Tuesday, December 08, 2009

Snowfall Warning

Light snow along the Kemptville Creek in North Grenville yesterday. Just a "warm up" for the main event tomorrow. Photo by J. Kinnear

Environment Canada has posted a snowfall warning for southern and central Quebec for Wednesday. In Ontario for some reason no warnings have been issued yet despite a similar forecast for the St. Lawrence Seaway and Ottawa. I guess with the precipitation primarily falling as rain in the GTA, there appears to be no rush to advise the public of this dangerous winter storm. As the first storm of the year, it will be impressive tracking from Colorado towards Chicago and then north of Montreal. A heavy burst of snow will develop Wednesday morning in southwest Quebec and spread north and east. The snow will mix with sleet and rain in the afternoon in Montreal. Accumulations in our region will be in the order of 15-30cm with 15 at the US border and 30cm in the mountains of New England and north of Montreal. In addition to the snow gusty east winds will approach 60km/h before backing to the northwest Thursday and reach speeds up to 90km/h. The winds will blow around whatever falls.

We are not alone with this storm. Strong winds and heavy snow are falling from Arizona to Illinois with blizzard warnings in effect on the backside of the storm. In the warm sector severe thunderstorms are expected from Texas to Georgia.

Closer to home a Winter Storm warning is in effect for the Adirondacks and Green Mountains, with a Winter Weather Advisory in the Champlain and St. Lawrence Valley. A High Wind Watch has also been issued for New York and Vermont.
This is a difficult storm to forecast with bitter arctic air to the north and very warm air streaming in aloft. The forecast is very changeable so watch for updates today and prepare for nasty weather.

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