--- Update ---

The rainfall forecast has been updated to reflect the changing track of the storm. Now 20-40 mm of rain is expected to fall, up from the original 15-30 mm forecasters predicted earlier Sunday morning.

--- Original Story ---

A severe thunderstorm watch has been issued for the region.

Environment Canada says conditions are favourable for the development of severe thunderstorms that may be capable of producing heavy rain.

Severe thunderstorms may move in from Northern Minnesota later this morning.

The primary threat is nickel-sized hail. There is a lesser threat of damaging wind gusts.

Heavy downpours can cause flash floods and water pooling on roads.

The forecast for today is calling for 10 to 20 mm of rain with an additional 10 to 20 mm overnight.

Yesterday a special weather statement was issued, warning residents that upwards of 80 mm of rain could fall between two storm systems that will begin hitting the region today and departing on Tuesday.

Severe thunderstorm watches are issued when atmospheric conditions are favourable for the development of thunderstorms that could produce one or more of the following: large hail, damaging winds, torrential rainfall.