The Toronto and Region Conservation Authority issued flood warnings covering much of the GTA on Friday as thunderstorms are expected to produce 50 millimetres of rain.
This amount of rainfall over watersheds would result in rapidly rising and fast moving water, officials said. Conditions could be dangerous around streams, rivers and all bodies of water.
Roads and low-lying areas near bodies of water could also become flooded and drivers should be cautious while driving. Environment Canada also asked motorists to turn on vehicle lights and maintain a safe distance from other cars if caught in the storm.
Isolated storms developed north of Lake Ontario on Friday afternoon, according to Environment Canada. Small hail and strong wind gusts are expected along with the thunderstorms.
There are still severe thunderstorm warning in effect for Uxbridge, Beaverton and the Northern Durham region. An earlier warning covering much of Halton Region, Vaughan, Peel Region, Newmarket, Markham, Pickering and Oshawa was cancelled Friday afternoon.
