textproduct: Cheyenne

KEY MESSAGES

- A Marginal Risk for strong to severe thunderstorms expected Thursday. Strong winds and heavy rainfall are the primary concerns, though large hail is still possible.

- A Flash Flood Watch has been issued for the South Fork burn scar area due to the potential for multiple rounds of thunderstorms with heavy rainfall in the vicinity.

- Warming temperatures, falling humidity, and increasing winds will increase fire weather concerns this weekend into early next week.

SHORT TERM /THROUGH SATURDAY/

Issued at 245 AM MDT Thu Jun 25 2026

Current KCYS radar loop across the region shows scattered to numerous showers and embedded thunderstorms across most of southeast Wyoming and the central and northern Nebraska Panhandle at this hour. Nocturnal convection is being driven primarily by a broad upper level trough moving eastward across Wyoming and Colorado this morning, in addition to some elevated CAPE in the midlevels. If anything, expect shower activity to increase in coverage as the base of this trough moving over the I-25 corridor between early this morning and noon today. In between shower activity, kept patchy fog in the forecast along and east of I-25 with several locations already showing 1/2 to 2 miles visibility. With the slower movement of the trough and low clouds and/or fog remaining over the area through most of the morning, this will play a large part in convection potential this afternoon.

Cooler temperatures expected today due to cloud cover and the slower movement of the upper level trough axis. This will also limit instability in the boundary layer and in the midlevels. The Slight Risk has been lowered to a Marginal Risk for strong to severe thunderstorms today through this evening. Primary threat still appears to be strong gusty winds (can't totally rule out some marginally severe hail as well), but convective parameters don't look favorable for widespread strong winds with MLCAPE struggling to climb above 800 j/kg for much of the day due to persistent cloud cover. All models show the convection growing upscale with squall lines and possibly bow echoes forming this afternoon and rapidly moving southeast across the plains into this evening. Should be a late show for this activity with high resolution guidance showing a line of strong storms moving across far eastern Wyoming and western Nebraska between 5 to 9 PM. Looks like mainly heavy rain, strong (brief) gusty winds, and frequent lightning will be the primary threats into this evening. Flash flooding looks less likely today considering yesterday's conditions were far more favorable but storms failed to produce. High temperatures today will struggle to reach 70 degrees for most of the area.

All models show a warming and drying trend beginning on Friday as the upper level flow backs into the southwest ahead of an elongated upper level trough across the Pacific coast. 700mb temperatures will respond and climb above 13c. Southerly winds will keep temperatures in the low to mid 80s, which is still slightly above average for this time of the year. Models show an embedded shortwave moving east across the area Friday afternoon, which will likely trigger another round of thunderstorms. However, with the drier airmass beginning to push into the region, expect coverage to be lower compared to the last several days. The most favorable location for strong to severe thunderstorms will likely be east of I-25 into western Nebraska, with thunderstorms pushing out of the area by the early evening hours (6 to 8 pm).

Dry weather returns on Saturday as southeast Wyoming and western Nebraska will have a break from the recent thunderstorm activity. All models indicate 700 mb temperatures climbing between 14c to 18c, which translates to surface high temperatures in the mid 80s to mid 90s, warmest for elevations below 4500 feet. Other than increasing fire weather concerns, quieter weather is expected this weekend.

LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/

Issued at 230 PM MDT Wed Jun 24 2026

Sunday through Wednesday...A broad trough aloft develops across the northern and central Rockies, with dry southwest flow aloft, leading to only isolated to widely scattered thunderstorms at most in the afternoons and evenings. A progressive shortwave trough aloft is progged to move to the western Dakotas on Monday, with its associated cold front bringing a cooler airmass behind the likely moisture starved cold front. The dry southwest flow aloft continues for Tuesday and Wednesday with a slow warming trend.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

Issued at 550 AM MDT Thu Jun 25 2026

Low confidence Aviation forecast for most of the area due to uncertain coverage of heavy showers and off/on fog this morning. Expect numerous rain showers to continue as an upper level trough axis moves eastward into western Nebraska this morning. With some clearing skies this afternoon, another line of strong thunderstorms is expected to push across all terminals late in the afternoon and evening hours.

HAZARDS/WEATHER TRENDS: Complicated TAFs across the area with several hazards and rapidly changing conditions expected. Upper level trough will move across the area this morning, resulting in an area of moderate to heavy rainfall and embedded thunderstorms 12z to 19z. High resolution model guidance remains aggressive with IFR to LIFR conditions, but conditions have not verified well so far. Tweaked TAF for the western Nebraska panhandle and trended towards low-end MVFR to high-end IFR (700 ft to 1500 ft CIGS and occasional drops in VIS). KSNY will be the only exception to this since they have stayed close to 500 feet CIGS this morning. VFR to MVFR VIS possible at times for the southeast Wyoming terminals with any heavier showers.

For this afternoon, expected a break in the precipitation. A line of strong thunderstorms is then expected to from and quickly move southeast...impacting KRWL, KLAR, and KCYS between 22z today and 02z Friday with IFR conditions and strong gusty winds.

CYS WATCHES/WARNINGS/ADVISORIES

WY...None. NE...Flash Flood Watch through this evening for NEZ002-095.