Friday, December 20, 2013

Major freezing rain event for southern Quebec

This storm will not be as bad as 1998, but the same region from Ontario across southern Quebec to northern Maine will be the focus for lots of ice & snow this weekend, a very similar pattern to that of  98.
We have a very busy Friday morning in the weather department with a complicated forecast combined with one of the busiest shopping/travel periods of the year. A strong arctic boundary lays draped across the international border this morning with Montreal at -7C  (19F) while Burlington, Vermont is at 0C (32F). There in a nutshell is where the problem lies coming up with an accurate forecast. The first of three low pressure areas is moving along that boundary this morning with 5-10cm of snow likely for the St. Lawrence Valley. Freezing rain with this first storm is occurring in southern Ontario and along the US border where warnings are in place.

Temperatures will rise to or above freezing out of the valleys with colder air remaining trapped below 1000 feet and so Montreal will remain cold, around -5C most of the day. By Saturday the next low pressure area will approach from the southern US with a wide area of deep moisture. This system has the potential to produce a significant ice storm across far northern New York and Vermont and the St. Lawrence Valley including Montreal. There could be up to 15mm of freezing rain on Sunday, enough to bring down some trees and perhaps disrupt travel and power.

This is a very dangerous weather event affecting a large region of Ontario, Quebec and northern New England. I will issue another update later today. Currently warnings for freezing rain are in effect for the regions between Montreal and the US border for today. A winter storm watch is in effect for New York and Vermont for Saturday and I expect more watches or warnings will be issued later today for Montreal.

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