textproduct: Cheyenne

KEY MESSAGES

- Hot, dry, and breezy conditions continue through Sunday night before a much awaited cold front arrives for the start of the week.

- Daily increasing chances for afternoon and evening showers and thunderstorms are expected for Tuesday onward, with beneficial rains most likely on Tuesday, Wednesday, Thursday and Saturday. The summer heat will be moderated and tempered by extensive cloud cover and precipitation coverage much of the extended period with warmer temperatures for Saturday.

SHORT TERM /THROUGH MONDAY NIGHT/

Issued at 1240 PM MDT Sat Jul 18 2026

The upper level ridge is back over us and it shifted back westward. The main area of high central pressure kind of drifts between Central Colorado and New Mexico/West Texas area. This ridge will keep the afternoon high temperatures in the mid to upper 90's east of I-25. For the higher elevations towns west of I-25, the temperatures are still going to fairly warm in the mid to upper 80's. No changes were made to the heat advisory as the southern counties aren't expected to be near or exceed 100 as southerly flow and the higher moisture content are expected to temper the heat a little bit, however they are borderline criteria for a heat advisory since it will take until about 2am to drop below 70 degrees overnight. Ultimately after discussion with our neighboring offices the expansion of the heat advisory will be punting to the night shift to decide with the borderline conditions. Afternoon showers are in store for mainly Carbon county and the mountain tops today and Monday. There are a couple vort-maxes to increase the synoptic lift to develop some showers. The forcing and projected available CAPE look pretty meager outside the few vort-maxes. Hi-res guidance only puts a couple hundred joules over the outer edges of our CWA with the soundings depicting a pretty stout dry layer near the surface. Outside of your regular diurnal showers not much is expected to evolve in the afternoon. Monday, look to be rather similar to Sunday in the aspect of hot and dry conditions for the vast majority east of I-25 and afternoon showers for the mountainous areas with little rain expected to reach the surface. Forcing does shift a little more east with a touch higher CAPE values for Monday afternoon to extended the possible shower/thunderstorm chances to Cheyenne however the thunderstorms have to make it down the mountains first and overcome the extensive dry layer. Showers/ thunderstorm development should be done by the evening with full dissipation of any storms/showers by Midnight.

LONG TERM /TUESDAY THROUGH SATURDAY/

Issued at 1240 PM MDT Sat Jul 18 2026

Tuesday...A decent pattern change ensues with the ridge flattening somewhat, helping monsoonal moisture to spread across our western counties, spawning scattered to numerous showers and scattered thunderstorms in the afternoon, primarily focused west of I-25.

Wednesday...Beneficial rains will become more in areal coverage with s decent increase in low level dewpoints and mid level monsoonal moisture and upslope mechanical southeast winds advecting low level moisture into our counties. Will see scattered to numerous afternoon and evening shower and thunderstorm coverage, most prevalent along the I-25 corridor where lift and orographic lift will be maximized corresponding to the deepest moisture supply.

Thursday...Somewhat drier air infiltrates our counties as the flow aloft turns westerly with some dry air intrusion at low and mid levels, as the surface trough or dryline moves to central Nebraska.

Friday...Ridging aloft becomes more pronounced, though with enough mid level moisture, will see typical isolated to scattered showers and some thunderstorms in the afternoon and evening, mainly west of I-25 and concentrated over the mountains.

Saturday...The ridge becomes less pronounced along with an increase in low and mid level moisture, and with more monsoonal moisture present, afternoon and evening shower and thunderstorm coverage will likely need to be increased as we approach day seven, providing more beneficial rains.

AVIATION /00Z TAFS THROUGH 00Z MONDAY/

Issued at 520 PM MDT Sat Jul 18 2026

VFR conditions will prevail across all terminals for the duration of this TAF period. Winds will diminish through the overnight hours to generally less than 10 knots, and remain so into Sunday afternoon across the southeast Wyoming sites. While, the Nebraska terminals will see an uptick in winds by 17Z Sunday with gusts to around 20 knots.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Heat Advisory from noon Sunday to 6 PM MDT Monday for WYZ101- 102-108. NE...Heat Advisory until 6 PM MDT Monday for NEZ002-095. Heat Advisory from noon Sunday to 6 PM MDT Monday for NEZ003- 019>021-096.