Heavy downpours, flash flooding are possible for Hamilton, Halton, Brant

Environment Canada has upgraded a public alert for parts of Southern Ontario where significant rainfall is expected.

The weather agency issued a special weather statement on Tuesday for Hamilton, Halton Region and Brant County but now says a rainfall warning is in effect.

A warning is an urgent message that severe weather is either occurring or will occur.

Officials say showers and isolated thunderstorms are expected to continue in Southern Ontario throughout Wednesday before moving out Thursday.

The storm will bring rainfall amounts of 50 to 60 millimetres. Some areas may be hit with higher amounts possibly reaching up to 75 millimetres.

The region may experience heavy downpours that can cause flash floods and water pooling on roads. If visibility is reduced while driving, the weather agency suggests you turn on your lights and maintain a safe following distance.

Environment Canada says the widespread rainfall event is due to a cold front and a moisture-laden low pressure system that will arrive from the American Mid-west.