textproduct: Western and Central Wyoming

KEY MESSAGES

- Seasonably warm today with isolated to widely scattered afternoon showers and storms (a 1 in 5 to 1 in 3 chance) across the northwestern half of the area.

- Elevated fire weather concerns for the next few days, with Friday looking like the day of greatest concern with the breeziest conditions expected.

- Above normal temperatures return this weekend and continue into early next week.

DISCUSSION

Issued at 138 AM MDT Wed Jul 1 2026

Welcome to the warmest month of the year, AKA julio (Spanish), julho (Portuguese), juillet (French) or as it is called in English, July. And, it will definitely feel like the middle of summer, especially as we head toward the end of the forecast period.

Wyoming continues to be in the transition zone between a trough over the western United States and the death ridge over the eastern United States that will bringing a heat wave to that neck of the woods. But we care about Wyoming, not the east. Today looks like a fairly typical summer day with near normal temperatures. A weak shortwave will be moving over the top of the ridge, and this will bring some showers and thunderstorms this afternoon to the northwestern portions of the area (from a 1 in 5 chance to a 1 in 3 chance). There is some instability but not the most (CAPE values as high as 500 J/Kg, lifted indices to minus 3). If there is a chance of stronger storm today, it would be across Yellowstone Park where the air is the most unstable. Moisture is lacking though, with precipitable water values below seasonal normals for most locations, especially East of the Divide. The main threat from any thunderstorm or even shower could be strong wind gusts, given the large dew point depressions. Little to no convection is expected in the southeastern half of the area. Humidity will be quite low East of the Divide (under 15 percent in many locations), but with wind light to moderate fire weather conditions should remain below critical. Any showers and storms should end by around midnight.

Tomorrow looks fairly similar to today with near normal temperatures and a similar probability of precipitation in the same locations with another shortwave passage. Humidity looks similar as well for most. It could be a bit breezier, but no high wind is expected at this time. The one exception may be Johnson County and possibly the Big Horn Basin where some increased moisture may bring a locally stronger storm (eastern Johnson County has a marginal risk). The directional shear is more vigorous here but the best chance of a stronger storm would be east of the County Warning Area across eastern Wyoming.

The trough will get filled in by Friday and flow will turn from southwesterly to zonal. With the area still near the top of the ridge, another shortwave will move in from the west with another chance of convection, only this time the best chance of storms would shift mainly to northern Wyoming with diminishing chances further south. Through this period, temperatures should be warm but not hot, generally near normal for most of the area. One concern though, this could be the breeziest day of the next three and conditions with humidity remaining rather low East of the Divide, we may have to think about near critical to possibly critical fire weather across the wind prone portions of the area.

Following that, ridging then rebuilds across the west starting this weekend and continuing into next week. Flow will turn to the southwest once again and this means hot temperatures with many locations East of the Divide seeing highs into the 90s. Higher heights and temperatures aloft should also begin to limit chances of convection. Saturday may end up being a completely dry day across the area. For the rest of the period, Wyoming will still be close enough to the top of the ridge for some chances of convection each afternoon, mainly across the northern half of the state and especially near the mountains. It is still difficult to pinpoint a more active day this far out though.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 417 AM MDT Wed Jul 1 2026

Largely VFR conditions are expected through the TAF period. A bit of breeze will occur this afternoon but most gusts should remain around 20 knots at the most. There will be another round of isolated to scattered thunderstorms today (around 20 to 30 percent chance) across roughly the northwestern half of the area. The most impacted areas will be in vicinity of KJAC, KCOD, KPNA, KBPI and KWRL. We have elected to go with PROB30 groups given the difficulty in pinpointing the storms. We can't rule out a storm at KRKS, KRIW and KLND but with the chance less than 15 percent we left it out of the forecast. Occasional mountain obscurations may occur in the western mountains where there is higher likelihood of convection. And convection should end by 04Z Thursday with dry conditions through the rest of Wednesday night.

RIW WATCHES/WARNINGS/ADVISORIES

None.