textproduct: Western and Central Wyoming

KEY MESSAGES

- Scattered shower activity continue into early Tuesday morning with some mix to changing over to snow possible (20-30%).

- Showers become more widespread into Tuesday afternoon with a full changeover to snow overnight into Wednesday morning as temperatures will be 10 to 20 degrees cooler than average.

- Winter weather advisories have been added for the Green Mountains to eastern Sweetwater County due to light accumulating snow and gusty winds up to 30 to 35 mph.

- Freeze watches have been upgraded to freeze warnings for lower elevations east of the Divide for Wednesday morning.

- Dry and warming trend into the weekend and next week.

DISCUSSION

Issued at 200 AM MDT Tue May 5 2026

Increasing cloud cover pushing in from the north as depicted on IR. L/W trough extends with a positive tilt northeast to southwest to the upper level low across the Sierra Nevadas. This has given way to increasing divergence aloft through northern Utah to southern Wyoming as the low deepens with models having it embedded into L/W pattern. The PFJ becomes contorted across this area with much of the PVA anomaly extending across southern portions of the CWA and points east into the High Plains. As such, winter weather advisories have been added across the Green Mountains and eastern Sweetwater County for later Tuesday evening into Wednesday morning as this trough pushes northeast. Winds will be the main driver with this area seeing gusts up to 30 to 35 mph likely creating a crosswind across I-80 and Highway 287 through Jeffrey City to Muddy Gap. Likely snow amounts won't be much but expecting around 2 to 3 inches (60-70% confidence) indicative of some blowing snow to hinder visibility in these areas.

Otherwise, ongoing shower activity through southern Bighorn Basin into eastern portions of Fremont County. Models have pushed back the onset of more widespread, but CAMs are not handling this very good and thus, showing PoPs to QPF being well overdone with the NBM runs. What precipitation is going currently looks to mix in with a bit of snow to changing over through sunrise Tuesday morning but not expecting an accumulation at this point in time to hinder morning commutes with temperatures still above the freezing mark. With ample cloud cover throughout the day and reinforcement of cooler air, expect temperatures to show not much of an afternoon warmup struggling to break the 40 degree mark for many basins east of the Divide.

Better chances for precipitation changing over to snow Tuesday evening after sunset and overnight as the aforementioned upper level low becomes progressive as it passes to the south. This model shift as pulled back some QPF amounts as the more ample accumulations will be eastward and into Colorado extending to the High Plains reaching as far as western portions of Nebraska and Kansas. Lingering precipitation into later parts of Wednesday but most activity will end as the upper trough pushes east and lifts out of the state. Wednesday morning will be the coldest of the week, with freeze warnings upgraded for many lower elevations east of the Divide.

Beyond Wednesday, expect upper level ridging to build in from the west with increasing convergence aloft. This will push the main finger of the PFJ to push northeast for the Dakotas and into the Great Lake/Missouri River Basin areas of the country. Models have backed off on this extending a bit southwest for northeastern portions of the CWA for Saturday, looking to remain at best, far northeastern parts of the state itself. Ridging and northwest flow dominates the weather pattern for the weekend and beyond into next week with dry conditions and a warming trend in store going forward.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 1045 PM MDT Mon May 4 2026

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

Precipitation will begin to develop west of the Divide shortly after the start of the period. KPNA, KBPI, and KRKS will have the best chances of seeing prevailing precipitation through the morning hours with MVFR to IFR conditions at times. KJAC may see a stray shower or two but overall should remain VFR with near MVFR ceilings at times overnight. There looks to be two rounds of precipitation with the first arriving early this Tuesday morning around 07Z at KPNA and KBPI. While KRKS sees showers move in later in the morning around 14Z through the early afternoon. A brief break is expected during the late morning through the early afternoon with a few showers possible at times. The next round of prevailing precipitation arrives near 00Z Wednesday and looks to persist into the end of the TAF period. KJAC may see a shower at this time but chances remain low and the terminals should see minimal impacts. Winds will be gusting 10 to 25 knots during the day Tuesday with stronger gusts nearing 30 knots at KRKS.

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

Precipitation has begun to move into portions of central WY this evening and is expected to begin to impact terminals shortly after the start of the period. KCPR, KLND, and KRIW look to see the most impact with periods of MVFR to IFR conditions. KWRL and KCOD likely see periods of MVFR conditions mainly due to lowered ceilings but overall precipitation chances look much lower. The first round of precipitation will develop early Tuesday morning at KLND, KRIW, and KCPR. MVFR to IFR conditions will be possible through the overnight with precipitation gradually ending shortly after 12Z. KLND may see some showers linger nearby through the remainder of the morning into the early afternoon. Another round of precipitation moves through later in the afternoon around 21Z Tuesday. This second round looks to bring precipitation chances to all terminals possibly through the end of the TAF period especially at KLND, KRIW, and KCPR. MVFR to IFR conditions are likely to develop and persist from 21Z Tuesday through the end of the period at these terminals. Winds will be gusty at times ranging from 15 to 25 knots at times.

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

Freeze Warning from 1 AM to 9 AM MDT Wednesday for WYZ003>006- 010-011-017-018-020.

Winter Weather Advisory until 1 AM MDT Wednesday for WYZ009- 015.

Winter Weather Advisory from 6 PM this evening to 7 AM MDT Wednesday for WYZ019-030.