textproduct: Western and Central Wyoming

KEY MESSAGES

- High temperatures climb to 10 to 15 degrees above normal Monday as warmer air arrives. Similar daytime highs occur through the work week.

- Mountain snow is forecast across western Wyoming Tuesday and Wednesday, with the heaviest snowfall rates between 5 AM Tuesday and 5 AM Wednesday. Mountains within the Winter Storm Watch have a 70 percent chance of one foot or more of snow.

- Western Wyoming valleys will receive precipitation Tuesday, but with surface air temperatures near freezing, there is low confidence in snow levels. Places like Jackson Hole and Star Valley could (40 percent chance) receive notable snowfall with this event if temperatures remain slightly cooler than currently forecast.

- There will be a prolonged period of very windy conditions along and east of the Continental Divide beginning Monday night and lasting through Friday. Wednesday appears to be the windiest day of the week with widespread 35 to 45 mph wind gusts, and lower elevations of central Wyoming topping 50 mph.

UPDATE

Issued at 102 PM MST Sun Feb 22 2026

The incoming warmer, moist, strong, zonal flow beginning late Monday night and continuing into Wednesday morning has led to the issuance of a mix of winter storm watches and high wind watches across the western mountains. The warmer air leads to high temperatures 10 to 15 degrees above normal Monday, a trend that persists through the week for all but the far west valleys and high deserts.

The leading edge of an atmospheric river (IVT 300-400 kg/ms) reaches the western mountains just prior to 5 AM Tuesday. Favorable isentropic lift combined with orographics leads to a prolonged period of snowfall from southern Yellowstone to the north half of the Salt River/Wyoming Ranges. The heaviest snow falls between 8 AM Tuesday and 5 AM Wednesday and favors the Teton Range, Pitchstone Plateau, and the area around and north of Togwotee Pass. There is a 70 to nearly 100 percent chance of one foot or more of snow in these areas, which necessitated the issuance of winter storm watches. There is close to a 50 percent chance of totals exceeding 18 inches in the Teton Range. This airmass is moist, so this looks possible. The challenge remains regarding valley rain/snow as warm air advection could lead to warmer daytime highs, in turn hindering valley accumulations.

Wind along and east of the Continental Divide will be the other aspect to this incoming event. The initial surge of stronger wind arrives late Monday night and Tuesday across the Absaroka Range and portions of the Cody Foothills. This surge shifts south to the Wind River Range, including Red Canyon, and the Upper Wind River Valley around Dubois during the day. A high wind watch has been posted for these areas, but confidence is marginal. A more westerly component to the wind may hinder wind gust potential in the Lander Foothills, so have kept that zone out of the watch for now. The more widespread wind event arrives Wednesday as a 130kt+ jet and elongated vorticity axis shift south across Wyoming. The chance of widespread 50+ mph wind gusts Wednesday is 30 to 50 percent east of a Cody to Dubois to Rock Springs line. We decided to message this strongly, and wait for a later shift to make a determination on upgrading the first set of high wind watches before creating a second set of watches. Nonetheless, Wednesday will be very windy across a substantial area.

DISCUSSION

Issued at 231 AM MST Sun Feb 22 2026

Today will likely be the calmest day of the week. Temperatures will be 5 to 10 degrees warmer today, rebounding back to near normal levels. Conditions will remain dry, with high clouds this morning giving way to clear skies by the afternoon. Winds will be light for most locations. Exceptions will be the east slopes of the Absaroka, Wind River and Bighorn Mountains and the Wind Corridor east of the Divide (Muddy Gap/Jeffrey City to Casper). Gusts of 25 to 30 mph will occur in these areas. Similar conditions return for Monday, with temperatures 10 to 20 degrees warmer across the area leading to highs in the 45F to 55F range. Gusty winds will impact the previously mentioned areas again, with higher gusts of 35 to 55 mph occurring through the afternoon. Wind gusts of 25 to 35 mph will be more widespread as well, from southern Lincoln County to southern Johnson County. These increased winds will be due to the pressure gradient tightening associated with an approaching storm system that will begin to impact western portions later Monday night.

An atmospheric river (AR) will develop over the PACNW tonight into Monday, as a broad ridge develops over much of the Intermountain West Monday night into Tuesday. This pattern will lead to the core of the PFJ being over the PACNW and Canadian border. At the same time, Pacific moisture from this AR will begin to increase over the region, with the first rounds of snow developing over the western mountains late Monday night. Precipitable water (PWAT) values will rapidly increase between 06Z and 12Z Tuesday, with values of 0.35" to 0.4" becoming widespread across the Cowboy State. This is well above the 90th percentile and toward the climatological maximum. This, coupled with strong isentropic upslope, will lead to heavy snow. There remains a high probability (greater than 70 percent) of widespread snowfall of at least 8 inches over the northwestern mountains (including Yellowstone), while the Tetons and southern Absarokas have a 40-60 percent chance of totals over 15 inches. The chances for snow in the Jackson and Star Valleys are highly variable, as model solutions are waffling on snow levels (which are currently between 6000 and 7000ft). This is likely due to the Pacific nature of the airmass. However, there is up to a 50% chance for 2 inches or more in the Jackson Valley (with higher chances on the north end of the valley between Moose and Moran) and a 10 to 20% chance in Star Valley through the day Tuesday and into Tuesday night.

Gusty winds will also continue over the mountains and increase late Monday night as well, as the gradient continues to tighten as a system begins to drop southward from Canada. 700mb winds will increase to 50 to 70kt between 09Z and 12Z Tuesday, with a strong downsloping signature off the east slopes of the Absaroka and Wind River Mountains occurring by 12Z. This could lead to high winds (wind gusts 60+ mph) at places like Cody, Dubois and Lander. Needless to say, gusty winds will be more widespread with gusts of 35 to 50 mph occurring from southern Lincoln County to Natrona County Tuesday afternoon. Locally higher gusts around 60 mph will occur over South Pass. Caution is advised for travelers here, as well as over Togwotee/Teton Pass, with gusts of 25 to 35 mph occurring with the snow.

The aforementioned Canadian system will rapidly drop southward across the forecast area through the day Wednesday. Strong to high winds will be widespread across the CWA as a result. The main reason will be due to a 130kt jet max associated with the PFJ that will be in place ahead of the system. 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. These winds will decrease for most areas after sunset Wednesday evening, but gusts of 25 to 40 mph will continue for wind prone locations. Moderate to heavy snow will also continue over the western mountains Wednesday, ending by the evening as well, as the main system exits to the south.

Strong gusty winds will continue across the area Thursday in the wake of the storm, as northwest winds persist. Another Canadian storm system could impact the area with cold temperatures and snow by Saturday. Most of the impacts will likely stay east of the Divide if current trends continue.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 952 PM MST Sun Feb 22 2026

VFR conditions prevail over the next 24 hours, but winds will be increasing and becoming gusty at many locations ahead of Monday night's (and Tuesday's) incoming weather system. Most locations will have opportunity for afternoon gusts in the 20 to 30 kt range.

KCOD is worth mentioning in particular, as strong winds in the lee of the Absaroka Mountains could cause notable gusts there after sunset on Monday. Have gone with the more likely 30 kt sustained gusting to 45 kt in the TAF at KCOD Monday evening into the overnight, but that could be higher at times. With 60 to 70 kt westerly winds from around 3000 to 5000 AGL during the much of the night there, occasional gusts in the 50 to 60 kt range can't be ruled out (40% chance).

Precipitation looks to hold off in western valleys (including KJAC) until the early AM hours Tuesday.

RIW WATCHES/WARNINGS/ADVISORIES

Winter Storm Watch from late Monday night through Wednesday morning for WYZ001-002-012-024.

High Wind Watch from Monday evening through Tuesday afternoon for WYZ002-003-015-016.