textproduct: Cheyenne

KEY MESSAGES

- Southwest winds will increase Monday, bringing the potential for critical fire weather conditions over the High Plains and a brief period of high winds in the wind prone areas.

- Elevated fire weather conditions will continue for much of the week ahead.

SHORT TERM /THROUGH TONIGHT/

Issued at 410 AM MDT Mon Jun 29 2026

Active night and early morning over the northern Nebraska Panhandle with several severe thunderstorm over Sioux, Dawes, and Box northern Box Butte Counties late last night up until 2 AM this morning. Confirmed ping pong ball (1.50") to hen egg (2.00") hail over Chadron State Park with unverified reports of larger stones. This activity has since pushed further northeast into South Dakota leaving breeze conditions in its wake. Quiet weather expected through sunrise this morning with increasing clouds to the west...ahead of the potent upper level trough which is expected to produce critical fire weather conditions and possibly strong winds over portions of southeast Wyoming today into this evening.

Based on IR Satellite loop analysis, the base of the potent upper level trough is currently moving across northeast Utah, noted by the distinct comma shape. This feature is expected to quickly push east northeast into Wyoming over the next 6 to 12 hours. Temperatures are already pretty chilly in the Utah mountains with snow likely falling across the peaks. Expect some brief periods of snow for our higher mountains this morning where a dusting up to a half inch of snow accumulation is possible, before quickly melting by this afternoon. As this potent trough lifts northeast, winds are expected to rapidly increase out of the west or northwest. Pretty impressive surface gradient with this system, which will drive the wind gusts up to High Wind criteria for a time today and result in hazardous fire weather conditions (please see Fire Weather Forecast for more information). In-house wind guidance remains cautious with this event, still showing between 35% to 50% probability for high winds between 8 AM and 3 PM. Extended the High Wind Watch to include eastern Platte County with in- house wind guidance taking a noticeable trend upward for Coleman compared to the last few runs. 700mb winds have come down some, but the surface gradient still looks good through noon. The best chance for precipitation with this trough will be across Carbon county near the mountains with low elevation rain showers and maybe a few rumbles of thunder. A very dry airmass will spread across most of the area, which should greatly limit any convection for much of today. Kept POP near zero through most of today and this evening. Not as warm today, with highs in the 60s to mid 70s west of Interstate 25 and across east central Wyoming. Somewhat warmer further southeast with highs in the upper 70s to mid 80s east of Interstate 25. Cool and dry airmass will likely result in some of the high valleys west of I-25 to dip down into the 30s tonight for overnight lows (Laramie Valley, Shirley Basin, and upper North Platte River Valley. With very dry air, don't think frost will be a problem at this time.

LONG TERM /TUESDAY THROUGH SUNDAY/

Issued at 315 PM MDT Sun Jun 28 2026

Tuesday, The upper level low will be lifting off to the east back into the Northern Plains and Canadian providences as a strong ridge over the Midwest and Eastern Seaboard begin to build. By the late evening on Tuesday another weak shortwave will push through the Intermountain West following the parent low moving into Manitoba. There will be a few lobes of vorticity to play with as this wave moves through but it looks as though all the forcing and shower potential may lie only in the Panhandle area. As we progress past Tuesday we become stuck in Southwest flow on the front side of this ridge. The warm, dry, but smokey air from the Desert southwest and the Colorado/Utah fires will be filtering over the area for the remainder of the week. This will limit our rain chances as this dry air removes all the moisture from the surface and lower dewpoints and RH values. The models have a few shortwaves pushing into the region past Tuesday but with no moisture and very limited forcing there isn't much confidence these waves will do anything beside increase our gradient and produce the normal amount of wind through our area. Fire weather will be the biggest concern as our fuels will enter a curing state once again despite our stormy 7 days last week. Winds will be light to marginal so it may be difficult to reach Red Flag criteria for most of our area despite the low RH and curing fuels. There is a trough that is suppose to move through 4th of July weekend that the models are trying to figure out so we may get some rain but the Intermountain West would need a pretty big trough to dig through the four corners region for anything substantial to reach the ground. So we shall see how the models trend but the 4th may just be as dry as the rest of the week as well.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 600 AM MDT Mon Jun 29 2026

Potent storm system will lift northeast across the area today. Very little precipitation expected as the trough axis moves across the area, but winds will quickly increase after 14z this morning and continue into this evening...possibly into the late evening hours.

HAZARDS/WEATHER TRENDS: VFR conditions will prevail today and into tonight. Primary Aviation concern will be windy to very windy conditions across most terminals with KSNY seeing breezy conditions and lower wind gusts compared to the other terminals.

CYS WATCHES/WARNINGS/ADVISORIES

WY...Red Flag Warning from 10 AM this morning to 9 PM MDT this evening for WYZ417>419-430>433. High Wind Watch from 8 AM MDT this morning through this afternoon for WYZ106-107-110-116. NE...Fire Weather Watch from 10 AM MDT this morning through this evening for NEZ434-435. Red Flag Warning from 10 AM this morning to 9 PM MDT this evening for NEZ436-437.