.

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Another Icy Day Ahead for Eastern Ontario; Second Round of Prolonged Freezing Rain on Friday Morning

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After being coated in ice all day Wednesday, Eastern Ontario is bracing for another round of freezing rain on Friday. This upcoming bout of freezing rain is expected to impact many of the same areas that were heavily affected by Wednesday's icing event.

A system moving into Southern Ontario late Thursday will bring mostly rain to Southwestern Ontario and the Golden Horseshoe region.

However, this system will run into the cold air lingering over Eastern Ontario, which was responsible for Wednesday's significant freezing rain. This will lead to the development of more freezing rain, starting early Friday morning along the Dundalk Highlands and extending eastward into the Ottawa Valley.

Freezing rain is forecast to continue across Eastern Ontario throughout the morning and into the afternoon. By late Friday afternoon, we could see an additional 5-10mm of ice accumulation. Considering the existing layer of ice from the previous event, this additional freezing rain poses an increased risk of power outages and hazardous road conditions.

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Regarding ice accumulation, it's important to note that the amounts mentioned are general estimates of freezing rain from the sky. Actual ice accumulation on surfaces will vary depending on the surface type, and local dynamics are difficult to predict in a broad-scale forecast.

The heaviest icing is anticipated around Bancroft, Perth, Ottawa, and Cornwall, with around 5-10mm of ice accumulation possible. It's important to note that some models predict a changeover to regular rain by late morning, particularly in the southern regions, which could limit total ice accumulation.

Elsewhere in Eastern Ontario, ice accretion of 2 to 5mm is expected before transitioning to rain. While the Kingston area was severely impacted by the last event, temperatures are forecast to rise above freezing quickly enough to prevent significant icing along the Lake Ontario shoreline.

Additionally, higher elevations northwest of the Greater Toronto Area, including Orangeville and Shelburne, may experience a few millimetres of ice as the cold air persists for a longer duration.

In Central Ontario, including Muskoka, Simcoe County, and northern parts of the Greater Toronto Area, some freezing drizzle is possible, but less than 2mm of ice accumulation is expected, as the conditions should quickly change over to rain.

Also notable is that parts of Southwestern Ontario could pick up around 15-30mm of rain during the overnight and into Friday morning. The rest of Southern Ontario not seeing the freezing rain can expect 10-20mm of rain, locally up to 25mm. All precipitation will come to an end by the dinner hour.

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Significant Freezing Rain Threat for Eastern Ontario Including Ottawa & Kingston on Wednesday

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An approaching system is set to move across Southern Ontario later on Wednesday, leading to a prolonged risk of freezing rain in much of Eastern Ontario. This system will bring warmer air, resulting in foggy and rainy conditions throughout Southwestern Ontario and the Golden Horseshoe area.

As the system advances northeast, it will encounter temperatures below freezing at the surface in Eastern and Central Ontario. The warm air will overtake the colder air aloft, creating ideal conditions for freezing rain.

Current forecasts indicate that the risk of freezing rain could last between 6 to 12 hours in parts of Eastern Ontario, beginning Wednesday afternoon and continuing through the evening into the early hours of Thursday.

In the hardest-hit regions, significant icing is possible, with more than 10mm of accumulation expected by early Thursday morning. This is likely to lead to icy road conditions and potential power outages as ice builds up on tree branches and power lines.

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Through the morning hours, drizzle and fog have already been affecting Southwestern Ontario and the Greater Toronto Area. This precipitation is expected to spread northward in the afternoon, meeting the colder air and forming a band of freezing rain from Lake Simcoe eastward through Peterborough to Kingston by mid-afternoon.

This freezing rain will persist, causing steady icing throughout the afternoon and evening. However, there is some disagreement among the models about how long the below-freezing temperatures will last. Some models suggest a gradual warm-up by evening in areas around Lake Simcoe and the Lake Ontario shoreline, which could lessen the ice accumulation in the Muskoka, Belleville, and Kingston regions.

Other models, however, indicate that the cold air will remain firmly in place with little temperature fluctuation until Thursday morning. This scenario would result in widespread icing from this afternoon into early Thursday.

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In the Ottawa Valley, especially south of Ottawa, there is more confidence in the forecast. Conditions are expected to be prime for freezing rain from late afternoon into the overnight hours. Further north, in regions like Pembroke, Renfrew, and Ottawa, ice pellets may mix in, leading to less icing but still severe impacts on travel and power.

The freezing rain is expected to taper off in the early hours of Thursday, but with temperatures remaining low in Eastern Ontario, travel conditions will still be treacherous for the Thursday morning commute. Widespread school bus cancellations are likely in this region on Thursday.

Fog will persist in Southwestern Ontario and the GTA. While it may recede slightly later on Wednesday, it's likely to return overnight in some areas.

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Regarding ice accumulation, it's important to note that the amounts mentioned are general estimates of freezing rain from the sky. Actual ice accumulation on surfaces will vary depending on the surface type, and local dynamics are difficult to predict in a broad-scale forecast.

The heaviest ice accumulation is expected between Ottawa and Kingston, with areas like Brockville, Smiths Falls, Perth, Tweed, and Bancroft potentially seeing up to 10 to 15mm of freezing rain. Other parts of Eastern Ontario, including Ottawa, Kingston, and Peterborough, are likely to experience several hours of freezing rain, with ice accumulations ranging from 5 to 10mm.

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In Central Ontario and parts of the GTA, lesser amounts of freezing rain are forecast, with around 2-5mm of ice possible for Muskoka, Kawartha Lakes, and parts of York and Durham regions. Less than 2mm is expected for Simcoe County and higher elevations northwest of the GTA. However, these areas could see higher amounts depending on how quickly temperatures rise above freezing.

Messy Week Ahead as Multiple Rounds of Heavy Snow and Freezing Rain Target Southern Ontario Starting Tuesday

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After a mild start in December, the new year has brought a shift in the weather pattern across Southern Ontario. January has definitely felt more like winter, with our first prolonged deep freeze leading to several instances of snow squalls in the past few weeks.

However, it seems the winter spell is about to break as we welcome milder air for the final days of January. The warm-up won't be uniform across the region, though. For instance, the Ottawa Valley and northern parts of Central Ontario will continue to experience colder temperatures, with overnight lows below -10°C and wind chills near -20°C for much of the week.

In contrast, areas in Southwestern Ontario and around the Golden Horseshoe are expected to see temperatures closer to, or even slightly above, the freezing mark later this week.

Several systems are forecast to move across Southern Ontario in the coming days. With temperatures hovering around freezing, these systems are likely to bring a mix of winter weather, including heavy snow, ice pellets, freezing rain, and even some regular rain.

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The first system is set to impact Southern Ontario late Monday, continuing through Tuesday. This could affect the Tuesday morning commute, particularly in Southwestern Ontario and the Greater Toronto Area.

Current predictions indicate that precipitation will primarily be heavy snow, stretching from Lake Huron across the Golden Horseshoe and into southern parts of Central and Eastern Ontario. By Tuesday's end, total snowfall could reach up to 10cm in some areas.

A more complex situation is expected further south in Deep Southwestern Ontario and along the Lake Erie shoreline. A mix of snow, ice pellets, and prolonged freezing rain could lead to icy road conditions in this region.

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Light snow and ice pellets have already started in Southern Ontario as of Monday afternoon, ahead of the main system. This is expected to taper off through the evening, though some patchy freezing drizzle could persist around the Lake Erie shoreline.

The initial bands of precipitation associated with the system will reach the Windsor area around midnight, with freezing rain being the primary concern. This risk will continue overnight and spread to Chatham and Sarnia by mid-morning Tuesday, making for potentially icy roads and delays. School bus cancellations are also a possibility due to the freezing rain threat.

By lunchtime Tuesday, the slow-moving system should reach London, Kitchener, Hamilton, and Toronto. It will likely start as light to moderate snowfall, continuing into the evening. Although the snowfall rates may not be intense, the prolonged nature of the event means that even a centimetre or two per hour will accumulate significantly over 6-12 hours.

Later in the afternoon, areas in Deep Southwestern Ontario and along the Lake Erie shoreline should warm up enough to transition from freezing rain to regular rain. A similar changeover to ice pellets and freezing rain is anticipated in the London to Hamilton corridor by evening, possibly resulting in slightly lower snowfall totals compared to areas further north.

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Snow is expected to begin in the southern part of Central and Eastern Ontario, from Barrie to Kingston, in the late afternoon or early evening, continuing overnight into Wednesday morning. Further north, areas like Huntsville, Algonquin Park, and Ottawa can expect less snow, as the heaviest precipitation is forecast to remain south.

The system should start clearing from west to east just after midnight and exit the province by late Wednesday morning. However, a brief respite in precipitation will be followed by another wave of moisture from the southwest late Wednesday.

This next system looks to bring more rain for Southwestern Ontario and the Golden Horseshoe, while Central and Eastern Ontario could face a prolonged risk of freezing rain lasting into Thursday. Further details on this will be provided in a separate forecast.

The impact of the first system will vary significantly. Regions east of Lake Huron through the Kitchener area and around the Greater Toronto Area are likely to see mostly snow, with additional accumulations of 6 to 12cm by the end of Tuesday. Lower snowfall amounts of 2 to 6cm are expected further north in parts of Central and Eastern Ontario.

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The situation becomes more complex southwestward, with a zone stretching from Sarnia through London to the Hamilton/Niagara region likely to experience a mix of ice pellets and snow. A few centimetres of ice pellets, along with up to 4-8cm of snow, is possible here. Brief freezing rain later on Tuesday shouldn't be ruled out as the mixing line moves northward.

In Deep Southwestern Ontario and along the Lake Erie shoreline, the primary risk is ice pellets and freezing rain. The precipitation will likely start as ice pellets early Tuesday, transitioning to freezing rain by late morning or early afternoon. Some rain may also occur in the evening as temperatures rise above freezing. Total accumulations are hard to gauge, but expect around 2-6cm of snow, followed by up to 2cm of ice pellets, and then several hours of freezing rain.

The Windsor and Chatham areas are forecast to see mostly freezing rain from this system, with ice accumulation up to 2-4mm before transitioning to regular rain. There could also be 10-15mm of rain from the system after the switchover occurs.

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

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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.

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

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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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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.

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

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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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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 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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Blizzard Risk for Southern Ontario on Friday; When Will It Arrive?

Southern Ontario is currently on track to see a high-impact snowstorm starting Friday evening. This storm will bring a brief, but intense burst of snow leading to blizzard conditions in many areas.

Here's a region-based breakdown of the estimated timing. Please note that these are estimates, and actual start times may vary by a few hours. However, this should give you a general idea of when to expect the worst conditions.

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The blizzard is expected to begin in Deep Southwestern Ontario in the late afternoon or early evening. Areas like Windsor, Chatham, and Sarnia will likely see conditions worsen between 5-7 PM.

Once the blizzard conditions arrive, they will last for one or two hours before gradually reducing in intensity with moderate snow continuing into Saturday. Although the wind will remain a concern throughout the night so expect some blowing snow.

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As the heavy snow band moves northeast, it will reach the London, Kitchener, and Goderich area shortly after dinner. The GTA, Hamilton, and Niagara regions should brace for the blizzard around 8-9 PM. Note that some of these areas might have mixed precipitation, which could reduce the severity of the blizzard.

Later in the evening, Central Ontario, including Simcoe County, Kawartha, Peterborough, and Muskoka, will experience heavy snow and strong winds. This is expected to start between 9-10 PM in the south and around 11 PM in the northern areas.

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Eastern Ontario, including Kingston and the Ottawa Valley, will likely see the blizzard start around 10 PM and around midnight, respectively.

Since it's not feasible to include every location in our graphic, we recommend using the closest listed location for guidance.

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

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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.

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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.

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

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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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