High temperatures, humidity and an approaching cold front are expected to brew up some of the most severe thunderstorms seen in the province so far this year on Tuesday afternoon, according to meteorologists.
- Joyce Li, Elissa Mendes, Vanessa Tiberio
“Damaging” supercell thunderstorms are forecast to hit parts of Ontario, including the Greater º£½ÇÉçÇø¹ÙÍøArea, potentially bringing with them wind speeds exceeding 100 km/h and hail stones up to the size of ping-pong balls.
As of early Tuesday afternoon, Environment Canada issued severe thunderstorm watches for large swathes of southern Ontario, including º£½ÇÉçÇø¹ÙÍøand the GTA.
Supercell thunderstorms are uncommon, often severe and long-lasting storms that feature a persistent, rotating updraft. “The risk of tornadoes is also present with some of the storms,” said Geoff Coulson, a warning preparedness meteorologist with Environment Canada.
“It does look to be the most significant potential severe thunderstorm occurrence so far this spring.”Â
Burying electrical wiring is more common in dense urban areas such as Toronto, but that doesn’t mean they’re immune to weather-related outages.Â
Burying electrical wiring is more common in dense urban areas such as Toronto, but that doesn’t mean they’re immune to weather-related outages.Â
Where and when are thunderstorms expected?
Preliminary indicators suggest large swathes of southern and eastern Ontario are at risk, said Rachel Modestino, a meteorologist with the Weather Network. These include “anywhere from Windsor all the way up through the GTA and north towards Huron counties and folks off of Georgian Bay — so the Barrie region as well,” she said. Regions near Ottawa may also be affected.
Within the GTA, the largest risk of storms are expected between the hours of around 2 p.m. to 9 p.m. Tuesday, Coulson added. is forecasting a 70 per cent risk of thunderstorms in º£½ÇÉçÇø¹ÙÍøTuesday afternoon.
“There will be bursts of rain. Some areas could get local amounts here and there of 10 to 20 millimetres,” said Coulson.
It’s expected to be a one-day storm for now. Modestino notes there is still much uncertainty around which regions will be hit and how severe the thunderstorm will be. The meteorologists are also unsure how much precipitation to expect.
“We could see a number of severe thunderstorm — and maybe even tornado — watches being issued for parts of southern and eastern Ontario once the forecasters have a better sense of which areas are most at risk” on Tuesday morning, Coulson said.
The tunnels aim to protect water quality in Toronto’s waterways against combined sewer overflow but will “significantly reduce” the number of
The tunnels aim to protect water quality in Toronto’s waterways against combined sewer overflow but will “significantly reduce” the number of
Will there be flooding or power outages?
º£½ÇÉçÇø¹ÙÍø“won’t see much flood potential” on Tuesday, Modestino said, because fierce winds are expected to blow the storms systems through the region quickly. This will limit the amount of precipitation allowed to build up.
The real dangers to look out for, according to Modestino and Coulson, are extreme winds, large hail and possible tornadoes that may occur across southern Ontario, including the GTA.Â
The numerous supercell thunderstorms formed throughout the day will likely merge together into one large storm system toward the late afternoon and evening, Modestino added.
“When that happens, we’ll be seeing those 100-plus km/h wind gusts causing power outages and all other kinds of hazards,” she said. “That’s when we get much higher risks for wind damage.”
Earlier in April, a fierce freezing rain storm left hundreds of thousands in southern Ontario without power for days. Those same regions are expected to be embroiled in the coming thunderstorm.
Why are severe thunderstorms being predicted in Ontario?
A number of “ingredients” are coming together to produce Tuesday’s storm.
The main culprit is a “very moist and unstable air mass” blowing in from the U.S., according to Modestino. This “hot and sticky” mass will cause temperatures to surge toward 30C in parts of southern Ontario, including Windsor and Sarnia, she said.
º£½ÇÉçÇø¹ÙÍøis expected to hit 23 C; taking in to account the humidity, it will feel more like 28 C, Coulson said.
At the same time, a strong cold front is expected to move across the province in the afternoon, providing a lifting mechanism to channel that moisture high into the atmosphere, said Coulson. These conditions are expected to destabilize the atmosphere and spark supercell storms across the province.
Once the cold front passes late Tuesday, temperatures are expected to go back down for the rest of the week, Coulson said. Temperatures for the rest of the work week are expected to hover around 13 C, according to Environment Canada, with potential showers on Thursday and Friday. It will likely be sunny on Wednesday.
How can I prepare for the storm?
Coulson warns Ontarians to secure any loose objects around their property before the storm hits, because strong winds could pick them up and hurl them about as projectiles: “Either bring them into the garage, into the home or tie them down,” he said.
Avoid unnecessary travel when it’s storming out. And if you hear thunder near you, find solid shelter and stay inside for at least 30 minutes after the last rumble of thunder.
“Lightning can occur all around the storm, up to about 15 to 17 kilometres away,” Coulson said. “So even when the storm has moved away from your location, you want to wait that extra 30 minutes to make sure it’s well away.”
Otherwise, Coulson recommends Ontarians to stay alert for severe weather notices, pay attention to their weather apps and keep updated with media coverage as the storm approaches.
“This has the potential for one of the more damaging outbreaks of storms that we’ve seen.”
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