Steady rain and warmer temperatures are in the forecast for the GTA this week, but that could mean potential flooding in some areas.

With the temperature hovering at around 4 C Monday evening, light rain and fog draped Toronto – the start of what is expected to be a wet week in the region.  

“Several rounds of rain are forecast beginning this evening,” Environment Canada said in a special weather statement for the GTA issued Monday. “Rainfall amounts of 10 to 20 mm are likely by Tuesday morning.”

The statement is in effect for Toronto, as well as the regions of York, Peel, Halton, and Durham.

“A warm front associated with a low pressure area will move through the region tonight, bringing a significant amount of rain with it,” the national weather agency said in its advisory.

While the rain alone is not expected to be overwhelming in Toronto, Environment Canada said melting snow could add to the overall volume of water on the ground.

“This is below Environment Canada's criterion for (a) rainfall warning when the ground is frozen, however, this rainfall along with rapidly melting snow due to very mild temperatures may be enough to result in ponding of water in poorly drained areas,” the weather advisory continued.

Toronto is set to see an overnight high of 6 C on Monday but the temperature is expected to rise to a high of 15 C on Tuesday and 11 C on Wednesday.

Between five and 10 millimetres of rain are expected to fall in Toronto on Tuesday and more showers are in the forecast on Wednesday.

The conditions have prompted the Toronto and Region Conservation Authority to issue its own advisory forecasting between 25 and 40 milimetres of rain for the Toronto area from today Through Thursday morning.

“Snowmelt caused by the warmer temperatures, in combination with the forecast rainfall will result in a high volume of runoff and increased water levels in rivers and streams in TRCA's jurisdiction,” the statement said. “In addition, many of our rivers and streams are still covered in ice, and ice break-up is expected to occur on Monday through Thursday.”

The organization said localized flooding could be the result over the next few days.

“Because we have watersheds that are very small, very short, because we have a lot of paved areas, it doesn't take very long for that water to concentrate in our rivers and streams,” TRCA spokesperson Rehana Rajabala told CTV News Toronto. “The problem is that when that rain comes it also brings with it the potential to melt that snow. So we've got warm temperatures, we've got that rainfall and that rainfall is going to bring all of that snowpack down with it.”

Rajabala said it's important to keep children and pets well away from rivers and streams over the next few days.

While Toronto sits under a special weather statement, much of southern Ontario is under a more severe rainfall warning. Those areas include Caledon, Uxbridge, Beaverton, and  Northern Durham Region. Multi-day rainfall totals are expected to reach from 30 to 50 milimetres in those areas.

More seasonal temperatures are expected to return to the province on Thursday, with a high of 1 C and a low of -4 C in the forecast.