textproduct: Pocatello

KEY MESSAGES

- Marginal Severe Risk Area-Wide Today: Nearly all of eastern Idaho remains under a Marginal Risk for severe thunderstorms today, while the Slight Risk zone has shifted south into Northern Utah. Strong shear will remain capable of producing isolated damaging wind gusts and small hail within stronger cells.

- Showers Persist Into Early Sunday: High-resolution model guidance keeps shower and thunderstorm activity around throughout the day today and through the first half of Sunday morning before rapid clearing takes hold Sunday afternoon.

- Slight Warming Trend Next Week: Daytime high temperatures next week have been adjusted slightly upward compared to previous forecasts, returning lower-elevation values closer to seasonal averages in the upper 70s and 80s.

DISCUSSION

Issued at 258 AM MDT Sat Aug 29 2026

Eastern Idaho remains positioned under broad southwesterly flow between an upper-level low moving through the Pacific Northwest and high pressure anchored over the South-Central U.S. The latest convective outlook update has shifted the Slight Risk area south into Northern Utah, where low-level moisture and instability are most favorably aligned. However, nearly all of eastern Idaho remains under a Marginal Risk today. Effective bulk shear values exceeding 40 knots will remain sufficient to organize terrain-forced convection, making localized severe downburst winds (50-60+ mph) and small hail the main threats with stronger cores.

High-resolution convective-allowing models (CAMs) are in strong agreement that shower and thunderstorm coverage will persist throughout the day today and linger through tonight. Unlike typical diurnal events that collapse quickly after sunset, elevated moisture and synoptic lift will keep precipitation active into the early morning hours of Sunday.

As the primary upper trough axis pivots eastward across northern Montana and southern Alberta on Sunday, drier air will shunt into the region from the west. Showers and cloud cover will linger through Sunday morning, particularly over the Eastern Highlands, before a steady clearing trend takes hold from west to east during the afternoon hours. Temperatures on Sunday will remain on the cool side of average, holding in the upper 60s and 70s across most valley locations.

A transitional pattern takes shape for the new workweek as weak ridging attempts to build into the Great Basin. Forecast guidance has nudged daytime temperatures slightly upward compared to yesterday's model runs, pushing lower-elevation highs back into the upper 70s to lower 80s through the week. However, operational models and ensemble clusters continue to exhibit significant spread regarding the long-range upper-level pattern. Guidance is struggling to resolve how quickly secondary shortwave energy moving out of the Gulf of Alaska will flatten the ridge or re-establish broad Pacific Northwest troughing. Given this variance, a consensus blend remains the preferred forecast approach, keeping low-end, isolated afternoon mountain storm chances and near-normal temperatures in place through the second half of next week.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 618 AM MDT Sat Aug 29 2026

Will continue to see showers and thunderstorms across the region through Saturday evening with precip gradually tapering off from west to east as we move into the early morning hours on Sunday. Maintained PROB30 groups for later this afternoon to account for TSTM and gusty wind potential. CIGs should remain at VFR levels through the period despite the storms around the area.

FIRE WEATHER

Issued at 258 AM MDT Sat Aug 29 2026

Extensive cloud cover, surging relative humidity, and widespread precipitation will keep fire weather concerns heavily suppressed through Sunday morning. While lightning frequency will remain elevated with passing convective cores today and tonight, rain efficiency will keep most storms wet. Gusty and erratic outflow winds up to 45 mph remain the main operational hazard with stronger cells today. Clearing conditions Sunday afternoon will lead into a slight warming trend next week, though relative humidity values will remain at or above critical thresholds.

PIH WATCHES/WARNINGS/ADVISORIES

None.