textproduct: Cheyenne

KEY MESSAGES

- Red Flag Warnings are in effect until 8 PM tonight for gusty winds and low humidity for much of Southeast Wyoming.

- Red Flag Warnings are in effect from 11 AM to 8 PM Friday for portions of southeast Wyoming west of Interstate 25, including much of Carbon and Albany Counties for gusty winds and low humidity.

- Hot temperatures return Friday through Sunday with slightly cooler temperatures Monday through next Wednesday.

SHORT TERM /THROUGH FRIDAY NIGHT/

Issued at 332 PM MDT Thu Aug 6 2026

Tonight...Main challenges tonight will be the possibility of isolated to widely scattered thunderstorms through early evening across our far eastern counties roughly east of a line from Chadron to Sidney. The Storm Prediction Center in Norman, Oklahoma has a small sliver of marginal risk for severe thunderstorms through this evening, which seems quite plausible based on the positioning of the north to south oriented 850/700 mb theta-e ridge axis and some decent low level convergence. Satellite imagery on the visible range shows little if any cumulus development in our far eastern counties. Looking at SPC mesoanalysis, there is adequate CAPE and minimal CIN, thus feel it would be prudent to include a small chance of thunderstorms through early evening for the aforementioned area.

The current Red Flag Warning is on track through 8 PM and winds have been overperforming per observations and thus will continue the product as is.

The low relative humidities will allow for another pleasant sleeping night for having the windows open with minima in the 40s over the mountains and 50s at lower elevations.

One interesting feature is that a weak surface trough or weak cold front will nudge southward into our northern and eastern counties late tonight with only a wind direction switch and no other sensible weather effects.

Friday...Primary challenge again will be likely Red Flag Conditions for much of Carbon and Albany Counties. No doubt the humidities will be bone dry once again, and with the projected 700 mb winds, near 10,000 feet MSL, mixing down to the surface and gradient winds, coordination amongst our daytime forecast team here at team Cheyenne led us to issue a Red Flag Warning from 11 AM to 8 PM for much of Carbon and Albany Counties.

While northwest flow aloft continues, a cold frontal boundary will lie across our eastern third of counties, providing some minor cooling compared to today for the Nebraska Panhandle, while on the warm side of the front further to the west, we anticipate a slow warming trend. Fortunately, relative humidities will be quite low, making the apparent temperatures or heat index numbers quite reasonable despite maximum temperatures in the 90s.

Friday night...Another quiescent overnight under northwest flow aloft and with the airmass moderating, minimum temperatures will not be as cool as tonight, with lows in the mid 50s to lower 60s.

LONG TERM /SATURDAY THROUGH THURSDAY/

Issued at 332 PM MDT Thu Aug 6 2026

The highlight of the long term forecast period will be a slow transition back out of the hot and dry weather pattern back into more seasonal temperatures and occasional rainfall chances. Another weekend heat wave is on tap for Saturday and Sunday. For the fifth consecutive weekend, a broad upper level ridge aloft will support above average temperatures across our area. 700-mb temperatures around +16C to +20C are not quite as extreme as the last two weekend heatwaves, but still sufficiently high for continued near record heat. Expect highs both days in the lower 90s for Laramie, Rawlins, and Saratoga, and then mid 90s to lower 100s over the High Plains. Currently, record highs are only forecast at Laramie and Cheyenne, but all locations will be within 1 to 3 degrees of daily record highs. This heat wave does not look as likely to challenge all-time or monthly records, but we will certainly be hot. The chance for storms looks very limited on Saturday, but we will finally start to see precipitable water return to near average on Sunday. The upper level ridge will start to weaken and slowly nudge eastward, allowing monsoon moisture to fill to the north once again. We may see a few showers or thunderstorms creeping into our southern mountains by Sunday, but this will probably still be quite limited. While the probability for rainfall will be low, forecast soundings favorable for dry microbursts, so gusty winds may be the initial concern as moisture tries to return to the area.

Ensembles show precipitable water continuing to gradually improve through the week ahead as monsoon moisture expands to the north once again. Coverage will probably be fairly limited early in the week, but look for higher chances for precipitation towards the middle to later part of the work week. While we are still a ways out for details, this doesn't really look like a pure monsoon pattern. A few intrusions of shortwave troughs to our north may keep vertical wind shear high enough to get a few strong to severe thunderstorms. As moisture mixes through the boundary layer, we should also ease the fire weather concerns as humidity climbs.

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/

Issued at 531 PM MDT Thu Aug 6 2026

VFR conditions are expected for the forecast period. While a rogue shower/storm cannot be ruled out around AIA or SNY, the probability is too low to add to the TAF. Otherwise, wind gusts should ease in the next few hours. The direction may become variable overnight at times. A weak boundary pushing through the plains will turn winds to the northeast, and then southeast during the day Friday. Look for gusty west to northwest winds again at LAR and RWL.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Red Flag Warning until 8 PM MDT this evening for WYZ417>430. Red Flag Warning from 11 AM to 8 PM MDT Friday for WYZ420>422- 425>427. NE...None.