textproduct: Western and Central Wyoming

KEY MESSAGES

- October starts off with pleasant dry weather and slightly above seasonable temperatures.

- Warmer and breezy Friday with elevated fire weather likely (2 out of 3 chance) from eastern Sweetwater County through Natrona County.

- Above normal temperatures continue through much of next week with only small chances for any showers.

UPDATE

Issued at 1145 AM MDT Thu Oct 1 2026

Little to update regarding the previous forecast discussion. October is starting off quite pleasant with dry conditions, near seasonable temperatures and plenty of sunshine. Friday is looking quite warm with highs forecast to be 10 to 15 degrees above normal. Model guidance is showing most basins east of the Divide such as the Bighorn and Wind River Basins having a 40-70% chance of seeing highs reach 80F. Locations west of the Divide see warm temperatures as well with highs getting into the low to mid 70s. Near elevated fire weather conditions do remain possible Friday mainly along the Wind Corridor from Rock Springs to Casper. Otherwise, not much else to add forecast wise with a brief cool down for Saturday. A prolonged period of above normal temperatures in association with a large ridge moves over the western CONUS for the end of the weekend into the start of next week. Record daily high temperatures may be in jeopardy for Monday with highs possibly getting into the low 80s east of the Divide. These warm temperatures look to persist through much of next week as a potent ridge remains locked in place across the western CONUS.

DISCUSSION

Issued at 1233 AM MDT Thu Oct 1 2026

Welcome to the final quarter of the 2026. And if there is a rule of thumb for the past nine months, it is that has been a very warm year on average. Most of our major climate sites have had either their warmest or second warmest year on record so far this year. And most of the next several days will be more of the same.

There are some minor concerns to worry about. The main feature of the day is a weak cold front that will drop southward into the northern Wyoming today. There is not a ton of moisture to work with and the best jet forcing should remain in Montana. There may be just enough moisture and forcing for a stray shower over the Bighorns or Johnson County, but the chance is generally 1 out of 6 or less, with most locations remaining dry. There will also be a bit of a breeze in that location, but nothing out of the ordinary. Otherwise, it will be another dry and nice autumn day, although somewhat cooler East of the Divide.

On Friday the concern shifts to fire weather. Another weak cold front will be approaching from the north. Flow will turn southwesterly ahead of the front, bringing downsloping flow and a warm day, with some locations seeing high temperatures rising into the 80s in the warmer spots. With the tightening pressure gradient, a gusty breeze will develop in the favored southwesterly flow areas from eastern Sweetwater County to Natrona County. As for potential fire weather highlights, there will be enough wind. However, humidity looks borderline at best. The NBM ensemble gives a mean minimum humidity generally only around 18 to 22 percent even in the favored areas, and it may not occur for three hours. So, no fire weather highlights at this point. There will likely be elevated fire weather for a time in the afternoon in the favored locations. Otherwise, it will be another dry and warm day.

Saturday will see temperatures all back a bit East of the Divide following the frontal passage. Like today's front, it has little moisture to work with so few or no showers are expected. There will be a somewhat tighter pressure gradient though, especially across the northwest flow / cold advection areas. The NBM ensemble gives at least 1 out of 2 chance of wind gusts over 30 mph, with a 1 in 2 chance of gusts over 40 mph in northern Johnson County. Fire weather should remain below critical though as cooler temperatures and higher humidity move into the area.

Sunday looks like a dry and mild day with few concerns. Another weak system then approaches Monday into Monday night and could bring a few showers. but again chances are small, generally less than 1 out of 4 in any locations and mainly in western Wyoming. There will likely be more fire weather concerns at times next week, with Monday looking like the day of the most concern with breezy conditions and low humidity developing with the southwest flow ahead of the system. Much of next week looks like a continuation of above average temperatures and little chance of rain as ridging controls the weather across most of the western United States.

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/

Issued at 345 PM MDT Thu Oct 1 2026

VFR conditions expected at all TAF sites for the entirety of the period with mainly clear skies. Winds will diminish from less than 10kts to less than 5kts towards sunset after around 02Z with radiational cooling through the overnight hours into Friday morning. Winds increase after 18-20Z with daytime heating and mixing to the surface up to 18kts for all but RKS/CPR, expecting up to 25kts through the end of the period. These will diminish once again towards sunset into the next TAF cycle. No other weather elements are expected at this time.

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.