Hazardous heat accompanies severe weather potential on the Prairies
Threatening heat builds across the Prairies as a risk for severe thunderstorms targets the region this weekend.
This weekend won't be particularly ideal for outdoor activities for many parts of the Prairies, with extreme heat, humidity and the ongoing risk for thunderstorms, which could become severe some areas. Saturday evening includes a very conditional tornado threat in parts of Alberta and Saskatchewan. A strong ridge of high pressure on Sunday provides a lot of hot, unstable storm energy across the eastern Prairies with humidex values in the 40s. More on the weekend storm threat and just how hot it’ll get, below.
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THIS WEEKEND: MULTI-DAY THUNDERSTORM THREAT AMID EXTREME HEAT
This evening and Sunday will be hot, and possibly stormy, on the Prairies thanks to the heat and humidity, as well as other ingredients in place.
Severe thunderstorms will be likely in southern Alberta and Saskatchewan as a low-pressure system advances north from Montana into southern Saskatchewan. Severe thunderstorm watches are in place in southern Alberta.
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There is a high-risk of stronger storms this evening for southeastern Alberta and southwestern Saskatchewan as a low tracks over the region and moves northeast.
With very high CAPE values and shear present within the atmosphere, dynamics are favourable for supercells Saturday in extreme southern Alberta that could track northeast into Saskatchewan, carrying the risk of a tornado into the late-evening hours, along with large hail. The tornado threat is very conditional.
By Sunday, the severe storm potential pushes farther east into southern Saskatchewan, southern Manitoba and northwestern Ontario as the low-pressure system continues to track in that direction.
The low-pressure system will ignite the severe storm potential throughout Sunday afternoon. "If storms remain isolated supercells, a couple of tornadoes would be possible near the Saskatchewan and Manitoba border late afternoon into the early evening," says Weather Network meteorologist Tyler Hamilton.
There will likely be some Sunday morning thunderstorms across Southern Saskatchewan, along with Manitoba. Residual cloud cover and morning convection could alter the Sunday afternoon risk.
The possible hazards with severe storms include strong wind gusts, large hail and heavy rain.
WIDESPREAD HEAT WARNINGS IN EFFECT SUNDAY
In addition to the thunderstorm threat Sunday, high heat and tropical humidity will spread from west to east across the southern Prairies. Daily temperature records and dangerous humidex values are likely. Just how hot and muggy? The humidex will feel like the mid-40s, which will be uncomfortable and dangerous heat for some.
Heat warnings are in effect across Saskatchewan and southern Manitoba, along with special weather statements, as a heat dome in the southern U.S. will nose the northern part of the ridge into the Prairies.
Parts of southern Manitboa and Saskatchewan will feel mid-30°C heat on Sunday. Humidex values will be into the 40s for parts of the aforementioned regions.
"Extreme heat affects everyone," says Environment and Climate Change Canada (ECCC) in the heat warning.
"The risks are greater for young children, pregnant women, older adults, people with chronic illnesses and people working or exercising outdoors. Watch for the effects of heat illness: swelling, rash, cramps, fainting, heat exhaustion, heat stroke and the worsening of some health conditions. Drink plenty of water even before you feel thirsty and stay in a cool place. Check on older family, friends and neighbours. Make sure they are cool and drinking water."
Much cooler conditions are expected next week, though remaining warmer at times for parts of Manitoba.
Thumbnail courtesy of Marjorie, taken in Kleefeld, Man.
Be sure to check back for updates this weekend as we continue to fine tune the forecast details on the storm timing and severity.