Sunday, December 05, 2010

Cold and snowy

We have a difficult weather scenario setting up early on this Sunday morning. Lets start with yesterday, it was a chilly, breezy and in some locations in southern Quebec, snowy Saturday. We have a blocking area of high pressure located over the far north Atlantic. This is steering weather back west into eastern Canada, and blocking any southern or western systems from moving east. We call this retrograding when low pressure acts against natures "rules" and moves the wrong way. Low pressure one was fairly week and produced that light snow yesterday. This morning we have a brisk northwest flow of cold air pouring into the region. I had -7C this morning with a gusty wind. It will remain cold today struggling to reach -4C with an increasing wind to 40km/h. These winds will turn on the snow machine around the Great Lakes with heavy snow forecast southeast of Lake Huron all the way down to the shores of Lake Erie and Ontario including portions of the GTA and Highways 400 and 401.

The cold air will only deepen on Monday as another stronger storm approaches form the Atlantic and is drawn into Quebec. This storm will produce snow and blowing snow with winds increasing to 60km/h over southern Quebec including Montreal. Quantities of snow are difficult at this time to predict. Winter Storm Watches are in effect for portions of the St. Lawrence Valley north and east of Montreal where 15cm or more is expected. So far Montreal is forecasting 5cm as we will be on the western edge of the precipitation. It will be windy and chilly right into Tuesday. Any snow that does fall will be blown around. Travel could become a challenge for Monday and Tuesday. Eastern Ontario including Ottawa and Kemptville will be windy and cold with flurries, sandwiched between the system snow in Quebec and lake effect in Ontario.

I will update this potential storm as the day progresses.

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