Friday, July 23rd 2021, 9:14 pm - Make sure your plans include indoor activities as a backup Saturday, thanks to a forthcoming cold front will sweep through the Great Lakes region. The timing of the front still isn't 100 per cent, but is still expected to generate heavy rain and thunderstorms.
Though the last few days have been relatively benign stormwise, with very comfortable temperatures, the weekend will take a different turn, starting with Saturday. Forecasters are keeping a close eye on a system that threatens to bring severe thunderstorms to pockets of southern Ontario that day, with a fair bit of severe risk, with more change for Sunday as well in some areas. Below is a look at what we know for the weekend so far.
WEEKEND: A THREAT FOR STORMS, BUT TIMING IS EVERYTHING
Saturday is when more widespread thunderstorm risk returns to southern Ontario, after a relatively benign couple of days.
A cold front situated in northern Ontario will continue pushing through the Great Lakes region Saturday. An abundance of upper-level energy will arrive ahead of the front, bringing a widespread storm threat to much of the south.
The primary hazard for all storms will be torrential downpours, as well as gusty winds and hail – and forecasters say there is also a conditional threat for some rotating storms, with the greatest threat near the Huron shores and across southwestern Ontario in the afternoon and evening.
"The threat will be conditional on the timing of the system, which is still inconsistent among the models, but for now there is a non-zero risk of an isolated tornado on Saturday," Weather Network meteorologist Michael Carter says.
Very high moisture values are available, not at the surface, but right through to the mid- and upper-levels of the atmosphere, which means there is a high probability for storms to bring torrential rains from tapping into the moisture, aside from the other threats.
Exact amounts are not set in stone, but higher totals are expected in thunderstorms.
It’s a good idea to check back for the latest updates on the precise timing of the rain and storms.
Once the front passes, it won't be strong enough to wipe out the instability completely, leaving behind the risk for showers or thunderstorms Sunday along the Lake Erie shores and Niagara region as the energy remains.
NEXT WEEK: WARM AND FAIR WITH RAIN CHANCES RETURNING BY MID-WEEK
The last week of July would typically see a seasonal high of about 27°C in Toronto. Highs next week should climb into the upper 20s for the start of it, with humidex values well into the 30s during the afternoon hours.
Near seasonal or slightly below temperatures are expected for the second half of next week.
After this weekend, the next chance for widespread showers and storms will arrive with the next front around the middle of next week.
A changeable pattern is expected to dominate through early August, so we do not expect any prolonged periods of hot weather during the first half of August.
Stay with The Weather Network for the latest forecast across Ontario.