textproduct: Cheyenne

KEY MESSAGES

- Temperatures warm a few degrees on Friday with isolated to scattered thunderstorms expected alongside a marginal risk of severe weather and a slight risk of excessive rainfall.

- Unsettled weather continues through at least Sunday, bringing cooler than average temperatures and daily chances for showers and thunderstorms.

- Isolated strong to severe storms and localized flash flooding will remain possible through Sunday.

- Drier weather and temperatures close to seasonal averages will return early next week.

SHORT TERM /THROUGH SATURDAY NIGHT/

Issued at 230 AM MDT Fri Aug 14 2026

Scattered showers and weakening thunderstorms are ongoing across the CWA this morning, leftovers from yesterday's activity. These showers should continue to weaken through sunrise, with precipitation and cloud cover then expected to begin clearing out through the afternoon in response to drier westerly flow at the surface, allowing for a bit more daytime heating than yesterday. Temperatures will rise back up in response to this, with locations west of the Laramie Range generally still under enough cloud cover that highs will only max in the upper 70's for the day. East of the Laramie Range, we'll see the return of the 80's, with a few spots in the Nebraska Panhandle possibly even achieving the very low 90's again. As for our thunderstorm chances, while not as widespread and heavy as the past couple of days, we should see another round of activity form during the early afternoon and continue into the evening, the strongest of which should fire off of the high terrain and move across the high plains into the evening. There will be some limitations to the strength of this though, with the best instability along the border of and into Colorado or further east into Nebraska. But some guidance still produces decent low to mid level lapse rates in the 8-9 C/km range, and bulk 0-6 km shear has pockets in the 30-40 knot range, so a few storms along the I-80 corridor from Cheyenne through the Panhandle could be strong to severe. Also, our PWATs definitely aren't shabby, in the 1.2-1.4 inches range, and a few pockets nearing 1.5 inches are showing up, so any showers and storms could once again produce moderate to heavy rainfall. And with soils now at least moist from multiple rounds of precipitation, it may be easier again for localized flooding to occur.

Saturday we will cool back down by a few degrees into the widespread 70's and low 80's as a modest cold front drops across the region, possibly aided by pockets of cloud cover lingering from Friday's activity. But we are anticipating some fairly decent destabilization on Saturday across the high plains, with more widespread and favorable CAPE in the 1000-2000 J/kg range, steep lapse rates, and more readily available bulk shear. Because of this, a slight risk of severe weather is expected from Cheyenne eastwards and across most of the Nebraska Panhandle, with large hail and damaging wind gusts the most likely hazards. PWAT values will generally mirror Friday's as well, so any strong or training storms could easily produce excessive rainfall once again. Likely scenario for this activity will be storms consolidated into clusters or a linear segment as they start moving out of the CWA towards the early evening, with a few stragglers possible outside of this, but otherwise not the widespread lingering precipitation from the last couple of days.

LONG TERM /SUNDAY THROUGH THURSDAY/

Issued at 1150 AM MDT Thu Aug 13 2026

Saturday...Moist westerly flow aloft and a weak shortwave trough aloft near peak heating will combine with deep atmospheric moisture supply to produce scattered to numerous showers and scattered thunderstorms in the afternoon and evening, with the greatest areal coverage east of Interstate 25. Aiding in the lift will be low level southeast winds adding the mechanical lift in addition to diurnal heating. PWAT, Precipitable water values look decent for beneficial rainfall. 700 mb temperatures yield highs in the 70s to lower 80s.

Sunday...Ridging becomes a bit more pronounced over Wyoming, producing warmer temperatures aloft which will tend to limit areal coverage of showers and thunderstorms, compared to Saturday. Nevertheless though, the monsoonal moisture will stretch from central Colorado through far eastern Wyoming and western Nebraska, where scattered to numerous showers and thunderstorms will occur in the afternoon and evening. Slightly warmer, but comfortable, temperatures for this time in August.

Monday...A drier pattern ensues and is on tap as the flow aloft turns west northwest and the precipitable water values decrease, due to drying at low and mid levels and downslope southwest winds near the surface. Thus, a much drier day when compared to the weekend. A warming trend begins with more sunshine and warmer mid level temperatures.

Tuesday...Brisk westerly flow aloft prevails, and with a decent amount of low and mid level moisture availability, expect isolated to widely scattered late day showers and thunderstorms, mainly east of Interstate 25 and the Laramie Range. Similar maximum temperatures to Monday based on 700 mb temperatures.

Wednesday...The synoptic pattern looks more like September and early autumn with a deep shortwave trough aloft sweeping across western Montana and Idaho, with west southwest flow aloft over our counties. Right now, we have scattered late day showers and thunderstorms in our gridded forecasts, though with a decent increase in precipitable water values, the moist flow aloft, and low level upslope, along with pattern recognition, believe our POPS and convective coverage will likely need to be increased in the next few days.

Thursday...The high amplitude and progressive shortwave trough aloft moves eastward from western Montana, to the Dakotas and western Nebraska by evening, sending a decent Pacific origin cold front across our counties. There may be enough moisture at low and mid levels for isolated to widely scattered convective coverage, though the biggest change will likely be a return to cooler temperatures and windy downslope west winds, which will likely need to be adjusted in the next few days, if model consistency remains for day 7. If you are looking for an early taste of fall weather, this may be your day.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1129 AM MDT Fri Aug 14 2026

Inherited TAFS from our midnight shift Meteorologist were in excellent shape, with only some minimal tweeks needed based on recent observational data and model trends.

Challenges include thunderstorm coverage, intensity, duration and cessation, and secondarily, the likelihood of fog and low cloud development later tonight along and east of the Laramie Range.

Southwest flow aloft prevails, with a shortwave trough aloft, moving up through northeast Colorado, far southeast Wyoming and the southern Nebraska Panhandle later this afternoon and this evening, producing scattered to numerous showers and scattered thunderstorms to the southeast of a Laramie to Chadron line through the evening hours, with far drier conditions elsewhere.

Wyoming TAFS...Using the 12Z NAM and the consistent runs of the HRRR, including the latest HRRR runs, high confidence in the development of scattered to numerous showers and scattered thunderstorms this afternoon and early evening, to the southeast of a Laramie to Torrington line, with enough signals to go with a TEMPO wording for KCYS from 20Z to 24Z, with some storms producing wind gusts up to 48 knots along with some MVFR visibilities and low VFR ceilings. Felt confident enough to include VCTS at Laramie from 20Z to 01Z, and will monitor cumulonimbus development for later updates. Storms look to remain well east of KRWL, thus no mention of thunderstorms there.

Otherwise VFR prevails, with gradient and mix down winds producing gusts to 35 knots at the TAF sites through sunset.

Nebraska TAFS...Using the consistent runs of the HRRR, including the latest HRRR runs, as well as the 12Z NAM, there is high confidence in the development of scattered to numerous showers and scattered thunderstorms this afternoon and this evening, to the east of a line from Laramie to Chadron, with enough signals to go with a TEMPO wording for Scottsbluff and Sidney from 22Z to 02Z and from 23Z to 03z, at Scottsbluff and Sidney, respectively, Some storms at Scottsbluff and Sidney will produce erratic winds and gusts to 45 to 50 knots, with high MVFR and low VFR ceilings and visibilities and even some possible hail.

Locally heavy rain is anticipated across the southern half of the Panhandle later this afternoon and evening from slow moving thunderstorms. Using the HRRR runs, being consistent and all, felt confident enough to include a PROB30 at KAIA from 23Z to 02Z, with MVFR visibilities and low VFR ceilings. No mention of thunderstorms at KCDR.

Otherwise VFR prevails, with mix down winds and gradient winds producing gusts to 25 knots at the sites. Based on expected rainfall and boundary layer progs, and experience with these types of synoptic and mesoscale setups, feel confident enough to include IFR and low MVFR ceilings and visibilities in fog at all sites from roughly 08Z to 15Z.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Flood Watch until 10 PM MDT this evening for WYZ117>119. NE...Flood Watch until 10 PM MDT this evening for NEZ020-021-054- 055.