textproduct: Cheyenne

KEY MESSAGES

- Dry conditions will persist through the end of the week, but a weak pressure gradient will promote slightly above normal temperatures with winds generally too weak for critical fire concerns.

- A return to more active weather will occur over the weekend and on Monday as a series of weather disturbances combine with adequate low and mid level moisture to produce scattered to numerous late day showers and thunderstorms.

- Somewhat drier air will move into the forecast area for Tuesday and Wednesday, producing a decrease in areal shower and thunderstorm coverage, along with a warming trend.

SHORT TERM /THROUGH FRIDAY NIGHT/

Issued at 113 PM MDT Thu Jun 18 2026

At the upper levels, the region will be mostly controlled by a weak ridge of high pressure that will be shifting over the western US through the forecast period, while at the surface an area of low pressure will be building into eastern Colorado through Friday. Under this pattern, we should continue to see relatively quiet weather for the short term, as our daytime highs in the upper 70's to mid 80's today persists into tomorrow. Dry conditions and limited forcing will keep skies mostly clear, though some chances of precipitation and clouds start to return Friday night into Saturday morning thanks to increasing moisture as surface flow turns easterly and then southeasterly through the day. Finally, dry air will remain firmly entrenched over the western portion of the CWA, but with fuels still reported as green in the region and winds generally light, critical Fire Weather conditions are not anticipated. East of the Laramie Range, while winds may pick up here by Friday as the pressure gradient begins to tighten, the influx of moisture should also preclude the need for highlights as well. Overall enjoy the quiet and fair to slightly warm weather before the weekend when we'll se a more active pattern return.

LONG TERM /SATURDAY THROUGH THURSDAY/

Issued at 113 PM MDT Thu Jun 18 2026

Saturday...A more active pattern develops, while a shortwave trough aloft passes overhead near peak heating, and an influx of low and mid level moisture along a surface trough axis helps to develop a scattered to numerous coverage, 40 to 70 percent coverage of showers and thunderstorms in the afternoon and evening, most numerous east of Interstate 25. Some strong to severe thunderstorms will be quite possible due to forecast instability and wind shear profiles and concur with the Storm Prediction Center, SPC, outlook of marginal to slight risk of severe storms over far southeast Wyoming and western Nebraska, particularly for our southern Nebraska Panhandle counties. Afternoon CAPE, Convective Available Potential Energy will be from 1500 to 2000 J/kg across the Nebraska Panhandle, with bulk shear near 45.

Sunday...While a shortwave trough aloft slides eastward across the Dakotas and Nebraska in the afternoon, its associated cold front will bring some heat relief with 700 mb temperatures near 7C suggesting maximum temperatures in the 70s to lower 80s. Continued adequate low and mid level moisture for scattered late day showers and thunderstorms, closer to the deeper moisture east of Interstate 25.

Monday...Looks like a similar setup compared to Saturday, with a shortwave trough passage in the afternoon, spawning scattered showers and thunderstorms for the afternoon and evening focused along a surface trough axis west of the Wyoming-Nebraska state line. Some strong to severe thunderstorms look likely due to expected instability and wind shear profiles, mainly for southeast Wyoming east of I-25. Upslope flow in the low levels will aid lift for storm generation.

Tuesday...Drier air infiltrates our forecast area under northwest flow aloft, allowing only isolated to widely scattered afternoon and evening showers and thunderstorms, primarily east of I-25. Temperatures slightly warmer than Monday with 700 mb temperatures near 11C.

Wednesday...Ridging aloft moves overhead inducing warmer high temperatures. A surface trough will develop east of I-25, with convergence along the trough aiding in isolated to widely scattered late day showers and thunderstorms east of I-25.

Thursday...Typical "beware" northwest flow aloft will prevail, with decent southeasterly low level winds advecting low level moisture northwestward across our eastern half of counties, and helping to spawn scattered showers and thunderstorms focused along a low level convergence axis. Decent shear and instability suggest possible isolated to widely scattered strong to severe thunderstorms in the afternoon and evening east of I-25.

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/

Issued at 525 PM MDT Thu Jun 18 2026

VFR conditions are expected for the TAF period with generally light and variable winds expected for much of the night at most terminals. Mostly sunny skies are expected during the day Friday with winds increasing during the morning hours.

CYS WATCHES/WARNINGS/ADVISORIES

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