textproduct: Western and Central Wyoming

KEY MESSAGES

- Strong wind off the east slopes of the Absaroka, Wind River and Bighorn Mountains as well as the Wind Corridor continues this morning into this afternoon with isolated gusts of 50 to 60 mph expected for favored locations.

- Precipitation chances increase across northwest WY this morning. Impacts will be limited with only light snowfall accumulations above 8000ft in the northwest WY mountains.

- Temperatures remain well above normal through the rest of this week, with warmest temperatures (10 to 15 degrees above normal) on Tuesday and Wednesday.

- Several more weak weather systems will bring chances (30 to 50%) for rain and mountain snow showers to western WY Wednesday night into Thursday and again on Friday into Saturday.

DISCUSSION

Issued at 216 AM MST Tue Nov 4 2025

A shortwave will continue to push through the region today, with the main impact being wind. Favored locations will generally be the Cody/Clark area including Chief Joseph highway. 700mb flow of 50 to 60kts is progged with the passage of the trough axis and winds should peak around late morning, before slowly decreasing through the afternoon. Mountain waves are possible as this system moves through. Westerly winds gusting 40 to 50 mph are expected for the aforementioned locations, with occasional gusts to 60 to 65 mph possible (20% chance). As the trough axis slides from west to east through the day, increasing westerly winds are expected across much of the region. Gusts around 30 to 35 mph will be expected for westerly flow favored locations notably from South Pass to Casper and across Sweetwater County. Portions of Bighorn County also are expected see some gusty winds through the afternoon, as well as around Dubois.

With this shortwave, there will be a bit of precipitation as well. Precipitation chances generally increase around sunrise this morning, with 20 to 30% chances persisting across the northwest WY mountains and YNP through much of the afternoon. Given dominant ridging, temperatures remain warmer than normal and thus snow levels will remain at or above 8000 ft, well above valley level. Snowfall accumulations above 8000 ft will be limited (2 to 4 inches at the highest peaks). Valleys could see some occasional rain showers through the day with this system as well, but any amounts will be limited, as the shortwave becomes quickly cutoff from any Pacific moisture flux. Precip chances decrease through the evening and any lingering light showers will end by sunrise Wednesday.

Ridging does continue to dominate the pattern through the rest of the week. That means the above normal temperatures continue. Today and Wednesday will see temps 10 to 15 degrees above normal, despite the shortwave moving through. Downsloping winds will lead to a well- mixed boundary layer today, and thus temperatures will quickly climb into the 60s for many locations east of the Divide today. Though we may flirt with a few daily temperature records, temperatures at this time look to stay below record warm values. The gusty westerly winds and unseasonably warm temps will lead to elevated fire weather conditions across much of the area, especially across southwest WY and the Wind Corridor where RHs will flirt with critical values.

A broad low will start to push down into the Pacific NW Wednesday night which will filter more consistent moisture in zonal flow into western WY. This will come in two waves, the first being Wednesday night into Thursday and the other Friday into Saturday. Amounts for both events look marginal at this time, with the second wave looking to be more potent than the first. Impacts look to remain focused across the western mountains, with snow levels remaining above valley levels through much of the event.

Ridging looks to rebuild by the second half of the weekend and persist into the early next week. Temperatures will moderate back to near seasonal norms Thursday through Saturday with the Pacific moisture influence and more widespread cloud cover. But with the rebuilding ridge, expect temperatures to rebound to much above normal Sunday and especially by Monday.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 1023 AM MST Tue Nov 4 2025

VFR conditions will prevail across nearly all terminals through much of the TAF period. One exception to this will be KJAC where a nearing disturbance is expected to bring in precipitation chances by the start of the period. Ceilings will also begin to lower with MVFR conditions possible throughout the afternoon and evening. Precipitation chances are low, so only VCSH have been added to KJAC's TAF. Conditions are expected to begin to improve at KJAC by the late evening Tuesday with improving ceilings through the overnight. Other terminals will see increasing cloud cover with SCT- BKN ceilings of 100-150 Tuesday evening into Wednesday morning.

The other concern is gusty winds expected across some terminals through the TAF period. The strongest winds look to be at KCPR and KCOD where winds of 20 to 30 knots are expected this afternoon and evening with periodic gusts of 35 to 45 knots possible. Other terminals will see increasing winds as well with speeds around 10 to 20 knots with gusts of 25 to 30 knots. Winds gradually dissipate this evening into the early morning hours on Wednesday. Breezy winds return by the end of the TAF period across mostly all terminals. Mountain obscuration will be likely through much of the TAF period mainly across western ranges especially nearby KJAC. Obscuration may begin to improve by the morning hours Wednesday into the end of the TAF period.

RIW WATCHES/WARNINGS/ADVISORIES

None.