textproduct: Cheyenne

KEY MESSAGES

- Near to record warmth expected Wednesday under high pressure aloft. A Fire Weather Watch is in effect Wednesday for the northern Nebraska panhandle.

- Critical fire conditions possible again on Thursday and Friday alongside strong winds and dry conditions. - Next chance for precipitation returns during the weekend alongside cooler conditions.

SHORT TERM /THROUGH THURSDAY/

Issued at 247 PM MDT Tue May 12 2026

An upper-level ridge axis will slide into the CWA throughout the day Wednesday leading to a warm day across the area. 700 mb temperatures will climb to +14C which is above the 97.5th percentile for NAEFS climatology. This will lead to highs reaching the 80s to low 90s and a few locations potentially breaking record highs. Laramie and Rawlins will have the best chance at setting new record high temperatures. Although the area will be under the influence of a ridge, a trough passing north of the CWA will send vorticity maxes in to the Rockies, providing energy for storms to develop during the afternoon hours. Model soundings show a decent amount of CAPE for thunderstorm development. Soundings also show a deeply inverted-V profile with extremely dry surface and low-level. DCAPE values across the CWA are 1500 J/kg and greater, leading to the threat of dry microbursts. Wind gusts in excess of 70 MPH cannot be ruled out. Also, little if any precipitation will actually make it to the ground, leading to dry lightning concerns. Coverage of precipitation will be hard to guage given the strength of the ridge. A few isolated storms are likely, however it is possible for coverage to be more scattered, especially by early evening. Hi-Res guidance shows showers lingering through the overnight hours, with them dissipating by Thursday morning.

Thursday will be a bit drier, but cooler than Wednesday as the trough to the north flattens the ridge. The more zonal flow pattern will lead to strong downsloping westerly winds across the forecast area, which will lead to very dry conditions. High winds will be possible across the wind prone areas early Thursday morning through Thursday afternoon as winds aloft reach 60 kts from strong MSLP and height gradients. In-house guidance even shows a 40 to 50 percent chance of high winds occurring. Did not issue anything at this time since it is a late season wind event and would like to see a few more model cycles first. The combination of strong winds and low relative humidity will lead to critical fire weather conditions.

LONG TERM /THURSDAY NIGHT THROUGH MONDAY/

Issued at 247 PM MDT Tue May 12 2026

Friday will be largely dominated by upper-level zonal flow across much of the region. Temperatures will be quite warm Friday and Saturday as 700mb temperatures increase above about 7 to 10C each afternoon. Highs on Friday are anticipated to be in the low- 70s to mid-80s, with Saturday being slightly warmer in the mid-70s to low-90s. Afternoon minimum humidity values look to remain quite low Friday and Saturday, likely between 10 to 15% each day. Luckily, winds will be on the lighter side across western Nebraska, where fuels are ready to burn, and breezier across southeast Wyoming, where green-up has decreased fire spread potential. That being said, hot and dry conditions may still favor easier fire starts, though rapid fire spread is not anticipated at this time. Instability will start increasing Saturday afternoon with the continued, hot pattern, as well as a cold front pushing through the area. An isolated thunderstorm or two will be possible Saturday, especially across western Nebraska, as is common as we move into the Spring and Summer months.

Saturday into Sunday, an upper level trough will push its way into the Pacific Northwest and send a front through the Intermountain West. Some lobes of vorticity looks to accompany this front to aide in the synoptic lift to help produce some weak showers in the late afternoon to evening time period. By Sunday afternoon, the trough becomes more positively tilted pushing some strong warm air advection and vorticity lobes to give us some possibly strong rain showers through Sunday evening. As this upper level trough pushes through the Intermountain West Sunday night into Monday, the 700mb temperature gradient goes from a warm 8 to 10C and drops down to about -6/-5C giving us a decent chance for a rain/snow mix to possibly snow showers in the higher elevations above 7,0000ft early Monday morning and Monday night. During the day the summer sun is likely to keep all the precipitation as rain outside the mountain peaks for Southeast Wyoming. This trough is the start of an active weather pattern for the work week as we look to get the chance for precipitation almost every other day.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 1142 AM MDT Tue May 12 2026

An upper level ridge will be pushing through the Intermountain West today into tomorrow. Winds are going to be around 10 to 15kts with the occasional sporadic gust to 25kts. Overnight winds look to become Light and variable for the Wyoming terminals. Winds will shift to the south by tomorrow morning and start to gust around 14z for the Panhandle. The pressure gradient will tighten slightly as the ridge compresses against the upper level low centered near Manitoba. So by 15z winds may be 15G25kts with peak gusts up to 30kts by the afternoon for KAIA, KSNY, and KCDR. Peak gusts look to be around 20kts for KBFF.

CYS WATCHES/WARNINGS/ADVISORIES

WY...None. NE...Fire Weather Watch from Wednesday afternoon through Wednesday evening for NEZ434-435.