An upper level trough and surface cold front passage enhanced by an atmospheric river produced bands of moderate to heavy snowfall across portions of our mountain zones within the atmospheric river path through the weekend.
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.
An upper level trough and surface cold front passage enhanced by an atmospheric river produced bands of moderate to heavy snowfall across portions of our mountain zones within the atmospheric river path through the weekend.
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 Mar 15, 3:13 AM PST, 47 minutes earlier.
Area Forecast Discussion
National Weather Service Pendleton OR
413 AM PDT Sat Mar 15 2025
Updated Aviation Discussion
.SHORT TERM...
Today through Tuesday...A trough and strong short wave will move
across the region today and bring a round of precipitation, mainly
over the mountains, though some light precipitation is expected
over the lower elevations.
This system will move out tonight which will allow for a second
and more robust area of moisture to arrive tonight and continue
into Sunday, especially for the Oregon Cascades, associated with
an atmospheric river. The moisture will slowly move southward
into Monday morning.
Drier weather is expected on Monday morning most everywhere,
except for some lingering precipitation over the mountains. Monday
afternoon there could be some renewed precipitation chances,
except for the Columbia Basin, Yakima and Kittitas Valleys as the
axis of the trough passes over the Pacific Northwest, but still
the best chances are confined to the mountains. A ridge will start
to build in Monday night and most areas will see dry weather
outside of lingering precipitation in the higher terrain.
QPF today will generally be upwards of an inch along the crest of
the Cascades and about 0.50 to 0.75 inches and locally higher
amounts in the Blue Mountains. The lower elevations will see
significantly less, generally only a few hundredths.
Snow accumulations during the day today will be 6 inches plus in
the Oregon Cascades probably around 5 inches along the crest of
the Washington Cascades and probably 2 to 4 in the Blues (outside
of the highest terrain).
Beginning this evening/tonight and continuing into Sunday night
(the second event) QPF amounts will be 2 inches or more in the
Oregon Cascades, upwards of an inch in the Washington Cascades.
Around an inch along the crest of the Blue Mountains and generally
0.10 to 0.25 inches in the lower elevations. However, portions of
central Oregon could even see around an inch.
Snow totals will be 1 to 3 feet along the Oregon Cascade crest,
with 3 to 6 inches below 3000 feet. Confidence is very high (70
to 90 percent) in these numbers. Snow totals of 10 to 18 inches
for the Washington Cascades above 2000 feet. Confidence is high
(60 to 80 percent) in these numbers. Snow totals of 10 to 20
inches for the Blue Mountains above 4000 feet. Confidence is
moderate to high (50 to 70 percent) in these numbers, mainly due
to rising snow levels. Winter Storm Warnings remain in effect for
the Cascades and a Winter Weather Advisory is in effect for the
Blues.
Snow levels which will start out between 2000 and 3000 feet
everywhere on Saturday will remain between 2000 and 3000 feet in
the Washington Cascades Sunday morning. However, they will rise
everywhere else to between 4000 and 5000 feet, before decreasing
again, but will remain between 3500 and 4500 feet over the Oregon
Cascades and Blue Mountains.
The ECMWF EFI has a 0.7 to 0.8 anomaly for QPF and snow along the
Oregon Cascades today. However, on Sunday the anomaly is 0.95 to
0.99, with some embedded areas of 1.00 and shift of tails of 5!
It will also be breezy to windy today with widespread wind gusts
in the 20 to 30 mph range especially in the morning to early
afternoon, with highest wind gusts in the foothills of the Blue
Mountains, where winds could gust as high as 50 mph. Wind
advisories remain in effect in these areas. The NBM probabilities
of wind gusts >=39 mph are 70 to 100 percent in these areas, plus
nearby locations such as the Columbia Basin, Kittitas Valley,
Yakima Valley, Cascade Gaps and Simcoe Highlands. The NBM
probabilities of wind gusts >=47 mph are 50 to 70 percent across
the foothills of the Blue Mountains, portions of Simcoe Highlands
and portions of the Columbia Basin.
Sunday will be breezy, but less so than today. Wind gusts will
generally be in the 25 to 35 mph range in the normally breezy
areas. Probabilities of NBM wind gust of >=39 mph are 50 to 70
percent in these areas. Probabilities of wind gusts >=47 mph are
50 to 60 percent over a much smaller area.
.LONG TERM...
Tuesday through Saturday...Models are in good agreement on the
progression of the 500 mb pattern through the extended period.
Overall the weather will be largely unsettled with periods of rain
and mountain snow and temperatures close to normal for this time
of year. On Tuesday through early Wednesday there will be
transitory ridging over the region and mostly dry conditions.
Wednesday night and Thursday a relatively deep upper level trough
will move across the region bringing rain and mountain snow. On
Thursday afternoon marginal instability is forecast to develop
especially over the eastern mountains with 200-300 J/kg of MUCAPE.
Forecast soundings show steep low to mid level lapse rates and
deep enough CAPE for that could support a few LTG strikes. However
NBM thunder probs are 7-9% over the eastern mountains for
Thursday and given the long lead time have opted to keep TSTMS out
of the forecast for now.
Another upper trough will impact the region Friday and Saturday
bringing more lower elevation rain and mountain snow. Friday night
and Saturday could be windy mainly along the ridges with
probabilities of 45 mph gusts of 30-60%. The GFS is also forecasting
a 45 kt 850 jet. Mixing these winds down to the lower elevations is
a bit more In question given a warm advection wind profile and near
surface stable layer.
50th percentile QPF for Wednesday night through Saturday ranges from
.10-.30 for the lower elevations, .50-1.0 for the northeast
mountains and 1-2 inches for the Cascade east slopes. This could
lead to at least borderline winter highlight potential (40-50%
chance) for the east slopes given the amount of QPF forecast. 78
&&
.AVIATION...
12Z TAFS...VFR conditions will prevail for much of the day. BKN
clouds at 035-060 may thin out for a while this morning and
afternoon as scattered showers taper off. There will still be BKN
mid and high clouds. Winds will ramp up considerably this morning to
15G30kt with some potential for brief gusts to 35 kt. Winds at KDLS
will be lighter at 10-15 kt. The next wave of precipitation will
move into the region from SW-NE this evening. This will lower
ceilings to 025-040 with localized MVFR VSBYS. 78
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 54 42 53 33 / 60 60 90 50
ALW 52 42 52 35 / 70 70 90 60
PSC 57 41 55 33 / 30 50 70 20
YKM 53 35 52 28 / 80 70 60 10
HRI 57 41 55 32 / 30 60 80 30
ELN 49 33 49 28 / 50 70 70 20
RDM 49 35 48 25 / 60 90 100 50
LGD 46 36 48 29 / 80 80 100 70
GCD 46 36 50 28 / 80 90 100 80
DLS 52 39 51 35 / 80 80 80 30
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Winter Weather Advisory until 11 PM PDT Sunday for ORZ502.
Wind Advisory from 8 AM this morning to 5 PM PDT this afternoon
for ORZ507.
Wind Advisory until 5 PM PDT this afternoon for ORZ508.
Winter Storm Warning until 11 PM PDT Sunday for ORZ509.
WA...Winter Weather Advisory until 11 PM PDT Sunday for WAZ030.
Wind Advisory from 8 AM this morning to 5 PM PDT this afternoon
for WAZ029.
Winter Storm Warning until 11 AM PDT Sunday for WAZ522.
&&
SHORT TERM...77
LONG TERM....78
AVIATION...80The national radar mosaic for the moment the first event began.
2 heavy snow. Local standard time, as filed.
The Bumping Ridge SNOTEL measured 13 inches of new snow in a 24 hour period ending at 1900 PDT on March 15th. The White Pass SNOTEL measured 12 inches of new snow in a 31 hour period ending at 0000 PDT on March 16th.
The Touchet SNOTEL measured 10 inches of new snow in a 12 hour period ending at 1600 PDT on March 15th.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Washington in 2025Every state in 2025This day in weather historyWarnings in Washington, March 2025
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: 1249217, 1249219.