Severe thunderstorms could bring heavy rain, hail, but probably not tornadoes to the St. Albert region this afternoon, Environment Canada says.
Environment Canada issued a severe thunderstorm watch for the Edmonton, St. Albert, and Sherwood Park region at 2:28 p.m. July 24.
Environment Canada issues severe thunderstorm watches when conditions are right for thunderstorms with winds of at least 90 km/h (which can damage buildings), hail at least two centimetres wide, and heavy rains of at least 50 mm in an hour. Those watches become warnings whenever a storm with any of those traits actually happens.
Brian Proctor, an Environment Canada meteorologist based in Edmonton, said this severe weather watch was brought about by the recent breakup of that high pressure system that had brought clear skies to this region for much of the last few weeks.
“A lot of the cloud cover and smoke we are seeing out there is starting to really thin out,” he said, and that’s letting the sun warm the Earth’s surface.
As this happen, moist air rises to form towering, thunderous cumulonimbus clouds, Proctor continued. These clouds are being sent spinning by a jet of fast-moving air now over Alberta, which lets them develop more rain, bigger hail, more intense lightning, and, potentially, tornadoes.
“The potential is out there in a few locations for tornadoes,” Proctor said, although those were more of a risk in the Olds to Red Deer region — Edmonton should just get a big storm.
Proctor said the Edmonton region could see quarter-sized hail and dumps of up to 10 mm of rain should a thunderstorm roll in today.
Thunderstorm conditions were expected to last all night, Proctor said. He advised residents to watch the skies and keep an ear out for thunderstorm warnings issued by Environment Canada. Should a thunderstorm be spotted, residents should immediately head indoors to avoid injury from hail, lightning, falling trees, and other hazards.
“The safest place to be is indoors,” he said.
Proctor said thunderstorms were reasonably common around Edmonton in July and August and particularly when high pressure systems broke up.
Visit weather.gc.ca for a list of current weather alerts.
