textproduct: Cheyenne

KEY MESSAGES

- A Freeze Warning remains in effect through 9AM this morning for portions of Carbon and Albany Counties.

- Warmer conditions anticipated Friday with partly to mostly cloudy skies and minimal precipitation chances.

- 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 day over the long weekend but rainfall will be limited. Rainfall potential will increase on Tuesday and Wednesday.

SHORT TERM /THROUGH SATURDAY/

Issued at 118 AM MDT Fri May 22 2026

The upper-level trough that brought severe weather to the CWA yesterday is slowly continuing its northeastward journey into northern portions of the High Plains. Zonal flow aloft will develop this morning as the short-wave trough continues northeastward. Zonal flow continues aloft through mid-morning before the next upper-level short-wave starts to push into western Wyoming, resulting in southwesterly flow aloft across southeast Wyoming and western Nebraska. Most models are in good agreement with this second short- wave being quite benign, expected to only increase cloud cover across the region throughout the afternoon and evening hours. Looking down at 500mb, vorticity advection will be neutral to anticyclonic throughout the day today, with stronger vorticity maxima not arriving into western Carbon County until 9PM this evening and ejects eastward as the upper-level short-wave pushes throughout overhead. 700mb flow shows a similar situation, with the 700mb low slowly wrapping up as it moves north-northeasterly across western South Dakota. The trailing cold front has already moves through much of the region tonight, though some isolated to scattered precipitation remains possible near Chadron due to the proximity of the strong lift associated with the surface and 700mb lows. Any precipitation activity will not linger long as it advects into South Dakota over the next 1 to 3 hours. Warm air advection at 700mb returns for this afternoon, with temperatures increasing from the -6 to -3C range in the early morning hours to the -1 to 2C range by this evening. Unfortunately, westerly flow will develop behind the departing 700mb low, leading to modest downsloping along and east of the Laramie Range. This downsloping is expected to limit precipitation chances this afternoon, while also increasing surface temperatures into the 50s and 60s once more. Strong, northwesterly flow will continue at the surface throughout the day, leading to breezy conditions across the region, but especially along and east of the Laramie Range. Westerly, 700mb flow overnight tonight will keep morning lows a bit warmer in the 30s and 40s. The best chance for another frost or freeze will primarily be in the Laramie Valley where temperatures are currently forecast to drop towards the 30 to 32F mark overnight tonight.

LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/

Issued at 118 AM MDT Fri May 22 2026

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

After this trough pushes through into the Northern Plains on Friday, a weak upper level ridge starts to build over the Intermountain West. Southeast Wyoming and the Nebraska Panhandle will largely be dry this weekend as there will be limited vorticity and decent lift to play with. However, some diurnal afternoon showers may be possible, but mostly confined to the southern half of the forecast area Saturday and Sunday. By Monday the synoptic pattern starts to shift as a progged Low pressure system starts to push into Baja California with another northern system to pushes into the Pacific Northwest. This will 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. As these two systems push into United States the southern system almost gets absorbed by the northern system to form this deep trough to kick start our wet pattern again on Tuesday most likely in the afternoon. 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. The models really start to diverge with the synoptic pattern after Wednesday morning. The GFS has a tilted ridge working its way into the Intermountain West possibly drying us out or we can go with the Euro or Canadian that have systems of varying intensities keep us rainy and stormy throughout the week. It will be interesting to see how the models trend past our Tuesday trough.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 503 AM MDT Fri May 22 2026

A low cloud deck has settled over much of western Nebraska behind the cold front and is currently impacting KBFF, KCDR, and KAIA, with KSNY just on the edge of the deck. MVFR ceilings are anticipated to continue for the next 1 to 3 hours in western Nebraska. There is the potential for KSNY to see some of these lower clouds as satellite currently shows the southern flank of clouds starting to extend towards KSNY. Included a TEMPO group for MVFR ceilings due to lower confidence in the MVFR ceilings sticking around. Partly cloudy skies will return for the late-morning hours.

Gusty winds are ongoing across much of the area and are expected to continue through much of the 12Z TAF period. Light, variable winds are currently anticipated to return between 02 and 05Z overnight tonight. There is a small chance for a lingering shower or two to impact KCDR, so a PROB30 group stands for the time with the highest likelihood of precipitation returning.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Freeze Warning until 9 AM MDT this morning for WYZ104-105- 109>111-113-115-116. NE...None.