Spring Snowstorm Could Dump Up to 20cm of Snow on Parts of Southern Ontario to Start the Week
/After an active month of wintry weather across Southern Ontario, March has taken a much calmer turn, bringing spring-like temperatures and even double-digit highs in some areas. However, don’t be fooled by the recent warmth—winter isn’t quite done with us yet. Despite what the calendar says, a surge of colder air will take over for the final days of March, setting the stage for a late-season snowstorm on the horizon.
An organized system is expected to bring heavy snow to parts of Southern Ontario starting late Sunday evening and continuing into Monday. Mixed precipitation will likely limit snowfall accumulation along the Lake Ontario and Lake Erie shorelines. However, further north, particularly around Georgian Bay, lake enhancement could boost totals, with some areas seeing 10-20 cm of snow. This storm could bring the most substantial snowfall in weeks, potentially impacting the Monday morning commute.
In addition to the snow, strong winds will develop on Monday morning and afternoon, with gusts reaching 50 to 70 km/h. This will lead to blowing snow and reduced visibility, especially in areas prone to drifting, such as Grey-Bruce.
PRECIPITATION TYPE - MAP FROM WEATHERBELL
The messy weather is set to arrive Sunday evening, with the first bands of precipitation moving into Southwestern Ontario. However, the forecast remains tricky due to overnight warming temperatures. Some areas will start off with wet snow before transitioning to rain, especially near Lake Ontario and Lake Erie.
For Deep Southwestern Ontario, including Windsor, Chatham, Sarnia, and the Niagara region, snowfall will likely be limited as these areas will see mainly rain or a quick changeover from snow to rain after only a few hours. London, Goderich, and Kitchener will see more prolonged snowfall through the overnight hours, though freezing rain and ice pellets may mix in at times.
PRECIPITATION TYPE - MAP FROM WEATHERBELL
The heaviest snow is expected to move into Central and Eastern Ontario by the pre-dawn hours of Monday, with several hours of steady snowfall along the leading edge of the system. However, since temperatures will be rising overnight, some of this snow may struggle to accumulate, particularly on road surfaces. Areas near the Lake Ontario shoreline may also see a mix of snow, rain, and ice pellets rather than steady snowfall.
By Monday morning, snow will continue spreading northeast, reaching the Ottawa Valley by sunrise. Given the timing, the snow could create challenging travel conditions during the morning commute, with reduced visibility and slushy roads. School bus cancellations may be possible in rural parts of Central and Eastern Ontario.
PRECIPITATION TYPE - MAP FROM WEATHERBELL
While the widespread snowfall will taper off by late morning or early afternoon, lingering snow is expected around Lake Huron and Georgian Bay, where lake enhancement could lead to heavier localized snowfall. Grey-Bruce, Parry Sound, and North Bay will be among the hardest-hit areas, with additional accumulations into Monday night.
Meanwhile, for Eastern Ontario and the Golden Horseshoe, the bulk of the snow will be finished by midday Monday. However, light lake-effect snow will persist in the snowbelt regions throughout the rest of Monday into Tuesday. Some weak snow squalls could occasionally drift into Eastern Ontario and the Greater Toronto Area (GTA), but accumulation will be minimal outside of the snowbelt zones.
By the time the system exits Monday evening, the highest snowfall totals will likely be in Bruce Peninsula, northeast Georgian Bay, and Northern Ontario, including Tobermory, Manitoulin Island, Sudbury, Parry Sound, North Bay, and Huntsville. These areas are expected to see 10-20 cm, with locally higher amounts possible.
That said, above-freezing temperatures for several hours on Monday could lead to melting and compacting of the snow, potentially reducing overall accumulations from what falls initially.
For Central Ontario, including Kitchener, Orangeville, Hanover, Owen Sound, Collingwood, Midland, Orillia, Bracebridge, and Bancroft, snowfall totals will generally range between 5-10 cm by Monday evening. However, some areas east of Lake Huron may see slightly higher totals, depending on lake enhancement.
For the Ottawa Valley, Southwestern Ontario, and the Golden Horseshoe away from the lakeshores, accumulations will likely stay under 5 cm. These areas may see a few centimetres of wet snow Sunday night, but overall, nothing significant is expected.
Regions directly along the Lake Ontario and Erie shorelines, as well as Deep Southwestern Ontario, will see little to no snowfall as rain or mixed precipitation will dominate.
Beyond Monday, lake-effect snow will persist into Tuesday, mainly affecting areas around Lake Huron and Georgian Bay, where localized snow squalls could bring a few extra centimetres.