Colorado Weather Forecast #147: Dec. 1 - Dec. 8, 2021

November in review, and our forecast: warm and dry, though cooler this weekend. Next storm around December 7th.

This forecast is no longer valid. Please return to our list of forecast articles to find more recent posts.

Updated Tue Nov 30, 2021 12:00pm MST | Published Tue Nov 30, 2021

By Thomas Horner

7-Day Snow Planner

223

Days since the last measurable snowfall in Denver (At the official weather station / 4th longest streak since record keeping began)

14%

Chance of accumulating snow in Denver by Dec. 8th (At the official weather station)

Northern Mountains

Park Range and N Front Range: Steamboat, Buffalo Pass, Rabbit Ears Pass, Bluebird, RMNP, IPW, Cameron Pass

6am New Snow

0"

Thu

0"

Fri

0"

Sat

0-T

Sun

0"

Mon

0-3"

Tue

1-7"

Wed

6am Powder Potential

0%

Thu

0%

Fri

0%

Sat

0%

Sun

0%

Mon

0%

Tue

15%

Wed

I-70 Corridor

Front Range, Gore Range, etc.: Winter Park, Berthoud Pass, Jones Pass, Loveland, A-Basin, Keystone, Breck, Copper, Vail Pass, Vail, Beaver Creek

6am New Snow

0"

Thu

0"

Fri

0"

Sat

0-T

Sun

0"

Mon

0-2"

Tue

T-5"

Wed

6am Powder Potential

0%

Thu

0%

Fri

0%

Sat

0%

Sun

0%

Mon

0%

Tue

15%

Wed

Central Mountains

Elk Mountains, Sawatch Range, Grand Mesa, West Elks: Aspen Resorts, Crested Butte, Powderhorn, Sunlight, Kebler Pass, Independence Pass, Cottonwood Pass, Monarch

6am New Snow

0"

Thu

0"

Fri

0"

Sat

0"

Sun

0"

Mon

0-2"

Tue

T-5"

Wed

6am Powder Potential

0%

Thu

0%

Fri

0%

Sat

0%

Sun

0%

Mon

0%

Tue

15%

Wed

Southern Mountains

San Juans: Telluride, Red Mountain Pass, Silverton, Coal Bank Pass, Purgatory, Wolf Creek

6am New Snow

0"

Thu

0"

Fri

0"

Sat

0"

Sun

0"

Mon

0-1"

Tue

0-7"

Wed

6am Powder Potential

0%

Thu

0%

Fri

0%

Sat

0%

Sun

0%

Mon

0%

Tue

20%

Wed

Summary

  • Warm and dry!
  • Low chance of light snow for northern Colorado on Sunday, but otherwise, just a slight cooldown from Friday to Sunday.
  • Storm December 7th-ish. Not enough certainty to forecast any specifics.

November In Review

It’s been an unusually dry and warm month across much of the western United States. The temperature average for this November has been 3-6 degrees Fahrenheit above the usual.

(via WeatherBell)
(via WeatherBell)

Precipitation has been below average across the board, except perhaps a few spots.

(via WeatherBell)
(via WeatherBell)

This is reflected in the snowpack observations from automated SNOTEL sites across the Colorado high country.

(via NRCS)
(via NRCS)
(via NRCS)
(via NRCS)

Most storms this month featured northwest flow, and thus the dry signal is even more pronounced in southern Colorado. Mountain ranges like the San Juans have seen very little new snow over the course of the entire month.

(via NRCS)
(via NRCS)

That’s not too out of the ordinary for the region though. You can see from the above graph that the winter can start out pretty dry, then there is a pronounced uptick in spring, when Colorado is more frequently impacted by cutoff lows that track over the desert southwest and bring southwesterly flow.

This is certainly a disheartening start to winter, but as we mentioned in our previous forecast, we’ve seen seasons start this poorly and end up well above average by January. The clock is ticking – will we get into a more consistent, productive pattern?

Denver

Denver’s weather for November, like much of the rest of the state, has been far from seasonal. Only trace amounts of precipitation were recorded (on two separate days), and temperatures have almost never dipped below normal.

(via NWS)
(via NWS)
(via NWS)
(via NWS)
(via NWS)
(via NWS)

Denver: Longest Consecutive Days Without Measurable Snow

  1. 235 days (1887)
  2. 227 days (1888)
  3. 224 days (1889)
  4. 223 days (2021)
  5. 219 days (1886)

Denver: Least Amount of Precipitation From June to November

  1. 1.88” (2021)
  2. 2.46” (1939)
  3. 2.56” (1934)
  4. 2.76” (1879)
  5. 2.81” (1917)

Current Conditions

Satellite imagery shows a weak cold front moving through this morning.

(via NOAA)
(via NOAA)

This is associated with a weak shortwave passing over the region today.

(via WeatherBell)
(via WeatherBell)

Today will be the coolest day this week (unless Friday ends up a bit cooler than forecasted), but temperatures are still well above average for the last day of November.

(via WeatherBell)
(via WeatherBell)

Forecast Discussion: Rest of the Week

Ridging continues to build over the western United States. Warm air advection behind today’s shortwave brings some very unseasonable temperatures on Wednesday and Thursday.

(via WeatherBell)
(via WeatherBell)

Temperatures will likely get well into the 70s on the plains and the 50s in the lower elevations of the high country (Vail, Aspen, Telluride, Steamboat).

Ridging doesn’t look to meaningfully break down until next week.

(via WeatherBell)
(via WeatherBell)

A lone exception is the latest run of the operational GFS model, which does have a weak shortwave bringing light snow to northern Colorado on Sunday morning. However, this model is in disagreement with its own ensemble in addition to every other weather model out there.

Regardless, there’s enough of a ripple in flow aloft to kick a surface front into Colorado on Sunday which would at least briefly cool us down. There’s an even weaker front on Friday as well.

(via WeatherBell)
(via WeatherBell)

Overall, we’re looking at cooler temperatures from Friday to Sunday, though it’s still likely they’ll be above average for the start of December – highs in the high 50s to mid 60s for the plains / urban corridor, and highs still near or above freezing below treeline in the mountains.

Let’s check again in a couple days to see if this forecast trends even warmer, or if the GFS is on to something and we see a few inches of snow in the forecast for northern Colorado.

Forecast Discussion: Storm Next Week

We finally, FINALLY see a decently strong storm signal in the ensembles for next week, around December 7th.

(via WeatherBell)
(via WeatherBell)

However, it’s not a sure bet this will actually deliver a wallop of snow or cold temperatures to Colorado. For instance, the latest run of the operational Euro model has the energy splitting around Colorado.

(via WeatherBell)
(via WeatherBell)

Even in this particular scenario, most of Colorado’s high country could get over a foot of snow – however, if we trend towards an even more progressive and/or split pattern, we’ll start to see snow potential dwindling.

(via WeatherBell)
(via WeatherBell)

The GFS has a much less progressive solution and a much deeper trough that eventually evolves into a closed low.

(via WeatherBell)
(via WeatherBell)

This would bring a strong dose of moist southwest flow to Colorado, with 1-2 feet of snow in the San Juans (and much less snow for northern Colorado).

(via WeatherBell)
(via WeatherBell)

Snow is also more likely in Denver with this pattern thanks to lee cyclogenesis setting up a strong center of low pressure over southeast Colorado.

Right now we lean towards the Euro’s solution as it handles this sort of setup better at long range.

Clearly, models lack any real agreement on December 7th’s snow potential beyond the fact that it definitely exists. While it would be really nice to buy into the operational solutions (where some mountain ranges in Colorado are getting double digits of snow), the ensembles don’t really support a particularly snowy solution just yet.

The Euro’s ensemble only has a 10-20% chance of more than 6” of snow across Colorado, with the GFS ensemble looking much more optimistic (40-60%) and the Canadian extremely pessimistic (<10%).

Even then, a blend of all solutions doesn’t look too terrible, with decent snow for western Colorado, though Denver still avoids picking up measurable snowfall.

Overall this in line with analogs which suggest that historically, these sorts of conditions have led to snowfall in western Colorado.

(via CPC)
(via CPC)

Still, long term forecasts don’t look much more than “La Niña-y…” and despite next week’s system, we’re not seeing a significant, prolonged pattern change.

(via CPC)
(via CPC)

Teleconnections do suggest a more potent and consistent pattern around the end of the third week of December.

Anyways, we’ll keep you updated on next week’s storm potential. For now, enjoy the sun…

--

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