textproduct: Western and Central Wyoming

KEY MESSAGES

- Scattered clouds with dry conditions and light winds will continue across the area through the rest of the night.

- Elevated fire weather conditions return Sunday due to very dry conditions.

- A weak frontal boundary sweeps across areas east of the Divide on Sunday, bringing a low chance of showers and thunderstorms (20 to 30%) mainly to higher elevations.

- The next weather system moves across the state Monday and Tuesday, bringing a better opportunity for rain and snow. Confidence remains low in rainfall amounts.

UPDATE

Issued at 1244 PM MDT Sat May 2 2026

Minimal weather concerns today as it remains very dry, warm, and mostly clear. An isolated rain shower is possible (20%) near the Montana/Wyoming border in the mountains. Humidity values will drop quite low this afternoon, with most lower elevations dropping to around 10%. Wind will be gusty along I-25 this afternoon, with light wind elsewhere. Wind will remain light enough to keep fire weather conditions elevated and not critical. Still expecting isolated to scattered rain showers and storms across northern Wyoming Sunday afternoon. Confidence remains low in precipitation amounts for the weather system Monday through Tuesday, but models are trying to highlight an area of higher rainfall and mountain snowfall from the Upper Green River Basin to the Wind River Basin to Casper Mountain down into Sweetwater County. There could be some banding, with stripes of higher precipitation where those bands set up. It does appear that most locations will receive at least some precipitation and most have a good chance (40-50%) of a wetting rain.

DISCUSSION

Issued at 139 AM MDT Sat May 2 2026

A great start to May continues today with high pressure in the region. Skies remain mostly sunny, with only a few high clouds moving in from the west during the afternoon. With the ridge axis pretty much overhead today, temperatures again will be warm for early May, reaching the mid to upper 60s west of the Divide, and the low to mid 70s to the east.

Conditions begin to change late tonight into Sunday as the ridge gets squashed southward. This will open the door initially for a weak frontal boundary to move in from the north Sunday morning. While this front won't have an appreciable temperature difference with the ridge still in the vicinity, there will be a marked increase in moisture, noted by dewpoint increases of 10 degrees and precipitable water (PW) values rising from 0.20 to roughly 0.45 inches by sunrise Sunday. This increased moisture, along with increasing instability aloft, will bring a chance for showers and thunderstorms, mainly across the higher elevations of northern WY, including YNP, during the peak heating hours Sunday afternoon.

Monday and Tuesday will be influenced by a broad trough to the northeast bringing a long fetch of northerly flow. This will help push the front farther south across the rest of the state. The trough will also draw in energy from a cutoff low drifting across southern CA, bringing in more moisture and instability across the state. Most of the precipitation expected with this system still looks to be an overrunning pattern behind the front. Still watching models to see where the front finally settles, which will determine which areas to the north of the front will be the focus of precip Monday night into Tuesday. Models have been fairly consistent in the amounts that will be produced (0.25 to 0.50"), it's just getting the final placement set.

AVIATION /06Z TAFS THROUGH 06Z MONDAY/

Issued at 954 PM MDT Sat May 2 2026

VFR conditions expected through the period. A very weak cold front has moved through the area earlier, with a northerly fetch occurring across the Bighorn Basin and Johnson and Natrona counties. Winds will remain light (11kt or less) across the area through much of the period. FEW-BKN FL180-250 will continue across the area through 18Z.

Gusty winds increase late Sunday morning (16Z-18Z) and through the afternoon. Some isolated showers and thunderstorms are possible (15 to 30 percent chances) for locations east of the Divide (including YNP), with PROB30 groups to cover this timing. Gusty outflow winds up to 40 knots would be the main hazard. Current models keep showers north of KJAC so have continued to leave any mention out of the forecast.

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.