textproduct: Western and Central Wyoming

KEY MESSAGES

- Widely scattered rain showers and thunderstorms push in from the west early Tuesday morning around and after sunrise with 60-80% coverage west of the Divide spreading east in the evening and overnight into Wednesday.

- Strong southwest to northwest winds Tuesday and Wednesday with critical fire weather conditions expected coupled with low minimum relative humidity values east of the Divide.

- Cold front pushes through Tuesday afternoon and into the late evening hours giving way to seasonable temperatures into Wednesday and Thursday.

- Drier conditions and a warming trend for Friday and into the weekend.

DISCUSSION

Issued at 130 AM MDT Tue Jun 9 2026

WV imagery continues to show the Pacific northwest upper level trough to the west with the PFJ extending cyclonically through Idaho and into Montana. Jet max of around 120kts continues to deepen the disturbance with ample diffluence aloft. IR shows the cooler cloud tops inching closer to the WY/ID state line that will slowly makes its way west of the Divide bringing with it increasing shower activity by sunrise Tuesday morning expanding to the Divide by late morning. Widely scattered showers and possible isolated thunderstorms through much of the day Tuesday, but with less instability compared to Monday that should see minimal lightning activity in regards to fire weather concerns. Currently, QPF amounts do not look substantial and some mountain snow west of the Divide to include the Winds in the highest of the elevations about 11-12kft. Nothing of note amount wise but intriguing for June and those in the backcountry enjoying the Wyoming great outdoors. It will be helpful for Gannett Peak climbers later in the month keeping the infamous bergschrund closed into early July before it starts its slow opening making for harder glacier travel. The Bighorns will look to get in on the action by Tuesday afternoon as upslope rain shower activity expands east of the Divide for the higher elevations but no snow looks to come to fruition not being as high in stature.

The best chance for storm activity will come mid to late afternoon along the west to east moving cold front clashing with the drier warmer air to the east. The cold front looks to cross the Divide towards sunset Tuesday evening pushing east of the CWA before midnight. This will limit and storm development with more of a lack of moisture content east of the Divide losing the daytime heating Tuesday. Cooler temperatures west of the Divide with earlier FROPA, but temperatures consistent with Monday for points east. Wednesday will be the coolest day of the week with more seasonable temperatures expected CWA wide as the upper level disturbance shifts more northeastward bringing the precipitation chances limited to northern areas of the CWA from Yellowstone across the northern Absarokas and Bighorn Basin to the Bighorn Mountains themselves. Shower activity will exit to the east and northeast by late Wednesday evening and becoming mostly dry overnight into Thursday. Diurnal shower activity for higher elevations expected Thursday afternoon/early evening for Thursday onward as northwest flow aligns back across the northern Rockies. Upper level ridging builds back in across the western United States with increasing convergence aloft to aid in a warming trend Friday and into the weekend.

The other weather element to expect will be winds for Tuesday and Wednesday. Ahead of the aforementioned cold front, expect gusty southwest winds, strongest east of the Divide with gusts up to 40-55mph and in particular the usual wind corridor from Sweetwater to Natrona and Johnson Counties from late Tuesday morning through much of the day. Behind FROPA, expect a shift to west/northwest winds continuing to be quite gusty but not as strong into the overnight hours through Wednesday morning. These winds will once again pick up by late in the morning through sunset before finally subsiding towards sunset and overnight into Thursday as skies improve allowing for more radiational cooling and inversion to set up near the surface. Thursday onward, expect light winds but still breezy back to normal for Wyoming through the end of the week and over the weekend. Northwest to west upper level flow continues into next week with longer term model solutions showing the next best chance for a bigger weather disturbance come mid following week.

AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/

Issued at 949 PM MDT Mon Jun 8 2026

A weather system moves into western Wyoming tonight pushing east of the Continental Divide Tuesday afternoon. Conditions will remain VFR for most terminals, but expect increases in cloud cover and lowering of CIGS during the TAF period, especially west of the Continental Divide. The best chance of MVFR conditions is at KJAC Tuesday morning, with a PROB30 of MVFR VIS and CIGS due to rain showers. Isolated thunderstorms will develop Tuesday afternoon, which may briefly drop VIS to MVFR in the strongest storms.

Rain begins at KJAC/KPNA around 12-13Z and ends mid-afternoon Tuesday as a cold front pushes east through the area. PROB30 groups for thunderstorms have been added for KPNA, KRKS, and KWRL Tuesday afternoon. Other terminals have a low chance (10-20%) of a rain shower or thunderstorm Tuesday afternoon, which is not enough to include in the TAF at this time.

Wind will remain breezy at most terminals tonight with the weather system approaching. Wind will increase quickly Tuesday morning across the area. On average wind will be 15-25 knots, with gusts of 20-30 knots. Strong wind will occur at KCPR, KRKS, KRIW, and KLND. At these terminals wind will average 20-35 knots, with gusts of 30- 45 knots Tuesday afternoon. The wind will shift from west-southwest to northwest behind the front. Wind should remain southwesterly at KJAC behind the front. Mountain obscuration will become prevalent for western mountains tonight through Tuesday morning, with much improvement Tuesday afternoon into Tuesday evening.

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 Tue Jun 9 2026

Near critical to critical fire weather conditions expected for Tuesday and Wednesday from 9AM to 8PM both days. Red Flag Warning continues for Fire Zone 280 (only zone with critical fuels at this time). Strong winds expected out of the southwest to north of west gusting up to 40 to 55 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 into the weekend, but with less wind expected seeing only breezy conditions up to 15 to 25 mph.

RIW WATCHES/WARNINGS/ADVISORIES

Red Flag Warning from 9 AM this morning to 8 PM MDT Wednesday for WYZ280.