textproduct: Pocatello

KEY MESSAGES

- Fog and low clouds will continue to affect some areas through Thursday, 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 could clear out the daily fog and stratus. However, models continue to push back on precip chances into next week.

SHORT TERM /THROUGH THURSDAY/

Issued at 127 PM MST Tue Jan 20 2026

Afternoon satellite imagery continues to show lingering low stratus throughout the Magic Valley, Snake Plain and across the Arco Desert and into the southernmost part of the Wood River Valley. Outside of these areas, the weather remains pleasant with only some mid/high level clouds in place. Where the stratus remains, temperatures continue to struggle to get out of the teens and 20s. Models continue showing this stratus layer eroding but until it does, it's hard to believe that it'll happen. That being said, continued to significantly undercut NBM high temperatures in the lower valleys for the next few days and raised overnight lows by a few degrees as well. Uncertainty remains high with the overall progression of this stratus field. When it breaks, temps will quickly climb into the 30s and lower 40s across valley locations but just no real idea as to when it'll occur. Could be tomorrow, could be Thursday or Friday. The one certainty is that with this weather pattern in place, things will remain dry with only the fog/stratus to be concerned with for awhile.

LONG TERM /THURSDAY NIGHT THROUGH MONDAY/

Issued at 127 PM MST Tue Jan 20 2026

The extended portion of the forecast remains generally uneventful into early next week with no high-imnpact weather systems expected. Could still be dealing with lingering fog/stratus in the lower elevation valleys in the latter part of the work week. Models do show some upper level impulses swinging through the area late Friday and again on Sunday which COULD help to clear some of this stratus out and perhaps spark some very isolated high elevation precip chances although models seem to be backing off on the latter. As for the former, stay tuned. In short, things look strangely quiet for the latter part of January across eastern Idaho.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 1056 AM MST Tue Jan 20 2026

No major changes to the forecast at this point with high pressure still overhead and fog and stratus still impacting all sites. Currently, the stratus layer is right around 500 ft, so most sites are experiencing IFR CIGs this morning and bouncing back and forth between VFR, MVFR, and IFR VIS, so the TAF chase continues. Stronger winds at SUN did not develop this morning, so the light winds have pulled the stratus up the valley into SUN. Not expecting big improvements there until later tonight when the wind shift occurs to be back down valley. DIJ is currently the only sites with 10SM and sky CLR, though not sold that will continue all afternoon with the weak shortwave passing through that area. Models still want to break us out of the stratus/fog this evening, but confidence in that is low. IDA is most likely to remain socked in all day and into tonight. Even if BYI and PIH get a break, it will likely be short- lived before more redevelopment overnight. SUN will likely be the only site that gets a reprieve tonight.

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 Thursday for IDZ054-059.