A very moist front sagged south over southwest Washington, and stayed in place for much of the day on April 14th. Heavy rain in the area of the Grays River led the river to rise above flood stage.
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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 very moist front sagged south over southwest Washington, and stayed in place for much of the day on April 14th. Heavy rain in the area of the Grays River led the river to rise above flood stage.
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 Apr 14, 8:02 PM PST, 28 minutes earlier.
Area Forecast Discussion...UPDATED
National Weather Service Portland OR
902 PM PDT Sat Apr 14 2018
Updated Aviation and Marine sections
.SYNOPSIS...A quasi-stationary cold front has been producing heavy
rain and high elevations snow over extreme SW Washington today. This
front will slowly move inland late tonight and Sunday spreading the
heavy rain south and east, and snow to the Oregon Cascades. The front
will finally move east of the Cascades Monday morning, but onshore
flow will continue showers through Tuesday. Another upper level
trough is expected Wednesday with possibly dry weather Thursday and
Friday.
&&
.SHORT TERM...Today through Tuesday...A stationary front has lifted
north a tad late this morning continuing rain for extreme SW
Washington and extreme NW Oregon. Areas outside this region have
been mostly dry, but that will change tonight as a low moves along
the baroclinic zone. The persistent rain over the Willapa Hills has
resulted in rises of the Naselle, The Willapa and the Grays River.
The Grays River has been rising fairly rapidly near Rosburg, and is
now forecast to rise above flood stage around 9 PM tonight, and a
Flood Waring has been issued.
Snow levels are 4500 to 5000 feet, but the only area currently seeing
any precipitation at these elevations is the South Washington
Cascades, where there is an active Winter Weather Advisory.
A low moving along the baroclinic zone will push the baroclinic zone
further inland tonight and rain will spread further south and east,
but the front will not move inland until Sunday afternoon, and not
fully depart the area until Monday morning. The band of heavier rain
that is currently across SW Washington will shift south late tonight
and Sunday morning, then move inland Sunday afternoon.
As the precipitation moves inland late tonight and Sunday snow will
begin to accumulate over the Oregon Cascades near and above 4500
feet. he QPF will initially be fairly light with rates around 0.10
every 3 hours which translates to around 1 to 2 inches of snow every
6 hours which is just under our winter weather criteria. However, the
rates may increase Sunday night and Monday morning as the front moves
over the Cascades with lowering snow levels possibly causing
increasing travel impacts for the Cascade passes.
Cooler air aloft associated with an upper low will result in snow
levels lowering down to around 2500-3000 feet Sunday night and
Monday. The upper low will also increase instability over the region
for the potential of deeper convection, and possibly some
thunderstorms. The best chance for thunderstorms is on the coast and
coast range late Sunday night into Monday morning, then pushing
inland Monday afternoon.
Moist onshore flow continues showers Monday night and Tuesday with
snow levels remaining between 2500 and 3000 feet. ~TJ
.LONG TERM...Tuesday night through Saturday...Weak onshore flow,
combined with left over moisture keeps a chance of rain in the
forecast Tues night into Wed. Snow levels between 2800 and 3200 ft.
The next trough and associated front works its way into our area Wed
night and into Thur morning. The models are in some disagreement on
the characteristics of the system. The GFS looks like a col, while
the Euro shows a splitting trough. Depending on what happens will
dictate how much moisture will move in with the system on Wed night.
After the trough passes a ridge sets up on Fri, which looks to bring
a drying trend through Sat. The models are currently in agreement on
this drying trend. As a result temperatures are warming closer to
our seasonal normals. -42
&&
.AVIATION...A front moving slowly south and east overnight will
spread rain and MVFR cigs inland overnight, roughly starting
around 08Z-10Z inland and lasting through most of the day Sunday.
Coastal areas should have a mix of VFR and MVFR behind the front
overnight and Sunday. A weak low will move along the front
overnight into Sun morning, likely causing the front to stall
over the lowlands through around midday Sun. Expect mainly MVFR
conditions and steady rain during this time. Conditions may trend
toward more VFR late Sunday afternoon or evening as the front
gradually dissipates.
KPDX AND APPROACHES...Mainly VFR conditions through about 08Z
then expect increasing rain and MVFR cigs a front moves onshore.
Expect the front to linger over the region through most of Sun
morning, with predominantly MVFR conditions during this time.
/mh Pyle
&&
.MARINE...A frontal boundary is near the north coast and is
expected to move ashore shortly. It will take a few hours more for
the front to move ashore for the central marine zones. Winds will
quickly ease and switch to west or northwest behind the front. The
front will stall over the south Oregon coastal waters overnight then
another frontal wave lifts the front north on Sunday. The frontal
wave should move ashore near Florence or south of Florence midday
Sunday, but winds should remain N-NW over the waters.
Another low will form over Vancouver Island on Mon, which
combined with building high pres over the NE Pac, will bring a
period of gusty NW winds to the waters from early Mon through
early Tue. Weak high pres will briefly move over the waters Tue,
beginning a period of relatively benign weather that may last
through much of the second half of next week.
Seas will generally remain around 11 to 13 ft tonight into Sun
morning. They may briefly drop below 10 ft late Sun, but
increasing NW winds will likely push them back into the low teens
by Mon. Seas should drop below 10 ft by late Tue, and should
remain well below 10 ft through the rest of the week. /mh Pyle
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...Winter Weather Advisory until 8 AM PDT Tuesday for South
Washington Cascades.
PZ...Small Craft Advisory for hazardous seas until 5 PM PDT Sunday
for Coastal Waters from Cape Shoalwater WA to Florence OR
out 60 NM.
Small Craft Advisory for winds until 1 AM PDT Sunday for
Coastal Waters from Cascade Head OR to Florence OR out 60
NM.
Small Craft Advisory for Rough Columbia River Bar from 2 AM to
8 AM PDT Sunday.
Small Craft Advisory for Rough Columbia River Bar from 3 PM to
7 PM PDT Sunday.
&&
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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 CWA or forecast area.The national radar mosaic for the moment the first event began.
1 flood. Local standard time, as filed.
The Grays River near Rosburg crested at 12.6 feet around 1 AM, which is 0.6 foot 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, April 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: 760876.