textproduct: Cheyenne

KEY MESSAGES

- Our continued chances of severe weather wrap up today with a slight risk (2/5) primarily for our northeastern zones.

- Temperatures will slowly warm to well above seasonal averages by the weekend, with a quick cooldown on Monday before further warmth returns into the middle of next week.

SHORT TERM /THROUGH FRIDAY NIGHT/

Issued at 1233 AM MDT Thu Jun 4 2026

Latest analysis of today's thunderstorm setup remains largely dependent upon where the dryline sets up. Current analysis of high resolution guidance favors the Nebraska Panhandle with a surface low right along the NE/SD/WY border area. With a cold front along this low and draping into Wyoming, it wouldn't be out of the question to get some development into Laramie County before we see the main show across our northeastern zones in Niobrara County and the northern Panhandle, but the severe potential in southeastern Wyoming will be very limited. Primarily the strongest storm activity should be limited to the tri-state area as mentioned above (at least for our CWA) where instability will be most conducive (500-1000 J/kg of MUCAPE, isolated 1500) alongside SRH values of 200-300 m2/s2. Most of our convective allowing models show some scattered development across the area with a stronger storm or two moving across our northeastern zones between 21Z-02Z, with many indicating another quick stronger development around 06Z in Niobrara County or the northern Nebraska Panhandle before activity should fully exit during the overnight hours. While storms will be capable of an isolated tornado alongside some stronger winds (DCAPE values looking hearty in the 1000-1500 range), overall the primary hazard expected will be hail with these storms, including larger hail in the 1.5-2 inch range.

Otherwise the other notable feature for today will be gusty winds under an enhanced pressure gradient for our far western zones in Carbon and Albany Counties. While overall speeds are not expected to near even close to high wind warning criteria, the combination of these gusty winds and dry surface conditions will lead to elevated fire weather concerns. Last contact with partners suggests fuels are still not conducive of a critical environment and the need for a Red Flag Warning, but the area should be watched from how dry it has been alongside this elevated environment. Once the shortwave promoting this activity exits the region today, Friday will see high pressure taking control as a ridge moves in over the Central US while a Pacific trough sweeps across the western portion of the country. Between these systems we should encounter subsident flow cutting off pretty much all chances of precipitation while warming us significantly as we move into the weekend. For Thursday and Friday however, we should see relatively similar conditions as highs range in the 80's to low 90's. But by the weekend, look for temperatures to rocket into the upper 80's to 90's, and even some triple digits making their first appearances of the year.

LONG TERM /SATURDAY THROUGH WEDNESDAY/

Issued at 248 PM MDT Wed Jun 3 2026

Drier and hotter weather will return to the area Friday through the weekend. On the synoptic scale, an upper level low will dive into the Pacific Northwest, which will then amplify the downstream ridge over the Rockies and Plains. A very dry airmass with considerable subsidence will move in overhead Friday. An inversion aloft around 600-mb will limit the development of convective instability, likely suppressing most if not all afternoon shower and thunderstorm activity. 700-mb temperatures will climb to around +10 to +15C, supporting widespread highs in the 80s. The day may start off with gusty northwest winds in the wake of a front passing through during the morning hours, but expect this to weaken through the day.

This weekend will feature the first taste of the season of real summer heat across the area. As the ridge amplifies aloft, expect 700-mb temperature to climb to around +13 to +18C by Saturday. This should easily be the hottest day of the year so far across the area. Interestingly, for Scottsbluff, Sidney, and Alliance, the hottest day of 2026 through June 3 occurred in March! This should be easily bested Saturday, with widespread mid to upper 80s along the I-80 corridor in Wyoming, and 90s elsewhere. Locations around Scottsbluff, Torrington, Chadron, and Crawford have a 40 to 50% chance to see their first 100 degree day of the season. While it will certainly be hot, most locations have forecasts several degrees away from daily record highs. The hot temperatures moving down to the surface will lead to a deeper mixed boundary layer and thus a weaker or absent inversion aloft. We should be able to get a few high-based showers with perhaps a rumble of thunder going on Saturday, but the chance for rainfall actually reaching the ground is fairly low.

The Pacific trough will approach from the west on Sunday, knocking down temperatures by several degrees for the western half of the forecast area. East of Cheyenne's longitude, highs will be slightly cooler, but closer to Saturday's values with another day of widespread upper 80s to mid 90s. Look for a few widely scattered showers and thunderstorms Sunday afternoon and evening, but again, rainfall may be limited due to the warm and dry boundary layer. A leading shortwave ejecting from the western Trough will pass through Monday, knocking down temperatures and also perhaps providing some lift for additional convective activity. Increased chances for showers and thunderstorms will continue through the early part of next week, but the details remain quite uncertain several days out.

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/

Issued at 500 AM MDT Thu Jun 4 2026

This morning's primary concerns lie across northern Nebraska Panhandle where low clouds and some fog have been noted. While conditions have cleared at KAIA, KCDR continues to see low clouds bringing MVFR conditions. Have continued these low clouds for KCDR, and have added VCFG for KAIA in case the fog is able to move back over the site before clearing around 15Z both sites. Otherwise VFR conditions expected through the afternoon all remaining sites, with a chance of thunderstorms again this afternoon and evening, primarily impacting NE terminals. Development may stay just outside of KBFF, and there is also a chance of localized activity forming near KCYS as well. For now, have left TS outside of these two sites, while the remaining NE have PROB30 groups for storm potential. Low clouds and possible fog expected to return again overnight for KCDR and possibly KAIA, but have only introduced potential at KCDR as of this update. Winds breezy WY terminals with any terminals seeing storms potentially having variable and strong winds.

CYS WATCHES/WARNINGS/ADVISORIES

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