textproduct: Cheyenne

KEY MESSAGES

- Lower coverage of showers and thunderstorms today, mainly further south near the Colorado border and western Nebraska. Brief strong gusty winds and locally heavy rainfall expected with this activity into this evening.

- Daily shower and thunderstorm chances continue Monday through the end of the week with slightly above average temperature expected until Thursday.

SHORT TERM /THROUGH MONDAY NIGHT/

Issued at 155 AM MDT Sun Aug 23 2026

Current KCYS radar loop shows remnant convective activity weakening early this morning across western Nebraska as the low to midlevels stabilize for the rest of tonight. Will need to monitor the potential for fog with weak south winds and near saturated conditions near the surface. Otherwise, still getting some brief wind gusts of 45 to 55 MPH with the left over convection, but that should end shortly. Disturbance aloft, which aided in most of the convection initiation on Saturday, will continue to push east early this morning and eventually into central and eastern Nebraska by sunrise. With slightly drier and more stable air behind this shortwave disturbance, expect coverage of showers and thunderstorms to be considerably less today. Expect dewpoint to fall into the upper 30s and 40s along and west of the I-25 corridor, possibly as far east as far western Nebraska. No notable forcing today as the flatten ridge amplifies slightly this afternoon. Isolated to widely scattered thunderstorms expected today, but mainly further south along and near the I-80 corridor. Increased POP a bit across western Nebraska with the surface moisture remaining in place. There is more shear across this region as well, so can't rule out a few strong to marginally severe thunderstorms. Coverage of severe thunderstorms will be limited, just like on Saturday. Otherwise, surface winds are expected to increase out of the west with gusts of 30 to 45 MPH possible, especially across southeast Wyoming near the wind prone areas and west of the I-25 corridor.

For Monday, similar convective environment compared to Sunday but with more midlevel forcing and a bit more low level convergence near the Laramie Range. These factors will help convection initiation which high resolution models all show into the mid to late afternoon and through the evening hours. Increased POP between 25 to 40 percent, especially further south along the Interstate 80 corridor and the mountains. As we head into the evening hours, expect enhanced moisture advection and convergence near the surface as surface winds shift into the east across the eastern plains. With inverted V soundings for much of the day, expect any thunderstorms to produce gusty winds into the evening hours. SPC introduced a Marginal Risk of strong to severe thunderstorms, mainly for strong outflow winds. Remaining very warm or hot during the day with highs in the mid 80s (west) to mid 90s east of the Interstate 25 corridor.

LONG TERM /TUESDAY THROUGH SATURDAY/

Issued at 130 PM MDT Sat Aug 22 2026

Moving into the work week we'll start off on the hot side with a high pressure ridge firmly in control of the Western US. While temperatures will cool just a couple of degrees compared to Sunday, highs still sit warmer than average by around 5-8 degrees. A cold front will be approaching the region with another round of afternoon showers and thunderstorms on tap including locally stronger to weakly severe activity possible. By Tuesday though a backdoor cold front will offer very meager respite as highs drop by around 2-6 degrees, closer to near average but still above by up to a few degrees. Similarly, moisture will continue to remain just above average at around 120-140% of average, equating to PWAT values of 0.75-1.25 inches. While not impressive by any stretch of the imagination, this should continue to fuel daytime thunderstorms with a marginal risk of severe activity. Wednesday through the end of the week look to be largely similar with a steady warming trend, bringing us back to temperatures similar to Monday alongside continued daily afternoon thunderstorm risk under westerly to northwesterly flow. Drier air will slowly infiltrate through the week though, and this will begin to steadily increase our fire weather risk with elevated conditions at least by Friday. Anyone expecting an early end to summer will be sorely disappointed in the last full week of August.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 545 AM MDT Sun Aug 23 2026

Potent upper level disturbance will push east of the Front Range this morning, with some drier air moving into the area. Lower coverage of thunderstorms expected this afternoon with breezy to locally windy conditions expected over central Wyoming.

HAZARDS/WEATHER TRENDS: VFR conditions will prevail over the next 24 hours. Low CIGS and fog can't be ruled out early this morning, but confidence remains low enough to keep out of the eastern plains TAF. Isolated to widely scattered thunderstorms expected after 20z, but coverage will be minimal for most terminals, so left out any mention of thunder. The only exception is KCYS which has the best chance to see an afternoon thunderstorm, so added PROB30 mention between 20z and 23z. KRWL and KLAR will likely experience westerly winds gusting between 30 to 35 knots at times.

CYS WATCHES/WARNINGS/ADVISORIES

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