textproduct: Cheyenne

KEY MESSAGES

- Hot temperatures will return to the area today and continue into early next week, producing near record highs Saturday through Monday.

- Widely scattered high-based showers and thunderstorms will be possible over the weekend. The primary hazard will be gusty winds.

- Another surge of monsoon moisture will arrive Monday, increasing rainfall chances for the early part of the work week.

SHORT TERM /THROUGH SATURDAY NIGHT/

Issued at 1246 PM MDT Fri Jul 24 2026

Drier air has moved in from the west over southeast Wyoming and western Nebraska in the wake of the prior day's monsoonal moisture surge. While the southwestern ridge remains in place just to the south of the Four Corners region, lower PWAT values have moved in over southern Wyoming along the northern periphery of this ridge axis. As a result of dramatically less moisture in forecast soundings, much lower shower and thunderstorm chances exist for today. In fact, only a few very isolated showers are in the forecast for the Snowy Range and south Laramie range, generally between the 0z to 5z timeframe. Convective-Allowing Model data has been rather inconsistent with these shower chances, with typically humid-biased models such as the Nam NEST suggesting even lower shower chances than the HRRR. While it is likely that not a drop of rain will reach the surface anywhere in the CWA today, we will maintain very low-end PoPs (around 15%) for Cheyenne westward through the Snowy Range given the HRRR/FV3's persistence in showing returns in these areas. The other story today will be the heat. Temperatures will run around 10 degrees warmer than yesterday given drier air and slightly higher heights. This warmth will only be a preview of the days to come.

On Saturday, height rises and light downslope westerly flow on the northern periphery of the monsoon ridge will result in temperatures warming by another 5 degrees or so. Very high confidence in this hot and generally dry weather pattern exists for Saturday and the remainder of the weekend, with ensemble temperature forecasts tightly clustered just shy of record values. A Heat Advisory remains in effect for most areas east of the Laramie Range from Saturday afternoon through Monday. Convective chances on Saturday will run a bit higher than Friday, but not by much. PWAT values only look to inch upward by a few hundredths, and most CAM guidance supports only widely scattered showers and perhaps some thunder. Still, given the plethora of summertime weekend activities ongoing across southeast Wyoming and western Nebraska, it will be good to stay weather aware. Forecast soundings do show some elevated and extremely high-based instability which could result in a few lightning strikes. Despite recent rains, dry fuels combined with lightning and limited precipitation will be a concern on Saturday.

LONG TERM /SUNDAY THROUGH THURSDAY/

Issued at 1246 PM MDT Fri Jul 24 2026

Sunday...Current Heat Advisory looks on track. Primary challenge will be the heat, under the dominant ridge aloft, with record high temperatures likely at Laramie, Cheyenne, Chadron, Alliance, Scottsbluff and Sidney, as 700 mb temperatures from 20 to 23 Celsius yield maximum temperatures in the lower 90s west of I-25, with 97 to 106 degrees east of I-25.

Record high temperatures for July 26th include the following current records...

100 degrees in 2025 at Alliance...105 degrees in 2021 at Chadron... 104 degrees in 1935 at Scottsbluff...99 degrees in 2011 at Sidney... 89 degrees in 2016 at Laramie...and 95 degrees in 1910 at Cheyenne.

Monday...Strong ridging aloft continues with near record high temperatures at Cheyenne, Chadron, Alliance and Sidney using 700 mb temperatures from 19 to 22 Celsius. Thus current Heat Advisory looks on track.

Record high temperatures for July 27th include the following current records...

104 degrees in 1931 at Alliance...106 degrees in 1931 at Chadron... 102 degrees in 1975 at Scottsbluff...101 degrees in 2012 at Sidney and 94 degrees in 1960 at Cheyenne.

Tuesday...Cooler temperatures expected as low and mid level moisture increases along with cloud cover. Monsoonal type moisture and diurnal and differential orographic heating will produce scattered to numerous showers and scattered thunderstorms, most numerous across and near the Snowy, Sierra Madre and Laramie Ranges.

Wednesday...A passing shortwave trough aloft will combine with plenty of low and mid level atmospheric moisture to produce scattered afternoon and evening showers and beneficial rains, primarily over and near the mountains.

Thursday...Ridging aloft reasserts itself over Wyoming and Colorado, with drying in the atmosphere noted on the models, thus will see a decrease in late day shower and thunderstorm coverage, with areal coverage highest over and near the mountains.

Friday...The flow aloft turns northerly, with the bulk of the monsoonal moisture moving into western Nebraska, and drier air infiltrating southeast Wyoming, thus it seems likely that showers and thunderstorms will eventually be confined to western Nebraska, with lesser chances over southeast Wyoming.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1246 PM MDT Fri Jul 24 2026

VFR conditions will dominate at all terminal locations this afternoon. Expect some cloud cover to increase at LAR, RWL and CYS later this afternoon into the early evening hours as mountain convection drifts east. Isolated showers are possible at RWL after 0z. Any ceiling or visibility decreases should remain well above MVFR thresholds at all terminals.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Heat Advisory from 11 AM Saturday to 9 PM MDT Monday for WYZ101-102-107-108-118-119. NE...Heat Advisory from 11 AM Saturday to 9 PM MDT Monday for NEZ002-003-019>021-054-055-095-096.