textproduct: Cheyenne

KEY MESSAGES

- A long duration wind event is beginning today. While some breaks or lulls will occur, high winds will be a concern every day through Friday.

- Damaging winds are expected near and in the lee of southeast Wyoming mountain ranges Monday evening through Tuesday evening. Gusts up to 90 mph are expected.

- Cheyenne, Laramie, Rawlins, Wheatland, and Douglas can expect wind gusts up to 75 mph tonight into Tuesday.

- Wind gusts up to 70 mph are expected to spread into High Plains during the day Tuesday.

- A backdoor cold front may bring a brief reprieve from the wind along with a chance for snow showers Tuesday night into early Wednesday before winds pick up again Wednesday.

SHORT TERM /THROUGH TUESDAY NIGHT/

Issued at 251 PM MST Mon Dec 8 2025

The short term forecast remains on track for a high end high wind event across nearly the entire forecast area. High Wind Warnings this afternoon are currently in effect for the usual southeast Wyoming wind prones of Arlington and the South Laramie Range. Frequent gusts over 60 MPH have been occurring throughout the day with gusts over 70 MPH popping up across the Arlington area. High winds will continue in these zone through at least Friday, as a stagnant upper-level pattern parks the right exit region of a 250 mb jet streak right over the CWA.

Heading into the evening hours, the jet streak will begin to move into the CWA, increasing winds aloft. As the night progresses, more zones will come online into the High Wind Warning, with nearly all zones in a Warning by 5 AM Tuesday. The biggest change in this forecast package was the upgrade of High Wind Watches in far eastern Wyoming and the Nebraska panhandle to Warnings. Confidence has grown considerably in this being a large-scale impactful high wind event. Given the parameters displayed by the GFS, this is no typical high wind event, but definitely a higher end event. MSLP gradients will be considerably steep, with nearly a 20 mb gradient across the CWA! Both 850 and 700 mb CAG to CPR height gradients are nearly maxed out with some of the highest values seen in recent memory. As a result, winds aloft over the wind prones and wind prone adjacent areas exceed 75 kts. High plains locations will even see winds aloft of 60 to 70 kts! Downward omegas are also essentially "maxed out" over the wind prones and adjacent areas as well, meaning these strong winds will more than likely make it down to the surface. On top of this, a strong mountain wave signature is evident in cross sections of potential temperature and omega fields over and in lee of the Laramie Range. Breaking mountain waves will also ensure that these winds will make it down to the surface.

The aforementioned parameters look to peak by mid-morning on Tuesday, however the strongest winds are likely expected between late morning and mid-afternoon after some mixing has taken place. As previously mentioned, this will be no ordinary high wind event. The wind prone areas of Arlington, Bordeaux and the South Laramie Range could see damaging wind gusts in excess of 90 MPH. Population centers in southeast Wyoming like Cheyenne, Laramie, Rawlins, and Wheatland could see wind gusts of 75 MPH. Remaining high plains locations including the Nebraska panhandle could see 70 MPH gusts. Winds will ease Tuesday evening across most of the CWA (excluding the usual wind prones), as a cold front pushes into the area. Winds will turn more northwesterly behind the front, essentially shutting off high winds briefly before another event is expected Wednesday. Aside from winds, the cold front could bring some light snow to the area, although accumulations are not likely outside of the mountains.

LONG TERM /WEDNESDAY THROUGH MONDAY/

Issued at 251 PM MST Mon Dec 8 2025

The big story for the first few days of the long term, after a brief lull Wednesday morning, will be the continuation of high winds. Guidance is depicting, with appropriate parameters, winds ramping up Wednesday afternoon. In the mid-levels, 700mb winds in the 55 to 66 knot range coupled with negative Omega (GFS), will help bring those stronger winds to the surface. So, for the typical wind prone areas across southeast Wyoming, gusts could top out around 80 mph along the I-25 and I-80 corridors, possibly a few stronger gusts. These stronger winds should primarily stay out of the Nebraska panhandle; however, a couple gusts near 35 mph may make it in. These stronger winds, diminishing slightly, will persist into and through Wednesday afternoon/evening. By Thursday afternoon and for the remainder of the the long term period, we are not expecting another major wind event. However, some other changes may be in store for portions of the CWA. An arctic front will dive south across the High Plains out of Canada Thursday afternoon into Friday, clipping northeast portions of our CWA. If winds diminish quicker than anticipated, the arctic front may impact more of the CWA. So, as of now, Chadron and Alliance will feel the brunt of this front with cooler temperatures seeping in along with an increased threat of precipitation. In short, highs will generally climb into the 40s and 50s while lows dip into the 20s and 30s, and down into the teens for Chadron and Alliance. The bulk of the precipitation associated with the arctic front should remain to our northeast, with Chadron and Alliance seeing the best chances of snowfall. Meager accumulations expected in this area with generally an inch or less. Any fluctuation in the track, accumulations could spike to near three inches. Beyond Thursday, a 500mb ridge will slide in and as a result, weather conditions across the CWA should become and remain relatively benign for the remainder of the long term period.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 442 PM MST Mon Dec 8 2025

VFR conditions expected over the next 24 hours. Winds will be very strong, increasing overnight into tomorrow with widespread gusts in the 50-60+ knot range with low level wind shear during the overnight into early morning hours as winds ramp up aloft and then mix down to the surface. Cloud banks at high to mid levels at SCT to BKN.

CYS WATCHES/WARNINGS/ADVISORIES

WY...High Wind Warning from midnight tonight to 8 PM MST Tuesday for WYZ101-104-105-109. High Wind Watch from Wednesday morning through Thursday morning for WYZ101-107-118. High Wind Warning from 2 AM to 8 PM MST Tuesday for WYZ102-108- 119. High Wind Warning from midnight tonight to midnight MST Tuesday night for WYZ103-107-114-118. High Wind Watch from late Tuesday night through late Wednesday night for WYZ104-109. High Wind Watch from Wednesday morning through Thursday morning for WYZ105-106-113-115-117. High Wind Warning until midnight MST Tuesday night for WYZ106- 117. High Wind Warning until 5 AM MST Friday for WYZ110-116. High Wind Warning from 8 PM this evening to midnight MST Tuesday night for WYZ113-115. NE...High Wind Warning from 5 AM to 8 PM MST Tuesday for NEZ002-003- 019>021-054-055-095-096.