Stormy weather pattern in place through the end of November

A clipper type low pressure system from western Canada delivered the first snowfall of the season for many portions of Ontario and Quebec on Sunday and Monday. Above, several centimetres of snow fell overnight in Saint-Jérôme, Quebec. (MeteoMedia Photo)

A series of storms are progressing across the country to start the week, delivering heavy rains, strong winds and snow to many regions. Starting here in southern Quebec, an Alberta Clipper delivered the first snow of the season for many late Sunday and into the wee hours Monday morning. Wet snow fell in portions of the Ottawa Valley as well as north of Montreal through the lower Laurentians. Several centimetres accumulated in places like Saint-Jérôme overnight. The air was just too warm in the St. Lawrence Valley for snow, however close to 8mm of rain did fall overnight at my home on Ile Perrot.

As colder air moves across the warmer waters of the Great Lakes, bands of heavy lake effect snow are expected to develop downwind across parts of Ontario Monday. Snow Squall warnings have been issued for Perth and Huron Counties, but some snow will extend outside the warning areas as well. A few flurries are still possible in Montreal on Monday, with a high of 5C (41F) forecast. More wintry weather is likely by late Tuesday and Wednesday in Quebec, with the chance for mixed precipitation before warmer air arrives briefly on Thursday.

As todays system slides off to the northeast, multiple fronts and areas of low pressure will arrive every other day in Montreal, bringing an unsettled mix of rain and snow to the region. By Friday a strong cold front will arrive accompanied by heavier precipitation and gusty winds. The unsettled and stormy weather pattern will persist right through the end of the month. I am seeing the potential for a big storm system on or about November 25, but as always, the devil is in the details, so stay tuned.

Torrential rain, widespread flooding and mudslides have closed several major highways across southwestern sections of British Columbia including the Coquihalla shown above. Over 100mm of rain fell in the Fraser Valley Sunday, with more forecast Monday. (B.C. Transportation)

Meanwhile a strong Pacific storm produced torrential rain on Sunday across coastal B.C. and into interior sections. The rain, in some cases over 100mm, has produced widespread flooding. Numerous highways are closed due to mudslides and flooding including the Trans Canada and the Coquihalla from Merritt to Hope. According to B.C. Transportation, both Highways 1 and 5 have been breached in several locations, and no estimate can be given as to when the routes may be reopened. First responders are working to free many motorists who are now trapped on the closed roads.

The City of Merritt has declared a state of emergency, with several evacuations ordered. Flood warnings have been posted due to the combination of heavy rain and melting snow. Numerous rivers are at or have exceeded flood stage across southwestern British Columbia.

As the storm lifts across the Rockies, heavy snow and fierce winds gusting over 100km/h are forecast for portions of Alberta and Saskatchewan through Tuesday. The heaviest snow will be across central regions, with the strongest winds along and south of the Trans Canada Highway.