First, the mundane part of the forecast.

Monday, Tuesday, Wednesday

From now through Wednesday afternoon, we'll see dry weather with some high clouds filtering the sunshine at times, and high temperatures will rise into the upper 20s to low 30s at most mountains. Morning lows will be variable, with upper-elevations staying warm (the 20s) while lower elevations see an inversion with temperatures in the single digits and teens (and even some readings below 0°F).

Stormy Period begins Wednesday Night

I love when my morning forecast routine becomes more difficult and time-consuming because that means multiple storms are coming.

Below is the European model's precipitation forecast for every six hours from December 23 to December 29. During almost every frame, precipitation (snow!) is forecast for our mountains. This is what I like to see and confirms what we had been thinking for a week or two, which is that the time around Christmas would get stormy.

Within this upcoming 6-day stormy period, there will be two or three more defined times with intense snow and potential powder.

Storm #1: Wednesday night – Friday

The first time with intense snow should begin around Wednesday night or Thursday morning and continue through Friday.

From a timing perspective, Thursday could be the storm day with some powder during the day, and Friday could be the deeper day since we will have had snow from Thursday, Thursday night, and more on Friday.

For snow amounts, this first system should favor areas farther to the south and west due to the wind direction. The wind direction will start from the southwest and transition to the west-southwest and eventually west.

Below, our multi-model snow forecast (in map view) does a good job forecasting the most snow at southern and western mountains with 12-24 inches for these spots. Other areas are in the 6-12 inch range, which feels correct to me because there will be enough storm energy to bring healthy snow totals even though these mountains will not be favored by the wind direction.

Below, NOAA's multi-model forecast for precipitation generally agrees with the OpenSnow forecast (above). Areas in orange are in the 1-2 inch range for precipitation, which should equate to 12-24 inches of snow (or more). Areas in blue are in the 0.5-1.0 inch range for precipitation, which should equate to 6-12 inches of snow.

I have high confidence for deep snow totals (12-24" or more) at Wolf Creek, Silverton, and the West Elk Mountain west of Aspen and Crested Butte.

I have moderate confidence for pretty deep snow totals (8-16") around Telluride and Purgatory (the wind direction isn't perfect for these spots, but they should still do well), Crested Butte (which gets the most snow from a west-southwest wind, so the longer this wind direction stays around, the deeper the snow), Aspen, and maybe Steamboat (which does well with a west wind).

Other areas should still do pretty well with 6-12 inches, but totals should be lower than the mountains I mentioned above. At these mountains with 6-12 inches, snow totals Thursday and Friday might not be super impressive, but if new terrain opens, the fun factor could be pretty high.

View: Colorado 10-Day Forecasts

To recap Storm #1, expect snow from Wednesday night through Friday with some powder on Thursday and deeper powder on Friday.

Following Storm #1 from Thursday into Friday, there will be one or two more times with intense snow.

Storm #2: Saturday – Sunday (maybe)

Two models show this period of intense snow (European and American GFS models) and two models do not show this period of intense snow (Canadian and German models). When the European and American GFS models agree, especially 5-6 days into the future, that adds some weight to their forecast in my mind, so I am closely watching the weekend (Christmas Day and the next day) to see if we could get more intense snow, or if snow will be in the air but maybe with lower accumulations.

Storm #3: Monday – Tuesday

All four major models that I talked about above show generally the same thing for early next week, which is that the last push of stronger stormy energy (vorticity maximum) will move through the Rockies and Colorado with another period of intense snow. Right now, it looks like Monday, December 27 could be a stormy day with snow waning on Tuesday, December 28. We'll work on the details of Storm #3 as it moves closer in time.

Longer Range

A region of stormy weather and cold air will stay over the Rockies during the end of December 2021 and into early January 2022. This is good news because it means that chances for snow will continue. But it's too far into the future to know if this pattern over the Rockies will bring a lot of snow or a little bit of snow here in Colorado.

Forecast Note for Tuesday

My forecast for tomorrow, Tuesday morning, December 21, might be delayed. I am taking advantage of the calm weather (warm, not snowing) to spend the night with friends and family (including young kiddos!) at a hut on Vail Pass. I *think* cell coverage there is adequate for me to get data and write a new forecast, so things should be normal on Tuesday morning. But if cellular data is very slow, I might not be able to update the forecast until Tuesday late morning. Usually, I do not go on hut trips during the core of the season because I can't get data to write a forecast, but I think that this should work out ok.

Join me on YouTube Live on Wednesday, December 22 @ 700pm

I'll answer your questions (last time there were 40+ questions) and talk in detail about the upcoming storms. I share my screen during the entire live discussion and use graphics to visually explain the forecast. The last session was super fun and I hope that you can join this one. The screen is just me presenting, so there's no need to show your potentially unkept-mid-winter-disheveled face – just pop by to listen and watch:-)

Link: YouTube Live

Submit Questions: Click HERE

Thanks for reading!

JOEL GRATZ

By the way…

The significant changes to OpenSnow that I've talked about for the last week are now live. If you're an All-Access subscriber (thank you!), you'll see no changes. If you are not an All-Access subscriber, here is an FAQ with more details about the upcoming changes, and we hope that eventually, we'll earn your support. Also, you can watch 2-3 minute videos about these changes made by myself, our Tahoe forecaster BA, and our Utah forecaster Evan. And finally, check out our Utah forecaster Evan's Twitter thread showing exactly how he uses OpenSnow's All-Access features to track powder.

Geography Key

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

Along the Divide
Loveland, Arapahoe Basin, 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