Colorado Weather Forecast #147: Nov. 25 - Dec. 3, 2021

Updated Sat Nov 27, 2021 12:00pm MST | Published Thu Nov 25, 2021

By Thomas Horner

7-Day Snow Planner

Summary

• Overproductive storm yesterday.
• Denver technically continues its snowless streak, though many parts of the metro area got accumulations.
• Generally warm and dry for the next seven days.

Retrospective

Hello again everyone, and apologies about the absence. Yesterday was a sneaky powder day across central Colorado as instability helped fuel some stronger cells of snow (with fluffy 20:1+ SLRs).

This system was not expected to produce more than a few inches of snow, and meteorologists and weather models were caught off guard by some of the impressive snow reports. Many totals exceeded the 90th percentile of the Blend’s forecast, which means almost every single weather model underforecasted this significantly.

Ski Area Totals

Here are some observations for ski areas:

• Aspen Snowmass: 10” (Official)
• Aspen Highlands: 10” (Official)
• Buffalo Pass: 6-9” (SNOTEL)
• Copper: 7” (Official)
• Breck S.A.: 7” (Official)
• Beaver Creek: 7” (Official)
• Aspen Mtn: 7” (Official)
• South Colony Lakes: ~6-7” (SNOTEL)
• Vail S.A.: 6” (Official)
• Winter Park: 5” (Official)
• Buttermilk: 5” (Official)
• Wolf Creek: 5” (Official)
• Red Mountain Pass: ~5” (SNOTEL)
• Cameron Pass: ~5” (SNOTEL)
• Telluride S.A.: 4-5” (Webcam)
• Berthoud Pass: ~4” (SNOTEL)
• Purgatory: 4” (Official)
• Keystone: 3” (Official)
• Monarch: 3” (Official)
• Steamboat: 2-3” (Webcam)
• Taos S.A.: 2” (Official)
• A-Basin: 2” (Official)
• RMNP: 1-2” (SNOTEL)
• Loveland S.A.: 1.5” (Official)

The fluffy snow-liquid ratios were nice for the sneaky powder day, but it also means that not a lot of water fell. We’re still struggling with the start of our winter season.

On the Front Range, a cold front in the evening helped set up a slight easterly wind component for a few hours, which tapped into some low-level moisture and produced snow across the western and southern metro area thanks to the shallow upslope.

A few areas in the foothills and western suburbs managed to pick up more than a couple inches of snow. Even areas near downtown Denver recorded measurable snow.

Denver International Airport observed snowfall last night and this morning, but it didn’t accumulate. Thus, officially, Denver’s snowless streak continues and every day the city goes without snow is a new record the latest first date of measurable snow (since records began in the 1800s). This also marks 218 days since the last measurable snow event which was on April 21.

Denver: Longest Consecutive Days Without Measurable Snow

1. 235 days (1887)
2. 227 days (1888)
3. 224 days (1889)
4. 220 days (2021)
5. 219 days (1886)

Looking at the weather forecast, it seems fairly likely that Denver will take the #3 spot on this list. This streak also coincides with a very dry summer, and Denver will set a record for the driest June - November on record.

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)

Cue the debate about the official record, since parts of central Denver technically picked up measurable snow with some observations of 0.1”! Would the first snowfall have come if the official weather station was still at the old airport, or downtown?

Front Range Totals

Anyways, here are some observations from the Front Range with the past storm:

• Arvada: 0.5-2” (CoCoRaHS)
• Aurora: 0-0.1” (CoCoRaHS)
• Boulder: 0.1-0.5” (CoCoRaHS)
• Broomfield: T-0.4” (CoCoRaHS)
• Central Denver: T-0.1” (CoCoRaHS)
• Coal Creek: 2-3.5” (CoCoRaHS)
• Conifer: 1.5” (CoCoRaHS)
• Colorado Springs: T-0.2” (CoCoRaHS)
• Denver NW: 0.1-0.5” (CoCoRaHS)
• Denver SW: 0.1” (CoCoRaHS)
• Denver NE: 0-T (CoCoRaHS)
• Evergreen: 1-2” (CoCoRaHS)
• Fort Collins: 0” (CoCoRaHS)
• Golden: 1-3” (CoCoRaHS)
• Greeley: 0-T (CoCoRaHS)
• Highlands Ranch: 0.2” (CoCoRaHS)
• Ken Caryl: 1” (CoCoRaHS)
• Longmont: 0” (CoCoRaHS)
• Lookout Mountain: 2.8” (CoCoRaHS)
• Loveland: 0” (CoCoRaHS)
• Nederland: 0.5” (CoCoRaHS)
• Pueblo: T-0.2” (CoCoRaHS)

The Next Seven Days

Ridging dominates the western United States over the next week, with very little snow forecasted for any of the mountainous states. Here’s the average geopotential height over the next seven days, which shows a strong ridging signal and dreaded dipole pattern (strong troughing in the east):

Denver: Temperatures At-A-Glance

Forecast Discussion

Let’s start with a baseline of high temperatures in the 60s in Denver and most of the high plains, 50s in the foothills and lower valleys, and 30s-40s in the mountains. Let’s also consider that winds will be gusty along and east of the Divide in northern Colorado, and skies will be mostly sunny. Here’s where see some exceptions to the forecast:

Saturday Shortwave

A weak shortwave barely brushes Colorado. The only real impact is knocking temperatures back down by about 10 degrees and bringing some cloud cover. No accumulating snow is expected in the state.

Tuesday Shortwave

An even weaker shortwave could brush Colorado which would knock temperatures back by maybe 5 degrees on the Front Range, with no impacts elsewhere in Colorado. This would bring some short-lived cloud cover too.

Wednesday and Thursday Warmth

Denver will approach near-record high temperatures as most of the state sees highs 15-30 degrees above average. The metro area could hit the low 70s due to strong warm air advection behind Tuesday’s wave.

Friday: Stronger Shortwave

Models are showing a more productive shortwave from Friday to Saturday. This would kick a cold front down the Front Range by Friday afternoon. Lift and moisture are very limited, so snow totals from Friday to Saturday would likely be minimal.

90th percentile (very optimistic) snow accumulations by Saturday morning are 1-4” across most of the Colorado high country. We could remain unsettled through the weekend with another couple inches of snow coming by Sunday morning, but there is very little certainty about impacts.

Winds would be quite strong on Friday and Saturday as the associated jet encroaches on Colorado.

Long Term

The Climate Prediction Center keeps Colorado fairly neutral in terms of precipitation anomalies in their 2-3 week and monthly outlook.

Though the immediate two week forecast is not favorable.

Analogs have ridging over the west at least starting to break down, which is better than a pronounced blocking pattern.

The latest Euro weekly has an above-average December, after a slow start the first week.

This is also corroborated, to a lesser extent, on the extended GFS.

So there’s some hope that we can get into a more favorable pattern. Things can change quickly! The snow seasons of 2007-2008 (strong La Niña), 2008-2009 (weak La Niña), and 2016-2017 all started off worse than this but ended up well above average by January. Keep doing your snow dance.