textproduct: Pocatello

KEY MESSAGES

- Continued above normal temperatures for afternoon highs.

- Afternoon and evening showers and thunderstorms continue through at least Wednesday now.

- Marginal risk of severe thunderstorms for portions of Custer, Lemhi, Butte, and Clark counties today and this evening.

DISCUSSION

Issued at 159 AM MDT Sun Jul 5 2026

Sun through Tue night...SPC has placed large portions of Custer and Lemhi counties in a marginal risk for severe thunderstorms, while some thin slivers in northern Butte and western Clark counties are in the same boat. Afternoon/evening showers and thunderstorms continue through this early period, though the other days are not expected to have a severe threat at this time. Temperatures peak today during this period as the better infiltration of clouds due to a trough moving through the mean southwest upper level flow for later days takes the edge off the heating. None of these small troughs have the power to generate heavy precipitation.

Wind in the afternoon starts increasing to the point where it will be breezy for Mon and Tue.

Wed through Sat...Strongest wind of the week is Wed and Thu afternoons, but it stays elevated through the rest of the week. G30KT very possible for Wed and Thu.

Starting Thu, the risk of thunderstorms drops significantly as the upper flow becomes less southerly and more westerly. While the first batch of air moving in provides some cooling due to an air mass change, it quickly heats up, to where by the weekend many locations will be reaching the upper 90s at lower elevations.

AVIATION /12Z TAFS THROUGH 12Z MONDAY/

Issued at 523 AM MDT Sun Jul 5 2026

Difficult forecast at this time. NBM has little threat at any airdrome except KDIJ for TSRA, and time-heights show little moisture below 600mb to work with. However, SPC has put KSUN, KIDA, and KDIJ in the TS area on its charts. Very torn here, but only kept the PROB30 group in for this afternoon at KDIJ. Don't see much in wind outside of the PROB30 group. Satellite is clear at this time, which would lead to an even more optimistic outlook, as the NAM already has CIGs around 500mb. So the NAM is not verifying well. Very much a low confidence forecast.

FIRE WEATHER

Issued at 159 AM MDT Sun Jul 5 2026

Incredibly unstable air develops with afternoon heating, with mixing height in the southern areas exceeding 20,000ft MSL. Couple this with dry conditions at 700mb and should a fire get established, expect high intensity fuel driven wildfire. Fortunately, wind is not expected to be strong today. The mixing height and instability drops off for Mon and Tue, but it doesn't stop the likelihood of afternoon and evening showers and thunderstorms. The strong instability today has triggered a marginal risk of severe thunderstorms by the Storm Prediction Center for today over the Salmon-Challis NF and western portions of the Targhee NF.

Wind gets stronger Tue and by Wed and Thu, gusts hitting at least near 30 mph are likely.

This leads to what is the humidity doing. Widespread critical afternoon humidity values have already expected today with all but the central Idaho mountains and the Targhee NF having minimum humidity forecasted below 15 percent. As some moisture moving in with an upper level low slides into southern Idaho, the humidity is expected to be up, but still some pockets of below 15 percent continue. The area of low humidity shifts around for the next couple of days after that, including Wed and Thu. Both days appear ripe for Red Flag conditions in the southern fire weather forecast zones if the fuels are receptive.

PIH WATCHES/WARNINGS/ADVISORIES

None.