In its notice, the federal agency said a Colorado low would move through the region, dumping perhaps two to four inches of snow.
Areas near Lake Ontario might see less buildup because the snow will be very wet, Environment Canada said.
Other regions of the GTA, including Peel, Halton, York and Durham, are also the subject of a special weather report.
The federal agency said Sunday’s “heavy snowfall” could affect travel, urging motorists to prepare for winter driving conditions.
“This is our first winter event of the year,” city spokesman Eric Holmes said in an interview with CP24 on Saturday night. “We plan everything. We are ready for anything. ”
Holmes said the city’s northern end is expected to see a build-up while the downtown area could see more rain than snow.
“We will have the equipment ready. It will be off. It will be snow removal. It will be icebreaking and road safety, ”he said.
“If you are not comfortable on the road and if you are not comfortable traveling, definitely stay at home. Avoid the roads. ”
Sunday high will be 2 ° C, with a wind chill of -3 in the morning.
Environment Canada said the snow will diminish overnight.
On Monday it will be a mix of sun and cloud with 40 percent chance of showers. The maximum will be 5 C.