textproduct: Cheyenne

KEY MESSAGES

- Dry conditions 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 255 PM MDT Wed Jun 17 2026

While a final critical day for fire weather conditions is ongoing east of the Laramie Range, overall the weather is winding down on this fair June day as winds are beginning to relax while temperatures remain mild to slightly warm. Once Red Flag Warnings are allowed to expire later this evening, sensible weather concerns will become nil thanks to weak ridging beginning to overspread the western US. For temperatures, since this feature will be slow to overspread alongside the cold front we just had push through, overall highs will remain slightly above normal, with temps generally in the 80's for the next two days. For winds, this system will bring a weak pressure gradient that should promote lighter winds overall, with some periods of breeziness in our CWA that isn't unusual for our area. The weather pattern becomes a bit more interesting Friday evening into Saturday morning though as the ridge begins to shift eastwards and we start to see the region begin becoming unstable as we move into the weekend. Some overnight showers or storms may move across the Nebraska Panhandle, a precursor to stronger activity on Saturday, but the overall real concerns begin cropping up in the long term period.

LONG TERM /SATURDAY THROUGH TUESDAY/

Issued at 255 PM MDT Wed Jun 17 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 possible due to forecast instability and wind shear profiles.

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. Upslope flow in the low levels will aid lift.

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.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 1134 AM MDT Wed Jun 17 2026

Brisk northwest flow aloft continues. A cold front passes by the terminals today and this evening.

Wyoming TAFS...With minimal low and mid level moisture, high confidence that skies will be clear. Sufficient gradients suggest wind gusts to 23 to 38 knots until late this evening, with winds subsiding afterward, then gusting up to 25 knots at Rawlins and Laramie after 15Z Thursday.

Nebraska TAFS...Low and mid level moisture will be scant, high confidence in clear skies prevailing, with the exception of scattered to broken clouds near 11000 feet at Chadron until early this evening. Sufficient surface pressure gradients suggest winds will gust to 38 knots until 02Z to 03Z.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Red Flag Warning until 10 PM MDT this evening for WYZ417-418- 430>433.NE...Red Flag Warning until 10 PM MDT this evening for NEZ434>437.