textproduct: Pocatello

KEY MESSAGES

- Increasing clouds this afternoon with isolated thunderstorms.

- Wet weather arrives by Saturday for parts of east Idaho.

- Chilly weather over the weekend into early next week.

DISCUSSION

Issued at 134 PM MDT Fri May 29 2026

Satellite imagery shows two distinct circulations within incoming upper trough - one over SE Oregon and one over central Nevada. Nevada circulation shifts northeast into Utah overnight tonight, with Oregon feature moving into western Idaho/panhandle. High-res models still produce mainly isolated convection late this afternoon into this evening across portions of East Idaho. Main precipitation begins during the overnight across the southeast. Wrap-around moisture shifts ahead of the southern low, ahead of main trough axis during the day Saturday. Heaviest precipitation is still expected to lie along/northeast of a line roughly from Challis/Stanley to Bear Lake. Southwest of that line, tight gradient from wetting rains to nothing is forecast. Higher elevations across the eastern highlands should see the highest rainfall totals, trending highest to the northeast corner, where totals through Sunday could approach or exceed one inch before the trough exits. Temperatures cool into the 60s under the influence of the low for both Saturday and Sunday. Breezy winds are expected, and we may see speeds bump up against the lower thresholds for a LAKE WIND ADVISORY on American Falls Reservoir.

Trough axis shifts north into Montana late Sunday into Sunday night, but general troughiness lingers into the early part of the week. Lingering rainfall along the Divide late Sunday dwindles through the night, leaving dry conditions across East Idaho. Temperatures should be at their coolest Sunday night, and there are still expectations for portions of the Snake Plain to flirt with FROST ADVISORY conditions with lows around or just below 36 degrees, but remaining above freezing. Could see a few showers return during the day Monday under the influence of continued broad trough across the PacNW, but most of the region should remain dry. Operational GFS/ECMWF both push a weak shortwave through the flow in the Wednesday/Thursday time frame, but these appear to be outliers compared to most of the ensemble solutions. Current forecast remains dry for most areas at this time.

AVIATION /00Z TAFS THROUGH 00Z SATURDAY/

Issued at 508 PM MDT Fri May 29 2026

Convection is decreasing in coverage and intensity, with KIDA and KDIJ still a risk of TSRA for the rest of this evening. SHRA still expected at KBYI and KPIH, while KSUN has likely seen the last until Sat afternoon. There is a brief break in SHRA in the middle of the night, but after midnight, depending on the locations, SHRA start up again. Along with it comes some breezy and gusty wind, especially KBYI, but even KPIH and KIDA have G25KT during the overnight and early morning. This second round of SHRA may have an impact with marginal VFR for CIG and VSBY at KPIH, KIDA, while KDIJ may have the added problem of BR that reduce VSBY and CIG to marginal VFR, and at times down to IFR conditions for both. TSRA will redevelop in the afternoon mainly at the clearest and most likely unstable KSUN, but even KDIJ appears to have a risk of TSRA as well. If the other airdromes have a risk, it will be after 31/00Z.

FIRE WEATHER

Issued at 200 AM MDT Fri May 29 2026

An approaching low pressure system will bring increasing clouds this afternoon. This will produce cooler temps and slightly higher humidity this afternoon. A few isolated dry thunderstorms are possible this afternoon and evening. Gusty erratic winds are possible near storms. Much cooler weather with higher humidity is likely for Saturday. Wetting rains are likely for much of Salmon-Challis and East Idaho on Saturday, but not so much for South Idaho.

PIH WATCHES/WARNINGS/ADVISORIES

None.