Weather Lookup

Key Messages

- a warmer day for most today. Isolated to scattered (15-40%) thunderstorms this afternoon and evening, mainly in southern and western wyoming. The strongest storms could have very small hail and gusty outflow winds.

- greater chance of showers and storms thursday and friday, with friday having the most widespread chances. Brief moderate to heavy rain is possible.

- temperatures remain near to above normal through friday, with cooler temperatures for the weekend. Drier weather returns by sunday.

Update

Issued at 1154 AM MDT wed sep 16 2026

The light showers from this morning, and the associated cloud cover, has mostly exited to the east. With a mostly sunny sky, isolated to scattered (15-40%) showers and thunderstorms are expected to form during this afternoon, mainly for western and southern wyoming. Most of this activity dissipates this evening, with some lingering overnight across the far south as moisture continues to advect northward.

Discussion

Issued at 216 AM MDT wed sep 16 2026

Have you ever had someone that overstayed their welcome, be it at a party or staying at your house? Well, the weather is doing that again. Our friend the monsoon (which those of you who read my discussions know i love so much, note sarcasm) has returned. And will be around for a few more days.

We do have some shower and isolated thunderstorms around as i write this, but nothing strong and the storms are moving. Monsoonal moisture will continue to push northward today and increase the coverage of showers and storms across the area. Coverage still looks scattered at best though (at most a 1 out of 3 chance). There is decent model consensus in keeping a vast majority if the showers and storms along and west of the continental divide and also near casper. We can't rule a shower or storm out anywhere, but the chance is only around 1 in 10 or less. As for potential flooding, probably not through wednesday night. The core of the deepest moisture should remain south of wyoming today. There is also some steering flow, about 15 to 20 knots worth, which should keep the showers and storms of the moving and not of the stationary variety. As for temperatures, this looks to be the warmest day of the week with flow turning to south and still some sunshine. Some of the warmer spots will likely see highs around or over 80 degrees.

Coverage should increase on thursday. An upper level low will slowly approach from the pacific northwest. At the same time, a strong ridge over the southeast will begin to retrograde to the west and direct deeper moisture into the area, as much as 175 percent of normal. At the same time, a weak shortwave will be pivoting around the upper level low giving a bit more lift. However, there is a limiting factor. It is that with the moisture in the atmosphere, much of the day may end up being fairly cloudy. This may limit instability somewhat, especially since it is now mid september and not july, limiting daytime instability. Nevertheless, there will be an increased chance of showers, especially across western wyoming. With the increased cloud cover, temperatures will also be cooler, generally by about 5 to 10 degrees compared to wednesday.

The upper level low will begin to make a closer approach by friday. Of all the days, this looks like the most active day across the area with almost all areas having at least a 1 in 3 chance of convection during friday and friday evening. I have one more concern about this day as well. Most guidance is showing a 20 percent drop in precipitable water. However, this could lead to a fairly sunny morning that could bring more instability and a greater chance of convection, especially east of the divide. If there could be local flooding, this could the most likely day. The one mitigating factor continued to be steering flow though, as much as 40 knots at times. So the storms will be moving. And with more sun, temperatures will be warmer, but likely not as warm as today.

The low will pass close to the area on saturday, turning flow more to the northwest. This should result in a noticable cooler day across the area. There will still be enough wrap around moisture for some showers and isolated thunderstorms to continue. However, most guidance shows precipitable water values much lower on this day, so the threat of heavy rain looks less. Uncertainty then increases from sunday into early next week. As a lot depends on the movement of the upper low. Some guidance moves it far enough east for drier weather to move in for sunday, other guidance keeps showers around through sunday night. Confidence is not high in specifics as the models have had different solutions in regards to speed and track of the upper level low for the past few days. However, we do have high confidence of unsettled weather through at least saturday. Somewhat drier and warmer weather may then return for early next week.

Aviation — 18Z Tafs Through 18Z Thursday

Issued at 1130 AM MDT wed sep 16 2026

Breezy winds are anticipated at kcpr and krks the first part of the taf period. Scattered showers and thunderstorms are forecast across wyoming this taf period, with impacts possible (30 percent chance) at krks, kriw, klnd, kpna, and kbpi wednesday afternoon and evening. Chances at kjac this afternoon are less than 20 percent due to the forecasted shower activity likely remaining over the nearby mountains. Overall dry conditions are expected overnight at all terminals with relatively light winds. Showers and thunderstorms are forecast as early as 14Z thursday at krks and after 16Z thursday around kcpr and kpna, with chances at other terminals increasing after 18Z thursday. Localized MVFR flight conditions and gusty winds cannot be ruled out in any shower or thunderstorm. Occasional mountain obscurations are possible due to increasing cloud cover.

Please see the aviation weather center and/or cwsu zdv and zlc for the latest information on smoke, icing, and turbulence forecasts.