textproduct: Cheyenne

KEY MESSAGES

- Scattered to numerous showers and thunderstorms will continue through Thursday evening. Localized flash flooding remains possible.

- Warmer air will return to the area Friday into early next week. Near record high temperatures are possible Saturday through Monday.

- Dry weather is expected Friday with a few isolated storms Saturday and Sunday. Monsoon moisture will return Monday and increase thunderstorm chances thereafter.

SHORT TERM /THROUGH FRIDAY NIGHT/

Issued at 300 AM MDT Thu Jul 23 2026

Abundant moisture continues to stream through the area this morning thanks to an upper level shortwave interacting with monsoon moisture. Heavy rainfall has been fairly isolated so far, but showers with isolated embedded thunder are producing locally moderate heavy rainfall early this morning, which will continue for several more hours. We should see coverage decrease a little bit around sunrise, but some shower activity is expected to continue across the area for most of the next 24 hours. With the shortwave trough axis moving through today, we will enjoy the coolest day of the week today with highs generally in the mid 70s to mid 80s under partly sunny skies. Coverage of showers and thunderstorms will kick up quickly after noon once again today with scattered to numerous storms expected through the evening hours. We are not expecting widespread rainfall across the entire area, but locally heavy thunderstorm rainfall remains possible. Precipitable water will remain fairly steady through the day today, around 1" in the mountains of southern Wyoming, increasing to near 1.75" in portions of the Nebraska panhandle. This remains easily over the 99th percentile of climatology for most of the area, and potentially pushing climatological maximums. As is typical in these monsoon patterns, instability looks somewhat limited due to unimpressive lapse rates. The organized severe weather threat looks limited today, but gusty outflow winds exceeding 60 mph can hardly ever be ruled out when thunderstorms are in the forecast in our area. The primary concern remains frequent lightning and locally heavy rainfall / flash flooding. While confidence in widespread flash flooding is pretty low at this time, localized flash flooding certainly remains possible. It is difficult to pinpoint an area of maximum concern today, and it will depend on where thunderstorms manage to develop. Therefore, the Flash Flood Watch remains in effect until midnight tonight, but it is worth emphasizing again that this is for localized heavy thunderstorm rainfall, not widespread steady excessive rainfall. Drier air above 500-mb will move in from the west this evening as the monsoon surge comes to its conclusion. Expect shower and thunderstorm activity to wind down quickly after midnight.

The ridge aloft will amplify across the Rockies on Friday into the weekend, leading to another round of heat. Temperatures will climb considerably on Friday, reaching the mid to upper 80s around Laramie and Rawlins, and upper 80s to 90s east of I-25. Temperatures aloft will surge much faster than in the boundary layer. 500-mb temperatures are expected to be near or even exceeding climatological maximums over much of the area Friday afternoon despite 700-mb temperatures "only" around the 90th percentile. This will result in a robust capping inversion around 550-mb per forecast soundings, which will put a strong cap on thunderstorm activity. Overall, expect little to no afternoon showers and thunderstorms Friday.

LONG TERM /SATURDAY THROUGH WEDNESDAY/

Issued at 300 AM MDT Thu Jul 23 2026

Another round of heat will be the main story this weekend into early next week. 700-mb temperatures are expected to climb to around +17C to +20C across the area by Saturday afternoon and remain there through Monday. This values are around the climatological 99th percentile (and this is the hottest time of the year too). Laramie and Rawlins can expected highs near 90 degrees each of these days Saturday through Monday, while those to the east of I-25 will be in the mid 90s to mid 100s. Sunday looks like the hottest day of the period, with daily record highs explicitly forecast at Alliance, Chadron, and Sidney. Tied records are in the forecast for Cheyenne and Laramie. While widespread thunderstorm activity is not expected over the weekend, we will lose the upper level inversion as the boundary layer warms and 500-mb temperatures drop ever so slightly. We should reach convective temperatures and produce a few isolated high-based showers and thunderstorms both Saturday and Sunday afternoons. Gusty winds will be the primary concern with deep inverted-v boundary layers.

Another surge in monsoon moisture is expected to begin Monday as the powerful upper level ridge shifts slightly to the east. NAEFS mean precipitable water values exceed the climatological 90th percentile again by Monday and remain there through at least Wednesday. Therefore, expect scattered afternoon and evening showers and thunderstorms to increase in coverage these days. Monday will bring near record heat once again, but expect temperatures to moderate a little closer to seasonal averages after that as moisture improves.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

Issued at 533 AM MDT Thu Jul 23 2026

Overnight showers are beginning to clear out of the area, but expect some in the vicinity of SNY, AIA, and CDR for the next few hours. In addition, fog and low CIGs may impact flight conditions at these terminals for the next few hours, though confidence is quite low in timing and extent of this region of low clouds.

Expect limited shower coverage through the morning hours, which will increase again afternoon. Thunder will also be more likely this afternoon through the evening. Confidence is low in the exact timing and location of PM thunderstorms, so the latest TAF update retains the PROB30 groups at most terminals. Today's thunderstorms will be capable of producing frequent lightning, torrential rainfall, and gusty winds. Isolated small hail is also possible. Expect showers and storms to come to an end between 03z and 06z with skies trending clear into Friday morning.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Flood Watch through this evening for WYZ101>119. NE...Flood Watch through this evening for NEZ002-003-019>021-054- 055-095-096.