textproduct: Western and Central Wyoming

KEY MESSAGES

- Seasonably warm today with the chance (20 to 40 percent) for showers and storms across the western 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.

UPDATE

Issued at 1224 PM MDT Wed Jul 1 2026

The main change with this update was increasing precipitation chances across western and northern Wyoming mid-afternoon through this evening, more inline with the increased coverage that the latest hi-res models are depicting. Any shower or storm could produce gusty outflow winds up to 60 mph today, though near 40 mph would be most likely. Any lingering convection should end between 6pm and midnight. Looking ahead to the holiday weekend, it still looks like it will be warm and dry with no major weather system.

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 be 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 Bighorn 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 /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 1125 AM MDT Wed Jul 1 2026

Mostly clear skies this morning will become partly cloudy to mostly cloudy this afternoon and evening, primarily over western and northwest WY. Another disturbance from the Great Basin is moving northeastward today, bringing a chance of showers and thunderstorms to some of the TAF sites. Best chances appear to be KJAC and KCOD, from about 01/20-02/01Z. Gusty outflow winds over 40 kts with brief rain and lightning are the primary hazards. Wind gusts over 50 kts are possible across far NW WY this afternoon due to strong outflow from thunderstorms. KBPI/KPNA/KWRL also have a mention of TS, but confidence is not as high at these locations. Otherwise, breezy and gusty southwest winds are expected at the other sites. However, outflow from the afternoon/evening storms is expected to push eastward during the evening and likely bring 20-30 kt gusts to KRKS/KLND/KRIW/KCPR though no precipitation is expected. The higher terrain and northern WY should see lingering showers through 02/06Z with winds decreasing after midnight.

Overall, VFR conditions are generally expected, though MVFR conditions are slightly possible if a thunderstorms happens to pass over a TAF site. The higher terrain across northwest WY will be partially obscured at times.

Thursday looks to be a repeat of Wednesday, with southwest winds picking up before 02/18Z at most TAF sites. Western and northwest WY showers and thunderstorms should develop by 02/20Z, though KJAC/KBPI/KPNA/KCOD/KWRL have better chances of storms during the afternoon. Outflow winds of 20-30 kts will then impact the other sites during the early evening hours.

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.