Thursday, December 19, 2013

Messy weather next several days for Montreal - Ontario

The scenario for this upcoming weekend remains messy and uncertain with a mix of snow and freezing rain forecast right into late Sunday. We start this morning with an area of light snow over Montreal, look for 1-3cm before it tapers off shortly. It will be milder today around -1C for a high. More snow will move into the region tonight as a frontal boundary lines up across northern New York and Vermont. Warm air will override that front and produce precipitation. All weekend long that front will remain in place with a very sharp temperature gradient separating arctic air in southern Quebec and the St. Lawrence Valley from much milder air working into southern New York and New England. The temperature will remain below freezing in Montreal while it rises way above in southern Vermont. Several waves of low pressure will move along that front bringing moisture from the Gulf of Mexico. The result will be about 10-20cm of snow from late tonight into Saturday morning, that is round 1.

Round 2 arrives late Saturday night in the form of a stronger low pressure area and another surge of mild air aloft along that front. That will trap the cold air at the surface in Montreal, and we could be in for a prolonged period of freezing rain by Sunday. There will be lots of people moving around this weekend with shopping and travel plans. You need to know that this will be a difficult drive all weekend. Wait until Monday if you can or expect delays and difficulty. There will no doubt be some form of watch or warning issued over the next 12 to 24 hours. I will update the blog regarding this storm as often as I can. There is also the risk of power outages with the amount of freezing rain that could fall. If you need to prepare for that in advance, gas, food etc., then do so.

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