A strong low pressure system over the Gulf of Alaska brought a strong cold front through. This generated strong winds across southwest Washington, and also brought heavy rain which caused flooding on the Grays river.
Every event with a place to put it. 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 PQR wrote it up.
A strong low pressure system over the Gulf of Alaska brought a strong cold front through. This generated strong winds across southwest Washington, and also brought heavy rain which caused flooding on the Grays river. Large seas also caused damage in spots along beaches.
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 Portland, OR wrote its last area forecast discussion before the first event at Dec 17, 10:28 AM PST, 4 hours 32 minutes earlier.
Area Forecast Discussion
National Weather Service Portland OR
1028 AM PST Mon Dec 17 2018
.SYNOPSIS...After a few showers this morning, attention quickly turns
to a developing atmospheric river event that will bring heavy rain
tonight into Tuesday across much of SW Washington and NW Oregon.
Strong south winds will develop along the coast this afternoon as low
pressure approaches, then spread inland this evening. The strongest
winds and heaviest rain will occur overnight and into Tuesday morning
as a frontal zone moves slowly southward across the forecast area.
Active weather will continue through the end of the week, with
another frontal system expected to bring more rain and gusty winds
Thursday.
&&
.SHORT TERM...Today through Wednesday...Only update is to the
rainfall forecast section below...Water vapor satellite
imagery shows an elongated upper level trough pushing eastward into
the Pacific Northwest. Scattered showers offshore are presently
moving across the forecast area, but should decrease this morning as
temperatures warm aloft.
Looking out toward the Pacific, satellite water vapor imagery shows
an impressive atmospheric river taking shape from roughly 44N/137W
west-southwestward to roughly 31N/170W as of 09z, tapping into
moisture from the west-central Pacific tropics. Satellite-derived
winds suggest this atmospheric river is being powered by an
impressive 150-175 kt jet stream, with 100 kt-plus winds extending
down as far as 600-650 mb. This is resulting in high-end moisture
transport, even for December. 00z GEFS and GFS both show integrated
vapor transport (IVT) of over 1200 kg/ms, which is an impressive 4
standard deviations above normal for this time of year. 00z NAEFS
suggests IVT will decrease to around 750-850 kg/ms by the time the
core of this moisture plume makes landfall on the Oregon and south
Washington coast. However this is still 3-4 standard deviations above
normal, and climatology suggests this is the type of atmospheric
river that only returns during the month of December once every 5
years or so. So...confidence is increasing that this will be a
high-end rainfall event for our forecast area as the axis of the
atmospheric river makes landfall into SW Washington late this
afternoon then moves slowly south across the forecast area tonight
into early Tuesday. Weagle
Updated...
Atmospheric river with substantial IVT already discussed will linger
over western Oregon long enough to be considered a strong event with
substantial rainfall focused on the coast, coast range and the south
Washington and North Oregon Cascades. Based on past events of this
magnitude I have updated the rainfall forecast (QPF) to indicate
higher amounts than in previous forecast mainly over the North and
Central Coast range of Oregon and the Southwest Washington Cascades.
We will likely see amounts in excess of 2 inches/6hr at some of the
key locations in these areas such as Lees Camp and June lake. This
period of heaviest rain will have a duration of 12 to 18 hours.
Rainfall totals will be significant across the Coast and Willamette
Valley but lower than the coast range and southwest Washington
mountains. The valley could experience some urban or small stream
flooding later tonight and especially during the morning hours. We
could see some high rainfall rates as the front passes Tuesday
morning and this would result in some urban flooding and ponding on
roads.
We will be monitoring the Eagle Creek Burn area closely for rain
rates that could pose a problem for debris flows or debris laden
flash flooding, but it is uncertain at this time if anything
significant will happen. Schneider
No changes from previous discussion below...
One quick note about the Cascades...cool air leftover in eastern
Skamania County may result in a brief period of heavy snow there this
evening before snow levels quickly rise with the arrival of the
deeper subtropical air mass. The snow level in this area looks to
start out around 3000-4000 feet, but quickly rises to well above 5000
feet overnight. Given the brief nature of this burst of snow and the
fact that it will mainly impact wilderness areas, will waive the
issuance of any winter highlights for this area. Otherwise, snow
levels will remain well above the passes and likely most of the ski
resorts during the bulk of this event.
Meanwhile, strong southerly winds will feed into the front. Pressure
gradients along the coast are initially oriented rather offshore
this afternoon, but gradually open up late this afternoon into
this evening. This should allow high winds to surface along the
coast including the coastal communities and eventually into the Coast
Range as well. A potent coastal jet appears likely to the south of
the front, with the 00z/06z NAM continuing to suggest 850 mb winds on
the order of 75-85 kt and 65-75 kt winds as low as 950 mb. At this
point, it appears a safe bet that our beaches and headlands will gust
into the 70-80 mph range, with potentially damaging gusts of 60-70
mph reaching into some coastal communities. Would not be surprised if
a few of the windier spots such as Cape Meares, Cape Foulweather, and
Sea Lion Caves approach 90 mph during the peak of this event later
this evening and overnight. Exposed elevations of the Coast Range
will also approach 75 mph overnight. Strong winds will also affect
the highest elevations of the Cascades, with gusts possibly exceeding
100 mph for the highest elevations of Mount Hood as the core of the
jet stream passes overhead Tuesday. With the lack of a strong
cross-Cascades gradient, it appears winds will remain below the
warning criteria of 75 mph gusts for the passes and elevations below
6000 feet.
A fairly strong south-southeast to north-northwest pressure gradient
will also begin to develop across the Willamette Valley later this
afternoon through Tuesday morning. Areas to the south of the slowly
moving front stand to see gusts up to 50 mph, with some of the
exposed terrain such as the West Hills of Portland, Chehalem
Mountain, and the hills around Salem liable to see a few gusts up to
60 mph. Of note is the 00z ECMWF 10m wind gust forecast of 50-65 mph
throughout much of the Willamette Valley. This seems to be a bit too
strong, especially considering stabilization of the low-levels that
may occur as rain increases across the region. Will go ahead and
issue a Wind Advisory for the Willamette Valley zones, leaving Clark
County and points northward out of it as the strongest gradients
appear to be south of the Columbia River. There is a small chance
that, if more models start to look like the 00z ECMWF, that this Wind
Advisory may eventually need to be upgraded to a warning. We will
monitor this situation very closely and will update as needed.
Rain will taper to showers behind the front, with cooler air lowering
snow levels closer to the Cascade Passes by Wednesday morning. Models
do show some potential for convection in the cooler air mass behind
the front Tuesday, but with NAM lifted indices generally above 0 deg
C, will avoid adding thunder for now. Air mass stabilizes rather
quickly Tue night into Wed morning as the frontal zone begins to lift
northward as a much weaker warm front that is only likely to produce
light rain. Weagle
.LONG TERM...Wednesday night through Sunday...No changes. Previous
discussion follows...Will have a bit of a lull in the rain Wednesday
night as we sit between systems. Models are coming into better
agreement on the timing of the next system on Thursday. This system
will make landfall on the coast Thursday morning, spreading across SW
Washington and NW Oregon through midday. There is quite a bit of
moisture with this system, but it will be fairly fast as it moves
across the area. That means this will probably not put down a lot of
rain. The only issues it might create are on rivers that are still
elevated from the rain Monday-Tuesday. We will have another break in
the rain Friday and Saturday as high pressure moves over the area
between systems. The upper-level pattern is a little questionable for
completely dry conditions, so left chance PoPs for this time period
until we get closer. Sunday we will have another low pressure system
move in, bringing another round of rain across SW Washington and NW
Oregon.
Snow levels are up around 6000-7000 feet Wednesday night into
Thursday. Snow levels start to fall behind the front Thursday night,
dropping down to 2000-2500 feet by Friday morning. Unfortunately
this will be around the time the precipitation is winding down,
though there may be a period of decent snow in the Cascades Thursday
night as snow levels are dropping. There shouldn't be much moisture
with the lower snow levels that hold through Saturday, and then snow
levels start to rise again with the next system on Sunday. -McCoy
&&
.AVIATION...VFR continues across the region this morning, and
will continue into the afternoon, with increasing mid and high
clouds and cigs lowering to low VFR for the afternoon. Rain
should push to the coast by late afternoon, and inland this
evening. Meanwhile, southerly winds aloft increase this
afternoon as the front approaches, with strong southerly winds
down to the surface along the coast and over the higher terrain
by early evening. Gusts 55 to 70 kt expected for those areas,
with gusts 30 to 40 kt farther inland including the Willamette
Valley this evening and overnight. Expect widespread MVFR after
02Z along the coast, and inland after 06z with periods of lower
cigs/vsbys possible in steadier rain.
PDX AND APPROACHES...VFR today mid level clouds and lowering VFR
cigs through the afternoon. Rain at times tonight, but heavier
rain arrives later overnight/early Wednesday. East wind picks up
today, and continues into the evening. Increasing southerly flow
aloft will lead to developing low level win shear this evening.
Expect MVFR cigs after 08z through much of Tuesday. Cullen
&&
.MARINE...Southerly winds generally 15 to 25 kt this am, with
seas running at 20 to 22 ft. But, that will change today, as yet
another strong frontal system pushes into the region.
Strong front out near long 140W will push towards the Pac NW
today, but will slow as it approaches. Strong southerly pressure
gradients will develop over the region later today, and remain
tonight. Gusty southerly gales will develop this afternoon and
continue into this evening. But, models showing higher potential
for storm force winds for a time this evening into the overnight
hour. Will continue Marine Storm warning for tonight. Still think
that these stronger winds will be over the Oregon coastal waters
between 7 pm and 3 am, with peak gusts of 50 to 55 kt.
Front will stall over the waters tonight, as surface low develops
west of Oregon. This surface low will push inland early Tue,
dragging the front inland Tue am. Winds will ease from north to
south Tue am. Will still gust 25 to 35 kt Tue afternoon/evening.
Seas this am still dominated by the long period westerly swell,
running at 21 to 24 ft. This will continue to provide dangerous
surf conditions. As winds increase tonight, the wind generated
waves and base line swell will push overall seas up, generally 25
to 30 ft later this evening and overnight. Would not be
surprised to see seas top near 32 or 33 ft briefly along the
Oregon coast around midnight tonight.
There will be a lull between systems later Tue night through
Wed evening. Then will see another front arrive, with southerly
gales later Wed night into Thu. Rockey.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...Flood Watch from late tonight through Wednesday afternoon for
Central Coast Range of Western Oregon-Central Columbia
River Gorge-Central Oregon Coast-Central Willamette Valley-
Coast Range of Northwest Oregon-Greater Portland Metro
Area-Lower Columbia-North Oregon Coast-Northern Oregon
Cascade Foothills-Upper Hood River Valley-Western Columbia
River Gorge.
High Wind Warning until 6 AM PST Tuesday for Coast Range of
Northwest Oregon-North Oregon Coast.
High Surf Warning until 6 AM PST Tuesday for Central Oregon
Coast-North Oregon Coast.
High Wind Warning until noon PST Tuesday for Central Coast
Range of Western Oregon-Central Oregon Coast.
Wind Advisory from 4 PM this afternoon to noon PST Tuesday for
Central Willamette Valley-South Willamette Valley.
Wind Advisory from 6 PM this evening to 8 AM PST Tuesday for
Greater Portland Metro Area.
WA...Flood Watch from late tonight through Wednesday afternoon for
Central Columbia River Gorge-Greater Vancouver Area-I-5
Corridor in Cowlitz County-South Washington Cascade
Foothills-South Washington Coast-Western Columbia River
Gorge-Willapa Hills.
High Wind Warning until 6 AM PST Tuesday for South Washington
Coast-Willapa Hills.
High Surf Warning until 6 AM PST Tuesday for South Washington
Coast.
PZ...Storm Warning from 3 PM this afternoon to 5 AM PST Tuesday for
Coastal Waters from Cape Shoalwater WA to Cascade Head OR
out 60 NM.
Gale Warning until 3 PM PST this afternoon for Coastal Waters
from Cape Shoalwater WA to Florence OR out 60 NM.
Storm Warning from 3 PM this afternoon to 10 AM PST Tuesday for
Coastal Waters from Cascade Head OR to Florence OR out 60
NM.
Small Craft Advisory for Rough Columbia River Bar until 6 PM
PST Tuesday.
&&
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...Flood Watch from late tonight through Wed afternoon for
much of northwest Oregon.
High Wind Warning for this afternoon til 6 am Tue for...
North Oregon Coast
Coast Range of Northwest Oregon.
High Wind Warning for this afternoon til noon Tue for...
Oregon Central Coast
Central Coast Range of Western Oregon.
High Surf Warning today through tonight for...
North Oregon Coast
Oregon Central Coast.
WA...Flood Watch from late tonight through Wed afternoon for
much of southwest Washington.
High Wind Warning from noon today to 6 AM Tue for...
South Washington Coast
Willapa Hills.
High Surf Warning today trough tonight for...
South Washington Coast.
PZ...Gale Warning today on all coastal waters.
Storm Warning from 3 pm today to 5 am Tue for coastal
waters from Cape Shoalwater to Cascade Head out 60 nm.
Storm Warning from 3 pm today to 10 am Tue for coastal
waters from Cascade Head to Florence, out 60 nm.
Small Craft Advisory for Rough Columbia River Bar
conditions today through Tue afternoon.
&&
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This discussion is for Northwest Oregon and Southwest Washington
from the Cascade crest to 60 nautical miles offshore. This area is
commonly referred to as the forecast area.The national radar mosaic for the moment the first event began.
2 high wind, 1 flood. Local standard time, as filed.
A weather station on Cape Disappointment recorded wind gusts up to 68 mph. Another weather station on Megler Bridge recorded wind gusts up to 65 mph. Toke Point RAWS also recorded sustained winds up to 44 mph.
Abernathy RAWS recorded wind gusts up to 61 mph.
The Grays River near Rosburg crested at 13.2 feet around 11:30 AM, which is 1.2 feet above flood stage. No damage was reported.
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: 799079, 799080, 799092.