JACKSON, Wyo. – Aside from an increasing threat of rain showers on Sunday, the next week looks spectacular across the region with highs in the 70s and lows in the 30s, along with plenty of sunshine.
Recent Weather
Last week, a slow-moving low pressure trough resulted in several rounds of showers and thunderstorms moving through the area. A quicker-moving disturbance also brought rain showers on Sunday night and Monday.
Teton County has not had any single widespread heavy precipitation events yet in September, but measurable rain has been recorded in the town of Jackson on 8 out of 17 days so far this month.
So far this month, the town of Jackson has received 0.80 inches of rain, and Jackson Hole Mountain Resort (Raymer Plot) has received 1.53 inches of rain.
Temperatures have been trending cooler as well. We have had three mornings in which temperatures fell below freezing in Jackson. Also, on Monday and Tuesday, highs were only in the 60s, which is only slightly below average but a sign of the changing seasons.
For perspective, the average high and low on September 17 are 72º and 35º, and by next Wednesday (September 24), the average high and low are 69º and 33º. These are based on the previous 15 years (2010-2024).
The higher elevations of the Tetons were also dusted with snow as showers moved through during the past week. This was most noticeable on Monday morning when a heavier coating of snow was observed above 11,000 feet.
Upcoming Weather Pattern
The second half of this week, from Thursday to Saturday, will feature near-perfect weather. Daytime temperatures will warm up a bit from prior days with valley highs well into the 70s, while mornings will still be chilly with lows in the 30s (dipping to near freezing in some areas).
It will be a great time to get out and enjoy the trails with comfortable temperatures and good trail conditions (not too wet and not too dry).
The one day we could have inclement weather over the next week is on Sunday, and the culprit will be the remnants of Tropical Storm Mario in the Eastern Pacific Ocean.
A disturbance will arrive from the southwest on Sunday, and moisture from this tropical system will reach our area, resulting in a chance of scattered showers and thunderstorms.
The best chance of showers is expected on Sunday afternoon and Sunday night, but the timing of this could still change, so make sure to pack rain gear if you head outdoors on Sunday. Also, be aware of the risk of lightning, especially in the afternoon.
Given the tropical origins of the system, no major cooldowns are expected other than what occurs due to cloud cover. Highs are still expected to reach the upper 60s to low 70s in the valleys while snow levels are projected to start around 12,000 feet before lowering to 10,500 feet later Sunday night.
It’s possible we could see some lingering clouds and showers into Monday morning, depending on the timing of the disturbance.
However, a drying trend is then expected from later Monday into the middle of next week with increased sunshine and highs in the 70s.
Here is a 7-day precipitation outlook, which accounts for Sunday PM-Monday AM rain potential in our area.
Overall, it looks like an outstanding week, other than Sunday’s scattered showers. The leaves have quickly started to change recently as well, and the fall colors will only continue to get better over the next couple of weeks.
Long-term, there are some hints of a possible weather system arriving toward the end of next week and into the weekend of September 27-28, but confidence is low. Also, there are still no major fall cold fronts anticipated for now, but at some point, that is inevitably going to happen.
Alan Smith, Meteorologist
