textproduct: Western and Central Wyoming

KEY MESSAGES

- Showers and isolated thunderstorms will continue over western and central portions through 9PM this evening. Gusts of 35 to 45 mph will An additional area of showers will develop over Natrona and Johnson counties by this time and exit to the northeast later tonight.

- Warming trend and mainly dry conditions for the remainder of the week and into the weekend with only limited shower activity each afternoon for northern mountains.

- Elevated fire weather conditions persist, with low humidity values and slight breeze each afternoon this week.

UPDATE

Issued at 1217 PM MDT Tue Jun 30 2026

Highs are about 10 degrees warmer today, approaching normals for the end of June. Some weather models are producing weak showers and thunderstorms between 1pm and 10pm today, associated with a shortwave moving through from the southwest. The main impact from any of these would be gusty outflow winds, generally up to 35 mph. Elevated fire weather conditions will also be in place, especially around Natrona County, as breezy winds 20 to 25 mph occur with minimum humidity 10 to 15 percent.

DISCUSSION

Issued at 100 AM MDT Tue Jun 30 2026

IR currently depicts the main upper level low pushing northeast into the upper Great Plains as the troughing in its wake fills with decreased divergence aloft. WV continues to show distorted fingers of the PFJ, mainly into Canada now with little support to the aforementioned upper level low. Radar activity has diminished for the overnight hours as skies have improved in its wake. This will allow for one more cold morning Tuesday, allowing for western valleys to see mid 20s to mid 30s with minor frost likely for areas of the Upper Green River Basin for the usual suspects between Pinedale to Bondurant.

Otherwise, southwest flow continues aloft Tuesday and Wednesday with a couple minor shortwaves clipping the northern counties but mainly into Montana. Each afternoon and evening will see some limited coverage in shower activity for the northern mountains (10-20%) with a rumble of thunder even less likely <10% due to weak CAPE values less than 100 J/kg. Better chance coming in from the southwest later in the evening towards sunset from Sweetwater to Fremont Counties (30-40%). This pattern continues for the remainder of the work week as a warming trend and mainly dry trend extends through the weekend. A more zonal pattern by the weekend as the high to the south builds in further north increasing convergence aloft and weaker flow. Afternoon high temperatures back to the 80s east of the Divide and 70s to the west for the holiday weekend with no significant winds even to speak of. Each afternoon/early evening will see slight breezes up to 20-25 mph for wind prone areas east of the Divide, but otherwise calm for Wyoming standards. Even with low relative humidity values, fire weather concerns will be limited to elevated throughout the week and weekend. This upper level high continues to build in from the south into next week with some longer term model ensembles showing some record heat coming by mid to end of next week, welcome to July....

AVIATION /06Z TAFS THROUGH 06Z THURSDAY/

Issued at 1002 PM MDT Tue Jun 30 2026

VFR conditions are expected to prevail across all terminals through the TAF period. Conditions are likely to remain dry overnight with a very isolated shower possible nearby KCPR to start the period. Winds decrease to a breeze of 5 to 10 knots possible across all terminals overnight. Winds increase slightly after 18Z Wednesday with most terminals seeing winds of 10 to 15 knots and occasional gusts around 20 to 25 knots. Another round of showers and thunderstorms will be possible Wednesday afternoon shortly after 20Z. The best chances (20- 40%) look to remain west of the Divide and across portions of the Bighorn Basin. KJAC, KPNA, KBPI, KWRL, and KCOD have VCTS groups as uncertainty remains if there will be direct impacts from any nearby showers or thunderstorms. Even if storms do not track directly overhead any terminals, strong gusty winds of 30 to 40 knots cannot be ruled out at times from nearby convection. Showers and storms will dissipate around 02Z-03Z Thursday with all terminals seeing lighter winds and dry conditions to end the TAF period. Mountain top obscuration may be possible at times Wednesday, especially across western portions of the state where showers and thunderstorms will be more likely.

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

RIW WATCHES/WARNINGS/ADVISORIES

None.