textproduct: Western and Central Wyoming

KEY MESSAGES

- High temperatures climb to 10 to 15 degrees above normal today 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 Winter Storm Warnings have a 80 to 90 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 this afternoon 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.

DISCUSSION

Issued at 312 AM MST Mon Feb 23 2026

Hope you were able to enjoy the mostly tranquil conditions over the weekend because things just go downhill from here. The warming trend will continue today with temperatures 10 to 20 degrees warmer than Sunday across the area, leading to highs in the 45F to 55F range. Gusty winds will continue to increase over the east slopes of the Absaroka and Wind River Mountains, as well as the Wind Corridor east of the Divide (Muddy Gap/Jeffrey City to Casper), with gusts of 25 to 35 mph. These winds will increase to 35 to 55 mph by early afternoon, as the pressure gradient tightens irt an approaching storm system that will begin to impact western portions later Monday night. The timing for the high winds over the Absaroka Mountains and Cody Foothills has been moved forward to this afternoon, as a result of this approaching system. Strong to high winds look to develop over the Clark area and near Chief Joseph Highway by 2PM (21Z) this afternoon, and spreading to areas west and southwest of Cody after 5PM. The High Wind Watches have been upgraded to Warnings and timings have shifted forward as a result. Due to the complex nature of the upcoming storm, the rest of the discussion will be split between the snow and the wind.

Snow...

An atmospheric river (AR) has begun to move onshore over the PACNW this morning, as a broad ridge develops over much of the Intermountain West today. 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/early Tuesday morning. 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 lift, will lead to heavy snow. Winter Storm Watches have been upgraded to Warnings over the western mountains. Additionally, the western slopes of the Wind River Mountains has been added to the list of warnings and a Winter Weather Advisory for the Jackson Valley has been added as well. Snowfall totals of 18 to 24 inches is expected 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. The chances for snow in the Jackson and Star Valleys remain highly variable, as model solutions continue to depict snow levels in the 6000 and 7000ft range. This is likely due to the Pacific nature of the airmass. Current thinking is temperatures to rise above freezing in the Jackson area, in the middle 30s, Tuesday afternoon and dropping back below freezing around sunrise Wednesday morning. However, if precipitation rates are high enough, this would lead to temperatures to drop below freezing and the rain changing back over to snow. Forecasted liquid precipitation amounts range between 0.75 and 0.9" (with 0.50" of that occurring during the day Tuesday), so this could turn into a heavy snow event for the Jackson area with temperatures hanging just above freezing. This is true for the Star Valley as well, but confidence is 20-30% of this occurring. The north end of the Jackson Valley (from Moose to Moran) is expected to stay as all snow, with amounts close to 8". Winds will 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...

700mb winds will increase to 50 to 70kt after 00Z Tuesday, with a strong downsloping signature off the east slopes of the Absaroka and Wind River Mountains between 03Z and 06Z. Strong to high winds will increase over the east slopes of the Wind River and Bighorn Mountains during this time. Considered adding the east slopes of the Bighorns and northern Johnson County to the Warnings, but do not think the winds will reach criteria. The exception will be the area of I-90 north of Buffalo to the Johnson/Sheridan County line, where gusts up to 60 mph could occur between midnight and 6am Tuesday. Winds will decrease through Tuesday morning over the warned areas with the threat for high winds (gusts of 58+ mph) ending by 18Z. However, gusts of 35 to 45 mph will become more widespread from southern Lincoln County to Natrona County by this time and continue through the afternoon. These winds will decrease slightly after sunset, with gusts of 30 to 40 mph will continue through the overnight hours Tuesday night. The winds over the Absaroka and Wind River Mountains will be higher, with gusts of 55 to 60 mph.

A 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 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. High Wind Watches have been issued 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.

Strong gusty winds will continue across the area Thursday in the wake of the storm, as northwest winds persist. Temperatures will remain above normal Thursday and Friday, despite a northwest flow pattern aloft. Models have trended away from a Canadian system impacting much of the area this weekend, instead only clipping northern portions on Saturday.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 423 AM MST Mon Feb 23 2026

VFR flight conditions are forecast with some gusty winds and largely dry weather before a system makes it's way into the region late in the period. Elevated winds with an occasional gust around 20kts are expected at KCOD and KCPR before winds become predominately gusty this afternoon. There is high confidence that KCOD has the strongest winds with gusts around 45kts after 03Z due to westerly winds aloft strengthening considerably (60kts to 70kts in the 3000 ft to 5000 ft AGL range). Thus, at KCOD, occasional gusts around 60kts are possible from 03Z until the end of the TAF period. Gusts around 20kts to 25kts are forecast at KJAC, KRKS, and KBPI during much of the afternoon. All other terminals can expect winds 12kts or less through the entire TAF period.

As mentioned, a weather system approaches from the west late in the TAF period. All terminals, except KJAC, will remain dry through at least 12Z Tuesday. At KJAC, light snow begins late in the period with a 20% chance of associated MVFR ceilings and visibilities. Given the low chances in MVFR flight conditions, I opted to keep conditions VFR at this time.

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 from 5 AM Tuesday to 5 PM MST Wednesday for WYZ001-002-012-014-024.

High Wind Warning from 2 PM this afternoon to 11 AM MST Tuesday for WYZ002.

High Wind Warning from 2 PM this afternoon to 6 AM MST Tuesday for WYZ003.

Winter Weather Advisory from 5 AM Tuesday to 5 PM MST Wednesday for WYZ013.

High Wind Warning from 11 PM this evening to 5 PM MST Tuesday for WYZ015-016.

High Wind Watch from late Tuesday night through Wednesday evening for WYZ015-016.

High Wind Watch from Wednesday morning through Wednesday afternoon for WYZ017-019-020-027>030.