Colorado Weather Forecast #177: Mar. 15, 2022 - Mar. 20, 2022

Updated Mon Mar 14, 2022 10:00pm MST | Published Mon Mar 14, 2022

By Thomas Horner

7-Day Snow Planner

Summary

• Warm, wet storm from Wednesday afternoon to Thursday for the Front Range.
• Mountain snow totals may be disappointing – right now, we’re thinking 3-8” along/east of the Divide and Trace to 5” elsewhere.
• Models still can’t decide on some of the smaller-scale dynamics, and thus whether the Denver area (particularly the foothills to the west and south) or the Colorado Springs area (particularly the foothills to the west and north) get better snow.
• Disagreement on temperatures and precipitation totals. In general, warm temperatures along the urban corridor will result in a large proportion of the precipitation falling as rain. Snow that does fall will be dense and a lot of it may melt upon hitting the surface. Thursday morning may be tough travel conditions across the Front Range due to freezing temperatures and wet surfaces.
• A lot of moisture, the potential is still there for a double digit snow totals in the Front Range, though this is likely relegated to the foothills.
• In general, ensembles have been trending downwards for this event.
• More snow on the way: early next week looks to have some very decent snow totals!

Forecast Discussion

Hello everyone. Thought we’d jump into the fray here and talk about a system that will impact Colorado from Wednesday to Thursday.

The setup is not terribly exciting – we have a broad, shallow upper level trough tracking over the western United States, with a deepening mid level shortwave dropping into New Mexico on Wednesday/Thursday.

This wave wont drag down particularly cold air, but it will be advecting in some pretty deep moisture into Colorado and getting an upslope going along the Front Range.

If this system was further north, we’d potentially be looking at another very potent storm like the March 13th bomb cyclone from a couple years ago or the Pi Day storm from last year, but alas. The surface low looks to develop way down in New Mexico and track across Texas.

Still, models have putting down some very nice precipitation totals across the Front Range, even if a good chunk of that is rain or wet, slushly snow. East of the Divide, the water column looks saturated from the surface up to the mid atmosphere, so any sort forcing will result in widespread precipitation.

West of the Divide, dynamics are not as great nor is the moisture as deep, so only a few inches of snow are expected for many mountain ranges, though there’s enough ingredients at play for some powder potential in a few areas.

With the southerly track of the system, we’re looking at south of the Palmer Divide as the potential bullseye for snow (Colorado Springs – or rather, the higher terrain to the north and west of the city), but models still haven’t converged on this solution, and there’s still a decent chance that Denver and particularly the southwestern foothills and ‘burbs win out. It’s unlikely that areas north of Longmont will see much precipitation.

For the urban corridor, the biggest question is temperatures – a lot of this precipitation could fall as rain.

Timings

Generally, precipitation will occur from Wednesday morning (generally light and spotty), intensifying on Wednesday afternoon (some banding), and becoming widespread and consistent on the Front Range through Thursday morning.

Mountain Snow

This is a tough one and looks to be a bit overforecasted. Banded snowfall on Wednesday evening may make the biggest impacts overall and it’s hard to forecast right now which areas may win out.

With a fairly dry northerly upslope for much of the mountain ranges, not expecting much snow outside of the banded snow event. Areas along the Divide and east (Loveland S.A., Winter Park, A-Basin, Eldora) may get a piece of the action but possibly just a few more inches than other areas. Potentially 3-8” by mid-day Thursday, with Trace to 5” for other areas.

Precipitation Totals: A Look at the Models

Let’s take a look at precipitation totals. We’ll show you how a variety of weather models are looking tonight.

The GFS

The GFS has been holding fairly steady in calling for a decent snow event for Denver, Boulder, and the nearby foothills, with decent impacts down to Pueblo. Most of this precipitation comes as snow. You can multiply the values show in this image by 10 for snow totals (so about 6” for Denver, for instance):

The ECMWF (Euro)

The more dependable Euro model has had a less exciting solution for the past couple days (barring the 06Z run this morning which had more than a foot of snow for Denver…we’ll ignore that).

The best impacts are along and west of I-25 south of the Palmer Divide, so Monument, Colorado Springs, and Pueblo.

In Denver, only a bit over half of this precipitation falls as snow, so just a couple of sloppy inches.

The GEM (Canadian)

The Canadian model has been the most consistently exciting over the past couple days, with quite a lot of precipitation along the urban corridor from Broomfield to Pueblo.

It’s also perhaps the warmest with only half of precipitation falling as snow in Denver. That said, precipitation totals are so high that this is still the snowiest solution, especially south of the Palmer Divide where more of it should fall as snow and double digit totals are forecasted.

The ICON (German)

Well, we’re just throwing this model in here because why not. We haven’t been keeping too good of tabs on its performance this season.

For this system, it looks to roughly straddle the Euro and Canadian solutions, both in terms of temperature and precipitation totals. Denver and the SW foothills / Palmer Divide get the nod for stronger impacts in this model’s guidance as opposed to the Colorado Springs area.

The NAM

Now we’re getting into mesoscale models. The NAM was very spicy over the past couple days but its latest run this evening has settled down quite a bit.

This run has also shifted the bullseye to Colorado Springs and west, with double digit totals. It’s also colder and has most precipitation falling as snow across the Front Range.

Its higher-resolution brother looks to have some very significant pockets of precipitation up in the Denver metro area too, though.

Overall, this model is in line with the aforementioned models.

The SREF Mean

This is an ensemble of higher resolution, mesoscale models such as the NAM, and shows where general sentiment lies. This also doesn’t differ to much from what we’ve seen, and the bullseye lies south of the Palmer Divide.

A bit warmer than the NAM, with a good chunk of precipitation north of the Palmer Divide falling as rain.

The WRF

We’ll take a look at the CAIC’s 4km WRF.

This is perhaps the most exciting solution for the mountains and the Denver area, with well over an inch of liquid precip for many I-70 ski areas and along some heavily populated stretches of I-25.

This is also a very warm solution and less than half of the precipitation that falls in the lower elevations of the Front Range comes in the form of snow!

We’re not sure if we buy the widespread double digit snow totals for the mountains. Under similar setups, this model has overforecasted the mountains.

The Blend

So this takes us to the Blend. We’re expecting something in the middle of all this, right?

Wrong. The Blend is much drier than any of the models above. It’s also significantly warmer with most precipitation along the urban corridor falling as rain. The bullseye is west of Colorado Springs.

The Blend’s snow forecast for Denver is 0-2”, and almost all of that would melt upon contact with the ground.

Here’s another look at snow totals, with some its probabilistic ranges:

So what gives? Ensembles. The models we discussed above were neat and all, but they’re still only a fraction of the amount of model guidance that is out there (over 100 more ensemble members, plus a few other models that we didn’t include). In those ensembles, sentiment has been overwhelmingly towards the dry and warm side of things.

Generally, ensemble means in the Denver metro area have been running 1-6” and trending downwards.

For Denver International Airport, the Euro ensemble mean has trended down to just an inch of snow after hovering in the 2-4” range over the past few days. Same trend on the GFS ensemble.

Usually, with just a couple days to go, we’d weight the deterministic models (all the various models we listed earlier) over the ensembles, but considering guidance can’t seem to decide which side of the Palmer Divide gets the most snow, we still feel like it’s acceptable to lean on the ensembles.

Conclusion

In this case, we’d say – expect a decently wet, but fairly mild storm from Wednesday to Thursday on the Front Range. In terms of snow, areas at a lower elevation than the foothills may struggle to pick up any appreciable amount of it, with low snow-liquid ratios and a lot of melting on warm surfaces.

In the foothills and on the Palmer Divide, totals could quickly jump up, with well over a foot of snow possible in places.

In the mountains areas along and east of the Divide could get 3-8” of snow, but areas west of the Divide may only see Trace to 5”.

For travel in the Front Range, the biggest issue could be Thursday morning, when temperatures may be low enough to start freezing the wet surfaces. Issues will arrive earlier (Wednesday afternoon/evening) at higher elevations.

Next Week: Looking Snowy!

Regardless of what happens with this storm, next week looks quite snowy for most of Colorado’s mountains, with ensembles predicting powder days on Tuesday the 22nd and possibly Wednesday. Stay tuned!