or discuss
Office: MFR
FXUS66 KMFR 092222
AFDMFR
Area Forecast Discussion
National Weather Service Medford OR
222 PM PST Tue Dec 9 2025
.DISCUSSION (Today through Monday)...
Key Points:
* Overall, minimal weather impacts through this weekend
* Mostly light rainfall chances expected through Wednesday
- No snow expected
* Next widespread chance for precipitation is early next week
- Could be as early as Sunday
- Snow: Snow levels are high 6,000+ ft
- Little to no snow accumulation expected
- Rain: Mainly for Coastal areas, Cascades, & Umpqua Basin
- Highest chances for accumulation of at least 0.25"/24hrs
- Wind: Advisory level wind speeds possible early next week
- Mainly eastside areas and Shasta Valley
Further Details:
Our weather across the PacNW is being dictated by an area of low
pressure over the Gulf of Alaska and high pressure off the coast of
California. This is allowing for a large swath of moisture advection
into the region between these two features. By far and large, nearly
all the weather impacts will be north of our forecast area. In other
words, we are only expecting light rainfall through Wednesday given
the strength and placement of the high pressure. Additionally, we
will have wind advisory conditions over parts of the eastside
through this evening. Eventually, the ridge of high pressure does
break down, and the orientation shifts to allow this moisture
plume to go farther north into Canada Thursday through Sunday.
Through this stretch, we are expecting dry conditions across the
forecast area. There is some uncertainty on the next potential
area of low pressure impacting the region, and it could be as
early as Sunday. Deterministic and ensemble members have a strong
signal for rainfall chances increasing by Monday. Snow levels are
really high early next week, and at this time very little snowfall
is anticipated. Cluster analysis shows a split with 5000mb
heights early next week. This doesn't lead to high confidence with
some of the exact details, but at this time there isn't a lot of
confidence for impactful weather through early next week. The
probability for at least 2.0" of snow over 24 hours is only around
20% Mon/Tues for areas in/around Crater Lake. In fact, most
ensemble members have zero snowfall at Crater Lake through early
next week. We are going to need the pattern to shift in a way that
allows colder Arctic/Canadian air to advect into the region, but
this doesn't look promising through next week. For perspective,
the latest Crater Lake has had zero snow depth was December 26th,
1976. Record keeping began in 1919 for Crater Lake, and we have
only had 9 years where we went into December for the last snow
depth of zero. This will be the 10th year, and will likely rank at
least 3rd latest ever. In 1958, we went until December 20th, and
in 2008 we went until December 11th.
-Guerrero
&&
.AVIATION (00Z TAFs)...
Rain showers are still expected through early parts of this TAF
cycle which will mainly impact KOTH, but there will be showers
around KRBG and KMFR as well. Overall, this will be mostly a MVFR
to IFR/LIFR TAF cycle as ceilings reduce overnight in addition to
visibilities. High confidence (50%-70%) for IFR/LIFR conditions
overnight. The one caveat is KLMT which will have the highest
uncertainty for IFR/LIFR, but overall conditions will deteriorate
overnight across the area with fog/low clouds.
-Guerrero
&&
.MARINE...Updated 230 PM PST Tuesday, December 9, 2025...Gusty
south winds and steep wind waves combined with westerly swell will
maintain conditions hazardous to small craft through this evening.
Winds subside tonight, but west swell persists into Wednesday,
especially north of Cape Blanco and high steep will continue to pose
a threat to smaller crafts. Conditions improve for the latter half
of the week as high pressure builds over the region. 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.
-Smith
&&
.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 092351
AFDPQR
Area Forecast Discussion
National Weather Service Portland OR
351 PM PST Tue Dec 9 2025
.SYNOPSIS...A prolonged atmospheric river continues to
influence the Pacific Northwest, sustaining periods of heavy
rainfall, breezy winds, and widespread hydrologic concerns
through late Wednesday, possibly as late as early Thursday.
Widespread river flooding remains likely, 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.
&&
.DISCUSSION...Now through Monday...The strong atmospheric river
(AR) event continues across northwest Oregon and southwest
Washington. Significant rainfall will continue to bring
flooding of rivers, creeks, streams, and other low-lying and
flood-prone locations through at least Wednesday. Concerns for
landslides and debris flows remain as soils remain saturated.
Since midnight on Mon, Dec 8th (the beginning of the event),
weather stations have reported rainfall totals of 4 to 7 inches
across the the north Oregon Coast Range, Willapa Hills, south
Washington Cascades, and north Oregon Cascades, 3 to 5 inches
across the Cowlitz Valley, Clark County lowlands, north Oregon
coast, and south Washington coast, 1 to 2.25 inches across the
central and northern Willamette Valley, and 0.50 to 1 inch in
the southern Willamette Valley.
Moisture from this AR has briefly shifted southward today, with
much of the rain falling across northwest Oregon. Mesoanalysis
as of Tuesday afternoon shows a warm front approaching the
Pacific Northwest, which will gradually shift rain northward
into southwest Washington and far northwest Oregon. This will be
the second round of impactful rain from this AR. The heaviest
rain tonight into early Wednesday morning will be over the Coast
Range, Willapa Hills, south Washington Cascades, and north
Oregon Cascades. Moderate to high confidence (50-70% chance)
that these areas will receive an additional 4 to 6 inches of
rain from this afternoon to 4 AM Thursday, with a 10-20% chance
for locally higher amounts of 7+ inches. This will further
exacerbate flood impacts considering the amount of rain that has
already fallen.
Meanwhile, high resolution guidance suggests a rain shadowing
effect will keep rainfall amounts lower for interior lowland
valleys. Forecast amounts are around 0.10 to 0.25 inches across
the Willamette Valley and most southwest Washington lowlands.
Based on REFS guidance, chances for 0.5 inch of rain or more
across interior valleys are only 5-15%, highest across the
Portland/Vancouver Metro and northern Clark County lowlands. An
exception is the far northern Cowlitz Valley where there is a
50-60% chance for an additional 1 inch of rain of greater north
of Kelso/Longview through Wednesday afternoon.
Snow levels remain high, holding near or above 8000 ft through
at least Wednesday, maintaining rain in the Cascades and
further contributing to elevated runoff and river responses. A
gradual downward trend in snow levels is likely late Wednesday
night.
Winds remain a secondary hazard and continue to carry relevance
given soil saturation. Winds will gradually increase overnight
as this next front moves in. Southwesterly winds will be breezy
with gusts up to 25 to 30 mph for interior valleys, and 35 to 45
mph for across the Coast Range, Willapa Hills, south Washington
Cascades, north Oregon Cascades, and ridgetops surrounding the
Columbia River Gorge. Due to saturated soils, even moderate
wind gusts may be capable of uprooting trees or power lines.
Therefore, a Wind Advisory has been issued for much of northwest
Oregon through Wednesday evening.
The atmospheric river weakens late Wednesday as moisture
transport decreases and the plume begins to dissipate. Showers
will persist into Thursday, though rainfall intensity will be
much lighter and increasingly confined to higher terrain across
southwest Washington and the north Oregon Coast Range. A more
stable pattern develops Friday into Saturday as high pressure
builds, leading to a notable drying trend. Snow levels gradually
lower to around 5500 to 6500 ft through the weekend. Despite
the improving weather, hydrologic impacts for slow-responding
rivers may linger a bit longer. Soils will remain saturated,
particularly across the Coast Range and Cascades, leaving the
region sensitive to additional rainfall. Additional frontal
system look to arrive early next week. -10/12
&&
.AVIATION...A mixed bag of LIFR/IFR/MVFR cigs and IFR/MVFR/VFR
visibilities continues across northwest Oregon and southwest
Washington, with cigs and visibilities being lowest from KONP to
KSLE and points north where a large band of steady stratiform
rain continues. Rain will be heavy at times through Tuesday
afternoon, especially during the morning and early afternoon
hours north of KEUG. Rain should finally begin to taper off from
south to north between 06-12z Wednesday as the aforementioned
band of stratiform rain lifts northward over western Washington.
Although winds have become less gusty, occasional wind gusts up
to 20-25 kt are still being observed inland and up to 30 kt at
KONP. Winds will increase along the coast through the day,
especially at KONP where wind gusts will likely approach 35-40
kt. The remaining TAF sites will see wind gusts increasing late
this afternoon into tonight.
KPDX AND APPROACHES...Expect steady stratiform rain to persist
through at least 00z Wednesday, heavy at times this morning
before rain attempts becoming relatively light this evening.
This will result in development of MVFR cigs between 18-21Z,
then persisting throughout the TAF period, with occasional dips
to IFR possible (20-35% chance) through 00z Wednesday, and then
to 60-70% by 01z. Although winds have weakened this morning,
expect winds to increase again towards 02-06z Wednesday when
southerly to southwesterly wind gusts up to 25-30 kt are likely.
&&
.MARINE...Seas are in the 12-13 ft range this afternoon. Winds,
which died off a bit this morning, are ramping up again this
afternoon and will continue to do so tonight as a stronger
frontal system moves in. This will cause gales (gusts to 40 kt)
and steep to very steep seas over the inner waters into
Wednesday. Gusts of 30 kt are expected over the outer waters
with a low chance (30%) of gale force gusts (35 kt). This
increase in wind could result in significant wave heights
peaking around 14 feet through Wednesday evening. Gales end by
Wednesday evening, but steep seas likely continue, so we'll
likely need to extend the small craft advisory into Thursday
morning. Seas gradually fall below 10 feet Thursday afternoon
with relatively quiet conditions expected over the coastal
waters Friday and most the weekend. Latest guidance is showing
the next chance for stronger winds and higher seas late Sunday
night into Monday. -Spilde
&&
.BEACH HAZARDS...Tidal overflow continues to be a threat to the
coastal communities of south Washington, north Oregon and
central Oregon. While tidal stages may be below typical
markers for traditional tidal overflow, the increase in flow of
area rivers increases the probability for overflow. Tidal
overflow concerns remain for this afternoon's high tide, then
will surge again during Wednesday afternoon's high tide. The
Toke Point tidal gauge is expected to peak near 9.5 ft around
3-4 PM Wednesday and the Willapa River will likely remain above
80% of flood flow during high tide. Therefore, the Coastal Flood
Advisory has been extended for the high tide on Wednesday.
There remains 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, which are waves that can run
significantly farther up a beach than normal, including over
rocks and jetties. Sneaker waves can suddenly knock beachgoers
off of 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. -27
&&
.HYDROLOGY...A strong atmospheric river remains in place across
southwest Washington and northwest Oregon this morning,
maintaining an elevated threat of urban, river, and small stream
flooding through at least late Wednesday. Significant rainfall
has already fallen across much of the region since early Monday,
and river responses are now well underway. Additional rainfall
today through Wednesday from the second moisture surge will
prolong elevated flows, with many rivers already exceeding flood
stage, or forecast to exceed flood stage within the next 24-36
hours.
Rainfall over the past 24 to 36 hours has already pushed several
rivers into flood stage, including record flooding on the Grays
River (the old record height was 33.15 ft, which was broken
around 10 PM Monday when river levels peaked around 33.4 ft),
major flooding on the Naselle River, moderate flooding on the
Willapa River, and minor flooding for Nehalem River, Wilson
River, Trask River, Beaver Creek, East Fork Lewis River, Miami
River, and Washougal River. Elsewhere, many basins continue
rising and are expected to respond sharply again as periods of
heavy rain continue. While the Siletz River, Cowlitz River
(Kelso and Castle Rock), and Johnson Creek are currently not in
flood stage or action stage, these rivers are expected to reach
minor flood stage late this morning. Expect the Pudding River to
reach minor flood stage by late Wednesday.
The threat for flooding along small creeks and streams as well
as urban flooding, including roadway flooding, will continue
through Wednesday. Latest high-resolution guidance favors a band
of heavier precipitation lingering over southwestern Washington
and far northwestern Oregon this morning, with rates around
0.25 inch per hour or higher. These 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. Ponding of water on roads
will increase risk of hydroplaning and car accidents.
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 landslides. A Flood
Watch remains in effect across all of southwest Washington and
northwest Oregon from now until 4 PM Thursday, except for most
of Lane County which has been removed from the Flood Watch.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...Coastal Flood Advisory until 5 PM PST this afternoon for ORZ101-
102.
Wind Advisory until 10 PM PST Wednesday for ORZ104>115-123.
WA...Coastal Flood Advisory until 5 PM PST this afternoon for WAZ201.
Wind Advisory until 10 PM PST Wednesday for WAZ202>208.
PZ...Small Craft Advisory until 4 PM PST this afternoon for PZZ210-
251-252.
Gale Warning until 10 PM PST Wednesday for PZZ210-251-252.
Gale Warning until 4 AM PST Wednesday for PZZ253.
Small Craft Advisory from 4 AM to 10 PM PST Wednesday for PZZ253.
Small Craft Advisory until 10 PM PST Wednesday for PZZ271>273.
&&
$$
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Office: PDT
FXUS66 KPDT 092314
AFDPDT
Area Forecast Discussion
National Weather Service Pendleton OR
314 PM PST Tue Dec 9 2025
Updated Aviation Discussion
.AVIATION...00z TAFs...Variable conditions will materialize this
evening as another round of rain showers develop over primarily
the Basin and adjacent valleys. MVFR conditions are possible
(40-50% chance) under rain showers. BDN and RDM are largely
expected to be spared of rain through the period, outside of trace
amounts. Once rain tapers off by around midnight, winds will start
to pick up by sunrise Wednesday. Gusts could reach 30 kts at many
sites, possibly as high as 40 kts in sites across the Basin
(30-40% chance). Cigs will transition from low to mid bkn-ovc this
evening to sct-bkn mid cigs during the day tomorrow. 74
&&
.PREV DISCUSSION... /issued 242 PM PST Tue Dec 9 2025/
Key Messages...
- Excessive Rainfall in the elevated category across the
Washington Cascades with numerous flooding impacts continuing .
- Breezy to Windy conditions beginning overnight and lasting
though Thursday.
- Warmer than normal temperatures are expected in the extended
periods.
DISCUSSION...
The synoptic setup shows a trough of low pressure lifting into BC
as a warm front spreads north across WA/OR Today. An Atmospheric
River will remain relevant to the sensible weather Tonight,
lifting northward and spreading more rain along the frontal
boundary. As the AR weakens Tonight and Wednesday , precipitation
will become more relegated to the Cascade Caps and eastern
Mountains, continuing to aggravate the recent onset of flooding
across the Yakima Valley.
Additional river flooding risk will continue along rivers of the
Yakima valley Tonight as excessive rainfall across the Washington
Cascades remains in the elevated category. This is due to a
combination of runoff from rains along the lowers lower slopes of
1 to 2 inches and several inches from the Upper Slopes.
Breezy to windy conditions are anticipated across the entire area
as a warm front lifts across the area Tonight. The potential for
sustained winds greater than 30 mph ramps up to around 60-80
percent by the overnight hours. This will bring the need for wind
advisories focused large on the lower Columbia Basin of WA, the
Simcoe Highlands as well as the Foothills of the Northern Blues.
The advisory has been issued for these areas beginning 6 am
Wednesday and lasting through 9 am Thursday.
Temperatures with the westerly flow will be markedly warmer in
the lowlands of the Columbia Basins and central Oregon/John Day
basin, and typically well into the 60s Wednesday and into
Thursday.
The AR weakens with midweek, however enough moisture transport
appears available to maintain and slight risk (15% chance of
exceeding flash flood guidance) west of a line from Wenatchee to
Hood River through the day on Wednesday. Risk ramps down on
Thursday, but a 5% chance for these conditions persist for the
Upper Slopes. An areal flood watch is in place for much of
Kittitas, Yakima and Klickitat counties through Friday morning.
Russell/71
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 46 64 51 61 / 90 40 10 20
ALW 48 63 53 60 / 100 60 20 40
PSC 46 65 54 63 / 100 20 10 20
YKM 41 63 48 59 / 100 60 50 40
HRI 46 66 53 62 / 90 20 10 20
ELN 37 58 43 52 / 100 70 60 60
RDM 44 62 36 59 / 50 10 0 10
LGD 43 59 46 56 / 100 50 10 30
GCD 45 58 39 56 / 80 10 0 10
DLS 48 63 53 61 / 100 70 70 60
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory from 6 AM Wednesday to 7 AM PST Thursday for
ORZ041-044-507-508-510.
WA...Wind Advisory from 6 AM Wednesday to 7 AM PST Thursday for
WAZ024-027>029-521.
Flood Watch through Friday morning for WAZ026-027-521>523.
&&
$$
DISCUSSION....71
AVIATION...74
