textproduct: Pocatello

KEY MESSAGES

- Mountain Showers and Lower-Elevation Warmth (TodaySaturday): Broad cyclonic flow around a Washington low will keep showers and thunderstorms active over the Central Mountains for the next 36 hours. Elsewhere, dry conditions will prevail as valley highs climb into the 80s.

- Breezy Sunday Ahead of Main System: Southerly winds will increase on Sunday, pushing temperatures into the 80s under increasing clouds, with widespread rain holding off until late Sunday evening.

- Widespread Labor Day Rain and Brief Cooldown (Late SundayMonday): As the upper low shifts east, widespread rain (0.25" to 0.50" average QPF) will overspread eastern Idaho late Sunday into Monday, dropping high temperatures into the 60s and lower 70s.

- Quick Mid-Week Warming Trend: Precipitation wanes late Monday as the system exits into Alberta, paving the way for a rapid warm-up back into the 80s by Wednesday as high pressure rebuilds over the Southwest.

DISCUSSION

Issued at 319 AM MDT Fri Sep 4 2026

Eastern Idaho remains positioned along the eastern periphery of a broad, persistent upper-level low centered over western Washington. Southwest-to-westerly cyclonic flow around this system will continue streaming waves of shortwave energy over the Central Mountains, maintaining shower and thunderstorm chances over the next 36 hours. Outside of the central mountain terrain, dry conditions and variable mid-to-high level cloud cover will prevail. Daytime maximum temperatures will climb back to near 80 degrees across the lower Snake Plain and areas toward the Utah border today, expanding into widespread 80s across the Snake Plain and Magic Valley on Saturday. Mountain precipitation will briefly wane Saturday afternoon as the parent low begins a slow eastward translation across the Pacific Northwest.

Temperatures will continue their upward trend on Sunday as southerly flow strengthens ahead of the approaching trough, boosting valley highs into the 80s amidst breezy afternoon winds. Increased cloud shading and widespread precipitation will hold off through most of the day, preserving favorable outdoor conditions until late Sunday evening. Moisture and dynamic lift increase sharply Sunday night through Labor Day Monday as the trough axis crosses Idaho. Operational models and ensemble guidance display ongoing spread regarding QPF totals: the ECMWF maintains a wetter solution compared to the drier GFS. A middle- of-the-road consensus blend remains in place, forecasting roughly 0.25" to 0.50" of wetting rain across much of eastern Idaho, though these totals remain subject to adjustment as guidance converges. Extensive cloud cover and rain will cap Monday highs in the 60s to lower 70s. As the core low lifts into Alberta late Monday afternoon, precipitation will diminish from west to east alongside clearing skies.

Conditions dry out rapidly on Tuesday as temperatures begin a fast recovery under rising 500 mb heights. Global ensembles show high-pressure ridging attempting to rebuild across the Southwestern U.S. mid-to-late week, positioning eastern Idaho along the northern margin of the ridge axis. Model guidance displays noticeable spread regarding how aggressively the ridge amplifies, but lower elevations are forecast to return to the lower 80s as early as Wednesday, with potential to trend even warmer if the ridge axis shifts further north. Southwest flow aloft along the ridge periphery will keep low-end, daily precipitation chances in the forecast for higher terrain zones through late week.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 919 PM MDT Thu Sep 3 2026

Expect a relatively brief period of gusty winds overnight as a low pressure system moves north through the region. Those winds should weaken this morning. Some showers may approach SUN over late tonight into Thursday but expect VFR conditions.

FIRE WEATHER

Issued at 319 AM MDT Fri Sep 4 2026

Convective activity over the next 36 hours will remain largely restricted to the Central Mountains, while lower elevation zones experience warm, dry conditions with highs in the 80s. Increasing southerly winds on Sunday will precede a strong atmospheric moisture surge Sunday night into Labor Day Monday, delivering widespread wetting rains (0.25"0.50" QPF) and excellent relative humidity recoveries across all dispatch zones. Drier, significantly warmer conditions return mid-week.

PIH WATCHES/WARNINGS/ADVISORIES

None.