textproduct: Pocatello

KEY MESSAGES

- Red Flag Warning Today: Critical fire weather conditions will develop this afternoon and evening across the Snake Plain. A Red Flag Warning is in effect for Fire Weather Zone 425 from 1 PM to 9 PM MDT due to wind gusts of 25 to 35 mph and minimum relative humidity plunging into the single digits and low teens.

- Warm and Dry Workweek: An amplifying upper-level ridge will bring a steady warming trend through Friday, pushing valley temperatures into the upper 80s and lower 90s. Near-critical fire weather conditions will be a daily fixture due to low humidity and breezy afternoon conditions.

- Late-Week Wind Surge: Ahead of an unusually strong early- summer storm system, the pressure gradient will tighten significantly on Thursday and Friday, causing winds to increase and elevating fire weather concerns.

- Dramatic Weekend Cooldown: A potent low-pressure system arrives Saturday, dropping temperatures 10 to 20 degrees below seasonal norms. While this will dramatically recover relative humidity values, strong and choppy winds will persist through the weekend.

DISCUSSION

Issued at 252 AM MDT Mon Jun 22 2026

Convective activity continues along and just east of the I-15 corridor early this morning. High-resolution convective-allowing models (CAMs) show these isolated showers and storms lingering for a few more hours before tapering off entirely by sunrise. In the wake of this departing activity, dry weather will take hold for the remainder of the day, with CAM guidance showing no real signature for re-development this afternoon or evening.

As skies clear, attention turns directly to fire weather concerns driven by breezy afternoon winds and low relative humidity values. This environment will be most critical across Fire Weather Zone 425, where a Red Flag Warning has been issued for Monday afternoon. Elevated fire danger will be a recurring theme through the upcoming workweek as a stable, zonal upper- level flow establishes itself over the Pacific Northwest.

Gradual rises in H5 heights are expected through mid-week as a high-pressure ridge subtly amplifies over the region. This configuration will drive a steady warming trend through Friday, keeping temperatures on the warmer side of normal. Expect daytime highs to scale into the upper 80s to lower 90s across valley floors, while higher elevations max out in the upper 70s to mid-80s.

A passing shortwave embedded within the zonal flow will bring breezier conditions on Thursday. Winds will accelerate further on Friday as the pressure gradient sharpens ahead of an unusually deep, early-summer low-pressure system progged to move inland for the weekend. Thursday and Friday will both require close monitoring for widespread critical fire weather potential. By Saturday and into early next week, the arrival of the core low will trigger a dramatic downward plunge in temperaturesrunning 10 to 20 degrees below normal. While this pattern shift will deliver excellent overnight humidity recoveries, it will keep ambient winds elevated and choppy through the weekend.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 545 AM MDT Mon Jun 22 2026

Expect VFR conditions through the period. FEW to SCT mid/high clouds early become mostly SKC conditions by midday and this will continue into Tuesday. Winds around 10-15 kts expected during the afternoon and evening hours but will become lighter during the late evening and into the overnight and first part of the day on Tuesday.

FIRE WEATHER

Issued at 252 AM MDT Mon Jun 22 2026

We begin a rapid drying trend today as yesterday's shortwave trough continues to track eastward out of the region. Minimum relative humidity values this afternoon will fall into the upper teens and low 20s across portions of eastern Idaho, paired with breezy afternoon wind gusts of 20 to 25 mph. High-resolution model guidance shows a completely dry forecast for the afternoon and evening hours, shifting the primary operational fire concern away from active convection and toward low humidity, winds, and lightning holdovers from yesterday's storms.

PIH WATCHES/WARNINGS/ADVISORIES

Red Flag Warning from 1 PM this afternoon to 9 PM MDT this evening for IDZ425.