Monday, January 28, 2013

Active weather week - temperature roller coaster

More snow and ice are forecast for a portion of this week. Roads are expected to be slippery so slow down. Let's avoid scenes like the accident above that involved 85 vehicles on the 401 near Oshawa on Friday. (Toronto Star)
We have been in the deep freeze for a week now but a rapid end to it is in sight. The temperature this morning is at -12C here on L'Ile Perrot which is as warm as it has been since last Sunday. We will see clouds thicken followed by some steady snow by the lunch hour. The snow has been coming down hard in some places across southern Ontario and upstate New York, so I see no reason not to expect the same here in the St. Lawrence Valley. I expect a good 5 to as much as 10cm of snow will fall by midnight. The culprit is a long warm front way out ahead of low pressure developing over Colorado. This system will bring very warm air into out area with highs today in the -7C range, up to 0C by Tuesday and soaring to near record values of over 10C (50F) by Wednesday.

Along with the warm air will come a surge of moisture, so after the snow today look for a period of freezing rain by Tuesday afternoon from Kingston to Ottawa and east to Montreal. I imagine warnings for icy precipitation will be widespread, but at this time they have been posted only for southern Quebec. It is a little early for the event as we have the snow first but other regions around should be posting warnings as well by later today. By Wednesday it will be all warm air with rain, at time heavy and even the risk for a rumble of thunder. Record highs of plus 9 to as high as 14C (48-58F) are possible in southern Ontario and Quebec as well as New York and Vermont. The bizarre January weather will continue on Thursday as a cold front brings us back to reality with windy conditions, some snow and temperatures falling to -6C. It will be a challenging week for driving so take it slow out there and show some courtesy. Last week we saw a rash of accidents across the region including one involving 85 vehicles that closed the 401 in both directions near Oshawa for several hours late Friday.

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