JACKSON, Wyo. – A storm will arrive on Thursday afternoon, bringing snow to the valley just in time for trick-or-treating along with travel impacts over Teton Pass. More snow is possible this weekend and early next week.
Recent Weather
Over the past week, we’ve experienced a late fall temperature roller coaster with an overall trend downward. A brief cool-down with light precipitation during the middle of last week gave way to a mild weekend with highs reaching the 60s in the valley.
Colder air arrived early this week and light snow fell on Tuesday with the Tetons picking up 1-3 inches. Snow fell in the town of Jackson but did not accumulate other than light dustings on elevated surfaces.
Heavier snow fell across Central and Eastern Wyoming, favoring the east side of the Winds and Absarokas, the Bighorn Range, and the Casper area with double-digit snowfall totals.
Winds aloft were predominantly blowing from the northeast, which is favorable for precipitation east of the Continental Divide, but less so west of the Divide in the Tetons – hence the light snow amounts locally. The Tetons do better when winds have a westerly component.
The light snow and cold air are still a reminder that the seasons are changing. While October has been a warm month overall, it’s safe to say that 70-degree temperatures (and probably 60-degree temperatures) are done for the year.
Temperatures were cold enough during Tuesday’s snow event for light snow to accumulate on Teton Pass, resulting in slick and snowy conditions.
The view from the base of Jackson Hole Mountain Resort on Tuesday was a good visualization of the changing seasons with new snow dusting the higher elevations and the last of the fall colors hanging on in the village.
On Tuesday, the high temperature only reached 37ºF in Jackson, which was only the second time so far this fall with a high temperature below 50ºF. This was also the coldest high temperature reading since April 5.
Wednesday has been a similarly chilly day with a high of only 38ºF so far in town as of 3 p.m. Skies have remained mostly cloudy with occasional flurries due to lingering moisture on the backside of Tuesday’s storm.
Next Storm on Thursday
We’re going to have a snowy Halloween this year as the next storm arrives on Thursday afternoon. Snow could begin as early as midday, but will pick up in coverage and intensity during the afternoon hours and will continue into early evening.
This will be a relatively short-duration storm but snowfall rates will be heavy at times, especially over Teton Pass. Snow will easily accumulate on road surfaces near the top of the pass with afternoon temperatures in the low 20s, and gusty winds will limit visibility at times.
Snow will also fall in the town of Jackson and surrounding valley locations on Thursday afternoon and into the evening, right around the time when trick-or-treating will be happening.
Snow will have trouble accumulating in town and in the valley during the daytime hours due to relatively warm temperatures.
Once we lose daylight and temperatures begin to drop, snow will have a better chance of accumulating in town. Then it just becomes a matter of precise timing…
If heavier snowfall lingers well into the evening, then accumulations will likely occur in town. However, if most of the snow ends by sunset (as a few models have recently started to hint at), then accumulation potential will be limited.
Regardless, plan on slow travel over the pass on Thursday evening and also plan on cold, damp, and snowy conditions for trick-or-treating.
Snow accumulations will generally range from a trace to 2 inches in the valleys and 3-6 inches in the Tetons above 8,000 feet, with isolated higher totals possible.
Active Pattern Continues This Weekend and Early Next Week
On Friday, a relative lull in the pattern is expected, but lingering moisture and cold air on the backside of Thursday’s storm will result in mostly cloudy skies and a chance of light snow showers or flurries.
Roads may also be icy over Teton Pass on Friday morning, and possibly on some valley roads as well.
Another storm will move into our area this weekend, though weather models are in poor agreement on the storm track and the resulting impacts.
Snow is possible on both Saturday and Sunday, with the highest likelihood in the Saturday night to Sunday afternoon timeframe. Light to moderate accumulations are possible in the Tetons, with more limited potential in the valleys due to warmer temperatures.
Early next week, another storm is possible around Monday-Tuesday. This storm appears to have a higher ceiling in terms of snowfall potential and temperatures also look colder compared to the weekend, but there is plenty of uncertainty in the details this far out.
Here is a 7-day snowfall projection representing the average of 50 simulations of the European weather model. It’s beginning to look a lot more winter-like across the Western U.S…
We may see a few days of drier weather during the second half of next week with long-range models hinting at a shift back to active weather around November 10 or so.
Alan Smith, Meteorologist
