textproduct: Western and Central Wyoming

KEY MESSAGES

- There remains a slight chance for patchy fog (20% chance), across portions of Sweetwater County and toward South Pass. Any fog is expected to lift by 10am.

- Light snow (30-60% chance) will occur over the far western mountains, including Yellowstone today and tonight. Little to no accumulations are expected, except 2 to 3 inches over the Tetons and southwestern Yellowstone.

- West-northwest winds will occur over southern portions and the Wind Corridor today. Locally higher gusts up to 45 mph will occur near Cody and the Upper Wind River Basin.

- Windy conditions, with gusts of 30 to 45 mph, will be in place for much of the forecast area through the next 7 days.

- Strong to high winds will be possible Sunday for the Cody Foothills and east slopes of the Absaroka Mountains.

DISCUSSION

Issued at 153 AM MST Sat Mar 7 2026

Dry conditions and clear skies are currently in place across the CWA early this morning. Some low clouds (< 3000ft) continue across portions of Sweetwater County and over South Pass. These clouds are expected to last through 15Z, before scattering out. There is a 50% chance for these ceilings to drop below 1000ft between 12Z and 15Z over areas north of Rock Springs toward Farson.

Northwest flow aloft will be in place today, as a strong ridge over the EPAC begins to fold over the PACNW. Clouds will increase over northwestern portions by sunrise this morning, leading to increased chances of 30-60% for snow showers over the far western mountains. Snowfall amounts will be meager for most of these locations (up to an inch), but 2 to 3 inches will fall from this afternoon and tonight over the Pitchstone Plateau and the Tetons. Conditions will remain dry elsewhere across the forecast area, with west wind gusts of 25 to 35 mph returning across southern portions and the Wind Corridor (Rock Springs to southern Johnson County). Slightly higher wind gusts up to 45 mph will occur near Cody and the Upper Wind River Basin, with the winds near Cody lasting through the overnight hours tonight. The latter winds could reach the Riverton area late in the afternoon, but with slightly lower gusts around 35 mph. These winds will continue through the evening and begin to decrease after 06Z. Above normal temperatures will return east of the Divide as a result of these winds.

The main weather hazard for the CWA in the next 7 days will be wind. Windy conditions will impact much of the CWA each day, with areas of strong to high wind (warning-level criteria of 58+ mph) occurring here and there. The mechanism behind these winds will be a strong 140+kt PFJ. This jet will be the reason the ridge is folding over today and will flatten by Sunday from the "weight" of all this energy.

The jet will make its way over southern British Columbia as the ridge flattens. The right front quadrant of the jet will be over southern MT by 12Z Sunday, pushing southward over far northern portions through the day. This will result in a strong downsloping signature developing between 09Z and 12Z Sunday. This is marked by a tight 700mb temperature gradient along the east slopes of the Absaroka and Wind River Mountains, ranging from 5C to minus 6C over the mountains. 700mb winds also increase to 50kt in this area, indicating the potential for strong gap flow near Clark and Chief Joseph Pass. Will issue High Wind Watches for the Absarokas and Cody Foothills as a result. Otherwise, similar conditions from today will return Sunday with light snow continuing over portions of Yellowstone. Gusty west to northwest winds will return to much of the same areas, with gusts of 25 to 45 mph being widespread. The focus for the higher winds will be over the western mountains and east of the Divide. The east slopes of the Wind River and Bighorn Mountains will also have gusts of 50 to 60 mph. Above normal temperatures will also return as a result of these windy conditions. Areas east of the Divide will be in the 60s, with a few locations in eastern Johnson County approaching 70F.

A more zonal flow pattern will be in place Monday with the PFJ extending from the PACNW to the Great Lakes. Although the core of the jet will be north of the Cowboy State, the gradient will remain tight with widespread 30 to 50kt 700mb winds over much of the CWA. West to northwest winds, with gusts of 35 to 45 mph look to be widespread over much of the area as a result of these conditions. Upper level convergence and strong downward motion will continue over the east slopes of the Absaroka and Wind River Mountains, leading to wind gusts of 60 to 70 mph (some models are indicating locally higher gusts approaching 80 mph). Light snow will be possible over northwestern portions due to orographic flow and limited Pacific moisture, but accumulations look to be minor at this time. Temperatures will continue to be well above normal for early March, as the winds keep the atmosphere well mixed.

Light snow will continue into Monday night and Tuesday, as the upper level flow over northwestern portions becomes more cyclonic as a cold front slowly drops southward from MT. The front will slowly progress southward through the day Tuesday, reaching the WY/CO border by 06Z Wednesday. Winds will also decrease substantially Monday night as a result of the front. However, they will increase again over central and southern portions in the wake of the front. In addition to the front's slow progression, northern portions will have the best chances for snow. Temperatures will remain near seasonal levels as a result of the front, while central and southern portions remain at or slightly above normal. Most of the snow will be over the northern mountains and east of the Divide, with little to no accumulation occurring in the lower elevation. This will due to the warmer conditions over the next 3 days and higher March sun angle. Initial indications show 3 to 6 inches over the Bighorns, with most of this occurring on the northern end and 1 to 3 inches over northern Johnson County.

Dry conditions return Wednesday, as a ridge rebuilds over the Great Basin and the storm from Tuesday strengthens over the Great Lakes and mid-Mississippi Valley. Breezy to windy conditions look to return as well, with elevated fire weather conditions across areas east of the Divide. This trend of widespread windy conditions, and possibly high winds in more wind prone locations, looks to continue Thursday and Friday as the PFJ becomes somewhat zonal (from the PACNW to the Midwest) and feeds into the Tuesday/Wednesday storm system as it moves over the Northeast CONUS. This keeps the gradient tight over the Cowboy State with a 160kt jet max over eastern MT.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 305 AM MST Sat Mar 7 2026

Largely VFR conditions are expected through 12Z Sunday. The one exception will be in northwestern Wyoming where some local MVFR ceilings and mountain obscurations will be possible after 18Z today, mainly over Yellowstone Park and possibly the northern Tetons. I can't rule out a shower in vicinity of KJAC but with the chance is small enough (around 15 percent) that we will leave it out of the forecast for now. A few locations may see patchy fog or low clouds, especially that saw measurable snow. However, not enough confidence (20 percent) to include in TAFs at this point.

The main concern over the next 24 hours will be gusty to strong wind, mainly at the more wind prone TAF sites, KCOD, KRKS and KCPR. Wind gusts to around or over 30 knots will be possible at all three, with the strongest near KCPR where a few gusts to 40 knots will be possible after 19Z this afternoon. At other TAF sites, wind gusts should remain below 18 knots.

RIW WATCHES/WARNINGS/ADVISORIES

High Wind Watch from Sunday afternoon through Sunday evening for WYZ002-003.