textproduct: Western and Central Wyoming

KEY MESSAGES

- Widespread critical fire weather conditions for Sunday afternoon and evening given low humidity, gusty wind, and hot temperatures.

- Thunderstorm chances Sunday (20-30% coverage), with a couple of strong to severe storms possible (30-40%) across the eastern Bighorn Basin and Johnson County. Damaging winds and hail the main threats for late afternoon to early evening before sunset.

- Active pattern continues for much of the work week Monday through Thursday before ridging sets in for Friday and into next weekend.

DISCUSSION

Issued at 200 AM MDT Sun Jun 7 2026

WV imagery currently shows the deep upper level trough across the Pacific northwest with the PFJ pushing cyclonically around it with a positive tilt just to the west of the state. IR shows the cooler cloud tops over eastern Idaho into central Montana that will slowly push east into the CWA by Sunday morning expanding throughout the day. Some light rain showers across the west that will dissipate by sunrise with another round of scattered thunderstorms expected to develop by late morning across the Bighorn Basin. Gusty outflow winds expected with this occurrence but severe weather is not expected through early afternoon. As this pushes northeast by mid afternoon ~3-4PM, another area of development expected to off the leeward side of the Absarokas by 4-5PM pushing across the north central portions of the basin expanding to the Bighorns. These look to form more of a line across the pre-frontal troughing with winds again the main concern with possible severe thresholds being met.

Attention turns to the more discrete cells come 6PM onward towards sunset as the weak storms across Sweetwater County push across Natrona into Johnson County. This will be when hail could be more of a threat before quickly pushing northeast out of the CWA before sunset around 8PM. With the ample surface convergence and modest lapse rates, larger hail possible with moderate confidence for severe thresholds up to a quarter. CAPE values over 1500 J/kg ahead of FROPA will be conducive to this occurrence with low level shear aiding in hail growth over 30 knots. The more upscale growth will occur after sunset and northeast of the CWA into western South Dakota. These strong to severe storms for hail potential will be short lived for our CWA with the time frame of concern between 6-8PM. Otherwise, any other stronger storms for the eastern Bighorn Basin across the Bighorns and northern Natrona County will be more of a wind threat but below severe thresholds at this point in time. A long Sunday night looks to be in store severe wise for Rapid City and point north and east into Monday morning.

Beyond the storm activity, expect FROPA to occur north to south by late afternoon and into the late evening hours. Warm temperatures ahead of the front will still give way to above average temperatures but not record breaking as it was Saturday due to the increased cloud coverage with this first shortwave. Fire weather conditions expected to be near critical to critical ahead of FROPA with gusty southwest winds to develop by mid to late Sunday morning, strongest across Sweetwater to Natrona Counties for the wind corridor up to 30 to 40 mph likely. Winds shift with more of a northern component behind FROPA pushing through the CWA after midnight and into early Monday morning diminishing by sunrise.

Continued active pattern with the aforementioned L/W trough to the northwest with a multitude of shortwaves through Thursday. With cooler temperatures, severe weather is not expected but expect a daily afternoon/evening dose of scattered storm activity along with elevated fire weather danger as well. The coolest day of the week looks to be Wednesday with a stronger cold front with the the more widely scattered rainfall activity expected. Beyond Thursday, the low finally exits to the east as increased convergence aloft and upper level ridging builds back in for Friday and into next weekend with a warming and dry trend expected.

AVIATION /06Z TAFS THROUGH 06Z MONDAY/

Issued at 1020 PM MDT Sat Jun 6 2026

Winds will continue to decrease toward the start of the forecast period, as a boundary pushes southward over areas east of the Divide. Winds will be from the north-northwest in the wake of the boundary through 12Z-15Z.

Low light rain chances exist across western Wyoming through 09Z and brings a 30 percent chance of light rain to KJAC. This area of showers will progress eastward through the rest of the morning, reaching areas from KWRL to KRKS after 18Z. Isolated to scattered showers and thunderstorms along this general area, gradually pushing into Johnson County after 21Z. Strong to possibly severe thunderstorms will be possible here between 21Z and 02Z. A heavier shower or thunderstorm could result in brief periods of MVFR visibilities, but confidence in occurrence and duration is low at this time. A cold front will slowly push into far western portions by 18Z, making its way through northern portions of the forecast area and extend from KWRL to KRIW to just west of KRKS by 06Z Monday. Showers will be ending after 02Z, with a 20% chance at KCPR after 04Z. There is also a low probability for MVFR ceilings at KCPR by this time as well, due increasing clouds from the upslope flow behind the front.

Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on icing and turbulence forecasts.

FIRE WEATHER

Issued at 200 AM MDT Sun Jun 7 2026

Near critical to critical fire weather conditions expected for Sunday afternoon and evening due to gusty southwest winds up to 30 to 40 mph and low relative humidity values down to 8 to 12%. Although most fire weather zones are green for fuels (outside of much of Natrona County), fire weather will be of concern for Sunday. Scattered thunderstorms are expected from eastern Bighorn Basin/Fremont County to Natrona/Johnson Counties for late Sunday afternoon and early evening. Gusty outflow winds possible up to 50-60 mph with some of the stronger storms. Active weather pattern continues into much of the work week, but with not as warm temperatures giving way to higher humidity values and only elevated fire weather concerns after Sunday.

RIW WATCHES/WARNINGS/ADVISORIES

Red Flag Warning until 8 PM MDT this evening for WYZ280.