textproduct: Pocatello

KEY MESSAGES

- Flash Flood Watch for Wapiti Burn Scar: A localized Flash Flood Watch is in effect for the Wapiti burn scar near Stanley. Repeated rounds of showers and thunderstorms over the Central Mountains today could trigger rapid runoff and debris flows in the burn area.

- Breezy but Weaker Winds Today: Winds will remain breezy this afternoon across the Snake Plain and Magic Valley, but peak gusts are expected to be slightly weaker than what was observed on Wednesday.

- Brief Warming Trend Through Saturday: Daytime temperatures will warm slightly each day through Saturday, briefly returning lower-elevation highs to the upper 70s and lower 80s.

- Major Pattern Shift for Labor Day: High confidence remains for a potent Pacific storm system to arrive late in the holiday weekend. Expect widespread wetting rains and a 10 to 15-degree drop in temperatures from Sunday into Labor Day.

DISCUSSION

Issued at 234 AM MDT Thu Sep 3 2026

The broad upper-level trough over the Pacific Northwest continues to govern our weather pattern. Moisture streaming into the region remains focused primarily across the Central Mountains. High-resolution convective-allowing models (CAMs) continue to indicate multiple rounds of showers and embedded thunderstorms traversing the higher terrain today. Given the convective nature of the precipitation and the potential for brief, heavy downpours, a localized Flash Flood Watch has been issued for the Wapiti burn scar near Stanley. Hydrophobic soils within the burn perimeter make this area highly susceptible to rapid runoff and debris flows, even with modest rainfall rates.

Elsewhere across eastern Idaho, conditions will remain largely dry. Winds across the Snake Plain, Magic Valley, and Arco Desert will remain breezy out of the west-southwest this afternoon, but peak gusts are expected to be a few notches lower than Wednesday's near-advisory levels. High temperatures today will remain cooler than normal, holding in the 60s and 70s but a few degrees warmer across the Snake Plain and Magic Valley compared to yesterday.

As the initial waves of energy lift out of the region, we will see a brief reprieve on Friday and Saturday. Precipitation coverage will wane, and a subtle warming trend will take hold. Expect afternoon maximum temperatures to increase slightly each day, pushing lower-elevation valleys back into the upper 70s and lower 80s by Saturday afternoon. Breezy afternoon winds will persist, but overall weather impacts will be minimal ahead of our next major system.

Confidence continues to increase regarding a significant pattern shift for the latter half of the holiday weekend. Global model ensembles are in excellent agreement that the parent upper-level low anchored off the Pacific Northwest coast will finally eject eastward, digging directly into the Intermountain West on Sunday and Monday. This system will bring a surge of strong atmospheric lift and deep moisture, resulting in high probabilities for widespread wetting rains across all of eastern Idaho. Still some uncertainty with respect to precip amounts, which have trended back down, but high confidence in below normal temps on the Labor Day holiday with many locations likely staying in the 60s.

AVIATION /06Z TAFS THROUGH 06Z FRIDAY/

Issued at 929 PM MDT Wed Sep 2 2026

Winds have diminished this evening and will remain light into Thursday morning. Virga will move through the region tonight but not expecting anything more than high vfr ceilings. SUN has an outside shot of seeing a stray shower although the better chances for rain are further north. Winds will increase most notably at PIH and DIJ tomorrow afternoon.

FIRE WEATHER

Issued at 234 AM MDT Thu Sep 3 2026

Precipitation focus now shifts to the Central Mountains, where repeated rounds of showers and thunderstorms today pose a localized flash flood and debris flow risk, specifically over the Wapiti burn scar. Breezy west-southwest winds will continue across the Snake Plain and Magic Valley today and Friday, but minimum relative humidity values will get close, but stay above critical thresholds. A low pressure system in the latter part of the holiday weekend looks to bring cooler temps and precip to the region although just how much precip remains the forecast challenge. A drying trend looks likely beyond the Labor Day holiday with a slow up-tick in temperatures.

PIH WATCHES/WARNINGS/ADVISORIES

None.