textproduct: Cheyenne

KEY MESSAGES

- Warmer and drier conditions begin to return today, with warm warm temperatures expected Thursday and Friday.

- Elevated fire conditions anticipated Thursday through the end of the week.

- Warm and dry conditions continue through the weekend, though slightly cooler temperatures are expected.

SHORT TERM /THROUGH THURSDAY NIGHT/

Issued at 113 AM MDT Wed Aug 19 2026

Upper-level ridging continues to build across the western CONUS Wednesday and Thursday, leading to much drier conditions with warmer temperatures returning to the region. 500mb vorticity advection will continue throughout the day both Wednesday and Thursday, but, with the monsoonal moisture tap largely cut off, precipitation chances remain near-zero. 700mb flow will remain benign through mid-week with only a brief wind enhancement expected Wednesday afternoon across western portions of the CWA. In addition to benign 700mb flow, much warmer 700mb are on tap with temperatures topping out around 10 to 16C on Wednesday. Slightly warmer 700mb temperatures are expected Thursday when the ridge is reaching peak strength and starting to shift more directly overhead, rather than off to the west. 700mb temperatures peak around 15 to 17C for Thursday. With much warmer air aloft, surface temperatures will start to rise, especially on Thursday. Cooler temperatures continue Wednesday with highs in the 80s everywhere, with temperatures in the mid-80s to mid- 90s for Thursday. This warming trend will continue through at least Friday. Precipitation chances will be minimal to none throughout the middle of the week, due to to the much warmer and drier airmass pushing into the region. However, warmer and drier conditions with little to no precipitation will act to increase fire concerns Wednesday onwards. Afternoon minimum humidity values on Wednesday will be in the 15 to 25 percent range everywhere, though winds remain largely light outside of Carbon County. There is a potential to see a brief period of critical fire conditions in central Carbon County this afternoon, but confidence is fairly low on this persisting for 3 or more hours after a fairly moist past couple of days. Similarly, on Thursday, afternoon humidity values remain in the 15 to 25 percent range, but winds will be significantly calmer, especially across Carbon County.

LONG TERM /FRIDAY THROUGH TUESDAY/

Issued at 113 AM MDT Wed Aug 19 2026

Friday...The mid level, 500 mb, or about 18,000 feet MSL, ridge axis moves to a Grand Junction, Colorado to Great Falls, Montana axis, with its dominance continuing across our forecast area of southeast Wyoming and western Nebraska, continuing the dry conditions for our neck of the woods. Warming trend continues as 700 mb temperatures rise to near 19 Celsius, producing maximum temperatures from the upper 80s to mid 90s.

Saturday...With the upper ridge axis, near 500 mb, or 18,000 feet MSL, transitioning into the western Great Plains states from the Dakotas southward to eastern Colorado, west southwest flow aloft will develop over our counties, helping the pseudo monsoonal moisture to creep back into our forecast area from western Colorado through primarily our western counties west of I-25. Afternoon thunderstorms will be most prevalent across our Snowy, Sierra Madre and southern Laramie ranges, with evening thunderstorms, isolated to widely scattered, spreading across our entire forecast area, with of course the greatest areal coverage over our mountainous zones due to differential and orographic effects. With additional cloud cover and precipitation coverage, high temperatures will be tempered somewhat despite the warm mid level temperatures.

Sunday...More scattered beneficial showers and thunderstorms will occur in a carbon copy type day compared to Saturday, with broad northwest flow aloft over southeast Wyoming and western Nebraska, and pseudo monsoonal moisture over the counties. Carbon copy day temperature wise to Saturday, for the aforementioned reasons from Saturday.

Monday...Looks like the best chance for measurable rainfall, of 0.01 inch or more, with scattered to numerous afternoon and evening showers, and scattered thunderstorms due to increased monsoonal moisture, light steering winds and PWATs, Precipitable water increases. Slight cooling in maximum temperatures due to lowering of mid level temperatures and additional cloud and precipitation coverage.

Tuesday...Ridging aloft amplifies over the Rockies, though with monsoonal moisture trapped under the ridge from western Colorado through the western half of Wyoming, and to a lesser coverage over eastern Wyoming and western Nebraska, expect to see another carbon copy type day with scattered to numerous showers, and scattered thunderstorms during the afternoon and evening hours. Similar maximum temperatures compared to Monday, with clouds and precipitation coverage tempering highs, with readings peaking i the 80s to lower 90s.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 1134 AM MDT Wed Aug 19 2026

A dominant ridge aloft will extend over western Wyoming and western Colorado, keeping our weather dry.

For the TAFS...high confidence in VFR prevailing, with scattered high based cumulus at times until sunset. The low level jet will develop across western Nebraska late tonight, possibly producing gusty south winds at KAIA, along with some MVFR level cloud cover. Surface gradients and mix down winds will produce occasional wind gusts to 22 knots until sunset.

CYS WATCHES/WARNINGS/ADVISORIES

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