11:45 AM, Wednesday, January 4, 2017
The winter storm is upon us. Steady accumulating snow has been falling this morning in northern Larimer County and southeastern Wyoming and that area should spread south this afternoon and replace the intermittent light snow currently in the Denver-Boulder area. A large area of light snow tonight and Thursday will likely be punctuated with periods of heavier snow this evening into early Thursday. Expect a snowy commute this evening (mainly from Denver northward) and Thursday morning will likely bring very cold temperatures, snow-packed roads, and airport delays. Snow should taper off from north to south Thursday morning and early afternoon.
Temperatures along the Front Range today and Thursday will struggle to make it to the teens, and nighttime lows should be -5 to +5.
Lots of snow with 1-2 feet through Thursday (lingering into Friday in southern Colorado).
Front Range Snow
The heaviest periods of snow will likely organize in west-to-east bands this evening into early Thursday morning, and mainly form Denver northward.
1-4″ Colorado Springs
3-6″ south Denver suburbs, Castle Rock, Aurora, DIA, Longmont, Greeley
5-10″ north Denver suburbs, Golden, Broomfield, Boulder, Fort Collins, Cheyenne
8-12″ Idaho Springs, Nederland, Estes Park
Why so much snow when it’s so cold and dry?
It’s true that the temperatures and dewpoints are quite low along the Front Range. But unusually moist and less cold Pacific air is in western Colorado and is riding over the top of our very cold low-level air along the Front Range. So weak upslope flow (easterly) combined with copious Pacific moisture from the west is helping to make it snow east of the continental divide.
Next week’s big storm
A very wet Pacific storm and accompanying atmospheric river (long fetch of unusually moist air from the ocean) will likely make headlines this weekend due to extreme rain and snow in California. Some of that moisture should make it to Colorado late Sunday and Monday and may result in more heavy mountain snows (and maybe valley rain) in western Colorado. It does not appear the Front Range will get much precipitation from that, but temperatures are likely to be quite balmy Sunday and Monday.