Toronto, Environment Canada has issued a Severe Thunderstorm Watch for Toronto and much of the GTA.
The agency says dangerous thunderstorms could form later today that might bring strong wind gusts, large hail and torrential rain.
Potential storms could toss around objects, break windows and cause water levels to rise rapidly in rivers and creeks.
The Toronto Region Conservation Area issued its own advisory Saturday warning that people should make sure to keep away from waterways as water levels rise.
“Rapidly rising water, high river and stream levels, or fast moving water all create dangerous conditions,” the TRCA said in its statement. “The possibility exists for flooding on roadways and in low-lying areas.”
Thunderstorm watches have also been issued today by Environment Canada for many other parts of southern Ontario stretching from Windsor to Conrnwall with some changing rapidly to warnings.
The active weather comes amid summer-like temperatures and humid conditions in Toronto, where a high of 29 C is expected Saturday.
The rain is expected to continue in the city Sunday and Monday, with showers forecast both days. The temperature is also expected to plummet 20 degrees over that period to a high of 10 C Sunday and a high of just 12 C Monday.
However sunshine and warmer temperatures are expected to return Tuesday through Thursday.