textproduct: Cheyenne

KEY MESSAGES

-Red Flag Warning through 9 PM tonight for much of southeast Wyoming for gusty winds, low humidities and dry lightning from some storms.

-Marginal risk of severe thunderstorms east of a Lusk to Cheyenne line Wednesday afternoon and evening, with a slight risk of severe thunderstorms for much of the Nebraska Panhandle.

-Cooler with widespread showers and scattered thunderstorms for Thursday, producing beneficial rainfall.

-Decent chances for afternoon and evening showers and thunderstorms Friday through the weekend, with high temperatures only in the upper 70s to mid 80s, providing a respite from the hot weather.

SHORT TERM /THROUGH WEDNESDAY NIGHT/

Issued at 103 PM MDT Tue Aug 11 2026

Tonight...Challenges include ongoing Red Flag Warning along with shower and thunderstorm coverage and gusty winds from convection.

The ongoing Red Flag Warning is looking decent, especially across Converse County where winds and relative humidities are exceeding Red Flag Warning criteria. The main threats from isolated to scattered thunderstorms from the Snowy Range across the Laramie Valley to the southern Panhandle will be high based thunderstorms producing dry lightning and therefore necessitating the need for the Red Flag Warning continuing until 9 PM.

As far as shower and thunderstorm coverage, models including the HRRR and NAM suggest scattered showers and isolated thunderstorms through early evening from Saratoga, to Laramie, to Cheyenne, to Kimball and to Sidney and nearby locations. Due to the dry low levels and steep dry adiabatic lapse rates, most of the rain from storms will evaporate or fall as virga, and produce brief, erratic and gusty winds in the stronger storms up to 55 mph.

There is a minimal threat for an isolated strong to severe thunderstorm up in the northern Nebraska Panhandle through early evening along a surface convergence boundary and decent 850/700 mb theta-e ridge axis. CAPE and shear look adequate for a few storms to become strong to severe, most likely in Dawes County Nebraska, our infamous Dawes County Clipper.

Wednesday and Wednesday night...The Storm Prediction Center in Norman, Oklahoma paints a marginal risk of severe thunderstorms in the afternoon and evening roughly east of a Lusk to Cheyenne line, with a slight risk of severe thunderstorms for most of the Nebraska Panhandle. This seems quite plausible considering the following factors. A pronounced shortwave trough aloft, markedly noticed in the 700 mb flow near 10,000 feet MSL, will pass across our counties near peak heating and during the early evening hours, while an impressive low level convergence axis develops along the Wyoming and Nebraska state line in the afternoon. Low level moisture will be plentiful across western Nebraska with dewpoints in the 60s with a healthy 850/700 mb theta-e ridge axis oriented north to south across western Nebraska.

CAPE values from 1000 to 2500 J/kg and bulk shear values near 35 knots for the Nebraska Panhandle will be sufficient for scattered thunderstorms, some severe in the afternoon and evening, and have painted large hail and damaging winds in the slight risk area in the grids, with small hail and gusty winds for the marginal risk area east of a Lusk to Cheyenne line.

LONG TERM /THURSDAY THROUGH MONDAY/

Issued at 103 PM MDT Tue Aug 11 2026

Thursday evening starts off this long term period with monsoonal moisture moving in, and a shortwave moving through the area. With precipitable water values in the 1-1.5 range, RH values 60-90%, and the shortwave, its safe to say our area will be getting some much needed moisture. This moisture sticks around through Monday, bringing daily afternoon chances of precipitation. This precipitation looks to mainly be showers, but an isolated thunderstorm cannot be ruled out especially near the NE panhandle with CAPE values near 1000J/kg. Winds do not appear to be out of the ordinary, staying below 15 knots most of the time. Temperatures cool off as a cold front moves over the area Thursday. 700mb temperatures stay near 12C during the daytime Thursday-Sunday, with nighttime temperatures getting near 10C. This means temperatures will cool off nearly 20F from what we have been experiencing. Typically our area has daytime temperatures near 83F this time of year. This is a welcomed break from our hot temperatures the last few weeks. With all of this monsoonal moisture coming in, fire weather is not a concern through this long term period.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 1134 AM MDT Tue Aug 11 2026

All terminals except KBFF and KAIA can expect to see showers/thunderstorms this afternoon. These storms will bring little precipitation and gusty winds. The WY terminals can expect winds mainly from the west to northwest this afternoon. The NE terminals is more variable, but the afternoon looks to have a west/northwest push. Once the showers/storms move out of the area, winds calm down to around 12 knots or less for most terminals. VFR conditions are expected through this TAF period however, visibility may drop below 3sm under the strongest storms but most of the time should stay around 5 to 6sm.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Red Flag Warning until 9 PM MDT this evening for WYZ417>430. NE...None.