Freezing rain warning posted for southern Quebec

Have your scraper and patience ready for the Monday morning commute across southern Quebec. Plan on leaving early or even better, work from home if you can. Definitely stay home if you do not have winter tires on yet. Freezing rain and winter storm warnings are currently in effect across the region.

• Freezing rain warning in effect for metro Montreal, southern Quebec and eastern Ontario.
• Winter storm warning in effect for the Laurentians including Mont Tremblant.
• Precipitation starting in southwestern Quebec by 6pm Sunday and moving northeast across the region.
• Expect a very messy morning commute Monday, especially from Laval north and east.

Weather warnings have been issued for large portion of Ontario and Quebec for the incoming winter storm. The expected track of the system has shifted a little south over the last 24 hours, but still passing north of Montreal while strengthening. This will result in colder air hanging around in the Ottawa and St. Lawrence Valleys for a little longer, increasing the threat for more frozen precipitation.

I still feel the amounts forecast by Environment Canada Sunday morning for Montreal are a little on the high side, but it is a difficult forecast. These storms that run along or just north of the St. Lawrence Valley introduce many forecasts challenges, with a few degrees or even a few kilomteres making all the difference in a forecast.

Low pressure will move from southern Ontario on Sunday into western Quebec early Monday. A warm front will lift across the region Sunday night accompanied by a period of steady snow and a surge of warm air. Snow should change to freezing rain by the early morning hours from south to north across the island of Montreal. All precipitation will change to rain from Montreal south early Monday morning as the temperature soars to 8C (48F). Precipitation will remain messy mix north and east of the city most of the day. A strong cold front will produce heavy rain and strong winds, up to 70km/h in the afternoon, along with rapidly dropping temperatures and a likely freeze-up for Montreal during the evening hours. The temperature will bottom out at -6C (21F) by Tuesday morning.

In terms of accumulations, that will be very dependent on where you are located in the greater Montreal region. From southern portion of Montreal, such as Ile Perrot where I am located, I am thinking 5cm of snow and perhaps 2mm of freezing rain before we transition over to rain on Monday. Other regions of southern Quebec and eastern Ontario can expect 5-20cm of snow along with 2-5mm of freezing rain. Look for another 10mm of rain along the cold front for those locations that are above freezing such as Montreal.

Skies will clear out Tuesday behind the storm. Briefly looking ahead, there are two more systems at this time set to deliver more mixed wintry weather to southern Quebec by the end of the week. But first, let's deal with this storm.