Jackson Hole Daily Snow
By Alan Smith, Meteorologist Posted 5 months ago October 2, 2023
A strong storm system will impact Western WY on Monday & Tuesday. Heavy rain is falling in the valleys while snow is falling down to 9k feet as of Monday AM. A cold front will move through early Mon evening with snow levels falling to 7.5-8.5k feet overnight & Tuesday. Heavy snowfall of 6-12" will accumulate above 10k feet with a quick drop-off in totals lower down.
Short Term Forecast
Our ongoing storm system has trended stronger since my last post, with the main impacts expected on Monday & Tuesday while Sunday proved to be an appetizer.
We did see several rounds of showers on Sunday along with a few thunderstorms while the higher peaks were dusted with snow. Conditions dried out during the evening, while a surge of deeper moisture arrived early Monday morning with rain and snow overspreading the area since the predawn hours.
Snow levels started out around 10,000 feet early Monday morning, but as of this writing have since fallen to around 9,000 feet. The top of the Teton Lift at Jackson Hole Mountain Resort has a dusting of snow, and this is located just above 9,000 feet.
Taking a look at the big picture, a powerful low pressure system is located over the Intermountain West with the low pressure center currently located in Utah. Significant moisture and energy downstream of this Low is working its way into Jackson Hole and Western Wyoming from the south.
This pattern is also evident when looking at water vapor satellite imagery. The white colors indicate significant moisture in the upper atmosphere, and the counterclockwise "spin" of this moisture around the low pressure center is indicative of significant "energy" moving into Jackson Hole.
Forecast for Monday to Tuesday:
This storm will continue to impact our area from Monday morning through Tuesday evening.
Winds will be out of the south through most of the day on Monday, which will favor the Jackson Hole Valley and eastern side of the Tetons as the shadowing effect of the Tetons will be negated. Teton Valley and the west side will also see rain/snow during the day on Monday but not as much compared to the east side.
Late Monday afternoon/early Monday evening, a cold front will arrive as the low pressure system moves eastward, and winds will shift from southerly to westerly.
A few hours of heavy precipitation can be expected across all areas with the frontal passage. Precipitation will then favor the west side and upper east side of the Tetons later Monday night as precipitation becomes more orographic in nature. However, we'll still have enough energy in the atmosphere for the JH Valley to see more rain showers as well.
On Tuesday, showers can be expected throughout the day with west/northwest winds aloft that will favor the west side of the Tetons with the heaviest and most widespread activity. Showers will be lighter and more intermittent in the JH Valley.
Eventually, showers will taper off on Tuesday evening with conditions drying out by early Wednesday morning.
Snow levels will range from 9,000-10,000 feet during the day on Monday, before falling to 7,500-8,500 feet behind the cold front on Monday night.
Snow levels will remain in the 7,500-8,500 foot range for the most part on Tuesday and Tuesday evening, and could occasionally dip as low as 7,000 feet under heavier showers.
Snowfall will be very elevation-dependent with this storm, and small changes in elevation will result in significant differences.
Here are the snowfall amounts I'm generally expecting by elevation from Monday AM through Wednesday AM:
- 6-12" @ 10k+ feet
- 3-7" @ 9k feet
- 1-3" @ 8k feet
- 0-1" @ Below 8k feet
Snow quality will be wet and heavy with snow-liquid ratios of around 6:1 to 8:1 (1" of liquid = 8" of snow).
Heavy snow can also be expected across the higher terrain in the Gros Ventre, Wind River, Salt River, and Southern Absaroka Ranges, with lighter amounts in the Northern Absaroka, Beartooth, and Bighorn Ranges.
Precipitation amounts (rain and liquid-equivalent snow) from Monday AM through Wednesday AM will range form 1-2 inches in the Tetons and a half-inch to an inch in the valleys.
Highs will only reach the upper 40s to low 50s in the valleys on Monday and Tuesday with lows in the upper 30s to low 40s.
High temps at 9,000 feet will be in the mid 30s on Monday and low 30s on Tuesday with overnight lows in the upper 20s.
Winds will be moderate during most of this event, with stronger gusts expected late Monday afternoon and Monday evening as the cold front moves through.
Occasional lightning activity will be possible on Monday afternoon, and to a lesser extent on Tuesday afternoon. Morning and overnight lightning activity is unlikely.
Snow is expected to fall on Teton Pass during the Tuesday morning commute. Temperatures are expected to be near or just below freezing, so it will be borderline as to whether or not any snow accumulates on the road.
If we do see any road accumulations (and it's a big IF), it will be confined to near the top of the pass and will be on the lighter/slushier side. Still, plan on taking it slow just in case as most of us still have our summer tires on our cars.
Dry and sunny weather will return following this system from Wednesday (October 4) through Monday (October 9) as a ridge of high pressure builds over the Western U.S.
Temperatures will remain chilly on Wednesday and Thursday with highs in the 50s in the valleys, then we will warm up well into the 60s from Friday through Monday, setting the stage for a nice weekend.
The next chance of rain/snow looks to be around mid to late next week, sometime in the October 10th-13th timeframe.
Thanks so much for reading! Next update on Wednesday (October 4).