textproduct: Cheyenne

KEY MESSAGES

- A warming trend will carry through Memorial Day weekend, with near record high temperatures possible by Monday.

- Isolated high-based showers and storms will be possible each afternoon over the long weekend, but rainfall will be limited.

- Potential for thunderstorms and rainfall will increase Tuesday and continue through much of next week.

SHORT TERM /THROUGH SUNDAY NIGHT/

Issued at 121 AM MDT Sat May 23 2026

Relatively quieter weather is expected this weekend as the upper-level trough moves off to the northeast and northwesterly flow aloft returns to the region. Saturday will feature stout northwesterly flow aloft with only a few 500mb vorticity lobes moving through and out of the region. Usually, northwesterly flow aloft keeps the door open for precipitation chances across the region, but 700mb flow remains westerly with modest downward omega values, leading to dry downsloping winds drying out the surface throughout the day. A very subtle, 700mb short-wave looks to push through overnight tonight, but looks to only bring a chance for breezy surface winds as 700mb height gradients strengthen marginally overnight. However, breezy surface flow is expected throughout the afternoon along and west of the Laramie Range as surface pressure gradients remains elevated throughout the day and westerly, 700mb flow promotes sinking downslope winds along and just east of the Laramie Range. With dry conditions from downsloping winds, little to no precipitation is anticipated today, with clouds increasing ahead of the 700mb short- wave. Northwesterly flow aloft will keep temperatures on the cooler side, as compared to Sunday and Monday, with afternoon high temperatures in the mid-60s to mid-70s everywhere. Therefore, a pleasant day is in store for the start of the weekend.

Zonal flow returns for the morning and afternoon hours on Sunday, leading to continued dry conditions. A few 500mb vorticity lobes will traverse across the region during the afternoon hours, giving portions of the CWA slight chance to chance PoPs (15 to 30%) in the afternoon hours. 700mb flow will remain largely zonal Sunday morning through the afternoon and evening hours. With weak downslope flow along and east of the Laramie Range, drier conditions will continue. Temperatures will warm into the low-70s to mid-80s across the area as 700mb temperatures warm into the 8 to 11C range in the afternoon. The dry conditions will not continue long as the next upper-level system pushes into southern California Sunday evening into the early morning hours Monday. This system will turn upper-level winds southwesterly, with a decent fetch of moisture advecting in from the Pacific Ocean. Multiple lobes of stronger 500mb vorticity will eject out ahead of the incoming system, leading to the isolated to scattered precipitation chances, namely west of the Laramie Range due to drier conditions east of the Laramie Range, though an isolated shower cannot be ruled out across western Nebraska. Forecast soundings from the RAP suggests stout Inverted-V profiles across the entire CWA, leading to the threat for gusty showers Sunday evening. Minimal precipitation is anticipated to hit the ground on Sunday evening due to the dry low-levels evaporating the precipitation first. With DCAPE values over 1000 J/kg, there is further support for mainly gusty showers, but an isolated thunderstorm is possible.

LONG TERM /MONDAY THROUGH FRIDAY/

Issued at 121 AM MDT Sat May 23 2026

No major changes to the medium to long range forecast period. Please see previous long range discussion...

By Monday the synoptic pattern starts to shift as the global models have come to agreement (sort of). Previous model runs treated the synoptic setup as one low pressure system pushing into the Baja California region with another northern system to pushes into the Pacific Northwest. Now the global models all show this as more of a deep reinforced trough from the Low pushing into the Pacific Northwest. This will still push us into a southwest advecting in some moisture from the Pacific and some dry air from the downsloping winds off the mountains near the surface Monday into Tuesday. By Tuesday afternoon the low pressure system gets close enough to send a shortwave as a catalyst to another wet pattern. Thanks to our summer sun, the synoptic set up of this deep trough will lead to decent destabilization of the atmosphere and produce scattered thunderstorms for the afternoon and evening. This bowling ball of a low looks to roughly get temporarily cut off from the synoptic as a quasi-omega block begins to setup over the CONUS region. An area of high pressure appears to sit over the Northern Plains region while Lows sit and spin over the Nova Scotia region and the West coast. While the low from the West coast parks itself over Nevada it will send with corresponding shortwaves through the intermountain west for almost daily chances for precipitation through out the week and possibly the rest of this month to finish out our wet month of May.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 1031 PM MDT Fri May 22 2026

VFR remain in place for the TAF period. 5-10 knot SW flow will persist until 18Z before winds veer to westerly. Gusts of 25-30 knots are anticipated at KRWL and KLAR after 20Z, whereas the remaining terminals can expect gusts up to 20 knots. At this time, mentioned the possibility for a few high-based showers which may briefly lower CIGS, however these will produce more wind than rain thanks to a dry sub-cloud layer and weak mid-level instability. Can expect gusts up to 40 knots in the vicinity of these showers and variable wind directions, however there is a low probability (20% chance) that any terminals will see any direct impacts.

CYS WATCHES/WARNINGS/ADVISORIES

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