Ontario thunderstorms build Monday evening in Sudbury Weather

Sudbury weather turns unsettled Monday as a risk for strong to severe thunderstorms builds across southern and central Ontario through the day. A cold front approaches Monday afternoon and evening, with the most serious storms possible near Lake Huron, Georgian Bay and cottage country.

Georgian Bay Monday evening

Forecasters say strong, potentially damaging winds and large hail are the primary threats. They also list a slight risk of a tornado Monday evening near and northeast of Georgian Bay, which puts that corridor in the most closely watched part of the setup.

Monday brought the first 30-degree day of the year at Pearson International Airport, and the week starts with a summer-like pattern across the region. Temperatures are expected to fall off sharply closer to the shores, leaving a narrow zone where storms can organize as the front moves through.

Southern Ontario Tuesday

Another low-pressure system developing to the west will push additional warm air into southern Ontario for Tuesday. Some storm activity is expected later Tuesday evening and into the overnight hours, but forecaster confidence is low for that marginal severe-weather threat.

For readers across southern and central Ontario, the practical takeaway is to plan for changing conditions Monday afternoon into evening and keep an eye on the western side of the province again Tuesday. The most dangerous period in this forecast remains Monday evening near Georgian Bay, where the tornado risk is small but specific and the wind and hail threat is broader.