textproduct: Pocatello

KEY MESSAGES

- Showers and thunderstorms dwindle through Monday before monsoon moisture returns Tuesday

- Gusty winds, locally heavy rainfall, and small hail possible with some stronger thunderstorms

DISCUSSION

Issued at 1258 AM MDT Sat Jul 18 2026

A few showers and a thunderstorm are possible early this morning, before we see increasing coverage this afternoon and evening across central and eastern Idaho. The best chance will remain over higher elevations, although a few storms are possible (especially with any outflow boundaries) across portions of the Magic Valley and Snake Plain. There is a risk of stronger outflow winds again this afternoon. There is a 20-50% chance for gusts over 35 mph with any outflow across the Snake Plain and Magic Valley. There is a 50-90% chance across higher terrain, especially for the central mountains and closer to the Utah border west of I-15. Stronger storms will again be capable of dropping small hail and locally heavy rainfall. There is a MARGINAL RISK for severe storms today for the central mountains, Arco Desert, and eastern highlands. Drier air works in over the weekend, BUT not enough to keep us storm free necessarily. We do end up with dry air at the surface Sunday and Monday. However, there is enough mid level moisture for a few showers and storms Sunday from around Hailey to Gilmore Summit to Island Park...as well as along the Utah border. With the drop off in deeper moisture, the potential measurable rainfall really drops. For Monday, as the ridge shifts back to the north and west, deeper monsoon moisture initially is pushed far enough west that we MAY not see any storms. It does look like virga could be an issue over the central mountains Monday. Temperatures will remain in the upper 80s and 90s for valley locations through Monday. It is not out of the question we see some spots approaching 100 across the Magic Valley and South Hills/Albion Mountains. The current HeatRisk does indicate we could reach advisory levels on Monday. At the moment, we will not be jumping on any type of headline for that.

Monsoon moisture returns starting Tuesday and will be back in place through most of next week. We will see temperatures slipping back into the 80s to low 90s by midweek due to increasing clouds, although as before daily highs will be very dependent on cloud cover.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 1125 AM MDT Sat Jul 18 2026

Isolated to scattered thunderstorms will develop once again this afternoon and linger into the evening as diurnal heating acts on lingering monsoon moisture plume over the area. Carrying PROB30 groups at all terminals from early/mid afternoon through early evening to reflect this threat. Similar to yesterday, a direct thunderstorm hit on a terminal could bring brief MVFR or lower vsbys in locally heavy rain, small hail, and wind gusts of 30-45 kts. Showers and thunderstorms will dissipate after sunset, with continued VFR conditions overnight into Sunday with just some lingering mid/high clouds. Winds will remain light (less than 10 kts) aside from any thunderstorm or outflow impacts.

FIRE WEATHER

Issued at 1258 AM MDT Sat Jul 18 2026

A few showers and even a thunderstorm remain possible this morning, before a resurgence takes place this afternoon and evening. The best chance for showers and storms will be across higher elevations, especially the central mountains and closer to the Utah border. We will be watching for any outflow boundaries and potential storms along those boundaries through sunset, with higher potential for that across the Magic Valley and Craters of the Moon (425). Coverage will be isolated, although we will be just bumping scattered coverage (25-30%) across the central mountains and also across Zones 413 and 427. We currently do not have any RED FLAG WARNINGs out for today, but that is something the day shift may to consider early on. There is a risk for stronger outflow winds over 35 mph over higher terrain (50-90%), trying to peak around 55 mph across for the same zones. Elsewhere, 35+mph gust potential is 20-50%. Locally heavy rainfall and small hail are still possible with lingering monsoon moisture today. Drier air works in for Sunday and Monday, which definitely leads to lower afternoon humidity...BUT not necessarily cutting off thunderstorm potential. For Sunday, enough mid level moisture should remain for isolated dry storms across Zones 422/476, from Hailey to Gilmore Summit), along the Montana border (411) and closer to the Utah border in Zones 413 and 427. It does look like on Monday, storm chances should drop below 10% although we may see some virga across the central mountains. With drier air and less clouds, expect warmer afternoon highs with temperatures approaching 100 in typical warmer spots Monday.

Deeper monsoon moisture returns starting Tuesday as the ridge shifts back to north and west, and keep the deeper monsoon plume in place through most of next week.

PIH WATCHES/WARNINGS/ADVISORIES

None.