textproduct: Cheyenne

KEY MESSAGES

- A plume of monsoon moisture will arrive today, moderating temperatures and improving rainfall chances through Wednesday.

- Marginal to Slight Risk of Severe Thunderstorms Monday through Wednesday. Strong gusty winds will be the primary threat.

- Heavy rainfall and localized Flash Flooding possible Tuesday through Wednesday night.

- More heat returns for Thursday through Monday, with some near record high temperatures possible for some locations and possible Heat Advisories.

SHORT TERM /THROUGH TUESDAY/

Issued at 216 PM MDT Mon Jul 27 2026

Tonight: WSR-88D radar reflectivity loop and model analysis shows scattered to possible numerous showers, isolated to scattered thunderstorms continuing through early evening, mainly east of I-25. Model trends show showers and some thunderstorms decreasing later tonight. Cloud cover will minimize cooling, acting like a blanket effect. The Storm Prediction Center has reduced the marginal and slight risk area for this afternoon and this evening which seems quite plausible due to extensive cloud cover and reduced instability. Storm movement will be enough to minimize heavy rain threat.

Tuesday: Looks like a more favorable day for scattered to numerous showers and scattered thunderstorms, especially with respect to thunderstorm intensity due to more solar insolation, better low level moisture supply and increased shear parameters, as evidenced by bulk shear values and projected 850/700 theta-e ridge axis placement. Concur with the Storm Prediction Center day 2 outlook showing marginal risk of severe thunderstorms to the right of a line from Laramie to Torrington to Scottsbluff. Marginal risk of flash flooding looks more likely due to weaker steering level winds around 700 mb, 10,000 feet MSL.

LONG TERM /TUESDAY NIGHT THROUGH MONDAY/

Issued at 216 PM MDT Mon Jul 27 2026

Wednesday: Positioning of decent 850/700 theta-e ridge axis, and the proximity of a more decent shortwave trough aloft near peak heating, at least for late July, and the Precipitable Water (PWAT) values from 1.5 to 2 inches, along with impressive shear and instability suggests another round of scattered to numerous afternoon and evening showers and scattered thunderstorms, with a marginal risk of severe thunderstorms to the right of a line from Laramie to Casper in the afternoon and evening from the meteorologists at the SPC, Storm Prediction Center.

Thursday through Monday: Monsoonal moisture retreats out of our County Warning Area (CWA) as a drier and hotter air mass returns producing nearly dry conditions with only minimal chances for isolated to scattered thunderstorms over and near our Snowy, Sierra Madre, and Laramie Ranges due to differential orographic processes. Temperatures will soar once again, especially for Sunday and Monday, with some locations possibly approaching near record maximum temperatures, and perhaps the long standing all time record high temperature of 100 degrees at Cheyenne, that has been achieved four times, the most recent in the 1950s.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 545 PM MDT Mon Jul 27 2026

Scattered showers linger through the Monday evening hours as moist, southwest flow aloft prevails across the region. A few PROB30 groups are included to account for the potential for gusty outflow wind. Coverage generally fizzles leaving only isolated showers by 06Z/Tuesday, followed by decreasing cloud cover and VFR conditions through the early morning hours. However, boundary layer moisture and a clearing sky could allow for a few low cloud decks to form in the western Nebraska Panhandle between 10Z and 15Z/Tuesday. Held off on TEMPO groups and went with FEW/SCT low decks given low confidence as of this writing. Convection develops over the higher terrain of southeast Wyoming between 18Z-20Z/Tuesday. PROB30 groups have been included for KCYS, KLAR, and KRWL to account for the shower and storm potential. To the east, convection may reach these terminals after 22Z/Tuesday, but did not add any mention at this time. For the most part, surface wind speeds 8-16kts from varying directions diminish between 02Z-04Z/Tuesday.

Please see the Aviation Weather Center and/or CWSU ZDV for the latest information on smoke, icing, and turbulence forecasts.

CYS WATCHES/WARNINGS/ADVISORIES

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