Jackson Hole Daily Snow
By Alan Smith, Meteorologist Posted 8 months ago May 31, 2023
An active early summer pattern will continue with light showers on Wednesday morning giving way to scattered thunderstorms on Wed afternoon – most likely mid to late afternoon depending on how quickly the AM cloud cover clears. On Thu, we start to see a further uptick in moisture & shower/t-storm chances while the period from Fri to Sun could feature more widespread showers/t-storms.
Short Term Forecast
Forecast for Wednesday:
A minor disturbance is moving through the area on Wednesday morning with a band of light showers moving across the Tetons. This band is weakening as it moves to the east/northeast and some of this rain may be evaporating before it hits the ground in the JH Valley. The band of rain is also passing north of the town of Jackson, where instead of light showers a layer of fog is present.
Here is a view of the shower band moving into the Tetons as seen from Teton Valley.
Satellite imagery reveals extensive cloud cover moving across Eastern Idaho into NW Wyoming this morning, and as a result, we could see additional light showers through the AM hours. The cloud cover will likely delay surface heating needed for thunderstorm development in the afternoon, though just how long the cloud cover persists and delays heating remains uncertain.
If the cloud cover dissipates early enough, then I wouldn't rule out a slight chance of storms by early afternoon, but I think our best chance of storms will be from about 3pm to 8pm.
Storm motions on Wednesday afternoon will be from southwest to northeast, as we will be in between two features – an area of low pressure over the Desert Southwest and a developing trough of low pressure slowly workings its way into the Pacific Northwest.
From a regional standpoint, the most widespread coverage of storms will be to our west and northwest from Central Idaho into Southwest Montana.
However, I'm still expecting thunderstorms to develop across NW Wyoming with the best odds in the Tetons and Yellowstone, while Star Valley and the Wind River Range will see lower odds. Snow levels across the region will generally range from 11,000-12,000 feet.
Storms may be more scattered in nature (rather than widespread), but there is some high-end potential for stronger storms to develop. Strong storms will be capable of frequent lightning, small hail, and gusty winds, so be on guard if heading out during the mid to late afternoon hours.
On the other hand, if our morning cloud cover ends up being more stubborn than expected and persists for most of the day, then it could end up suppressing afternoon thunderstorm development. We will see.
Forecast for Thursday:
We will see an interesting setup as the most eastward area of low pressure moves into Western Colorado, placing Western Wyoming under a south to southeast flow. This will reverse the typical storm motions, with storms moving from south/southeast to north/northwest, or southeast to northwest.
Moisture will also increase overall across Wyoming, favoring areas on the eastern side of the Continental Divide (i.e. east of Jackson Hole) for more widespread showers and thunderstorms along with potential for heavy rain. While the Tetons are west of the Divide, much of Yellowstone is along and north/east of the Divide so the threat of heavy rain will be higher up there too.
In the winter time, southeast winds are typically less favorable for precipitation in the Tetons. But when dealing with convective precipitation (i.e. thunderstorms and showers that develop due to instability in the atmosphere typical in spring and summer), this largely overcomes this negative effect.
As a result, I'm expecting we'll see some showers and thunderstorms reach Jackson Hole and the Tetons as well, though with comparatively less coverage compared to areas further east. There is also a chance we could see strong storms in the Tetons, capable of producing frequent lightning, small hail, and heavy rain.
The highest threat of storms will be during the afternoon hours, but showers and storms couldn't be ruled out in the morning either. Also, the strength/coverage of thunderstorms versus showers (without lightning) will be somewhat dependent on how much flat cloud cover we see early in the day.
Snow levels will generally range from 11,000-12,000 feet with freezing levels of 12,000-13,000 feet, similar to recent days.
Forecast for Friday to Sunday:
This continues to look like a wet period for our region as multiple low pressure areas track into the Central Rockies with an abundance of moisture contributing to rain and thunderstorms. The day-to-day details are uncertain and will hinge on a number of factors such as wind directions and cloud cover, the latter of which will influence instability and how much lightning we see as opposed to just rain.
While the afternoon and early evening hours will see the highest coverage and potential for rain, we will probably see some showers during the overnight and morning hours as well. So it will definitely be a weekend where you'll want to pack rain gear.
Temperatures will also be a bit cooler overall during this period with increased moisture, though the source of the moisture will still be from warmer/subtropical regions and snow levels will remain high as a result.
Outlook for Next Week (June 5th-11th):
We may dry out somewhat early next week compared to the weekend, but overall an active pattern will remain in place with daily chances of showers and thunderstorms, especially during the afternoon hours.
Thanks so much for reading! Next update on Thursday (June 1).