Freezing rain warning posted for southern Quebec

Widespread freezing rain is expected tonight along the St. Lawrence Valley, with between 2-15mm of ice accretion expected. Freezing rain warnings have been issued for metro Montreal.

On this 25th anniversary of the great ice storm of 1998, we have a freezing rain warning posted for metro Montreal. We are not expecting a big storm, but travel will be tricky Thursday morning.

A messy weather system is expected to spread mixed precipitation into southern Ontario and Quebec over the next 36 hours. A warm front will move northward today very close to the international border tonight before it settles back south again. Low pressure will move along that front and spread precipitation into the region by the late afternoon in Ontario and the evening hours here in Montreal. 

At this time, we can expect a prolonged period of freezing rain in the St. Lawrence Valley. The freezing rain will begin by 9pm in Montreal, mixed with ice pellets and snow at times. Amounts of frozen precipitation will vary considerably across the region, with 2-5mm of ice accretion forecast for the island of Montreal along with up to 10cm of mixed snow and ice pellets. 

North of the city, more snow is expected, with 10-15cm. Across the southwest portion of Quebec, including Vaudreuil and Valleyfield, heavier amounts of freezing rain are expected, with as much as 10-15mm of ice accretion. That amount is certainly capable of creating difficult driving and walking conditions, as well as isolated power outages and tree damage.

Temperatures will be mild today, around 2C (36F), but cold air will begin to undercut the warm air tonight, with the mercury falling to the freezing point in Montreal and down to -4C (26F) by Thursday morning. Accompanying the precipitation will be increasing northeast winds of 30-70km/h, drawing in the colder air and allowing for the frozen precipitation.