A large upper level trough extending over the Pacific Northwest and Intermountain region spread heavy snow across Southwest Idaho and Southeast Oregon.
Every event with a place to put it; 5 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS BOI wrote it up.
A large upper level trough extending over the Pacific Northwest and Intermountain region spread heavy snow across Southwest Idaho and Southeast Oregon.
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 Boise, ID wrote its last area forecast discussion before the first event at Dec 23, 8:29 PM MST, 5 hours 31 minutes earlier.
Area Forecast Discussion
National Weather Service Boise ID
829 PM MST Fri Dec 23 2016
.DISCUSSION...The only changes made to forecast were to lower
overnight minimum temperatures across the area, as several
locations were already lower than their forecasted values. Periods
of snowfall continue this evening due to moisture coming up from
the southwest. However, radar is demonstrating spotty coverage
associated with this moisture and most snowfall has been light.
The second true surge of moisture associated with this pattern is
anticipated to move over the area late this evening, and is
anticipated to produce periods of moderate snowfall and
accumulations especially across the valleys through the late
morning.
No changes made to existing winter weather highlights, except for
the expiration of Harney county.
&&
.AVIATION...Mountains obscured. Areas of MVFR conditions due to low
stratus and fog, with local IFR/LIFR conditions in snow showers.
Widely scattered snow showers at 03Z, becoming widespread after 09Z
along with deteriorating conditions. Surface winds generally 12
knots or less, except easterly 15-20 knots from KMUO-KJER. Winds
aloft southwesterly 20-30 knots up through 10K feet MSL.
Weekend outlook...IFR/MVFR conditions in snow will continue Saturday
morning. A cold front and upper level trough will shift east over
the forecast area Saturday with snow ending over southeast Oregon
Saturday afternoon and decreasing over southwest Idaho Saturday
night. No precipitation expected Sunday, except widely scattered
snow showers over the central mountains of Idaho.
&&
.PREV DISCUSSION...
SHORT TERM...Tonight through Sunday...Winter weather advisories are
in effect through Saturday. A deepening upper level trough is
currently centered over the West Coast. The warm frontal band ahead
of the trough continues to produce snow across most of southwest
Idaho, while snow has ended at most locations in southeast Oregon.
Snow should taper off in southwest Idaho this evening, but increase
across the region late tonight through Saturday morning as the upper
level trough pushes inland. As the trough moves over our area
Saturday afternoon and evening, we can expect scattered snow showers
in the cold moist and unstable air, but little additional
accumulation is expected. Drier more stable northwest flow aloft on
Sunday will bring colder temperatures and partly cloudy skies, with
only a few flurries over the Idaho mountains.
LONG TERM...Sunday night through Friday. Northwesterly flow aloft
will briefly bring cold and dry conditions for Monday. Monday
morning will be one of the coldest mornings of the year. Another
trough with ample moisture will pass by with a cold front late
Tuesday into Wednesday bringing snow to most of the area. The West
Central Mountains of Idaho and Boise Mountains along with Baker
county will get the most snow from the system. Models differ greatly
after Wednesday with the ECMWF showing a high amplitude ridge and
the GFS showing cold northerly flow with a polar frontal passage
next Friday. There is not aloFt of confidence in either solution but
the drier EC solution is favored. Temperatures are expected to
remain below normal through the period.
&&
.BOI WATCHES/WARNINGS/ADVISORIES...
ID...Winter Weather Advisory until 11 AM MST Saturday
IDZ011>014-016-033.
Winter Weather Advisory until 5 PM MST Saturday IDZ015-029-030.
OR...Winter Weather Advisory until 11 AM MST /10 AM PST/ Saturday
ORZ062>064.
&&
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DISCUSSION...KB
AVIATION.....JA
PREV SHORT TERM...JT
PREV LONG TERM....JDS/WHThe national radar mosaic for the moment the first event began.
5 heavy snow. Local standard time, as filed.
The National Weather Service office in Boise recorded 5 inches of snow with reports from various sources around the area of 4 to 7 inches in the valley and up to 13 inches in the foothills.
COOP observers and trained spotters around Emmett, Payette and Weiser reported 6 to 9 inches of snow.
COOP observers and trained spotters around Emmett, Payette and Weiser reported 6 to 9 inches of snow.
Social media reported 10 to 15 inches of snow around Lowman and 12 inches at Prairie.
Social media reported 14 inches of snow at Fairfield.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Idaho in 2016Every state in 2016This day in weather historyWarnings in Idaho, December 2016
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: 671748, 671749, 671750, 671754, 671758.