textproduct: Western and Central Wyoming

KEY MESSAGES

- Wind speeds decrease Monday evening under a mostly clear sky. This allows for cooler Tuesday morning lows of 26 to 32 in the far west valleys and basins, while other lower elevation locations generally drop to between 36 and 42.

- Tuesday will be mostly dry, with any isolated late day showers confined to the southern-third of the state.

- Increasing moisture arriving from the southwest Wednesday allows for a better chance of showers and thunderstorms during the afternoon and evening. This trend continues through at least Friday as seasonal temperatures prevail.

UPDATE

Issued at 100 PM MDT Mon Sep 14 2026

IR continues to depict clearing skies behind the system that pushed through last night. Gusty winds in its wake continues, especially through the Absarokas to the Cody Foothills still pushing 40 to 50 mph. 30 to 40 mph will be common across the wind corridor from eastern Sweetwater to Natrona Counties where the Red Flag Warning remains for the rest of the afternoon and evening hours. Winds will diminish towards sunset with radiational cooling under mainly clear skies. This will bring the coldest start to the morning for Tuesday but with a slight warming trend for the rest of the work week. The next system still on track with no major changes that will push in Wednesday night west of the Divide before pushing to the east that will bring scattered storm chances for much of the CWA Thursday and Friday. Stay tuned for details in the coming day or two going forward.

DISCUSSION

Issued at 240 AM MDT Mon Sep 14 2026

In last night's discussion, I made a reference to a rather old song from the 80s. Tonight, we are going even further back, to when I was a little kid, the 1970s. And this song, and this band, are very appropriate for today, at least after any showers end shortly after sunset. The song is September, and the band is Earth, Wind and Fire. Meaning on earth (at least in western and central Wyoming), the wind impacts today will be from wind and fire, and it is occurring in September. Just not on the twenty first night, but on the fourteenth day of the month.

The culprits for this are an upper level low now spinning over northern Idaho that will move eastward today. Most of the moisture should be gone by shortly after sunrise, with dry weather returning for the entire area after that. The low will be close enough to keep a decent pressure gradient across the area as well. A jet streak will be moving across the northern portions of the state as well. All this adds up to a rather windy day across most of the area. Most of western and central Wyoming has at least a 2 out of 3 chance of wind gusts over 30 mph today, with a greater than 1 out of 2 chance of gusts over 45 mph in the windier portions of the area. As for the high wind warning, we will leave it up, but it looks borderline. The best chance would be in areas like near Clark and to the west of Cody, where there is around a 1 in 2 chance of wind gusts over 55 mph. There is still the chance of a mountain wave in places like Cody and possibly Dubois or even Lander, but not enough confidence to add to the warning. The strongest wind in the north should be over by around noon, but gusty wind will continue through the day before decreasing tonight as the jet streak moves away and the atmosphere decouples.

The other concern is fire weather. There will certainly be plenty of wind across the area, so that is a slam dunk. The area for low humidity also looks solid, covering areas mainly south of the Owl Creek and Bridger Range as well as Sweetwater County. If there is a mitigating factor, it is that some areas received a decent rain tonight, which should wet fuels at least initially. It has been spotty though, so we will keep it as is. Elsewhere, relative humidity should remain above critical levels. However, elevated fire weather will be likely everywhere as most locations will see humidity under 25 percent this afternoon. As for temperatures, it will be cooler behind the front, with highs fairly close to seasonal normals for the middle of September.

Tuesday looks like a fairly quiet day for most with sunshine mixing with some clouds. Some increased moisture may try to return to far southern Wyoming and could bring a stray shower or thunderstorm. Most activity should hold off until after sunset though. Moisture may push through the southern third of the area to bring a spotty shower or thunderstorm, but most areas will not see one.

The reasoning for the rest of the week remains similar to the past couple of days. And upper level low will move from the Pacific Northwest to the northeast and eventually to the east. There is a bit of more model consensus this morning in taking the low over Montana late in the week rather than into Wyoming. However, there are still some differences in the exact position as well as the speed in which it moves through. Southwest flow will keep some monsoonal moisture moving into the area, as well as bring a return of above normal temperatures. With the increased moisture, there will be a chance of showers and thunderstorms each day from Wednesday through Friday and possibly into Saturday as well. At this point, Thursday and Friday may be the most active days. However, there is still a ton of model spread regarding the placement of timing of the most numerous showers and storms. As a result, we kept largely broad brushed the POPs. At this point, drier air looks to return for the second half of the weekend.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 506 PM MDT Mon Sep 14 2026

VFR conditions prevail through the period. Winds gradually decrease this evening, between 00z and 04z at most sites. Lighter winds and a clear sky occur overnight. Increasing high clouds move in Tuesday, with western sites and KCPR seeing west to southwest winds gusting around 20 to 25 knots during the afternoon.

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

FIRE WEATHER

Issued at 240 AM MDT Mon Sep 14 2026

Much drier air will move into the area today with any showers ending early. In much of Natrona, Fremont and Sweetwater County, a gusty to strong wind will combine with humidity falling below 15 percent to bring critical fire weather this afternoon. Elsewhere, humidity should remain above critical levels. However, a gusty wind will bring periods of elevated to near critical fire weather, especially in the afternoon.

RIW WATCHES/WARNINGS/ADVISORIES

Red Flag Warning until 8 PM MDT this evening for WYZ279-280- 283-289-300.

Freeze Warning from 3 AM to 9 AM MDT Tuesday for WYZ023.