textproduct: Western and Central Wyoming

KEY MESSAGES

- Slightly cooler today, with highs in the upper 50s and lower 60s.

- A weak weather system to the south brings increased clouds across southern Wyoming through this evening, with a very low chance (10%) of a virga shower.

- Another weak system moves across western Wyoming on Tuesday, with chances (30-40%) for rain showers.

UPDATE

Issued at 1234 PM MDT Sun Oct 18 2026

The forecast remains largely unchanged with this update. Mostly sunny conditions continue today, with highs slightly above normal. A few virga showers remain possible (10%) around Sweetwater County through late today, associated with a little mid-level moisture, evident by the clouds on satellite.

DISCUSSION

Issued at 220 AM MDT Sun Oct 18 2026

Ridging begins to flatten today as the next coastal trough begins to dive southward along the West Coast. Light north to northeast winds behind yesterday's weak front and the decrease in the ridge will keep temperatures much closer to normal today, with highs mainly in the upper 50s to mid 60s. A weakening trough tucked in ahead of the larger west coast trough will move into western Colorado this afternoon, spreading a few more clouds into southern WY. There may be just enough moisture to spark a shower or two, but surface humidity remains particularly dry still, so likely will only see a few virga showers this evening across Sweetwater County.

Monday will see an increase in moisture, but with little to no upper level support, not expecting anything more than a few clouds across SW WY during the afternoon.

Tuesday with the trough stalling off the California Coast, southwest flow aloft will continue to bring some more Pacific moisture into western WY. There may be enough diffluence aloft for a few showers for the western mountain ranges during the afternoon, but wringing any moisture out of these will be a hard task.

The coastal trough finally ejects northeast into the Rockies by Thursday. Still varying differences in model solutions regarding where it finally goes, but in any case, there will be some precipitation Thursday into Friday, mainly for areas west of the Divide.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 1137 AM MDT Sun Oct 18 2026

VFR conditions are expected through the period. Wind will remain light under 10 knots, with skies mostly clear other than some high clouds.

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.