Massive winter storm to impact Ontario and Quebec

This weekends storm produced more snow that originally forecast for the Montreal region, as the system moved slightly further north. Traffic was slow on Highway 20 in Ile Perrot, with roads remaining snow covered for most of the day.

Widespread high wind watches, winter storm watches and special weather statements are in effect across Ontario, Quebec, New York and New England for late Tuesday and Wednesday.

We have a very active weather week ahead as two powerful low pressure systems moving across the eastern portion of North America. Before we cover that, let's close up this past weekends snowstorm. The system definitely over performed here in the St. Lawrence Valley. The snow started late Saturday afternoon, lasting 24 hours in the Montreal region. I measured 19cm on Ile Perrot, officially 15 to 20cm fell across the greater Montreal region according to a statement form Environment Canada. Gusty winds produced blowing snow and made roads rather slick on Sunday. There were numerous accidents reported.

The active weather will continue this week. High pressure will briefly build into southern Quebec on Monday, with party sunny skies and seasonable highs near -4C (25F). Skies will fair overnight, with lows near -12C (10F). On Tuesday clouds will thicken and lower ahead a warm front and strong low pressure system forecast to move from the lower Mississippi Valley towards the Great Lakes. The storm is expected to deepen rapidly to a major storm and pass just north of Montreal on Wednesday. 

A wide swath of impactful weather is expected for the eastern two thirds of North America. There are already numerous weather watches and warnings in effect. For Montreal, snow will develop late Tuesday and gradually change to freezing rain and eventually rain on Wednesday morning. Significant amounts of precipitation are expected. Further north, a swath of heavy snow is forecast, with accumulations exceeding 30cm. Accompanying the precipitation will be strong to severe winds across a large portion of the region. Wind gusts between 60-100km/h are expected for many locations. Winds this strong combined with heavy precipitation will likely produce power outages. Precipitation will change back to snow late Wednesday before ending overnight. Temperatures will rise above freezing Wednesday to 3C (38F) before dropping back below freezing into Thursday morning.

This storm has the potential to cause major disruptions to travel, both n the ground and in the air, as well as widespread power outages. 

Further south across the Gulf States and into Florida, strong to severe thunderstorms and numerous tornadoes are expected. Many parts of the eastern US and Atlantic Canada may see significant flooding from heavy rain and melting snow.

Once we clear this storm out on Thursday, an equally strong system will follow for late Friday and Saturday. More on that later.