textproduct: Pocatello

KEY MESSAGES

- Mostly dry today and Thursday.

- Cool again today before warming slightly for Thursday and Friday.

- Expect a wet, chilly Halloween/weekend, especially on Sunday.

DISCUSSION

Issued at 1204 PM MDT Wed Oct 28 2026

There is currently dry, zonal flow aloft over southern Idaho. Also, currently there is an upper level low centered just off the coast of central British Columbia with another upper level low centered off the coast of central California. These upper level lows will drive the weather/precipitation over the upcoming weekend.

Today will be dry as we transition from zonal flow aloft to southwesterly flow aloft. Highs today will be very similar to yesterday, generally in the mid 40s to low 50s. Wind gusts today will be around 25 mph across the Arco Desert/INL and around 15 to 20 mph elsewhere.

The bulk of Thursday will also be dry as temperatures warm just a few degrees with southwesterly flow aloft. Thursday morning look for patchy fog, especially in lower elevations near water sources. Expect temperatures in the low to mid 50s for most lower elevations on Thursday. Look for overall light winds Thursday too.

By very late Thursday night or very early Friday morning, our next system is just beginning to bring the start of some precipitation to southeastern Idaho. An area of low pressure off the coasts of the Washington and Oregon will be just starting to pull in some Pacific moisture into southeastern Idaho. It is this low off the Oregon and Washington coasts that moves inland during the weekend bringing cooler air and good precipitation chances. Deep troughing over the West will transport even more moisture into our area from the other upper level low over Southern California going into late Saturday and, especially, Sunday.

The current trend has been to decrease QPF on Friday, allowing temperatures to stay "warm" for one more day before more organized showers arrive for the weekend and bring a cool down. On Friday, the more limited precipitation we do have around will likely favor parts of the Central Mountains. The rest of the higher elevations will start to receive precipitation Friday afternoon/evening before showers become more widespread and steady late Saturday into Sunday. Saturday late afternoon into the early evening models still show a chance for 0.02 to 0.10 of rain across lower elevations that will likely have impacts on Halloween activities. The bulk of the precipitation is still arriving late Saturday through Sunday and lingering into Monday morning.

While total QPF numbers continue to change from model run to model run, there currently is at least a 50-70 percent chance that all of our CWA across southeastern Idaho sees at least 0.25 inch of precipitation from Saturday morning to Monday morning. Plus, for some higher elevations, especially the farther east you go, those 48-hour totals will likely be closer to 0.75-1.50 of liquid precipitation. Temperatures will also drop with highs on Sunday and Monday being the low to mid 40s for most areas. As a result, expect better snow amounts especially for our northern areas (Central mountains and the Montana Divide) above 6500 to 7500 feet with 6 to 12 inches of snow likely for Central mountains (to include the Salmon river mountains, Sawtooth mountains, West Smokys mountains, Smoky mountains, White Cloud mountains, Boulder mountains, Pioneer mountains, White Knob mountains and the Lost river range). Higher elevations for the Pioneers and Big Lost range could see up to 18 inches of snow. Galena Summit has 12 inches of snow currently forecasted. Areas across the Montana Divide will see 6 to 12 inches of snow above 7000 to 7500 feet as well. The Eastern Highlands is a little less certain with snow levels. The snow levels look to be higher when more precipitation moves through on Sunday, with snow levels around 8000 to 9000 feet. These areas, especially in the Wasatch Idaho mountains above 8000 to 9000 feet, will get 6 to 12 inches of snow too.

AVIATION /12Z TAFS THROUGH 12Z THURSDAY/

Issued at 532 AM MDT Wed Oct 28 2026

Predominant VFR expected through the period as we have dry weather in place before a system moves in for the weekend. Winds should be light and generally variable aside from the KSUN diurnal wind regime. As has been the case for the past few days, there is a non- zero chance for some low CIGs at area terminals but chances are too low to include in the forecast.

FIRE WEATHER

Issued at 239 AM MDT Wed Oct 28 2026

Dry conditions expected for today and tomorrow as we transition from zonal flow to southwesterly flow aloft. This will warm us up a few degrees, but min RHs will still be around 40-50 percent across the whole area. Wind gusts today will be in the 15-25 mph range. Precipitation returns to the forecast very early Friday morning for the Central Mountains and then spread eastward and becomes more widespread through the weekend. While total QPF numbers continue to change from model run to model run, there currently is at least a 50- 60 percent chance that all of our CWA sees at least a quarter inch of precipitation from Saturday morning to Monday morning and in some higher elevations especially the farther east you go, those 48-hour totals may be closer to 0.75-1.00 of liquid precipitation.

PIH WATCHES/WARNINGS/ADVISORIES

None.