textproduct: Western and Central Wyoming

KEY MESSAGES

- Elevated to critical fire weather remains likely in Natrona, southeastern Fremont and southern Johnson Counties this afternoon.

- An approaching weather system will bring moderate snow to western Wyoming and widespread strong to high wind (30 to 70 mph) Monday night through Tuesday.

- Another weather system brings widespread light to moderate snow from Wednesday through Thursday morning, including lower elevations east of the Divide.

UPDATE

Issued at 1011 AM MST Mon Feb 16 2026

Some updates to highlights concerning the weather system for tonight through Tuesday. Starting with snow, have added Winter Weather Advisories to Star and Jackson Valleys. Current thinking is that models are underdoing snow potential a little here given the showery nature of the snow and favored southwest to southerly flow. The most likely amount is 2 to 4 inches, though it should be noted there is about a 40 percent chance for Jackson town to get more than 4 inches and a nearly 60 percent chance for more than 4 inches in Alpine. The push to an advisory then comes from the addition of wind. With the falling snow, gusts 30+ mph will be occurring, resulting in winter travel conditions.

Another spot of focus for snow is Sweetwater County, up to South Pass, and possibly east towards Casper (less confidence in the eastward extent). Hi-res models are depicting higher intensity snow bands/showers moving across Sweetwater County after midnight tonight, moving eastwards through the early Tuesday morning hours. With these potential showers, localized, brief periods of heavier snow are possible across portions of I-80 and South Pass. Models weaken these showers as they head east into Natrona and Carbon Counties, so confidence is lessened in the impacts of these showers for the latter half of Tuesday morning.

The other weather element to discuss is wind. With better hi-res data coming in, the High Wind Warnings have been extended. Downsloping winds on the typical lee side of mountains have prompted most of the extensions, which now also include the Cody Foothills and Johnson County. Bottom line is that Tuesday is going to be very windy, with widespread gusts 30 to 60 mph across the area. Wind prone locations, like Outer Drive in Casper or lee side mountains, will likely see 70+ mph gusts. One area of lesser confidence is southwest Wyoming, including far western Sweetwater County (west of Rock Springs) and southern Lincoln County; for these locations gusts around 60 mph could occur between roughly 2am and 10am MST, but confidence is not high enough to include in the warning as expected winds are more in the 40 to 50 mph range. To reiterate, there will also be snow across the west, especially Tuesday morning, so winter travel conditions are expected due to the combination of snow and wind.

With the focus on tonight and Tuesday, there are not any major updates to the Wednesday/Thursday system. Much needed snow amounts east of the Divide have remain fairly similar, with a slight increase, generally putting lower elevations in the 3 to 5 inch range.

DISCUSSION

Issued at 247 AM MST Mon Feb 16 2026

It will be a rather active three days across the area, and there will be some contrasts in conditions across the area. So, we are doing something we haven't done in a while, splitting the discussion into West and East of the Divide.

West of the Divide...The main concern here will be snow. However, this will not be a huge concern today. High pressure should bring one more mild and dry day with a mix of clouds and sunshine. There will still be a few snow showers in the northern mountains, but like yesterday, any impacts would be slim to none through today and even into the evening. Models have now come into better agreement in regards to the timing of the steadiest snow, which should fall, like the day shift said, from around 2 am through around noon Tuesday. This could especially impact the morning commute, which is when the trough axis and front pass, possibly bringing 1 inch or greater snowfall rates at times. Current highlights still look good, covering the locations that have at least a 1 in 2 chance of 6 inches or more of snow through 5 pm Tuesday. With the fast movement of the system, the chances of 12 inches or more are very small, with the only locations having a greater than 1 in 3 chance being the very highest elevations of the Wind River Range and southwestern Yellowstone, where impacts are slim to none. This will also be a rather windy system, with a greater than 1 in 2 chance of wind gusts past 40 mph, even in the valleys. Snowfall amounts should remain sub-advisory in the valleys though, with less than 1 in 2 chance of 3 inches. It could get nasty for a time Tuesday morning though with the frontal passage. Snowfall rates should then decrease in the afternoon, with a lull in the snow on Tuesday night.

A second system will be on its heels for Wednesday, especially in the afternoon and at night. There is a bit more disagreement though with timing and placement of the heaviest snow with this system. At this point, the areas with a greater than 1 in 2 chance of 6 inches or more are similar to Tuesday's system, mainly the Tetons, Salt and Wyoming Range and the Wind River Range. There could be a bit more in the valleys though, given flow is more southerly than westerly, with a greater than 1 in 2 chance of 3 inches. It is too early for highlights though, especially with the first system ongoing. I do have a concern for Interstate 80 with this system as well. Some guidance is indicating a weak low developing across southern Wyoming, tightening the pressure gradient. Snow amounts do not look like much, with only a 1 in 2 chance of an inch or more. However, there is a greater than 1 in 2 chance of wind gusts over 50 mph on Wednesday evening. So, there would be a period of very difficult travel conditions.

Conditions should improve by Thursday, with only some leftover showers. A few orographic showers should continue, but no major systems are expected from Friday into the weekend. Temperatures will finally drop below normal by Thursday, but with the Pacific origin of the airmass, it will not be bitterly cold. Temperatures should then moderate toward the weekend, back toward near normal levels by the beginning of next week.

East of the Divide...Concerns are more numerous in these locations. For today, it will be another mild and dry day. We continue to have elevated to critical fire weather across much of the area. Although relative humidity still looks to remain above critical levels, given the impacts from the dry fuels, we will continue the Red Flag Warning. The real concerns start tonight and especially tomorrow though.

Wind will really begin to increase as the Pacific front approaches the area from the west and tightens up the pressure gradient, with some models showing 22 millibars from Gillette to Evanston. The 700 millibar winds increase to 60 to 65 knots late tonight and into Tuesday. Given the Red Flag Warning, we have elected to let the upgrade occur near or after it's expiration. The strongest wind isn't expected until during the day on Tuesday. Given recent model trends of both the deterministic and probabilistic variety, we have also hoisted High Wind Watches for Fremont County. The NBM ensemble shows at least a 2 out of 3 chance of maximum wind gusts of 60 mph or more here. This tends to be a bit overzealous, but it is high enough to warrant a Watch. In other locations, the chance is less than 1 out of 2 but it will be rather windy, with almost all locations having at least a 1 in 2 chance of gusts past 35 to 40 mph. In the lower elevations, the best chance of hurricane force gusts continues to be on the south side of Casper where some locations have around a 1 in 3 chance. Another area of concern is around Buffalo, but this would be post-frontal toward Tuesday evening. It would also be a fairly brief period here, around 3 hours or less. We will hold off here for now, but it needs to be watched. As for precipitation, the models have trended drier. Again, the forecast is probably the wettest it will be, and most locations will not see much given the strong downsloping flow, especially before sunrise on Tuesday. Wind will decrease Tuesday night as the front moves away and the pressure gradient decreases.

As we head toward Wednesday, we may have the appearance of something we haven't seen in a while. It is those white, crystalline objects that fall from the sky when it is cold. What is that stuff called? Oh yeah, it is called snow! And, it is looking increasingly likely that many areas will see at least some. Of our three official snowfall locations, the Casper Airport hasn't seen an inch of snow or greater since December 27. At Riverton and Lander, it has been two and a half months, since December 2nd and 3rd, respectively. With the Wednesday system, most locations have at least a 2 out of 3 chance of 1 inch or more of snow. The exact location of the heaviest snow will be determined by the movement of a 700 millibar low, and there are still some uncertainties with the movement. There will be some easterly flow to bring in more moisture, Right now, the area from Riverton and Lander to Casper had at least a 1 in 2 chance of 3 inches or more of snow, ending on Thursday morning. The system is a fast mover though, so the chance of 6 inches or more remains low, generally less than 1 out of 4 except in the mountains. So, we may need some highlights for some locations east of the Divide, especially for Wednesday night.

Snow here should come to an end Thursday morning. We should then have some of the coldest temperatures we have seen in a while, especially Thursday night if the sky can clear with the fresh snow cover. Following this, zonal flow should bring dry weather once again. High temperatures will be cooler, especially in the basins where inversions may form. There is still some question on how strong they would be though, given it will now be late February and shorter nights and increasing sun angle will allow temperatures to warm more and melt the snow faster than if this occurred earlier in the winter. There should be a moderating trend into the weekend as well, as the airmass modifies and the snow cover slowly melts.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1052 AM MST Mon Feb 16 2026

Active winter weather and notable aviation impacts are expected at airports across western and central Wyoming over the next 24 hours as a strong weather system moves into the region.

KJAC is likely to see several hours of moderate snow, visibility issues, and mountain obscurations beginning around midnight and lasting until shortly after sunrise. Other sites west of the Divide (KPNA, KBPI, KRKS) will also see periods of snow and wintry conditions.

Those locations that avoid snow and visibility reductions over the next 24 hours will still have to contend with very strong winds. Gusty winds begin overnight for the typical windy locations (such as KCPR) and impact the whole state during the daytime hours Tuesday. Of note for this forecast is KCOD, where wind gusts in excess of 50 kt are currently forecast. In the couple hours before winds mix down, many locations are likely to experience low level wind shear and turbulence as the strong mid-atmosphere winds mix down towards the surface. Winds continue into the early evening hours Tuesday, before tapering off overnight.

FIRE WEATHER

Issued at 247 AM MST Mon Feb 16 2026

A combination of low humidity and a gusty southwest wind will bring elevated to critical fire weather from Muddy Gap through southern Johnson County this afternoon. Elevated to critical fire weather is expected Tuesday with strong to high wind likely for much of the area east of the Continental Divide, although temperatures may be a bit cooler. Cooler and wetter weather on Wednesday and Wednesday night should end the fire weather threat.

RIW WATCHES/WARNINGS/ADVISORIES

Winter Weather Advisory from 11 PM this evening to 5 PM MST Tuesday for WYZ001-012>014-023-024.

High Wind Warning from 2 AM to 5 PM MST Tuesday for WYZ002-003- 010-011-015>018.

Red Flag Warning until 5 PM MST this afternoon for WYZ280-281.

High Wind Warning from 11 PM this evening to 7 PM MST Tuesday for WYZ019-020-030.