textproduct: Cheyenne

KEY MESSAGES

- Shower and storm chances are expected through the weekend. Strong to severe wind gusts will be possible, with moderate to heavy rain likely.

SHORT TERM /THROUGH SUNDAY NIGHT/

Issued at 237 PM MDT Fri Aug 28 2026

An active afternoon is expected with showers already showing up on radar early this afternoon. Coverage of showers will increase as the day progresses and the shortwave moving through the ridge enters Wyoming. Storms are not likely to be severe given a lack of strong instability and shear. However, given the dry low-levels from hot temperatures under the ridge, model soundings show profound inverted- V profiles. DCAPE values are over 1000 J/kg, so strong to severe wind gusts will be possible in any shower and storms this afternoon and evening. Cannot rule out some marginally severe hail in the Nebraska panhandle later today as there could be some pockets of higher instability due to ample sunshine. For the most part, showers and storms will be more of a nuisance than anything. Showers will dwindle this evening, but could linger into the overnight hours.

Saturday looks like another active day with models showing multiple waves of precipitation moving through the forecast area and good coverage of storms. A stronger push of monsoon moisture will arrive Saturday as the ridge axis shifts further eastward into the center of the country. The environment looks similar to Friday, with soundings showing little shear and instability. Inverted-V profiles are still present with elevated DCAPE values, so strong to severe wind gusts will still be the primary threat in any showers and storms. Hi-Res guidance shows the first and stronger wave of storms moving into the CWA during the afternoon hours. The second wave will be later in the evening and be more stratiform in nature. Moderate to heavy rain can also be expected with the monsoon push, although PWAT values are nothing abnormal for this time of year according to NAEFS. Most shower activity will die down before midnight.

More of the same can be expected for Sunday with the ridge axis still in the center of the country. Instability and shear remain roughly the same, with model soundings continuing to show mostly inverted-V profiles. As a result, Sunday will likely be similar to Saturday, with storm chances possible during the afternoon and evening hours.

LONG TERM /MONDAY THROUGH THURSDAY/

Issued at 237 PM MDT Fri Aug 28 2026

A fairly stagnant synoptic weather pattern will last through much of next week. Looking at the big picture, ensembles are in strong agreement showing the upper level ridge migrating eastward, and setting up over the southern Plains or southeastern US for much of next week. A series of fairly potent upper level lows will move into the West Coast throughout the period as well. That leaves our area under steady southwest flow for much of the week.

Beginning on Monday, model guidance depicts a notable shortwave trough ejecting to the northeast out of the monsoon region. This will be accompanied by a surge in moisture which should support another round of scattered PM showers and thunderstorms. An early look at the overall setup suggests a typical monsoonal thunderstorm pattern with good forcing, but unimpressive instability. PoPs are currently around 30 to 50%, generally the scattered category, with locally heavy rainfall possible due to precipitable water remaining quite high. The limited instability presents a failure mode though. Several ECMWF ensemble members show heavy rainfall failing to make it far enough north to reach our area, likely due to the lack of instability, while GEFS members as a whole are more aggressive on thunderstorm coverage. Monday also looks like the coolest day of the week, with highs generally near seasonal averages.

Beyond Monday, precipitation chances look more limited but will not disappear entirely. Precipitable water looks to remain elevated for most of the week with the stubborn upper level pattern continuing to bring in a good fetch of monsoon moisture. Expect at least isolated PM showers and thunderstorms every day, but coverage should be more limited than the more potent monsoon surge over the weekend. PoPs remain generally in the 10 to 20% range each day of the upcoming work week. While the core of the upper level ridge will remain southeast of our area, expect a slow warming trend through the week, with highs generally around 5 degrees above seasonal averages. Southwest flow aloft will also support regular breezy to windy conditions in the typical areas of Carbon, Albany, and Converse counties, leading to continued elevated fire weather conditions.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1138 AM MDT Fri Aug 28 2026

Gusty showers and thunderstorms are the primary aviation concern today. Abundant moisture moving in aloft will lead to scattered showers across the area. Multiple rounds are possible during the afternoon and evening hours, possibly continuing after midnight in Wyoming too. However, most thunder should be in the afternoon and early evening hours with showers favored after. PROB30 groups were introduced at most terminals to account for the possibility of strong, gusty winds. Confidence is lower in these storms being able to produce rainfall heavy enough to reduce the flight category, but brief MVFR to IFR will be possible in locally heavy downpours.

Otherwise, expect breezy westerlies gusting 20 to 30 knots in Wyoming today. This may continue overnight, particularly at RWL, while other terminals can expect lighter winds (outside of the gusty showers). Winds will pick up at all terminals mid Saturday morning with gusts of 25 to 35 knots in Wyoming and 20 to 25 knots in Nebraska.

CYS WATCHES/WARNINGS/ADVISORIES

WY...None. NE...None.