JACKSON, Wyo. – Sunny skies and warm temperatures will prevail late this week with highs in the 70s from Thursday to Saturday. Starting on Sunday, shower and thunderstorm chances will enter the picture, with cooler temperatures and periods of valley rain and mountain snow in the days to follow.
Recent Weather Conditions
The first week of May has featured warmer-than-average temperatures and several mild and sunny days. On Saturday, the high temperature hit 72ºF in Jackson, which is our warmest of the year so far.
However, we did see a brief stretch of wet conditions as a storm system moved across the Western U.S.
On Sunday, scattered showers and thunderstorms developed in the afternoon, ultimately producing only light rainfall amounts along with strong winds.
On Monday, a more potent wave moved through our area from the south/southeast, bringing a longer-duration period of heavy rain and snow that lasted for several hours in the afternoon and evening, along with a sharp drop in temperature.
After reaching a high of 62ºF early on Monday afternoon just before the rain began, temperatures eventually fell into the 30s in Jackson by late in the day. Rain even changed to wet snow in town for a bit as heavy precipitation rates caused freezing levels to dip lower than expected.
Although snow fell in town, it never accumulated to more than a slushy trace on grass and elevated surfaces as the air temperature remained above freezing. Once precipitation rates eased in intensity a bit, snow turned back to rain in town.
Overall, Jackson received 0.72 inches of precipitation (including melted snow) during Monday’s event, which is our second-highest daily precipitation total so far this year.
Heavy snow also fell in the mountains, with accumulations of 5-9 inches in the Tetons above 8,000 feet, while the top of Snow King received 2 inches of snow.
Aside from Monday’s storm, mountain snowpack receded at a faster rate than normal during the first week of May, and snowpack in the Upper Snake River Basin is 93% of average (slightly below average) as of May 7.
Current measured snow depths in the Tetons as of May 7 range from 75 to 95 inches at 9,500 feet and 48 to 55 inches at 8,000 feet, though this varies by location depending on aspect and sun exposure.
Upcoming Weather Pattern
A ridge of high pressure will dominate the weather pattern from now through Saturday, resulting in beautiful weather conditions with abundant sunshine and warmer temperatures.
As of mid-afternoon Wednesday, temperatures are in the low to mid 60s around Jackson. Further warming is expected from Thursday to Saturday with highs reaching the 70s. Saturday looks like the warmest day of all when we could reach the mid 70s.
There is a slight chance of a late-day shower or thunderstorm on Thursday as a disturbance passes north of our area, but any rain will be light and spotty. Friday and Saturday look totally dry.
The weather pattern will begin to change on Sunday as a trough of low pressure approaches from the west. Sunday will be another warm day with highs reaching the 70s, but the uptick in moisture will lead to an increase in cloud cover with a chance of showers and thunderstorms in the afternoon.
Temperatures will start to trend cooler from Monday on as the trough works its way inland, with the highest chance of rain expected around mid-week (May 13-15 window), though the timing is subject to change this far out.
Temperatures will trend colder over time, and there is a good chance of snow in the mountains during this pattern. It wouldn’t be a huge surprise if wet snow occasionally mixes in with rain in Jackson and the lower valley, either.
From sunny and 70s to cold and wet with rain and snow… classic May weather in Jackson!
Cooler and wetter conditions could potentially stick around late next week and into the weekend of May 17-18 as well, with NOAA’s 8-14 day outlook favoring below normal temperatures and above normal precipitation.
Alan Smith, Meteorologist
