textproduct: Western and Central Wyoming

KEY MESSAGES

- Today is another day of seasonable temperatures with isolated to scattered showers and thunderstorms during the afternoon and evening. A few strong to severe storms cannot be ruled out, with the main concerns being frequent lightning, strong wind gusts around 50 mph, pea-to dime-sized hail, and brief heavy rain. Showers are expected to linger overnight from west-central WY eastward toward eastern WY.

- Wednesday will see another round of afternoon and evening showers and thunderstorms with near seasonable temperatures. Strong storms are possible over Johnson County late Wednesday afternoon. Showers will again linger Wednesday night into Thursday morning over some areas.

- Isolated showers and thunderstorms are possible again Thursday afternoon over central WY, and perhaps Friday afternoon across western WY. Temperatures begin to climb on Friday to 5-10 degrees above normal.

- Very warm to hot temperatures are expected this weekend along with dry conditions. Record-breaking temperatures are possible Saturday, Sunday, and Monday, with mid 90s in the western valleys, and 100 to 105 degrees in the basins east of the divide.

DISCUSSION

Issued at 328 AM MDT Tue Jul 7 2026

A few showers and thunderstorms continue to linger across the state early this morning. As of writing this around 0100 MDT, a couple flashes of lightning have been detected over portions of western WY. However, convective activity is gradually waning with clusters of lightning continuing to decrease. Precipitation chances will remain mostly across western and northern WY through the predawn hours. Showers and storms will continue to trek east through the morning with the bulk dissipating by sunrise.

A shortwave will be the main instigator for the "active" weather today and Wednesday. The shortwave currently is making its way across Montana while ushering in above normal moisture to the region. This can be seen with PWATs being nearly 100-150% above normal across much of the area. Dewpoints also reflect this with portions of the Bighorn Basin and Johnson County likely to see values in the 50s this afternoon. As for temperatures, they will be similar to Monday with highs in the upper 80s to low 90s east of the Divide and low to mid 80s west of the Divide. Scattered showers and thunderstorms will once again be possible later this afternoon and evening. Coverage today will shift farther south with northwestern WY likely having lesser chances of seeing a shower or storm compared to elsewhere. Precipitation chances across the forecast area aside from northwestern WY look to range from 20-40% with the best chances being over central and portions of southern WY.

The other aspect regarding the convection possible this afternoon and evening, will be the potential for a few strong to severe storms developing. The Storm Prediction Center has highlighted much of the state with a marginal risk (1 out of 5). The only exception to this is portions of northwestern and western WY, specifically much of YNP and the Tetons/Jackson Hole where the marginal risk has been excluded. There is a very small sliver of slight risk (2 out of 5) for a portion of Johnson County mainly due to large hail threat. The setup is a wide swath of above normal moisture across the area. Morning cloud cover is expected to gradually clear by the early afternoon with daytime heating helping produce CAPE values around 500 J/kg over much of the state. Some CAMs are highlighting portions of Johnson County and central WY with swaths of CAPE nearing 1000 J/kg. So if this were to occur, there could be more juice for any storms that develop. Steep low to mid level lapse rates are forecast over much of the state as well. The other factor will be favorable dynamics as a result of the nearby short wave. Low to mid level wind shear values currently look to range from 25 to 35 knots. Overall, the main threat today will be strong gusty winds with CAMs highlighting favorable Downdraft CAPE values. Storms could produce strong gusty outflow winds of 50 mph or more at times. There does remain a threat for hail with the most favorable locations being central and northern WY, specifically Johnson County. Otherwise, frequent lightning and brief moderate rainfall may be possible with any storms. Showers and thunderstorms may linger into the late evening hours Tuesday and possibly into the early morning hours Wednesday.

Wednesday has trended towards another day with possible afternoon showers and thunderstorms. This once again is the result of lingering moisture and the exiting shortwave. Currently, much of the state looks to have similar chances for precipitation as Tuesday. However, chances for strong to severe storms looks to diminish and shift farther east. The SPC currently has far eastern portions of Johnson and Natrona Counties in a marginal risk with the main concerns being strong gusty winds and hail. Aside from these locations, the remainder of the state will see similar hazards as the previous days with frequent lightning, gusty winds, and small hail possible.

No, there does not seem to have been a technical glitch in the long term forecast models, it really is looking to be that hot this weekend. Some long term models have done a good job of indicating this heat as early as last week. Barring some miraculous shift in the weather pattern, we are likely to see a period of dangerously hot, record breaking temperatures this weekend. This heat will be the result of an anomalously potent high pressure ridge that builds across the western/central CONUS. Temperatures start to turn up Friday with current highs getting into the mid to upper 90s east of the Divide and upper 80s to low 90s west of the Divide. The warmest temperatures look to arrive for the weekend. Guidance is showing western valleys such as Star Valley and Jackson Hole possibly seeing highs around 95F Saturday. Locations east of the Divide to no surprise are warmer, with central basins seeing highs nearing the century mark. Northern locations, such as portions of the Bighorn Basin may see highs nearing 105F. Sunday looks even warmer with locations west of the Divide seeing 20-40% of highs nearing 100F. East of the Divide central basins have 20-50% for highs around 105F. Portions of the Bighorn Basin may see highs near 110F with chances sitting around 10-30%. These percentages are to show the potential range for high temperatures. So if there is a 20-50% for highs near 105F, its likely the highs will at least be greater than 100F. There is increasing likelihood that numerous daily high temperature records and even all-time high temperature records may be met or broken. Climate data at KLND goes back to 1891 and the current all time high temperature is 102F set back in 1935 on July 27th. Currently, the NBM has a forecast high of 104F for Sunday, so that should give an idea of how historic this period of heat may be. Yes, this degree of heat can be dangerous for those who are at risk or do not use caution. So be sure to stay up to date on the forecast and be prepared, especially if planning outdoor activities!

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 1153 AM MDT Tue Jul 7 2026

Shortwave across central Montana is drawing moisture northeast from the Great Basin into Wyoming late Tuesday morning. Abundant morning sunshine is allowing for convection to already ignite within this moisture plume. Scattered showers and thunderstorms develop between 18Z-20Z/Tuesday and track northeast through the forecast area. All terminals have PROB30 chances with gusty wind 25-40kts the primary hazard. However, higher dew points today will also favor some brief downpours, so less than 30-minute periods of MVFR visibility cannot be ruled out. Convection wanes in coverage and intensity between 03Z- 06Z/Wednesday, but enough moisture will be present to keep isolated showers ongoing overnight. By 15Z/Wednesday, cloud cover clears the region. All terminals to be VFR through the period with the possible exception of the aforementioned short-term MVFR.

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.