textproduct: Pocatello

KEY MESSAGES

- Slight Risk Today (6080 mph Severe Gusts): The Storm Prediction Center (SPC) maintains a Slight Risk across the southeast corner of the regionincluding the South Hills, lower Snake Plain, and southeast highlands toward Bear Lake. Steep lapse rates and high moisture will support severe downburst winds of 60 to 80 mph and localized small hail through late evening.

- Repeat Threat Tomorrow: Near-identical synoptic conditions on Monday will keep scattered thunderstorm potential elevated across the same southeastern footprint, with localized damaging gusts remaining the primary hazard.

- Mid-Week Ridge & Late-Week Wind Surge: High pressure rebuilds Tuesday and Wednesday, bringing above-normal temperatures in the upper 80s to lower 90s alongside isolated afternoon storms. A passing northern shortwave on Thursday and Friday will increase regional winds and moderate weekend temperatures back toward seasonal averages in the low-to-mid 80s.

DISCUSSION

Issued at 156 PM MDT Sun Aug 23 2026

An active afternoon and evening are expected across eastern Idaho as an unusually moist and unstable air mass remains entrenched across the southeastern portion of the forecast area. Surface temperatures climbing into the 80s paired with surface dewpoints in the mid-50s are providing sufficient thermodynamic instability for robust convective development. The Storm Prediction Center (SPC) maintains a Slight Risk for severe thunderstorms across the southeast corner, encompassing the South Hills, the lower Snake Plain, and the southeastern highlands around Bear Lake. Soundings reveal steep low-to-mid level lapse rates, creating an environment characterized by strong evaporative cooling within convective cores. Stronger thunderstorm cores and organized outflows will be capable of generating scattered severe wind gusts of 60 to 80 mph within the Slight Risk zone, with a lower but non-negligible wind threat extending across the rest of eastern Idaho. Small hail will also be possible within the strongest cores. High- resolution convective-allowing models (CAMs) show storm activity persisting through late evening before tapering off around midnight.

Synoptically, Monday presents a near-identical setup. High- resolution model guidance targets the same general footprint across the South Hills, Snake Plain, and southeastern highlands for afternoon shower and thunderstorm coverage. SPC currently carries a Marginal Risk for severe gusts across the area. However, if daytime destabilization matches today's parameters, localized severe downburst wind gusts will once again be the primary operational threat.

As the upper-level trough assisting current convective activity exits into Western Canada, high-pressure ridging will attempt to rebuild over the Great Basin Tuesday through mid-week. Residual low-level moisture trapped beneath the ridge axis will maintain low-end daily shower and thunderstorm chances. Afternoon maximum temperatures will run a few degrees above seasonal climatological norms, reaching the upper 80s to lower 90s across lower-elevation valleys.

Heading into the late-week period, a shortwave trough tracking into Washington and British Columbia on Thursday will tighten regional pressure gradients, increasing wind speeds across eastern Idaho on Thursday and Friday. This northern feature will partially suppress the Great Basin ridge Friday into the weekend, potentially lowering valley temperatures back toward seasonal benchmarks in the low-to-mid 80s. However, considerable spread remains among model ensemble guidance regarding the exact magnitude of this weekend cooling trend.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 1041 PM MDT Sun Aug 23 2026

Expect virga showers to remain south of TAF sites overnight. Most likely looking at convection once again Monday afternoon with 30% chance of storms at TAF locations. Gusty winds and brief heavy downpours reducing visibilities are main impacts.

FIRE WEATHER

Issued at 156 PM MDT Sun Aug 23 2026

Another day with monsoon moisture across Idaho means another day with showers and thunderstorms. We will see isolated thunderstorms across the central mountains (Zone 476) and along the Montana border for Zone 411. There is a 10-40% chance for gusts over 35 mph. There is a better chance south of the Snake River across Zones 427 and 413, although coverage remains borderline for scattered and Red Flag Warning thresholds. Down south is also where we expect for a slightly higher chance for wetting rainfall, but it is still only 15-30%. There is also a 50-90% chance for gusts over 35 mph. Any thunderstorms today have the potential for gusts over 60 mph, similar to yesterday, but the chance for those types of gusts is highest down south. While there is no strong indication outflow boundaries or storms are expected across Zones 410 and 425, we will be watching for that as well. Outside of storms and outflow potential, gusty winds will develop across the central mountains(422/475/476), the Arco Desert and Upper Snake Plain (410) and along the Montana border (411). Gusts in the 25-40 mph range are expected. There will be pockets of lower humidity (around or below 15%), but the potential looks too sporadic for widespread critical conditions and Red Flag Warnings. Monsoon moisture spreads back north across eastern Idaho tonight and tomorrow. We will be borderline again across Zones 413 and 427 tomorrow for scattered coverage. We expect isolated storms across a good chunk of eastern Idaho, outside of Zone 475. The chance of wetting rain is similar to today (15-30%) but the footprint is a bit bigger overall, but still look for a mix of wet and dry storms. There is a less than 50% chance for gusts over 35 mph closer to the Montana border, but 70- 90% across the rest of eastern Idaho where storms develop, with a distinct possibility again for gusts over 60 mph with stronger storms and outflow boundaries. The risk of showers and storms continues until the end of the week. We may see another low pass to our north, which would suppress deeper moisture to south of the Snake Plain over the weekend. Right now, there is quite a range on what might have with the storm track, and the Blend of Models does include a few showers and storms across a good portion of eastern Idaho especially on Saturday.

PIH WATCHES/WARNINGS/ADVISORIES

None.