textproduct: Pocatello

KEY MESSAGES

- Next round of moisture arrives tonight through Friday night. New Winter Storm Warnings and Winter Weather Advisories have been issued for some higher-elevation areas.

- Frontal passage Friday brings cooler temperatures.

- Cooling temperatures and lowering snow levels will start to bring light snow accumulations to a few more of our population centers and mountain valleys late Friday and Saturday.

SHORT TERM /THROUGH FRIDAY NIGHT/

Issued at 149 PM MST Thu Dec 25 2025

Satellite imagery continues to show deep upper low off PacNW coast with southwest flow aloft continuing to bring moisture toward East Idaho. Warm air mass remains in place (with records approached or already broken for the day) under the influence of the southwest flow, and a few showers/thunderstorms exist on radar with spotter reports of light graupel early this afternoon. Next wave of moisture begins to creep into East Idaho as early as this evening. At onset this remains a high elevation snow event, with snow levels 6000-7000 ft. Gusty south/southwest winds tonight precede frontal boundary early Friday, after which snow levels gradually lower toward valley floors through the day. Upslope forcing aloft continues to focus precipitation into the central mountains and portions of the eastern highlands, and another heavy mountain snow fall event is expected. A combination of Winter Storm Warning and Winter Weather Advisories have been issued to cover the heaviest snowfall potential at or below pass level. Total QPF amounts are less than previous systems, but still enough to produce 3-6" of accumulation at lower elevations of the Wood River Region, rising to 12-18" across Galena Summit and 6-10" in the Stanley Basin. Further east, 4-8" is expected throughout the Island Park region though 6-10" are possible across the passes. Similar values are anticipated across the Big Hole region and the Bear River Range. Winds will remain gusty throughout, but anticipated to be below Advisory criteria, though will add gusty wind wording to the associated winter headlines. Late in the day Friday, temperatures fall low enough for rain to mix with or change to snow at many lower elevation areas, but the question will be whether the precipitation ends by that time, and that may not be until early Saturday morning.

LONG TERM /SATURDAY THROUGH THURSDAY/

Issued at 149 PM MST Thu Dec 25 2025

An upper level trough will move through the area to start the weekend and this will usher in our final push of widespread precipitation chances, for awhile. Much colder air will also be moving through with this system as its origin is more polar in nature than many of our previous systems over the last few weeks. That being said, precip type will be snow regionwide although there won't be too much moisture left after the sun comes up on Saturday. Still could see an additional 2-4 inches across the eastern Highlands with perhaps 1-3 across the central mountains. The Snake Plain and Magic Valley likely won't see much during the day but a dusting to around 1/2" inch is currently forecast through this corridor. Compared to much of this month, daytime highs will feel frigid with 20s and 30s in place throughout the area and these will still be running about 5 degrees above climatological norms.

The aforementioned trough will quickly shift east of the area as we move into Sunday with an upper level ridge shifting over the region to end the week. This will keep things dry throughout eastern Idaho until Thursday based off latest model guidance. Temps will be seasonal, for the first few days, running right around normal levels Sunday and Monday. The ridge will strengthen as we move into the middle part of next week with H5 heights rising once again to above normal levels. In turn, temps will respond with rising to 10-15 degrees above normal as we round out 2025 and move into 2026.

AVIATION /06Z TAFS THROUGH 06Z SATURDAY/

Issued at 1052 PM MST Thu Dec 25 2025

Precipitation will transition from rain to snow at all terminals Friday morning or afternoon behind the front with the exception of KBYI. Have forecast predominant MVFR VIS and CIGs at KPIH and KIDA, with IFR to LIFR at KSUN and KDIJ during periods of heavier snow. Confidence is fairly low in timing of CIG and VIS degradation as models show a great deal of variation. Breezy winds will persist, especially at KPIH, KIDA, and KDIJ, where wind gusts 20 to 25 kts are forecast.

PIH WATCHES/WARNINGS/ADVISORIES

Winter Storm Warning from 2 AM Friday to 5 AM MST Saturday for IDZ060-064-066. Winter Weather Advisory from 2 AM Friday to 5 AM MST Saturday for IDZ071. Winter Storm Warning until 5 AM MST Saturday for IDZ072>074.