A special weather statement is in effect for Toronto today with brief but “very heavy downpours” possible this afternoon while other parts of the GTA could see severe thunderstorms.

Environment Canada says local rainfall amounts of between 20 and 40 mm are possible in an hour or less along with strong wind gusts.

“Isolated thunderstorms moving slowly across the region this afternoon will contain brief very heavy downpours,” the national weather agency warned in its advisory.

“Sudden very low visibility and ponding of water on poorly drained areas of highways from the downpours may result in difficult driving conditions.”

West of the city, a severe thunderstorm warning is in effect for parts of Halton and Peel regions --  including Burlington and Oakville – as well as Hamilton.

As much as 50 milimetres of rain could fall within an hour in those areas, Environment Canada said.

Special weather statements are currently in effect for most of southern Ontario because of the expected rainfall.

The inclement weather is expected to end this evening.