The weather on Sunday should be dry for most of the state. The storm that split around Colorado on Saturday afternoon is still close enough to affect our weather, and low clouds have formed in the northwest corner and also east of the mountains.

On Monday, Tuesday, and Wednesday, expect dry weather to continue with at least partly sunny skies and reasonable temperatures. Overnight low temperatures will be in the teens and 20s, which is cold enough for snowmaking, and daytime highs will be in the 30s.

Our next chance for snow will arrive on Thursday as a reasonably strong storm moves into Colorado from the northwest. A part of this storm will likely slow down and drop south of Colorado, and because of this complexity, I do not have high confidence in snow amounts.

The University of Utah ensemble, which shows a range of forecasts from the American GFS and Canadian models, highlights about 3-6 inches for most mountains in Colorado on Thursday, December 21st. This range feels about right as a first-guess forecast with the storm still four days away. The graphic below is for McClure Pass, just west of Aspen in the central mountains.

If you want to ski fresh snow, plan on skiing Thursday.

Following the snowfall on Thursday, Friday will likely be dry and chilly.

Then, on Saturday, December 23rd or on Saturday night, an Arctic cold front should move into Colorado, and the frigid air should last through about Tuesday, December 26th or Wednesday, December 27th.

Temperatures will likely be 10-25 degrees below normal (see map above), and the coldest air will likely stay over the northern mountains and near and east of the divide with temperatures possibly staying below 0F all day and night.

Weak-to-moderate strength storms may ride along the edge of this Arctic air, so there is a possibility for light snow accumulations at some point during the cold snap, though snowfall rates would likely be on the lower side due to the lack of moisture in the cold air mass. If the coldest air stays a bit further east (very possible), then perhaps these storms riding along the edge of the cold air could bring a bit more snow.

Beyond about December 27th, I have zero clue about any details of the forecast through New Years and beyond. When there is consistency in the 10+ day forecast, I'll let you know.

Thanks for reading!

JOEL GRATZ

10-Year Anniversary Party!
Monday, December 18th at West Flanders in Boulder, CO at 700pm
* I wrote my first snow forecast email titled "Colorado Powder Forecast" on December 18, 2007.
* Ten years (and lots of powder days) later, let's party.
* I will give a short talk to start the night off.
* Wear your Colorado Powder Forecast t-shirt and I'll buy your drinks:-)
* Happy hour prices all night
* Details and RSVP: https://www.facebook.com/events/836050909911243/

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Geography Key

Northern Mountains
Steamboat, Granby, Beaver Creek, Vail, Ski Cooper, Copper, Breckenridge, Keystone, Loveland, Abasin, Winter Park, Berthoud Pass, Eldora, Rocky Mountain National Park, Cameron Pass

Along the Divide
Loveland, Abasin, Winter Park, Berthoud Pass

East of the Divide
Eldora, Echo, Rocky Mountain National Park, Cameron Pass

Central Mountains
Aspen, Sunlight, Monarch, Crested Butte, Irwin, Powderhorn

Southern Mountains
Telluride, Silverton – north side of the southern mountains | Purgatory, Wolf Creek – south side of the southern mountains