Muggy air fuels severe thunderstorm threat in Ontario Thursday

A robust system is set to impact Ontario on Thursday, bringing widespread risks of severe thunderstorms.

DON'T MISS: A normal July brings Canada drought, downpours, and dizzying heat

The primary hazards associated with these storms are heavy rain, large hail, and potentially damaging winds. Residents are urged to remain vigilant as conditions evolve.

Storm threat builds through Thursday: Risk of large hail, powerful winds

A warm, humid air mass with humidex values in the mid-30s is fuelling the potential for intense storms. Rain and embedded thunderstorms will first develop Thursday morning over northeastern and eastern Ontario along a warm front.

By early afternoon, southern Ontario will become unstable as the main low pressure system advances, enhancing thunderstorm activity.

Severe storms are forecast to begin near the Lake Huron shoreline around 11 a.m., reaching the Greater Toronto Area (GTA) by 1–2 p.m. Impacts to major highways (401, 404, and 400) are anticipated.

Key threats include heavy rainfall, strong winds, and hail up to the size of toonies. Eastern Ontario could see linear storm patterns capable of producing damaging wind gusts nearing 100 km/h.

RELATED: From drips to disasters: How to flood-proof your home

By late afternoon and evening, storms will approach Ottawa and trigger along the cold front in southwestern Ontario, including Hamilton and the western GTA. Commuters in Ottawa should prepare for stormy conditions during rush hour.

Stay tuned for updates and monitor alerts as this system evolves.