A deep trough established SW flow aloft over the forecast area in early April, leading to a band of snow occurring over central Oregon and the eastern mountains of Oregon from the evening of the 3rd, falling on and off onwards and lasting through much of the day April 5.
Every event with a place to put it; 2 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 deep trough established SW flow aloft over the forecast area in early April, leading to a band of snow occurring over central Oregon and the eastern mountains of Oregon from the evening of the 3rd, falling on and off onwards and lasting through much of the day April 5.
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 Apr 3, 9:51 PM PST, 1 hour 9 minutes earlier.
Area Forecast Discussion
National Weather Service Pendleton OR
1051 PM PDT Wed Apr 3 2024
Updated Aviation Discussion
.AVIATION...06Z TAFs...Conditions will drop to MVFR to IFR over
the period and potentially locally lower as rain and snow begins
to move across the region. For Snow - currently only expecting
BDN/RDM to see snow, with BDN already reporting snow as of this
time. For Rain - precipitation overspreads all other sites here
overnight through the morning hours, and for YKM/DLS expecting
this to end during the late afternoon/early evening hours
tomorrow, but will persist through the TAF period for PDT/ALW/PSC.
This shield of precipitation will bring lowering CIGs between
1.5-2.5k feet. Between snow and rain, visibilities may drop to 3
miles or possibly lower in heavier snow bands/rain/mist. Wouldn't
be surprised to see some sites report LIFR conditions locally,
but as of this forecast not anticipating it as a widespread
feature and is not included in current TAFs. As rain/snow
departs, expect CIGs to lift back to around 5k feet. Goatley/87
&&
PREV DISCUSSION... /issued 251 PM PDT Wed Apr 3 2024/
SHORT TERM...Tonight through Friday...Satellite imagery this
afternoon shows an upper level low continuing to dive south
offshore the PacNW, while radar imagery across the area shows the
cold front is stalling across eastern OR into the ID panhandle,
with light rain having developed from Hermiston/Tri-Cities to
across the Blues. Scattered thunderstorms have also been
developing since late morning across eastern OR into western ID,
including southeastern Grant county. The most recent SPC mesoscale
analysis shows that an area of CAPE between 500-1000 J/kg is
draped across southeastern OR, while 0-6km wind shear is between
60-75kts in this area. While most of the activity will continue to
the south and east of the forecast area, the strong wind shear
could maintain a few isolated thunderstorms as they move into
parts of eastern Grant county, and southern Union and Wallowa
counties.
Later tonight, the region will continue to see a cooling trend
behind the cold front passage, with snow levels dropping to 2kft
to 3kft across the western half of the forecast area, and between
3kft to 4kft across the eastern half. The upper low offshore will
also continue it's journey south, placing the region under a
southerly flow aloft. This will allow a shortwave to travel north
across the region, producing light to moderate snow across the OR
mountains including the interior northern Blues, and across
central/north central OR. Snow accumulations of 1 to 3 inches are
expected across central OR, with around 1 inch across north
central OR. In the mountains, expect 2 to 5 inches through
tomorrow morning.
Tomorrow, the upper low will drop into northern CA, while
shortwave impulses continue to round the low and push north across
the forecast area. Light rain showers in the Columbia Basin and
lower elevation valleys/canyons will develop while light snow will
be possible across mountain locations. By tomorrow late afternoon
through Friday, the upper low will gradually travel east into the
Great Basin while continuing to guide shortwave impulses and wrap
around moisture into the forecast area. The brunt of these waves
are expected to impact the Blues, Strawberrys, and the Wallowas
through Friday night, producing heavy snow accumulations across
the mountains. Currently, NBM guidance is only indicting a 55-65%
chance of exceeding 10 inches across the Blues over the 1.5-2 day
period. That said, confidence at this time is only 40-50% in
current forecast accumulations, owing to continued changes between
model runs and forecast amounts of precipitation, therefore will
leave the Winter Storm Watch over the Blues. Otherwise, the
wrap around moisture from the upper low is expected to spill over
into the Blue Mountain foothills, with NBM guidance indicating a
45-65% chance of 0.5 inches of rainfall in these areas over a
48-hr period. High temperatures will continue to cool through the
remainder of the work week, with afternoon temps in the mid 40s to
lower 50s in the lower elevations, and 30s to lower 40s in the
mountains. Lawhorn/82
LONG TERM...Saturday through Sunday: Starting Saturday morning,
an upper-level trough moves eastward with precipitation lingering
over PacNW until Sunday morning when another trough arrives thus
bringing additional precipitation. By Monday, dry conditions begin
once the ridge moves over the forecast area. Rain/snow will be
the highlights from these back-to-back troughs with the very light
rain in the low elevations and mainly snow in mountain areas,
with snow accumulation possibly reaching to about 2 inches at the
Blue Mountains (50-75% confidence). From Saturday to Sunday
morning, there will be some gusty winds around the Columbia Basin
and Cascades with gusts varying between 25-40mph, which shows
potential for a wind advisory. Breezy conditions will occur Sunday
to Monday morning between 17-25mph across the Simcoe Highlands
and Foothills of Blue Mountains of WA.
The ensemble means and deterministic models are in good agreement
with the amplitude of the first trough moving east(>70% confidence).
However, there is a significant difference in positions of the
second trough Saturday night and the oncoming ridge Sunday night.
The models show the second trough to be over PacNW but the cluster
analysis show it to be located off Oregon coast or near California,
which can affect the timing of the precipitation (<30% confidence).
Snow levels will be at around 2000-3000ft Saturday into Sunday
morning but increases to 2500-3500ft Monday morning as the ridge
moves over the PacNW. Temperatures will warm several degrees each
day to the 50s and lower 60s by Sunday. Feaster/97
Monday through Wednesday: Models are in good agreement in having
quiet and benign weather with a warming trend for the first half
of next week. The Extreme Forecast Index shows no unusual weather
Monday through Wednesday. Cluster analysis shows agreement in the
overall pattern which has an upper low moving from northeast
Nevada to Arizona on Monday then moving east into Texas by
Wednesday. This allows an offshore ridge to build into the Pacific
Northwest which will give us mainly dry conditions. The model
clusters do have some differences as to the strength and location
of the ridge which grows each day but the differences should have
few impacts aside from temperatures.
Monday will see a west to northwest flow over the area from the
ridge. An upslope flow will bring a slight chance of rain with snow
showers above 4000 feet along the immediate Washington Cascade crest
in the late afternoon and Monday night though amounts will be barely
measurable. Temperatures will warm a couple of degrees from Sunday
to the mid 50s to lower 60s with mid 40s to lower 50s in the
mountains. Models are indicating a 60 to 90 percent chance of
temperatures above 60 in the Columbia Basin but not reaching 60
degrees elsewhere.
On Tuesday, the ridge moves closer to the coast and strengthens. A
westerly flow into the Cascades will again bring a few light showers
to the Washington Cascades and northern Blue Mountains with barely
measurable amounts. Temperatures will warm 5 to 7 degrees to the
lower to mid 60s with mainly 50s in the mountains. Models show the
Columbia Basin having a 55-85 percent chance of reaching 65 degrees.
For Wednesday. models have the ridge strengthening though how much
is uncertain. At this point, don't see showers anywhere over the
area. Temperatures warm 2 to 4 degrees more to the upper 60s to
lower 70s with mid 50s to mid 60s in the mountains. Models indicate
a 45-75 percent chance of reaching 70 in all locations below 3500
feet. Perry/83
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 34 46 34 45 / 50 70 70 60
ALW 39 50 36 47 / 60 80 90 80
PSC 41 53 41 52 / 30 70 60 60
YKM 35 52 35 53 / 10 60 30 40
HRI 36 51 37 50 / 40 70 60 60
ELN 32 51 33 51 / 10 60 40 40
RDM 29 42 26 45 / 80 70 20 20
LGD 35 48 32 44 / 90 80 80 80
GCD 33 47 30 44 / 90 60 60 60
DLS 40 53 40 53 / 20 70 20 30
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Winter Storm Watch from Thursday afternoon through Saturday
morning for ORZ502.
Winter Weather Advisory until 4 PM PDT Thursday for ORZ511.
WA...Winter Storm Watch from Thursday afternoon through Saturday
morning for WAZ030.
&&
SHORT TERM...82
LONG TERM....97
AVIATION...87The national radar mosaic for the moment the first event began.
2 heavy snow. Local standard time, as filed.
CoCoRaHS observers reported 5 inches of snow in Bend and 4.5 inches of snow in Redmond the morning of April 4.
Heavy snow accumulations of 13 inches was reported by a CoCoRaHS observer in Joesph the morning of the 5th. An Oregon Department of Transportation report observed 6 inches of snow accumulation at Enterprise, at Highway 82 near milepost 64.
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, April 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: 1174077, 1173712.