textproduct: Pocatello

KEY MESSAGES

- Mid-to-Late Week Heat Surge: Temperatures will steadily rise, reaching the low-to-upper 90s across lower valleys Thursday and Friday. Heat advisories are in effect for Thursday and Friday.

- Monsoon Moisture Returns: Models show a high pressure ridge shifting east with an approaching low system, which will bring moisture from our south back into the area. Wetter and cooler conditions will return for the weekend into next week.

- Increased Fire Danger Saturday: Models show scattered thunderstorm coverage, which will increase fire danger across the area.

DISCUSSION

Issued at 203 PM MDT Wed Aug 19 2026

Dry conditions are in store through tomorrow as high pressure builds over the region, allowing us to warm back into above-normal territory through Friday. HEAT ADVISORIES are in effect for many valley locations as widespread temperatures in the advised areas will range 93 to 98 degrees, with some even reaching triple digits as the ridge axis shifts directly overhead. Models continue to show an upper low setting up along the PacNW coast and thus shifting the ridge eastward this weekend. This will open up the door for the return of monsoon moisture. The ECMWF ensemble indicates precipitation as early as Thursday evening while the GFS ensemble has trended a bit earlier with the introduction of accumulating precipitation late Thursday/overnight into Friday morning. While isolated activity is anticipated on Friday, Saturday still looks to be the busiest weather day for Southeast Idaho with scattered thunderstorms for portions of the region. Storm activity will trend isolated again heading into the later weekend, although the active pattern will continue into at least the first part of the next week as low pressure remains off the coast with an area of high pressure set up over the Southwest.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 1127 AM MDT Wed Aug 19 2026

VFR conditions with generally light winds under high pressure. No major changes to forecast aside from slight wind adjustments.

FIRE WEATHER

Issued at 203 PM MDT Wed Aug 19 2026

High pressure is overhead today and leading to dry conditions and warming temperatures. No showers or storms are expected this afternoon. Min HRs are ranging from about 15 to 20 percent today and winds remain on the lighter side, gusting to around 20 mph. Over the next few days, our high pressure ridge will be pushed just slightly eastward as an area of low pressure moves into the area just off the coast of the PNW. This is poised to allow some monsoon moisture to works its way back into Eastern Idaho as early as tomorrow afternoon, though the potential for isolated storms Thursday afternoon remains quite low, generally less than 15 percent. Activity begins to increase on Friday, but still looks to be mostly isolated. It's as we get into the weekend that storms become more scattered, so Saturday looks like the next best day for any Red Flag Warning potential, and perhaps Sunday, but activity will become a bit more isolated for some in the second half of the weekend. We won't totally dry out as we head into next week. In fact, isolated storm chances continue through at least the first half of next week.

PIH WATCHES/WARNINGS/ADVISORIES

Heat Advisory from noon to 10 PM MDT Thursday for IDZ051- 054>057-075. Heat Advisory from noon to 10 PM MDT Friday for IDZ051>059-075.