Messy weather week ahead for Montreal with some snow

The first true winter weather of the season is upon us this week, with a series of low pressure systems and progressively colder air for southern Quebec. The first threat will arrive early Tuesday morning as rain falls across the region. Some locations, especially in the Ottawa Valley and north of Montreal will be cold enough for freezing rain and even snow. Prepare for the onset of winter travel conditions this week.

Freezing Rain Warning issued for Montreal and Ottawa for Tuesday.

Winter Weather Advisory for parts of upstate New York and northern Vermont.

As expected, slightly colder air has returned to southern Quebec after our very warm fall. The result was a brisk weekend, with temperatures in the lower single digits and overnight lows below freezing. The outdoors felt quite a bit colder, with west winds gusting over 60km/h at times.

Monday will be the calm before the stormy weather as an active weather patter is upon us. We can expect partly cloudy skies, stiff winds and highs near 5C (41F). Our weather will begin to change this evening and for the duration of the forecast period. Clouds will increase tonight, with lows of -2C (29F). 

On Tuesday, strengthening low pressure will lift across the Ohio Valley, passing to the northwest of Montreal. A warm front will approach the St. Lawrence Valley Tuesday morning, accompanied by rain and freezing rain. Depending on the surface temperatures at your location when the precipitation begins, a few hour of freezing rain will be possible. My thinking at this time is that the greatest threat will be across the Ottawa Valley as well as north of Montreal. Some regions may even start out with a period of snow, perhaps as much as 5-10cm in the Laurentians and upper Ottawa Valley.

Southerly winds will push the temperature well above freezing in Montreal, to 7C (45F) Tuesday afternoon, with any leftover precipitation falling in the liquid form. If you have any travel plans early Tuesday morning, be prepared for winter driving conditions and icy roads in spots.

First Snowfall?

A trailing cold front later in the day will usher back in more seasonable air, with high temperatures very close to the freezing point for the balance of the work week and beyond. Overnight lows will also turn colder, well-below freezing. There will be the threat for additional snowfall in Montreal as we end November, especially late Thursday and Friday when a coastal storm passes to our south. The exact track of that storm as it evolves will determine how much snow, if any, our region receives, but the potential is there for measurable snow.