A deep low passed well to the north, bringing high wind to the northwest interior and coast. The high wind extended south into the Seattle region.
Every event with a place to put it; 1 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 SEW wrote it up.
A deep low passed well to the north, bringing high wind to the northwest interior and coast. The high wind extended south into the Seattle region. The wind was not as strong in the Seattle area as it was on December 14--only 30,000 Seattle City Light customers were without power at the storm's peak. However, it was the strongest storm of the season so far in the northwest interior, where power outages were widespread, and some of the outages lasted nearly a week.
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 Seattle, WA wrote its last area forecast discussion before the first event at Dec 20, 3:14 AM PST, 2 hours 46 minutes earlier.
Area Forecast Discussion
National Weather Service Seattle WA
314 AM PST Thu Dec 20 2018
.SYNOPSIS...
The next system will affect western Washington today, with strong
wind and rain expected. A brief break is expected Friday and
Saturday with some light showers possible. The next storm system
will approach the coast Saturday night and Sunday, with rain
continuing Monday and Tuesday. Could see another break in the
constant activity by mid week next week.
&&
.SHORT TERM...
A somewhat broad area of cyclonic flow exists to the west of the
Washington and Oregon coastline this morning, with water vapor
satellite imagery revealing a developing cyclone within this
larger scale regime near 130W. This particular disturbance will
remain rather compact as it ejects NE into Vancouver Island later
this morning. There is a strong lower level reflection of this
developing wave, with a clear and tightly compact sfc low located
to the east of the main center of mid level low pressure, with a
warm front extending to the E/SE of the sfc low and a cold front
draped S of the low.
Warm front is beginning to move into western Washington and this
can be further confirmed by MRMS radar imagery where much more
widespread rain is seen moving onto the Washington coastline. The
warm front will continue to spread north across the state thru
the morning hours, leaving western Washington in the warm sector
in the boudnary's wake. Strong WAA advection will ensue in the
lower levels in this regime with the development of a strong LLJ
/50kt+ at 850mb/. This strong WAA should help raise snow levels
rather noticeably from 3000-4000ft range to well over 5000ft.
Winter Weather Advisory for the Cascades should be allowed to
expire at 18z today given less of a concern for heavy snowfall.
Until then could see some slick roadways in areas where snow is
falling. Perhaps the greatest concern today will be the wind, as
winds in the lower levels really pick up from west to east as the
warm front pulls north and the cold front makes its way towards
the coast. High Wind Warnings will remain valid for the coast and
the northern interior/Puget Sound vicinity with advisory criteria
outside of these areas for much of the remaining lowland
locations. Please refer to NPWSEW for more complete details but do
expect the potential for locations in the High Wind Warning to
see sustained winds of 25-40mph and gusts to 60mph or just above.
Power outages and downed trees will be the main impact during
periods of high wind. Later in the morning and into the afternoon,
the system's cold front will sweep through the area. Rain will
continue along with highest wind speeds until the front passes.
Although the main parent system will pull NE into southern BC from
Victoria Island, another quick moving shortwave trough will pass
across the area this evening and tonight, keeping rain chances up
and conditions breezy. Should finally see some clearing very late
tonight and into early Friday.
Weak mid level ridging will pass through the region on Friday.
This should keep things dry on a whole but a weak trough caught
underneath the ridge across Oregon could allow for a few showers.
The next weak system will approach the area Friday evening and
Friday night carrying with it another chance for rain all the way
into Saturday afternoon. This system still looks to break apart
somewhat as it moves inland as the next, potentially more
significant system quickly approaches the area.
Kovacik
.LONG TERM...
Another strong Pacific system is looking increasingly likely for
Saturday night and Sunday. Still too far out to really look into
specific impacts, but wind and rain seem plausible at this point.
Looking like little potential for a break as another system dives
south into western US coast vicinity for Christmas Eve and
Christmas Day, with rain remaining possible. Thereafter, high
pressure in the mid levels may try to build east towards the
PacNW, which may yield a break in the continuously active pattern.
Kovacik
&&
.AVIATION...A cold front will move through the area late this
morning and early this afternoon. Out ahead of the front ceilings in
the 3500-4500 foot range with local visibilities 3-5sm in moderate
rain. With and behind the front ceilings will lower to the 2000-3000
foot range. Surface winds increasing in the morning with locations
from Seattle northward gusting in the 35-45 knots 18z-00z. Low level
wind shear is possible for a few hours in the morning with the winds
around 2000 feet southerly 40-50 knots. Winds easing slowly behind
the front this afternoon into the evening hours.
KSEA...Ceilings 3500-4500 feet with light rain this morning.
Visibility lowering to 4 to 5sm by 18z. Winds at 2000 feet southerly
at 40-50 knots beginning at 15z and continuing into the middle of
the afternoon. Ceilings lowering with and behind the front this
afternoon to 2000-3000 feet. Surface winds increasing this morning
peaking at 25 knots gusting 40 knots 18z-23z. Southerly winds easing
slowly late this afternoon into the evening hours. Felton
.MARINE...A strong frontal system will move through the area
today. The front is associated with a deep low pressure center that
will reach the coast of central Vancouver Island late this m morning.
Storm warnings and and gale warnings are in effect as well as a
coastal flood warning for the coast and a coastal flood advisory for
the beaches and low lying areas along the northern inland waters.
The tidal anomaly due to low pressure will be 1-3 feet on the coast
and up to a foot for the northern inland waters.
&&
.HYDROLOGY...Flooding continues on the Skokomish river in Mason
County. Rain today will cause the river to rise again with moderate
flooding expected later this afternoon when the river crests.
Flooding on other rivers is not expected over the next seven
days.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...High Wind Warning from 10 AM this morning to 7 PM PST this
evening for Bellevue and Vicinity-Bremerton and Vicinity-
Hood Canal Area-Seattle and Vicinity-Tacoma Area.
Winter Weather Advisory until 10 AM PST this morning for
Cascades of Snohomish and King Counties-Cascades of Whatcom
and Skagit Counties.
Wind Advisory from 10 AM this morning to 7 PM PST this evening
for East Puget Sound Lowlands-Lower Chehalis Valley Area-
Southwest Interior.
High Wind Warning from 7 AM this morning to 7 PM PST this
evening for Admiralty Inlet Area-Everett and Vicinity-San
Juan County-Western Skagit County-Western Whatcom County.
Coastal Flood Advisory from 7 AM this morning to 2 PM PST this
afternoon for Admiralty Inlet Area-Eastern Strait of Juan
de Fuca-Everett and Vicinity-San Juan County-Western Skagit
County-Western Strait of Juan De Fuca-Western Whatcom
County.
High Wind Warning until 1 PM PST this afternoon for Central
Coast-North Coast.
Coastal Flood Warning from 7 AM this morning to 4 PM PST this
afternoon for Central Coast-North Coast.
Wind Advisory from noon today to 7 PM PST this evening for
Eastern Strait of Juan de Fuca.
PZ...Small Craft Advisory for rough bar until 4 PM PST Friday for
Grays Harbor Bar.
Storm Warning until 4 PM PST this afternoon for Coastal Waters
From Cape Flattery To James Island 10 To 60 Nm-Coastal
Waters From Cape Flattery To James Island Out 10 Nm-Coastal
Waters From James Island To Point Grenville 10 To 60 Nm-
Coastal Waters From James Island To Point Grenville Out 10
Nm-Coastal Waters From Point Grenville To Cape Shoalwater
10 To 60 Nm-Coastal Waters From Point Grenville To Cape
Shoalwater Out 10 Nm.
Storm Warning from 4 PM this afternoon to 4 AM PST Friday for
Central U.S. Waters Strait Of Juan De Fuca-East Entrance
U.S. Waters Strait Of Juan De Fuca.
Gale Warning until 4 PM PST this afternoon for Central U.S.
Waters Strait Of Juan De Fuca-East Entrance U.S. Waters
Strait Of Juan De Fuca.
Gale Warning until 4 AM PST Friday for Northern Inland Waters
Including The San Juan Islands-West Entrance U.S. Waters
Strait Of Juan De Fuca.
Gale Warning until 7 PM PST this evening for Admiralty Inlet.
Gale Warning until 10 PM PST this evening for Puget Sound and
Hood Canal.
&&
www.weather.gov/seattleThe national radar mosaic for the moment the first event began.
10 high wind. Local standard time, as filed.
The KHQM ASOS recorded 45 mph sustained wind, gusting to 62 mph, for several hours. WPT also recorded a 42 mph sustained wind.
Lopez Island recorded 41-51 mph sustained wind with 59 mph gusts.
Destruction Island had 50+ kt sustained wind for several hours. La Push recorded 40 mph sustained wind, gusting to 58 mph, for several hours.
The KBLI ASOS recorded 41 mph sustained wind, gusting to 62 mph. Sandy Point Shores had 41 mph sustained wind, gusting to 63 mph. Ferndale gusted up to 72 mph.
The ASOS at Shelton had 41 mph sustained wind.
The ASOS at KPAE had 43 mph sustained wind, gusting to 66 mph.
The ASOS on Whidbey Island (KNUW) recorded a 62 mph gust.
Anacortes recorded a 62 mph gust, and Blanchard had a 59 mph gust.
Indianola had a 58 mph gust.
The I-90 floating bridge had 43 mph sustained wind gusting to 55 mph, while the SR-520 floating bridge had 47 mph sustained wind gusting to 59 mph.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Washington in 2018Every state in 2018This day in weather historyWarnings in Washington, December 2018
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: 791062, 791065, 791061, 791063, 791067, 791066, 791060, 791064, 791068, 791069.