textproduct: Pocatello

KEY MESSAGES

- Red Flag Warning in effect until 9PM MDT for parts of the eastern Magic Valley for gusty winds and very low relative humidity.

- Mostly hot, dry, and breezy through the week with isolated rain/storm chances.

- Getting windy for Friday and the weekend as a strong low- pressure system arrives to bring rain/storm chances to Eastern Idaho and a big cool down.

DISCUSSION

Issued at 1258 PM MDT Mon Jun 22 2026

A ridge of high pressure begins to build in over the West today and while we generally remain in zonal flow for this afternoon, we are beginning to feel its impacts already. Highs today warm into the mid 80s for most of our valley locations and we'll get even warmer over the next several days. Winds get breezy this afternoon with gusts of 25 to 35 mph with the strongest gusts around Richfield, Carey, and Craters of the Moon which is where relative humidity will fall to near single digits this afternoon, so a RED FLAG WARNING is in effect for this area until 9 PM MDT. Near-critical fire weather conditions will be widespread throughout most of this week due to low RHs and breezy afternoon winds. There is a very small (less than 10 percent) chance of an isolated shower or storm popping up off the terrain this afternoon, mainly up north around the Island Park area, but some of the CAMs suggest another small chance for some isolated activity in the South Hills and Southeastern Highlands tomorrow, too. And those isolated storms could produce gusts around 45 mph.

Afternoon highs remain in the upper 80s to low 90s for our valleys for Tuesday through Friday, though we do start to cool slightly by Friday afternoon. A weak shortwave passing through mid week brings about a 20 to 40 percent chance of showers and storms in the higher elevations as early as Wednesday afternoon/evening and continuing into Thursday. However, the next "big" thing to watch is the strong low models are dropping into the PNW by Saturday afternoon which then tracks through Central Idaho on Sunday. This system has the potential to bring some measurable rainfall to much of the area and a BIG drop in temperatures. Right now, the NBM takes us from low to mid 80s on Friday to mid and upper 60s on Saturday. The NBM is currently showing a 60 to 80 percent chance of highs staying below 70 degrees on Saturday and a 90 percent chance of the same on Sunday. We'll have to see if such a significant drop holds in subsequent model runs. As you might guess, this would also come with some strong winds, at least 30-45 mph.

AVIATION /18Z TAFS THROUGH 18Z TUESDAY/

Issued at 1012 AM MDT Mon Jun 22 2026

The main concerns will be some more widespread 15-25kt winds today impacting TAF sites, minus SUN, although we cannot rule out an occasional gust of 15-20kts. There will be more mid level clouds crossing southern Idaho tonight and tomorrow morning. At the moment it does not look impactful even if we end up with more virga vs. what we saw this morning with a similar area of clouds across similar areas. VFR weather should continue overall.

FIRE WEATHER

Issued at 1258 PM MDT Mon Jun 22 2026

The RED FLAG WARNING for this afternoon and evening for the Magic Valley (Zone 425) remains in place. It will be breezy over a good portion of central and eastern Idaho, so we will likely see some spots where we could see critical fire weather conditions on a smaller scale. The main concerns through at least Friday are very low humidity and warmer conditions, potential for virga/dry thunderstorms, and increasing winds beginning late in the week. The first potential issue with virga is tomorrow mainly across the Snake Plain and higher elevations south of the Plain (410, 413, and 427). At the moment, there is a LOW potential for virga and gusts over 35 mph. A few of the higher resolution models are trying to produce isolated thunderstorms, but those models have been too aggressive lately in producing any type of thunderstorm development...meaning we aren't buying that for the moment. Tomorrow night and Wednesday, mid level moisture increases with an uptick in virga/light rainfall. The best potential will be across the central mountains and along the Montana border up north (411, 475 & 476), and across higher elevations south of the Snake Plain (413 & 427). There is a little better potential for isolated dry storms, even if discounting some of the aggressive thunder forecasts. The trend creeps up a little each day Thursday and Friday, again with any potential for light rainfall across the central mountains and along the Montana/Wyoming borders (411, 413, 422, 475 & 476). This also the area for any potential of isolated dry thunderstorms. We also cannot rule virga or sprinkles elsewhere at the moment. Humidities will remain pretty low through this period, including poor overnight recovery especially across higher elevations of the central mountains and terrain south of the Snake Plain (413, 422, and 427). Any days with the potential for more widespread critical fire weather conditions would be Thursday and Friday with increasing winds. Thunderstorm coverage will likely be too low on any given day for any headlines, but given the pattern this will be something that will be watched. A stronger area of low pressure will arrive for the weekend, bringing cooler temperatures, increasing humidity, and increasing rainfall potential and at least isolated thunderstorm coverage.

PIH WATCHES/WARNINGS/ADVISORIES

Red Flag Warning until 9 PM MDT this evening for IDZ425.