A storm system brought heavy snow to the Caribou Mountains.
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The episode as NWS PIH wrote it up.
A storm system brought heavy snow to the Caribou Mountains.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Pocatello, ID wrote its last area forecast discussion before the first event at Dec 13, 2:20 AM MST, 4 hours 40 minutes earlier.
Area Forecast Discussion National Weather Service Pocatello ID 220 AM MST Sun Dec 13 2020 .SHORT TERM...Today through Tuesday night. A broad upper trough will work its way into the region from the west later this evening. Snow may begin in the Central Mountains as early as this afternoon, and overspread the rest of southeast Idaho tonight. Have generally seen consistent snowfall projections among the models with recent runs, so no major changes to accumulations. Generally expect to see 1 to 3 inches for the Snake Plain along the Interstate corridors with 3 to 5 inches in the higher elevations of the Southeastern and South Central Highlands. The upper trough will continue eastward and exit the region Monday afternoon, followed by a brief period of ridging. Models are showing potential for precip under the ridging, but this may be flurries coming from low stratus. A weak trough will work its way into the area Tuesday afternoon/evening, triggering some more snowfall, though accumulation look to be light, and most favoring upslope areas in the Southeastern Highlands. Hinsberger .LONG TERM...Wednesday through Sunday. Unsettled active pattern continues through the weekend. Models remain in decent agreement on general timing of systems. Weak system Wednesday targets mainly higher elevations, but stronger system arrives for Thursday through early Friday. Brief break late Friday/Friday night followed by weak system Saturday, and next big system arriving Sunday. The system for Thursday/Friday may be interesting as the ensemble precipitation spreads are targeting more significant snowfall at higher elevation locations than we have seen out of the past several weaker storms. Interestingly, the longer term outlooks for snowfall are hitting the Sunday and beyond system a little harder as well. Obviously a lot can happen over the next several days to shift amounts in one direction or another. DMH && .AVIATION...Satellite imagery shows broad area of high cloud cover streaming across East Idaho early this morning, but also small batches of low stratus/fog across portions of the upper Snake Plain and Island Park region. Expect the increasing high clouds to help limit radiational cooling for stratus/fog, but still can't rule out occasional pockets of MVFR or even LIFR in/near KIDA or KDIJ through about 15Z. Otherwise expect VFR conditions throughout most of the day all sites. Around or just after 00Z we begin to see conditions deteriorate rapidly at KSUN with onset of light snow. These conditions spread across all of the East Idaho terminals relatively quickly, generally before 06Z. Expect ceilings lowering to at least MVFR but more likely IFR with occasional pockets of LIFR for the remainder of the terminal period. DMH && .PIH WATCHES/WARNINGS/ADVISORIES... None. &&
Special Weather Statement National Weather Service Pocatello ID 230 AM MST Sun Dec 13 2020 IDZ053>066-132200- Upper Snake River Plain-Lower Snake River Plain- Eastern Magic Valley-Southern Hills/Albion Mountains- Raft River Region-Marsh and Arbon Highlands- Franklin/Eastern Oneida Region-Bear River Range-Bear Lake Valley- Blackfoot Mountains-Caribou Range-Big Hole Mountains-Teton Valley- Centennial Mountains - Island Park- Including the cities of Idaho Falls, Rexburg, St. Anthony, Pocatello, Blackfoot, American Falls, Shelley, Fort Hall, Burley, Rupert, Heyburn, Oakley, Albion, Almo, Malta, Rockland, Holbrook, Inkom, McCammon, Downey, Lava Hot Springs, Malad, Preston, Thatcher, Emigration Summit, St. Charles, Montpelier, Georgetown, Grace, Soda Springs, Henry, Bone, Wayan, Swan Valley, Victor, Ashton, Tetonia, Driggs, Island Park, and Kilgore 230 AM MST Sun Dec 13 2020 ...SNOW TO WORK ITS WAY INTO SOUTHEAST IDAHO THIS EVENING... Snow is back in the forecast tonight as an area of low pressure moves in from the west. Total snow accumulation will be around 2 inches along the I-86 and I-15 corridors, and along HWY 20 up to Rexburg. Higher elevations south and east of the interstate corridors could see around 3 to 5 inches of snow tonight and tomorrow. Use caution when driving and be prepared for slick roads and reduced visibility.
The national radar mosaic for the moment the first event began.
1 heavy snow. Local standard time, as filed.
Estimated snow amounts from SNOTEL sites were 12 inches at Giveout and 11 inches at Somsen Ranch.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Idaho in 2020Every state in 2020This day in weather historyWarnings in Idaho, December 2020
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 929728.