Monday, December 26, 2011

First storm Tuesday?

Sanding the icy roads on Ile Perrot on Christmas Eve. (ValleyWX)

Time for Boxing Day shopping and the weather is perfect, a vast improvement in road conditions over yesterday. Low pressure skirted along the international border on Christmas Day giving a decent snowfall and white Christmas to the St. Lawrence Valley with cool temperatures. Montreal managed about 4 to 7cm of snow, perfect for a Christmas card, not so good on the roads. Numerous cars hit the ditch along the Trans Canada Highway (40/417) to Ottawa and also north into the Laurentians along Highway 15. The roads are in good shape today and should remain that way into Tuesday. Temperatures yesterday ranged from above freezing in the Richelieu and Champlain Valleys due to a south wind to a very cold -7C here on Ile Perrot with a cold and damp northeast wind.

That is the good news, now the bad, the weather will turn nasty again late Tuesday and into Wednesday morning when travel could become quite dangerous. Low pressure will develop in the southern US and move across southeast New York state and into New England. It has been a difficult track with plenty of warm air pushing north again, therefor computer forecast models have been flip flopping between snow and rain for the last several days. It appears mixed precipitation will spread across the region late on Tuesday and change to all snow overnight into Wednesday from northwest to southeast. At this time at least 5cm of snow is expected for Montreal and Ottawa along with some rain and freezing rain. The potential exists for more, and warnings may be needed for a portion of our forecast region. The big threat with this storm will be the rapid drop in temperatures on Tuesday night across southern Ontario and Quebec, along with a flash freeze. The rapidly dropping temperatures, gusty winds and precipitation will make for very icy roads for late Tuesday in Ontario and Wednesday morning in Quebec.

I will update the information on this potential storm later today via the blog and twitter. Happy Holidays, be safe.

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