A series of cold fronts the weekend of Nov. 16th lowered snow levels across the region, which brought moderate to heavy snow accumulations across some mountain zones.
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 series of cold fronts the weekend of Nov. 16th lowered snow levels across the region, which brought moderate to heavy snow accumulations across some mountain zones.
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 Nov 15, 3:12 PM PST, 11 hours 18 minutes earlier.
Area Forecast Discussion
National Weather Service Pendleton OR
312 PM PST Fri Nov 15 2024
.Updated Aviation Discussion.
.AVIATION...06Z TAFS...VFR conditions currently at all sites, but
conditions are expected to degrade to IFR or MVFR due to reduced
visibilities and ceilings associated with the incoming system. Light
rain will be impacting all sites Saturday afternoon onward, with
visibilities dropping to between 2-4SM and ceilings of OVC015-050.
Lower visibilities will occur at KYKM/KALW/KPSC toward the end of
the period. Higher ceilings are expected to occur over Central
Oregon (KRDM/KBDN) and the foothills (KPDT/KALW), with lower
ceilings at KYKM/KDLS. Winds will stay below 10 kts for all sites
through the period. 75
&&
.PREV DISCUSSION... /issued 312 PM PST Fri Nov 15 2024/
SHORT TERM...Today through Sunday...
Bottom Line Up Front
1.Snow is on the way, to the mountains at least after a round or 2
or 3 fronts move through.
2. Breezy conditions return with the passing of the cold front.
3. Below seasonal average temperatures.
A lot is going to happen in the short term period. Winter Storm
Warnings for the WA Cascades and Blue Mountains beginning Saturday
10 AM through Monday 10 PM. A Winter Storm Watch for the OR Cascades
Sunday morning through Monday evening. Current conditions have
tapered off this afternoon leaving the region under fairly calm
conditions. Radar is devoid of any returns and the current satellite
shows clear skies along the eastern slopes of the Cascades through
the eastern Columbia Basin. Clouds are lingering over the eastern
mountains however keeping temperatures a bit on the cooler side.
Models are in relatively firm agreement with the upper level cold
front making its way across the region through the day today. Light
snow will grace the higher terrains of the Cascades and Blue
Mountains today ahead of the incoming warm front. Models show the
warm front will continue to bring the precipitation along with it
causing a brief switch to rain along the WA Cascades and the later
along the Blues. However, models show the front to move through
quickly with yet another cold front right on its heals bringing
snow right back late Saturday night. Snow levels will decrease
across the region to below 2000 ft during the first cold front,
skyrocketing back to 8000 ft during the warm front and plummeting
back to 2500 feet and below during the second round. With that said,
60-90% of the raw ensembles show Snoqualmie Pass area and portions
of the eastern slopes seeing 10-20 inches of snow with higher
amounts along the higher terrains, 60-80% for 10-13 inches along the
Northern Blues above 4000ft beginning Saturday night through Monday.
Lastly, 60-90% the OR Cascades over 4000 ft will see between 10-20
inches of snow Sunday into Monday. Please plan accordingly if
traveling along any of the passes and remember to bring your winter
kit.
Not only will we see an increase in snowfall along the mountains,
but models show the second cold front to be a bit sharper as it
makes its way across the region. Looking at the pressure gradient
tool, pressure gradients will tighten along the Cascades as the
second cold front comes across to near 9.5 mb. This will bring
breezy conditions across the region with the strongest winds occurring
through the Cascade Gaps, portions of the Columbia River Basin and
along the foothills of the Blue Mountains. 60-80% of the raw
ensembles show gusts to be above 30 mph through the aforementioned
areas beginning Saturday evening and remaining elevated through
Monday. EFI shows this type of wind set up to be above average winds
for this time of year.
Lastly, with the cold front, warm front, cold front, temperatures
will begin cool, with NBM showing temperatures in the mid to upper
40s through the Basin and foothills as well as central OR and in the
mid to upper 30s along the higher terrains. When the warm front
moves across, NBM shows the temperatures to move into the mid to
upper 50s through the Basin, Yakima, the Gorge and and foothills of
the Blues, low 50s in central OR and 40s along the higher terrains
with 70-90% of the raw ensembles in agreement. EFI is also signaling
these temperatures to still be at or below average for this time of
year even while reaching the upper 50s. Brr...Bennese/90
LONG TERM...Monday through Friday...The long term will be an active
period as the region starts under a deep upper level trough off of a
strong low in the Gulf of Alaska, which will then make its way
southwards to right offshore of the PacNW coastline as it continues
to stall and spin deep moisture into us from a westerly to
southwesterly flow through the end of the period.
Sensible weather concerns from this pattern will largely be
related to mountain snow and some breezy winds. The region will be
at the tail end of our mountain snowfall event of which winter
storm watches and warnings are already issued for. As this
activity subsides, we should see a brief lull in precipitation,
but by Tuesday evening and continuing through Wednesday the next
round of heavy QPF moves in with more mountain snow. Heaviest QPF
will be in the Washington Cascades, and with snow elevations still
between 1-3k feet through Wednesday morning, the probability of
another round of 12+ inches of snow in this area will be moderate
to high, 60-90%. Winds will also be breezy with the tightening
pressure gradient, but this time surface flow will be from the
south to southeast. This would be most conducive of stronger gusts
in Central Oregon and the Grande Ronde Valley, and in these zones
the NBM presents a 40-80% probability of gusts 45+ mph, which
would warrant an advisory if verified.
Moisture should continue to move across the region during the last
couple of days of the long term period, but confidence drops on
Thursday and Friday as model ensembles diverge notably on the
pattern. Clusters present a wide scenario of outcomes, with high
pressure either flattened and zonal flow expected for our region,
or the ridging becoming strong or broad and overtaking the region
(~15% of solutions and ~40% of solutions, respectively). Finally,
another ~40% of solutions show the ridge being amplified much more
to our east, allowing more influence from the offshore troughing.
If the later solution is correct, we should see more moisture
making its way into the region from the south which would allow
more precipitation (in the form of rain) in the lower elevations
with more mountain snow; the former solutions would bring much
more of a limitation to our low elevation QPF thanks to shadowing
effects. Overall there is moderate to high confidence (50-70%) in
the beginning of the long term, with confidence dropping low to
moderate at the end (30-50%). Goatley/87
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 25 45 36 54 / 10 10 90 100
ALW 30 47 39 51 / 20 10 100 100
PSC 30 47 42 57 / 0 10 70 80
YKM 23 42 31 53 / 0 20 80 70
HRI 29 48 40 58 / 0 10 80 70
ELN 26 42 31 49 / 0 20 90 70
RDM 19 43 34 51 / 0 20 60 70
LGD 23 41 32 41 / 40 10 100 100
GCD 22 40 31 48 / 30 10 100 90
DLS 31 46 40 54 / 0 40 90 80
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Winter Storm Warning from 10 AM Saturday to 10 PM PST Monday for
ORZ502.
Winter Storm Watch from Sunday morning through Monday evening
for ORZ509.
WA...Winter Storm Warning from 10 AM Saturday to 10 PM PST Monday for
WAZ030-522.
&&
SHORT TERM...90
LONG TERM....87
AVIATION...75The national radar mosaic for the moment the first event began.
2 heavy snow. Local standard time, as filed.
The Hog Pass SNOTEL reported an estimated 12 inches of new snow fell in a 24 hour period ending at 0800 PST on November 18th.
The High Ridge SNOTEL reported 12 inches of new snow accumulations in a 24 hour period ending at 2200 PST on November 17th. A public report from the town of Tollgate reported 20 inches of new snow in a 48 hour period ending at midnight on November 18th.
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, November 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: 1223377, 1223376.