ONTARIO: Thunderstorm Forecast for Thursday, August 10, 2023
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As we look ahead to Thursday, there's a growing risk of severe thunderstorms, and we have made some important changes to our forecast. Here's what you need to know:
We've updated our thunderstorm risk forecast to include a 'strong' chance of severe storms, covering a large area from Lake Huron through Lake Simcoe and extending into parts of the Ottawa Valley. Also, Central and Eastern Ontario, including the Greater Toronto Area (GTA), are now under a 'slight' risk. This means we're seeing the potential for stronger storms than previously thought, especially in those areas.
The timing of storm development has shifted a bit. We expect isolated storms to kick off sometime between 11 am and 2 pm. These storms are likely to pop up around Owen Sound and Georgian Bay before moving inland during the early afternoon.
The environment is favourable for some of these storms to become supercells around Lake Simcoe and south of Georgian Bay. These storms have the potential to bring threats including hail up to the size of golf balls and damaging wind gusts reaching up to 110 km/h. We could also see one or two tornadoes if these storms manage to get rotating which the environment could support.
As the day goes on, the focus of the storm threat will shift eastward. Isolated storms will come together to form a line of storms. We may even see a few isolated supercells ahead of the main line throughout the Ottawa Valley which would present a buffet of storm threats including large hail, destructive wind gusts and tornadoes. Throughout this line of storms, the main worry is strong winds that could cause damage. But, we can't ignore the possibility of large hail and a few isolated tornadoes either.
We're also keeping an eye on Southwestern Ontario, where we could see isolated storms forming off Lake Huron. This might affect places like Goderich and Kitchener-Waterloo, but it's a bit uncertain at the moment.
By the late afternoon, the severe weather risk should start to decrease from west to east.
