San Juans: Telluride, Red Mountain Pass, Silverton, Coal Bank Pass, Purgatory, Wolf Creek
6am New Snow
6am Powder Potential
Denver and surrounding suburbs: Lakewood, Westminster, Aurora, Highlands Ranch
6am New Snow
6am Snow Accum. Chance
Forecast Discussion - Summary
A complex pattern is unfolding across the western United State this week and promises to bring arctic air and consistent snowfall to Colorado.
Due to the ongoing snow, complexity of the pattern, and duration, we wont get too far into the details of each day. By Thursday, most mountains in Colorado should have a foot or two of new snow (or more! – Wolf Creek), and many Coloradoans will likely be seeking a reprieve from the frigid weather.
And we mean that! This another storm that goes well off the bottom of the “temperature anomaly” scale:
Denver may not see temperatures above freezing from Monday night to Saturday morning!
It’s nice to see us breaking into the upper end of our color scale again!
Here’s the basic breakdown:
Monday: A transitionary period. Snow gets started in western and northern Colorado in the morning. By Monday night, many mountains in Colorado will start seeing heavier snowfall, with lighter or less widespread snowfall further east (Summit County and the Front Range). A strong cold front starts pushing down the Front Range by the morning.
Tuesday: Likely a powder day in the San Juans and parts of the central/western ranges, such as near Aspen. Possibly a bit of a lull in the morning before snow increases in intensity and coverage by later in the day.
Wednesday: Decent snow continues in the mountains. That night, the potential for some northwesterly flow (better for Summit and Grand counties).
Thursday: Snow tapers off by the afternoon or evening.
In general, flow will be primarily southwesterly, which favors the San Juans and the western ranges. However, there is pretty decent jet streaking overhead during much of this event which means we should see strong bands of snow make it all the way to northeastern Colorado, which could help ski areas along I-70 (like in Summit County) keep up a bit and help drive some extra snow on the Front Range to supplement the otherwise shallow upslope there.
Still, Summit County / near the Divide is where the biggest bust potential is. You can certainly see that on a map showing the percentile spreads for various areas:
Here’s a look at snow timings, with a focus on various mountain passes, in case you’re trying to travel in the mountains this week. In general, if you haven’t left by Monday afternoon, you’re going to have a bad time. Tuesday morning offers a bit of a break, but Tuesday evening to Wednesday night looks very difficult.
La Veta Pass
Rabbit Ears Pass
Red Mountain Pass
Wolf Creek Pass
An upper level trough is dropping into the western United States, and is already impacting our weather. A shortwave to the south of this trough will eject into Colorado on Monday night. Lift ahead of this disturbance will be responsible for increasing snow coverage and intensity into the day.
We’ll also be watching for a cold front which will be pushing south and knocking temperatures back in the Front Range by the afternoon. The very coldest air will likely be locked up to the north of the Cheyenne Ridge, but still, this will usher in Arctic air which will be in place for several days.
As for precipitation, we can see that snow chances generally increase through the day, starting in northwestern Colorado.
On the Front Range, we should see snow start filtering in around 4-5pm. In terms of upslope snow, we’re not impressed, but we could see some very strong jet-induced bands of snow that have jumped the divide (much like the past few storms).
Models are very undecided about the timing and coverage of these – the NAM model has the Front Range (from Denver to Fort Collins) getting wrecked by banded snowfall at 6pm, while the HRRR doesn’t have much at all until almost midnight.
For a general feel of snow totals by Tuesday morning, here’s a map:
This is actually pretty close to high resolution model guidance, which is great to see. It seems hard to believe that totals on Tuesday morning wont be much lower than the higher end of the forecast for areas like Wolf Creek, and generally we’re expecting some nice totals across most of western Colorado.
As a shortwave ejects over Colorado, we should see snow rates tick down a bit on Tuesday morning.
Still, if you’re trying to sneak into the mountains that morning, we can’t rule out a few nasty bands of snow still lingering over the state – the NAM model has one almost directly over I-70 on Tuesday morning.
Upper-level dynamics will creep back up during the day along with another wave of moisture. With a jet max overhead, we could see some very serious jet-induced banding (perhaps a snow squall warning?) by the evening. Once again, the western and southern mountains, particularly the San Juans, are favored.
The Front Range could have some weak upslope snow going (which would mostly only impact the foothills significantly), but again, any strong banding could jump the Divide and bring a few inches to the high plains. Otherwise, this isn’t a particularly good setup for serious snow totals in much of the urban corridor.
Tuesday’s high temperatures will be bitter! This wont improve much until Friday.
We see some of the best dynamics and moisture of this entire pattern on Wednesday, and heavy snow will be the primary feature, particularly in the San Juans. Banding will continue to be a major factor for snow production in northern and eastern Colorado, with model guidance setting up several waves of banded snowfall throughout the day and into Thursday morning, some of which impact the Front Range.
Northwest flow finally arrives by Thursday morning, but without any moisture and poor upper-level support (widespread subsidence in the jet left entrance region), the northern mountains may not be able to squeeze more than a couple inches of snow out on Thursday.
Here’s what the leadup to the weekend looks like – we can see a pretty classic NW flow signature. It’s quite possible these totals will come up as we get closer, but at this point, uncertainty around the finer details of the pattern is quite high.
Some model guidance is showing light to moderate snow over the weekend, but nothing substantial. This snow generally looks to favor central Colorado.
We’ll be updating you throughout the week with more details for this ongoing storm. There’s quite a lot going on and we just don’t have the resources right now to really be putting out those detailed exact point forecasts for every ski area, but we’ll try to get into specifics as the week unfolds. Shouldn’t matter too much – there will be good snow to be had most everywhere!
More frequent updates on Twitter, Instagram, and Facebook:
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