Northwesterly flow supported by a strong polar jet in conjunction with a cold frontal boundary facilitated a sustained period of light to moderate snowfall as well as breezy to gusty winds late on February 20th through the 21st and 22nd.
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.
Northwesterly flow supported by a strong polar jet in conjunction with a cold frontal boundary facilitated a sustained period of light to moderate snowfall as well as breezy to gusty winds late on February 20th through the 21st and 22nd.
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 Feb 20, 1:57 PM PST, 3 hours 3 minutes earlier.
Area Forecast Discussion
National Weather Service Pendleton OR
157 PM PST Mon Feb 20 2023
.SHORT TERM...Today through Tuesday night...The short term will
be characterized by active weather. There are a lot of headlines out
ahead of this storm. Wind advisories are in effect for the OR Lower
Columbia Basin, WA/OR Blue Mtn Foothills, and the Simcoe Highlands
were westerly winds are gusting to 35-45 mph and will continue
through the morning hours. The advisory was extended to include the
Kittitas Valley where Ryegrass Summit has been gusting to 50-55 mph.
Winter Storm Warnings are in effect for the WA and OR Cascades as
well as the northern Blue Mountains. The warning began at 4 AM this
morning for the east slopes of the WA Cascades, for the OR Cascades,
the warning will begin at 10 PM tonight for elevations above 4500
feet. Finally, the warning for the northern Blues also begins at 10
PM and continues through 10 AM Wednesday.
Current radar is showing returns along the western portion of
Kittitas County. Cameras along I-90 were showing precipitation on
the roadways and is currently being reported as a rain/snow mix. As
the snow levels decrease through the day and into the evening, the
rain/snow mix will transition to snow. The Blue Mountains are also
seeing some returns over them and cameras are also showing
precipitation with snow in the Tollgate area and light rain over I-
84. Winds have been breezy through the morning with a few locations
seeing gusts as high as 55 mph this morning. Please drive with
caution today as the precipitation can cause slippery conditions
coupled with the high winds through much of the region.
Short term models continue to be in firm agreement with the
placement of the system. Strong northwesterly flow continues to
dominate over the region with a strong polar jet in place and aimed
directly into the region. The models also show low level winds to be
significant at each level so confidence has continued to remain high
(80%) for the wind event. The direction of the jet axis will assist
in the enhancement of the upsloping, especially along the Blue
Mountains, increasing the amount of snow totals. Currently the snow
totals are impressive with the Wa Cascades expecting anywhere from
10 to 20 inches above 3500ft. The Northern Blue Mountains will see
snow accumulations of 10 to 15 inches and the Or Cascades will see
10 to 20 inches in regions above 4000ft decreasing to 3500ft.
Temperatures today will continue to be mild with 50s in the Basin,
adjacent Valleys, Central Or, the Gorge and foothills of the Blues
and elsewhere will be in the low to mid 40s. However, an incoming
cold front through the evening and into tomorrow will bring the low
temperatures at or below freezing across the region.
Models show the cold front to move over the region beginning the
downward trend in snow levels and temperatures. Precipitation will
dominate the mountains overnight with the guidance hinting that
snowfall rates will be 1 to 2 inches per hour overnight. The high
winds over the region will cause an increase in blowing snow
bringing visibility low, so if you must travel, do so with caution.
There is also a chance (20-40%) of snow at the lower elevations
Tuesday and overnight, although guidance shows that these amounts
will be only 1 to 2 inches with medium confidence (25-50%) of
occurrence. Temperatures tomorrow will be in the low 50s in the
Basin, 40s elsewhere with the higher terrains in the mid 20s to low
30s. Bennese/90
.LONG TERM...Wednesday through Monday...A deep upper level trough
will be over the region Wednesday ushering in some cold Canadian air
into the Pacific Northwest under a northerly flow. Will be some
lingering snow showers across the region including the Columbia
Basin but only expect minor accumulations. A shortwave dropping out
of Canada will begin to form a secondary upper level low along the
Pacific Northwest coast Wednesday night into Thursday. This will aid
in some continued light snow accumulations mainly across central and
NE Oregon with temperatures running around 20 degrees below normal
across the entire forecast area. The low will drop down the coast
towards California late Thursday and into Friday ending the snow
showers but the cold conditions will remain. Ensemble models show
fair agreement that a transitory ridge over the eastern Pacific will
pass over the PacNW Friday into Saturday followed by an increasing
westerly flow over the weekend. There are some timing issues
regarding shortwave features which increase forecast uncertainty but
the overall trend is to begin increasing precipitation across the
forecast area late Saturday through Monday. This will coincide with
a gradual warming trend but there are concerns for some wintery mix
precipitation Sunday morning mainly along the east slopes of
the Washington Cascades and portions of the Lower Columbia Basin.
&&
.AVIATION...00Z TAFs...VFR conditions to prevail through the period.
CIGS will mostly be bkn-ovc AOA 5kft to 10kft AGL overnight then
some clearing late overnight and early Tuesday. Winds will be the
biggest concern increasing overnight to 20-35kts and gusts 35-55kts
before beginning to decrease early Tuesday but still remaining windy
through the day.
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 35 45 23 33 / 40 60 50 40
ALW 36 47 27 36 / 60 80 60 50
PSC 40 51 26 35 / 30 50 40 30
YKM 34 49 21 31 / 40 30 60 20
HRI 38 49 25 34 / 30 40 40 40
ELN 33 44 22 29 / 50 40 70 20
RDM 30 41 23 34 / 20 60 40 20
LGD 33 40 25 32 / 80 80 70 40
GCD 31 41 23 34 / 50 80 60 30
DLS 39 47 30 37 / 60 70 40 50
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory from 6 PM this evening to 10 AM PST Tuesday for
ORZ041.
High Wind Warning from 6 PM this evening to 10 AM PST Tuesday
for ORZ044-507-508-510.
Winter Storm Warning from 10 PM this evening to 10 AM PST
Wednesday for ORZ502-509.
Wind Advisory from 10 PM this evening to 10 AM PST Tuesday for
ORZ505-511.
WA...Wind Advisory from 6 PM this evening to 10 AM PST Tuesday for
WAZ024-027.
High Wind Warning from 6 PM this evening to 10 AM PST Tuesday
for WAZ026-028-029-521.
Winter Storm Warning from 10 PM this evening to 10 AM PST
Wednesday for WAZ030.
Winter Storm Warning until 4 AM PST Wednesday for WAZ520.
&&
SHORT TERM...90
LONG TERM....91
AVIATION...91PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PENDLETON OR
245 PM PST MON FEB 20 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0200 PM NON-TSTM WND GST 2 ESE KENNEWICK 46.18N 119.13W
02/20/2023 M50 MPH BENTON WA TRAINED SPOTTER
SPOTTER REPORTED WINDS 12 TO 20 MPH WITH A
GUST TO 50 MPH.
&&
RQBThe national radar mosaic for the moment the first event began.
1 high wind, 1 strong wind, 1 heavy snow. Local standard time, as filed.
The mesonet station XMRY 5 miles west southwest of Rufus, OR measured a peak gust of 58mph at 2038 PST on February 20th.
The ASOS at the Hermiston Municipal Airport, OR measured a wind gust of 61 mph at 0201 PST on February 21st. A trained spotter in Irrigon, OR measured a wind gust of 50mph at 2230 PST that also produced damage to roof shingles.
The SNOTEL site Clear Lake measured 8 inches over a 20 hour period ending at 0000 on Feb 22nd. The SNOTEL site Hogg Pass measured 8 inches over a 24 hour period ending at 0200 on Feb 22nd.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Oregon in 2023Every state in 2023This day in weather historyWarnings in Oregon, February 2023
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: 1083793, 1083795, 1083584.