An atmospheric river event across the Pacific Northwest brought|deeper subtropical Pacific moisture as cyclonic flow remained present over the Gulf of Alaska and high pressure remained centered offshore southern California. Near the surface, a stationary boundary was draped from southern BC through the NW tip of |the Olympic Peninsula.
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.
An atmospheric river event across the Pacific Northwest brought|deeper subtropical Pacific moisture as cyclonic flow remained present over the Gulf of Alaska and high pressure remained centered offshore southern California. Near the surface, a stationary boundary was draped from southern BC through the NW tip of |the Olympic Peninsula. A shortwave trough rounded the base of the broader cyclonic flow over the Pacific and helped induce a surface wave along the stationary frontal |boundary, which brought both a flood and wind threat to Western Washington. As the sfc wave/low deepened, south winds strengthened across the entire area, with power outages and downed trees likely. More specifically, a High Wind Warning was in effect for the Everett, Admiralty Inlet, and Western Skagit County areas. West winds of up to 60 mph|were forecast and were expected to have the potential to produce significant |tree and powerline damage. A Wind Advisory was in place for much of the rest of the area.
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 Nov 14, 9:27 AM PST, 5 hours 33 minutes earlier.
Area Forecast Discussion
National Weather Service Seattle WA
927 AM PST Sun Nov 14 2021
.UPDATE...Rain this morning is steadiest across far northern areas
towards Whatcom County/northern Olympics and into BC with lighter
shower activity across the lowlands. Heaviest rain will be in that
area today into this evening. The bulk of the precipitation will
slide south with the front Monday morning-afternoon. Breezy winds
will be strongest Monday morning with the front.
&&
.SYNOPSIS...An atmospheric river will continue to affect the area
today, bringing wind and heavy rainfall. A river flood, landslide,
and power outage/downed tree threat will exist today and will
carry into Monday as the system then passes through the area. Snow
levels will lower Monday night into Tuesday with scattered
lowland showers and mountain snow likely for the area. Drier
weather Tuesday and Wednesday before the potential for another
strong system towards the end of the week.
&&
.SHORT TERM /TODAY THROUGH TUESDAY/...Cyclonic flow continues over
the Gulf of Alaska and just to the south over the NE Pacific,
while high pressure remains centered off the CA Coast. These
features place the stronger belt of westerlies/jet stream over the
far NE Pacific and into the PNW, while downstream a rather deep
trough remains the primary weather influence east of the Rockies.
At the surface, a warm front is lifting over WA, with associated
cyclone noted around the northern tip of Vancouver Island and a
cold front draped to its S/SW over the open Pacific. High pressure
then remains the dominant influence over most of the Western US.
Rain has returned over W WA as of yesterday afternoon and evening,
and as of 3AM still remains rather widespread across the area.
Per radar and MRMS imagery, it appears the heaviest and most
widespread precipitation is located across far southern BC and
Vancouver Island, along and north of the warm frontal boundary.
Very strong frontogenesis and WAA have been noted per SPC
mesoanalysis with this warm front, and this is helping contribute
to heavy rainfall development and maintenance along and around
its boundary, provided the absence of sufficient mid and upper
level support. Going forward through the day today, the warm front
is expected to remain to the north of the majority of the local
area, placing us in the warm sector of the front system. Continued
WAA and a heavily subtropical Pacific moisture influence will
help sustain widespread rain/shower development over the local
area for much of the day today, pockets of which will be moderate
to heavy at times. Can generally expect 2-4 inches over the higher
terrain (higher in the N Cascades closer to the frontal boundary)
and 0.5-1.0 inches in the lowlands (southern counties/S Cascades
may not receive much rain today). As this is occurring through
the day today, upstream over the Pacific, a mid level shortwave
trough located to the south of the more compact cyclonic flow over
the Gulf of Alaska will help induce sfc wave development along
the pre-existing cold front. As the short wave then progresses
east towards the local area this afternoon and evening, the
frontal system as a whole should begin to shift south from BC into
northern portions of W WA. As this occurs, expect heavy rainfall
to begin to affect the north coast, Olympics, and N Cascades.
There is also growing concern that the newly developed sfc waves
along the cold front will help enhance subtropical Pacific
moisture advection into the region. The potential for very heavy
rainfall will exist this evening and through Monday morning,
particularly for the locations just mentioned. If this does
verify, significant river flooding is highly likely across Whatcom
and Skagit Counties. Urban and smaller stream flooding may also
be an issue and this will need to be kept in mind for the Monday
morning commute.
The front will take some time to pass through the area on Monday,
exacerbating the river flooding and heavy rainfall concern, esp in
the Olympics and Whatcom/Skagit counties. Expect a very wet day
for Monday given the current model guidance, especially during the
morning and afternoon hours. Generally in this timeframe several
additional inches of rain are possible in the mountains and over
an inch is possible in the lowlands. Precipitation will become
more showery in the wake of the front, with snow levels dropping
rapidly. Snow levels will be around 7000 ft Monday afternoon and
will fall below 2000 ft by midnight Tuesday. This will raise
concern for mountain snow accumulation, particularly the Passes.
Precipitation does not appear very impressive, so snow amounts
have come down some over the last few forecast updates, with 2-4
inches possible. A PSCZ is also highly likely, and this will need
to be monitored for additional rainfall around the Sound and any
enhancements to mountain snow in the Passes. Conditions will dry
thru the day Tuesday with highs in the lowlands struggling to
reach 50.
Also of note with the AR system is the wind. A Wind Advisory is in
place for the coast and north interior thru 4pm, and this may need
to be extended in time. Elsewhere, southerly wind will be
noticeable through the day, with some gusts likely. Winds are
likely to be breezy through Monday and perhaps even into Tuesday.
Given the saturated soils, power outages and downed trees will
pose a threat, esp in areas within in the wind advisory.
Additional rainfall amounts from Sunday morning through Monday
evening of 4-6 inches in the Olympics and N & C Cascades (locally
higher), with 1-2 inches for the lowlands and S Cascades
possible. This will be in addition to the already 1-3 inches in
the Olympic and N Cascades and 0.5-2 inches the lowlands and C & S
Cascades over the last 24 hours.
Kovacik
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...The long term forecast
period will begin by giving the PNW a break from the active
weather as a weak upper level ridge moves in and high pressure is
dominant at the surface. Some sun is expected, but some moisture
may be moving in ahead of the next system. A cold morning is
expected, with lows in the low to mid 30s. High will again
struggle to reach to reach 50 and probably will top off a degree
or two cooler than Tuesday. Snow levels will be quite low as well,
under 1000 ft.
The next system should then approach the area for Thursday, and
may warrant watching. This system will be responsible for the
next round of rain and wind, but at least does not appear to have
the subtropical Pacific influence. Unsettled weather then appears
likely to close out the week and carry into the weekend.
Kovacik
&&
.AVIATION...A stalled frontal boundary lies just north of the
Canadian border this morning with strong westerly flow aloft and
gusty southerly winds near the surface. The air mass is very moist
and stable. Widespread MVFR and areas of IFR in light to moderate
rain will continue through the day, overnight, and into Monday
morning. Very gusty surface winds will persist into Monday. Low
level winds just above the surface will remain quite strong...S/SW
45 to 60 knots between 2000 and 5000 feet.
KSEA...Predominantly low MVFR conditions expected through the day and
into tonight with light rain at times. Surface winds to remain gusty
out of the S/SW 15 to 25 knots through this afternoon. Speeds likely
to increase early Monday morning ahead of an approaching cold front
with some gusts of 30 to 40 knots possible 12Z-18Z. May also
consider some LLWS in the forecast...in particular this
evening...with S/SW winds of 40-45 knots down to 2000 feet. 27
&&
.MARINE...Gale warnings in effect for all waters into Monday. There
may be something of lull in winds this afternoon, but confidence
remains rather high that winds will increase regionwide tonight and
become rather strong in the vicinity of a cold front as it moves
onshore around midday Monday. Models remain adamant that a strong
westerly surge will follow the front...which has prompted a storm
watch for the east entrance to the strait. In addition, the
formation of a meso-low in the lee of the Olympics on Monday
followed by impressive pressure rises will be a driving force for
widespread gale force winds over the interior waters Monday
afternoon.
High pressure will rebuild across the waters Tuesday into Wednesday
allowing winds to relax and seas to subside. 27
&&
.HYDROLOGY...Rivers are starting to rise from last night's first
round of rain. As the second batch of heavy rains starts moving
south out of Canada, persistent moderate to heavy rainfall will
affect the region through Monday. This event is directed towards
northwestern WA into southern BC and will once again result in
fairly widespread river flooding for rivers originating from the
Olympics, and central/northern Cascades. For several rivers,
particularly those originating from the north Cascades, the crests
with this second event are likely to be higher than those of the
previous AR event.
Some uncertainty remains regarding river level peaks in basins from
southern King County southward - as there is expected to be a sharp
drop off in rainfall along the periphery of the moisture band. Heavy
rainfall rates approaching 0.5-1"/hr at times will make urban
flooding a threat through Monday evening. In addition, the risk of
landslides will once again remain high beginning tonight and
persisting through at least Tuesday due to heavy rainfall and
strong, gusty winds that will make area bluffs unstable.
Pullin/Bower
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Flood Watch through Tuesday afternoon for Admiralty Inlet Area-
Bellevue and Vicinity-Cascades of Pierce and Lewis Counties-
Cascades of Snohomish and King Counties-Cascades of Whatcom
and Skagit Counties-Central Coast-East Puget Sound Lowlands-
Eastern Strait of Juan de Fuca-Everett and Vicinity-Hood
Canal Area-Lower Chehalis Valley Area-North Coast-Olympics-
Seattle and Vicinity-Tacoma Area-Western Skagit County-
Western Strait of Juan De Fuca-Western Whatcom County.
Wind Advisory until noon PST Monday for Bremerton and Vicinity-
Hood Canal Area-Seattle and Vicinity-Southwest Interior-
Tacoma Area.
Wind Advisory until 4 PM PST this afternoon for Admiralty Inlet
Area-Everett and Vicinity-San Juan County-Western Skagit
County-Western Whatcom County.
Wind Advisory until 4 PM PST Monday for Central Coast-North
Coast.
PZ...Small Craft Advisory until 7 PM PST Monday for Grays Harbor Bar.
Gale Warning until 4 AM PST Tuesday 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 Watch from Monday morning through Monday evening for East
Entrance U.S. Waters Strait Of Juan De Fuca.
Gale Warning until 10 AM PST Monday for East Entrance U.S.
Waters Strait Of Juan De Fuca.
Gale Warning until 4 PM PST Monday for Admiralty Inlet-Northern
Inland Waters Including The San Juan Islands-Puget Sound
and Hood Canal.
Gale Warning until 7 PM PST Monday for Central U.S. Waters
Strait Of Juan De Fuca-West Entrance U.S. Waters Strait Of
Juan De Fuca.
&&
www.weather.gov/seattle2 high wind, 1 strong wind. Local standard time, as filed.
Strong winds caused trees to come down and block US 101 during the evening hours of November 14.
Strong winds caused the fairgrounds, which hosted a COVID testing, in Skagit County to be closed as of 0845am on the 15th.
Around 0200L on November 15th, strong winds caused trees to fall across Western Whatcom County, blocking all of I-5 near MP 246 for a period of time.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Washington in 2021Every state in 2021This day in weather historyWarnings in Washington, November 2021
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: 994550, 994548, 994549.