Residents of southern Ontario and parts of Quebec are in for a wet and windy Labour Day long weekend, courtesy of the Ernesto storm system.

Ernesto is expected to weaken to a tropical depression sometime Friday, but the centre of what remains will move into the lower Great Lakes on Saturday, said CBC News meteorologist Natasha Ramsahai.

The storm will bring 20 to 40 millimetres of rain and winds out of the east gusting to 50 to 60 kilometres an hour to an area stretching from Windsor to Montreal and as far north as Parry Sound.

Some areas will get even more rain and there could be localized flooding. It will also be cool, with maximum temperatures of 20 degrees or less.

Sunday will continue to be cloudy and wet, with five to 15 millimetres of rain. Although winds will ease in southern Ontario, the storm system will push eastward to Quebec City, bringing wind gusts of 40 to 50 kilometres an hour to southern Quebec.

Monday will continue unsettled, with a chance of showers and possibly some sunny periods.