or discuss
Office: MFR
FXUS66 KMFR 091035
AFDMFR
Area Forecast Discussion
National Weather Service Medford OR
235 AM PST Tue Dec 9 2025
.DISCUSSION...Satellite and observations show that low clouds are
developing across some west side valleys, including the Rogue
Valley. Heavier cloud cover is preventing fog development in more
east side spots, including Klamath Falls for now. Radar has a few
showers passing in far northern Coos and Douglas counties as they
move east tonight. Through the morning, these showers are forecast
to reach ~0.25"- 0.50" near the Douglas/Lane County border. Snow
levels in the affected areas are above 8,000 feet tonight.
The upper level high to our southwest off of central California is
still looking to be enough to keep most of the activity north near
Portland and Seattle this week. The main areas to see rainfall for
the next few days will be the same locations to see it now. Between
this morning and Wednesday morning, very northern Coos and Douglas
counties, including parts of the Cascades, can expect 0.30"-0.75",
with near 1.25"-1.75" near the northernmost part of Douglas
County. Most of the rain will fall between this morning and into
the evening. Although most of this will be occurring in a 12 hour
period, there is a lower concern for flooding with this compared
to areas north of us. East side and Northern California have the
lowest chances for rain with less than .15" from Chemult to Fort
Rock being the most to expect.
Although the area will be dry, east side will have to deal with
stronger winds between now and this afternoon. A mid-level jet of 50-
60 kt with similar speeds at 300 mb show that strong winds are
forecast to reach the surface during this time with gusts near 50
mph. A Wind Advisory is in effect through this evening, and this
includes areas near Silver Lake, Summer Lake, and Paisley. Wind
gusts near 45 mph have already been reported at Summer Lake
early this morning. Please see the NPWMFR for more information.
Getting into the middle of the week, the high pressure to our
southwest takes control and brings drier conditions through at least
the start of next weekend. Earlier models were showing a continued
chance of showers at the coast through the work week, but this has
started to back off. The EC has also backed off on weekend rain
chances, but it is still coming in earlier than the GFS with a
Monday morning vs Monday afternoon timeframe. Either way, there is
some more agreement that early next week could have active weather
in both Southern Oregon and Northern California. In the meantime, we
will be watching for how the system the next few days moves through
and watch for how the models handle the next week after. -9
&&
.AVIATION...09/06Z TAFs...A front remains aimed at the Oregon Coast
just north of North Bend. This is bringing gusty winds to the coast
and a variety of ceiling conditions across the region. Along the
coast and just offshore, IFR and LIFR ceilings are expected to
prevail through the TAF period, with visibility also lowering
Tuesday morning as the front slowly sags south. VFR conditions
generally prevail across the region, but LIFR conditions are
developing in the Rogue/Illinois/Applegate Valleys, and these lower
conditions will prevail into Tuesday morning. In the Umpqua Basin,
the proximity of the front could limit fog development there, but
MVFR conditions are still expected tonight into Tuesday morning.
Meanwhile, strong winds aloft will persist near the Cascades and
over the east side in Oregon (north of Highway 140) tonight into
Tuesday where higher terrain could experience gusts in excess of 50
mph. This could lead to some low-level wind shear over there (NE of
Klamath Falls) since a low-level inversion probably doesn't allow
these winds to mix all the way to the surface in some valleys. Even
so, vertical mixing may improve Tuesday to allow surface wind gusts
to 50 mph from around Summer Lake eastward.
&&
.MARINE...Updated 200 AM PST Tuesday, December 9, 2025...Gusty south
winds and steep wind waves combined with westerly swell will
maintain conditions hazardous to small craft through at least today.
Winds subside tonight, but west swell persists into Wednesday,
especially north of Cape Blanco. Conditions improve for the latter
half of the week as swell dominated seas gradually lower. Expecting
showers over the waters through mid-week as well which could further
reduce visibilities (fog/low clouds expected as well) over the next
couple days.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory until 10 PM PST this evening for ORZ030-031.
CA...None.
PACIFIC COASTAL WATERS...Small Craft Advisory until 1 AM PST
Wednesday for PZZ356-376.
Small Craft Advisory until 10 AM PST Wednesday for PZZ350-370.
&&
$$
Office: PQR
FXUS66 KPQR 090604 PAA
AFDPQR
AAA
Area Forecast Discussion...UPDATED
National Weather Service Portland OR
1004 PM PST Mon Dec 8 2025
Updated aviation discussion.
.SYNOPSIS...A strong atmospheric river is underway across the
Pacific Northwest, bringing heavy rainfall, breezy winds, and
widespread hydrologic concerns. Widespread river flooding is
likely across the region, along with urban and small stream
flooding due to persistent heavy rain. Wind may lead to downed
trees and power outages due to saturated soils.
&&
.SHORT TERM...Now through Wednesday...The strong atmospheric
river (AR) event has begun across the Pacific Northwest, with
radar imagery showing moderate to locally heavy rain across
northwest Oregon and southwest Washington as of early Monday
afternoon. Satellite imagery clearly shows a long, narrow band
of moisture extending from the Pacific Northwest out 3000+ miles
offshore, and about 1200 miles northwest of Hawaii. This
atmospheric river is being driven by a sub-tropical ridge
centered just offshore of Southern California and Baja
California (~32.05N/130.94W), and a trough centered south of the
Aleutian Islands of Alaska (~45.79N/164.89W). Moisture is being
advected along the northwestern periphery of the ridge and the
southeastern periphery of the trough, leading to the extended
band of moisture progressing toward the Pacific Northwest.
Ensemble guidance suggests minimal change in the synoptic
pattern over the next 48 hours; therefore, this atmospheric
river event and associated impacts are expected to last through
at least Wednesday.
There are one of two surges of moisture coming into the Pacific
Northwest with this AR. The first is coming in right now, which
is associated with integrated vapor transport (IVT) values of
750-900 kg/ms based off GFS and Euro ensemble guidance. This
will maintain steady rainfall and lead to substantial rainfall
amounts across western Washington and far northwest Oregon
(especially Salem northward). Lower rainfall amounts are
forecast for the southern Willamette Valley (Eugene) as most of
the moisture is being directed further north. Urban and small
stream flooding is possible throughout this AR event, especially
in areas that are low-lying and have poor-drainage. If you will
be commuting during periods of heavy rain, make sure to slow
down, use your headlights, and leave plenty of distance ahead of
you.
Since 12 AM Monday, weather stations have already reported
1.5-2.25 inches of rain across the north Oregon and south
Washington coasts, Willapa Hills, north Oregon Coast Range, and
south Washington Cascades and foothills. These amounts were
achieved by heavier rainfall rates of 0.25-0.50" per hour. Based
off the latest REFS guidance, most ensemble members suggest
that these rainfall rates will continue through late Monday
evening into early Tuesday morning over the aforementioned
areas. Rainfall rates this high will result in rivers and creeks
that drain off the Willapa Hills and Clatsop/Tillamook Counties
to start rising sharply through the evening (see hydrology
section for more details on river flooding). Elsewhere, rainfall
amounts since midnight generally range from 0.25-1", with the
highest amounts further north you go. South of Albany, OR and
across the Lane County Cascades, amounts have been around 0.10"
or less, which is expected given the more northward track of the
AR.
This plume of AR moisture will briefly track southward tonight
into early Tuesday morning, bringing increased rainfall toward
Lane County. Will see a very brief break in rainfall rates
across far northwest Oregon and southwest Washington Tuesday
morning, but that doesn't mean we'll be clear of any impacts.
Local rivers tend to lag a few hours following heavy rainfall,
so will most likely see rivers continuing to rise and
potentially hit flood stage even when rain has decreased.
Again, more details in the hydrology section on this.
The second surge of AR moisture will hit western Washington and
far northwest Oregon Tuesday afternoon into Wednesday, bringing
another round of moderate to locally heavy rainfall to these
areas. It will be a similar set-up as today, but this time
ensemble guidance suggests IVT values will be around 600-700
kg/ms. Given the amount of rain that will have fallen before
this second round, local rivers will continue to rise and
concerns for urban and small stream flooding will continue. For
snow and winter sport lovers, unfortunately this AR will be very
warm and snow levels will remain above 8000 feet through
Wednesday.
Wind will also potentially bring impacts during this AR event.
Wind Advisories remain in effect through 4 AM Tuesday across the
central/north Oregon Coast Range, Willapa Hills, Willamette
Valley from Salem northward, and southwest Washington lowlands.
Southerly winds are forecast to gust up to 30-40 mph tonight.
Saturated soils will increase the likelihood that even moderate
gusts could cause uprooting of trees and lead to damage. While
there is moderate to high confidence in potential impacts due to
wind, there is low confidence on exactly where impacts may
occur. If you see a downed power line, move away from it. Do not
drive over downed power lines. If you come into contact with a
downed power line, stay inside the car and call for help. -10
.LONG TERM...Wednesday Night through Sunday...The atmospheric
river event weakens Wednesday afternoon into Thursday as
moisture transport gradually decreases. Light residual showers
continue, with some localized areas of moderate rain showers
over higher terrain across southwest Washington and the north
Oregon Coast Range. By Thursday, the pattern transitions toward
a more typical post- frontal regime with shower activity
gradually decreasing and winds weakening. Friday becomes drier
as high pressure builds over the region. Snow levels will also
gradually lower heading into the weekend, but still remain above
pass-level at around 5500-6500 feet. Despite the weather
becoming more tame late in the week, rivers and soils will
continue responding to the cumulative rainfall load from the
current atmospheric river event. Any slow-responding rivers
within flood stage will need extra time to subside. -10/12
&&
.AVIATION...The strongest portion of the first stage of the
atmospheric river continues to shift southward today with the
frontal edge hitting the south Washington coast. This system has
been exhibiting wind speeds around 30 kt at the surface with some
exposed areas within the Columbia River Gorge above 3000 ft MSL seeing
gusts up to 65 kt. The winds are beginning to ease inland though
are continuing to blow along the coast. Widespread gusts up to 30
kt expected along coastal terminals. Winds inland remain gusty
with speeds around 20-25 kt. We are beginning to see the shift in
flight conditions as the system shifts southward. Northern runways
are beginning to see CIGs lift to VFR while coastal and central
runways are remaining IFR or MVFR. Through the night the front
will bring the southern portions of the forecast area the MVFR
conditions.
Through the day on Tuesday after 18Z, the atmospheric river will
move north once again. Think of this system doing the "wave". As
it does so, the areas that saw a brief reprieve will once again
deteriorate. Overall, while a dynamic system with many different
moving parts, the impacts will be similar through the next
24-hours.
Will add, that while it does not impact most of our terminals or
runways, wind speeds at around 5000 ft MSL are gusting as high as
80 kt then decrease to around 70 kt after 21Z Tue. This is a very
active jet stream.
KPDX AND APPROACHES...A mixture of VFR and MVFR conditions over
the next 24 hours. Timing has been incredibly difficult due to the
movement of the atmospheric river. Portland has been sitting in
the bullseye of the system and therefore winds and rain have been
strong. These conditions will continue to improve over the next
few hours, but will deteriorate once again after 18Z Tue as the
frontal system moves right back over. While winds will decrease
through the day, winds aloft remain quite strong. -27
&&
.MARINE...Gales continue across all zones as a strong system
passes over the region. Wind gusts 35-45 kt will continue through
late tonight - strongest over the inner waters. The gale warning
remains in effect until 1 AM Tuesday.
A lull is expected early Tuesday morning as the frontal boundary
drops southward, decreasing winds from north to south. Wind gusts
are expected to drop below 20 kt everywhere except zones PZZ273
and PZZ253. Seas will also remain steep during this time so a
Small Craft Advisory will follow the gale warning from 1 AM to 7
PM Tuesday to cover these elevated conditions. Another front is
expected to pass through the waters late Tuesday into Wednesday
and will push wind gusts closer to 30-35 kt. There is increasing
potential for gales Tuesday evening into the overnight and may
require an upgrade to another Gale Warning. Seas will increase
into the low to mid teens with this second system, reaming above
10 feet through Wednesday night. -19
&&
.BEACH HAZARDS...Tidal overflow flooding around high tide is
possible on Tuesday, December 9. Despite total tide forecasts
decreasing over the coming days, river levels will be rapidly
rising due to a prolonged period of heavy rain through
Wednesday. Confidence has increased that several rivers along
the Oregon Coast north of Lincoln City and the SW Washington
Coast will reach at least 80% of flood flow by high tide Monday
afternoon, when total tide forecasts are expected to peak near
or slightly above 9.5 ft. Therefore, a Coastal Flood Advisory
for tidal overflow remains in effect until 6 PM PST today for
these coastal zones. It appears the threat for tidal overflow
flooding is low on Tuesday, as total tide forecasts decrease
considerably and are well below the 9.5 foot threshold. That
said, minor tidal overflow flooding cannot be completely ruled
out for a brief period of time around high tide on Tuesday given
river levels will be running quite high at that time. Will
continue to monitor the tidal and river forecasts for Tuesday.
Additionally, there is an elevated threat for sneaker waves late
Wednesday through Thursday along the SW Washington coast south
through the central Oregon coast. The swell period increases to
around 14-15 seconds with swell heights around 9-11 ft, with
swell heights and swell periods decreasing late Thursday night.
This will create energetic waves that will present a moderate to
high risk for sneaker waves, waves which can run significantly
farther up a beach than normal, including over rocks and jetties.
Sneaker waves can suddenly knock beachgoers off if their feet and
quickly pull them into the frigid ocean which may lead to serious
injury or drowning. Caution should be used when in or near the
water. Always keep an eye on the waves, and be especially watchful
of children. -23/03
&&
.HYDROLOGY...A series of frontal systems will maintain very wet
conditions through much of this week. The most notable period
will extend through late Wednesday, when a long-duration
atmospheric river will bring significant rainfall and the
potential for widespread river flooding across southwestern
Washington and northwestern Oregon. There is a 10% chance for
72-hour rainfall of up to 6-8.5 inches in the Cowlitz Valley,
lower Columbia, Portland/Vancouver metro and northern Willamette
Valley, 4-6 inches in the central Willamette Valley, 3-4 inches
in the southern Willamette Valley, 7-11 inches in the Cascades,
Cascade foothills, Coast Range, and the coast, except 3.5-7
inches from Florence to Newport and in areas of higher terrain
in Lane County. While rain amounts this high are unlikely to
occur, they represent a reasonable worst case scenario. This
outcome would result in widespread major flooding. Chances for
high total rainfall amounts as well as brief periods of locally
heavy rainfall in Lane County have continued to trend downward
today. This suggests future river model suites will see similar
downward trends in the likelihood of river flooding.
Although rain will likely become lighter on Thursday, the
threat of flooding will linger along slow-responding rivers.
Rivers draining the Coast Range and Willapa Hills have a 40-70%
chance of reaching moderate flood stage and a 20-50% chance of
reaching major flood stage, with a handful of rivers already
observing flooding, namely the Grays River draining the Willapa
Hills in Major flood and the Wilson River in Tillamook in Minor
flood. Additionally, many Willamette River tributaries that
drain from the Coast Range and Cascades have anywhere from a
40-60% chance of reaching minor flood stage and a 20-40% chance
of reaching moderate flood stage. Flooding of the Willamette
mainstem rivers have a very low chance to occur (5-15%).
Probabilities for specific river points can be found at the
National Water Prediction Service website. Flood Warnings have
been issued for the Naselle River near Naselle and the Grays
River near Rosburg draining the Willapa Hills in southwestern
Washington, the Wilson and Trask Rivers near Tillamook, and
Johnson Creek at Sycamore near Milwaukie and along the southern
edge of the City of Portland.
There is also increasing confidence in the potential for
flooding along small creeks and streams as well as urban
flooding, including roadway flooding. Latest high-resolution
guidance favors a band of heavier precipitation lingering over
southwestern Washington and far northwestern Oregon late this
evening, before sagging southward through the early morning
hours. These potential heavy rainfall rates could make for a
hazardous morning commute along the I-5 corridor from Salem
north through Portland/Vancouver to Kelso/Longview with abundant
water atop area roadways. Periods of heavy rain will also
increase the risk for landslides in areas of steep terrain and
debris flows over recently burned areas. People, structures, and
roads located below steep slopes, in canyons, and near the
mouths of canyons may be at serious risk from rapidly moving
FXUS66 KPQR 090604 PZB
AFDPQR
landslides. Therefore, a Flood Watch remains in effect across
all of southwest Washington and northwest Oregon from now until
4 AM Friday.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...Coastal Flood Advisory from noon to 5 PM PST Tuesday for
ORZ102.
Wind Advisory until 4 AM PST Tuesday for ORZ104>115-123.
WA...Wind Advisory until 4 AM PST Tuesday for WAZ202>208.
PZ...Gale Warning until 1 AM PST Tuesday for PZZ210-251-271.
Small Craft Advisory from 1 AM to 7 PM PST Tuesday for PZZ210-
251-271.
Gale Warning until 7 AM PST Tuesday for PZZ252-253-272-273.
Small Craft Advisory from 7 AM to 7 PM PST Tuesday for PZZ252-
253-272-273.
&&
$$
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Office: PDT
FXUS66 KPDT 090659
AFDPDT
Area Forecast Discussion
National Weather Service Pendleton OR
1059 PM PST Mon Dec 8 2025
.AVIATION...06Z TAFs...Predominantly VFR conditions are forecast
into the overnight hours for all sites as a strong rain shadow is
keeping rain pinned to the mountains. Early Tuesday morning
through Tuesday evening, rain is forecast for most sites as a band
of rain sets up over the region. Some MVFR conditions are
forecast within the band. Breezy to windy southwest to west winds
are expected to be strongest this evening.
&&
.PREV DISCUSSION... /issued 328 PM PST Mon Dec 8 2025/
DISCUSSION...
Key Messages:
1. Windy conditions tonight, returning late Tuesday night.
*Wind Advisories Active*
2. Significant rainfall leading to flood concerns through week.
*Flood Watch Issued*
Current radar and visible satellite imagery showing moderate to
heavy rainfall west of the Cascades, with isolated showers passing
through the Columbia Basin under mostly cloudy to cloudy skies.
This is in response to an upper level shortwave and associated
cold front that is passing through the area this evening. The
passing cold front will also tighten the pressure gradient across
the Columbia Basin, providing breezy winds tonight through the
morning hours on Tuesday. The RAP, GFS, and NAM advertise a
gradient of 9.5-11.5 mb between Portland (PDX) and Spokane (GEG),
which relates to sustained southwest winds of 25-35 mph with gusts
of up to 60 mph, peaking between 8PM tonight and 3AM Tuesday
morning. Confidence in these wind speeds is high (75-90%) as the
NBM advertises a 70-95% chance of 50 mph gusts or greater across
the Simcoe Highlands and southern Blue Mountain foothills and a
50-80% chance of 45 mph gusts or greater through the northern Blue
Mountain foothills, Yakima Valley, and the Lower Columbia Basin.
Thus, a Wind Advisory has been issued through 7 AM Tuesday for the
aforementioned areas. Winds will slowly taper off through Tuesday
morning and afternoon before a second cold front passage occurs
late Tuesday night through Wednesday morning, promoting a return
to breezy conditions. This second frontal system is not as strong
as tonight's, as the GFS and NAM indicates a pressure gradient of
8-10 mb. These values relate to sustained southwest winds of 15-25
mph and gusts up to 40 mph, which is below the wind advisory
threshold (45 mph or greater).
The early week system will not only bring windy conditions across
the region, but substantial and widespread rainfall is anticipated
through Wednesday associated with a strong atmospheric river (AR)
event. The ECMWF and GFS ensembles show Precipitable Water (PW)
amounts of around 1 inch, which is 225-250% above normal. The
fetch associated with this AR extends to the date line (~170W),
effectively tapping into subtropical moisture and temperatures. As
a result, snow levels have soared into the 7000-9000 foot range
as high temperatures are breaking into the upper 50s to mid-60s
through the week, which is about 15-25 degrees above normal for
this time of year. These warm temperatures and rain-on-snow
potential due to elevated snow levels will allow rivers and
streams to reach flood levels, especially for the Naches and
Yakima Rivers as the current forecast reaches action stage over
the next 24 hours and peaks in moderate flood stage for the Naches
River near Naches and the Yakima River near Parker and Kiona
Thursday and Friday. Reaches further upstream are expected to
reach minor flood stage over the next 24 hours. As a result, a
Flood Watch has been issued and is in effect through Friday
morning. The Yakima River at Easton has already reached into
action stage, with low-lying and flood prone areas already
experiencing localized flooding. This has warranted the issuance
of a Flood Advisory for the Elk Meadows area near Cle Elum as
flooding is ongoing via contact with the public. In addition to
the Yakima and Naches Rivers, the Klickitat River near Pitt and
the Umatilla River near Gibbon both reach action (bankfull) stage
Wednesday morning. River levels are expected to subside slowly
over the weekend with all reaches currently forecast to fall below
minor flood stage by early Monday morning. 75
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 48 56 45 65 / 70 100 90 40
ALW 50 54 46 64 / 80 90 90 60
PSC 49 56 44 66 / 40 80 90 20
YKM 41 50 39 60 / 80 80 100 60
HRI 50 57 46 66 / 50 90 90 20
ELN 37 46 35 56 / 90 70 100 70
RDM 43 57 44 63 / 50 70 50 10
LGD 45 51 41 58 / 90 100 100 50
GCD 45 51 45 58 / 50 90 70 10
DLS 51 56 48 63 / 90 100 100 70
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory until 7 AM PST Tuesday for ORZ041-044-507-508-510.
WA...Wind Advisory until 7 AM PST Tuesday for WAZ024-027>029-521.
Flood Watch through Friday morning for WAZ026-027-521>523.
&&
$$
DISCUSSION...75
AVIATION...86
