textproduct: Pocatello

KEY MESSAGES

- Southern two-thirds of forecast area under marginal forecast for severe thunderstorms today and tonight.

- Thunderstorms continue with less coverage today compared to yesterday. Slight chance of thunderstorms each day through Sunday.

- Weak warming trend through Thursday, then a cooling trend to Sunday.

DISCUSSION

Issued at 140 AM MDT Mon Aug 24 2026

Today through Wed night...The upper level ridge centered over the desert southwest will strengthen over the next couple of days. This will put temperatures on a very weak warming trend, but it will not stop moist and unstable air rotating through the upper level southwest flow into southern Idaho. SPC has once again put the southern 2/3 of the forecast area in an area of marginal severe thunderstorm threat. Fortunately, this marginal threat is only expected to last through this evening. Weaker thunderstorms with lessening threat continues Tue through Thu, then beyond this the threat falls off even more. Wind outside of thunderstorms should return to being light.

Thu through Sun...As mentioned above, the trend is for less and less thunderstorm activity, barely rating mentioning during this period. However, on Thu this upper level ridge breaks down as the coastal upper level low pushes onshore in southern Canada. This movement causes the airflow to be more westerly and drier, and the incoming low increases the gradient aloft as it makes its closest approach on Thu, Fri, and Sat afternoons, when the stronger wind gets a chance to mix down to the surface. The approach of this low also produces a cooling trend that starts Thu afternoon to the end of the forecast period.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 520 AM MDT Mon Aug 24 2026

Another round of afternoon and evening TSRA. Expecting mostly just TS, so only KBYI looks like VSBY may be worse in the TSRA. Any CIGs outside of TSRA should be above FL100; with soundings having the inverted V look this afternoon and evening. SPC has put KBYI, KPIH, KIDA, and KDIJ in an area of marginal risk of severe TSRA. KSUN is right on the border. So have upped some of the TSRA gusts to G45KT. Start and stop times are based on latest available hourly guidance. Wind continues light outside TSRA.

FIRE WEATHER

Issued at 140 AM MDT Mon Aug 24 2026

Upper level high pressure has built back in, but moist and unstable air from the south continues to flow in. Except for the Salmon-Challis NF and northern end of the Eastern Idaho Dispatch center has a marginal risk of severe thunderstorms. Thunderstorms should be mainly dry, and are also becoming more isolated than scattered. Thus through Wed expect warming and drying, with continued poor recovery in the central Idaho mountains especially.

Wind will calm down from the Sunday wind event, and stay below critical thresholds through Wed. A low passing to the north, centered in southern Canada, will kick up the wind on Thu, Fri, and Sat afternoons. It also brings in cooler air, so what exactly happens to the humidity readings is up in the air, but there could be critical fire weather conditions for this period.

PIH WATCHES/WARNINGS/ADVISORIES

None.