Colorado Weather Forecast | Jan. 18–24, 2021
Weather pattern continues to look more active, but largest totals are still confined to the San Juans and Sangres.
Summary:
- Significant snow for Wolf Creek tonight and tomorrow morning
- Unsettled, cold weather elsewhere
- Warmer and dry on Wednesday and Thursday
- Increasing cloudiness and unsettled weather on Thursday, especially in western CO
- Complex flow from Thursday to Monday — snowfall generally favors the western and southern mountains
- Significant snow for Wolf Creek again from Saturday to Sunday and likely early next week
- Decent signal for strong, but not necessarily snowy storm early/mid next week
Light snow continues to fall this morning in the central and northern mountains as a weak shortwave last night produced a couple inches of snow for many ski resorts — with the exception of some areas near the Continental Divide, where up to 6" fell by this morning thanks to a focused shot of orographic lift at higher elevations within a couple dozen miles of Berthoud Pass (A-Basin, Loveland, and Winter Park are reporting 5–6").
These resorts are actually experiencing pretty decent skiing conditions thanks to the shortwave previous to this and some wind-drifted snow. If you ski the resorts near the Divide, you should always keep an eye on snow stake cams for these northwest flow shortwave events as there are often surprises! We generally shy away from trying to predict these — for instance, if we went off the model data last night, we would’ve had Steamboat as the most likely place to pick up a surprise 6"+ (they only picked up 2").
We turn our attention to a more serious storm that will impact southern Colorado tonight. In the 48 hours since our last forecast, the ECMWF has forecasted the cutoff low to have slightly more favorable movement and positioning for enhanced snowfall in the southern San Juans. The largest gains in snow totals for areas like Wolf Creek compared to a few days ago are due to the more prolonged nature of the storm, as large-scale lift looks to hold on until late Tuesday evening.
Unfortunately, the overall placement of the low (too far to our south and west) isn’t a good setup for impressive totals in the San Juans — but 12 hours of moderate snowfall will surely stack up.
For once, the deterministic snowfall forecast and median ensemble precipitation forecast both agree with each other on blended probabilistic products, putting down about 10" of snow for Wolf Creek, most of which will fall from midnight tonight through noon on Tuesday.
Both the ECMWF and short range models have tightened Wolf Creek’s snow forecast into a 9–16" range and provide roughly a 25% chance of exceeding 12".
We’ll issue the following forecast for ski resorts most likely to benefit from this storm. This is from tonight through Tuesday at 11pm:
- Wolf Creek: 10–14"
- Taos: 6–12"
- Purgatory: 6–10"
- Silverton: 3–6"
- Monarch: 2–6"
- Telluride: 2–5"
You’ll notice a decent forecast for Taos — much of the Sangres and Wet Mountains look to pull a decent upslope from the east, in addition to the southern Sangres (Culebra Range into New Mexico) getting a decent shot of westerly upslope as well.
This weak easterly upslope will be in place all the way up to northern Colorado— with the foothills west and south of Denver likely picking up some light snow tonight / tomorrow morning. It’s possible, but unlikely, for much of the metro to pick up an inch of snow with the foothills picking up another inch or so — but it’s more likely that little more than flurries will fly north of the Palmer Divide.
Not a lot of snow is expected in the mountains north of US-285, though the weather will be cold, cloudy, and unsettled, with light snow and lows generally in the single digits and highs in the teens or low 20s through Tuesday. A few resorts along I-70 could pick up a few inches by Tuesday morning — so not a complete bust, but not enough to warrant a more detailed forecast.
On Wednesday, that mid-atmospheric low continues to sit off the coast of southern California, but ridging builds around it, rebounding temperatures in Colorado for the day. A jet to the north of the state looks to bring subsidence into Colorado, shutting off the snowfall.
Highs in the metro area will be in the 50s, with temperatures in the 20s and 30s in the mountains below treeline.
The ridging breaks down on Thursday, and a fairly complex upper-level wind pattern sets up over the state as the aforementioned low begins to move east, a few disturbances drift past the north of our state, and a strengthening low over the Pacific Northwest further perturbs the jet stream in the proximity of Colorado. These features are shown below, with the red lines along axes of a couple passing shortwaves, the black arrow showing the path of the weakening storm system from Monday, and green circling the new strong storm that will form.
Ultimately, all this action doesn’t look to do much more than interfere with the upper level flow, and large-scale lift doesn’t set up in any significant or organized fashion until the new storm over the Pacific Northwest begins to strengthen and dig south early on Friday. Westerly to west-southwesterly flow will provide snow opportunities for much of the mountains on Friday and Saturday, with highest totals in western Colorado.
Unfortunately for snow lovers in northern Colorado, this new storm looks to follow the exact same track as our current storm — it is forecasted to strengthen and dig south to the Pacific Ocean just off the coast of southern California, positioning the jet over Colorado which will provide southwesterly flow. Wolf Creek could very well see another two feet of snow between Thursday and Tuesday, with accumulations likely over 12" from this event on Friday through Sunday.
As we’ve seen with these setups, the ensemble median is much more cynical, with only about 10–15" of snow for Wolf Creek from Thursday to Tuesday and 8–12" of snow on Saturday and Sunday. We’ll keep an eye on this, but if you’re looking to chase powder next weekend, Wolf Creek remains an easy bet. If you’re looking to stay closer to the metro area, the resorts that do well under westerly flow (Steamboat and Vail) look to be decent choices.
Our map of snow accumulations from Thursday to Sunday doesn’t look impressive, but as it is a blended product, this is largely due to uncertainty in the models. We expect the snow forecast increase significantly as we get closer to the end of the week. We do agree with the overall distribution of highest totals on this map, with the notable exception of Wolf Creek, which looks to be under forecasted.
Finally, we are seeing a large, strong storm signal on the ensembles around the middle of next week, though on the deterministic models it doesn’t appear to set up appreciable large-scale lift to produce big snow totals —instead, much colder temperatures are the more likely scenario.
We’ll post an update in a couple days as the weather pattern to end the week and start the next week begins to resolve. We continue to see a stormy pattern, but as you can see, it typically resolves in storms that are less than ideal for northern Colorado. Let’s hope we can buck that trend sometime soon.
Forecast by
Thomas Horner
@highpointwx
https://highpointwx.com
