textproduct: Western and Central Wyoming

KEY MESSAGES

- Isolated showers across northern portions of the area dissipate around sunset this evening.

- Dry and warmer conditions are expected Thursday through Saturday with mostly clear to partly cloudy skies. Southwest winds will become stronger and gusty (15-25 mph) Friday and Saturday.

- Sunday will see increasing clouds with isolated showers over the northwest WY mountains. Winds will remain breezy from the southwest in the afternoon and evening.

- A storm system is expected to move through western and central WY late Sunday through early Tuesday, bringing precipitation to much of the area along with cooler temperatures in the 50s and 60s to start out the week. Warmer and drier weather then moves in during the middle of next week.

UPDATE

Issued at 118 PM MDT Wed Sep 23 2026

The shortwave trough that brought isolated to scattered showers and thunderstorms yesterday has moved northeast overnight and is now over southeast Montana. Lingering wrap-around moisture in west-northwest flow has kept cloudy skies over the mountains of northwest and northern WY, including some morning showers. Isolated showers are possible (10-25%) over the northwest WY mountains, the western Bighorn Basin, and the north-central Bighorn Mountains this afternoon through sunset. The probability of precipitation forecast for these areas was increased slightly and extended in time. Gusty and breezy winds with 15-25 mph gusts will continue across parts of southern and central WY, as well as over the higher terrain, through about sunset. Skies will clear after midnight, allowing temperatures to drop Thursday morning (compared to this morning). The previous forecast remains on track for the next few days as well (warming, drying, and windier Fri and Sat) before the next storm system develops late Sunday into Monday.

DISCUSSION

Issued at 100 AM MDT Wed Sep 23 2026

IR continues to show the open wave moving northeast out of the CWA with the colder cloud tops into Montana and northeastern portions of the state. Improving skies are pushing in from the southwest that will lead to ample sun for Wednesday. WV shows the main finger of the PFJ well to the north into Canada extending from a low over the Gulf of Alaska. Some isolated rain showers persist as depicted on radar, mostly across Yellowstone as well as for southeastern parts of Natrona County. These will dissipate and push northeast by sunrise Wednesday morning with no impacts expected and limited accumulations.

Another weak mid level trough skirts to the north for Wednesday afternoon and evening that will bring some isolated storm chances for the northern Absarokas and Bighorns (10-20) with limited hazards to have an affect. These will dissolve by sunset losing its instability with radiational cooling heading into the overnight hours Wednesday night. Diurnal winds across the wind corridor will see some weak gusts up to 20 to 25 mph but most will remain relatively light for Wednesday afternoon. Beyond that, expect a slight warming trend for the remainder of the work week with weak induced ridging building in from the south and southeast with increased convergence aloft extending into the state. As this occurs, the aforementioned GOA low starts to push southeast towards the Pacific northwest becoming more of an opened L/W trough as it progresses towards the upper Rockies. Come late Friday evening and into the overnight hours, it will skirt to the north dropping a cold front through the CWA into Saturday morning. Limited moisture in the lower levels expected with this more progressive system to the north, but some interaction with moisture further southeast will bring sporadic shower activity from eastern Sweetwater to Natrona Counties through mid-day Saturday. Winds increase with this system, but nothing out of the ordinary for Wyoming standards with gusts up to 20 to 30 mph in many areas and a bit more for the wind corridor in the same areas of showers.

More seasonable temperatures heading into Sunday ahead of the next wave for late evening and into the overnight hours for the new work week ahead. Longer term model solutions bring continued cooler temperatures than currently to be more seasonable for this time of year heading into the later days of September. A more widespread precipitation chance is possible but no distinct solution is being agreed upon with the models. Stay tuned for updated forecasts in the coming days.

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 434 PM MDT Wed Sep 23 2026

VFR conditions prevail through the period. Any breezy winds decrease this evening, with light winds overnight and into Thursday morning. A few light showers across northern Wyoming for the first two hours of the TAF period. Once these showers dissipate this evening no precipitation is expected through Thursday afternoon.

RIW WATCHES/WARNINGS/ADVISORIES

None.