textproduct: Pocatello

KEY MESSAGES

- Isolated to scattered thunderstorms this afternoon. Gusty outflow winds possible near storms.

- Threat for showers and thunderstorms increases Thursday through Saturday.

- Locally heavy rain possible with burn scars most vulnerable.

DISCUSSION

Issued at 154 AM MDT Wed Aug 12 2026

Expect a mix of wet and dry storms today with strong gusty outflow winds possible near storms today. Most of the activity should diminish tonight.

On Thursday, a low pressure system will eject out of California and advance towards south Idaho. Models are showing a band of showers with isolated to scattered thunderstorms within and around this band of showers. This is expected to arrive Thursday afternoon with models showing quite a bit of moisture across the eastern highlands as this feature moves north. Potentially this could bring 0.25 to 0.50 inches of rain just Thursday afternoon. Confidence is moderate to high of appreciable rain on the Big Rock fire east of Idaho Falls. So have decided to issue a flood watch for the burn. While other burn scars may need watches as well with this feature moving north, this particular burn scar is the most likely to see heavy rain assuming the track of the low doesn't shift appreciably.

As we move into Friday, a secondary weaker trough will arrive from the southwest and provide the trigger for additional convection. The models seem to be favoring the central mountains into the upper Snake River highlands for appreciable rainfall with over 0.10 inches forecast Friday afternoon. So we may need additional flood watches for burn scars and possibly for the Big Rock again. On Saturday, one additional shortwave trough will move through the region resulting in scattered showers and thunderstorms with the main focus once again across the central mountains into the Island Park region. With the monsoon air firmly in place, the threat for flash flooding on these burn scars will likely continue. As we head into Sunday and Monday, a ridge retrogrades from the east and and builds across the area. This will shut down the "organized" thunderstorms. But the monsoon moisture will remain in place. So we'll probably keep continued chances for isolated storms into early next week. The forecast at this point could very well be too dry on pops with the models assuming too strong of a cap in place.

From a temperature perspective, today is the last warm day with cloud cover and showers providing cooler temperatures into the weekend. As we head into next week, temperatures rebound into the 80s but not the extreme heat that we've been experiencing.

AVIATION /00Z TAFS THROUGH 00Z FRIDAY/

Issued at 525 PM MDT Wed Aug 12 2026

TSRA not expected to last more than 1 hour into the new set of TAFs except for KDIJ, where the potential lasts until 13/04Z. Skies will improve during the evening and late night hours, but another round develops in the mid- to late morning hours on Thu for all but KSUN, first with SHRA or VCSH, but TSRA should develop in the early afternoon, around 13/19Z. Gusts should be down with decreased instability not bringing down the high momentum air, but heavier rains could impact VSBY. The abundant moisture could also bring marginal VFR CIGs along with TSRA occurrence at KIDA, KPIH, and KDIJ. KSUN, being the farthest north and the last to really feel the effects of the subtropical moisture remnants, will only see SHRA develop in the early afternoon

FIRE WEATHER

Issued at 200 PM MDT Wed Aug 12 2026

A trough situated along the PacNW coast will support decreasing temperatures under increasing cloud cover, as well as the return of monsoon moisture and daily showers and thunderstorms. Daytime highs are warming to just below normal today before turning cooler than normal for the remainder of the week. Isolated storms this afternoon will primarily impact the southeast highlands and MT Divide region. The main monsoon surge will arrive tomorrow and continue through Saturday. This will raise humidities and provide much-needed rain but also introduce frequent lightning. While thunderstorms will trend wetter heading into Friday and Saturday, a mix of wet and dry thunderstorms is anticipated Thursday. Thus, RED FLAG WARNINGS have been issued for ID Fire Weather Zones 410, 411, 413, 422, 425, 427, 475, and 476 on Thursday due to scattered thunderstorm coverage and the potential for new fire starts due to lightning. Storms over the next few days will be capable of producing gusty erratic winds up to 45 mph and locally moderate to heavy rain, which could lead to localized flooding over burn scars. Of particular concern is the Big Rock fire, which is forecast to receive approximately half an inch of rain over 48 hours Thursday and Friday, although rain accumulation will be highly dependent on whether or not storms pass directly over the fire and burn scar or not.

HYDROLOGY

Issued at 1028 AM MDT Wed Aug 12 2026

Monsoon moisture moves into our area from the south and will increase rainfall amounts and rates, especially Thursday and Friday. Any thunderstorms that develop are expected to be efficient rain producers with rain rates approaching 1 inch per hour. Most flooding concerns will be with recent burn scars. A flash flood watch is currently in effect for the Big Rock burn scar east of Idaho Falls for Thursday afternoon into the early evening. Flash flood watches will likely be needed on Friday for the Ohio fire burn scar south of Ketchum and the Wapiti fire burn scar north and west of Stanley. Outside of burn scars, localized flooding is less likely but possible, especially for any slow moving or repetitive thunderstorms.

PIH WATCHES/WARNINGS/ADVISORIES

Red Flag Warning from noon to 9 PM MDT Thursday for IDZ410-411- 413-422-425-427-475-476.