textproduct: Western and Central Wyoming

KEY MESSAGES

- A weather system brings snow to western Wyoming today, spreading east of the Divide tonight and Friday. Some gusty wind will accompany the snow.

- There is still some uncertainty as to exact snowfall amounts east of the Divide tonight into Friday morning.

- Mainly dry weather returns for the weekend with gradually moderating temperatures.

DISCUSSION

Issued at 132 AM MST Thu Mar 5 2026

Nights like this make me want to reach for the antacids and aspirin. With this system, the models have been about as consistent as a cell phone signal over some of the more rural portions of our area. Each run has different wrinkles and new placements of heavier areas of precipitation and tonight is not exception. We will split the discussion into West and East of the Divide for this system.

West of the Divide...As expected, snow held off until shortly before midnight, with Afton now reporting snow as of after midnight and it should be moving into Jackson shortly. For the most part, snowfall amounts in the western mountains look to be in fairly decent shape, with most areas in the advisory range. Both the HREF and NBM ensembles give a greater than 1 in 2 chance of 6 inches of snow over the most impacted areas, the Tetons, Salt and Wyoming Range and southwestern Yellowstone. Models are also fairly consistent in the timing of the heavier snow; one period late tonight with the front, and another this afternoon / evening with the following trough / upper level low passage. In the valleys, amounts have come up in the Star Valley somewhat, but with less than a 1 in 3 chance for 4 inches or more we held off on any highlights. Snow should taper off later tonight with only a few snow showers on Friday.

East of the Divide and Sweetwater County...Uncertainty increases substantially here, hence the source of my headache and indigestion. As for most of the daylight hours, temperatures will cool with the front. However, most guidance has slowed with the progression of the showers, so many areas, especially south of the Owl Creek and Bridger range, may end up largely dry through the daylight hours. The mountains will see some showers earlier though. A few spots may see a change over the snow later this afternoon, but the warm ground should melt the snow on the roads initially.

The fun starts tonight. There is one concerning thing on a couple of model runs. It is showing a weak 700 millibar circulation moving into northern Wyoming. This could lead to a bit more snow across the northern Bighorn Basin than initially thought. There are some things working against it though. One, there is little jet support, as the core of the jet is further east. In addition, usually there is an Arctic boundary and that is not the case. For now, we upped PoPs and QPF somewhat. The day shift will have to watch this in case the trend continues. We may need an Advisory if things continue to trend wetter. Ensemble guidance gives less than a 1 in 8 chance of 2 inches or more, but I don't trust it. Things could be elevation based here, with higher elevations, like Meeteetse, Cody and Powell possibly seeing more snow than a place like Greybull or Worland. The time to watch would be after 9 pm tonight through Friday morning. The area of greatest concern would be Cody to Meeteetse, there north to northeasterly flow could bring some upslope enhancement. Another concern is Buffalo, but more for impacts. Snow tonight may combine with wind gusting possibly to 40 mph to bring difficult travel conditions for a time. Ensemble guidance only gives a 1 in 10 chance of 2 inches or more, so no highlights yet. But again, this has to be watched.

Elsewhere, the trend has been later and downward. Most guidance pushes the start of the snow later, maybe not until closer to midnight for central Wyoming. Amounts have also come down by about 20 percent. However, there continue to be differences in placement of heavier areas of snow. As a result, the most impactful time the snow looks to be between midnight and noon on Friday. We have left the advisories alone for now, but right now I would favor the lesser amounts. The generally pattern of northerly upslope is there, with the highest amounts from Lander to Casper. This area still has a decent area with at least a 1 in 2 chance of 3 inches or more according to the ensemble guidance. I initially thought of possibly canceling a couple of zones, but given the flip flopping models, we left everything alone. It is the same story for Sweetwater County. Amounts still look to be in the advisory range, especially east of Rock Springs with at least a 1 in 2 chance of 3 inches of new snow. The time of maximum impact here would be during the day on Friday. In all areas, snow should taper off by Friday evening and end shortly after midnight Friday night.

Quiet weather then returns for the weekend as ridging builds over Wyoming. Things look dry except for a few showers in the western mountains. Saturday looks like a cool day, followed by warming on Sunday as flow turns west to southwest and the snow continues to melt. The next potential weather maker will be a front moving in from the north, more than likely Monday night or Tuesday. Models are split on whether it will make it or not. As for temperatures, above normal is once again likely for much of the week, except for maybe northern Wyoming depending on how far south the front can get.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

Issued at 405 AM MST Thu Mar 5 2026

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

Marginal VFR ceilings over KJAC to start the forecast, as light snow begins to wane. Mountain obscurations will be in place and last through the TAF period. The next round of snow at KJAC is expected by 19Z, resulting in MVFR conditions. IFR conditions will occur with the heaviest bands of snow this afternoon and evening. MVFR conditions will linger after 05Z, as snow exits to the southeast.

KBPI/KPNA are expected to stay VFR, with VCSH possible between 00Z and 03Z. There is a 30% chance for snow showers at KRKS between 16Z and 19Z. West winds, with gusts up to 30kt will be in place through 02Z.

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

VFR conditions will be in place for most terminals through the first half of the forecast. KCOD will be first impacted with a 30% chance for a rain/snow mix between 22Z and 01Z. A cold front will quickly drop southward, reaching KRIW and KCPR between 01Z and 04Z. MVFR conditions will rapidly develop behind the front, with areas of snow occurring after 06Z. KLND is expected to be impacted the most with the heaviest snow, which is only a few inches.

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 5 PM MST this afternoon for WYZ001-012-024.

Winter Weather Advisory until 11 PM MST this evening for WYZ002.

Winter Weather Advisory from noon today to 11 AM MST Friday for WYZ007>009.

Winter Weather Advisory from 5 PM this afternoon to 5 PM MST Friday for WYZ014-015.

Winter Weather Advisory from 8 PM this evening to 2 PM MST Friday for WYZ018-020.

Winter Weather Advisory from 8 PM this evening to 5 PM MST Friday for WYZ019-022.

Winter Weather Advisory from 11 PM this evening to 5 PM MST Friday for WYZ028>030.