Highpoint Weather
Published in

Highpoint Weather

Horseshoe Mountain (Thomas Horner)

Colorado Weather Forecast | Jan. 22–27, 2021

Active weather through mid next week, though impacts to the Front Range remain minimal.

Retrospective

Our storm for southwest Colorado on Monday and Tuesday panned out as expected, though parts of the Front Range and foothills saw an inch or two more than forecasted. Our ski resort forecast did okay, though we still had an issue with Taos.

A strong mountain wave set up yesterday over the Continental Divide in northern Colorado, which was responsible for some very gusty conditions in the foothills and even down to the plains at times. We posted about this on social media, but if you missed it, we took a cross-section of the forecasted atmospheric conditions to show where gusts were likely to be the highest.

(Annotations by Thomas Horner)

This ended up panning out quite well when looking at the actual gusts that were recorded:

via WeatherBell

Current Weather

(Laura Smith)

We saw beautiful standing lenticular formations and a broad wave cloud over Denver this morning. Lenticular and wave clouds occur as a result of mid and upper level winds interacting with and flowing over large topography, much like the Rocky Mountains.

via College of DuPage

GOES-East visible satellite shows the mountain wave over northeast Colorado. Standing lenticular formations are seen from above as clouds that remain stationary throughout the satellite loop. This persistent wave cloud prevented early daytime heating and kept temperatures over the I-25 corridor a few degrees cooler than yesterday.

(Annotations by Laura Smith)

A cross section along the 40th parallel reveals 20 knot ridgetop winds, 40 knot winds located 2000m (about one mile) above ridgetop, and an 80 knot upper level jet. These are excellent conditions for large standing mountain waves and lenticular formations.

via WPC

Weather stations this morning showed areas of light snow, fog, and haze in the mountains. We are still seeing a strong surface pressure gradient between the Continental Divide and the High Plains. With high pressure sitting over the mountains, and lower pressure developing in the southeastern region of the state, we can expect to see a lee cyclogenesis pattern emerging over the next 48 hours.

Lee cyclogenesis is a weather phenomenon that occurs when a dome of high pressure passes over a mountain range and vertically stretches as it descends into the lee of the range. This stretching creates a lee-side cyclone (area of low pressure at the surface). In our current case, low pressure in southeast Colorado will act on the cold air mass in Wyoming, pulling it south along the foothills. The leading edge of this air mass is where we find our cold front.

via SPC (Annotations by Laura Smith)

Light snow along ridge tops continued through today due to weak synoptic scale (large scale) lift from the right entrance region of the polar jet. Weather stations in the mountains indicate most of the snow showers have dissipated, but low level water vapor shows a few areas, such as Steamboat and Winter Park, continuing to see light snow through tonight. The northernmost mountain ranges, such as the Park Range (Steamboat), will continue to see flurries and light snow through the start of our storm on Friday night.

Forecast

via Pivotal Weather

This next storm is driven by a wave which will propagate south along the California coast through the start of the weekend. By Sunday, the upper level jet begins to lift out of the region while the trough simultaneously retrogrades (reverses direction and merges) with a second wave early on Tuesday.

via Pivotal Weather (Annotations by Laura Smith)

The first wave of this system will impact the state from Friday night into Sunday night, bringing snow to most mountain ranges. Unfortunately, Colorado will be under the left entrance region of the jet during this wave. Broad upper level subsidence could stifle snowfall totals expected from this storm and is responsible for a large amount of the uncertainty that still exists with the forecast — we’ll cover that in a bit.

via Pivotal Weather (Annotations by Laura Smith)

At 500mb, we find dynamic, mid level support from a perturbation over the Great Basin. Synoptic scale ascent is broadly located between the trough and ridge axes. The ridge axis over the Mississippi Valley region is annotated with a black zig-zag. Trough axes are annotated with black dashed lines. The region of interest, circled in blue, is located east of the perturbation axis. This could be responsible for persistent, if often weak, snowfall in the San Juans.

via Pivotal Weather

Westerly winds build pockets of moisture in mountain valleys and along west facing slopes by Saturday morning. While the available moisture is not necessarily impressive, it is sufficient for snow at altitudes above 5,000 feet.

via Pivotal Weather (Annotations by Laura Smith)

Denver International Airport (DEN) recorded a high today of 49°F, which was right in line with the forecast. The overnight temperature on the plains is expected to dip into the low 20s. Friday’s forecast looks similar, with partly cloudy skies and highs hovering around 50 and overnight lows in the mid 20s. By Saturday evening, lee cyclogenesis should begin to pull the cold air mass south across the High Plains.

via Pivotal Weather

Per the latest model runs, the urban corridor and High Plains may only get a few flurries with this frontal passage. Sunday’s highs should not surpass 40 on the plains. We might adjust this forecast as we get a little closer to the frontal passage (FROPA).

Upper level flow on Sunday looks a little more interesting as a possible jet max to to the south of Colorado sets up large-scale lift and southwesterly flow over the southern San Juans (Wolf Creek), providing another decent shot of snow during the day. Snow will shut off quickly by Sunday night as the trough tilts positively as it moves east. The central mountains will get a piece of this action, with the northern mountains and Front Range experiencing only residual effects.

via WeatherModels.com

The upside of this setup is quite good, (8–12 more inches of snow for Wolf Creek on Sunday), but it still has to fight against the aforementioned subsidence in the left entrance region of the jet to our east. The margins are pretty slim, and a small change in the location of the trough or in the perturbance in the flow could tip the balance and greatly reduce these totals.

The second wave from later on Monday and into Tuesday that should impact the San Juans again, but we wont be discussing it in any detail for now.

Overall, we are still seeing a strong signal for two very different solutions for Colorado, especially Wolf Creek, from now through Monday. The upside solution is that widespread, persistent moderate snowfall brings over two feet of snow to Wolf Creek and reasonable totals elsewhere. Over the past 12 hours, models have started leaning this direction.

The downside solution is significantly worse and still has quite a lot of support in the ensembles — subsidence greatly reduces snowfall rates and Wolf Creek only eeks out a foot of snow over four days, while the rest of Colorado gets even less. There are few solutions in between these two very different scenarios. A violin chart makes this more obvious:

Wolf Creek plume via University of Utah plume viewer

The arrows pointing at the top of the blue hourglass shapes show that there are a number of solutions with a more optimistic forecast. The arrows pointing at the bottom show a number of solutions with a pessimistic forecast. The hourglass is skinny in between these two areas, indicating that very few solutions fall in between.

You’ll notice that the medians fall towards the bottom of the ranges, and this is true with our website as well — the current Wolf Creek 50th percentile (median) forecast is for 7" of snow through Monday. The reason for this is that most members of the ensemble forecasts call for the drier solution. Meanwhile, 75th percentile is calling for 19" of snow — quite a bit different, and reflective of the optimistic solutions.

via HighpointWx.com

Luckily, most of the deterministic models, in addition to the high resolution models coming in today, are pointing towards the optimistic solution — which we currently think is the more likely than a bust. In conclusion: it seems likely that Wolf Creek will receive a couple feet of snow by Monday — but there is there is still a decent chance that snow totals overall could be a bit of a bust.

Let’s take a look at more optimistic expectations for the first wave. Most snow will fall early Saturday morning through Saturday evening.

via Weathernerds.org

Highest totals are found in the Park Range (thanks, in part, to snow falling fairly continuously from tomorrow morning up until the start of the wave), though totals drop off quite a bit towards the southern end of the range (Steamboat, Rabbit Ears Pass).

The westerly to southwesterly flow brings considerably more snow to the Elks (Aspen), Vail, and the San Juans than it does to Summit County, the Sangres, and parts of the Sawatch. Wolf Creek looks to have a bullseye of about a foot of snow by the time the heaviest snowfall wraps up on Saturday night, before reintensifying during the day on Sunday.

Our map of higher end totals looks pretty similar:

The lower end totals are pretty disappointing, however:

We went ahead and split our maps into two parts of this wave — the Friday night to Saturday phase, and the Sunday to Monday morning phase.

The maps for Sunday to Monday’s phase are similar in their large discrepancy:

Unfortunately, until this uncertainty is properly resolved, we will not be issuing tight forecast ranges for the resorts. We think it’s fair to communicate the level of uncertainty around this pattern, and while we think the upper end is more likely, it’s still a bit of a gamble if you’re driving six hours to ski Wolf Creek. Would we do it? Probably — but we would prepare ourselves for disappointment.

Later tomorrow we expect to tighten these ranges quite a bit, but for now, here they are.

Southern Colorado

Wolf Creek

  • Total: 8–24"
  • Friday → Saturday: 4–12"
  • Sunday → Monday: 4–12"

Silverton

  • Total: 10–25"
  • Friday → Saturday: 6–14"
  • Sunday → Monday: 4–11"

Purgatory

  • Total: 15–30"
  • Friday → Saturday: 8–15"
  • Sunday → Monday: 7–15"

Telluride

  • Total: 8–21"
  • Friday → Saturday: 5–11"
  • Sunday → Monday: 3–10"

Central Colorado

Aspen-Snowmass

  • Total: 4–10"
  • Friday → Saturday: 3–7"
  • Sunday → Monday: 1–3"

Buttermilk

  • Total: 2–7"
  • Friday → Saturday: 2–5"
  • Sunday → Monday: 0–2"

Aspen-Highlands

  • Total: 2–8"
  • Friday → Saturday: 2–5"
  • Sunday → Monday: 0–3"

Aspen Mountain

  • Total: 2–8"
  • Friday → Saturday: 2–5"
  • Sunday → Monday: 0–3"

Crested Butte

  • Total: 4–12"
  • Friday → Saturday: 3–7"
  • Sunday → Monday: 1–5"

Monarch

  • Total: 1–5"
  • Friday → Saturday: 1–3"
  • Sunday → Monday: 0–2"

Northern Colorado

Beaver Creek

  • Total: 2–7"
  • Friday → Saturday: 2–5"
  • Sunday → Monday: 0–2"

Vail

  • Total: 1–5"
  • Friday → Saturday: 1–4"
  • Sunday → Monday: 0–1"

Steamboat

  • Total: 4–13"
  • Friday → Saturday: 4–12"
  • Sunday → Monday: 0–1"

Copper Mountain

  • Total: 1–6"
  • Friday → Saturday: 1–4"
  • Sunday → Monday: 0–2"

Breckenridge

  • Total: 0–5"
  • Friday → Saturday: 0–3"
  • Sunday → Monday: 0–2"

Keystone

  • Total: 0–3"
  • Friday → Saturday: 0–2"
  • Sunday → Monday: 0–1"

A-Basin

  • Total: 0–4"
  • Friday → Saturday: 0–2"
  • Sunday → Monday: 0–2"

Loveland

  • Total: 0–4"
  • Friday → Saturday: 0–2"
  • Sunday → Monday: 0–2"

Winter Park

  • Total: 0–4"
  • Friday → Saturday: 0–2"
  • Sunday → Monday: 0–2"

Eldora

  • Total: 0–1"
  • Friday → Saturday: 0–1"
  • Sunday → Monday: 0–T"

Please check Friday evening for an update!

Forecast by
Thomas Horner
Laura Smith (@Hurricane_Laura)

@highpointwx
https://highpointwx.com

--

--

--

Weather forecasts and articles for the recreating in the Colorado high country — mountains, ski resorts, and crags.

Recommended from Medium

Why don’t we just replace all plastic with Vegware?

How can you make the world better when it’s easier to destroy than to create?

Memories & Happy New Year from MCWC — New Years tidings and remembering those we have lost

Managing Global Warming — Projects of the Future

There is Light because there is darkness — To care, or not to care

Wheat Traders Beware: Biden Warns Of Imminent Ukraine Invasion

SIDEHUSTLE UI/UX CAPSTONE PROJECT — GROUP 151

Get the Medium app

A button that says 'Download on the App Store', and if clicked it will lead you to the iOS App store
A button that says 'Get it on, Google Play', and if clicked it will lead you to the Google Play store
Highpoint Weather Forecasting Team

Highpoint Weather Forecasting Team

The Highpoint Weather forecasting team — weather nerds who like to play outside.

More from Medium

Day 362 — December 28th 2021

Adidas Future Talents — Here To Create (2018)

How the Pandemic Affected the Nerds

Improving Your Life With Optimism

Optimism and Go Be Great!