The first "significant snowfall" of the season could bury Ottawa with up to 20 centimetres of snow by the time residents wake up on Monday.
A "snowfall warning" remains in effect for the Ottawa-Gatineau area.
"Snow, at times heavy, is forecast to begin (Sunday) afternoon. Snowfall amounts of 15 to 20 centimetres are expected by the time the snow tapers off Monday morning," said Environment Canada in a statement calling for "significant snowfall."
"This heavy snow is due to a strengthening low pressure system that will track northeastward across the lower Great Lakes"
In an interview with CTV News Ottawa, Environment Canada meteorologist Yoseph Mengesha said driving, walking and cycling conditions will be poor Sunday evening and on Monday.
"It will start out with light snow (Sunday) afternoon and continue into the overnight. The total amount will be 15 to 20."
Mengesha says the snow will be heaviest Sunday evening, and then taper off Monday morning.
The meteorologist says the weather system originated in Colorado, and the Colorado low has been making its way through Ontario all day.
"Since we are getting close to the holidays, it seems kinda nice," said one resident out on Sunday afternoon. "I'm looking forward to it. The shovels and everything else is ready to go."
Another person told CTV News Ottawa on Sunday, "I like snow around this time of year. I feel like it kinda covers up a bit of the grunginess once the leaves have fallen."
The record for greatest snowfall on Nov. 22 in Ottawa history is 14.4 centimetres, set back in 2007. This would be the second snowfall in November in Ottawa. On Nov. 2, Ottawa received 3.7 centimetres of snow.
The snowfall warning is also in effect for Renfrew, Pembroke and Barry's Bay, Smiths Falls, Lanark and Sharbot Lake.
A weather advisory has been issued for Brockville, Leeds, Grenville and Kingston areas, calling for seven to 14 centimetres of snow and poor visibility.
Here is a look at the Environment Canada forecast for Ottawa.
Tonight: Snow at times heavy. Risk of freezing rain overnight. Snowfall amount15 cm. Low minus 2C with the temperature rising to 0C by morning.
Monday: Periods of snow ending in the morning then mainly cloudy. Amount 2 cm. High plus 2C.
Tuesday: Sunny. High minus 4C
Wednesday: Snow. High plus 1C
The normal temperatures for this time of year are a high of 3C and a low of minus 5C