textproduct: Western and Central Wyoming

KEY MESSAGES

- A chilly but quiet Sunday across the Cowboy State with cold temperatures persisting into Monday morning.

- A warming trend begins Monday with temperatures gradually returning to slightly above normal through New Years Day.

- Little to no chances for precipitation through the first half of the week with some chances developing by the end of the week.

UPDATE

Issued at 1146 AM MST Sun Dec 28 2025

Not much to update as a quiet weather pattern looks to settle in across the region through the end of the year. Cold temperatures persist through Monday morning before a warming trend begins. Temperatures look to gradually warm through the week with highs getting back into the mid to upper 40s east of the Divide and mid to upper 30s west of the Divide by New Years Eve. Above normal temperatures look to persist into the second half of the week. Long range models continue to indicate the possibility for a disturbance bringing precipitation chances back to the state by the end of the week. However, confidence still remains low at this time with a better idea of what to expect likely to come into focus over the next few days.

DISCUSSION

Issued at 1238 AM MST Sun Dec 28 2025

It looks like old man winter has finally awakened from his long slumber and has brought Wyoming back to reality. A cold front has dropped across the area and ushered in much colder temperatures, Buffalo is down to 4 degrees as I write this, it was 61 on Christmas Day and almost 70 on Christmas Eve. As I write this after midnight, there are still some snow showers ongoing, but the overall trend is downward. All showers should be over sunrise.

All in all, we are entering a quieter period of weather as high pressure will build over the state. It looks fairly tranquil for at least the next four and possibly the next five days will be dry across almost the entire area. The main concern will be temperatures. It will be much colder today, but for most of the area, it will only be back to what is expected for late December. Northern Wyoming will be below normal, especially areas like Cody and Buffalo that saw some accumulating snow yesterday. Sunday night also looks like a rather cold night, but nothing unusual.

However, the cold won't last. Flow will turn more zonal as we go through the week and temperatures will once again begin an upward trend, surging above normal again by the end of the year. It will likely not be as warm as around Christmas, but temperatures 10 to possibly as much as 20 degrees fahrenheit above normal look very likely (at least a 4 out 5 chance) from Tuesday and especially Wednesday through the end of the week. The warm temperatures may also lead to some gusty wind in the favored locations, but high wind is not expected at this time.

The next chance of precipitation would arrive on Thursday night at the earliest, but more likely Friday or next weekend in the form of a Pacific trough. Is is far from certain though as the models have been flip-flopping for the past few days. Obviously, details are impossible to determine this far out. So, it looks like the weather as we close out 2025 and start 2026 is looking relatively quiet.

AVIATION /00Z TAFS THROUGH 00Z TUESDAY/

Issued at 335 PM MST Sun Dec 28 2025

West of the Continental Divide...KJAC/KRKS/KPNA/KBPI Terminals

VFR prevails at all terminals through 00Z/Tuesday. Mid-level warm air advection will allow for valley/basin inversions to set-up overnight. Midday Sunday high-resolution ensembles and deterministic guidance gives no hint at the development of low clouds or fog at KJAC. These inversions combined with recent snow and only high clouds overnight, there could still be a very low chance (10 percent or less) for low clouds at KJAC late tonight and Monday morning. Northerly flow aloft allows for a batch of mid/high cloud cover to transit the region late tonight and Monday. Gusty west-northwest wind Sunday afternoon diminishes at southwest terminals with the setting sun. KRKS sees west-southwest 10-20kt surface wind return around midday Monday.

East of the Continental Divide...KCPR/KCOD/KRIW/KLND/KWRL Terminals

Terminals remain VFR through 00Z/Tuesday as northerly flow continues across the forecast area. Gusty westerly wind 14-22kts Sunday afternoon at KCPR slows to around 10kts early in the period before southwest wind increases to 14-28kts between 14Z-16Z/Monday. Remaining terminals stay less than 10kts as diurnally-driven wind directions persist. Mid/high clouds increase late tonight and transit the region Monday.

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

RIW WATCHES/WARNINGS/ADVISORIES

None.