Isolated Storms Could Bring Tornado Risk to Central Ontario and GTA on Wednesday
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As we near the end of what has been a relatively quiet month for weather across Southern Ontario, we’ve been locked in a pattern of calm conditions and unseasonably warm temperatures. But now, as we enter the first week of autumn, a shift is on the horizon!
Rainy weather has returned across much of Southern Ontario over the past few days, and unsettled conditions are expected to continue into Wednesday. There’s also potential for severe weather during the late morning, extending into the afternoon.
RAINFALL WARNING (IN GREEN) ISSUED BY ENVIRONMENT cANADA
We’re already seeing pockets of heavy rain and thunderstorms overnight, which are expected to persist until sunrise. Environment Canada has issued rainfall warnings for some areas, where localized amounts of up to 50 mm are possible.
While it's uncertain, some models indicate a slight tornado risk in the morning, particularly around the Golden Horseshoe and Niagara Region. Though this is unlikely, it’s still worth noting.
The timing of when these overnight storms clear out will be key in determining the risk for later in the morning and afternoon. According to the latest models, most storms should dissipate by sunrise, allowing the atmosphere to become more unstable heading into the late morning.
From around 11 AM through early afternoon, conditions could become favorable for isolated thunderstorms. The strongest setup is expected around Lake Simcoe, extending into the Muskoka and Haliburton regions.
While most storms are expected to remain non-severe, there is a chance of isolated tornadoes, along with marginally severe wind gusts and hail up to the size of quarters.
The Greater Toronto Area and Niagara Region are under a marginal risk for severe weather, primarily due to the potential for an isolated tornado during the afternoon and early evening. This marginal tornado risk also extends into Algonquin Park and parts of southwestern Quebec.
It’s important to keep in mind that this forecast has a high bust potential—some models show little storm development during peak hours of instability. This forecast assumes storms will develop during the afternoon, but we may need to update and downgrade the risk in the morning if it looks less likely that storms will form.
