textproduct: Western and Central Wyoming

KEY MESSAGES

- Elevated to critical fire weather conditions persist for portions of mainly central and southwest Wyoming this week due to gusty afternoon west to northwest wind 25 to 40 mph and minimum relative humidity in the teens.

- Freezing temperatures occur across the western valleys and basins early Wednesday morning, with the coldest locations seeing lows between 24 and 28. Sensitive outdoor plants are likely to be impacted by temperatures below 28 degrees.

- Daytime high temperatures remain near seasonal normals through the week, with minimal chances for rain.

- Confidence continues to increase for a storm system to arrive this weekend. An initial cold front pushes across the region Friday afternoon and evening, setting the stage for cooler and wetter weather Saturday and Sunday.

UPDATE

Issued at 1153 AM MDT Tue Sep 8 2026

The main changes with this update are the addition of Freeze Warnings and Fire Weather Watches, as it is that time of year where the duality of fire and ice exists in Wyoming. Starting with the freezes, temperatures over the western Wyoming valleys and basins are again expected to drop below freezing (32 degrees F) tonight. Many places this morning saw mid-20s to mid-30s. With little change in the forecast compared to last night, another night of widespread freezes are expected. Impacted locations include the Green River Basin, Jackson and Star Valleys, and the lower elevations of Lincoln County. Sensitive plants will likely see frost or freezes tonight into Wednesday morning.

Fire Weather Watches have also been issued for fire zones 277, 278, and 279 for Wednesday afternoon and evening, which includes the Green River Basin, Sweetwater County, southern Lincoln County, and Uinta County. Minimum humidity will be under 15 percent for these areas, with afternoon winds around 25 mph. Red Flag Warnings continue to be in effect for portions of central Wyoming.

DISCUSSION

Issued at 210 AM MDT Tue Sep 8 2026

Clear skies are in place across the CWA this morning and will be the norm for the next few days. This will help temperatures to drop this morning, in addition to the cooler airmass in place in the wake of yesterday's cold front. Freezing temperatures will be possible in the more cold-prone locations west of the Divide, like Jackson, Pinedale and Hoback Junction. Dewpoints are around 27 degrees as of 07Z (1am), with nearly calm winds so would not be surprised if temperatures drop below freezing in these areas. Dewpoints are slightly higher in Star Valley, around 32 to 34 degrees at Afton and Alpine so temperatures look to stay just above freezing.

The trend this week will be the dry conditions along with breezy winds, along with seasonal temperatures and mainly clear skies. Red Flag Warnings are in effect again today across areas east of the Divide, from the Cody Foothills to the Wind River Basin and over Natrona County. West winds, with gusts of 25 to 35 mph, will be widespread across much of the CWA again this afternoon. Eastern portions of the Bighorn Basin and most of Johnson County will be the exceptions. A second cold front will reach northern portions around 00Z and quickly push southward through the evening hours. The front will be dry, as there is no available moisture in place after yesterday's cold front.

Wednesday will be the calmest day of the week. Seasonal temperatures will remain in place and the winds will not be as strong as today or yesterday. West winds with gusts up to 30 mph will be mainly confined to more wind prone locations, mainly from southern Lincoln County to Natrona County. Red Flag Warnings will be likely in these areas, as critically low RH values become widespread. Stronger winds return for Thursday, with widespread gusts of 30 to 40 mph occurring for most areas. Daytime temperatures will also be slightly above normal for areas east of the Divide. Another cold front will move over the area Friday, causing another day of gusty winds of 30 to 40 mph impacting much of the CWA.

Models continue to trend toward a strong cold front impacting the Cowboy State this weekend and have come more inline wrt timing. Confidence is medium for widespread precipitation ahead of the system on Saturday. If there is any snow with this storm, it would be confined to the northwestern mountains and the northern end of the Bighorns Sunday night into Monday morning.

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/

Issued at 950 PM MDT Tue Sep 8 2026

All terminals to be VFR through the entire forecast period within dry west-northwest aloft. Little more than late day scattered mid- cloud over the far north. Wind speeds are less than 10kts overnight before daytime mixing allows for westerly surface 11-22kts to increase between 19Z-21Z/Wednesday at KCPR and terminals west of the Continental Divide. KRKS will likely see afternoon gusts 25-30kts. Some late day 9-13kt west-northwest winds surface for a few hours at KRIW and KLND. All winds decrease between 01Z-03Z/Thursday as the atmosphere decouples.

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

FIRE WEATHER

Issued at 210 AM MDT Mon Sep 7 2026

West winds with gusts of at least 25 mph and critically low RH values will occur in various locations today through Thursday. Red Flag Warnings are in effect this afternoon for areas east of the Divide. Winds will shift to southern portions of the state Wednesday, as critical RHs become widespread. Thursday will have the strongest winds, with gusts of 30 to 40 mph occurring in most zones. Another cold front will move through the area Friday, but RH values are expected to range between 16 and 25 percent.

RIW WATCHES/WARNINGS/ADVISORIES

Freeze Warning from 2 AM to 9 AM MDT Wednesday for WYZ013-023- 025>027.

Fire Weather Watch from Wednesday afternoon through Wednesday evening for WYZ277>279.

Red Flag Warning until 9 PM MDT Thursday for WYZ280-289-300.