Heavy rain, localized flooding possible in southern Ontario this week

Digital WritersThe Weather Network
Digital Writers

Intense rainfall is expected to sweep across southern Ontario during the start of this week.

A moist system is tracking into the Great Lakes region and is bringing the risk for thunderstorms and flooding along its cold front.

Southern Ontario will be in the warm sector of the system on Monday afternoon, which means conditions will largely remain seasonal and dry with a chance for a passing shower north of the Greater Toronto Area (GTA).

However, the main event ramps up Monday evening as the cold front slides across Lake Huron.

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The cold front could result in training thunderstorms for Winsor, Sarnia, and the Grey Bruce region. Training thunderstorms line up one behind another and move over the same region, often resulting in repeated rainfall and high accumulations, which increases the risk for localized flooding.

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Forecasters say that some models disagree with the exact timing and the location of the heavy rain, however, signs are pointing towards considerable rainfall along the Huron shores on Monday evening and overnight.

In Grey-Bruce and cottage country, rainfall totals could range from 25-50 mm with higher accumulations in areas that experience thunderstorms on Monday evening into Tuesday morning.

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Nocturnal thunderstorms are also on the table as the cold front presses on towards Highway 401 and the GTA during the pre-dawn hours on Tuesday.

Embedded lightning and thunder may wake up Toronto residents early Tuesday, who could then be met with a soggy morning commute.

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Stay tuned to The Weather Network for all the latest on conditions across Ontario.