textproduct: Western and Central Wyoming

KEY MESSAGES

- A system will bring widespread rain and mountain snow to the area today through Friday.

- The heaviest snow today will be across the western and central mountains, followed by the Bighorns tonight and Friday.

- Lighter snow is expected across most lower elevations west of the Divide today and east of the Divide tonight and Friday. Northern Johnson County is most favored to see up to a few inches Friday morning.

- Strong winds of 40 to 50 mph will be seen across the area today and Friday.

- Overnight low temperatures will drop into the 20s and low 30s tonight and Friday night. Abnormal early season vegetation will be especially susceptible to this cold.

- A warming and drying trend begins Saturday and continues through early next week.

DISCUSSION

Issued at 404 AM MDT Thu Apr 2 2026

The active start to April continues as the leading wave ahead of an approaching low pressure system pushes into Wyoming. This will be most focused on western Wyoming through the morning hours as moisture streams up the Snake River Plain ahead of an advancing cold front. Snowfall rates will be heaviest during this time for the Tetons, Salt/Wyoming Range, and the western Wind River Range as southwesterly low-level flow is maximized, bolstered by a 100+ knot upper level jet. Elsewhere west of the Divide will see a mix of rain and snow depending on elevation. Jackson Hole and Star Valley are most likely to see more persistent snowfall, and we have added a Winter Weather Advisory to account for any snow this morning and more to come later today and tonight. One other area that has potential for snow through the morning and early afternoon is southern Lincoln County where some high resolution models have pinpointed up to a few inches; confidence is not high enough to issue any highlights for now but certainly something to watch.

The low and attendant cold front will begin to progress east over the area after 18Z. While this will mark an overall decrease in available moisture for western mountain snow, precipitation chances will increase everywhere else as synoptic lift ramps up. This will fall predominantly as rain through the afternoon as temperatures remain warm, especially east of the Divide. Wind will also be a factor today as the surface pressure gradient increases in magnitude ahead of the front; southwesterly gusts of 40 to 50 mph will be widespread through the afternoon.

By midnight tonight the low should be centered over the middle of Wyoming. This will mark the beginning of the next phase of this event as moisture is wrapped cyclonically back into the area from the north. Precipitation will accordingly be most focused east of the Divide Friday as an upsloping component is established. Still, enough moisture will return to western Wyoming for another round of moderate snowfall there, and we'll keep the winter highlights going through Friday afternoon. With colder temperatures behind the front, snow will fall east of the Divide even at lower elevations tonight. The Bighorns will be most favored for heavy snow given this setup, especially the northern half of the range. While accumulations across lower elevations will mostly remain on the lighter side (an inch or less), there will be some favored locations that may soon need winter highlights issued. The most likely spot will be northern Johnson County as upslope flow is maximized there Friday morning. This could bring a quick few inches before noon (40 to 60 percent chance of at least 3 inches), and with a strong northerly wind may lead to travel impacts along the I-90 corridor. While confidence is lower, other areas that could see 2 to 3 inches of snow tonight through Friday will be the eastern Bighorn Basin and the Casper area.

Precipitation will wane Friday evening as the low pulls away from the area. Clearing skies should lead to a colder Saturday morning. However, temperatures will warm up quickly as ridging builds back in over the region. This will lead to a warm and dry weekend with temperatures peaking into the 50s and 60s across the valleys and basins. Looking ahead, ensemble guidance favors the warm and dry trend to continue before chances increase for the arrival of the next system midweek.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

Issued at 519 AM MDT Thu Apr 2 2026

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

A weather system will continue to bring bands of snow and rain changing to snow through around 02Z tonight. A heavy snow band will likely (80% chance) will bring IFR to possibly LIFR conditions in vicinity of KJAC between 12Z and 14Z this morning, with wind gusts to 40 knots and a chance (50%) of some lightning. Periods of IFR conditions will remain possible through the day at KJAC as well as at KBPI and KPNA although exact timing of the showers and bands remains difficult. At KRKS, precipitation is expected to be a rain / snow mix through the day, becoming mainly snow after 20Z as colder air moves into the area. Mountain obscuration will be frequent through most of the period, with some possible improvement after 09Z tonight. Wind will be strong at times as well, with the strongest gusts in vicinity of KRKS where gusts over 35 knots will be possible today. Wind will decrease near KJAC tonight but remain gusty at other TAF sites through 12Z Friday.

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

Most terminals will remain largely VFR through the daylight hours, with occasional VFR conditions possible in any showers. Timing of showers remains difficult to pinpoint, so we have elected to continue the PROB30 groups through the day. A few lightning strikes remain possible, especially in vicinity of KCPR. Colder air will move in tonight and change any rain over to snow, with the main impacts at KCOD and KWRL. Wind will become gusty as the weather system approaches and passes. The strongest wind will be in vicinity of KCPR, where gusts to 35 to possibly 40 knots are possible after 18Z. Wind will decrease somewhat tonight but remain elevated. Mountain obscurations will occur at times, especially tonight and especially near the Absarokas and the Bighorn range.

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 until 6 PM MDT Friday for WYZ001-012-014- 015-024.

Winter Weather Advisory until 6 PM MDT Friday for WYZ002-013- 023.

Winter Storm Warning from 6 PM this evening to 6 PM MDT Friday for WYZ008-009.