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 WEDNESDAY/

Issued at 300 AM MDT Mon Oct 19 2026

Mid-level water vapor still shows the weak shortwave slowly moving through and exiting the southern Colorado region. Models still show the cloud covers slowly clearing this afternoon and evening. So most of us should have a few clouds in the sky in the morning that disappear by the afternoon. Meanwhile 700mb temperatures still hover around 6 to 7C today so afternoon temperatures are expected to be about the low to mid 60's across the forecast area. Tuesday, we will warm up a tiny bit with temperatures possibly in the low 70's for the lower elevation along and east of the I-25 corridor. The higher elevations in Carbon and Albany county look to hangout in the 60's and mid to low 40's on the mountains around 9-10,000ft. There is a slight chance for Carbon and Albany counties to inherit light showers from Colorado Tuesday afternoon with another weak shortwave pushing through. But, right now its uncertain if those showers will be strong enough to reach the ground when they get here so I kept the probabilities below 15 percent so rain showers don't show up in our grids yet for that uncertainty. Finally, the winds look to be rather light for our region but we may get enough downsloping and warm air advection from the approaching waves to keep the overnight temperatures in the 40's. So this is essentially another pants and possibly fleece forecast brought to you by the NWS!

LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/

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 TUESDAY/

Issued at 1145 AM MDT Mon Oct 19 2026

Weak southwest flow aloft will prevail, with a weather weather disturbance approaching the terminals tonight.

High confidence in scattered to broken clouds near 15000 feet prevailing. Sufficient surface gradients will support wind gusts to 25 knots for the Wyoming terminals until early evening, with gusts to 23 knots at Rawlins after 16Z Tuesday.

CYS WATCHES/WARNINGS/ADVISORIES

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