Environment Canada says Waterloo Region, Guelph and Wellington County could be in for severe weather Friday afternoon and into the evening.
The weather office says the area is expected to get hit with severe storms with damaging wind gusts and there is a chance a tornado may form in northern Wellington County.
“There is the potential for tornadoes late this afternoon or early this evening as severe thunderstorms develop over portions of the regions ahead of a strong cold front,” the weather office said.
Thunderstorms from Michigan will reach western portions of southern Ontario by the late afternoon and then move rapidly eastward across the regions, the agency said.
Some of the more specific hazards include heavy rain, wind gusts of 90 km/h, lightning, poor visibility and water ponding on the roads. There could also be some hail.
Environment Canada said strong wind gusts can often toss loose objects, damage weak buildings, break branches off trees and even overturn large vehicles.
It asked residents to monitor alerts and forecasts.