textproduct: Cheyenne

KEY MESSAGES

- The long duration wind event continues, with wind gusts expected to peak Tuesday. While some breaks or lulls will occur, high winds will be a concern every day through Saturday.

- A cold front will bring a banded rain and snow showers late Tuesday afternoon through the evening. This will also bring a brief reprieve from the wind into Wednesday morning.

- High winds return Wednesday with another round of High Wind Watches in place for the southeast Wyoming wind prones and wind prone adjacent areas.

SHORT TERM /THROUGH THURSDAY/

Issued at 307 PM MST Tue Dec 9 2025

High Wind Warnings are performing excellent with most zones consistently verifying throughout the day. Peak gusts have occurred in the usual wind prones with frequent gusts over 80 MPH. Wind prone adjacent areas have see gusts in the 70s and the high plains have seen 50 to 60+ MPH winds. High winds will continue through the afternoon hours as steep MSLP and height gradients keep winds aloft above 55 kts. A cold front moving into the CWA this evening will effectively shut off the winds as MSLP gradients weaken and winds turn more northwesterly. This break, however, will be short-lived as the next round of high winds is progged to start Wednesday morning.

The incoming cold front will likely bring some precipitation to the CWA this evening and overnight. Based off Hi-Res guidance, precipitation looks scattered and almost convective in nature as weak pockets of instability exist. Given the instability and lingering strong winds, squall-like showers could be possible, especially overnight when precipitation is more likely to be snow. Some light snowfall could be possible for the high valleys west of the Laramie Range, but accumulations should generally stay under an inch. Winter Weather Advisories are in place for the Snowy and Sierra Madre this afternoon through Wednesday morning as the front will bring good mid-level moisture and upslope flow to the high terrain. Accumulations will be between 6 and 12 inches with the highest peaks expected to see more.

High winds will return to the area once again on Wednesday as the the 250 mb jet streak continues to linger over the region. A series of weak upper-level disturbances will traverse the CWA throughout the day, allowing a surface trough to develop in lee of the Laramie Range. This surface trough will cause MSLP and height gradients along and west of the Laramie Range to steepen, increasing winds aloft. Luckily, the parameters for this event do not look as severe or as widespread as the event currently ongoing. However, the wind prone locations can still expect to see gusts over 70 MPH and wind prone adjacent areas could see gusts over 60 MPH. Winds will gradually begin to increase throughout the morning hours, with mixing helping to get some of these winds down to the surface during the afternoon. For now, decided to leave the High Wind Watches in place for this secondary event. Upgrades to these Watches are likely, however did not want to upgrade quite yet with High Wind Warnings currently in place for the ongoing event. High Wind Watches are in place for the usual southeast Wyoming wind prones and wind prone adjacent areas. High winds are likely to continue into Wednesday night as gradients remain steep and winds aloft remain strong. Subsidence should be more than sufficient to get these winds down to the surface.

It comes as no surprise that high winds are likely to continue through the day Thursday. Gradients remain tight with roughly a 15 mb gradient expected over the CWA. This will allow winds aloft to remain in the 55 to 65 kt range with strong downward omegas. The biggest change to the forecast package came with the modification of ending times for this second high wind event. The GFS keeps the strong winds around longer than previous runs, so decided to extended the High Wind Watches through Thursday evening. Besides the never ending winds, Thursday will be quite warm thanks to a warm front that will move across the region late Wednesday night. Temperatures east of the Laramie Range will make it into the upper 50s and 60s! This will put temperatures about 20 degrees above average for mid-December!

LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/

Issued at 307 PM MST Tue Dec 9 2025

As this high wind event finally begins to tail off into the weekend the wind prones will likely still need a warning for the better part of Friday and possibly Saturday as well. With the active jet once again impinging upon the area and the ridge getting nudged back west, 50-55+ kt 700mb flow will once again become entrenched over the southeast WY plateau. Given this low level wind max and pressure/height gradients remaining favorable, high winds are likely to persist into the early weekend (midday Saturday) in the wind prone areas of I-80 and I-25 near Bordeaux. With confidence still not quite there in terms of start/end timing combined with the warning soup that is the preceding few days will hold off on any additional headlines for now to try and avoid any confusion.

Beyond what seems to be the unending high winds is a good downslope airmass which look to take hold (really starting today) and not let go well into next week as highs frequently climb into the 50s near the Colorado stateline for Friday/Saturday, and for all areas east of I-25 Sunday and beyond into the middle half of next week. Look forward to this weekend for some calmer December weather.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/

Issued at 432 PM MST Tue Dec 9 2025

Winds have dropped off for all terminals with gusts 40kts or less and continuing to drop through the evening. Nebraska terminals will see winds go light by the morning hours with W/SW winds in the afternoon Wednesday. for Wyoming sites westerly winds and gusty conditions prevail but overall much better than today. Gusts do return for RWL and LAR in the afternoon at 40-50kts but other than gusty winds no expected aviation hazards.

CYS WATCHES/WARNINGS/ADVISORIES

WY...High Wind Warning until 8 PM MST this evening for WYZ101-102- 104-105-108-109-119. High Wind Watch from Wednesday morning through Thursday afternoon for WYZ101-107. High Wind Warning until midnight MST tonight for WYZ103-106- 107-113>115-117-118. High Wind Watch from late tonight through Thursday afternoon for WYZ104-109. High Wind Watch from Wednesday morning through Thursday afternoon for WYZ105-113-115. High Wind Warning from 9 AM Wednesday to midnight MST Thursday night for WYZ106-117. High Wind Warning until 5 AM MST Friday for WYZ110-116. Winter Weather Advisory until 11 AM MST Wednesday for WYZ112- 114. High Wind Watch from Wednesday morning through Thursday evening for WYZ118. NE...High Wind Warning until 8 PM MST this evening for NEZ002-003- 019>021-054-055-095-096.