textproduct: Cheyenne

KEY MESSAGES

- The potential for a few afternoon and evening strong to severe thunderstorms will continue through Thursday.

- Temperatures will slowly warm to well above seasonal averages by the weekend as thunderstorm chances become more isolated.

SHORT TERM /THROUGH THURSDAY NIGHT/

Issued at 248 PM MDT Wed Jun 3 2026

Another round of storms is expected later this afternoon, albeit not as widespread as the last few days. With more northerly flow dominating most of the forecast area today, storm coverage will mostly be limited to the southern half of the CWA. This is where model soundings as well as current mesoscale analysis show an environment conducive for marginally severe storms this afternoon and evening. Radar shows a few storms going up over the high terrain of Colorado. This will eventually occur by mid-afternoon along the Laramie Range and dryline positioned in the vicinity. Storms will push eastward into the Nebraska panhandle by late afternoon. Hi-Res guidance is more keen on storm clusters today than discrete cells, posing more of a severe wind threat than a hail threat. With DCAPE values in the panhandle exceeding 1000 J/kg, severe wind gusts will be possible in storms. There is also roughly 1000 J/kg of MUCAPE, so embedded, but isolated, large hail cannot be ruled out. Storms will push out of the panhandle later this evening, leading to quiet conditions overnight.

An interesting forecast is expected headed into the day Thursday. Surface southerly flow will be present during the morning hours, advecting moisture into areas east of the Laramie Range. However, this will be short-lived as a progressive shortwave treks across Wyoming throughout the day. This shortwave will turn winds more westerly, drying out the low and mid-levels across the forecast area. As a result, models, both global and mesoscale analyze the dryline pretty far eastward compared to the previous few days. The dryline could range anywhere from the Wyoming/Nebraska border to the eastern Nebraska panhandle. Depending where the dryline sets up, this could profoundly affect the amount of storms the area sees, or if storms even impact the area at all. Hi-Res guidance is currently not bullish enough to say storms won't occur, but an isolated severe storm or two could be possible. The HRRR also shows gusty showers across the area. This lines up with GFS soundings showing strong inverted-v profiles from the dry low and mid- levels. DCAPE values do exceed 1000 j/kg in parts of the Nebraska panhandle so cannot rule out severe wind gusts in these gusty showers. Model soundings from the GFS do show an interesting feature overnight around Chadron. Pretty good elevated convection will exist as well as a surge of low-level moisture. This could produce some strong storms overnight, mainly for the northern counties of the Nebraska panhandle as well as Niobrara County.

LONG TERM /FRIDAY THROUGH TUESDAY/

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 /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 600 PM MDT Wed Jun 3 2026

Lower coverage of thunderstorms compared to the last several days as an upper level trough is far south of the forecast area today and this evening. Expect an isolated line of thunderstorms to push across the southern Nebraska Panhandle between 00z and 04z.

HAZARDS/WEATHER TRENDS: Thunderstorm activity this evening will mainly impact KSNY with brief IFR conditions and gusty winds between 00z and 03z. Otherwise, VFR conditions will prevail at all terminals tonight and into Thursday morning. Westerly winds will increase over the southeast Wyoming terminals with gusts between 25 to 35 knots possible after 16z. Slight chance of some fog and/or low CIGS at KCDR with probabilities of VIS < 3SM between 15% to 25%.

Can't rule out thunderstorms impacting KAIA later this evening, but not as confident as KSNY due to thick high clouds over the area.

CYS WATCHES/WARNINGS/ADVISORIES

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