textproduct: Cheyenne

KEY MESSAGES

- Dry conditions and above average temperatures will continue through the work week.

- A pattern change is increasingly likely beginning around this weekend into early next week, but the details remain uncertain.

SHORT TERM /THROUGH WEDNESDAY NIGHT/

Issued at 1205 PM MDT Tue Oct 6 2026

Another day of anomalously warm conditions across SE Wyoming and the Nebraska Panhandle, with multiple locations expected to see record high temperatures for this time of year. We remain under upper-level ridging in a quiescent pattern, with a 100 knot polar jet located well to our north over the Canadian Prairie provinces, resulting in mostly dry conditions over our area. Current mid-level water vapor imagery shows a weak disturbance located over Central Utah, with proximity radar indicating some showers over the region and some elevated instability above 600 mb on the 12Z KSLC sounding. The bulk of the forcing for ascent associated with this low-amplitude shortwave trough is expected to remain mostly to our south over Colorado as the wave lifts north and east, however cannot rule out a few high-based showers over the Snowy and Sierra Madre Ranges later this afternoon. Forecast soundings south of the I-80 corridor in Wyoming indicate inverted-v signatures, with rather meager MLCAPE around 100 J/Kg, so definitely thinking that someone over the higher terrain will see a weak shower, but any activity will produce far more wind than any beneficial rainfall. Didn't increase PoPs enough to message in deterministic wording for showers in the forecast because almost everyone is expected to see no rain, with any virga showers resulting in little to no precipitation thanks to near 40F spreads at the surface.

Now...for the heat. At the time of this discussion, stations along the I-80 corridor in SE Wyoming are rapidly warming up, with Cheyenne already up to 80F before noon. Thanks to the lack of clouds and the very dry air mass with surface dewpoints currently in the 20s to low 30s, we should easily tie if not break the record at KCYS, which stands at 83F set back in 2020. Laramie also has a decent shot at breaking their record of 77F set back in 1975 thanks to 700 mb temperatures ranging from the 90-95th percentile relative to climatology over SE WY. Our Nebraska locations will likely fall just short of record criteria as slightly richer low-level moisture is present at this time, resulting in overall slower surface heating. While high-resolution ensemble guidance has median minimum RH values ranging from 15-20%, red flag conditions are not anticipated at this time due to overall winds of 5-15 mph and gusts remaining below 25 mph.

Overnight will continue to be mild (although not as mild as last night, with forecast lows expected to remain in the upper 40s to low 50s east of the I-25 corridor, and locations dipping down into the low to mid 40s further west. For some context, the climatological overnight low at Laramie tomorrow is 31F, with Cheyenne typically experiencing temperatures in the mid to upper 30s. A weak surface front looks to push across SE Wyoming and W Nebraska sometime tomorrow morning, which will result in a *slightly* cooler day tomorrow (though still 10-15 degrees above average).

Behind the back door front, a weak inverted ridge will shift the surface flow to more SSE throughout the day, helping usher in some slightly richer moisture (dewpoints in the mid to upper 30s) east of the Laramie Range. In the "cooler" post-frontal air mass, expect high temperatures to remain in the upper 70s to low 80s. So while slightly cooler than these past couple of days, it still won't feel anything like October outside. Minimum RH values are expected to range from 15-25%, however fire concerns are low thanks to weak SE winds of 5-10 knots. With slightly higher low-level moisture behind the front, cannot rule out an additional round of isolated, high- based, gusty showers later in the afternoon, confined primarily to the higher terrain. Expect another mild night on Wednesday into Thursday as we remain under the longwave ridge pattern, with 500 mb heights anomalies of +2-3 sigma relative to climatology based off NAEFS guidance.

LONG TERM /THURSDAY THROUGH MONDAY/

Issued at 1205 PM MDT Tue Oct 6 2026

The long term forecast will change from having warm light winds and clearer skies to a more active pattern. Starting sometime Friday night and through the weekend a low pressure system will start to push in from the Pacific Northwest and begin to start feeding that Pacific Moisture into the Intermountain West region. THe height gradient will also begin to tighten so breezier conditions can also be expected as the process begins to take shape. Depending on which global model you look at they all paint almost the same overall picture with some minute timing differences. However with weather, the details and timing are always the deciding factors with how this unfolds. Right now, some of the global ensembles have precipitation starting as early as Sunday morning some have it starting as early as Sunday night. Which could mean the difference of rain or snow for our mountain peaks and an earlier snowpack the better in my opinion. However, everywhere else in our area thats not the peaks of the Snowy range or Sierra Madres look to be getting rain and high temperatures look to only drop into the 50's and 60's during this period.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 1205 PM MDT Tue Oct 6 2026

It looks to be light winds and relatively clear skies for terminals through the TAF period. The afternoon wind gusts look really spotty across our forecast area but even then Winds above 20 knots aren't really expected. Overnight winds look to go light and variable with the winds predominately being easterly from 00z to 06z in the Panhandle. Some high based clouds are expected to move across the southern terminals but they are expected to be above 18,000ft for the most part so no impacts to general aviation are expected.

CYS WATCHES/WARNINGS/ADVISORIES

WY...None. NE...None.