textproduct: Cheyenne

KEY MESSAGES

- Westerly downslope winds will keep majority of the forecast area dry today with widely scattered showers and thunderstorms in the northern portion of Converse and Niobrara county through late this afternoon.

- Monday & Tuesday brings another chance for strong to severe thunderstorms in the afternoon and evening. There is a slight risk (level 2 of 5) across the eastern high plains on Monday. Large hail, severe wind, and an isolated tornado possible.

- A warming and slight drying trend appears likely after Wednesday with temperatures climbing into the 80s by later in the week and during next weekend.

SHORT TERM /THROUGH TUESDAY/

Issued at 150 PM MDT Sun May 31 2026

Quieter weather observed today across much of the area with seasonable temperatures in the mid 60s to mid 70s. Current KCYS radar loop shows some widely scattered thunderstorms over east central Wyoming, northeast of I-25. Expect this activity to remain sub-severe as it moves eastward through the afternoon and evening hours. Further south, dry westerly winds have continued with High Wind Warnings in effect for Arlington/Elk Mountain and Bordeaux, along I-80 and I-25 respectively. Peak gust so far today has been 65 MPH between Elk Mountain and Arlington. Will let this Warning go for a few more hours before expiring it at 300 PM. Winds have already shown sign of diminishing across these areas early this afternoon. Otherwise, with a dry airmass in place and clearing skies, expected chilly lows in the upper 30s to mid 40s across most of the area by early Monday morning.

For Monday, showers and thunderstorms should return to the high plains as surface winds shift into the south and southeast. Further west, another broad upper level trough will brush the northern Great Basin region and move into Wyoming later in the day. Depending on the timing, there is another good chance for strong to severe thunderstorms across far southeast Wyoming and most of the western Nebraska Panhandle mid to late afternoon and early evening hours. Guidance shows the moisture return fairly slow across most of the high plains with dewpoints gradually climbing through the afternoon. All other parameters look good with 0-6km shear around 40 knots and some 0-2 km low level shear. Will monitor to see how good the moisture return off the Great Plains is heading into tomorrow with models showing large discrepancies in moisture (and CAPE). SPC has an area of Slight Risk for severe thunderstorms southeast of a line from Cheyenne to Chadron Nebraska, and a Marginal Risk towards the I- 25 corridor. With deeper low level moisture arriving by the evening hours with south to southeast winds, added some fog to the I-80 corridor through early Tuesday morning.

A quick look into Tuesday, possibly a better convective environment setting up for the day. Models show a subtle shortwave lifting northeast across the area through the day with ample low level moisture and dewpoints in the upper 40s to mid 50s possible. Typical convergence axis sets up along the Laramie Range and should provide the forcing needed to break any cap inversion that sets up that morning. Will need to monitor Tuesday afternoon closely with deep shear and SBCAPE as high as 2000 j/kg. Relatively low LCL's and 0-1 km EHI's between 1 to 2 are also concerning along and east of the I- 25 corridor. SPC currently has a large Marginal Risk, but this may become at least a Slight Risk over the next 24 hours. Temperatures will be pleasant as we enter June with highs in the mid 70s to low 80s. Slightly cooler along the south facing ridges due to southerly winds (Pine Ridge, Cheyenne Ridge).

LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/

Issued at 150 PM MDT Sun May 31 2026

We remain under SW flow aloft upstream of a high amplitude positively-tilted ridge centered over Ontario and the Great Lakes region, resulting in mostly dry and above-average temperatures heading into the second half of the week. Thanks to trajectories stemming from the Gulf of Mexico, PWAT over SE Wyoming and W Nebraska will be in the 80th-90th percentile relative to climatology. This will allow for daily chances of showers and thunderstorms despite the absence of any large-scale forcing for ascent. Despite anomalously high PWAT, long range ensemble forecast soundings continue to show large dewpoint depressions at the surface and inverted-V profiles, so any showers or storms will likely produce far more wind than any beneficial moisture. The threat for any severe weather looks to remain low towards the end of the week as deep-layer shear is weak due to the lack of mid and upper level flow. Going into the weekend, high temperatures are expected to push 80 degrees west of the I-25 corridor, with even a few 90s for our Nebraska counties as we remain under longwave ridging through the end of the long term period.

AVIATION /18Z TAFS THROUGH 18Z MONDAY/

Issued at 1105 AM MDT Sun May 31 2026

VFR will prevail for all terminals throughout the TAF period. Expect gusty westerly winds up to 40 knots for the Wyoming terminals until 00Z, with the Nebraska terminals seeing gusts up to 30 knots. Winds will relax into the evening hours down to 10-15 knots before becoming variable around sunrise. Expect mostly clear skies with a few high clouds aoa 20k ft with our typical diurnal cumulus dissipating quickly after sunset.

CYS WATCHES/WARNINGS/ADVISORIES

WY...High Wind Warning until 3 PM MDT this afternoon for WYZ106-110. NE...None.