Thursday, October 14, 2010

Nor'Easter on the way

It is that time of year again when cyclonic storms, lows, depressions, Nor'Easters, Clippers, Colorado lows, whatever you want to call them, begin to develop some substance and pop to them. As the weather chills across the north the interaction between the tropics and the polar regions becomes more interesting and explosive. This will be evident in the next 24 hours as an upper level low spawns surface low pressure off the east coast near North Carolina. This low pressure will deepen rapidly and move towards Long Island, New York. The storm will then track across Maine and into Atlantic Canada. Typically these storms bring strong winds and heavy precipitation to our regions. This will be the case tonight as rain and wind will be on the increase from south to north. The heaviest rain in Quebec will fall along the US border where 40mm is possible (20-40mm for Montreal and the Seaway). Upwards of 50mm or more is expected in Vermont and New York. The wind will increase overnight out of the northeast from 30-50km/h then back to the north between 40-70km/h on Friday. As the wind comes out of the north, colder air will filter into the region changing the rain to wet snow across the highest elevations of the Townships, Green Mountains and Adirondacks by Saturday morning. A coating is quite possible in places. Temperatures even in the valley location will be chilly. Today we will reach 14C in Montreal but struggle to reach 8 or 9C Friday into Saturday. Skies will slowly clear on Sunday as the bulk of the storm moves east.

Eastern Ontario will remain on the western edge of the storm with gusty winds, periods of light rain and cold temperatures.

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