textproduct: Cheyenne

KEY MESSAGES

- The long duration high wind event will continue Thursday with winds slowly diminishing Thursday night. More high winds possible for the wind prones Friday into Saturday morning.

- Arctic cold front will brush eastern Wyoming and the northern Nebraska Panhandle late Friday and Friday night. Much colder temperatures and some light snow possible as far west as the Interstate 25 corridor into Saturday morning.

SHORT TERM /THROUGH SATURDAY/

Issued at 145 PM MST Thu Dec 11 2025

High winds continue in the short term, with all zones currently in a High Wind Warning already verifying. Winds remain strongest in the usual southeast Wyoming wind prones with gusts of almost 80 MPH being observed. Wind prone adjacent areas have also seen their fair share of gusts over 65 MPH. High winds will continue through the afternoon, but will start to weaken early this evening as a cold front pushes across the area. The front will turn winds more northerly, effectively shutting off high winds. Most High Wind Warnings end at 5 PM this evening with the exception of Arlington and the South Laramie Range. MSLP gradients will still remain elevated in these areas with 50 kts winds aloft and some subsidence. High winds will likely not be frequent in these areas overnight nor will we see the magnitude of gusts observed over the last several days. Behind the front, precipitation will likely move into some of the northern zones of the CWA. The coldest, or arctic air of the front will likely be along a line extending from Bill in Converse County southeast to Alliance in Box Butte County. Along this line and north is also the area that is expected to see some precipitation from this front overnight. Snow accumulations look to be light given that the airmass is quite cold and the CWA will be at the edge of the moisture plume.

Some lingering snow showers could be possible throughout the day in the aforementioned area as the arctic air boundary remains stationary. Models are in pretty good agreement with holding the boundary on that Bill to Alliance line, however, would not be surprised to see that boundary sag a little bit further south into the North Platte River Valley, bringing the colder temperatures with it. Highs on Friday north of this boundary will be quite cold with ample cloud cover. Highs in the 20s and 30s can be expected. The rest of the CWA will see cooler temperatures but not nearly as cold as the northeast corner of the forecast area. High temperatures in southeast Wyoming will still be about 10 to 15 degrees above average, thanks to some continued blustery conditions. Highs in the 40s and 50s can be expected. The southern Nebraska panhandle will see temperatures closer to average with highs in the 40s. High Wind Warnings for Arlington and the South Laramie Range expire at 5 AM on Friday, however, the potential is there for high winds to continue through the day Friday and even into Saturday morning. Parameters for high winds do definitely weaken during the day Friday, but winds in the wind prones will still be borderline. Variables like height gradients, 700 mb winds and subsidence remain elevated enough that marginal high winds cannot be ruled out in Arlington and the South Laramie Range. It may be worth extending the current Warning for these zones through Saturday morning, but an argument can be made for issuing another round of High Wind Warnings starting Friday night.

Friday night, a weak upper-level disturbance will move across the CWA, strengthening MSLP gradients and increasing winds aloft up to almost 60 kts. High wind chances look better for both Arlington and the South Laramie Range with in-house guidance suggesting 60 to 80 percent probabilities of high winds occurring. Hi-Res guidance also suggests wind gusts over 60 MPH during this time in the usual wind prones. Additional High Wind Warnings could be needed for Bordeaux, though some models show the winds too northwesterly to take advantage of the gap area. Will also have to keep an eye on the South Laramie Range foothills and central Laramie County for potential High Wind Warnings Friday night through Saturday morning. Decided to hold off an issuing anything quite yet as parameters still look quite marginal with in-house guidance for these zones showing low probabilities for high winds.

Saturday, another push of cold air will turn winds more northerly, finally shutting off the prolonged wind machine. Even the southeast Wyoming wind prones will finally see the end to the barrage of tropical storm to hurricane force winds. The stagnant jet streak that was over the CWA will finally push off to the east, leaving behind some colder, but calmer conditions. High temperatures on Saturday will be nearly identical to Friday, albeit a few degrees cooler.

LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/

Issued at 145 PM MST Thu Dec 11 2025

Ensemble clusters show strong synoptic agreement through the weekend into Monday afternoon when scenarios diverge and become more dependent upon the evolution of an incoming Pacific Northwest trough and how much the western ridge dissipates as an upper low cuts across Mexican/US border early in the week. Overall a deamplifying ridge through the weekend with retreating high pressure will lead to temporarily cooler temps Friday and Saturday but as faster zonal flow develops atop the crest of the ridge by Sunday warming temps and a high plains downslope airmass will take hold pushing daily highs into the 50s and even low 60s east of I25 through Wednesday. By Wednesday evening that previously mentioned Pacific Northwest trough should be moving across the high plains states of Montana and the Dakotas with an attendant cold front progged to push south, bringing temps back closer to seasonal averages along the front range for the later portion of the week. By the end of the week most clusters maintain some degree of zonal flow aloft with the ridge axis centered overhead but some push the ridge axis slightly further east into the plains with SW flow aloft harboring better potential for high elevation snows Wednesday and beyond.

Coincident with the expected mid to late week front will be increasing height gradients across southeast Wyoming that could end our brief (and enjoyable) break from the high winds. Currently looking to be more of a threat for the typically wind prone areas on Wednesday/Thursday but we will continue to monitor other less prone areas for any needed headlines when appropriate.

AVIATION /18Z TAFS THROUGH 18Z FRIDAY/

Issued at 1029 AM MST Thu Dec 11 2025

VFR conditions will prevail the southeast Wyoming terminals, and for the next 12 hours for the western Nebraska terminals. As the arctic front slides south across KCDR, KAIA, and KBFF late this evening after 03z Friday, MVFR CIGS and light snow/rain will develop. Further west, primary forecast concern will be strong winds and periods of LLWS. Gusts of 45 to 55 knots are expected at KRWL, KLAR, and KCYS. Winds aren't expecting to diminish much until late this afternoon and this evening.

CYS WATCHES/WARNINGS/ADVISORIES

WY...High Wind Warning until 5 PM MST this afternoon for WYZ101-104- 107-109-113-115-118-119. High Wind Watch until 5 PM MST this afternoon for WYZ105. High Wind Warning until midnight MST tonight for WYZ106-117. High Wind Warning until 5 AM MST Friday for WYZ110-116. NE...None.