textproduct: Cheyenne

KEY MESSAGES

- Slight Risk of severe thunderstorms this afternoon and Thursday with heavy rainfall, hail, and strong gusty winds possible.

- A ridge builds late in the long term, drying the area out and developing Red Flag and potential heat advisory conditions through next week.

SHORT TERM /THROUGH THURSDAY NIGHT/

Issued at 405 AM MDT Wed Jul 8 2026

A small plume of showers is slowly weakening as it moves eastward along I-80 this morning. Only a trace to couple hundredths is expected from this shower, so no beneficial rain is expected unfortunately. Another shortwave is expected to push across the region this afternoon. Hi-res models have initiation starting around 20z but the majority of the forcing won't arrive until about 00z in the form of lobes of strong vorticity. RAP has 3CAPE around 5-600 joules with MUCAPE around 1100 joules. The models maintain a rather straight hodograph for the mid-levels while the sounding indicates a rather dry lower level. This environment best suits gusty winds and large sized hail. With 0-6 Bulk shear around 50-60 kts in the Panhandle there's enough shear to separate the storms updraft and downdraft for sustained intensity. Given the setup of a shortwave with accompanying vortmaxes the HRRR and NAM-nest are probably the most reliable given their history with this setup. Both models have thunderstorms occurring in two phases with the weaker set of thunderstorms happening first. The two models diverge in the second phase as the HRRR has all the stronger storms developing north of our forecast area then dropping south into the Panhandle from South Dakota for a classic Dawes county clipper scenario. THe Nam-nest has all the forcing staying over our area from 00z to 06z and the Panhandle getting all the storms. So it will be interesting to see where the forcing sets up for our thunderstorms to utilize. SPC has the far-eastern portion of Wyoming and the all of the Panhandle in a slight risk for this afternoon with hail and high winds as the main threat. The models have the storms ending between 06z to 08z however the intermountain west looks to lose the shear closer to 04z so our severe potential window looks to be from 22z to 04z or 2pm to 10pm tomorrow. Thursday looks to be a wash rinse repeat of today. The same ingredients are present however the bulk shear looks to be a tiny bit weaker Thursday afternoon. However, the Panhandle does receive more a little bit more moisture at the surface Thursday compared to today. This means the storms will have a more energy to utilize but with weaker shear. Thunderstorms look to initiate around 21z again and last until 04z. Given the weaker shear these thunderstorms are more likely to be pulsy in nature with decent microburst potential but also able to produce some severe hail when they pulse up. Given the history with this section of the Intermountain west, Severe winds will be possible with collapsing cores and in the stratiform region of the storms with accumulating hail with a couple quarters thrown in there.

LONG TERM /FRIDAY THROUGH TUESDAY/

Issued at 405 AM MDT Wed Jul 8 2026

Friday, the upper level pattern starts to change as an upper level ridge starts to build around the Intermountain West and expand into the Central plains. The global models have come into an agreement about the ridge becoming pretty stout and will dry us out possible through the start of the next work week. NAEFS has most of Wyoming and the Panhandle in the 90th and above percentile through the end of next week. It will be HOT and Dry in the long term for a possible extended Red Flag warning for our entire CWA due to the already dry fuels and low RH's. However, the important wind component may not show up while under this broad ridge until Sunday as a shortwave looks to give us some breezy conditions worthy of a Red Flag. Temperatures will rise into the 80's and 90's this weekend with potential 90's and 100's by the start of the next work week. Staying cool will be a must and if you have to work outside may sure to take plenty of breaks and snack between meals so your body can retain some electrolytes that will be lost from sweating.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 1128 AM MDT Wed Jul 8 2026

A relatively active day for thunderstorm development is expected this afternoon and evening, as the Storm Prediction Center in Norman, Oklahoma has a slight risk for severe thunderstorms this afternoon and evening, to the east of a Lusk to Cheyenne line, including far southeast Wyoming and the Nebraska Panhandle. A marginal risk of severe thunderstorms for this afternoon exists elsewhere to the west of a Lusk to Cheyenne line.

Synoptically, a negatively tilted shortwave trough aloft will move into western Nebraska this evening, while a low level convergence axis develops along the Interstate 25 corridor, then storms will develop and strengthen as they develop and propagate across far southeast Wyoming, and especially the Nebraska Panhandle, where scattered thunderstorms may conglomerate and develop into a Mesoscale Convective Complex, or MCC, somewhere over the northern or central Nebraska Panhandle this evening, thunderstorms will likely end across the Nebraska Panhandle in the 03Z timeframe.

Wyoming TAFS...Using the 16Z HRRR, which has consistently been fairly accurate with respect to timing, high confidence, and expect thunderstorm initiation between 18Z and 20Z from a Douglas to Laramie line, with storms strengthening along the I-25 corridor near 22Z, and mostly moving into western Nebraska around 00Z to 02Z.

Expect TEMPO for thunderstorms at Rawlins and Laramie for much of the afternoon and into the early evening hours, and some storms will produce low level turbulence, strong downdrafts, as well as gusty and erratic winds up to 45 knots, along with brief MVFR visibility restrictions. VFR prevails however, with clouds clearing out late this evening and overnight. As is typical, expect gusty gradient and mix down winds until sunset.

At Cheyenne, best chance for thunderstorms, and high confidence, according to the likely accurate 16Z run of the HRRR, will be from 20Z to 02Z, with storm initiation around 20Z, and storms increasing in coverage and intensity from 22Z to 01Z. Some storms will produce low level turbulence, strong downdrafts, as well as gusty and erratic winds up near 50 knots, along with brief MVFR visibility restrictions. VFR prevails however, with clouds clearing out late this evening and overnight. As is typical, expect gusty gradient and mix down winds until sunset.

Nebraska TAFS...High confidence in the 16Z HRRR run, which has consistently shown thunderstorms developing and/or propagating along the Wyoming and Nebraska state line around 23Z, and crossing the Panhandle during the 00Z to 03Z time frame, with clusters of thunderstorms and a possible MCC, Mesoscale Convective Complex, forming this evening, somewhere over the northern or central Nebraska Panhandle and propagating southeastward. The strongest storms will be capable of producing one inch diameter hail or larger, wind gusts in excess of 60 mph and locally heavy rainfall, along with low level turbulence, and strong downdrafts. Brief MVFR will be likely during the thunderstorms this evening, with skies clearing out late this evening and late tonight. As is typical, expect gusty gradient winds and mix down winds until sunset.

CYS WATCHES/WARNINGS/ADVISORIES

WY...None. NE...None.