textproduct: Cheyenne

KEY MESSAGES

- Near average temperatures through Wednesday, with a slight warming trend late this week and into the weekend.

- A few thunderstorms Today and Wednesday may produce strong gusty winds, marginally large hail, and very heavy rainfall.

- Daily precipitation chances expected east of I-25. Elevated Fire weather concerns begin Friday for areas west of I-25.

- Strong winds possible Friday and Saturday, but high winds are not anticipated at this time.

SHORT TERM /THROUGH WEDNESDAY NIGHT/

Issued at 146 PM MDT Tue Aug 25 2026

Showers are starting to develop over the Laramie range. Models still depict the southern Panhandle as the area to watch for later this evening. Hi-res models show MuCape values ranging from 1500 to 2,000 joules with some accompanying vort-maxes and some weak isentropic lift. Bulk shear and effective inflow seem kind of marginal at around 20-30 knots meaning there is some severe potential but the storms are likely to be pulsy in nature. NAEFS also shows pockets of elevated moisture across our forecast area as IVT and PWATs remain in the 90th percentile adding to the possibility of heavier rainfall coming from storms that can manage to keep their composure as they push east away from the Laramie range. A Marginal Risk for excessive rain continues today (and Wednesday) along the I-80 corridor and as far north as the North Platte River Valley. Continued to increase POP between 40 to 60 percent for scattered/numerous showers and scattered thunderstorms. Will have to watch the position of the front, since this is where thunderstorms may train over the same area. RAP model soundings also show a pretty stout dry layer near the surface and becomes saturated right around the 3km mark. So any thunderstorm/shower could also produce some gusty winds as the lighter rainfall evaporates before hitting the ground resulting in possibly frequent microburst events.

Similar conditions on Wednesday as another transitory shortwave moves southeast across the same area. Higher boundary layer moisture as well with PWATS approaching the 95th percentile. However, models are showing a bit more CIN below 700mb as the front lifts north as a warm front and stalls. High resolution models are showing a limited coverage of showers and thunderstorms due to low clouds and maybe some fog in the morning. Will have to keep an eye on this trend since Wednesday was looking like the best potential for excessive rainfall and some flooding. Kept POP as is but did lower them slightly further east into western Nebraska. Convective variables look good, with the exception of the low stratus seen on model soundings. Believe high res guidance is underplaying the potential, since good surface convergence is expected with easterly winds east of the Mountains, and a continuation of west to northwest winds across Carbon and Albany counties. Will also need to keep an eye on severe thunderstorms since 0-6km shear will be higher with models indicating MLCAPE of 1000 to 2000 j/kg across the eastern plains.

LONG TERM /THURSDAY THROUGH MONDAY/

Issued at 146 PM MDT Tue Aug 25 2026

An active long term weather pattern looks to be still taking shape. At the upper levels, a strong ridge takes hold of the Western United states limiting our overall wind shear potential through the weekend. Between the two low pressure systems progged to move along the Canadian border, our ridge will limit their influence somewhat, but continued light monsoonal moisture advecting into the area will make it interesting. The overall forecast will be pretty much the same thing will about a 40 percent chance of storms in the afternoon and evening across the area and breezy but calmer mornings. 700mb temperatures look to stay between 13 and 17C meaning the daily high temperatures will be in the 80's for Southeast Wyoming and 90's in the Nebraska Panhandle especially towards the end of the week. There will be a cool down as showers and thunderstorms move over an area so some relief will occur for those who aren't a fan of the summer heat. The Wyoming wind will also start to make an appearance later this week. While not quite high winds yet (except under thunderstorms). The normal afternoon breezes will steadily become a little stronger Friday afternoon and into the weekend. These winds are induced from the slightly tightened pressure gradient as an upper level trough pushes against our ridge about as well as dragging anything across sand paper. So expect breezier conditions especially in the mountains west of I-25 and along I-80.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 1140 AM MDT Tue Aug 25 2026

A surface cold front will push south over Wyoming and into the eastern high plains today. More storms and showers are expected to develop this afternoon over far southeastern WY and push into the eastern plains this evening. VFR conditions are expected to prevail through this TAF period. All terminals except KRWL and KCDR have the PROB30 group with this storm coverage. Locally heavy rainfall and strong winds with gusts up to 50 knots are possible, resulting in brief IFR conditions.

CYS WATCHES/WARNINGS/ADVISORIES

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