textproduct: Cheyenne

KEY MESSAGES

- Elevated fire weather conditions will continue, mainly west of Interstate 25.

- Afternoon and evening storms will be possible most days through the end of the week along and east of Interstate 25. A few strong to severe storms will be possible each day.

- Hot temperatures expected by the middle of next week.

SHORT TERM /THROUGH SUNDAY/

Issued at 255 AM MDT Fri Jul 3 2026

Current KCYS radar loop early this morning shows some nocturnal thunderstorm activity across the high plains, but mostly in northeast Colorado and western Nebraska...near Sidney. More isolated activity is moving northeast between Cheyenne and Scottsbluff with only a few lightning strikes observed over the last hour. Do not expect this to become strong or severe this morning, with the strong thunderstorms over northeast Colorado forecast to nudge east just outside our forecast area. Overall, expect some isolated to moderate light rain, and gusty winds associated with thunderstorm activity. Otherwise, skies will gradually clear through sunrise.

For the Holiday Weekend, pretty typical July pattern setting up across the region as a ridge of high pressure to our south gradually intensifies over the next 72 hours. 700mb temperatures will gradually climb a few degrees each day with values between 15c to 18c by Sunday afternoon, which translates to high temperatures in the upper 80s to mid 90s. With weak winds, any low level moisture should remain in place and maybe even increase a bit due to some return flow off the Great Plains. In this pattern, expect a continuation of isolated to widely scattered showers and thunderstorms, generally confined to locations along and east of the Interstate 25 corridor into western Nebraska. Expect a few of these thunderstorms to begin initiation over the Laramie Range and/or the Snowy Range, so kept POP over the Laramie Valley near 15% also. Forcing will be limited, but it doesn't take much forcing this time of the year to initiate convection with 1500 to 2500 j/kg of CAPE. CAPE will be present each day, especially across western Nebraska and far eastern Wyoming. Models show the next upper level shortwave (currently over northern Utah at this hour) lifting northeast towards east central Wyoming and northern Nebraska for Friday afternoon. This shortwave should quickly exit the area by this evening, so expect thunderstorms to dissipate by early in the evening this time around. With marginal 0-6km shear profiles, can't rule out some strong to severe thunderstorms, especially north of the North Platte River valley. A Slight Risk of Severe thunderstorms remains over this general area around Chadron and Alliance this afternoon with a Marginal Risk extending as far west as the Interstate 25 corridor. Winds and large hail look to be the main threats, but activity should be pretty isolated (15% to 20% chance). Similar conditions expected on the 4th, but upper level flow will briefly become northwesterly behind the initial shortwave and as another more potent vort max digs south into the high plains later in the day. Expect the best chance for thunderstorms, and severe weather, to shift south towards the Interstate 80 corridor from Laramie to Cheyenne and over towards Sidney Nebraska. SPC has increased the areal coverage of the Slight Risk to include all of western Nebraska and far southeast Wyoming, including Cheyenne. Similar chances for severe are expected with mainly strong gusty winds and large hail the primary threats.

Activity should be more isolated on Sunday as the upper level ridge axis builds northward. Model soundings show enhanced midlevel subsidence, which should help suppress convection and produce more isolated coverage. Kept POP around 15% around the Laramie Range and the adjacent valleys/high plains. The only real forcing present on Sunday will be terrain included low level convergence near the Laramie Range. Models are currently not in good agreement with any mid to upper level forcing, so kept POP minimal for now. Again, this may change quickly as there still will be 1500 to 2000 j/kg of CAPE across western Nebraska.

LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/

Issued at 310 PM MDT Thu Jul 2 2026

Monday...Similar synoptic pattern to Sunday, with enough mid level moisture to produce isolated to widely scattered afternoon and evening thunderstorms, primarily east of I-25 where convergence at low levels will be maximized.

Tuesday...Beneficial rain appears increasingly likely as low and mid level moisture increases markedly, while a shortwave trough aloft, also known as an atmospheric perturbation, moves overhead near peak heating, sparking scattered showers and thunderstorms, especially east of a Douglas to Laramie line, with isolated convection further west in the drier airmass.

Wednesday...Shortwave ridging builds aloft and with decreasing atmospheric moisture in the low and mid levels, expect a corresponding decrease in areal coverage of showers and thunderstorms.

Thursday...Expect a slight increase in afternoon and evening shower and thunderstorm coverage, as a shortwave trough aloft passes overhead near peak heating, though coverage will only be isolated to widely scattered due to warm temperatures aloft producing some convective inhibition, also known as CIN.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 600 AM MDT Fri Jul 3 2026

A weak upper level disturbance will push east across far eastern Wyoming and the northern Nebraska panhandle this afternoon. This disturbance will help initiate strong to severe thunderstorms, mainly for the western Nebraska terminals late this afternoon and this evening.

HAZARDS/WEATHER TRENDS: VFR conditions will prevail with relatively light winds, except near thunderstorms where gusty winds and MVFR VIS are possible. Kept PROB30 groups for all western Nebraska terminals between 22z this afternoon and 02z Saturday.

CYS WATCHES/WARNINGS/ADVISORIES

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