Low pressure system moving into NW Washington and Vancouver Island feed lots of moisture into Northwest Oregon. This meant heavy snow in the North Oregon Cascades.
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.
Low pressure system moving into NW Washington and Vancouver Island feed lots of moisture into Northwest Oregon. This meant heavy snow in the North Oregon Cascades.
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 7, 1:49 PM PST, 3 hours 11 minutes earlier.
Area Forecast Discussion
National Weather Service Portland OR
249 PM PDT Sat Apr 7 2018
.SYNOPSIS...An occluded front associated with a strong Pacific storm
moved through southwest Washington and northwest Oregon early this
morning with a burst of modest wind and brief heavy rain. What is
called the bent back occlusion around the center of the deep low was
spreading onshore this afternoon with stronger wind and showers that
may turn to more steady rain overnight tonight. The wind will also
continue overnight tonight and into Sunday morning before the low
moves onshore around the southern tip of Vancouver Island late
tonight and inland and weakens as it moves eastward on Sunday. Some
thunder is possible this afternoon and early evening. Snow levels
will be lowering today and tonight and Sunday to a bit below the
Cascade passes, with heavy snow in the Cascades especially tonight
and Sunday. Another strong storm with more wind is expected Tuesday.
Additional unsettled weather is expected at times during the latter
part of next week.
&&
.SHORT TERM...Tonight through Tuesday...A fairly strong occluded
front moved onshore and eastward across southwest Washington and
northwest Oregon this morning with a modest burst of wind and some
locally heavy rain. The front was occluded and the gradient tended to
have a decent easterly component, limiting the strength of the wind
and keep the stronger winds aloft. There was a good burst of rain
associated with the frontal passage. Snow levels were falling behind
the passage of the front, as evidenced by temperature falls at the
RAWS sites earlier this morning.
Of more importance has been the bent back occlusion band or curl of
clouds around the deep surface low that has moved onshore during the
day today, with another stronger burst of wind both at the coast and
inland. With the low remaining off the coast through the night
tonight, moving onshore near the southern tip of Vancouver Island
late tonight, and then moving inland and eastward as it weakens
during the day Sunday, the strong winds will continue tonight into
Sunday morning before weakening.
This bent back occlusion will bring some substantial rainfall to the
forecast area, with significant Cascade snowfall through tonight into
Sunday. Will continue the Winter Storm Warning for the Cascades as a
result, except a Winter Weather Advisory in the Lane County Cascades.
We will likely see a thunderstorm or two today into early this
evening as well.
Precipitation will decrease later Sunday and Sunday night, with dry
weather expected Monday under a short wave upper ridge. Will need to
watch for some late night and morning fog Sunday night and Monday,
but do expect some sunshine and warmer temperatures Monday afternoon.
with 65 to 70 possible in the inland valleys.
The next potentially strong system approaches the coast Monday night
and moves through the forecast area Tuesday. Another round of fairly
strong wind is possible Tuesday, with possible high winds along the
coast and windy conditions inland. A shot of rain is expected with
some snow in the higher Cascades, but QPF looks less than that today.
Tolleson
.LONG TERM...Tuesday night through Saturday...After the front moves
through Tuesday, some showers will continue Tuesday night before
another front moves in for Wednesday and Wednesday evening. The
parent low centered off the B.C. coast will then send some additional
waves of moisture onshore through Thursday. That system will move
inland and weaken Thursday night before the warm front with the next
system approaches Friday followed by the associated cold front moving
through Saturday into Saturday evening. There is decent agreement in
the models through the period. All in all, the weather will be
unsettled. Snow levels during this period will yo-yo this week,
falling to near or below the passes on Tuesday and perhaps a bit
lower Thursday before climbing above the passes Friday then falling
again Saturday. Tolleson
&&
.AVIATION...00Z TAF Package...Mostly VFR across the area early this
afternoon, with areas of MVFR noted along the coast. Satellite and
radar imagery at 21Z show an enhanced precipitation band moving
onshore. Would expect increasing MVFR for the coast over the next 2-3
hours and then remaining predominantly MVFR through Sun morning.
Inland areas likely to be more VFR through this evening, but with
increasing areas of MVFR after 03Z Sun. Overall conditions improve
Sun morning, with predominant VFR by 18Z Sun.
There will be a prolonged period of strong wind, generally late this
afternoon through tonight. Coastal TAF sites likely to see frequent
gusts up to 50 kt, while gusts 35-45 kt possible at inland TAF sites.
Model soundings suggest substantial wind speed shear just off the
surface to around FL050. Some models are indicating wind speeds 55-65
kt at FL050. Thunderstorm threat over much of the forecast area
through early evening.
KPDX AND APPROACHES...VFR early this afternoon. Expect mainly VFR
through about 02Z Sun, then a mix of MVFR and VFR through at least
12Z. Predominant VFR by 18Z and continuing through Sun afternoon.
Still a slight thunderstorm threat at the terminal and vicinity
through early evening. South wind 20-25 kt with gusts 35-45 kt
through early Sun morning. Wind gradually easing Sun morning into the
afternoon. Weishaar
&&
.MARINE...Very little change from the morning update. The strong low
passed over buoy 46005 at around 5 AM with the last reported pressure
reported at 965.8 mb. The low appeared to be in a very mature state.
The center is now near 48.6N, 130.6W with automated analysis placing
the central low pressure between 972 and 975 mb. Latest model data
has it taking more of a ENE track for the next several hours. The low
is mature enough such that a second occlusion is wrapping around the
south side of the low and is nearly coming onshore across the Oregon
Coast. Storm force gusts have not appeared at our 2 reporting buoys
today, but am not inclined to drop the Storm warning yet given we are
now headed into a hybrid regime of stratiform precip with convective
elements. There is plenty of wind within reach of the convection and
cannot rule out gusts above 48 kts for the next several hours.
Seas across the waters now range 20-25 feet. They should be close to
topping out where they will remain for several more hours before
gradually easing much later tonight. Seas look to remain above 20 ft
through approximately midday Sunday before falling into the mid to
upper teens Sunday afternoon and evening.
Surface high pressure will shift over the waters late Sunday and
Monday, which will bring much quieter weather to the waters and allow
seas to subside well below 10 ft. However, the break in the weather
will be short lived as the next front will push into the region
Monday night and Tuesday with another front arriving Tuesday night or
Wednesday. Each of these quick moving storm systems appear capable of
producing Gale Force wind gusts of 35 to 40 kt and should be strong
enough to allow seas to climb back into the teens. Active weather
looks to continue into the second half of next week, but overall the
pattern looks to produce weaker storm systems more typical of April
across the waters. JBonk/Neuman
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...Winter Storm Warning until 6 PM PDT Sunday for Northern Oregon
Cascades.
High Wind Warning until 11 AM PDT Sunday for Cascade Foothills
in Lane County-Central Willamette Valley-Greater Portland
Metro Area-Lower Columbia-Northern Oregon Cascade
Foothills-South Willamette Valley.
Winter Weather Advisory until 10 AM PDT Sunday for Cascades in
Lane County.
High Surf Advisory until 1 PM PDT Sunday for Central Oregon
Coast-North Oregon Coast.
High Wind Warning until 10 AM PDT Sunday for Central Coast
Range of Western Oregon-Central Oregon Coast-Coast Range
of Northwest Oregon-North Oregon Coast.
WA...Winter Storm Warning until 6 PM PDT Sunday for South Washington
Cascades.
High Wind Warning until 11 AM PDT Sunday for Greater Vancouver
Area-I-5 Corridor in Cowlitz County-South Washington
Cascade Foothills.
High Surf Advisory until 1 PM PDT Sunday for South Washington
Coast.
High Wind Warning until 10 AM PDT Sunday for South Washington
Coast-Willapa Hills.
PZ...Storm Warning until 6 PM PDT this evening for Coastal Waters
from Cape Shoalwater WA to Florence OR out 60 NM.
Small Craft Advisory for Rough Columbia River Bar until 5 PM
PDT Sunday.
&&
Interact with us via social media:
www.facebook.com/NWSPortland
www.twitter.com/NWSPortland
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.PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PORTLAND OR
236 PM PDT SAT APR 07 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0200 PM NON-TSTM WND DMG WARRENTON 46.17N 123.92W
04/07/2018 CLATSOP OR PUBLIC
SOCIAL MEDIA REPORT OF A 40 FOOT TALL TREE SNAPPED AT THE
TRUNK 20 FEET ABOVE THE GROUND. BRIEFLY CLOSED A ROAD IN
WARRENTON FOR DEBRIS REMOVAL.
&&
SWEAGLEPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PORTLAND OR
425 PM PDT SAT APR 07 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0416 PM NON-TSTM WND DMG 4 S NESKOWIN 45.04N 123.98W
04/07/2018 LINCOLN OR DEPT OF HIGHWAYS
ODOT REPORT OF HAZARDOUS TREE OR VEGETATION AFFECTING 2
SOUTHBOUND LANES OF US 101.
0416 PM NON-TSTM WND DMG NEWPORT 44.63N 124.05W
04/07/2018 LINCOLN OR DEPT OF HIGHWAYS
ODOT REPORT OF HAZARDOUS DEBRIS ON US 20 JUST OUTSIDE OF
NEWPORT.
0345 PM NON-TSTM WND DMG DELTA PARK 45.61N 122.68W
04/07/2018 MULTNOMAH OR DEPT OF HIGHWAYS
POWER OUTAGE AFFECTING A SIGNIFICANT PART OF THE DELTA
PARK AND HAYDEN MEADOWS AREA. REPORTED BY ODOT AND LOCAL
MEDIA.
&&
SWEAGLEPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PORTLAND OR
508 PM PDT SAT APR 07 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0130 PM NON-TSTM WND DMG 1 SE PORTLAND DOWNTOWN 45.51N 122.67W
04/07/2018 MULTNOMAH OR BROADCAST MEDIA
DOUGLAS FIR TREE SNAPPED AND FELL ON A HOUSE AT SE 28TH
AND STEPHENS IN PORTLAND, DAMAGING THE HOUSE.
&&
SWEAGLEPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PORTLAND OR
551 PM PDT SAT APR 07 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0551 PM NON-TSTM WND DMG SALEM 44.92N 123.02W
04/07/2018 MARION OR BROADCAST MEDIA
MEDIA REPORT AND PICTURE OF TREE DOWN, BLOCKING HIGH ST
NEAR CROSS ST IN SALEM.
&&
SWEAGLE1 heavy snow. Local standard time, as filed.
Bear Grass and Red Hill SNOTELs reported 15 inches of snow, Mt Hood Meadows NWAC station recorded 18 inches of snow, and Timberline NWAC station recorded 17 inches of snow.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Oregon in 2018Every state in 2018This day in weather historyWarnings in Oregon, 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: 753277.