textproduct: Pocatello

DISCUSSION

Issued at 209 AM MDT Sat Aug 8 2026

The heat is the main weather impact this weekend with a HEAT ADVISORY continuing for the eastern Magic Valley, South Hills, and Snake River Plain. It's within these areas that highs today will push towards 100 degrees again and only drop into the low to mid 60s overnight into Sunday. Some wildfire smoke lingers across the area today, but the main impacts from that are expected to be a bit more confined to Custer County where an Air Quality Alert remains in effect through Monday afternoon. In addition to the heat and smoke, a RED FLAG WARNING is also in effect for the Central Mountains this afternoon. This is due to gusty afternoon winds around 25 mph and minimum relative humidity falling to 10 to 15 percent. Outside of this area, wind gusts will range from 20 to 30 mph with the strongest gusts out across parts of the Arco Desert. There is a very small chance (10 to 15 percent) for an isolated shower or storm in parts of the South Hills and up north along the Idaho/Montana divide as a bit of moisture does its best to work up and around the high pressure over our area. Expect Sunday to be a nearly identical weather day. The ridge of high pressure gets flattened a bit early next week as an area of low pressure moves into British Columbia and troughing extends southward into the Pacific Northwest. Where that low will track throughout the rest of the week is not exactly resolved yet by the longer range models, but afternoon highs will slowly decrease during the week, falling to the low to mid 80s by next Friday. Isolated shower and storm chances will be around through next week, but it may not be until the end of the week/next weekend that we finally see some potential for more widespread precipitation.

AVIATION /00Z TAFS THROUGH 00Z SUNDAY/

Issued at 934 PM MDT Fri Aug 7 2026

Some mid- and high level cloudiness is expected to develop during the afternoon and early evening over each and every airdrome on Sat. The upper level ridge that has dominated the weather for over a week is starting to deteriorate and shift eastward. TSRA made it to the ID-UT border on Fri afternoon, and this area will push into southern ID on Sat, so there is actually a VCSH for KBYI. But it would have a hard time pushing farther north with the upper level wind strongly out of the west over the remainder of the region. This mid- and high level moisture could develop some CIGs, but at that elevation they are not impactful. Mostly likely CIG airports are KPIH and KBYI.

Wildfire FU continues to be an issue. However, growing instability in the afternoon should keep FU from impacting VSBY much in that time of day, save perhaps for KSUN when the wind shifts to the south and pushes the FU into the Wood River valley. KPIH and KIDA have a risk in the morning before the inversion breaks.

Wind is expected to be somewhat stronger in the afternoon, with G20KT or G25KT possible with sustained of 15KT at most locations. Afternoon direction should be based on slope-valley phenomenon and not an issue of cross wind.

FIRE WEATHER

Issued at 209 AM MDT Sat Aug 8 2026

A RED FLAG WARNING is in effect for the Central Mountains (Fire Weather Zones 475 and 476) later today from 1 PM to 9 PM MDT due to gusty winds and critically low min RHs. Within this area, min RHs will fall to single digits in some spots, but generally remain in the 10 to 15 percent range this afternoon. Expect wind gusts of 20 to 25 mph. Outside of the Central Mountains we will see near-critial fire weather conditions with gusts of 20 to 30 mph and min RHs of 10 to 20 percent. A very small chance (10 to 15 percent) of an isolated shower or storm will exist today in the South Hills and Island Park area as just a bit of moisture tries to work its way up and over the ridge of high pressure. There will be little change in the forecast for Sunday as that high pressure remains in control of the pattern. Things begin to change throughout next week, but it will be a slow change. Troughing begins to move into the Pacific Northwest early next week thanks to an area of low pressure moving into British Columbia. This will drop afternoon highs by just a couple of degrees each day as wind gusts stay in the 20 to 30 mph range. While there will be some isolated shower/storm chances during the afternoons in the first half of next week, we may have to wait until the end of next week before we see the chance for more widespread precipitation to increase.

AIR QUALITY

Issued at 209 AM MDT Sat Aug 8 2026

An Air Quality Advisory remains in effect for Custer County through Monday afternoon due to air quality expected to remain in the "moderate" to "unhealthy for sensitive groups" categories.

PIH WATCHES/WARNINGS/ADVISORIES

Heat Advisory until 11 PM MDT this evening for IDZ051>059-062. Air Quality Alert until 3 PM MDT Monday for IDZ068>074. Red Flag Warning from 1 PM this afternoon to 9 PM MDT this evening for IDZ475-476.