Tuesday, December 8, 2009

Blizzard Potential

The rumors are true: the first snowstorm of the winter season is going to be plowable, bordering on crippling south and east of the Twin Cities. The more I look at the maps the more I believe we may be very close to blizzard criteria, even here in the immediate Twin Cities. Here are a few storm "headlines":

* Get your errands done as soon as possible - conditions will gradually deteriorate as the day goes on with roads becoming increasingly icy and snow-covered.

* I expect about 1-2" by late afternoon, but the snow will pick up in intensity tonight. Right now it looks like we'll wake up to 5-6" of snow by Wednesday morning around the breakfast hour.

* Another 2-3" of snow is possible tomorrow as winds increase, causing considerable blowing and drifting of snow.

* I believe the worst driving conditions will come Wednesday morning/midday, with conditions only slowly improving (on freeways) late Wednesday and Wednesday night as winds start to ease up a bit. But getting to work/school Wednesday morning is going to be your worst vehicular nightmare. Leave early. Better yet: take the day off. Don't even chance it.

* Blizzard warnings are posted just south/east of the Twin Cities for Wednesday, but I'm concerned that the immediate metro may experience blizzard or near-blizzard conditions much of the day. A blizzard is defined as visibility under 1/4 mile in falling or blowing snow, wind speeds above 35 mph or so, capable of complete white-out conditions. That's what we're probably going to be faced with on Wednesday.

* Snow totals of 8-10" are now likely, with some 12"+ amounts south/east, from Lakeville to Hastings and Cottage Grove.

* Travel won't really begin to improve until Thursday. Unless it's an emergency, I would seriously consider delaying travel tomorrow. I have a hunch most schools (and many businesses) will be closed for the day.

* The snow will be followed by bitter cold, subzero lows likely Wednesday and Thursday night. getting stuck in a drift could be more than just an inconvenience - it could truly be life-threatening within 24-36 hours. Wind chills may dip into the -20 to -35 range by Wednesday night and Thursday morning.

Here is the latest GFS snowfall map, showing the projected path of heaviest snow. Even if the models are off by a factor of 2, we'll still pick up 5-6" of snow from this system, followed by bitterly cold, subzero air.

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