textproduct: Western and Central Wyoming

KEY MESSAGES

- Widespread near critical to critical fire weather conditions continue until 8PM tonight due to gusty winds and low relative humidity. A Red Flag Warning remains in effect for portions of Natrona County until 8PM.

- Strong westerly winds expected through 9PM with widespread gusts of 35 to 55 mph. Higher elevations and wind prone locations could see gusts around 60 mph.

- Seasonable temperatures, breezy, low humidity, and limited rain and thunderstorm chances (less than 20 percent) Thursday through Saturday morning. Rain and thunderstorm chances (20 to 60 percent) Saturday afternoon through Monday.

UPDATE

Issued at 118 PM MDT Wed Jun 10 2026

19Z water vapor imagery shows strong zonal flow aloft with the upper level low situated over northern Montana and its axis extending into Idaho. The forecast has remained consistent that the upper low ejects to the north and east today. As it does so, the trough axis and it's associated cold front will traverse across Wyoming this evening. Winds aloft will strengthen as the trough axis approaches, with an upper level jet maximum ranging from 110kts to 130kts at it's peak this evening. In addition to the strong winds aloft, a sharp surface pressure gradient will be present through the day. These features will allow for the ongoing gusty winds to be maintained until the front moves through in the 8PM to 10PM timeframe. Mid-day observations across the area are showing wind gusts ranging from 35 to 55 mph. Moisture is largely confined to northern Wyoming, so the southern half of the state remains dry. Near critical to critical fire weather conditions are expected due to the strong gusty winds and low humidity until roughly 8PM this evening.

The forecasted shower and thunderstorm chances (40%-80%) and location (northern Wyoming) remains on track today and overnight. 19Z/1PM radar imagery is picking up on scattered showers from Yellowstone National Park to the northern Bighorns. As instability increases this afternoon, coverage is expected to increase across northern Wyoming as well. As the cold front treks across the state this evening, isolated showers and a few rumbles of thunder cannot be ruled out across central Wyoming from 6PM to 10PM. Otherwise, light shower chances (up to 40%) still exist tonight across the Bighorn Basin. One change made to this afternoon's forecast is that post frontal northerly winds were increased across northeastern Johnson for Thursday. Gusty 35 to 45 mph winds are forecast between roughly 9AM and 2PM Thursday, with an occasional gust closer to 50 mph not out of question.

DISCUSSION

Issued at 130 AM MDT Wed Jun 10 2026

IR shows much clearing and improved skies across much of the southern half of the CWA with the cooler cloud tops to the north and east over Montana and into the High Plains. WV depicts the main finger of the PFJ becoming more disoriented across the northern Rockies as the main upper level trough shifting eastward and retreating north along the MT state line. As a result, the lingering rain showers are constrained for northern parts of the CWA coming off the Absarokas through the Bighorn Basin to the upslope of the Bighorns. These will continue to wain into the early Wednesday morning hours through around sunrise.

The associated deformation zone will continue to linger across the north for much of Wednesday before the L/W trough exits east into the upper Great Plains by midnight and into Thursday morning. Rain shower activity more limited Wednesday afternoon associated with another weaker cold frontal passage losing its luster before hitting the southern half of the CWA where the near surface is much drier. Gusty outflows the main concern on top of the already windy conditions east of the Divide. Winds have wained overnight but will again increase by mid Wednesday morning as the gradient remains in place and mixing occurs after a weak inversion erodes with daytime heating. Gusts up to 35 to 55mph likely, highest along the Wind Corridor once again through the afternoon hours diminishing towards sunset with radiational cooling under continued improved skies for Wednesday night. The last gasp of the backside of the upper level disturbance comes after midnight with some scattered rain showers pushing across the northern Bighorn Basin into Johnson County exiting by sunrise. Light snow for the higher elevations above ~12kft expected for the Absarokas to the Bighorns but minimal, if any, impacts expected down the passes.

Regardless, expect Wednesday to be the coolest afternoon of the week another 5 to 10 degrees cooler than Tuesday even becoming less than average for this particular June day. Beyond that, more seasonable Thursday with a warming trend into the weekend and next work week. Isolated higher elevation shower activity expected Thursday through the weekend with northwest to westerly flow continues across the upper Rockies but limited in coverage. Breezy winds expected but not near what has occurred Tuesday and Wednesday leading to a more limited to elevated fire weather concern Thursday onward. Beyond the weekend, upper level ridging builds in from the southwest keeping a similar pattern for much of next week. Longer term model solutions continue to ping the next bigger disturbance to occur by week's end into the following weekend.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 1105 AM MDT Wed Jun 10 2026

VFR conditions are expected to prevail across all terminals through the TAF period. Some mid-level clouds will gradually develop during the afternoon. A nearby disturbance will aid in the development of scattered showers and thunderstorms this afternoon/evening. The best chances 10-30% look to remain across northern and western WY, such as KJAC, KCOD, and KWRL. Other terminals such as KPNA and KCPR have lesser chances but may still see a nearby shower or two. Another round of light showers look possible late Wednesday evening into early Thursday morning. These showers are expected to remain across northern WY with KCOD and KWRL having the best chances. Wind will once again be gusty across all terminals. Winds of 15 to 30 knots will be possible this afternoon with periodic gusts of 30 to 40 knots. Stronger gusts in excess of 40 knots cannot be ruled out at KRKS, KCPR, KPNA, and KBPI. Winds decrease shortly after sunset for nearly all terminals with light to breezy conditions lingering for the overnight. Skies are expected to clear out during the morning hours Thursday leading to nearly all terminals seeing SKC conditions to end the period.

FIRE WEATHER

Issued at 130 AM MDT Wed Jun 10 2026

Near critical to critical fire weather conditions continue Wednesday from 9AM to 8PM. Red Flag Warning continues for Fire Zone 280 (only zone with critical fuels at this time). Strong winds expected out of the 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 until 8 PM MDT this evening for WYZ280.