textproduct: Cheyenne

KEY MESSAGES

- Hot, dry and breezy conditions expected through the end of the week.

- Mostly dry weather will continue for Friday and Saturday, with daily increasing chances for afternoon and evening showers and thunderstorms for Sunday through Wednesday due to monsoonal moisture spreading eastward across southeast Wyoming and western Nebraska.

- Maximum temperatures will remain hot Friday and Saturday, with a decent cooling trend in high temperatures for Sunday into midweek due to increasing cloud cover and increasing shower and thunderstorm coverage.

SHORT TERM /THROUGH THURSDAY NIGHT/

Issued at 140 PM MDT Wed Jul 15 2026

Short term remains much of the same as a ridge of high pressure aloft continues to sit over the region with a very weak surface front associated with a trough moving into the CWA through Thursday night. As this weak boundary makes its way into our area, some high resolution guidance is trying to form some initiation off of it and bring a chance for thunderstorms, but with incredibly dry surface profiles producing inverted V soundings and daytime dewpoints in the 40's, more than likely if anything can form off of this boundary it's going to be high based with virga struggling to reach the surface as rain, and threatening only dry lightning or a gusty outflow. But aside from a couple of the high resolution models, struggling to see much in the way of meaningful or even weak precipitation being possible, and so have left the NBM as is with no additions to precipitation chances at this time. Otherwise this front isn't going to offer much in the way of relief as temperatures are nearly identical to today with highs in the upper 80's to upper 90's, with perhaps a degree or two shaved off west of the I-25 corridor, but otherwise relief not in sight from this summer heatwave. As for headlines, pressure gradients will weaken enough that winds should lessen into Thursday and RH values will at least rise into the upper teens to low 20's, enough that Red Flag conditions will be allowed to expire today. Heat advisory for Thursday also feels unnecessary with only a site or two expected to reach triple digits, and so will let those expire this evening, but a new heat advisory may be needed for the weekend when temperatures rise once again.

LONG TERM /FRIDAY THROUGH WEDNESDAY/

Issued at 140 PM MDT Wed Jul 15 2026

Friday...Ridging aloft remains entrenched over our region, while there should be a slight increase in mid level monsoonal moisture, though likely not enough mid level moisture to initiate thunderstorm development, because of the warm mid level 700 mb temperatures from 15 to 20 Celsius, producing enough CIN, Convective Inhibition, to keep POPS near nil. Near perfect day weatherwise for outdoor weather activities, with maximum temperatures in the mid to upper 80s west of I-25, and 90s to near 100 degrees east of I-25. Please be sure to drink plenty of water and stay hydrated when outdoors for any significant length of time.

Saturday...With the ridge aloft remaining parked over Wyoming, and warm mid level temperatures producing enough CIN, convective inhibition, this will limit areal coverage to isolated to widely scattered showers and thunderstorms over our Snowy and Sierra Madre Ranges in the afternoon, and over much of Carbon County including Rawlins in the evening...otherwise dry.

Sunday...GFS progs the ridge aloft over the northern Rockies to be flattened somewhat with zonal flow developing over Montana and northern Wyoming. A weak perturbation, or shortwave trough aloft, will move across our counties in the afternoon and evening, with monsoonal moisture advecting into our western counties west of I-25, where we anticipate scattered showers and thunderstorms to develop in the afternoon west of I-25, with the greatest areal coverage over the Snowy, Sierra Madre and northern Laramie Ranges. So, more beneficial rain will occur. Monsoonal moisture is progged to advect further eastward in the evening, spawning isolated to scattered showers and thunderstorms for our counties east of I-25, with lesser coverage over the Nebraska Panhandle.

Monday...Monsoonal moisture at low and mid levels increases further, aiding in another increase in late day shower and thunderstorm coverage, and beneficial rains, with coverage increasing to scattered, 30 to 60 percent POPS, with the greatest coverage over and near our mountain zones.

Tuesday and Wednesday...The zonal flow aloft continues with abundant monsoonal moisture remaining over our CWA, County Warning Area, helping to produce scattered to numerous showers and scattered thunderstorms in the afternoons and evenings with more beneficial rainfall, again with the highest areal coverage over our Snowy, Sierra Madre and Laramie Ranges.

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 545 PM MDT Wed Jul 15 2026

Upper level high pressure is expected to slightly weaken before rebuilding for the weekend. Expect increasing clouds and some shower and thunderstorm activity to return to Carbon and Albany counties, but coverage is uncertain at this time.

HAZARDS/WEATHER TRENDS: VFR conditions expected with southeast winds continuing over the next 24 hours. Gusty southeast winds will continue tonight for KCDR and maybe KAIA as the low level jet restrengthens. Surface pressure gradient doesn't look quite as strong for Thursday, so kept gusts generally below 20 to 25 knots after 17z Thursday.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Red Flag Warning until 8 PM MDT this evening for WYZ417>420- 423-427-430>433. Heat Advisory until midnight MDT tonight for WYZ101-102-107- 108-118-119. NE...Red Flag Warning until 8 PM MDT this evening for NEZ434>437. Heat Advisory until midnight MDT tonight for NEZ002-003- 019>021-054-055-095-096.