textproduct: Western and Central Wyoming

KEY MESSAGES

- Scattered rain showers and snow showers continue this evening, becoming all snow after midnight. Patchy fog is possible (20-30%) tonight into Tuesday morning, especially for locations that received precipitation recently.

- Below normal temperatures and chances for showers continue from Tuesday through Thursday, although details in placement and amounts of precipitation remain uncertain.

- Dry and warmer weather returns for Friday and Saturday.

UPDATE

Issued at 1230 PM MDT Mon Apr 27 2026

Cloud cover and recent snow keeps cooler temperatures in place today, especially east of the Continental Divide. High temperatures will be in the mid-40s for the most part, with upper 30s around Johnson County. These highs are around 10 degrees below normal for the end of April. Showers, and even an isolated thunderstorm, are possible this afternoon, mainly for southern Wyoming. Precipitation amounts should be fairly limited, but a couple tenths are possible where a heavier shower occurs, most favored for Sweetwater and Natrona Counties as well as around Yellowstone. Snow levels are around 6000 to 7000 feet this afternoon, decreasing tonight. So, a few flakes are possible for lower elevations, with snow in Yellowstone.

DISCUSSION

Issued at 242 AM MDT Mon Apr 27 2026

Most of the winter and early spring has been rather mild, with little snow. However, it has been my luck that I have had to drive to work in the three worst periods to drive, including this evening. Visibility was rather low in blowing snow. As I write this around midnight, we are on the back edge of the heaviest snow in Riverton, but some light snow will linger for much of the night before ending from west to east through the morning. As for the advisory across the Bighorns and northern Johnson County, it is currently still snowing and we will let it go for now. We could end up canceling it early. The football draft was this weekend. So, in association with football injury reports, whether or not to cancel it will be a game time decision. Additional accumulations after sunrise should remain light, generally less than a 1 in 4 chance of an inch or more except across the higher elevations. In addition, much of the snow will melt off today as the strong late April sun crosses the sky. And for your information, solar irradiance is on average now almost 3 times as strong as it is in December around the winter solstice.

Another wave, this one also of southern origin will approach the area this afternoon. Most model guidance keeps the precipitation largely across the southern half of the area with the heaviest precipitation remaining to the south and east of our county warning area. The chances of an inch of snow are less than 1 out of 2 in all locations. Snow showers will continue across the northwestern mountains as well, but again, amounts should remain on the light side. The only place with greater than a 1 in 2 chance of 3 inches or more is in northern Absarokas and here there are basically no roads and few impacts. So, no further highlights will be issued.

Unsettled weather will continue across the area through at least Wednesday and possibly Thursday. A series of shortwaves will continue to move through a longwave trough in place across Wyoming, bringing some rounds of showers through this period. One looks to move through on Tuesday and another on Wednesday, with the one on Wednesday looking a bit more potent. The models continue to have disagreements on placement of the showers and heaviest precipitation though. So for now, we kept POPs generally broadbrushed through the period. With the trough in place and ample cloud cover, temperatures should remain below normal through Thursday.

Ridging should then build over the area for Friday and Saturday, bringing a return to dry conditions and near to above normal temperatures. Another front may approach the area for the end of the weekend with the next chance of showers, but details are still uncertain, as they usually are this far out.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 1044 PM MDT Mon Apr 27 2026

A few showers will continue to move across the area tonight. These will be isolated, with most of the impacts limited to KCPR. IFR ceilings are expected at KCPR even after precipitation ends (likely rain at first, with a transition to snow) after 09Z. Impacts at KJAC are also possible though shouldn't be persistent, with a PROB30 group in place to account for this potential through 12Z. Additional scattered showers will develop again by late Tuesday morning. Confidence on impacts with this activity remains low, however, with KCPR again most likely to see at least brief MVFR impacts Tuesday afternoon. Showers will end after sunset, with skies generally becoming scattered through the end of the period.

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

None.