textproduct: Pocatello

KEY MESSAGES

- Marginal Severe Risk Today: Monsoonal moisture pushing across the northern Great Basin will trigger afternoon and evening showers and thunderstorms, with SPC maintaining a Marginal Risk across the southern two-thirds of the area for gusty winds and small hail.

- Warm & Moderating Mid-Week (TueThu): Rain chances taper off into isolated, weaker coverage as a high-pressure ridge subtly builds over the Intermountain West, pushing lower- elevation highs back into the lower 90s through Thursday.

- Late-Week PacNW Trough & Cooldown: A prolonged upper-level trough establishing over the Pacific Northwest late Thursday into the weekend will tighten pressure gradients, resulting in breezy conditions, H5 height falls, and below-normal weekend temperatures.

DISCUSSION

Issued at 124 PM MDT Mon Aug 24 2026

Afternoon satellite imagery reveals a gradually expanding cumulus field across the northern Great Basin as another plume of monsoonal moisture pushes into eastern Idaho. Similar to recent days, another round of afternoon and evening showers and thunderstorms is expected to develop across the forecast area. While overall thermodynamic and shear parameters are less favorable for widespread severe convection than yesterday, an isolated severe storm cannot be entirely ruled out. The primary threats with stronger cores will be localized gusty outflow winds and small hail. The Storm Prediction Center (SPC) maintains a Marginal Risk for severe thunderstorms across the southern two-thirds of the forecast area through this evening, with activity tapering off into the night.

The marginal severe threat is expected to subside by Tuesday morning as atmospheric forcing weakens. From Tuesday through Thursday, weak high-pressure ridging will rebuild across the region, leading to diminishing precipitation chances and overall weaker thunderstorm intensity. While isolated diurnal showers and storms remain possible each afternoon, coverage will be far more sparse. High pressure will also drive a warming trend, with afternoon maximum temperatures returning to the lower 90s across lower-elevation valleys through Thursday.

By late Thursday and continuing into Friday, eastern Idaho will begin feeling the influence of a prolonged upper-level trough establishing itself across the Pacific Northwest. As this feature interacts with the ridge to our south, the regional surface pressure gradient will tighten significantly, generating increasingly breezy conditions Friday through the weekend. In addition to the wind, incoming H5 height falls will suppress the Great Basin ridge, initiating a cooling trend that will drop weekend temperatures to the cooler side of seasonal averages. Latest model guidance continues to introduce low-end precipitation chances as energy moves around the trough axis. Model guidance still exhibits minor variance regarding the exact depth and track of the core low as it shifts north of the region, which will dictate final wind speeds and precipitation distribution, but at least a modest cooldown remains high- confidence for the weekend.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1041 AM MDT Mon Aug 24 2026

The daily pattern of showers and thunderstorms is still around. Expect an increase by mid afternoon and continue through mid evening across eastern Idaho. We have included PROB30 for each TAF site at some point during this timeframe. We have gusts to 45kts, but higher gusts are possible especially for PIH and BYI. Some of the higher resolution models do show some potential for overnight showers and even a thunderstorm. Right now, we do not have anything reflecting that but may need add that later today or this evening.

FIRE WEATHER

Issued at 124 PM MDT Mon Aug 24 2026

Monsoon moisture continue to bring showers and thunderstorms across central and eastern Idaho throughout much of this week. The best chance through this evening will be south of a Hailey to Driggs line. The chance of wetting rains south of that line are in the 20-40% range, although we expect a decent mix of wet and dry thunderstorms. There is a HIGH likelihood for gusts over 35 mph and again potentially reaching/exceeding 60 mph with some storms or outflow boundaries. Farther north where we storms, the chance is 20-50% for gusts over 35 mph and topping out around 45 mph. We are borderline for scattered lightning coverage across 413, 425 and 427, but will not opt for an 11th hour RED FLAG WARNING due to lower confidence. It does look like we will see some showers, and maybe even a thunderstorm, overnight but chances right now remain under 20%. We see a slight decrease in monsoon moisture and subsequently the chance of showers and storms Tuesday. Right now, isolated storms are most likely across portions of 411, 413, 425, 427, 475 and 476. We may see a storm or two, or outflow boundaries elsewhere but the chance is 10% or less at the moment. That could easily change in the next 12-24 hours. The chance of wetting rain is lower tomorrow (15% or less) and the chance for outflow gusts over 35 mph is down to 20- 50% areawide. Based on the current trend, there will be an uptick in showers and thunderstorms across the central mountains (422/475/476), Magic Valley (425), and South Hills/Albion Mountains (427) on Wednesday. On the flip side, it looks like wetting rain potential barely increases and an increase in stronger gusty winds indicates more dry than wet thunderstorms. This would be our next potential day for thunderstorm coverage to reach critical fire weather thresholds. We will see how things trend in the next 24 hours in that regard. We might see a slight break over the central mountains Thursday, and areawide Sunday and/or Monday from monsoon moisture impacting us. Otherwise, the potential for seeing thunderstorms really doesn't go away for several days.

PIH WATCHES/WARNINGS/ADVISORIES

None.