Toronto will get an "early taste of spring" this week with warm, wet weather in the forecast that could break temperature records.

The high on Tuesday is expected to be 14 C, while the high on Wednesday is expected to be 13 C, says Arnold Ashton, a severe weather meteorologist with Environment Canada based in Toronto.

Those high temperatures could break the record of 12.9 C set at Toronto's Pearson International Airport on Feb. 21, 1997. The last time that record was nearly topped was on Feb, 20, 2016, when temperatures there hit 12.5 C.

"Well, it's an early taste of spring, I guess you could say, with very mild air coming in from the south," Ashton told CBC Toronto on Sunday.

'It won't be raining all the time, but at times, it will be raining pretty hard. At times, it just will be a light drizzle,' says Arnold Ashton, severe weather meteorologist for Environment Canada. (David Horemans/CBC News) Environment Canada is also forecasting between 20 to 30 millimetres of rain to fall on Toronto from Monday afternoon to Wednesday afternoon.

Some areas, especially north and west of Toronto, could get up to 40 millimetres. The rain will be "significant" but it's over a three-day period, he said.

Rain, combined with melting snow, could lead to swollen waterways, including the Don and Humber rivers, because the moisture will not likely be absorbed into the ground, he said. There could be concerns about flooding.

"There will be a fair bit of runoff," he said.

Snow to dwindle to nothing

"It won't be raining all the time, but at times, it will be raining pretty hard. At times, it just will be a light drizzle. Any snow, even snowbanks, will be dwindling to nothing, I think, by mid-week."

Ashton said the warming trend has begun in Toronto already, with a high of 3 C and a low of minus 1 C forecast for Sunday. He described Sunday as a "fairly nice, fair weather" kind of day.

People take cover under umbrellas in Toronto's financial district. Mild conditions are forecast to 'build' into a significant warming period predicted on Monday, Tuesday and Wednesday. (Nathan Denette/Canadian Press) "Above normal temperatures are setting in. In fact, we're at the start of a mini-heat spell, I guess you could say, across Southern Ontario," he said.

A mix of sun and cloud on Sunday afternoon will give way to a partly cloudy Sunday night. The high on Monday is expected to be 8 C, with a low of 7 C.

While Sunday's mild conditions are forecast to "build" into the significant warming period predicted on Monday, Tuesday and Wednesday, cooler temperatures are in the forecast for Wednesday night.

On Wednesday, a low of –5 C is expected at night.

Warm air from the Gulf of Mexico, with a Bermuda high off to the east, is responsible for the mild conditions, he added.

"That sets the stage for a few days of significantly above normal conditions."