A Pacific system brought a mix of snow, sleet and freezing rain to south-central and southeast Washington.
Every event with a place to put it; 3 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 PDT wrote it up.
A Pacific system brought a mix of snow, sleet and freezing rain to south-central and southeast Washington.
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 Pendleton, OR wrote its last area forecast discussion before the first event at Dec 28, 9:41 AM PST, 3 hours 59 minutes earlier.
Area Forecast Discussion...Updated
National Weather Service Pendleton OR
941 AM PST Thu Dec 28 2017
Updated aviation discussion
.SHORT TERM...Today through Friday...Area of interest will be
mainly Washington where moisture flow is more focused and air mass
will remain subfreezing for the longest period. Impacts will be
greatest here due to the duration and potential depth of
precipitation mix. Winter weather advisories for a mixture of
freezing rain and snow will remain in effect for the counties in
Oregon bordering the Columbia River extending north into
Washington. The Oregon counties should be out of the cold air
during the evening and the advisory should be able to be lifted.
Models continue to try to warm atmosphere too quickly and will
keep the advisories going in Washington through tonight and into
Friday. If if looks like heavier precipitation is going to hit
these Washington areas, the winter weather advisory will need to
be upgraded to a warning. Will monitor closely for this.
&&
.AVIATION...18Z TAFS. KBDN and KRDM will see VFR conditions through
the forecast period. Snow or mixed precipitation will spread across
the area this afternoon and continue through the night. A transition
from snow to freezing rain to rain will occur at KPDT...KDLS...and
KALW this evening. Snow will begin to mix with and change to
freezing rain or rain at KPSC and KYKM later tonight. MVFR
conditions will prevail...except KYKM, KPSC, and KALW will see
IFR/LIFR at times. Winds will generally be 10 kts or less through
the period...except KRDM and KBDN 10-15 kts tonight. Earle
&&
.PREV DISCUSSION... /issued 339 AM PST Thu Dec 28 2017/
LONG TERM...Friday night through Wednesday...An upper level
shortwave will drive a cold front across the region Friday night.
What's left of the shallow cold air mass in the Columbia Basin
should be gone by then. Decreasing showers across the lower
elevations are expected but with a continuation of rain/snow in the
mountains. A few mostly snow showers will continue in the favored
upslope areas on Saturday but an overall drying trend will take
place by Saturday night. A transitory ridge will build over the
region on Sunday into Monday with fair and cold weather. There could
be a little patchy valley fog. Highs will be in the 30s with some
20s mountains. On Tuesday have kept the forecast dry for now per the
ECMWF model. However the GFS is hinting at a weak system with a warm
layer aloft that could result in some light freezing precipitation.
Wednesday looks to be dry again with cold high temperatures mostly
in the 30s. 78
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 36 35 49 36 / 70 70 80 80
ALW 37 35 48 37 / 70 70 90 90
PSC 33 30 42 34 / 60 60 80 70
YKM 33 29 41 30 / 60 60 80 40
HRI 34 32 46 35 / 60 70 80 70
ELN 32 28 38 29 / 70 60 90 40
RDM 46 37 49 32 / 20 40 40 40
LGD 39 35 44 33 / 60 90 90 90
GCD 44 36 48 33 / 40 70 60 50
DLS 40 35 50 37 / 80 80 80 60
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Winter Weather Advisory until 10 PM PST this evening for ORZ041-
044.
Winter Weather Advisory until 7 PM PST this evening for ORZ507-
508-510.
WA...Winter Weather Advisory until 10 PM PST this evening for WAZ024-
521.
Winter Weather Advisory until noon PST Friday for WAZ026>028.
Winter Weather Advisory until 7 PM PST this evening for WAZ029.
Winter Weather Advisory until 10 AM PST Saturday for WAZ520.
&&
79/78/81The national radar mosaic for the moment the first event began.
3 ice storm, 1 heavy snow. Local standard time, as filed.
Estimated 6 to 8 inches of snow with a cover of ice at Cle Elum in Kittitas county. Snow and ice occurred in a period of under 10 hours. Temperatures warmed above freezing 3 to 4 hours after report.
One quarter (0.25) inch of ice from freezing rain 5 miles southwest of Richland in Benton county. Quarter inch amounts of ice reported in and around the Tri-Cities area with vehicles off the road.
One quarter (0.25) inch of ice from freezing rain 5 miles west of Ellensburg in Kittitas county.
One quarter (0.25) inch of ice from freezing rain at Tieton in Yakima county.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Washington in 2017Every state in 2017This day in weather historyWarnings in Washington, December 2017
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: 729816, 729819, 729817, 729818.