textproduct: Pocatello

KEY MESSAGES

- Breezy & Warmer Thursday/Friday: High pressure breaks down on Thursday as a Pacific Northwest trough approaches, driving lower-elevation highs into the 80s alongside gusty winds that linger through Friday.

- Weekend Temperature Roller Coaster: Southerly flow pushes temperatures into the mid-80s on Saturday before a potent cold front triggers a 15 to 20 degree temperature drop on Sunday, holding daytime highs in the 50s and 60s.

- Weekend Rain Potential: Rain chances arrive Saturday night and linger into Sunday, with precipitation focused across northern zones including the Central Mountains, Continental Divide, and Island Park.

- Dry & Moderating Early Next Week: High pressure rebuilds Monday through mid-week, clearing precipitation and initiating a steady warming trend.

DISCUSSION

Issued at 136 PM MDT Wed Sep 9 2026

Afternoon satellite imagery shows clear skies across eastern Idaho under weak high-pressure control. Temperatures will top out in the upper 70s to near 80F late this afternoon before skies remain clear overnight. Pattern changes begin Thursday as an approaching Pacific Northwest upper-level trough tightens the regional pressure gradient. Winds will increase markedly on Thursday alongside a warming trend that will push valley highs into the 80s. Breezy-to-windy conditions will persist through Friday. Slightly lower 500mb heights on Friday will bring a subtle temperature dip, while shortwave energy rotating out of British Columbia aids in consolidating a more potent upper-level low to our northwest. Aside from a low-end shower chance on Friday, conditions will remain predominantly dry through late Saturday afternoon.

The incoming weekend low will drive a sharp temperature roller coaster across eastern Idaho. Strong southerly flow ahead of the trough axis will pump unseasonable heat back into the region on Saturday, pushing lower-elevation highs into the mid-80s. A sharp cold front will cross the area Saturday night into Sunday, bringing a dramatic 15 to 20-degree temperature drop. Highs on Sunday will struggle to escape the 50s and 60s amidst continued gusty winds. Precipitation will overspread the region Saturday night into Sunday, with atmospheric moisture focused primarily across northern zones, including the Central Mountains, Continental Divide, and Island Park.

In the wake of the exiting low, precipitation will wrap up early Monday, leaving seasonably cool and dry conditions to start the workweek. Global models show high-pressure ridging overspreading the Intermountain West Tuesday into Wednesday, initiating a steady warming trend and ensuring dry weather through mid-week.

AVIATION /18Z TAFS THROUGH 18Z THURSDAY/

Issued at 1154 AM MDT Wed Sep 9 2026

VFR conditions in place through the period with mainly clear skies and winds generally around 10 kts or less through the period. Winds will increase just beyond 10/18Z and be breezy at times on Thursday. No precip is expected.

FIRE WEATHER

Issued at 116 PM MDT Wed Sep 9 2026

Main impact will be winds through Sunday. Have issued a red flag warning for zone 410 noon through 8 pm Thursday for low relative humidity and gusty winds. Should have 30 mph gusts with widespread relative humidity below 15 percent with the warming trend continuing. Strongest winds in the Arco Desert and INL region. Think other zones will not have quite strong enough winds or widespread enough for warnings. Will be breezy to windy again on Friday with again zone 410 the main region closest to red flag conditions once again. Relative humidity will likely be a bit higher and more marginal than Thursday with cooler high temperatures. Breezy to windy conditions expected again Saturday with a strong cold front and more wind again on Sunday, but much cooler temperatures will cause significantly higher humidity. So after Friday do not think widespread red flag conditions will be met. Best chance for any showers and convective activity will be with the Sunday system. Prior to that only very slight chances.

PIH WATCHES/WARNINGS/ADVISORIES

Red Flag Warning from noon to 8 PM MDT Thursday for IDZ410.