textproduct: Pocatello

KEY MESSAGES

- Fog and low clouds will continue to affect some areas through Tuesday, especially during the overnight and morning periods, amid a continued quiet weather pattern for the region.

- A pattern shift is expected by Friday with a trough moving through, which should clear out the daily fog and stratus. However, models have pushed off any precipitation until next weekend.

SHORT TERM /THROUGH TUESDAY NIGHT/

Issued at 206 PM MST Mon Jan 19 2026

A strong ridge of high pressure will continue to dominate over the region keeping conditions dry with light winds and mostly clear skies outside of our lower valleys. Throughout the Snake Plain and Magic Valley, air stagnation and valley fog will remain problematic keeping low ceilings and freezing fog a concern into the day Tuesday. Afternoon satellite isn't showing much in the way of erosion of the stratus across these lower valleys and our solar heating is quickly diminishing so the likelihood of seeing any widespread breaks appears to be diminishing and will likely linger into the day tomorrow. As such, high temperature forecasts remain a high bust potential without seeing any clearing and breaking of the inversion. Adjusted temps down this afternoon accordingly as areas that stay socked in will likely remain in the 20s but even just some brief clearing should allow temps to get into the 30s, briefly, in spots. Will likely see similar issues on Tuesday so adjusted temps downward accordingly to account for this.

LONG TERM /WEDNESDAY THROUGH MONDAY/

Issued at 206 PM MST Mon Jan 19 2026

From Wednesday into the weekend, eastern Idaho is generally expected to stay dry and relatively seasonal temperature-wise under a continued ridge of high pressure. This should lead to mostly sunny to partly cloudy skies each day although some localized inversions low stratus /fog could continue to remain problematic especially in the lower valleys. As a whole though, no significant storm systems appear to be on the horizon into the weekend although maybe some low end PoPs could be realized across the higher terrain later this week, it likely won't amount to much. Expect things to remain generally quiet.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 421 PM MST Mon Jan 19 2026

Main impact stratus deck running through Snake River Plain and IFR to LIFR status at BYI, PIH and IDA. For now kept those conditions persistent through 19Z. Low confidence in timing of erosion of stratus deck as seeing some erosion to the north right now. SUN and DIJ expected to be VFR through Tuesday. Light winds expected to continue.

AIR QUALITY

Issued at 1244 PM MST Sun Jan 18 2026

We have extended the AIR STAGNATION ADVISORY out through Tuesday for now. We really haven't seen any movement of poor air across the Pocatello area as well as across the Cache Valley, even with the flow more northerly and no longer directly under the ridge. This pattern should hold through Tuesday. We do see the pattern change, or more of a shift farther west again, by midweek. The issue that we will see increase in wind and precipitation, but moisture potential is lower than before and the pattern shift may not be strong or different enough to completely scour things out especially down near the Utah border. Stay tuned.

PIH WATCHES/WARNINGS/ADVISORIES

Air Stagnation Advisory until noon MST Tuesday for IDZ054-059.