textproduct: Western and Central Wyoming

KEY MESSAGES

- Isolated showers continue overnight through sunrise Wednesday morning across the northwestern parks along with southeastern Natrona County.

- Warming trend Wednesday through Friday with isolated chances for northern mountains Wednesday afternoon to early evening (10-20%).

- Cold front Friday night will bring some precipitation chances for southeastern portions of the viewing area with a more widespread chance with the next system late Sunday into early next week.

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 /06Z TAFS THROUGH 06Z THURSDAY/

Issued at 1045 PM MDT Tue Sep 22 2026

VFR conditions across all terminals to start the TAF period. A few showers may move nearby KJAC, KCOD, and KCPR for the start of the period (06Z-08Z). However, confidence regarding direct impacts at terminals remains low and a brief weakening outflow due to dying showers cannot be ruled out. After 08Z precipitation should dissipate with winds becoming light at nearly all terminals. Conditions will dry out into Wednesday morning with little to no chances for showers. The only exception to this would be KCOD which may see a nearby afternoon/evening shower. Winds remain light at 5 to 10 knots at most terminals by the afternoon with KCPR/KRKS seeing a breeze of 10 to 20 knots develop. Light winds return to all terminals to end the TAF period.

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.