textproduct: Cheyenne

KEY MESSAGES

- Early morning showers and thunderstorms possible today, mainly across southeast Wyoming. Another chance of thunderstorms expected Saturday.

- Mostly dry and warmer weather will prevail for Sunday through Thursday, with breezy conditions in the afternoons and evenings.

SHORT TERM /THROUGH SUNDAY/

Issued at 225 AM MDT Fri May 8 2026

Short term forecast is on track early this morning with a pretty good coverage of showers and embedded thunderstorms continuing to rapidly push southeast over and just west of the I-25 corridor. Multiple lines of showers will continue to develop ahead of the weak trough axis as it pushes into the I-80 corridor over the next few hours. This slow moving upper level disturbance, which hasn't quite moved into southeast Wyoming yet, will take it's time moving into the northern Front Range...before it ejects east later this morning. Expect rainfall to quickly dissipate between 6 and 9 AM. Before that, some pretty good rainfall rates have been observed with this activity with upstream mesonet sensors showing a quick 0.25 inches of rainfall. Expect clearing skies by mid to late morning with temperatures near or slightly above average for early May. Also, added some fog for portions of the Laramie Range and the more sheltered valleys west of the Laramie Range early this morning.

Northwest flow aloft will continue today behind the upper level disturbance as it digs southeast into the central plains. A few models show some rain shower activity developing along the Laramie Range during the afternoon, but not as many as yesterday. The ECMWF continues showing widely scattered showers over the I-80 corridor and the Laramie Range. However, most model guidance and GFS & NAM soundings keeps things dry with soundings showing an elevated temperature inversion/CAP around 600mb with a pretty dry boundary layer. Kept POP around 10 to 15 percent for now and will see how quick we dry out late this morning and this afternoon.

For the weekend...all models show a transitory short-wave ridge quickly moving southeast across the area early Saturday morning before the next upper level trough digs southeast in northwest flow aloft. This trough appears stronger than the one this morning/late Thursday, and will have a surface and midlevel cold front which is forecast to push across the high plains Saturday afternoon. Expect scattered to numerous showers and possibly scattered thunderstorms to form from north to south during the day, starting off in east central Wyoming and the northern Nebraska panhandle earlier in the day, with activity impacting the I-80 corridor by mid to late Saturday afternoon. There is some pretty good forcing with this feature, so will need to keep an eye on some stronger thunderstorms forming east of the I-25 corridor with CAPE values nearing 800 to 1000 j/kg. It looks a bit too dry for strong thunderstorms west of the Laramie Range, but will continue to monitor the potential for stronger wind gusts associated with convection. Continued to keep POP between 40 to 70 percent with scattered to numerous coverage expected. Expect some of this activity, especially along the I-80 corridor, to linger well into the evening hours Saturday night.

For Sunday, all models show a drying trend as the fast moving upper level trough axis slides southeast into the southern plains. Upper level ridge axis across the Great Basin region is forecast to nudge eastward into Wyoming and Colorado, resulting in a drier airmass and increasing temperatures at the surface and aloft. Sunday afternoon will be pleasant with highs in the upper 60s to mid 70s for most of the area.

LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/

Issued at 131 PM MDT Thu May 7 2026

Monday...The next shortwave trough aloft moves across eastern Montana and the Dakotas, sending its associated cold front into northeast Wyoming and perhaps our far northern counties from Douglas to Chadron in the afternoon. Still though, even with cold frontal forcing, dry conditions should prevail due to dry low and mid levels. Moderate confidence in breezy to windy conditions as the low and mid level gradients strengthen for Monday afternoon. Prefrontal lifting and 700 mb temperatures near 12 Celsius will produce summer like maximums in the upper 70s to near 90 degrees.

Tuesday...Brisk northwest flow continues, and dry conditions remain with scarce low and mid level moisture availability. Cooler temperatures in the post cold frontal sector as upslope north and northeast winds develop.

Wednesday...Another warming trend ensues as 700 mb temperatures reach 14 Celsius, yielding highs in the upper 70s to near 90 degrees. The dry northwest flow aloft prevails, and with warm mid level temperatures producing enough convective inhibition, no showers or thunderstorms are anticipated.

Thursday...The ridge aloft moves further east over western Wyoming. Some pseudo like monsoonal moisture will affect western Wyoming and western Colorado, though it looks likely the scattered showers and isolated thunderstorms will be mainly west of our forecast area. Slightly cooler temperatures due to a small drop in 700 mb temperatures.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 550 AM MDT Fri May 8 2026

Upper level disturbance currently moving southeast across the area and into Colorado early this morning. Improving conditions and decreasing cloudiness expected by 15z with any remnant rain showers ending.

HAZARDS/WEATHER TRENDS: VFR conditions will prevail across the area over the next 24 hours in between weather systems. West to northwest winds will occasionally gust around 25 knots late this morning and this afternoon.

CYS WATCHES/WARNINGS/ADVISORIES

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