Another oh-so-brief stretch of warm, springlike Toronto weather is expected to end abruptly tonight with the potential arrival of a "cluster of organized thunderstorms."

According to The Weather Network, Southern Ontario could be subject to the tail end of a mesoscale convective system (MCS) that has been gathering strength across the U.S. Midwest all day.

It's not quite clear how far north into Ontario the storm system will come, but the heat wave trailing behind it will almost certainly have Toronto residents seeking out fans, shade, pools, popsicles and A/C come Thursday.

"The MCS is a conditional threat that depends on the timing of a disturbance as it rounds the ridge of high pressure responsible for extreme heat across much of the continental U.S.," notes The Weather Network.

"If the MCS does impact the region, there could be rain and severe storms in areas near the U.S. border and along the western Lake Erie shores into the pre-dawn hours Tuesday morning... Additionally, a building heat wave south of the border will begin to influence our weather this week."

Check out the humidex forecast for Thursday, and then join me in mourning all the good hair days that might have been. pic.twitter.com/8lOrRXvTLr

— Lauren O'Neil (@laurenonline) June 13, 2022

Even if we avoid the worst of the storm, or all of it, meteorologists say that we can expect several days of above-seasonal temperatures this week as humidity builds and rises.

For Toronto, that's looking like a "feels like" temperature of 40 C by Thursday, which is forecast to have a high of 30 C but just soooo much humidity.

Fortunately, that'll be the hottest and soupiest day this week by far; temperatures are expected to dip back down to a much more manageable 25 C (with a humidex reading of 28 C) on Friday and chill out even more for Father's Day weekend.

Both The Weather Network and Environment Canada are calling for heat-provoked thunderstorms in Toronto on Thursday, but Saturday and Sunday look nearly perfect for ending out the spring season, with highs in the early 20s and nothing but sun in the skies.