Tuesday, November 23, 2010

Anatomy of a warm front

The low clouds, drizzle and fog finally lifted this afternoon, pushed off to the southeast by an advancing cold front. The temperature was held down on the island of Montreal until late in the day today when it shot up to 13C. It only lasted a an hour or two until the cold air behind the front began to settle into the valley. We are heading below freezing tonight with a chance of flurries and quite breezy. I am posting the observations from Environment Canada's Montreal office below. You can see the bizarre temperature swings. Pay close attention to the wind direction. Note as well that while we were struggling to reach our high temperature today, just along the south shore they were 10C as early as 9am this morning. This is typical in Montreal in these situations where the cold dense air does not move off the valley floor. Freezing rain often last hours longer here than regions just to our north and south. We may see the same scenario play out Friday.

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