A surface low pressure coming in from the southwest led to strong downsloping winds across the base of the Blue Mountains and through the Grande Ronde Valley. These winds occurred primarily during the overnight period from February 4th through the 5th.
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The episode as NWS PDT wrote it up.
A surface low pressure coming in from the southwest led to strong downsloping winds across the base of the Blue Mountains and through the Grande Ronde Valley. These winds occurred primarily during the overnight period from February 4th through the 5th.
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 4, 2:48 PM PST, 4 hours 12 minutes earlier.
Area Forecast Discussion
National Weather Service Pendleton OR
248 PM PST Sun Feb 4 2024
.SHORT TERM...Today through Tuesday...Current radar and visible
satellite imagery showing light returns beginning to move into
Deschutes county as mid to high level clouds begin to approach the
eastern Gorge and the Lower Columbia Basin. These conditions are a
result from an upper level low pressure and associated surface
low, currently located near the San Francisco area, continuing to
move north along the California coast. These synoptic features
will near the Oregon/California border later this evening into
early Monday morning before opening up and digging back down the
California coast into Tuesday. Primary weather concerns associated
with this system include windy conditions along the base of the
northern Blue Mountains and the Grande Ronde Valley tonight
through Monday afternoon, and the potential for moderate snowfall
at higher elevations (above 4500 feet) along the east slopes of
the Cascades.
The approaching offshore low has tightened pressure gradients
between itself and a transient ridge to our east, allowing winds
to increase tonight and through Monday as it slowly broadens
across the area. The main areas of concern are along the base of
the northern Blue Mountains and across the Grande Ronde Valley
(specifically the Ladd and Pyles Canyons), where wind gusts are
already beginning to increase to between 20-25 mph at Mission and
the La Grande Airport since noon. Wind gusts are expected to peak
between 7 PM tonight through 4 PM Monday for the base of the
northern Blue Mountains, and from 7 PM tonight through 7 PM Monday
through the Grande Ronde Valley. Thus, a Wind Advisory has been
issued over the aforementioned areas during these respective
timeframes, as southerly sustained winds of 25-35 mph with gusts
of up to 50 mph will be possible. Confidence in these wind values
is high (80-90%) as a pressure gradient of 4-5.5 mb between
Meacham and Baker City is advertised by the GFS, NAM, and SREF,
with the NBM and HREF both highlighting a 70-90% chance of wind
gusts of 47 mph or higher through Monday evening.
Cloud ceilings are beginning to decrease across Central Oregon as
increasing cloud cover and light showers approach from the south.
Precipitation chances (40-70%) will continue to increase from the
south this evening, becoming widespread across our area overnight
and into Monday morning. Rain amounts will be highest over our
western zones, with areas along the east slopes of the Cascades.
Eastern Gorge, Simcoe Highlands, and the Yakima/Kittitas Valleys
picking up 0.15-0.35 of an inch through Monday afternoon. Minimal
rain amounts are expected further east and at lower elevations
with less than 0.10 of an inch expected. Snow levels will be
slowly increasing overnight from 2500-3500 feet currently to
3000-4500 feet north-to-south by noon Monday. Higher snow amounts
are also expected along the Cascades than across our eastern
mountains, with 4-8 inches likely across White and Santiam Passes
as the higher elevations of the Blue Mountains pick up only 1-2
inches. These snow amounts are below advisory criteria, but are of
note as snow rates will peak this evening across Santiam Pass and
Monday morning over White Pass. Confidence in these snow amounts
are moderate (40-60%) as the NBM highlights a 20-40% chance of 4
inches or more over both passes and the HREF showcasing a 50-70%
chance of 5 inches or more.
Precipitation chances wane and begin to congregate at elevation
along the Cascade and Blue Mountains as conditions dry elsewhere
Monday evening. This is a result from the departing system to our
south, but a weak shortwave will keep slight chances (15-25%) of
precipitation over higher terrain in the Cascades and Blue
Mountains on Tuesday. A trace of snow and less than 0.05 of an
inch of rainfall is expected over these areas as snow levels
hover between 3000-4000 feet through the day. The above normal
temperatures experienced today will slowly approach average
temperatures (mid to upper 40s) by Tuesday, as northwest flow
aloft enhances with the approaching weak shortwave early Tuesday.
75
.LONG TERM...Wednesday through Sunday...Relatively seasonable
conditions are expected through the period, with ensembles in pretty
good agreement on the synoptic pattern through next weekend. For the
first half of the period, the PacNW will be enveloped by a trough
pattern, however most of the moisture transport will fall well to
our south. The low pressure in place will still permit some light
PoPs (15-25% lower elevations, 35-45% mountains), but NBM
probabilistic QPF suggests that chances for over a tenth of an inch
of precip Wednesday through Friday are less than 30% for most of the
forecast area, nudging up to about 50-60% for the high mountains. As
a result, even though snow levels will support pass-level snow
through the period (generally 2000-2500 ft), amounts look to be
light enough to preclude any significant impacts.
Heading into next weekend, ensembles generally favor a shift toward
ridging. Discrepancies exist with regards to the magnitude of
ridging and exact timing, but consensus does favor a drier and
slightly warmer pattern. The initial transition into ridging Friday
into Saturday looks to be the best chance for area-wide PoPs, as the
flow aloft supports the most favorable moisture transport, but more
benign weather looks to prevail once we settle into next weekend
with high pressure overhead. Evans/74
&&
.AVIATION...00z TAFs...A warm front lifting through the area will
bring light rain showers to most sites starting this evening and
lasting through tomorrow afternoon. Rain may briefly mix in with
snow overnight at RDM and BDN, however no accumulations or icy
precip are expected. Elsewhere, MVFR or worse conditions due to rain
are most likely at sites along the Cascades, from central Oregon and
up through DLS and YKM, where rain is expected to be the heaviest.
Rain is more likely to be intermittent at PSC, ALW, and PDT. Winds
will remain light at less than 12 kts. Evans/74
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 53 37 49 33 / 0 40 30 20
ALW 54 38 50 35 / 10 50 40 30
PSC 53 37 46 36 / 0 50 40 20
YKM 51 35 42 33 / 0 70 70 20
HRI 51 37 48 35 / 0 50 30 20
ELN 39 33 40 32 / 10 50 70 20
RDM 46 33 48 29 / 20 70 30 10
LGD 43 37 51 34 / 0 40 40 20
GCD 43 34 49 29 / 0 50 40 20
DLS 49 37 44 37 / 0 70 70 30
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory from 7 PM this evening to 7 PM PST Monday for
ORZ049.
Wind Advisory from 7 PM this evening to 4 PM PST Monday for
ORZ507.
WA...None.
&&
SHORT TERM...75
LONG TERM....74
AVIATION...74The national radar mosaic for the moment the first event began.
1 high wind. Local standard time, as filed.
ODOT station at Cabbage Hill reported a max wind gust of 68 mph.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Oregon in 2024Every state in 2024This day in weather historyWarnings in Oregon, February 2024
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: 1164390.