textproduct: Western and Central Wyoming

KEY MESSAGES

- Temperatures in the 70s and 80s today with gusty 20 to 35 mph winds this afternoon. Isolated virga showers are possible (15-20 percent) from Rock Springs to Midwest and will be capable of 40 to 55 mph gusty outflows.

- Rain and thunderstorm chances (40-90 percent) are forecast late tonight and Tuesday across western Wyoming and again on Wednesday across northern Wyoming.

- Gusty southwest to west winds across the entire area on Tuesday and Wednesday with gusts of 35 to 50 mph. There is high confidence in elevated to near critical fire weather conditions for most locations, especially Wednesday.

- Near normal temperatures, breezy, low humidity, and limited rain and thunderstorm chances (less than 30 percent) Thursday through Saturday.

DISCUSSION

Issued at 130 AM MDT Mon Jun 8 2026

IR shows cooler cloud tops over Idaho mainly associated with the upper level low over the Pacific northwest. WV depicts the PFJ around it pushing into much of Montana with jet max up to 120-130kts allowing for the low to continue to slowly deepen with increased divergence aloft. Any shower activity has diminished and pushed east of the CWA with mainly dry conditions expected Monday. However a couple of isolated storms look to develop over eastern Sweetwater to southern Natrona counties after 2-3PM Monday afternoon exiting east and northeast by 6-7PM. Severe weather is not expected, but stronger outflows may be had if enough of the cap breaks with warmer 700mb temps up to 40-50 mph possible but confidence low at this point in time (20-30%).

The next shortwave around the aforementioned low will begin to push in out west from Idaho after midnight into early Tuesday morning. More widely scattered rain shower and thunderstorm activity expected but severe weather again not expected due to not as warm temperatures, and thus, less instability to be had for these storms to tap into west of the Divide. These spread east after sunset Tuesday night into Wednesday, with that being the "coolest" day of the week behind a stronger cold front. Ahead of the front, expect gusty southwest winds east of the Divide, possibly seeing widespread gusts over 50 mph pushing close to high wind criteria. Confidence not great on how strong the winds will be, and thus, no headlines are issued at this time. Behind the aforementioned cold front, expect winds to be more west to north of west with continued stronger gusts, especially east of the Divide once again. The highest winds look to be pinpointed across the wind corridor as expected from Sweetwater to Natrona Counties and up to Johnson. Buffalo and point north coming down from Sheridan looks to be a point of emphasis to keep an eye on as the models have not handled how high winds can be here, especially after Sunday evening's event behind the weaker of the cold fronts to affect the CWA days apart.

The upper level low looks to fill and start to progressively push east across the upper Rockies Wednesday night. Any shower activity lingering into Thursday morning will go with it as dry conditions push back in for the rest of the work week and into the weekend. Increased convergence and a building upper level ridge pushes over the region Thursday into Friday, and especially over the weekend. Back to warmer than average temperatures going into next weekend. Northwest flow aloft continues during this timeframe, so weak higher terrain storms are still possible each afternoon and early evening based on diurnal trends. Longer term models continue this pattern not seeing any break in this upper level flow until at least 10 days out.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1122 AM MDT Mon Jun 8 2026

Dry west-southwest flow aloft today ahead of a longwave trough approaching the Pacific Northwest Coast. Weak, high-based convection is possible in a swath from around KRKS to KCPR between 20Z/Monday to 02Z/Tuesday. Gusty outflow wind gusting 35-45kts, locally higher, would be the primary hazard given inverted-v profiles. Gusty southwest surface wind 12-25kts develops at most terminals between 19Z-22Z/Monday before decreasing around sunset Monday. KCPR should again see an easterly wind 10-15kts for 6 to 8 hours. However, as the upstream trough nears Wyoming southwesterly surface wind will increase late tonight and Tuesday morning regionwide. All terminals to be VFR through the forecast period with the possible exception of KJAC as the trough reaches far west Wyoming Tuesday morning. There is a 30-50 percent chance of MVFR ceilings in light rain as the main moisture push moves through KJAC after 12Z/Tuesday. This has necessitated a PROB30 group. Mountain tops along and west of the Continental Divide frequently obscured after 10Z/Tuesday.

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 130 AM MDT Mon Jun 8 2026

Elevated to near critical fire weather conditions expected Monday with strongest winds west of the Divide gusting up to 25 to 35 mph out of the southwest. humidity values in the 10 to 20 percent range for much of the area.

Near critical to critical fire weather conditions expected for Tuesday and Wednesday afternoons and evenings with a fire weather watch issued for zone 280 (only zone with critical fuels at this time). Stronger winds expected out of the southwest to west gusting up to 40 to 50 mph in many areas east of the Divide, and up to 30 to 40 mph to the west. Humidity values will be as low as 10 to 15 percent, driest in the wind corridor from Sweetwater to Natrona Counties.

Low humidity values continue for Thursday and Friday but with less wind expected seeing only breezy conditions up to 15 to 25 mph.

RIW WATCHES/WARNINGS/ADVISORIES

Fire Weather Watch from Tuesday morning through Wednesday evening for WYZ280.