textproduct: Pocatello

KEY MESSAGES

- High elevation snowfall event through today. Winter Storm Warnings and Winter Weather Advisories remain in effect for some areas.

- Weather pattern remains active through Christmas week.

- Continued well above normal temperatures through Christmas. Slight cooling but still above normal next weekend.

SHORT TERM /THROUGH TONIGHT/

Issued at 253 AM MST Mon Dec 22 2025

Moist W-SW flow off the Pacific continues to support rain and snow over large portions of southeast Idaho early this morning. Snow levels have been rising, and have cancelled the Winter Weather Advisory for the Wood River Foothills/southern Wood River Valley with all rain now falling there. Snow is mixing with rain in some of our other advisory/warning areas as well. Areas of precipitation will generally continue today, lifting northward tonight into Tuesday morning as winds shift more into the SW with low pressure amplifying off the California coast. Snow levels will generally run as high as 8,000 feet across the southern highlands to as low as 6,500 feet at times up over the Central Mountains. Expect high temperatures to reach the 40s and low 50s today.

LONG TERM /TUESDAY THROUGH SUNDAY/

Issued at 116 PM MST Sun Dec 21 2025

We are still looking at a band of rain and snow to lift northwest out of our are Tuesday as another low helps reload the pattern to our west. For Christmas Eve day and night, we see a quick but potentially healthy shot of rain and snow across central and eastern Idaho. With strong southerly flow into our area, we are looking at fairly strong upslope into places like the Wood River Valley, Arco, Monida Pass, and Island Park. Meanwhile, downslope is likely along and south of the Snake River into the Teton Valley. We did knock down the precipitation amounts a bit as it appears the numbers might be influenced by some unrealistic amounts coming from the GFS. The latest precipitation amounts are in the 0.30-0.70" range where the bulk of the moisture falls. Places like the Challis and Pahsimeroi Valleys are looking at a major shadow effect and closer to 0.10" or less. Higher elevations are looking at upwards of 1" in favored areas. There are a few pockets of 1.0-1.25" currently in the forecast, which is somewhat backed up by probability forecasts that have a 20-40% chance of more than 1.0". If you took the GFS at face value, we COULD have another 0.20-0.50" across the area. Do expect these numbers to change as we get closer, but just beware that this time period could be another wet and impacted travel period for us. The ECMWF is a bit slower than other models, and actually holds on to heavier precipitation especially across the central mountains for Christmas. The rest of the model numbers point to keeping some showers around but nothing too crazy amount-wise. Our Blend of Models is NOT following the ECMWF's plan at the moment. The latest trends in the extended models and Blend of Models is to dry things out by the end of the extended holiday weekend. The GFS, earlier run of the ECMWF and Blend of Models close a low off well to our southwest over the weekend and pulls all of the moisture out of Idaho. Temperatures through Christmas remain well above average, with cooler temperatures returning as early as Friday. Even then, the current forecast has highs at or just above average.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 445 AM MST Mon Dec 22 2025

Areas of rain and showers continue today, with little consensus in model guidance on declaring any organized breaks at this time. Precip type should stay rain from this point forward, which will help keep vsbys up. Have started timing out an end to the precip this evening into tonight as the moisture flow shifts north of southeast Idaho. Overall VFR conditions are expected, but drops into MVFR will be possible, with KSUN and KDIJ the best candidates. Cigs so far early this morning have been a bit higher/better compared to NBM guidance...will be interesting to see if this continues or things nudge down here over the next several hours. Our cig forecast runs somewhere in between current obs and the NBM.

PIH WATCHES/WARNINGS/ADVISORIES

Winter Weather Advisory until 11 AM MST this morning for IDZ060-064-066. Winter Storm Warning until 11 AM MST this morning for IDZ071>074.