textproduct: Pocatello

KEY MESSAGES

- Light showers are possible across mainly higher terrain overnight and then light to moderate showers and thunderstorms for the Eastern Highlands Saturday afternoon

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

- Expect warming temperatures through the week with temperatures in the mid to upper 70s/low 80s by the end of the week

UPDATE

Issued at 722 PM MDT Fri Sep 18 2026

Convection has backed off across the area. Thus, have cancelled the flood watch. We never got instability for widespread showers and thunderstorms, mainly because of too much cloud cover. Expect light showers this evening mainly for the northern Central mountains, Montana divide, and the Eastern Highlands this evening into tomorrow morning. As the upper level low (that is currently centered over southeastern Idaho) moves east overnight into tomorrow morning expect light showers mainly for upslope areas along the eastern Snake River plain benches and the Eastern Highlands east of I-15 and along the Wyoming border. With heating tomorrow expect, mainly isolated showers and thunderstorms mainly for the Eastern Highlands.

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 /06Z TAFS THROUGH 06Z SUNDAY/

Issued at 1029 PM MDT Fri Sep 18 2026

VFR conditions are very likely through the period. Models have backed off on wrap around precipitation for early this morning. Models still show afternoon isolated showers and thunderstorms for mainly the Eastern Highlands. Have put VCSH for all TAF sites starting around noon. Have only put in a PROB30 for thunderstorms for DIJ for Saturday afternoon. Expect overall light winds during the day except near any thunderstorms. Winds drop off quickly tomorrow evening becoming light and variable with mid to high clouds.

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

None.