textproduct: Cheyenne

KEY MESSAGES

- Mostly dry conditions and above average temperatures are expected to continue for much of the week ahead.

- The next chance for precipitation and temperatures closer to seasonal averages will be Friday into next weekend.

SHORT TERM /THROUGH TUESDAY/

Issued at 142 PM MDT Sun Oct 18 2026

Based off current observations, it appears the weak surface cold front has traversed most of the CWA with winds shifting more northerly. As a result, temperatures are cooler today than yesterday, but still above average for mid to late October. Cloud cover is also increasing across the area as a shortwave in southern California advects mid-level moisture into Utah and western Colorado. Clouds will also help moderate temperatures, with highs expected in the 60s for most cities in southeast Wyoming and western Nebraska. It is worth mentioning that Hi-Res guidance does show a slight chance of precipitation later this evening, mainly in Carbon County. However, it is likely too dry to get any showers/meaningful precipitation to develop.

Rinse and repeat for Monday and Tuesday as the pattern stays relatively stagnant over the next few days. Temperatures on Monday will be similar to Sunday with most locations seeing highs in the 60s as the CWA still sits behind the surface front. This front will recede back northward by Tuesday morning, leading to warmer temperatures on Tuesday. Highs east of the Laramie Range will bounce back into the 70s, which will be about 10 degrees above average for late October. Still looking at a bit of cloud cover on both days, mainly over the high terrain and areas further west. The slow moving shortwave over southern California will gradually makes its way northeastward into southern Wyoming by Tuesday. However, by Tuesday, the system will be pretty moisture starved with only a bit of mid-level moisture remaining. As a result of the shortwave inching closer to Wyoming, cannot rule out slight chances of showers both Monday afternoon/evening and during the day Tuesday. There will be a bit more lift involved on Tuesday, so Tuesday will be the day with the "greatest" precipitation chance.

LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/

Issued at 142 PM MDT Sun Oct 18 2026

The long term period starts out mild and quiet as we remain on the western periphery of a longwave ridge, placing us in a southwesterly flow regime. As a result, high temperatures on both Wednesday and Thursday will peak 10-15 degrees above climatology (average high for Cheyenne on Thursday is 57F). The southwesterly flow will allow for a surge of mid to upper-level moisture from Baja California ahead of an amplified closed low located off the coast of California. Latest NAEFS guidance suggests PWAT near the climatological maximum on Thursday (~0.75"), which is quite remarkable given that our southwestern monsoon pattern typically ends in early to mid September. The main question will be if we can actually translate any of this rich moisture down to the surface as precipitation, which has been difficult to do so far this year. Unfortunately, our prospects aren't exactly looking favorable for any widespread QPF as the main synoptic-scale forcing for ascent is temporally offset from the primary moisture plume. The main DCVA combined with weak isentropic ascent looks to be over SE Wyoming sometime on Friday, which also looks like the day with our best chance for showers. Thunderstorm chances look to be low at this time as LREF guidance and forecast soundings show MLCAPE generally below 100 J/Kg, with slightly higher values in the Panhandle. Friday also looks to be quite mild, with median high temperatures per LREF guidance staying in the mid 60s to mid 70s east of the I-25 corridor, and primarily 50s west of the Laramie Range.

The unsettled pattern will continue into the weekend as the closed low gradually translates to the east over the Desert Southwest, placing us in a region of weak zonal flow aloft. Again, not overly enthusiastic about chances for widespread precipitation across SE Wyoming and the Nebraska Panhandle given that forcing for ascent is rather weak. Still quite a ways out so not going to get into specifics, but deterministic runs are showing a cold front moving across our region some time on Saturday with a 10-15 degree drop in high temperatures relative to Thursday and Friday, so we may actually see an "average" day of fall weather this weekend with chances for precipitation, though shower coverage will likely be spotty.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 1126 AM MDT Sun Oct 18 2026

VFR will prevail through the TAF period under dry conditions. Expect light and variable winds under 10 knots for all terminals, with the exception of KRWL which may experience peak gusts up to 25 knots before 00Z.

CYS WATCHES/WARNINGS/ADVISORIES

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