Prepare for a rain-soaked day in the GTA

It's going to be a wet day in the GTA, Environment Canada says.

Heavy rain is expected to fall on the region until about 10 a.m. Friday,when it will gradually taper off into lighter showers, the national weather agency forecasts.

The dreary conditions are set to stick around throughout the day, with between 25 and 40 millimetres of rain possible by this evening.

Toronto and Region Conservation Authority is advising residents to be cautious around bodies of water.

"The combination of slippery and unstable banks could create hazardous conditions close to any river, stream or other water bodies. All shorelines, rivers and streams within the GTA should be considered hazardous," TRCAsaid in a statement issued late Thursday.

Flurries are also possible overnightas the mercury drops to the freezing mark in the early morning hours on Saturday before clearing around noon. Rain is forecast toreturn on Sunday.

More rain for cottage country

To the north, Environment Canada has issued rainfall warnings for large swaths of cottage country, including in the Parry Sound Muskoka region.

The towns of Bracebridge and Huntsville have been dealing with severe flooding in recent days.

Bracebridge Mayor Graydon Smith said Thursday thata pair of lakes north of the communitydon't have the capacity to contain any more water.Fairy Lake and Mary Lake, which drain into the river that runs through Bracebridge, are "stressed" already and more rain could be a significant "jolt" to the system, he explained.

Officials in eastern Ontario are also warning that water levels on the Ottawa River could reach levels last seen during the floods of 2017.

Michael Sarich, senior water resources engineer with the Ottawa River Regulation Secretariat, says levels have been "sharply increasing" over the last week.

"Snowmelt runoff and recent precipitation have led to a forecast that indicates we're going to be meeting at least levels that were experienced back in 2017, which was the flood of record," Sarich said.

"In 2017, levels and flows reached unprecedented historic levels, pretty well for most of the length of the Ottawa River. So there was significant damage: large sectors of some municipalities were affected and low-lying areas were significantly flooded."

Sarich added that the impact on people in the area could be "catastrophic," but noted that the region is much better prepared this time around.