JACKSON, Wyo. – During the first 10 days of December, three to five feet of snow fell above 8,000 feet in the Tetons. However, an extended dry spell is underway for mid-December with no indications yet of when consistent snowfall may return.
Snowfall During the First 10 Days of December
Following an underwhelming November, an active pattern took hold across the Tetons during the first 10 days of December with two major storm cycles occurring.
Snow totals so far this month include 65 inches at Grand Targhee, 50 inches at Jackson Hole Mountain Resort’s upper mountain, 36 inches at Jackson Hole’s mid-mountain, and 24 inches at Togwotee Pass.
Grand Targhee, in particular, benefited from a storm last Friday in which light to moderate northwest winds and cold air aloft resulted in favorable orographics (terrain-enhanced precipitation) on the west side of the Tetons, with 17 inches of low-density snow recorded in 24 hours. Skiing conditions were fantastic as a result.
Snowfall totals across the lower elevations so far in December include 8 inches in Jackson, 10 inches at Jackson Lake/Moran, and 12 inches in Teton Village
Snowpack (the amount of snow on the ground) is about 90% of average across the higher elevations of the Tetons, which is a significant improvement from two weeks ago. However, the percent of average snowpack is likely to decrease in the coming days if not weeks.
The recent snowfall has helped Jackson Hole Mountain Resort and Grand Targhee to open up more ski terrain after a slow start to the season. Snow King was also able to open last Friday, though terrain is limited there with shallow snow cover.
Warm temperatures in between storm cycles (and in some cases during the storms) have resulted in low snow cover in the valley relative to average. So far this December, temperatures are running 7.7ºF above normal in the town of Jackson and 6.2ºF above normal at Jackson Lake/Moran.
The town of Jackson has yet to see the temperature dip below zero this season. By this time last season, we had already experienced 13 days with subzero low temperatures.
Current Dry Spell May Last for a While
Just when it seemed that snow season was starting to pick up, a dominant ridge of high pressure has taken hold across the Western U.S. this week, resulting in clear and dry conditions in Western Wyoming.
This ridge of high pressure will remain in place through at least the weekend, with only a slight chance of a weak storm sneaking into our area on Monday or Tuesday of next week (continued dry weather is the more likely scenario, however).
A temperature inversion is expected to gradually take hold over time with colder temperatures in the Jackson Hole Valley compared to the mountains. However, temperatures are still not expected to be particularly cold in the valley compared to what we often see at this time of year.
From Wednesday through Sunday (and possibly beyond), high temperatures are expected to reach the 30s in the mountains and 20s in the valley, with overnight lows in the 20s in the mountains and single digits in the valley.
When Will This Dry Spell End?
That is the million-dollar question. Starting next week, an active pattern is expected to develop along the West Coast, favoring California. However, early indications are that the main storm track will set up too far south heading into the holiday period.
Here is an 8-14 day projection from NOAA, which indicates probabilities of above or below-average precipitation. Jackson Hole is right on the edge between “below normal” and “near normal”.
Based on medium to longer-range weather models, it is likely we will see some snow during the 1-2 week time frame, but the outlook doesn’t look favorable for significant or frequent snow.
There is also a strong signal indicating a continuation of above-average temperatures heading into the holidays – not only in the Tetons but for just about the entire country.
Keep in mind that while forecasts 1-2 weeks out can give us some clues to the big-picture pattern, these forecasts are always subject to change as confidence is inherently lower this far in advance.
Thanks for reading! I will not be writing weekly weather articles for the next two weeks with the busy holiday season ahead. Check back in for my next weekly post in early January and Happy Holidays!
Alan Smith, Meteorologist
