12:35 PM, Tuesday, January 3, 2017
The first round of snow in this cold spell was minor as expected (especially from the Denver-Boulder area southward), but the next snowy period beginning late Wednesday is likely to be more widespread and significant, with impacts on local travel Wednesday evening and Thursday.
The mountains and West Slope areas will continue a snowy week, with the main activity Wednesday and Thursday. Initially the heaviest snow will likely be north of I-70 on Wednesday, but spread throughout all mountain areas by Wednesday night. Snowy conditions may linger into Friday, especially to the south in the San Juans and Sangre de Cristo ranges. An additional 1-2 feet is likely in some areas creating avalanche hazards and winter driving conditions.
Front Range region
A lull in the snow (other than some flurries) is likely for the lower foothills and plains into Wednesday. But as the coldest part of the latest cold spell enters the region late Wednesday, a period of widespread snow (possibly a few heavy periods) is likely. The snow may hold off until after the Wednesday evening commute, but I think you should play it safe and plan on a snowy evening commute, especially north of Denver. Wednesday evening through Thursday morning will likely bring most of the snow, but light snow may linger into early Friday. Plan on wintry travel throughout the Front Range region on Thursday.
Temperatures will be at there coldest Wednesday night through Friday morning with nighttime lows -5 to +9 and Thursday daytime not getting out of the teens.
Most probable accumulations:
3-6″ high plains, DIA, Longmont, Greeley, Colorado Springs
5-10″ in and near foothills, Castle Rock, western suburbs of Denver, Broomfield, Boulder, Nederland, Cheyenne
localized reports over 10″ in lower foothills and Palmer Divide region
There is still some uncertainty about amounts (with small chances of lower or higher amounts). I would not be surprised to see the National Weather Service issue a winter storm warning for Wednesday evening in and along the foothills as new data become available later today. I’ll update tomorrow.
The next storm
We should enjoy a much milder weekend (especially Sunday). But a series of storms is hitting California with a particularly intense one beginning late in the weekend. Some of that moisture should make it to Colorado next week. Since the winds will be mainly westerly, it probably won’t produce much for the Front Range foothills and plains, but mountain areas may get another good round of snow.