Rainfall warning in effect for Waterloo region, Guelph and Wellington County with up to 50 mm possible

A rainfall warning is in effect for Waterloo region, Guelph and Wellington County with up to 50 mm possible Tuesday into Wednesday, Environment and Climate Change Canada says.

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Rain is expected to begin late Tuesday afternoon and go through the evening and overnight hours "as a moisture laden system" moves through the area, tapering off Wednesday morning.

"The showers are expected to become more widespread and heavy at times [Tuesday night] along with the risk for thunderstorms as a more unstable air mass moves in," the rainfall warning said.

"Showers will continue into Wednesday morning but are expected to become more isolated and ease off in intensity," the warning said. "Some areas may potentially be receiving in excess of 50 mm but there still remains a high degree of uncertainty."

The weather agency says heavy downpours can cause flash floods and water to pool on roads and sidewalks. Localized flooding is possible in low-lying areas and people should keep a watch out for alerts from the Grand River Conservation Authority.