A negatively tilted upper-level shortwave in combination with a ridge of high pressure directly to east of the CWA lead to a tight pressure gradient across the Blue Mountains and strong down-sloping winds.
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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 PDT wrote it up.
A negatively tilted upper-level shortwave in combination with a ridge of high pressure directly to east of the CWA lead to a tight pressure gradient across the Blue Mountains and strong down-sloping winds.
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 Jan 7, 2:57 PM PST, 5 hours 33 minutes earlier.
Area Forecast Discussion
National Weather Service Pendleton OR
257 PM PST Sat Jan 7 2023
.MORNING UPDATE...Radar is showing some some light returns across
the forecast area this morning with unknown precipitation
reported at KYKM and KPSC earlier. Not too concerned about
freezing rain, at least not widespread, as surface temperatures
and dew points are above freezing at the aforementioned sites.
Moreover, observations have since transitioned to light rain.
Elsewhere, due to the light returns, radar is able to sample a
robust low-level jet across the Blue Mountains and their
foothills. Widespread 50-70 kt winds between 5-8 kft MSL are
evident when sampling, and low spectrum width suggests the data
are reliable. These winds appear to be translating to the surface
along exposed ridges and mountains with 50-73 mph gusts being
reported at multiple surface observations along and adjacent to
HWY-395, I-84, and OR-11. Latest guidance suggests this jet at 850
mb will increase through the day and peak this afternoon at around
45-55 kts. This raises some concerns for winds along the Southern
Blue Mountain Foothills where guidance is most aggressive with the
jet. Will continue to monitor in case a Wind Advisory is needed.
For now, have maintained the current High Wind Warning along the
base of the Northern Blue Mountain Foothills of Oregon and the
Wind Advisory for the Grande Ronde Valley. Plunkett/86
.SHORT TERM...Tonight through Monday night...Main concerns during
the short term continue to revolve around southeast winds along
the base and slopes of the Blue Mountains and through the Grande
Ronde Valley due to continued offshore troughing, tight surface
pressure gradients, and a persistent low-level jet aloft around
850 mb. KONO to KMEH and pressure difference of 8-10 mb has been
observed today, though winds through the Grande Ronde Valley and
Ladd and Pyles canyons have not responded as strongly as expected
based on the gradient. 12Z HREF paints a widespread swath of
50-100% probability of exceeding 45 mph gusts in the
aforementioned foothill and canyon areas until 1 PM PST Sunday
with probabilities peaking 3 AM to 9 AM PST Sunday morning with
the higher uncertainty further away from the base of the Blue
Mountains. Thus, have opted to add the Foothills of the Northern
Blue Mountains of Washington as well as the Foothills of the
Southern Blue Mountains to the Wind Advisory and extended in time
through 1 PM Sunday. Also extended the advisory for the Grande
Ronde Valley for the same period. Winds have largely dropped below
warning criteria for the Foothills of the Northern Blue Mountains
of Oregon so have downgraded to an advisory until the expected
stronger winds tonight; a new High Wind Warning for the Foothills
of the Northern Blue Mountains of Oregon was issued for Sunday
morning.
Otherwise, precipitation with the active pattern through the
period is expected to be light with just a couple inches of
mountain snow and some light lower-elevation rain or rain-snow mix.
Should temperatures fall below freezing in the morning in the
lower valleys, such as the Yakima and Kittitas, a slight chance of
light freezing rain would materialize. Confidence in freezing
rain is low (<25% chance).
More uncertainty in a surface low for Monday and Monday night.
Plunkett/86
.LONG TERM...Tuesday through Saturday...A progressive synoptic
pattern through next week will continue to bring periods of light
rain and mountain snow to the Pacific Northwest, with periods of
strong winds late Wednesday into Thursday along the Blue mountain
foothills and southern Grande Ronde valley. Overall, model
consensus is fairly good Wednesday and beyond, however, there is
moderate uncertainty regarding the synoptic pattern Tuesday.
Right off the bat, Tuesday starts with a fair amount of
uncertainty according to ensemble and deterministic guidance.
While the GFS members want a shortwave trough coupled with a
surface low to swing north across the PacNW, a majority of ECMWF
members weaken the shortwave trough aloft and push the surface low
to the south and east of the region. Within the clusters, this
apparent as the GFS dominated cluster favors greater precipitation
across the area as compared to the ECMWF dominated clusters. The
GFS solutions would see a continuation of snow along the crests of
the Cascades and light rain in the lower elevations through
Tuesday, whereas the ECMWF would have the northern two- thirds of
the forecast area dry with light rain and mountain snow in the
bottom third. That said, there is at least moderate confidence for
some light rain and mountain snow to occur across the forecast
area Tuesday, as generally most of the GFS members and around a
quarter of the ECMWF ensemble members do support precipitation
impacts across the region.
Wednesday and beyond, ensemble guidance is certainly in better
consensus with the progression of the synoptic pattern. Starting
Wednesday, upper level ridging will build across the western CONUS
from the southwest, with the ridge axis gradually pushing east
through the latter half of the week. Initially as the ridge
builds, the forecast area will remain dry thanks to an upper low
swinging across southern NV/UT. However, by late Wednesday through
Thursday, a surface low offshore will push a series of frontal
boundaries across the PacNW. This will result in another round of
snow in the mountains, with light rain everywhere else. There is
some uncertainty regarding precipitation amounts across the
region during this period, with the main difference in amounts
along the eastern mountains. Cluster solutions favoring a ridge
axis along the UT/NV border keep the eastern mountains drier with
likely a dusting of snow, as compared to cluster solutions
favoring a ridge axis over central/eastern UT which would likely
result in a couple inches of snowfall in the eastern mountains.
At this time, either solution is favored, though impacts will
likely be low with greater snowfall solutions. Otherwise, the
frontal system passages will tighten surface pressure gradients
along the eastern mountains, resulting in breezy downsloping winds
along the foothills of the Blues and through the southern Grande
Ronde valley late Wednesday through Thursday.
Friday, the ridge axis will push further east and be centered
along the Rockies through much of the day. GFS and ECMWF ensemble
guidance is in high agreement that another frontal boundary will
push into the PacNW, however it will dissipate as it pushes into
the Cascades, with light snow mainly along the Cascades and a
dusting possible over the northern Blues. Otherwise, the rest of
the forecast area will remain dry. As for Saturday, ensemble
guidance is in good agreement of keeping a shortwave trough
passage to our south, only resulting in another round of light
mountain snow and lower elevation light rain. Lawhorn/82
&&
.AVIATION...00Z TAFs...VFR to IFR conditions to prevail through
the period. A brief break in the parade of weather systems will
develop through this evening, then expected to return after 10Z
tomorrow morning. Light rain can be expected at sites DLS/PSC,
while a rain/snow mix will be possible at the onset of
precipitation tomorrow morning at sites RDM/BDN/YKM. Reductions in
vsby/CIGS to MVFR/IFR will also be possible with the onset of
precipitation, except at site YKM where IFR vsby is expected to
persist through this evening. Winds will be 10kts or less at
sites DLS/YKM/PSC through the period. Winds at sties
PDT/RDM/BDN/ALW will be 10-20kts with gusts up to 25kts possible
through the period. Lawhorn/82
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 41 52 34 47 / 20 40 10 60
ALW 36 51 36 47 / 20 50 10 50
PSC 31 46 32 42 / 20 50 0 70
YKM 33 40 27 37 / 30 70 10 80
HRI 34 48 33 43 / 20 40 0 60
ELN 24 38 27 36 / 50 70 10 70
RDM 41 47 31 47 / 40 30 20 80
LGD 36 41 32 40 / 10 50 10 60
GCD 37 45 31 42 / 30 50 10 80
DLS 35 45 34 42 / 60 70 30 90
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory until 1 PM PST Sunday for ORZ049-508.
Wind Advisory until 1 AM PST Sunday for ORZ507.
High Wind Warning from 1 AM to 1 PM PST Sunday for ORZ507.
WA...Wind Advisory until 1 PM PST Sunday for WAZ029.
&&
MORNING UPDATE...86
SHORT TERM...86
LONG TERM....82
AVIATION...82PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PENDLETON OR
329 PM PST SAT JAN 7 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0920 AM NON-TSTM WND GST 9 S PILOT ROCK 45.35N 118.86W
01/07/2023 M73 MPH UMATILLA OR MESONET
MESONET STATION PC321 BLUE GULCH STATION
ELEVATION: 3766 FT.
&&PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE PENDLETON OR
330 PM PST SAT JAN 7 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0940 AM NON-TSTM WND GST 7 SSE MISSION 45.59N 118.60W
01/07/2023 M60 MPH UMATILLA OR MESONET
MESONET STATION OD185 I84 WB AT CABBAGE HILL
MP223.52 STATION ELEVATION: 3283 FT.
&&PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE PENDLETON OR
357 PM PST SAT JAN 7 2023
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0512 AM NON-TSTM WND GST 7 SSE LA GRANDE 45.23N 118.01W
01/07/2023 M49 MPH UNION OR MESONET
MESONET STATION ODT18 7.4 S ISLAND CITY
(ODOT).
1145 PM NON-TSTM WND GST 4 ENE MISSION 45.68N 118.58W
01/06/2023 M50 MPH UMATILLA OR MESONET
MESONET STATION AS881 PENDLETON.
0150 AM NON-TSTM WND GST 9 S PILOT ROCK 45.35N 118.86W
01/07/2023 M53 MPH UMATILLA OR MESONET
MESONET STATION PC321 BLUE GULCH.
0520 AM NON-TSTM WND GST 5 SSE MISSION 45.60N 118.64W
01/07/2023 M47 MPH UMATILLA OR MESONET
MESONET STATION OD181 I84 WB AT MISSION
MP219.61.
0526 AM NON-TSTM WND GST 6 SSE MISSION 45.58N 118.62W
01/07/2023 M58 MPH UMATILLA OR MESONET
MESONET STATION OD184 I84 WB AT CABBAGE HILL
MP222.35.
0601 AM NON-TSTM WND GST 4 ENE MISSION 45.68N 118.58W
01/07/2023 M51 MPH UMATILLA OR MESONET
MESONET STATION AS881 PENDLETON.
0606 AM NON-TSTM WND GST 5 SSE MISSION 45.60N 118.64W
01/07/2023 M53 MPH UMATILLA OR MESONET
MESONET STATION OD181 I84 WB AT MISSION
MP219.61.
0920 AM NON-TSTM WND GST 9 S PILOT ROCK 45.35N 118.86W
01/07/2023 M73 MPH UMATILLA OR MESONET
MESONET STATION PC321 BLUE GULCH STATION
ELEVATION: 3766 FT.
0940 AM NON-TSTM WND GST 7 SSE MISSION 45.59N 118.60W
01/07/2023 M60 MPH UMATILLA OR MESONET
MESONET STATION OD185 I84 WB AT CABBAGE HILL
MP223.52 STATION ELEVATION: 3283 FT.
0946 AM NON-TSTM WND GST 6 SSE MISSION 45.58N 118.62W
01/07/2023 M65 MPH UMATILLA OR MESONET
MESONET STATION OD184 I84 WB AT CABBAGE HILL
MP222.35 STATION ELEVATION: 3025 FT.
0252 PM NON-TSTM WND GST 1 SSW LONG CREEK 44.71N 119.11W
01/07/2023 M59 MPH GRANT OR MESONET
MESONET STATION OD127 0.6 SW LONG CREEK
(ODOT) STATION ELEVATION: 3901 FT.
&&The national radar mosaic for the moment the first event began.
1 high wind. Local standard time, as filed.
The mesonet OD184 measured a gust of 63 mph at 1256 AM January 8th and the mesonet station AS881 measured a gust of 58 mph at 930 PM January 7th.
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, January 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: 1078785.