textproduct: Cheyenne

KEY MESSAGES

- Mostly dry and warmer weather will prevail through Wednesday, with thunderstorms possibly returning late this the week.

- Elevated to Near Critical fire weather conditions possible over east central Wyoming and the northern Nebraska Panhandle Monday afternoon.

SHORT TERM /THROUGH TUESDAY NIGHT/

Issued at 240 AM MDT Mon May 11 2026

Quiet weather and warm temperatures expected at the start of the work-week as models continue to show a broad ridge axis aloft moving over the Front Range this morning. 700mb temperatures are forecast to climb above 10c for the whole area, which translates to afternoon high temperatures in the upper 70s to upper 80s. The lowest elevations of western Nebraska may see highs around 90 with dry westerly winds. A few (daily) record high temperatures are expected, mainly over the Nebraska Panhandle in addition to Rawlins. Most other locations should get within a few degrees of the daily record high. Otherwise, Other than some fire weather concerns, pleasant weather is expected today with no changes to the previous forecast.

Models continue to show a shallow cold front moving in from the north late Monday evening and Monday night, resulting in slightly cooler temperatures across the region. Little to no precipitation expected with FROPA with the only moisture advection remaining near the surface. High temperatures will be around 10 to 15 degrees cooler compared to today, but still remaining about 10 degrees above average for mid May. Typically, it would be relatively chilly Tuesday night behind the front with clear skies. However, all models show quick WAA as another ridge axis builds across the Rocky Mountain Region. This will keep low temperatures above average for this time of the year with a very low chance for frost/freezing.

LONG TERM /WEDNESDAY THROUGH SUNDAY/

Issued at 210 PM MDT Sun May 10 2026

An upper level ridge will be centered over the New Mexico and Colorado area with an axis extending north over our area and into Canada. This kind of pattern should favor dry and clear conditions for much of our area. The daytime mixing of the boundary layer will dry out the surface while sinking air from the ridge will heat up the surface. Sampling the GFS model during the afternoon hours of Wednesday is indeed showing these conditions with a nearly 50 degree spread in surface temperatures and dew point temperatures. Maximum temperature will be flirting with daily record highs in some spots with widespread 80s and 90s. Relative humidities will drop into the teens and even single digits for areas in Carbon County. Surface trough development is being depicted in global models just to our north. During the afternoon a corridor of stronger flow to the southwest of this low will collocate with the driest conditions in Carbon and Albany Counties that afternoon. Sustained winds of 30 mph and higher gusts may be possible, though these details are murky being a few days out and depending on the strength of the surface low. Overnight humidity recoveries are expected to be poor for locations west of the Laramie Range. Regardless the pattern does favor elevated fire weather concerns at a minimum and interests should monitor conditions and forecasts for Wednesday and the next following days.

Thursday continues the dry conditions of Wednesday. We do see some monsoonal type moisture funneling in from the Gulf of California and the East Pacific that could be enough to create isolated showers and thunderstorms. PoPs are not high with current forecasts calling for around 20% chances at most. GEFS members give about a 20-40% chance of some areas in the CWA receiving 0.05" of rainfall. Given the fairly dry conditions at the surface most precipitation will evaporate on its way down from cloud level. The ridge axis that had been parked overhead the last few days should start to slide southeast, but dry and warm conditions will continue. Daytime temperatures may climb into the mid to upper 80s for areas east of the Laramie Range, with a slight cooling for the interior mountain regions. Relative humidity values remain low, in the teens, so fire weather concerns continue.

About this time a compact, high amplitude negatively tilted trough will be making its way in from the northwest. Compared to yesterday's guidance, the placement of this trough is trending southward and slower. The surface low that forms Wednesday may be tugged south to met this upper level trough during the day Thursday and Friday. We will likely remain on the dry side of this surface low. With the southward position of the upper level feature our high wind chances have decreased for Thursday, but gusty winds are still likely. Additionally, thunderstorm chances do not seem to have gotten better with this placement given the shut-off of surface moisture under the favorable portions of the jet, though details are still uncertain at this range. There was a slight increase in storm potential from machine learning models for the Nebraska Panhandle for what it is worth. The most likely outcome is a capped environment there.

Friday through the weekend portion of this outlook are appearing cooler following the departure of the upper level system. Another ridging pattern may setup for Friday and Saturday. Dry conditions continue with daytime humidity minimums dropping below 20%.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 550 AM MDT Mon May 11 2026

Upper level ridge axis will build over the region today before a shallow dry cold front moves south across the region late this evening and tonight, with winds shifting into the north.

HAZARDS/WEATHER TRENDS: VFR conditions will continue over the next 24 hours. Occasionally gusty winds up to 25 knots possible over the western Nebraska terminals, with frequent gusts of ~30 knots for the southeast Wyoming terminals this afternoon. Winds will shift into the north behind the cold front tonight and become gusty at times.

CYS WATCHES/WARNINGS/ADVISORIES

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