textproduct: Cheyenne

KEY MESSAGES

- Widely scattered strong to severe afternoon thunderstorms are expected today. All severe hazards are possible.

- Thunderstorm chances continue on Wednesday and Thursday with greater coverage in storms that will increase the potential for localized flooding concerns, particularly over recent burn scars.

- Warming temperatures, falling humidity, and increasing winds will increase fire weather concerns over this upcoming weekend.

SHORT TERM /THROUGH TONIGHT/

Issued at 151 AM MDT Tue Jun 23 2026

Rinse and repeat, we will have another day of strong to severe storms across the CWA southeast of a line from Casper to Rawlins. This is where storms will initiate and drift off to the east, sometime between 1-3PM. This go around, the Storm Prediction Center (SPC) has Cheyenne smack dab in the middle of an enhanced risk (3 out of 5), with all modes possible. Lets cut to the chase, with an abundance of low-level moisture firmly in place and ample instability (MLCAPE values may approach 3000 J/kg later this afternoon), this will set the stage for widely scattered strong to severe thunderstorms. This coupled with strong vertical wind shear, supercells are likely that will bring all modes of hazards. Expect large hail (up to 4"), strong winds (up to 75mph), and discrete supercells producing tornadoes. In addition, there is the threat of landspouts and potential flash flooding. Hi-res models are in good agreement showing fairly widespread activity across southeast Wyoming and the Nebraska Panhandle. But first, with all the moisture yesterday and overnight, patchy fog and low clouds are once again a possibility later this morning, with it eroding by noon as model solutions depict. Taking a brief look at temperatures, highs today will be slightly cooler with highs only topping out in the mid 70s while lows tonight (Tuesday night) dip into the low 50s.

LONG TERM /WEDNESDAY THROUGH MONDAY/

Issued at 215 PM MDT Mon Jun 22 2026

Wednesday...West northwest flow aloft continues, while a shortwave trough aloft moves over eastern Wyoming near peak heating. A decent low level convergence boundary will stretch across southeast Wyoming in the afternoon, with an 850 and 700 mb theta-e ridge axis extending from Casper to Cheyenne. Expecting scattered afternoon and evening thunderstorms to initiate in the convergence boundary, and with CAPE of 1000 to 2000 J/kg and bulk shear values near 45 knots, we should see isolated to scattered strong to severe thunderstorms develop from afternoon through early evening, and concur with the Storm Prediction Center outlook of marginal to slight risk over our eastern half of counties.

Thursday...Westerly flow aloft continues, and with surface low pressure developing over south central Wyoming producing a convergence axis from Douglas to Laramie, and plenty of low and mid level moisture, and 850/700 mb theta-e ridge axis from Casper to Cheyenne, along with CAPE of 1000 to 1800 J/kg and bulk shear near 50 knots, we anticipate some storms to become severe, with large hail and damaging winds as the primary threats east of I-25, with some locally heavy rainers due to flow aloft.

Friday...Low amplitude ridging develops over our forecast area, with some drier air noted advecting in. However, still expect isolated to widely scattered afternoon and evening thunderstorms to form along a low level convergence axis along the I-25 corridor. A few strong and possibly severe storms may occur.

Saturday...The flow aloft turns southwest and increases in speed, with considerably drier air moving across our counties, producing a dry day with a warming trend as 700 mb temperatures spike near 19 Celsius.

Sunday and Monday...A broad trough aloft develops across the northern and central Rockies, with dry southwest flow aloft, leading to only isolated to widely scattered thunderstorms in the afternoons and evening. Slightly cooler compared to Saturday in the wake of a cold frontal passage.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 1144 PM MDT Mon Jun 22 2026

The thunderstorms are finally weakening and moving out of the area. The Hi-res models have low clouds pushing in tonight for majority of the terminals. Around 12z the winds look to be out of the north then slowly push east after 21z. Severe thunderstorms are expected to start around 21z for KCYS and KLAR and eventually push into the Nebraska Panhandle after 00z. All hazards including tornadoes will be possible with these storms just like they were tonight.

CYS WATCHES/WARNINGS/ADVISORIES

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