textproduct: Cheyenne

KEY MESSAGES

- Record breaking warmth is expected once again today.

- Brief high winds possible on Christmas Day with gusts up to 65 MPH. Gusty winds continue into Friday.

- Colder temperatures for Sunday and Monday.

SHORT TERM /THROUGH FRIDAY NIGHT/

Issued at 143 AM MST Thu Dec 25 2025

Mostly benign weather continues throughout the end of the week, even as upper-level flow transitions from mostly westerly to right about southwesterly throughout the day today then heads right back to due westerly early Friday morning. This leads to yet another round of gusty winds across portions of the region. Checking down to the 700mb level, a weak shortwave will increase height gradients across the CWA. While the low-level jet is not really that strong, maxing out at 55 to 60kts, the surface winds in Carbon County will increase to 25 to 30 mph, with expected surface gusts approaching 65mph. These winds will slowly weaken this morning into the afternoon hours as gradients shift to a more north/south orientation, leading to westerly 700mb winds across the Laramie Range by early this afternoon. Forecast wind strength has weakened in the most recent model runs, suggesting a more marginal wind potential for the Laramie Range and areas near the I-25 corridor. In-house random forest guidance is definitely less confident in high winds for the I-25 corridor. However, High Wind Watches will remain in effect as many people are likely to be traveling for the holidays. Despite the low probability for continuous high winds along I-25, any sudden peak in winds may result in a quick 60mph gust along the roads, yet multiple gusts above 60mph are not anticipated at this time. Heading into the afternoon today, strong winds will lead to ongoing above average temperatures as downsloping warming locally increases the surface temperatures. Highs today will increase into the 60s and 70s east of the Laramie Range while decreasing slightly from yesterday's high temperatures for many areas west of the Laramie Range. High temperatures west will yet again be in the mid-50s, though cooler than highs in the same areas yesterday.

Precipitation chances will begin to increase throughout the day today, as a shortwave trough pushes into the region. NAEFS Mean IVT will be above the 99th percentile across the mountains this evening. With southwesterly upslope flow expected, rain will start in the mountains before quickly transitioning to a rain/snow mix then fully snow during the overnight hours. 2 to 4 increase of snow is expected for the Sierra Madre and Snowy Ranges tonight through the early morning hours Friday. On Saturday, another snowfall event is expected in the mountains and looks to drop much more snow than the Thursday/Friday event as an upper-level trough begins to push into the Intermountain West. With NAEFS Mean IVT above the 90th percentile Friday night as the trough approaches and southwesterly, upslope flow continues, another 6 to 12 inches of snow will be possible for the Sierra Madre and Snowy Ranges. This system has overall better dynamics than the Thursday/Friday system and is colder overall, so snow is expected to be the primary precipitation type and have more efficient snow production than the first event. More information about the Saturday snow potential can be found below, in the Long Term forecast discussion.

LONG TERM /SATURDAY THROUGH WEDNESDAY/

Issued at 143 AM MST Thu Dec 25 2025

No major changes to the long term forecast. Please see previous discussion...

Friday morning, the upper level ridge will be shifting off to the east centered over the Northern Plains as an upper level low pushes into the Pacific Northwest. This will allow some of the colder air to push into the Intermountain West. As the ridge weakens and weak shortwave will push through Wyoming on Friday. This shortwave will give the mountain areas west of I-25 increasing precipitation chances throughout the day Friday. The precipitation looks to start as a rain/snow mix but as we start to cool off, the precipitation should transition to snow by the late afternoon to early evening lasting until Saturday morning. The winds will be slightly gusty in our wind prone areas as a weak 700mb jet develops but winds are expected to remain elevated and not reach high wind criteria. Although a rogue wind gust exceeding 58 mph can't be ruled out it's not expected to meet our High wind criteria. By Saturday morning the parent trough will be pushing through the Intermountain west. As this trough pushes through the Intermountain west there will be some moisture and colder air associated will it. NAEFS Integrated Vapor transport (IVT) depicts IVT values to reach and remain in the 90- 98th percentile from late Friday night and throughout the day Saturday. Temperatures will drop as a cold front accompanying this trough pushes through the region. The overnight temperatures look to drop into the teens as the colder air settles into the region. This will also bring colder but seasonable temperatures to the region Sunday with temperatures in the 30's. However, these winter-like temperatures will be short lived as both model and ensemble guidance look to reach a consensus about another upper level ridge setting up and pushing into the region these last few days of December.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

Issued at 402 AM MST Thu Dec 25 2025

Prevailing VFR conditions expected for most terminals through the 12Z TAF period. KRWL may see some isolated to scattered showers between 14 and 20Z, which may temporarily drop the terminals to near- MVFR conditions. Showers move out of the area by 21Z. Gusty winds are expected throughout the day, with KCYS, KLAR, and KRWL gusting between 30 and 45kts throughout the afternoon hours. Nebraska terminals will be less gusty, with wind gusts only around 25 to 30 kts. Calmer winds return late this evening.

CYS WATCHES/WARNINGS/ADVISORIES

WY...High Wind Warning until 11 AM MST this morning for WYZ104-109. High Wind Watch from 2 PM MST this afternoon through Friday afternoon for WYZ106-116-117. High Wind Warning until 2 PM MST this afternoon for WYZ110. NE...None.