Multi-day severe storm, tornado risk builds in Ontario and Quebec
The storm risk slides south and east for Wednesday and Thursday, with severe weather on tap for parts of eastern Ontario and southern Quebec
The next two days will again feature prime conditions for stormy weather in Ontario and Quebec.
Wednesday's storm potential will be more sporadic and non-severe, with stronger storm dynamics and a risk of tornadoes near Saguenay, Que. Thursday will be a day to watch more closely, however, particularly in eastern Ontario and southern Quebec, as the recent high heat and humidity are providing ample storm energy across the province.
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The Laurentians in Quebec will have favourable, atmospheric conditions for tornado development on Thursday, while other areas west of there and eastern Ontario could see flooding.
You'll want to stay updated on the weather alerts in your area as conditions can change quickly when severe weather hits.
Wednesday: More widespread storm risk, slight tornado risk in Quebec
The active weather boundary shifts south slightly across Ontario on Wednesday, also moving into Quebec.
We could see severe storms develop along the boundary over Quebec, near Saguenay. Here we'll see a slight risk of one or two tornadoes spinning up, and a larger risk for 30+ mm rainfall and 2+ cm hail.
Non-severe storms may develop from Sault Ste. Marie to Sudbury, tracking east into Quebec. Isolated thunderstorms with heavy rain will be possible in southwestern Ontario--depending on the strength of the lake breezes.
Thursday: Ample thunderstorm energy leads to strong storms, tornado risk
Forecasters are keeping a close eye on Thursday, with a low-pressure system and strong cold front expected to bring more severe weather to eastern Ontario and southern Quebec. The system will track over the Great Lakes Thursday morning and continue eastward through the day.
Ample thunderstorm energy, fuelled by several days of 30°C heat and high humidity, could lead to strong thunderstorms with torrential downpours. Between 50-100 mm of heavy rainfall is possible under storms, increasing the risk of localized flooding.
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Non-severe thunderstorms are expected to move through the Greater Toronto Area (GTA) before peak afternoon energy develops.
Thunderstorm energy will be abundant by the afternoon hours, with ample moisture, and signs of notable shear will result in strong and severe storm clusters over the Ottawa Valley and southern Quebec.
The Ottawa and St. Lawrence valleys will be concerned with flooding potential, while tornado ingredients may be present north of the Ottawa Valley and over the Laurentians, although confidence is still low and conditions are being closely monitored by forecasters.
The active weather will be followed by a welcome cooldown, offering relief from the heat.
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Stay with The Weather Network for all the latest on conditions across Ontario and Quebec.