textproduct: Cheyenne

KEY MESSAGES

- Record breaking heat continues Sunday across the area.

- Another round of widely scattered afternoon and evening showers and thunderstorms is anticipated Sunday, which will have the potential to produce gusty winds and lightning.

- A plume of monsoon moisture will arrive on Monday, moderating temperatures and improving rainfall chances through Wednesday.

SHORT TERM /THROUGH MONDAY NIGHT/

Issued at 315 AM MDT Sun Jul 26 2026

Hot temperatures remain the primary forecast concern today across the area. Showers have waned over the last few hours, but we still have a few weak radar echos mainly over the Nebraska panhandle early this morning, though rainfall is likely not reaching the ground. However, cloud cover and breezy conditions continuing in the area are leading to exceptionally warm nighttime temperatures, especially in western Nebraska.

Expect a very quick warm-up this morning as the heat wave reaches its peak aloft. Surface winds are expected to be northwest across most of the area this morning, which may impact the precise surface temperature recorded at several locations. Yesterday's winds were southerly for the most part, which provided downslope warming enhancement in the Chadron area. That will not be the case today, but northwest is a better downslope wind direction for several other locations, including Cheyenne. Overall, expect highs today to be very similar to yesterday, in the low to mid 90s at Rawlins and Laramie, upper 90s in Cheyenne, and 100s below about 5500 feet in elevation. Forecast highs exceed daily records at all of our climate sites today, with the exception of Rawlins. In addition, several locations have a slim but non-zero chance to tie or break all-time warmth records. For example, in Cheyenne, the forecast high is 98 degrees, but the 90th percentile is 100 degrees (which matches the all-time record). Thus, Cheyenne has approximately a 10% chance to tie the all-time heat record today. Scottsbluff, Alliance, Sidney, and Laramie all have between a 5% and 10% chance to exceed their all- time records, which is 110 degrees at Scottsbluff and Alliance, 108 degrees at Sidney, and 94 degrees at Laramie.

Considering that the atmosphere is really not all that dry during this heatwave, we will easily reach convective temperatures once again Sunday afternoon. Synoptic forcing for ascent is a little weaker than it was yesterday, meaning that we will probably get a slower start to thunderstorm activity with overall slightly lower coverage. One exception to that is near the mountains of southern Wyoming, where probabilities for rainfall are a touch higher than yesterday. The main concerns with today's activity will be lightning and gusty/erratic winds, though a brief downpour and small hail cannot be ruled out. Again today, the storms will not be strictly dry, but the winds may be more notable than the rainfall. Despite a slower start and lower coverage, don't be surprised to see widely scattered showers and isolated thunderstorms continuing well into the evening and possibly even after midnight.

The heat will finally begin to ease on Monday as another surge of monsoon moisture pushes into the area. Recent model trends have accelerated the arrival of moisture aloft, such that it may be more like Monday morning rather than afternoon. As a result, the latest official forecast has much more cloud cover and even possibly a few showers across the area Monday morning. This has also moderated high temperature forecasts Monday afternoon. The latest forecasts have highs only around the climatological 90 to 95th percentile, while we usually reserve Heat Advisory headlines for the 99th percentile and higher. Therefore, we really cannot justify continuing heat headlines into Monday with probabilities for reaching local criteria generally at 25% or less. With this morning's update, we have modified the expiration time of the Heat Advisory and Extreme Heat Warming to 9PM today instead of 9PM Monday to account for the reduced high temperature forecast on Monday. With the arrival of the next monsoon plume, expect scattered to numerous showers and thunderstorms Monday afternoon and evening, with notably higher probabilities for appreciable rainfall compared to the weekend. A few isolated strong to severe thunderstorms are possible as well.

LONG TERM /TUESDAY THROUGH SATURDAY/

Issued at 315 AM MDT Sun Jul 26 2026

Plentiful monsoon moisture is expected to remain in place over the area for at least Tuesday and Wednesday as temperatures moderate a little closer to seasonal averages. We will still be warmer than average, but perhaps by just 3 to 5 degrees compared to 10 to 12 degrees. Ensemble mean precipitable water remains at or above the climatological 90th percentile during this period, suggesting daily chances for at least scattered if not numerous to widespread showers and thunderstorms. Currently, ensembles are most optimistic about rainfall chances on Tuesday for the majority of our area. It's too early to get into specifics concerning storm mode and severe potential at this time, but the environment appears to support a few isolated strong to severe thunderstorms each day.

A pattern change is expected to occur across the western CONUS on Thursday. A shortwave trough riding over the top of the ridge will push across the area. Models are in fairly good agreement showing upper level winds turning more westerly across much of the I-80 corridor and Great Basin region, advecting much drier air into the area and suppressing monsoon moisture to the south. Meanwhile, the upper level ridge will try to retrograde back to the west and broaden itself significantly further to the west. Therefore, we will probably completely lose our tap to the monsoon by the end of the work week. Recycled moisture and a few upper level shortwaves moving over the top of the ridge may still keep isolated to widely scattered showers and thunderstorms in the forecast, but the outlook is not very optimistic for widespread rainfall. As the ridge sets up over the southwestern US and amplifies again, we can expect another warming trend to gradually nudge temperatures upward into next weekend.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 529 AM MDT Sun Jul 26 2026

Winds are expected to settle on northwest by mid-morning today with occasional gusts to 20 knots anticipated. Winds will turn more north and then northeast over the High Plains as the day progresses. Look for another round of widely scattered high- based showers and thunderstorms this afternoon and evening. Coverage will be a little less than yesterday. Expect this to kick off early afternoon around LAR, spread to RWL, CYS, and possibly BFF by mid to late afternoon, and then further east during the evening hours. While a brief VIS drop due to rainfall is possible, the primary impacts are expected to be gusty and erratic winds and vicinity lightning.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Heat Advisory until 9 PM MDT this evening for WYZ101-102-107- 108-118-119. NE...Extreme Heat Warning until 9 PM MDT this evening for NEZ002- 095. Heat Advisory until 9 PM MDT this evening for NEZ003-019>021- 054-055-096.