WATERLOO -- A severe thunderstorm watch has been issued by Environment Canada for Waterloo Region and Wellington County.

The agency says conditions are favourable for severe thunderstorms and flash flooding Sunday afternoon and into the evening.

Heavy downpours are considered the main concern, while storms may also produce hail up to three centimetres in diameter.

It is recommended that residents take cover if they see severe weather approaching.

The agency describes the weather pattern as developing near Sarnia, remaining north of London, and heading northeast through the afternoon.