Colorado Weather Forecast | Feb. 8–14, 2021
Windy, with snow during much of the week and likely a stronger event into next weekend.
- Windy today and tomorrow, and likely for much of the next week
- Arctic air mass looks to be locked up just north and east of the urban corridor — but it will splash the I-25 corridor with cold air throughout the week with a full intrusion possible by the weekend
- Continuous but fairly weak snow event from Tuesday to Friday
- Larger storm likely from Friday to Sunday, very uncertain, could potentially impact Wolf Creek the most if model trends continue but likely a western CO event with good NW flow on the backside into Monday
It’s beginning to look a bit like December up in Colorado’s northern mountains! Northern and central Colorado have pulled some decent totals over the past few days. The forecast we issued from Friday to Saturday did pretty well…
…with the exception of areas east of the Divide, where the flow was strong enough to pull decent snow into the higher terrain to the east, and most notably, the major underperformance in Aspen. This was due to some significant dry air entrainment on Friday night which reduced the available moisture.
Even then, the higher reaches of the Elks were still able to get some serious snow thanks to enhanced orographic lift. The weather station near Highlands Bowl recorded over 9" of snow from Friday to Saturday, while Aspen Highlands resort only reported 2".
Unsurprisingly, the Park Range has gotten the most snow in the state over the past five days, with reports of new snow accumulation in excess of four feet up by Buffalo Pass. Areas as far south as the northern San Juans have benefited considerably from this storm, with the other region of highest totals being the Elk Range.
Here’s how snow depth has changed across the state since Wednesday. Note that this accounts for compaction, sublimation, and melting. For instance, Vail has reported 29" of snow since Wednesday, but their SNOTEL site’s snow depth change between Wednesday morning and today is 13", thanks to compaction and winds.
The wind is already doing quite a number to this fresh snow. The same jet stream that helped deliver the snow has also been responsible for the high winds during the storm, into today, and likely into next week.
The jet stream is currently ripping over north Colorado and Wyoming, which is bringing some fierce wind gusts down to the surface.
RTMA shows gusts well over 60mph along the Divide from Wyoming into New Mexico, as well as for Colorado’s higher ranges west of the Divide. You can also see strong gusts touching down east of I-25 courtesy of the strong mountain wave east of the Divide.
The mountain wave is exactly that — a wave. Though high winds are rampant around the western metro, gusts are not as ferocious as they could be, as the wave isn’t quite touching down. It is having better success in the eastern plains after it undulates over Denver.
Some of the most impressive gusts we’ve seen recorded have been at Winter Park (115mph near the top of Pano), Breck (98mph at the top of Peak 8), and Niwot Ridge (89mph).
There’s also a frontal boundary in far northern and eastern Colorado:
Temperatures are MUCH colder to the north and east of this front. This is the edge of the arctic air mass that we have mentioned in our previous forecasts.
The weather prediction center has this front becoming stationary a bit west of its current position for much of next week — this means it should be easy for cold air to slosh in and out of the urban corridor over the coming week.
We think “sloshing” is an apt description for what is occurring:
Denver’s proximity to this significantly colder air results in a temperature chart that looks like this, thanks to the high amount of uncertainty surrounding surface level conditions:
The uncertainty bounds for Wednesday’s daytime temperatures are almost 20 degrees wide. Will it be a fairly decent day, or crisp and wintry? Regardless of how this shakes out, there will definitely be parts of eastern Colorado that will experience very cold weather over the next week, with light snow mixed in with the frigid temperatures.
The Week Ahead
For much of the next week, the polar jet remains just to our north, forming a boundary between us and the deep mass of arctic air over Canada.
On Tuesday, a weak trough forms over California and passes over Colorado by Thursday.
Upper level flow is messy, but it’s possible we’ll see some lift ahead of this wave as the jet right entrance region becomes more pronounced.
As the trough passes over the state, we should get an additional bit of lift from the jet max behind it, though this looks a bit questionable and short in duration.
Perhaps our best asset will be moisture, which looks to be plentiful for this entire event. It will just be a matter of picking up good large scale lift to turn it into snow.
Flow looks to be southwesterly to west-southwesterly during much this event, depending on how much the trough deepens and how far south it tracks. As the trough passes overhead, winds turn more northwesterly and banded snowfall is possible as winds aloft strengthen.
Right now, the best moisture and lift looks to be in central Colorado. There doesn’t look to be a robust enough southerly component for this to be a Wolf Creek event — instead, western Colorado resorts will likely do best. Highest totals by Thursday afternoon look to be in Telluride, Silverton, Crested Butte, the Aspen resorts, Vail/BC, and Steamboat, but widespread snow will fall and conditions should be soft across the Colorado mountains as we get later into the week.
We’re seeing the first part of this storm impacting the west side of the northern and central mountains from Tuesday morning to Wednesday morning, with west-southwesterly flow. Wednesday morning could be soft in the Park Range (4–12"), Flat Tops (4–12"), and near Crested Butte (4–15"), with possibly some decent totals in Vail (3–7"). Winds turn more southerly into Wednesday morning, amplifying snow in the Elks, West Elks, Grand Mesa, and San Juans, while drying things out over the Front Range and Summit County.
Widespread snow decreases into Wednesday night, with banded snowfall becoming the main precipitation feature on Thursday morning. This looks to mainly impact central and northern Colorado before light to moderate orographically induced snowfall under northwest flow becomes the main feature on Thursday night and into Friday. Friday morning could feature soft conditions in north and central Colorado.
The snow forecast looks to still be heavily in flux, with widespread disagreement, so we wont be posting a map that is likely to be substantially incorrect. Instead, look at our timings and distributions that we’re thinking of above, and check the website for an updated view of snow expectations and certainty, and we’ll post more clear expectations tomorrow.
Friday may be the end of the previous trough’s influence on our weather, but things look to remain active.
A weak wave of some sort looks likely on Friday night. This would amplify the already existent northwest flow, perhaps with some decent (though not epic, unlike the I-70 traffic) totals for northern Colorado on Saturday morning.
A much stronger wave will possibly end the weekend, though plenty of disagreement exists at this point (the GFS has almost continuous snowfall through the entirety of the weekend, though ramps it up on Sunday with the stronger wave). Looking at how the models have been tracking this system, we wouldn’t be surprised if they decided on additional digging and had this impact Colorado as another epic event for Wolf Creek and the San Juans, though that’s not the current guidance. Right now, flow looks a bit more likely to be benefit most of western Colorado, with nice northwest flow behind it. In that case, the powder day would be on Monday.
Down on the plains, it looks possible but not probable that these upper level dynamics will be enough to let the arctic air to our northeast infiltrate all the way to the east side of the Divide. The GFS finally has us in the grips of arctic air by the end of the week:
While the Euro has it perpetually locked up further into the plains behind the stationary front, with only minor splashing:
Overall, flow is messy, and models have been in serious disagreement on mid atmospheric dynamics, so please take this weekend’s forecast with a huge grain of salt, and we certainly wont attempt to forecast snow totals for it. The upside looks good, but it doesn’t seem to be the most likely solution when looking at a cross-section of the ensembles:
We’ll provide an update tomorrow for a better picture on mid-week snow expectations.