textproduct: Western and Central Wyoming

KEY MESSAGES

- Warm, dry, and windy conditions with mostly clear skies will continue from Wednesday into Thursday. Afternoon high temperatures will be just above normal (Wed) to 5 to 10 degrees above normal (Thu).

- Elevated to critical fire weather conditions persist for portions of central and southwest Wyoming from Wed to Thu due to gusty afternoon west to northwest wind 20 to 35 mph and minimum relative humidity in the teens. Thursday will also see critical fire weather conditions spread to the Wind Rivers, Dubois area, Owl Creeks, and Absarokas.

- A weak disturbance from the Great Basin will bring increased clouds with a slight chance of showers Friday morning to the early afternoon across southern and central WY.

- Confidence continues to increase for a storm system to arrive this weekend. An initial cold front pushes across the region Friday evening, setting the stage for cooler and wetter weather Saturday and Sunday, especially east of the continental divide. At this time, precipitation forecasts remain on the light side however.

UPDATE

Issued at 120 PM MDT Wed Sep 9 2026

Forecast remains on track for very warm, dry, and windy conditions this afternoon and Thursday. Thursday looks to be a more widespread day with slightly stronger afternoon winds, and RH values dropping a couple percentages more compared to Wednesday. Have added the east side of the Wind Rivers, the Absarokas, and the Owl Creeks to the Red Flag Warning for critical fire weather conditions as well, especially at elevations below about 9-10 K feet. Humidity recovery is expected to be fair to poor tonight in these areas as well, which will create more hazardous conditions on Thursday.

After a night of clear skies tonight, high clouds are expected to move into western WY Thursday afternoon in advance of a distrubance from the Great Basin. This system should bring enough moisture with weak instability for some light showers over southwest WY early Friday morning. Another system will move across Montana, increasing clouds over northern WY late Friday, and dropping a cool front east of the divide Friday evening. Models are showing an interesting pattern development for WY Saturday and Sunday, but synoptic scale differences are curious at this time, as only light precipitation is expected Satruday afternoon into Sunday morning.

DISCUSSION

Issued at 223 AM MDT Wed Sep 9 2026

A Freeze Warning remains in effect for the western valleys, the Upper Green River Basin and southern Lincoln County this morning. Temperatures of 26 to 32 degrees are expected again in these areas, with more cold prone locations possibly dropping as low as 22 degrees.

Otherwise, dry conditions, clear skies and seasonal temperatures will be in the forecast again today. The main hazard will once again be fire weather. The lightest winds of the week are expected today, however elevated to critical fire weather conditions will be in place due to critically low RH values and wind gusts up to 25 mph. These winds will be primarily located from southern Lincoln County to Natrona County through the afternoon. The Fire Weather Watch that was issued for these areas has been upgraded to Red Flag Warnings as a result. Have also extended these new warnings into Thursday. Burning of any kind is highly discouraged due to the very dry conditions, regardless of how light the winds might be.

Critical fire weather conditions will become more widespread across the CWA again Thursday, as winds increase. Wind gusts of 25 to 35 mph will return for most areas in the afternoon. Exceptions will be for locations like eastern portions of the Bighorn Basin and northern portions of Johnson County. These winds will return for Friday afternoon as well. The main difference will be another dry cold front will move across northern areas east of the Divide. Initial indications are this front will become stationary along southern portions of the Bighorn Basin and Johnson County by midday Friday. Models remain split whether the front will push further southward through the overnight hours Friday and allow for the associated cold pool to infiltrate into the Bighorn Basin and Johnson County.

Moisture will begin to increase Saturday ahead of the incoming storm system, with the western mountains and central portions of the CWA having the best chances for precipitation Saturday afternoon into Saturday night. Snow levels will stay around 10kft through the night, so hunters/backcountry enthusiasts should prepare for snow. The storm itself will move over the Cowboy State during the day Sunday, with the coldest air staying over northwestern portions. Snow levels will range between 7000 and 8500ft in this area and most of the precipitation will stay over northern portions of the state. Freezing temperatures will return to western portions Monday and Tuesday mornings in the wake of this system, with readings in the middle 30s to lower 40s elsewhere. Monday will be a crisp autumn day, with highs in the 60s to near 70s degrees under mostly clear skies.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 1120 AM MDT Wed Sep 9 2026

VFR conditions prevail at all western and central Wyoming terminals through 18Z/Thursday. Given the dry, west-northwest flow aloft, precipitation is not a concern over the region. The main aviation hazard will be gusty westerly surface wind. KCPR and west of the Continental Divide terminals see gusty westerly wind develop between about 19Z-21Z/Wednesday. KRIW and KLND see late afternoon west- northwest wind 10-20kts. These winds drop to less than 10 kts between 01Z-03Z/Thursday. KCPR, KCOD, and KRKS could see an earlier return of the gusty westerly surface wind Thursday, with 12-25kt speeds developing between 15Z-18Z/Thursday.

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 120 PM MDT Mon Sep 7 2026

Update: A Red Flag Warning has now been issued for portions of the Wind Rivers, Absarokas, and Owl Creeks for Thursday from noon to 900 PM. RH recovery will be poor tonight in the lower elevations of these zones, and afternoon humidity values will drop to 12-15 percent accompanied by wind gusts over 30 mph.

Previous Discussion: Fire Weather Watches in zones 277/278/279 have been upgraded to Red Flag Warnings and have been extended into Thursday. Winds will be the lightest across the area today, with gusts of 25 mph occurring from zone 277 to 280/300 and the mountain zones 285, 286 and 288. RH recovery will be fair to poor for most zones tonight. The only areas will good recovery will be zones 140/278 and the Jackson/Star Valleys.

Winds will increase across the area Thursday, with gusts of 25 to 35 mph occurring across most zones. The exceptions will be zones 275, 282 and the northern half of 281. RH recovery will be fair to poor again for most areas again Thursday night. Another cold front will move over northern WY Friday morning and looks to become stationary along southern portions of the Bighorn Basin and zone 281 by midday. Wind gusts of 25 to 35 mph will once again be widespread, however RHs are forecasted to be just above the critical threshold.

RIW WATCHES/WARNINGS/ADVISORIES

Red Flag Warning from noon to 9 PM MDT Thursday for WYZ286>288.

Red Flag Warning until 9 PM MDT Thursday for WYZ277>280-289- 300.