textproduct: Pocatello

KEY MESSAGES

- Weak threat of thunderstorms this afternoon and evening

- Tranquil Independence Day weather, getting hot for some with very dry humidity. Light wind.

- Thunderstorm risk returns for some on Sunday, more on Monday.

DISCUSSION

Issued at 134 AM MDT Fri Jul 3 2026

Today through Sun night...Very shallow upper level troughing will combine with a great amount of instability once the lower atmosphere heats up under strong sunshine that there is a risk of showers and thunderstorms in Custer, Lemhi, and Clark Counties in the north, and the areas south of the Snake River, especially in the southeast corner of the state. Precipitation amounts are small and the threat is very low in terms of percent coverage and occurrence. The skies completely clear late tonight and will stay mostly clear to clear for the Independence Day holiday and Sat night. By Sun afternoon, instability and a trough will trigger a return risk of showers and thunderstorms; again, not very high for either, but no longer zero, like it had been looking for Sun in previous days.

The abundant sunshine and ridge building pushes temperatures up to the point where portions of the eastern Magic Valley and Snake River plain will cross the 90 degree F threshold on the holiday, then up another 2 deg F for Sun afternoon.

As the upper level ridge strengthens, wind will remain light until perhaps Sun afternoon when a more moderate wind develops.

Mon through Thu...The clusters all have a similar pattern with the only difference being how strong the upper level ridge is. For Mon and Tue, the weak gradient aloft and south to southwest airflow that is set up could lead to an intrusion of the remnants of the southwest monsoon, and thus trigger some sort of thunderstorm activity, depending on how much moisture comes this far north. By Wed, the upper level flow shifts more westerly and this should lead to a drying out, although not all clusters are shifting that much more westerly. This could lead to a strong heat up as none of the clusters indicate any sort of shortwave breaking off a nearly stationary low off the British Columbia coast. The good news is no dry cold front appears to drive through; the bad news is that unless the moisture comes up from the southwest monsoon, it will be a very dry period, adding to the fire danger.

AVIATION /18Z TAFS THROUGH 18Z SATURDAY/

Issued at 1123 AM MDT Fri Jul 3 2026

Will see widespread VFR conditions with mainly clear skies through Saturday. Will see some thunderstorms development but less than Wednesday and Thursday this afternoon. Did put a prob30 group in DIJ after 21Z but low confidence in occurrence at the site. Tomorrow looks to be dry with mainly clear skies and no thunderstorm threat.

FIRE WEATHER

Issued at 134 AM MDT Fri Jul 3 2026

There is a risk of thunderstorms and weak showers this afternoon and evening, with only the northern Sawtooth NF and the BLM lands appearing to avoid the risk. The Independence Day holiday itself has no risk of thunder or showers, with temperatures up around 4 deg and many lower elevations crossing the 90 degree threshold for highs and afternoon humidity in those same elevations crashing below 15 percent, save for portions of the Salmon-Challis NF and the Targhee NF. This dryness continues into Sunday.

Combine this dryness with extremely deep mixing heights (instability) in the afternoon, and conditions are ripe for high intensity fires. The saving grace is the light wind expected throughout the weekend.

PIH WATCHES/WARNINGS/ADVISORIES

None.