CBC meteorologist Peter Coade says two weather systems — one from the northwest and another warm and moist disturbance out of the Gulf of Mexico — are forecast to collide and become one, just south of Nova Scotia on Sunday.
The system is expected to produce snow. Coade expects "all forms of traffic" to be affected on Sunday, including flights, roads and ferries.
"Although it is still early to come up with a solid snowfall amount forecast, I think it safe to say that blizzard conditions can be expected with the strong east-to-northeast wind blowing around some 10 to 20 centimetres — possibly as high as 30 to 40 centimetres — of fresh snow," said Coade.
Snow will develop in areas of southwestern Nova Scotia and southwestern New Brunswick late Saturday afternoon or evening and spread north and east Sunday to reach northern New Brunswick and Cape Breton before noon, said Coade.
Environment Canada warns of snow squalls for Nova Scotia's Antigonish and Guysborough counties, as well as P.E.I.'s Kings and Queens counties Friday morning.
"Snow squalls cause weather conditions to vary considerably, changes from clear skies to heavy snow within just a few kilometres are common. Be prepared to adjust your driving with changing road conditions," Environment Canada says.
"Snow Squall Warnings are issued when bands of snow form that produce intense accumulating snow or near zero visibilities."
As a result of snow squalls, all classes at public schools in Antigonish County were closed Friday.
The national weather service has all of the Maritimes under a special weather statement for Sunday, advising the public to monitor weather forecasts ahead of the storm.
Coade expects "all forms of traffic" to be affected on Sunday, including flights, roads and ferries.
While the weather may be wintry, the official start of spring occurs at 7:45 p.m. on March 20.