textproduct: Western and Central Wyoming

KEY MESSAGES

- Mountain snow is forecast across western Wyoming overnight and into much of Wednesday, with the heaviest snowfall rates through 5 AM Wednesday. Mountains within Winter Storm Warnings have a 90 percent chance of one foot or more of snow.

- Western Wyoming valleys will continue to receive precipitation overnight, with higher confidence (70%) it will remain as rain through the overnight hours into Wednesday. Rain will change back to snow by Wednesday afternoon, as the storm begins to wane.

- Wednesday will be the windiest day of the week with widespread 35 to 45 mph wind gusts, and lower elevations of central Wyoming topping 50 mph to near 60 mph.

UPDATE

Issued at 1152 AM MST Tue Feb 24 2026

The atmospheric river is obvious on water vapor imagery, with a good fetch of moisture coming from Pacific around northern California. Heavy snow has been observed over the western mountains, with rates an inch or more an hour. No notable changes were made to the forecast, as the best period of snow production continues through Wednesday morning. See the full discussion for details on this weather system. For wind, have upgraded the watches to High Wind Warnings in anticipation of winds increasing late tonight and tomorrow morning.

DISCUSSION

Issued at 158 AM MST Tue Feb 24 2026

Light snow has already started over northwestern portions this morning. Snow will continue to increase through 12Z this morning, becoming likely and spreading across the western mountains through 18Z. Gusty winds also continue for wind prone locations. Piney Creek, near the Johnson/Sheridan County line, already gusted to 63 mph around 1130pm. Chief Joseph Highway is currently (as of 1225am) blowing around 60 mph and had a 78 mph gust around 945pm. Wind gusts of 40 to 50 mph are also occurring over South Pass/Red Canyon and the south side of Casper. Due to the complex nature of this storm, we will once again split the discussion between the snow and the wind.

Snow...

The overall forecast remains on track will not many changes. Pacific moisture from an atmospheric river (AR) will continue to move over the Cowboy State today. Precipitable water (PWAT) values will rapidly increase, with values of 0.35" to 0.4" becoming widespread by 12Z this morning. This is well above the 90th percentile and toward the climatological maximum. This, coupled with strong isentropic lift, will lead to heavy snow. This afternoon looks to be the period of the heaviest snow, with 2"/hr snowfall rates possible. Snowfall totals of 18 to 24 inches is still in the forecast for the mountains, with locally higher amounts up to 3 feet possible in the Tetons. The forecast challenge continues to be the Jackson and Star Valleys. However, guidance has shifted to snow changing over to rain by early afternoon for both locations. Snow levels will be above 6000ft by this time and increase close to 7000ft before midnight. Precipitation will change back to snow by midday Wednesday, as an incoming Canadian system drops southward. Temperatures will eventually drop back to freezing by mid to late afternoon, as snow begins to end. Areas of ice will likely become a hazard Wednesday night, as standing areas of water freeze overnight. Winds will also increase Wednesday morning, as the main Canadian storm system drops southward. Wind gusts of 35 to 55 mph will be widespread and the snow will become drier (not as heavy and wet). This could lead to very hazardous travel conditions over Teton/Togwotee Passes, as blowing snow will lead to poor visibility conditions.

Wind...

Winds will decrease through the rest of the morning over the warned areas with the threat for high winds (gusts of 58+ mph) ending around sunrise. Thus, will likely expire the warnings for northern Johnson County and the Cody Foothills. Wind gusts of 35 to 45 mph will become more widespread by 18Z from southern Lincoln County to Natrona County and continue through the afternoon. Additionally, will extend the warning for Red Canyon/South Pass through 00Z. These winds will decrease slightly after sunset, with gusts of 30 to 40 mph continuing through the overnight hours Tuesday night. The winds over the Absaroka and Wind River Mountains will increase to 55 to 60 mph through the early morning hours Wednesday.

A Canadian system will rapidly drop southward across the forecast area through the day Wednesday. Strong to high winds are still expected across much of the CWA as a result. The main reason will be due to a 140kt jet max associated with the PFJ and an elongated vorticity axis that will shift southward across Wyoming. This will translate to 700mb winds of 45 to 60kt, which will mix down to the surface. Most areas can expect wind gusts of 40 to 60 mph through the day on Wednesday, with winds increasing by 15Z. Will keep the High Wind Watches in place for the Wind River Basin, Natrona, Sweetwater and southern Lincoln counties. These winds will decrease for most areas after sunset Wednesday evening, but gusts of 25 to 40 mph will continue through the overnight hours for wind prone locations.

The gradient will remain tight enough across the CWA for wind gusts of 30 to 45 mph Thursday afternoon from southern Lincoln County to southern Johnson County, as well as over the mountains. Strong to high winds look to return to the Clark areas and Chief Joseph Pass Thursday night, as a tight temperature gradient of 10C at 700mb develops along the east slopes of the Absarokas. This will result in 700mb winds increasing to 50 to 70kt, producing a significant gap flow wind event. Will keep track of this possible event, as winds could gusts as high as 80 mph. Otherwise, conditions are expected to remain dry Thursday with above normal temperatures remaining in place east of the Divide and over southern portions. Similar conditions return for Friday, as models continue to keep the next Canadian system to the north and only clipping northern portions/Johnson County.

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/

Issued at 930 PM MST Tue Feb 24 2026

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

MVFR conditions expected to start the period west of the Divide with mountain obscuration through the overnight hours and into the afternoon hours Wednesday. Light rain will prevail overnight at JAC/RKS and snow at BPI/PNA. Rain will at least become a mix for JAC after 19Z as the colder air infiltrates the area. Otherwise, IFR conditions possible at PNA/BPI between 09-16Z as winds increase at all locations. Gusts up to 30-35kts at JAC/BPI/PNA and up to 50kts for RKS through 02Z. Winds diminish there after but remain elevated, strongest at RKS up to 30kts through the end of the period.

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

VFR conditions expected east of the Divide as COD/CPR the only TAF sites with a chance for precipitation (10-20%) carrying VCSH after 15 and 21Z respectively. Winds will increase through the overnight hours, peaking up to 45 kts at CPR and 40kts for RIW both by 17Z. All other locations will remain around the 30kt mark, and all TAF sites will see winds diminish after 02-03Z, although elevated through the rest of the period likely to remain most of the overnight hours. Mountain obscuration will occur for areas near the Absarokas and Winds through much of the period as low but VFR ceilings lift to the mid levels for COD along with the rest of the eastern TAF sites.

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 Storm Warning until 5 PM MST Wednesday for WYZ001-002- 012-014-024.

Winter Weather Advisory until 5 PM MST Wednesday for WYZ008- 009-013.

High Wind Warning from 5 AM to 8 PM MST Wednesday for WYZ015- 016.

High Wind Warning from 8 AM to 5 PM MST Wednesday for WYZ017- 019-020-027>030.