The past week featured cool and unsettled weather across the Jackson Hole region, though some areas did better than others in terms of rainfall. High temperatures in Jackson were in the 50s to low 60s for most of last week, until Sunday when temperatures shot up into the low 70s.
Despite several days in a row of unsettled weather, the “hit-and-miss” showers were more miss than hit for the town of Jackson, where only 0.18 of rain was recorded over seven days. Areas north, south, and west of Jackson saw much higher rainfall amounts, including Jackson Lake where 0.77 inches of rain fell and Afton where 0.79 inches of rain fell.
Areas above 9,000 ft. in the Tetons picked up just over an inch of precipitation over the past seven days, including 6-8 inches of new snowfall. Settled snow depths remain close to average for this time of year as the spring melt continues.
Weekly Weather Outlook — May 18-25
A warm and mostly dry start to the week will give way to a significant cool-down over the second half of the week along with wet conditions as two systems move across Western Wyoming from Wednesday through Friday. We should then see a gradual trend toward drier and more pleasant weather from Saturday afternoon through the remainder of the holiday weekend.
Monday will be warm and dry across Jackson Hole with highs reaching the 70s, but moisture at the upper levels of the atmosphere is being driven north into Wyoming by a strong area of low pressure near the Pacific Coast. This is resulting in persistent thin, high clouds and overcast skies.
Tuesday will be our last warm day and we may even see some pockets of blue skies. On Tuesday afternoon, we’ll also see a slight chance of showers or thunderstorms, but coverage will be isolated and any rain will be light.
The big change will arrive on Wednesday morning as the first storm system swings into Jackson Hole from the southwest, ushering in much colder air with numerous showers developing during the afternoon.
Periods of showers will continue from Wednesday night into Thursday morning will falling snow levels. We could even see some snowflakes fall in the town of Jackson on Thursday morning, with a better chance of snow in the valley areas north of town, especially in GTNP and Yellowstone. Higher elevations above 9,000 ft. could pick up 2-6 inches of snow from Wednesday through Thursday morning.
We should see a relative break in the action on Thursday afternoon, then a second storm system will drop in from the northwest on Friday, leading to a good chance of rain showers throughout the day and into the night.
As we kick off the holiday weekend, don’t be surprised to see some snow reaching the valley floor with showers that linger into Saturday morning — especially north of Jackson.
While Saturday will remain chilly with some lingering rain/snow showers early, we should see a warming trend on Sunday and Monday with decreasing rain chances, though some isolated shower chances couldn’t be ruled out on Monday as some moisture tries to sneak into the area.
Moving forward — I will post an updated holiday weekend weather outlook on Thursday. Since next Monday is Memorial Day, the weekly weather update for next week will be posted on Tuesday instead of Monday.
Alan Smith, Meteorologist