textproduct: Cheyenne

KEY MESSAGES

- A High Wind Warning has been issued for the wind prone areas of southeast Wyoming beginning Monday evening and continuing through noon Tuesday.

- A Winter Weather Advisory has been issued for the Sierra-Madre and Snowy ranges for Tuesday morning through Wednesday morning. - Long term remains active with multiple systems promoting prolonged periods of high winds, light snow and cold temperatures.

SHORT TERM /THROUGH WEDNESDAY NIGHT/

Issued at 259 AM MST Tue Dec 2 2025

Active weather is expected over the next 36 hours as an arctic front brings much colder temperatures, light snow accumulations and high winds to portions of the CWA. Ahead of the front, high winds will continue into the early afternoon as MSLP gradients remain steep. The GFS currently has 700 mb winds at about 50 to 55 kts with strong subsidence. This is enough to get high winds blowing at Arlington and the South Laramie Range early this morning. In-house guidance as well as the GFS have winds peaking before sunrise this morning. High winds will likely continue through the morning hours before easing this afternoon as the cold front begins to push into the CWA. Lift from the approaching front and increasing mid-level moisture will likely lead to some scattered light snow showers throughout the day. Accumulation with this first round of showers is unlikely, except in the high terrain, where Winter Weather Advisories go into effect this morning and continue through Wednesday morning.

The arctic front will begin to push into the CWA from the north later Tuesday evening. Along and behind the front, more widespread precipitation is expected. Most precipitation will fall overnight, leading to snowfall accumulations for portions of the forecast area. Most models and ensembles are in very good agreement regarding snowfall totals, giving confidence in the forecast. Outside of the mountains, the highest totals will likely be along the Interstate 80 corridor between Cheyenne and Rawlins. Winds will be northerly behind the front, leading to upslope flow and orographic enhancement of snowfall totals for the Laramie Valley, central Carbon County, and the Arlington area. About 1 to 2 inches of snow will be possible in these areas. Outside of these zones, most other locations can expect anywhere from a dusting to an inch of accumulation.

Light snow will likely continue through Wednesday morning before tapering off. Accumulations will still be possible Wednesday morning with the aforementioned locations still expected to be in upslope flow. Snow will taper off early in the afternoon, but cold temperatures from the arctic front will remain. High temperatures will only be in the 20s, with wind chills expected to be in the teens most of the day. Even colder temperatures and wind chills are expected overnight. Overnight lows will be in the teens and single digits, with wind chills below zero for most locations before sunrise on Thursday.

LONG TERM /THURSDAY THROUGH MONDAY/

Issued at 308 PM MST Mon Dec 1 2025

Mean northwest flow aloft looks to persist through the period with hints of shortwave ridging intermittently putting a damper on what seems to be near daily snow chances across the Snowy and Sierra Madre ranges. Current ensembles and clusters paint this picture well with a shortwave ridge both on Thursday and Monday passing within the vicinity of the forecast area though slight variations exist in the amplitude and track that could impact the nightly radiational cooling potential (Thursday AM lows in the single digits to teens). After a chilly Thursday morning highs climb back near freezing in the afternoon.

High winds look to return Friday after a quiet few days wind-wise Wednesday/Thursday with the in house guidance showing a greater than 60 percent chance for high wind criteria in the typically wind prone areas. This is expected to be a long duration event with the 700mb jet between 45-55kts per clusters and a tightening pressure gradient working to get these winds to the surface. At the same time things look to turn wintry once again by Friday afternoon in the mountains with several inches likely in the Snowy and Sierra Madres through Sunday as more shortwave activity brings moist flow to the higher elevations. However once again shadowing effects are likely going to limit how much accumulation we can produce outside of the high terrain. Near average temperatures continue into the weekend as we feel the impact of ridging (and the embedded shortwave activity on its eastern periphery producing the snow) keeping highs in the 30s and 40s through the weekend.

AVIATION /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 442 AM MST Tue Dec 2 2025

Active weather is expected throughout the day and into the overnight hours. During the day, strong winds are expected at southeast Wyoming terminals with gusts over 30 kts likely. A stray snow shower will also be possible throughout the day which could reduce visibility below VFR criteria. A cold front will move through overnight, switching winds out of the north and ushering in more widespread precipitation. Low CIGs are expected, as well as visibility reductions due to snow. IFR conditions can be expected at most terminals overnight.

CYS WATCHES/WARNINGS/ADVISORIES

WY...High Wind Warning until 5 PM MST this afternoon for WYZ106-116- 117. High Wind Warning until 8 PM MST this evening for WYZ110. Winter Weather Advisory until 11 AM MST Wednesday for WYZ112- 114. NE...None.