textproduct: Cheyenne

KEY MESSAGES

- Marginal Risk of Severe Thunderstorms Tuesday afternoon and evening. Strong gusty winds will be the primary threat.

- Monsoon moisture will remain in place through the middle of the week. Heavy rainfall and localized Flash Flooding possible Tuesday through Wednesday night.

- More heat returns this weekend through Monday, with some near record high temperatures possible.

UPDATE

Issued at 712 AM MDT Tue Jul 28 2026

WSR-88D radar reflectivity imagery and visible satellite imagery along with lightning data show scattered showers and thunderstorms moving east across central and southern Albany County, and affecting Laramie and Bosler through 8 to 9 AM. Boosted thunderstorm coverage based on the aforementioned factors. The rest of the forecast from our midnight shift Meteorologist is in decent shape and no changes made at this time. Aviation wise, the KLAR TAF was updated to include a TEMPO group for thunderstorms through 15Z with thunderstorms impending.

SHORT TERM /THROUGH THURSDAY/

Issued at 135 AM MDT Tue Jul 28 2026

Persistent cloud cover and cooler temperatures on Monday were a nice relief to the heat from this past weekend, although the cloud cover suppressed widespread convection with only widely scattered showers and thunderstorms observed across the area. Some of this activity is lingering into the early morning hours this morning over western Nebraska and near the mountains in Carbon County across southern Wyoming. IR Satellite loop shows slowly decreasing cloudiness over the area, which should result in a more favorable environment for thunderstorms Tuesday afternoon and evening.

Observations across the region show surface dewpoints in the 50s, pretty much everywhere across southeast Wyoming, with dewpoints in the 60s over western nebraska and far eastern Wyoming. Monsoon moisture is in place at the surface and aloft with PWAT above the 90th percentile. This moisture is expected to remain in place through at least Wednesday night. Best chance for thunderstorms appears to be today and Wednesday with cloud cover not as thick and widespread compared to Monday. In addition, a 60 to 70 kt jet is expected to sneak into the forecast area, with some enhanced dynamic lift in the upper levels...but more importantly, increasing midlevel wind shear. Wind shear still appears marginal based on forecast soundings (RAP, NAM, and GFS), but convective parameters and PWAT suggest multicell clusters and maybe a few linear segments with MLCAPE over 2000 j/kg and 0-6km shear around 25 to 30 knots, at times, as a potent shortwave/vort max moves east across the area. Very heavy rainfall is also a concern in this pattern with a marginal risk for flash flooding...especially far southeast Wyoming and the southern Nebraska panhandle. Not going to message this too aggressively quite yet due to the lack of rainfall recently and low soil moisture. However, a day or two of heavy rainfall in the same locations may warrant more aggressive messaging in a day or two. Similar conditions expected on Wednesday but slightly hotter, with very heavy rainfall the primary concern. Shear values drop to below 20 knots even as a broad Pacific upper level trough axis ejects northeast over the Front Range late Wednesday. A little more concerned of flooding on Wednesday and Wednesday night as this trough lifts northeast, but will see what rainfall amounts we receive today. Isolated large or marginally large hail can't be ruled out both days, but appears unlikely at this time with the lack of shear. At this time, nocturnal convection appears more likely Wednesday night with the slow passage of the Pacific upper level trough axis.

For Thursday, models show the upper level ridge axis building over Utah, western Colorado, and western Wyoming behind the Pacific trough. Some drier air should make it into central Wyoming with a slight increase in westerly winds. Further east, models tend to dry things out too fast under weak northwesterly flow, so added 20 to 35 percent POP over the eastern plains for widely scattered thunderstorms. Model soundings show areas along and east of the I-25 corridor hanging onto the low to midlevel monsoon moisture for another day. Hot temperatures on Thursday as the upper level ridge builds northward with highs in the upper 80s to mid 90s.

LONG TERM /THURSDAY NIGHT THROUGH MONDAY/

Issued at 216 PM MDT Mon Jul 27 2026

Thursday night 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 /12Z TAFS THROUGH 12Z WEDNESDAY/

Issued at 545 AM MDT Tue Jul 28 2026

Monsoon moisture plume will remain over the area for at least the next 48 hours. With less cloud cover today, there is a better chance of scattered to numerous showers and thunderstorms, especially further south near the I-80 corridor this afternoon and this evening. Can't rule out some patchy fog late tonight in areas that receive heavy rainfall.

HAZARDS/WEATHER TRENDS: Primary Aviation concern is timing and coverage of thunderstorm activity this afternoon. Winds will remain relatively light out of the east or southeast with occasional gusts of 20 knots. Thunderstorms will form near the Laramie Range, impacting KLAR and KCYS after 20z. These thunderstorms will push over the western Nebraska terminals after 22z and may linger through the late evening hours. Gusty winds and very heavy rainfall are possible which may result in brief MVFR to near IFR VIS.

Kept fog and low CIGS out of the TAF tonight due to low confidence (5% to 10%) in rainfall amounts and coverage. The most likely terminals to see some fog is KSNY and KCYS.

CYS WATCHES/WARNINGS/ADVISORIES

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