textproduct: Pocatello

KEY MESSAGES

- Scattered thunderstorms return to all of southern Idaho. Thunderstorms continue through the next seven days for many locations in southern Idaho.

- Red Flag Warnings in place for scattered thunderstorms today for all of Central Idaho Dispatch area, Southern Idaho Dispatch area, and portions of the Eastern Idaho Dispatch area.

- After record heat the past two days, clouds and precipitation will cool afternoon highs significantly today, then continue a weak overall cooling trend through Friday.

DISCUSSION

Issued at 211 AM MDT Sat Aug 22 2026

Long wave ridge will allow a weak shortwave to move through the mean southwest flow over the Gem State. This will enhance the thunderstorm activity in the already moist and unstable air over the forecast area. SPC has put nearly the entire forecast area in a marginal threat of severe thunderstorms (except a small wedge in Bear Lake County at the border with Utah. Thunderstorm threat is as high as 40 percent in the southern and eastern highlands. Could easily get G50KT for thunderstorm outflow.

The increased moisture will mean more clouds and rainfall can cause evaporative cooling to bring the record temperatures of Thu and Fri down some 3 to 8 deg F. The cooling continues into Sun and Mon, but at a slower rate, with temperatures still in the upper 80s to around 90 on Sun and Mon. Overnight lows continue mild with the cloud cover.

Wind stays weak today, but Sun will see 14 to 24 mph wind in the central Idaho mountains and the northwest side of the Snake River plain. Wind of this strength does not show up again until perhaps Thu.

For other items in the extended (Tue through Fri), the strong upper level ridge is finally beaten down in some of the clusters on either Thu or Fri, but still only affects the forecast area in about 53 percent of the solutions. Upper level flow appears more southwest than south, which should cut down significantly on thunderstorm coverage during the extended period.

AVIATION /06Z TAFS THROUGH 06Z SUNDAY/

Issued at 945 PM MDT Fri Aug 21 2026

Quite a bit of mostly showers with isolated thunderstorms working up from the south. A rogue gust to 30kts is possible overnight, but probably not very likely. Convection should clear around 12z with next round of storms expected during the afternoon.

FIRE WEATHER

Issued at 211 AM MDT Sat Aug 22 2026

An influx of moist and unstable air, including the possibilities of outflow from a thunderstorm hitting 58+mph, will reach nearly everywhere in the Fire Weather Forecast area. Coverage of thunderstorms this afternoon and evening peaks at 25 percent to 45 percent, so Red Flag Warnings were issued yesterday for abundant lightning. Thunderstorm coverage lowers considerably for Sun, but then may be up again on Mon.

Fortunately, the moist air is pushing humidity readings up. Most readings will stay well above the 15 percent threshold for critical fire weather criterion. Cloud cover helps, as the high temperatures that lately have been setting records will be solidly cooler. The cooling and more humid trend continues through Mon. One offset to this is that the cloud cover will keep temperatures warmer at night, so recovery may not be as good, unless some wetting rains occur.

Wind will be up on Sun, mainly over the central Idaho mountains and the Snake River plain/eastern Magic Valley. It should be enough to meet critical fire weather speeds, but the humidity should be too high for any sort of critical fire weather situation. More wind develops Thu afternoon, but temperatures should be even cooler than this weekend, which bodes will for humidity readings.

PIH WATCHES/WARNINGS/ADVISORIES

Red Flag Warning from noon today to 9 PM MDT this evening for IDZ410-422-425-427-475-476.