Environment Canada says severe thunderstorms are possible for Waterloo Region, Guelph and Wellington County on Tuesday afternoon and into the evening.
The weather office believes the strongest of the thunderstorms are capable of producing strong wind gusts up to 110 kilometres per hour, large hail up to two centimetres in diameter and heavy rainfall.
There is also a risk of a tornado, Environment Canada said.
“Large hail can damage property and cause injury. Strong wind gusts can toss loose objects, damage weak buildings, break branches off trees and overturn large vehicles,” the agency said.
“Heavy downpours can cause flash floods and water pooling on roads.”
The Office of the Fire Marshal and Emergency Management recommends that everyone take cover immediately if threatening weather approaches.