An area of low pressure is expected to develop over the American Midwest on Saturday and bring unsettled weather to southern Ontario, southern Quebec, and eventually Atlantic Canada.
On Sunday morning southwestern Ontario may see snow that will quickly change to rain. The snow will spread north encompassing areas north of London. By Sunday night areas just west of Lake Ontario, including the GTA, will likely change from snow to rain. Some areas, particularly north of Peterborough could see up to 15 centimetres of snow. There is a risk of freezing rain. Conditions will clear by Monday morning. Southwestern Ontario and areas on the Niagara Peninsula could see up to 30 millimetres of rain.
By Sunday afternoon we may see snow in southern Quebec. Areas south of the St. Lawrence River will likely transition to rain whereas area north could remain as snow. Areas just north of the St. Lawrence River could see as much as 20 centimetres of snow. Areas south of the St. Lawrence River could see 10 to 20 millimetres of rain. There is a risk of freezing rain. Conditions clear on Monday night.
Early on Monday morning rain will push into the Maritimes and will likely remain as rain for much of the day. By the evening rain will mix with snow over Prince Edward Island and Nova Scotia and may change to snow in New Brunswick before conditions improve on Tuesday evening. In the heaviest rain, 30 to 50 mm is possible.
Newfoundland and Labrador
Snow will push across southern Labrador on Monday afternoon. Rain will make it to Newfoundland early on Tuesday. In Newfoundland, precipitation will remain as rain until conditions improve on Tuesday night. As the low pulls away, snow squalls may develop along the west coast on Tuesday night. Heavy rain is likely along the south coast of Newfoundland with the potential of 30 to 50 mm.
This low has yet to develop, keep checking back for updates.