Monday, November 08, 2010

Surprise Nor'easter

A stubborn area of low pressure has been meandering around Atlantic Canada since Thursday. It had pulled far enough east to allow for sunshine yesterday, but is slowly retrograding southwest this morning. We were expecting sunshine today, but cloud cover has already moved into Montreal and precipitation is into Quebec City and the Townships. The storm is centered over the Gulf of Maine and will slide southwest towards Cape Cod. Precipitation in the form of freezing rain and some snow will fall across the Townships south into the Green Mountains. Winter Weather Advisories and Freezing Rain Warnings are in effect for those areas. If you must travel there, allow extra time or hold off until after the lunch hour. I expect that the precipitation will reach Montreal by noon and it should be in the form of rain. Winds will be increasing as well out of the north and northeast to 50km/h and as high as 70km/h in Quebec City.

This same storm has produced major flooding in Nova Scotia and southern New Brunswick. Copious amounts of rain have fallen since Thursday with 291.8 mm at Mechanic Settlement, NB, and 202 mm at Yarmouth. A state of emergency has been declared in many areas with roads washed out and homes flooded. The plume of moisture has been driven north along a frontal boundary from the tropics, and the remains of hurricane Tomas. Another 20-40mm may fall today.

As much as 15-25mm of rain may fall in the Townships with 10-15mm in Montreal. I expect the frozen precipitation will accumulate about 2-5mm of ice in the Townships and possibly 2-5cm of snow in Quebec City.

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