textproduct: Pocatello

KEY MESSAGES

- Marginal risk of severe thunderstorms in the southeast highlands today. Isolated thunderstorms forecast this afternoon and evening, and again Friday.

- Appreciable rainfall expected Friday and Saturday across much of the area.

- Today is the last hot day for a while. Strong cooling from today to Friday. Humidity trends higher.

DISCUSSION

Issued at 147 PM MDT Thu Aug 27 2026

Showers and thunderstorms have been ongoing for most of the day and continue early this afternoon. Much of southern and southeastern Idaho is included in the "Marginal" risk today from the SPC outlook. The main threat will be wind gusts around 60 mph. It appears most of this activity will be wrapped up around 9-10 PM tonight with the next round of showers arriving early Friday morning. This Pacific moisture is being funneled into our area from a combination of an area of high pressure over New Mexico and western Texas and an area of low pressure over northern Washington. Previous model runs wanted to bring the low a bit farther south into nearly central Idaho, though now it is staying just a bit farther north. Not a significant change, but one to keep watching. A track farther south could continue the trend of cooler temperatures and slightly increased precipitation. Even with this slightly "northern" track, we can still expect cooler temperatures overall and some measurable rainfall for much of the area. PWATs beginning Friday afternoon will be pushing 0.80-1.10" and a wetting rain is expected with these storms on Friday and especially on Saturday. Isolated thunderstorms return for Friday afternoon with a little break before another round of widespread showers overnight Friday into Saturday morning. Uncertainty lies within how strong afternoon convection will be either day based on how well the atmosphere is worked over in the morning and how long it will have to "recover."

As the area of low pressure moves eastward during the weekend, it will take the precipitation with it. By Sunday afternoon, any leftover activity will be more confined to the Eastern Highlands. Looking at 48-hour precipitation amounts ending Sunday morning, the NBM shows about a 30-40 percent chance of at least a quarter inch of rainfall for areas like Burley, Carey, Arco, to Fort Hall. This may be a bit overdone, but at least a tenth of an inch seems likely for much of the area. Precipitation amounts increase farther east you go with a 60 to 80 percent chance of at least a quarter inch of rainfall for the bulk of the Central Mountains and the Eastern Highlands. There's about a 30-50 percent chance of at least a half inch of rain from Stanley to Hailey and about a 60 to 70 percent chance of the same from Preston to Victor to Island Park.

High confidence remains in falling temperatures with today being the last day we see highs in the upper 80s to low 90s for a bit. By Friday afternoon, highs will be nearly 10 degrees cooler before we drop into the 70s for most on Saturday and low to mid 70s on Sunday. We'll be back into the upper 70s and low 80s by Monday and Tuesday, but it won't be quite as quick of a warm up as we've seen lately. Look for wind gusts to pick up on Saturday and Sunday, too, even outside of thunderstorm activity. Gusts will range from 25 to 35 mph each afternoon.

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/

Issued at 501 PM MDT Thu Aug 27 2026

Have prob30 thunderstorm groups at all sites other than SUN through 02 to 03Z this evening. That will be the main impact with showers or vicinity showers continuing overnight into Friday morning. Expect thunderstorms Friday afternoon as well and have included prob30s once again at all sites after 20Z.

FIRE WEATHER

Issued at 147 PM MDT Thu Aug 27 2026

Isolated thunderstorms continue once again this afternoon with a mix of wet and dry storms. We had one storm pass directly over the office this morning which brought 0.15-0.20" of rainfall with it. This is just a taste of what is to come! Storms today will be capable of producing gusty winds of 50-60 mph with a "Marginal" risk for severe weather from the SPC outlook over much of southern and southeastern Idaho. We're looking at Pacific moisture being funneled into Eastern Idaho over the next few days as we are sandwiched between high pressure over New Mexico and western Texas and an area of low pressure over northern Washington. So, while storms will be increasing in coverage for Friday and Saturday into the nearly scattered to scattered categories, we are expecting wetting rains across much of the area. You can find some specific precipitation probabilities in the discussion above, but it appears that much of the area will see at least a tenth of an inch of rainfall from Friday morning to Sunday morning with higher 48-hour totals approaching a half an inch in the higher elevations of the Central Mountains and Eastern Highlands. The main uncertainty lies with how well morning showers work over the atmosphere on Friday and Saturday and potentially limit thunderstorm coverage in the afternoons. We have high confidence in quite the cool down with this system, too. Highs will fall almost 10 degrees by Friday afternoon and highs will be in the mid to upper 70s Saturday and low to mid 70s on Sunday.

PIH WATCHES/WARNINGS/ADVISORIES

None.