JACKSON, Wyo. — In classic Wyoming fashion, the Memorial Day holiday weekend is going to kick off with well below average temperatures along with wet conditions and even some snow for the lower elevations. The culprit will be a powerful low pressure system that will move across the Northern and Central Rockies on Friday and Saturday.
Showers will arrive early on Friday morning, especially farther north in Yellowstone where the heaviest precipitation will fall initially. Areas above 7,500 ft. in Yellowstone can expect to pick up 2-4 inches of snow on Friday morning.
Jackson Hole will be right on the edge of the shower activity through Friday morning with scattered showers expected, whereas areas south of Jackson should stay dry through lunchtime. The focus of heavier showers will gradually shift south into Jackson Hole on Friday afternoon with the rain/snow line around 7,500-8,500 ft.
Highs on Friday will only reach the upper 40s in the Jackson Hole valley.
Jackson Hole will then see its heaviest precipitation fall during the overnight hours Friday night and continuing through Saturday morning.
Snow levels will fall to 6,000-6,500 ft. in Jackson Hole on Saturday morning, so we could very well wake up to snowflakes falling in the town of Jackson. In the Grand Teton National Park valley, light snow accumulations will be possible on Saturday morning, especially above 6,500 ft., and snow potential will only increase heading north into Yellowstone.
Rain and snow showers will persist into Saturday afternoon with the rain/snow line ranging from 6,500-7,500 ft., before eventually tapering off sometime on Saturday evening. Highs on Saturday will only reach the mid 40s in Jackson — about 20 degrees colder than average.
The higher elevations of the Tetons are going to see a good late season dump out of this storm, with total snow amounts from early Friday morning through Saturday evening ranging from 8-16 inches above 8,500 ft.
Total liquid-equivalent precipitation amounts from this storm will range from 1-2 inches in the Tetons and Yellowstone and 0.5-1.25 inches in the Jackson Hole and GTNP valley.
The good news is that the second half of the holiday weekend is looking better. Sunday will be more an in-between day — while conditions will be drier overall, scattered clouds and cool temperatures will linger and there is a slight chance of light rain showers. Highs will reach the mid 50s in Jackson.
The last day of the three-day weekend will be the nicest day as conditions finally dry out with increasing sunshine. Temperatures will be warmer as well with highs reaching the low 60s in Jackson.
There is also more good news next week. Starting Tuesday, the warm-up will continue with highs getting into the 70s in the days to follow!
Alan Smith, Meteorologist