textproduct: Pocatello

KEY MESSAGES

- Diurnal Afternoon Storms Through Thursday: Isolated afternoon and evening showers and thunderstorms will continue daily through Thursday as moisture from Nevada feeds into the western periphery of the Four Corners ridge.

- Breezy & Noticeably Cooler Weekend: An upper-level trough moving into the Pacific Northwest late Thursday into Friday will suppress the ridge, tightening regional pressure gradients and dropping weekend highs into the upper 70s to around 80F.

- Scattered Weekend Precip Chances: Embedded shortwave energy will bring precipitation chances through the weekend, with Saturday standing out as the wettest day.

DISCUSSION

Issued at 120 PM MDT Tue Aug 25 2026

Afternoon satellite imagery shows mostly clear skies across eastern Idaho, though mid and high-level cloudiness is actively streaming out of northern Nevada. This cloud deck will overspread the region over the next few hours, combining with high-elevation cumulus development to spark another round of isolated afternoon and evening showers and thunderstorms. The broad Four Corners high-pressure ridge will remain the dominant synoptic feature through midweek. Consequently, Wednesday and Thursday will showcase a near-identical weather pattern driven by a classic diurnal cycle of afternoon instability and terrain- forced convection with temperatures around 90 in the lower elevations.

A pattern shift begins late Thursday night into Friday as an upper-level trough moves toward the lower British Columbia coastline. This feature will push the Four Corners ridge southward, lowering 500 mb heights across the Intermountain West. Afternoon temperatures will begin their downward trend on Friday, falling from midweek maximums to near-seasonal averages in the mid-80s. As the core low-pressure system settles to our north over the weekend, valley temperatures will drop further into the upper 70s to around 80F. In addition to the cooler temperatures, the tightening surface pressure gradient between the building trough and southern ridge will bring increasingly breezy conditions Friday through Sunday. Shower and thunderstorm chances will linger throughout the weekend, with model guidance continuing to highlight Saturday as the wettest day of the event.

Global model ensembles show several shortwave impulses embedded within the broader cyclonic flow swinging down from Western Canada through the early part of next week. This will maintain persistent troughing across the Pacific Northwest into the start of the new workweek. As a result, temperatures across eastern Idaho will remain at or slightly below normal as we wrap up August and transition into early September.

AVIATION /00Z TAFS THROUGH 00Z THURSDAY/

Issued at 336 PM MDT Tue Aug 25 2026

Isolated to scattered storms will pose an outside threat to TAF sites this evening. Main threat would be strong gusty winds. Most convection should diminish this evening. Repeat performance for Wednesday afternoon.

FIRE WEATHER

Issued at 120 PM MDT Tue Aug 25 2026

A weak ridge of high pressure remains overhead for the next several days and will keep our overall pattern fairly steady. Each afternoon will bring isolated to nearly scattered thunderstorm activity to most of our Fire Weather Zones, but especially parts of the South Hills and Central Mountains, or zones 413, 427, 475, and 476. That said, pretty much any area could see a few isolated storms any afternoon. Through the week, most of these storms will produce little precipitation, so expect mainly dry storms with gusty outflow winds around 50 mph and lightning. That said, you could get some actual rainfall if you manage to be directly under a thunderstorm any afternoon.

Beginning late Friday and continuing through the weekend, a weak cold front will make its way through Idaho. This will bring some better organized showers and storms (and slightly improved precipitation chances) to the area. It will also bring breezy winds Friday, Saturday, and Sunday with gusts around 30 to 35 mph throughout the Snake River Plain and a cool down for the weekend where we will see highs fall into the upper 70s to near 80 degrees for both days.

PIH WATCHES/WARNINGS/ADVISORIES

None.