textproduct: Pocatello

KEY MESSAGES

- Flood Watch Through Monday Afternoon: Today is the main event for precipitation, with 1 inch or more expected for most areas along and east of the I-15 corridor. Localized totals of 2 to 3 inches are possible across the higher terrain of the eastern highlands and around Island Park. A brief break in precipitation is possible later this evening before a secondary surge of moisture pushes in from Nevada and Utah overnight into Monday morning.

- Raw & Chilly Through Tuesday: A deep upper-level trough will keep dense cloud cover and unseasonably cool temperatures locked over eastern Idaho, with daytime highs limited to the 40s and 50s.

- Late Week Ridge & Pleasant Next Weekend Possible: Precipitation clears out by mid-week as the low departs. High pressure ridging will bring clearing skies and temperatures rebounding to seasonal norms by Thursday and Friday, setting up a much more pleasant next weekend.

DISCUSSION

Issued at 105 PM MDT Sun Oct 11 2026

Widespread cloud cover has resulted in a wet, raw day across eastern Idaho, with daytime temperatures struggling in the 40s and low 50s. Deep moisture continues to surge into the region from the south, fueled by the remnants of Tropical Cyclone Rachel. This tropical moisture is interacting with cooler air filtering down from the north as deep upper-level troughing becomes firmly established over the Pacific Northwest.

Today serves as the main event for precipitation. An inch or more of rainfall is expected for most areas along and east of the I-15 corridor. Localized spots could certainly see 2 to 3 inches, especially across the higher terrain of the eastern highlands and around Island Park. Accordingly, a Flood Watch remains in place through tomorrow afternoon. High-resolution convective-allowing models (CAMs) indicate a potential break in precipitation later this evening before a secondary surge of moisture advances into the area out of Nevada and Utah overnight and into Monday morning. Temperature forecast tonight is a bit tricky with cloud cover and precip in place. Nevertheless, a Freeze Warning has been issued for the Magic Valley and across the Lava Beds and into the Arco Desert as these zones likely have the best potential to see temps drop below freezing, briefly. A Frost Advisory was issued for the Snake Plain with widespread temps of 32-36 expected overnight. Not out of the question that some rural spots within these zones drop to near, or below freezing, but confidence is very low with all the clouds and precip forecast to be around. Either way, many nights ahead with Frost/Freeze headlines expected followed by a suspension of the growing season for the year later this week.

Models continue to develop a closed low that will move slowly across the Great Basin and into the Intermountain West between now and mid-week. This synoptic feature will keep dense cloud cover and precipitation chances in place through at least Tuesday. Following Monday morning's moisture surge, the precipitation focus will shift toward the far southeastern corner of the forecast area late Monday into Tuesday as the upper low tracks from Nevada into Utah. Conditions will remain seasonally chilly, with high temperatures predominantly in the 50s.

Conditions will begin to steadily improve Wednesday and Thursday as the upper low slowly moves east of the region. While the ECMWF (Euro) continues to hint at retrograding the low back into Utah, the vast majority of ensemble clusters suggest this is an outlier solution. Consequently, confidence remains moderately high that ridging will settle over the area later in the workweek. This pattern shift will allow for clearing skies and moderating temperatures, bringing highs back closer to seasonal norms by Thursday or Friday. Following this week's raw weather, next weekend is looking to be much more pleasant.

AVIATION /06Z TAFS THROUGH 06Z TUESDAY/

Issued at 1011 PM MDT Sun Oct 11 2026

Precipitation has dropped off with mostly VCSH for all sites currently. There is enough moisture remaining combined with much cooler temperatures that all sites are currently MVFR/IFR except BYI. All TAF sites could rise slightly before the next wave of moisture. However, models are not indicating a rise. Models still show the next wave of moisture for all sites early this morning and going to mid to late morning. Expect IFR/MVFR conditions CIGS and VIS for all sites with additional moisture. The HRRR model is now showing a break in moisture tomorrow afternoon, which could bring sites up to VFR conditions. However, their are still multiple models showing the potential of moisture tomorrow afternoon, which would keep MVFR/IFR conditions. The most likely window for VFR conditions is in the early evening tomorrow when precipitation is most likely to drop off.

FIRE WEATHER

Issued at 105 PM MDT Sun Oct 11 2026

Widespread light to moderate rainfall is in place across much of East Idaho, with the heaviest precipitation in the Snake Plain and southern/eastern highlands. Light showers also exist across the central mountains. Additional amounts of 0.70-1.50" are still forecast for the eastern half of the Snake Plain and areas south/east. Further west, additional accumulations range 0.15-0.60". If the higher probabilities seen in the models can be realized, additional amounts over 2.5" are still possible through Monday. Cooler temperatures will produce light accumulations at higher elevations, with light falling snow possible to mid-slope overnight tonight. Upper low finally sags south of the region Monday night into Tuesday, allowing drier air to move back into the region into midweek. High pressure continues to build late in the week through the weekend, allowing for a gradual warming trend.

PIH WATCHES/WARNINGS/ADVISORIES

Flood Watch through Monday afternoon for IDZ051>067-073-075. Freeze Warning from 3 AM to 9 AM MDT Monday for IDZ051-052-055. Frost Advisory from 3 AM to 9 AM MDT Monday for IDZ053-054.