textproduct: Pocatello

KEY MESSAGES

- Weak Brushing Shortwave TonightEarly Tuesday: An upper- level shortwave passing along the Canadian border will increase mid-to-high clouds tonight, with a slight chance of an isolated light shower or mountain flurry in the Central Mountains and near Island Park.

- Unseasonably Mild Mid-Week Stretch (WednesdayFriday): A building Great Basin ridge will ensure dry conditions and sunny skies, pushing daytime highs 7 to 12 degrees above normal (upper 50s to lower 60s across lower elevations).

- Increasing Weekend Winds: The regional pressure gradient will tighten over the weekend ahead of an approaching Pacific low, generating breezy conditions while mild temperatures hold through Sunday.

- Pattern Change Likely Early Next Week: A strong cold front and Pacific moisture tap will arrive late Sunday night into Monday, dropping temperatures 10 to 15 degrees and delivering scattered to widespread rain and snow chances early next week.

DISCUSSION

Issued at 139 AM MST Mon Nov 9 2026

The weather pattern across eastern Idaho will remain generally benign through the workweek, characterized by an absence of high-impact systems and continued above-normal temperatures. Weak upper-level ridging over the area will slowly recede today as an upper-level shortwave digs into the Pacific Northwest and tracks eastward along the US/Canada border. Moisture with this system is very limited, though high-resolution convective- allowing models (CAMs) indicate a low-to-moderate potential to squeeze out an isolated light shower or mountain flurry across the Central Mountains and near Island Park late this evening through early Tuesday morning. The primary impact will be an increase in mid-to-high level cloud cover regionwide. As the shortwave advances into the Northern Plains on Tuesday, skies will rapidly clear from west to east.

Skies will remain mostly clear as high pressure rebuilds and centers over the Northern Great Basin from Wednesday through Friday. Strong subsidence and rising heights will promote unseasonably warm afternoons, with daytime highs running 7 to 12 degrees above seasonal averages. Valley locations across the Snake River Plain and Magic Valley will reach the upper 50s to lower 60s under light winds, making for very pleasant late- autumn conditions.

The synoptic pattern begins to break down over the weekend as an upper-level trough over the Gulf of Alaska taps into Pacific moisture and ejects energy into the Pacific Northwest. While deep moisture will take time to reach eastern Idaho, the regional pressure gradient will tighten over the weekend, resulting in increasingly breezy surface winds alongside thickening cloud cover. Unseasonably mild temperatures will hold through Sunday afternoon ahead of the front. The primary moisture plume and associated cold front are progged to arrive late Sunday night into Monday. A sharp 500 mb height drop will drive a 10 to 15-degree temperature plunge for early next week, accompanied by scattered to widespread rain and snow showers. While timing details will be refined as the system approaches, quiet conditions will prevail across the area until then.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 350 AM MST Mon Nov 9 2026

VFR conditions are expected through the period. Mid and upper level clouds coming through the area will continue through the evening because of a weak shortwave feature moving north of the region. Not expecting any precip with this feature. Very weak high pressure will build in tonight into tomorrow morning. Winds are expected to remain light through much of the day with maybe a slight increase up to 7 to 10 kts for PIH, IDA, and DIJ later this evening and overnight.

PIH WATCHES/WARNINGS/ADVISORIES

None.