Winter Storm Update | Dec. 11-12, 2020
Second phase of the storm begins: again, fairly modest snow totals. We continue to see a cold, unsettled, but disappointing pattern in the future.
Our first phase of the storm panned out over the past 24 hours about as expected. Notable exceptions include Vail, which picked up about 7" in spots (and was favored for a bullseye on some models — thanks to one of our readers for alerting us to the nice totals there) and the high Sangres (near the Sierra Blancas) which picked up 8". We also looked to have had Wolf Creek sneak in some nice totals at the last second from a small but strong band of convective snow, bringing their 5" total from this morning up to 13" — wow!
You can check out our breakdown that we posted on social media this morning, and in general, we did see an extra inch or two over the day besides a few small bands that set up for areas like Wolf Creek, the Crestones, and parts of the West Elks.
Over the past 24 hours, models have continued to push our next storm on Saturday evening (not really a “phase”) further southwest, as we suspected may happen. This will give us weaker left and more westerly (even a bit southwesterly) flow for a majority of the storm. Snow totals for the northern mountains will on the lower end of our initial projections, and it also looks like the prospects of banded snowfall are considerably lower.
Check out the position of the jet from the latest run (left/top), vs. 30 hours ago (right/bottom):
In our last forecast, we said that, barring any strong banding:
On Saturday from noon to midnight, we can expect 3–6" of additional fluffy snow across the northern mountains, Sawatch, and eastern San Juans, 4–8" for the western mountains and Steamboat, 1–3" for the foothills, and 0–2" for Denver.
This still generally holds true, but we have some tweaks. With the storm tracking further south, a northerly to north-northeasterly upslope will have a better chance of setting up over Denver for a few hours. Moisture looks to be a bit more readily available than we saw previously, so we’re willing to bump Denver’s forecast up to about 1–4", though likely on the lower end (median: 2"). Totals will only be an inch or so higher for much of the foothills.
With the more westerly / west-southwesterly flow progged for the mountains, we need to make some adjustments:
- Wolf Creek should receive more snow from this event. We’ll give them a 5–10" snow forecast (median 7"). Silverton will also do well — the forecast is the same. Note that the probabilistic forecast still has 3–4" as the potential low end in both these forecasts, so there is some bust low potential.
- The west side of the San Juans, up to the Elks, should receive some good snow — Telluride and Crested Butte should get into the 4–8" range. (Taos, NM should also be in this range — good wind direction, though they don’t spend as long as long under the lift). It’s worth noting that the despite the setup, the high-resolution models have been very cynical about the Aspen resorts, so we’ll drop them to 3–6".
- The 3–6" forecast remains for Vail, Breck, Copper, Keystone, A-Basin, Loveland, Winter Park, and Steamboat (now likely too far north for a 4–8" forecast). We should hit near the upper end of this range for most mountains, with the median at about 5".
Temperatures are looking quite cold above 11,000ft., so bundle up if you’re headed out this weekend. Ridging doesn’t look to establish as strongly on Sunday and Monday, so temperatures wont recover much from the more frigid conditions we’ll experience over the next 36 hours.
There are more storms in the forecast, but none of them look particularly exciting.
Monday night features yet another southwesterly flow event:
This storm is pretty starved of moisture, so we don’t expect more than, generally, a couple inches in the mountains.
By the end of the week, or possibly later next weekend, we have another signal for a potential storm.
Doesn’t look that impressive, does it?
We do see the PNA dip before the holidays, along with a stormy signal in the ensembles, so that unfortunately may be the next distant hope for a good storm…
Still, enjoy the snow. Cheers.
Forecast by
Thomas Horner
@highpointwx
https://highpointwx.com
