textproduct: Western and Central Wyoming

KEY MESSAGES

- Mainly dry conditions today with wind decreasing through the day.

- Well above normal temperatures and dry conditions for Sunday and Monday.

- The next system approaches midweek next week with the next chance of snow in western Wyoming and strong to high wind across central Wyoming.

DISCUSSION

Issued at 1258 AM MST Sat Dec 13 2025

If there has been something persistent for the past couple of days, it has been the Wyoming Wind Machine. It has been working overtime for the past five days or so, and it continues tonight as well. We do have a few gusts approaching high wind, but these are mainly on bluffs where impacts are few to none. And there is some good news in the forecast in this regard. The jet stream that has been responsible for the wind will begin to retreat to the north today and 700 millibar winds get cut from 30 to 50 percent. This should allow wind to decrease through the day, with most places to see at most, breezy conditions (at least by Wyoming standards). There may be just enough lingering jet energy for some showers across northern Johnson County, but any accumulation would only be a dusting with all showers over by noon.

The other question will be temperatures. Areas south of the Owl and Bridger Creek range will have another mild day with some locations into the 50s. The wind has also mixed out over Natrona County, so temperatures should be above normal again. Johnson County remains rather cold and we have kept them in the 20s for high temperatures.

Sunday and Monday will be dominated by flat ridging that will bring a continuation of dry conditions. It will also bring a warm up, some locations rather dramatically. This could especially be the case at Buffalo, which could be 35 to even 40 degrees warmer than today as the cold air gets scoured out. And, it turns out the Wyoming Wind Machine will only be down for maintenance this afternoon and evening, as the wind increases again in the favored southwest flow areas, mainly from Muddy Gap through Casper. However, the chance of wind gusts past 40 mph is at most 1 out of 3 and this is only at wind prone locations like Wyoming Boulevard and the high bluff locations with little impact.

Things get active again for the middle of next week as the next Pacific cold front and trough approach from the west. No surprise, today's guidance has come in a bit slower today, so chances of precipitation have been lowered for Tuesday. The main impacts now look to be on Wednesday. Wind will begin to increase on Tuesday, but the main impact looks to be Wednesday. This looks similar to earlier this week with a good set up for high wind. There will be a tight pressure gradient across the area with the front approaching. The real driver of it will be a powerful jet stream, possibly over 150 knots, that will be over the area on Wednesday. The 700 millibar winds are shown as high as 75 knots. Ensemble guidance shows at least a 1 in 2 chance of wind gusts past 50 mph on Wednesday as well. It is too early for highlights, but there is a greater than 3 out of 4 chance for some High Wind Watches or Warnings to be issued for this event. This also looks to be a decent snow maker for the western mountains, with probabilistic guidance giving a greater than 9 out of 10 chance of over 6 inches of snow. Downsloping flow would keep areas east of the Divide largely dry, although some showers may occur with the passage of the front. This should bring in some cooler air, but it should still be above normal temperatures-wise given the Pacific origin of the air. Another Pacific system may then approach for another chance of rain and snow on Friday.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 410 AM MST Sat Dec 13 2025

LLWS conditions are expected to have retreated away from KCOD and KCPR and be more located over the Absaroka and Wind River Mountains through 18Z. Mountain obscurations will be over the northern end of the Bighorns through 22Z. Wind gusts around 25kt continue at KRIW and KRKS, with a 40% chance of gusts around 35kt at KRIW through 15Z. The winds at KRIW will decrease by this time, before increasing again by 18Z. Winds will be light (10kt or less) at all other terminals through the period. The winds at KRIW and KRKS will decrease by 00Z and 02Z, respectively.

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

RIW WATCHES/WARNINGS/ADVISORIES

None.