textproduct: Western and Central Wyoming

KEY MESSAGES

- Period of snow and gusty wind will bring slick roads to the Bighorns and Johnson County this morning.

- Above normal temperatures continue for most locations into next week.

- The next weather system moves in Tuesday or Wednesday with the next chance of snow and wind.

DISCUSSION

Issued at 1117 PM MST Thu Dec 11 2025

The main concern in the short term will be the expected snow and travel impacts across northern Wyoming, especially from the Big Horn Range and eastward where the Winter Weather Advisory is in effect. Snow is now spreading into the area and will continue through the night before tapering off later in the morning. As was noted by the day shift, the main concern will not be snowfall amounts, as the should remain below advisory criteria. The main concern is icy roads from the rapidly falling temperatures following the warm temperatures today, (it was in the 50s and 60s) and a possibly flash freeze. We will continue the advisory as is for now. The only other location with greater than a 1 in 3 chance of 3 inches or more is the northern Absarokas, and there are few impacts in that location. Otherwise, the challenge will be temperatures and how far south the front can reach. Johnson County and the northern Bighorn Basin will be much cooler, with the high in Buffalo possibly 40 degrees cooler than yesterday, It will remain milder further south though as the front would likely not make it. It should be a bit cooler than yesterday, but still well above normal for mid December. We will continue to have some gusty breezes at times as well with the jet close to the area, but nothing like the wind we have seen the past few days.

Zonal to flat ridging then controls the weather through the weekend and into Monday. This means a continuation of above normal temperatures and breezy conditions. It is possible we could see more high temperatures records fall, especially on Sunday and Monday following the brief cooldown on Friday and Saturday. There will be a gusty wind continuing in the favored areas, but high wind is not expected through that time period. The only fly in the ointment through this period will be one last piece of energy that could bring some snow showers to Johnson County on Saturday but any amounts would be light and impacts minimal to none.

The next likely weather maker in form of a Pacific trough and cold front then approaches for Tuesday and Wednesday. Given the zonal flow across the area, impacts look similar to this weeks situation with most of the precipitation across western Wyoming with the orographic enhancement. Models are split on if any precipitation makes it East of the Divide though. There is higher confidence in strong to potentially high wind, with most guidance having an 140 to 160 knot jet over Wyoming from later Tuesday through Thursday. Details are obviously impossible to nail down this far out though. We are highly confident on above normal temperatures continuing across most of the area through most of the next seven days.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 930 PM MST Thu Dec 11 2025

VFR conditions expected throughout the entirety of the period at all TAF sites. Light winds 10kts or less through Friday morning remaining through much of the afternoon except for CPR/RKS gusting up to 25-30kts after 18-20Z. Low chance (10-20%) of light snow showers around COD the first couple of hours of the period but confidence low carrying only VCSH at this point in time. Otherwise, another shot of north of west winds to increase after sunset around 00-01Z for COD/RIW as well as remaining elevated at RKS gusting up to 18kts expected at these locations. This should subside into the next TAF cycle with dry conditions going forward through the weekend.

Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on icing and turbulence forecasts.

RIW WATCHES/WARNINGS/ADVISORIES

Winter Weather Advisory until 7 AM MST Friday for WYZ008>010.