textproduct: Pocatello

KEY MESSAGES

- Heavy rainfall is possible across most of central and eastern Idaho is expected through tonight, and to a lesser extent Saturday

- Strong to severe storms possible with hail and gusty winds into this evening

- Mostly dry conditions expected through next week, with a few showers and storms possible

DISCUSSION

Issued at 1116 AM MDT Fri Sep 18 2026

The strong upper low to our west continues to slowly shift east and will moves across the state tonight and tomorrow. The airmass contains a lot of moisture, even a bit more than yesterday. That means heavy rainfall is possible with stronger showers and storms, or in some cases multiple storms over the same area. There is still a risk of strong to severe storms, although things may a bit "less volatile" than Thursday, BUT the risk of hail and gusty winds is still there...and SPC continues with a MARGINAL RISK for severe storms through tonight. For Saturday, showers and storms will continue...but we will also see some pockets of dry air across the area which is typical with this type of low. Amounts across the Magic Valley, South Hills, and Albion Mountains are the "lowest", with up to 0.25" in some places. Even where amounts are lower, there will some pocket of moderate to heavy rainfall...which could lead to localized flooding issues. Elsewhere, amounts in excess of 0.50" are expected over a larger area. Of course, higher amounts are possible. We issued a more widespread FLASH FLOOD WATCH through this evening, based on 24 hour rainfall amounts and where we saw flooding taking place. The only places not included are the Magic Valley, Albion Mountains, and South Hills.

Some wraparound showers and storms are expected Sunday, mainly around Island Park and Driggs. Otherwise, it will be mostly dry through next week. The exception will be potentially Tuesday and/or Wednesday. The next low swings across the Great Basin during that period. The models are still wavering on how far north with the track, which could bring a few showers and storms especially around Bear Lake. This is actually shown in the Blend of Models forecast.

AVIATION /12Z TAFS THROUGH 12Z SATURDAY/

Issued at 150 AM MDT Fri Sep 18 2026

Another day of occasional showers and storms is expected today. Although storms will be possible just about anytime, the most likely time that storms with gusty outflows would impact TAF sites is this afternoon and evening.

FIRE WEATHER

Issued at 201 PM MDT Fri Sep 18 2026

Satellite imagery shows upper low centered near ID/OR/NV border today. Deep moisture in place today for continued threat of showers and thunderstorms through the afternoon and into early evening. Very heavy rainfall is possible, and a Flash Flood Watch is in effect for a large portion of the East Idaho fire district into the evening. Steep terrain and recent burn scars will be most susceptible to flash flooding. Gusty winds and hail will be possible in addition to the heavy rain. The center of the low will shift across East Idaho overnight with a brief break in the precipitation. The showers redevelop late overnight into early morning across East Idaho, then another round of isolated thunderstorms may be possible Saturday afternoon. The low finally shifts east Saturday night with precipitation finally coming to an end for this round. Another system looks to track through the Intermountain West/Great Basin Tuesday into Wednesday, which may bring another round of showers and thunderstorms, otherwise dry conditions are forecast.

PIH WATCHES/WARNINGS/ADVISORIES

Flood Watch until midnight MDT tonight for IDZ052>054-058>068- 070>073-075.