Dangerous freezing rain event for Montreal and Ottawa

A narrow band of heavy freezing rain will set up along a frontal boundary Saturday into Sunday. Montreal has the potential to receive a significant amount of frozen precipitation. (AccuWeather.com)

Special Weather Statement: Montreal and Ottawa.
Winter Storm Watch: St. Lawrence Valley

A period of heavy freezing rain is forecast for the St. Lawrence Valley including Montreal late Saturday into Sunday.

A very dangerous weather situation is setting up for the upcoming weekend across a portion of Ontario and southern Quebec. A warm front is lifting north of Montreal Friday morning, with temperatures expected to rise rapidly today up to 5C (41F). A few flurries or spotty showers are expected today. Heavy rain changing to freezing rain is likely Saturday.

Ice Storm
On Saturday the aforementioned front will begin to settle south once again, with arctic air located just to the north and a surge of record breaking tropical air to the south or Montreal. Along the front, low pressure will lift north, accompanied by abundant moisture. Heavy rain will develop across the region, with as much as 25mm (1 inch) expected. Saturday evening, cold air is expected to bleed back into the St. Lawrence and Ottawa Valley as well as extreme northern Vermont and New York, with rain changing to freezing rain. Ice accumulations may be significant, with more than 25mm possible by Sunday morning. This amount of ice accretion will result in tree and power line damage. Expect power outages. Strong winds are also expected on Sunday, up to 70km/h in Montreal, which will only add to the damage potential. The precipitation will taper off Sunday afternoon.

The temperatures will be wild this weekend, possibly reaching a record high 10C (50F) in Montreal on Saturday. The previous record was 9.4C (49F) set in 1975. However the mercury will fall just a quickly Saturday night once the cold front slips south of Montreal, down to -7C (19F). The temperature range will be very dramatic across a very small region Saturday evening. Travel will become extremely difficult

Now is the time to plan for power outages. Charge your devices, prepare your home and make sure you have a full tank of gas. There is still some uncertainty in the path of the storm and where the freezing rain will set up. Hopefully Montreal ends up with more liquid precipitation or sleet, but at the moment, it is looking like freezing rain.

I will update the forecast and any warnings throughout the event.