Residents in southern Ontario are in for more stormy weather today after heavy rain and high winds -- along with reports of tornadoes -- battered the region Sunday.

Environment Canada said Monday morning that a cold front will approach southern Ontario tonight.

Ahead of the front, one or two bands of thunderstorms are forecast to develop and there is a "slight risk" that they could become severe.

The weather agency defines a severe thunderstorm as having one or more of the following:

• tornadoes
• wind gusts of 90 km/h or greater
• hail of 2 centimetres diameter or greater
• rainfall rate greater than 50 millimetres in 1 hour or less or 75 millimetres in 3 hours or less

On Sunday evening, Environment Canada issued tornado warnings for parts of southern Ontario and western New Brunswick.

Watch MyNews video of the storm (WARNING: strong language)

There were reports of tornadoes -- or just funnel clouds -- near Lucan, north of London and in (Sombra) in Lambton County, and (near Burgessville) Oxford County.

Investigators for Environment Canada are heading out to the region Monday to inspect damages to determine if a tornado actually touched down.

Environment Canada's Geoff Coulson told The Canadian Press that satellite images showed a "classic tornado-shape'' in the area north of London.

Meanwhile, some residents in the Dresden area will be cleaning up Monday after reports emerged of roofs being torn off buildings and trees being uprooted.

Across the region, people had to also deal with flying debris and downed power lines.

Also Sunday, lighting temporarily cut power to hundreds of homes in the Waterloo region.

Elsewhere in the country, Woodstock and Carleton County, N.B. residents were told to stay on alert and take safety precautions as heavy rains and strong winds hit the region.

There are no reports of any damage in the wake of Sunday's tornado warning.

A heat wave in Central Canada is blamed for the severe weather in parts of Ontario.

Environment Canada expects this summer to be unusually warm and warn with the heat come storms.

Torrential rains, baseball-sized hail, high winds and tornadoes have also slammed the American Midwest, killing three people.

Violent weather has plagued parts of Indiana, Minnesota, Wisconsin, Illinois, Oklahoma, Nebraska and Michigan since early Friday, leaving a path of destruction in its wake.

With files from The Canadian Press