textproduct: Pocatello

KEY MESSAGES

- Prolonged Quiet Weather Period: High pressure and dry air will keep eastern Idaho completely dry with minimal cloud cover through the workweek, upcoming weekend, and into early October. Zonal flow aloft will hold daytime highs near late- September averages in the upper 60s to lower 70s across lower elevations through Wednesday.

- Unseasonable Late-Week Warmth: An amplifying Great Basin ridge will boost lower-elevation temperatures into the upper 70s and lower 80s starting Thursday and continuing through the weekend.

- No Fall-Like Weather in Sight: High confidence exists for above-normal temperatures and suppressed precipitation extending through the first full week of October.

DISCUSSION

Issued at 100 PM MDT Tue Sep 29 2026

Afternoon satellite imagery displays mostly clear skies with only a few stray cirrus clouds drifting across the region. A broad, tranquil weather pattern is firmly established, marking the beginning of a prolonged period of quiet weather across eastern Idaho. Predominantly zonal upper-level flow over the next couple of days will maintain light surface winds and hold daytime maximum temperatures right around seasonal climatological norms. Lower-elevation valleys will top out in the upper 60s to lower 70s through Wednesday, accompanied by clear, crisp overnight lows in the upper 30s to upper 40s.

A transition toward unseasonable warmth develops during the second half of the workweek. Operational models and ensemble guidance agree that an upper-level ridge anchored over the southern Great Basin will amplify northward across the Intermountain West on Thursday. Strong subsidence and rising 500 mb heights will drive daytime highs 5 to 10 degrees above seasonal averages. Valley locations across the Snake Plain and Magic Valley will widespread reach the upper 70s to lower 80s starting Thursday, with similar warm readings persisting right through the weekend.

High confidence continues for this ridge-dominated regime to remain locked in place through the first few days of October and likely into the first full week of the month. Ensemble clusters show no indication of any troughs or cold fronts capable of breaking down the ridge. Consequently, dry conditions and above- normal temperatures will prevail across the region, with no true fall-like weather or widespread precipitation expected anytime soon.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 1122 AM MDT Tue Sep 29 2026

With high pressure building in over the area, no weather impacts are expected at our TAF sites today or tonight. Little to no cloud cover persists throughout the period with winds around 15 kts at BYI, PIH and IDA. Winds remain a bit more elevated than usual overnight near BYI, but elsewhere they should be light and variable overnight. No precipitation is expected through the rest of this week.

FIRE WEATHER

Issued at 100 PM MDT Tue Sep 29 2026

High pressure is building in over the area and will allow us to warm up and dry out for the rest of the week. Winds will still be a bit breezy at times today and tomorrow with gusts around 20 to 25 mph, especially in the eastern Magic Valley and South Hills. Temperatures continue to warm through the week and eventually highs in the lower elevations will push towards 80 degrees, running about 10 degrees above our climatological normals for this time of year which are generally in the upper 60s and low 70s. Each afternoon, min RHs will range from 20 to 35 percent. Both the 6 to 10 and 8 to 14 day outlooks continue to show a high probability of continued above normal temperatures and below normal precipitation through the first two weeks of October.

PIH WATCHES/WARNINGS/ADVISORIES

None.