11AM Update: Locally heavy snow prompted a late snowfall warning from Environment Canada this morning for Montreal. The heaviest snow is now off to the east of the city, with just a little light snow left before precipitation ends early this afternoon. The warning should expire shortly. Montreal will be left with between 10 and 15cm of fresh powder. More snow is forecast by Thursday.
Previous Post: Clipper systems are notorious for over preforming when it comes to snowfall amounts. They are usually moisture starved, originating from the Prairies, but can receive new life from the Great Lakes, especially when the lakes are ice free like this year.
I noticed last evening that heavy snow was falling in Toronto around 7pm and wondered if it would make it into Montreal for the morning commute. It did, I should have updated my forecast then. The morning commute is a mess in metro Montreal, with snow covered roads and long delays to get onto the island of Montreal. The 10 to 15cm expected today, is falling on top of the 34cm that fell Friday. Only 25% of Friday's storm has been trucked off the roads in Montreal. That leaves plenty of narrow, snow choked avenues to navigate, with very little parking.
The low pressure in question will move down the St. Lawrence Valley quickly today, replaced by weak high pressure for Tuesday. Expect snow to taper off to flurries this afternoon. Close to 10cm has fallen already at Trudeau Airport, with another 5cm before it ends. Temperatures will be mild today, up to -1C for a high. Another winter storm is possible for Thursday, followed by a surge of arctic air to end the week.