Environment Canada alert meteorologist Steven Flisfeder told CTV News Toronto that meteorologists are monitoring multiple storms across the Midwestern United States and toward the border.
“There is a good chance they will reorganize into this storm complex that could give some pretty damaging winds in southwestern Ontario depending on the track,” he said.
Storms have the potential to become what is called the Intermediate Transmission System (MCS), which Flisfeder describes as “a large area of ​​storms that will produce harmful straight winds.”  Unlike a tornado, which is very localized and consists of rotating winds, the winds in an MCS are very strong and are directed in only one direction.
An MCS is a fast-moving system, Flisfeder added, and could have similar intensity to the deadly storm that struck central and northern Ontario in late May.
“It’s a thunderstorm, all combined into a wider area, but everything is just a storm,” he said, adding that lightning and heavy rainfall were also possible.
Flisfeder said the models currently show that the storm is not hitting further north than the London area, which means that the Greater Toronto and Hamilton area is likely to break, although he notes that it is not “impossible”.
As of Monday afternoon, meteorologists say the storm is likely to hit around 8pm and last through the night, but experts also say monitoring a fast-moving system like this is difficult.
“Unfortunately, it is waiting and monitoring, and as meteorologists become more confident about the direction and intensity of this storm, they will probably issue strong storm clocks.”
Filsfeder urges residents of southwestern Ontario to pay close attention to these clocks and the warnings issued by Environment Canada.
There is a 40 percent chance of rain in Toronto on Tuesday afternoon.  However, after that, the rest of the day is forecast to be sunny, with the temperature reaching 28 C with humidex.