From the evening of December 18th through the morning of December 20th a deep fetch of Pacific moisture was directed into the region. This moisture enhanced along a warm front and produced heavy snow across the mountains of eastern Washington.
Every event with a place to put it; 17 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 OTX wrote it up.
From the evening of December 18th through the morning of December 20th a deep fetch of Pacific moisture was directed into the region. This moisture enhanced along a warm front and produced heavy snow across the mountains of eastern Washington. In the lower elevations the warm front quickly raised snow levels over the eastern Columbia Basin and the valleys of north Idaho limiting snow accumulations to 1 to 3 inches before changing over to rain. In the western Columbia Basin cold air dammed against the Cascades was slow to scrub out and precipitation remained as snow for a longer period resulting in heavy accumulations in the Wenatchee area, the Waterville Plateau and the Okanogan Valley.
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 Spokane, WA wrote its last area forecast discussion before the first event at Dec 18, 3:58 AM PST, 6 hours 2 minutes earlier.
Area Forecast Discussion
National Weather Service Spokane WA
358 AM PST Wed Dec 18 2019
.SYNOPSIS...
A big winter storm will spread snow across eastern Washington and
north Idaho beginning Wednesday night. Periods of rain and snow
are expected to continue Thursday into Friday. The East Slopes of
the Cascades will likely receive heavy snow accumulations, and the
passes in central Washington could receive several feet of snow
by the weekend. Mild temperatures and light mountain snow is
expected Saturday and Sunday.
&&
.DISCUSSION...
Today...The ridge continues to bend down this morning as the upper
level low begins to move into the eastern Pacific. Radar has been
picking up on some light returns over the northeast Washington
mountains and it looks like Colville got dusted with light snow
over the last hour. A mid level shortwave and weak isentropic lift
tapped into the mid level cloud deck and is resulting in light
snow. This wave will move northeast through the region through
about 15z, so I added some chance pops for light snow up in that
area. Otherwise we expect increasing mid and high level clouds
today. Model guidance is very similar showing the warm over-
running precipitation with the next storm system has slowed done
by 6-12 hours. Consensus from neighboring offices will be to slow
down the onset of the precipitation until later this afternoon. So
now the forecast has just a chance of light snow to the crest of
the Cascades around 00z.
...A strong winter storm system will bring a variety of
precipitation to the entire region tonight through the rest of
the week...
Tonight and Thursday...The well advertised winter storm will move
through in two parts. The first weaker wave will move into the
region tonight and be east of the area by Thursday evening. As
mentioned in previous discussion an atmospheric river will be
pointed right at the Pac NW increasing the moisture to well over
200 percent of normal. With this much moisture moving into the
region it doesn't take much of a lifting process to kick off light
to moderate precipitation. That will be accomplished by warm front
moving into the region after 03, followed by a weak cold front
moving along the Canadian border. The cold front will result in a
brief break in the precipitation, before the next warm front moves
into the region Thursday evening. South to southwest flow at the
mid levels will shadow out the basin somewhat but the strength of
the warm front will overwhelm the shadow effect, so even the basin
is expecting some light to moderate precipitation. Precipitation
will be a wintry mix with snow, rain, and pockets of freezing rain
expected. An inch or two of snow will be possible for the lower
elevations, with 3-7 inches in the Cascades, the northeast
Washington mountains and the Idaho Panhandle mountains. Add in
light freezing rain and the travel impacts will be high. As such,
winter highlights have been issued and those will be updated as
necessary. Tobin
Thursday night through Tuesday:
An atmospheric river streaming substantial moisture into the
Pacific Northwest keeps heavy snow falling over most of Eastern
Washington and North Idaho. The leading edge of the atmospheric
river sweeps a warm and moist frontal zone initially Thursday
night allowing the warming trend to continue with the features
focus of moisture into the region which causes maximum
temperatures to peak in or abouts the Friday/Saturday time,
especially as the moisture plume becomes more south to north
oriented into Saturday. In addition the upper level jet being
pretty much directly overhead or within very close proximity
allows for brisk/breezy southerly component to the wind Thursday
night on thru Saturday. Saturday night into Sunday inflection
points downstream near California start to spin up and divert much
of the moisture so the remnants of the far east edge of the trof
over Northeast Washington and North Idaho don't get nearly as much
moisture steered into them, and by that time the cooler and
conditionally unstable airmass on the northwest side of the
remnant boundary has moved over a good portion of Eastern
Washington, therefore pops throttle back a bit over lowland and
valley locations between the lee of the Cascades and North Idaho
Saturday night into Sunday, keeping in mind the unstable airmass
could very well continue to support snow showers, only not to as
an intense degree in comparison to Thursday night thru Saturday.
Monday and Tuesday appear quite benign in comparison to this weeks
weather pattern with a general split flow in the trof over the
region suggesting the bulk of the moisture and energy will be
impacting locations well south of the region, however minor
disturbances could kick off some light activity running up from
the southwest so minor pops remain. In addition the cool trof
lingering overhead supports the slight cooldown in temperatures
starting Sunday and continuing into Tuesday. It should be noted
rises on most of the area rivers are expected heading into the
weekend due to the wet and warm conditions which would include the
Stehekin, Little Spokane, Paradise Creek, Hangman Creek, etc...
/Pelatti
&&
.AVIATION...
12Z TAFS: Mid and upper level moisture will stream into the region
this morning ahead of a storm system expected tonight. KEAT/KMWH
will have the challenging TAFs as there is plenty of boundary
layer moisture around and combined with light southeast-south
flow cigs will likely bounce between VFR/MVFR through 16z then mix
out. The storm tonight has slowed down by 6 hours or so, but
expect cigs to begin lowering for KEAT/KMWH around 00z with
precipitaiton beginning 07-08z. Precipitaiton will be as -sn at
KEAT and -sn/-fzra at KMWH. For KGEG/KSFF/KCOE/KPUW/KLWS
precipitation is not expected until after 10z and will be -sn with
conditions dropping to MVFR/IFR cigs/vsby. Tobin
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 36 28 35 33 45 39 / 0 70 60 90 80 80
Coeur d'Alene 38 28 36 34 43 39 / 0 60 70 100 90 80
Pullman 38 28 37 35 46 40 / 0 60 60 80 60 40
Lewiston 40 31 42 37 49 42 / 0 40 60 70 40 40
Colville 35 26 36 30 45 37 / 30 70 40 100 90 90
Sandpoint 36 27 35 32 42 38 / 0 60 80 100 100 90
Kellogg 38 27 36 34 42 39 / 0 50 80 90 90 80
Moses Lake 33 25 35 30 48 38 / 0 50 60 90 50 50
Wenatchee 31 24 32 29 40 35 / 10 60 60 90 80 70
Omak 33 25 32 30 40 36 / 0 60 40 90 80 70
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...Winter Storm Watch from Thursday morning through Friday morning
for Central Panhandle Mountains-Northern Panhandle.
WA...Winter Storm Watch from Thursday afternoon through Friday
morning for Okanogan Valley-Waterville Plateau-Wenatchee
Area.
Winter Storm Warning from 4 PM this afternoon to 4 AM PST Friday
for East Slopes Northern Cascades.
Winter Storm Watch from Thursday afternoon through Friday
morning for Northeast Mountains-Okanogan Highlands.
&&Hazardous Weather Outlook...UPDATED National Weather Service Spokane WA 536 AM PST Wed Dec 18 2019 IDZ001-004-WAZ037-038-041>043-191400- Northern Panhandle-Central Panhandle Mountains- Northeast Mountains-Okanogan Highlands-Wenatchee Area- East Slopes Northern Cascades-Okanogan Valley- 536 AM PST Wed Dec 18 2019 This Hazardous Weather Outlook is for portions of North Idaho... North Central Washington and Northeast Washington. .DAY ONE...TODAY No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...TONIGHT THROUGH TUESDAY Heavy snow will be likely Tonight through Friday night over the Cascades and the mountains of northeast Washington and north Idaho. Snow will likely be measured in feet rather than inches in the mountains by the weekend. This will result in treacherous travel over mountain passes. Moderate snow will also be possible across the valleys during this time. Mountain snow will continue into the weekend. IDZ002-003-026-027-WAZ031>036-044-191400- Coeur d'Alene Area-Idaho Palouse-Lewiston Area- Lewis and Southern Nez Perce Counties-Northeast Blue Mountains- Lower Garfield and Asotin Counties-Washington Palouse- Moses Lake Area-Upper Columbia Basin-Spokane Area- Waterville Plateau- 536 AM PST Wed Dec 18 2019 This Hazardous Weather Outlook is for portions of North Idaho... North Central Idaho...Central Washington...East Central Washington...Northeast Washington and Southeast Washington. .DAY ONE...TODAY No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...TONIGHT THROUGH TUESDAY Moderate snow will be possible across much of the region Tonight into Thursday. Pockets of light freezing rain will also be possible during this timeframe.
The national radar mosaic for the moment the first event began.
27 heavy snow. Local standard time, as filed.
A weather spotter in Omak reported 5.0 inches of new snow accumulation.
A member of the public in Okanogan reported 6.0 inches of new snow accumulation from this storm.
A member of the public in 4 miles southeast of Okanogan reported 7.5 inches of new snow accumulation from this storm.
A member of the public 7 miles south of Molson reported 4.0 inches of new snow accumulation from this storm.
The COOP observer at Holden Village recorded 38.5 inches of new snow accumulation from this storm system. Residual upslope snow showers slopping over the Cascade crest in the 24 hours after the main storm ended produced a further 10.5 inches of snow accumulation.
The COOP observer at the Leavenworth Fish Hatchery recorded 17.3 inches of new snow accumulation from this storm.
The COOP observer at Mazama recorded 19.1 inches of new snow accumulation from this storm.
The COOP observer at Plain recorded 13.8 inches of new snow accumulation from this storm.
The COOP observer at Stehekin recorded 43.0 inches of new snow accumulation from this storm. Residual westerly flow upslope snow showers slopping over the Cascade crest produced a further 6.0 inches in the 24 hours after the main storm ended.
The COOP observer at Winthrop recorded 6.7 inches of new snow accumulation from this storm.
An observer 5 miles southwest of Peshastin recorded 20.0 inches of new snow accumulation from this storm.
An observer at Lake Wenatchee recorded 17.0 inches of new snow accumulation from this storm.
An observer at Twisp recorded 6.0 inches of new snow accumulation from this storm.
A member of the public 4 miles southwest of Telma reported 28.0 inches of snow accumulation from this storm.
A member of the public 2 miles north of East Wenatchee reported 6.0 inches of new snow accumulation.
An observer at Boyds recorded 4.1 inches of new snow accumulation from this storm.
A member of the public in Deer Park reported 5.0 inches of new snow accumulation from this storm.
A member of the public in Usk reported 7.0 inches of new snow accumulation from this storm.
The COOP observer in Newport recorded 4.0 inches of new snow accumulation from this storm.
An observer in Metaline Falls reported 5.0 inches of new snow accumulation from this storm.
An observer in Evans reported 4.3 inches of new snow accumulation from this storm.
The 49 North Ski Resort reported 8 inches of new snow accumulation from this storm.
An observer in the city of Wenatchee recorded 5.6 inches of new snow accumulation from this storm.
An observer in the city of Wenatchee recorded 5.1 inches of new snow accumulation from this storm.
The COOP observer at the Entiat Fish Hatchery recorded 6.1 inches of new snow accumulation from this storm.
A member of the public 8 miles west of Cashmere reported 8.0 inches of new snow accumulation from this storm.
A weather spotter in Entiat reported 6.0 inches of new snow accumulation from this storm.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Washington in 2019Every state in 2019This day in weather historyWarnings in Washington, December 2019
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: 868290, 868292, 868294, 868296, 868275, 868276, 868277, 868278, 868279, 868280, 868281, 868282, 868283, 868295, 868297, 868312, 868293, 868298, 868301, 868304, 868308, 868319, 868285, 868286, 868287, 868289, 868291.