textproduct: Western and Central Wyoming

KEY MESSAGES

- Mostly clear skies and seasonable temperatures overnight into Monday as passing clouds push east of Sweetwater County into the morning hours.

- A weak system pushes across Tuesday with isolated shower activity (~20%) across higher terrain, mainly west of the Divide. No significant impacts expected.

- Seasonable temperatures with modest winds through much of the week with the next bigger system by week's end Thursday night into Friday and over the weekend. Details are of low confidence currently.

DISCUSSION

Issued at 130 AM MDT Mon Oct 19 2026

IR currently depicts mainly clear skies into Monday morning with some passing clouds through Sweetwater County pushing east by sunrise. Water vapor shows weak upper level southwest flow across the CWA with the main finger of the PFJ well to the north supporting a low off the Pacific northwest coast. This will deepen with its southward progression Monday into Tuesday with increasing divergence aloft. Seasonable temperatures and relatively light or modest winds 10 to 20 mph through mid week expected. A weak shortwave will propagate across the southwest flow Tuesday afternoon and evening that will bring isolated shower activity for higher terrain, mainly west of the Divide. Low coverage is expected ~20 percent with no significant impacts expected.

As the aforementioned low starts to move east across southern California Wednesday, models indicate it becoming more of an open and more progressive wave. This will then push along the southwest flow across the upper Rockies not of high of an impact with its quicker movement. However, models are not in the best of agreement and QPF amounts fluctuate with each model run. With this run, it has bumped up for mountain snow, especially for western mountains but does include the Bighorns. With the seasonable to just above temperatures, expect valley/basin rain, even west of the Divide below 8-9kft. This will be the biggest weather event to keep an eye on for headlines going forward for late Thursday into Friday, stretching into the weekend, all dependent on how quickly it progresses with its east to northeastward movement. Beyond that, induced ridging will be short lived ahead of another low off the Pacific northwest extending in from the GOA that could be more impactful with a more reinforced colder air and lower freezing levels. Stay tuned for updated forecasts in the coming days, but enjoy the quieter weather leading up to later in the work week.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 430 AM MDT Mon Oct 19 2026

VFR conditions expected for the entirety of the period at all TAF sites. Mainly clear skies and relatively light winds around 10kts or less, outside of a slight breeze at CPR in the afternoon due to daytime heating and mixing to the surface. Increasing mid level clouds for JAC towards sunset and overnight after 02Z with an approaching weak wave clipping to the northwest of the CWA. Otherwise, dry conditions with no other weather elements expected.

Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on smoke, icing, and turbulence forecasts.

RIW WATCHES/WARNINGS/ADVISORIES

None.