Potential Snowy Start to April With Up to 20cm in Parts of Southern Ontario Starting Tuesday
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April Fools' Day might be on Monday, but the first week of April is shaping up to be no laughing matter in terms of weather for Southern Ontario. Starting Monday, the lower Great Lakes region is expected to be impacted by a series of systems throughout the week.
The initial two systems are projected to track south of the border, impacting Ohio and Pennsylvania primarily. There's a risk of severe weather on Monday and Tuesday, with a possibility it could extend into Deep Southwestern Ontario. However, the cold waters of Lake Erie should keep most of the severe risk south of the border. We will be monitoring and will have a forecast if it becomes more certain to have an impact on our region.
These systems are set to bring heavy rain across the Lake Erie shoreline, from Sarnia to the Niagara Region and southward, with some areas potentially receiving 10-20mm of rain from Sunday night into Tuesday morning.
By late Tuesday, a third system is expected to sweep across Southern Ontario, bringing heavy rain throughout Tuesday afternoon and evening for most regions. Temperatures are set to drop from the low to mid-single digits to around or slightly below the freezing mark, causing the rain to transition to snow overnight into Wednesday morning.
The extent of this changeover, however, remains uncertain. Areas near the Lake Ontario shoreline and Deep Southwestern Ontario are likely to remain warm enough to prevent significant snow accumulation. In contrast, Central and Eastern Ontario, along with the higher elevations of the Dundalk Highlands northwest of the GTA, may experience sustained snowfall.
This snow is expected to persist into Wednesday, with moderate to heavy snowfall continuing into the evening. Strong wind gusts may also contribute to blowing snow and reduced visibility in some areas. Light snow may linger into Thursday for Central and Eastern Ontario, but it won’t lead to much accumulation.
This forecast is preliminary and subject to changes as the system's path and temperatures near the freezing point could significantly affect overall snowfall accumulation.
As of now, Central and Eastern Ontario, including the Ottawa Valley and Muskoka, are anticipated to see 10-20cm of snow. The higher elevations of Algonquin Park and the Ottawa Valley are expected to be closer to the 20cm mark, with Ottawa and Muskoka likely receiving 10-15cm.
The Dundalk Highlands area could see heavier snowfall, with Orangeville and Shelburne potentially receiving the most, possibly up to 10-20cm. However, this forecast is less certain due to temperature variations that may prevent freezing and cause some melting.
The rest of Central Ontario and the northern part of the GTA could receive 5 to 10cm by Thursday, with the possibility of higher totals if temperatures drop further than currently expected.
Areas near Lake Ontario's shoreline, the Niagara region, and the Lake Erie shoreline are expected to see less snow, with less than 5cm of accumulation. However, significant rainfall poses a concern for these areas, with potential localized flooding due to upwards of 50mm of rain.
We will continue to monitor the latest data and provide a more detailed forecast shortly. Remember, this forecast is very preliminary and could change significantly by Tuesday.
