Saturday, June 6th 2020, 8:28 am - Cooler air has filtered into Ontario after the front passed, but lingering instability could trigger more thunderstorms Saturday, possibly severe in eastern areas
Saturday will mark the beginning of a temporary cooldown in southern Ontario after a front triggered severe thunderstorms in parts of the region Friday. While temperatures have dropped, leftover instability could spark off more thunderstorms, though the potential for stronger cells will remain in the east, where they could turn severe. An isolated storm is possible in parts of the south, but the risk decreases west of Toronto. Sunday will be cooler still, but the heat and humidity return mid next week. We have more details below.
- Cooler, fresher air moves in, with lingering instability Saturday
- Chance of severe storms in eastern Ontario Saturday
- Hot and humid again mid next week
- Keep on top of active weather ALERTS here.
SATURDAY: COOLER, BUT LINGERING INSTABILITY COULD SPARK STORMS
While the front did in usher in cooler air for Saturday, dropping temperatures to the low- to mid-20s across most of the south, lingering instability could fire up more thunderstorms in the afternoon.
Eastern Ontario is where the highest threat will be, with the chance of some storms turning severe, but isolated cells are possible in the south. However, the potential decreases west of Toronto for isolated, non-severe thunderstorms. Most of the region won't see any rain.
The main threats with the stronger storms in the east will be heavy rain, small hail and strong winds.
SUNDAY: PLEASANT CONDITIONS, WITH COOLER TEMPERATURES
Sunday will be much more pleasant as any remaining instability will be gone, leaving nothing but mostly sunny skies behind. Temperatures will drop off again, with daytime highs even cooler than Saturday's. Most of the south will just barely reach the 20s or even remain in the upper-teens.
BEYOND: COOL BUT FAIR START TO THE WEEK
Monday looks sunny and a few degrees warmer, and temperatures and humidity spike again for Tuesday and Wednesday, with daytime highs in the upper 20s and lower 30s.
"Some models have a few spots reaching the mid 30s, but we will keep the forecast conservative for now due to uncertainty as to how Tropical Storm Christobal will influence the overall pattern," Weather Network meteorologist Dr. Doug Gillham says. "The humidex could approach 40 on Wednesday."
A cold front will track across the region Wednesday night and Thursday, with a period of rain and thunderstorms, bringing an end to the brief heat wave. The weekend beyond looks to be 'much cooler,' Gillham says.
Check back as we continue to monitor the forecast.