or discuss
Office: MFR
FXUS66 KMFR 080543
AFDMFR
Area Forecast Discussion
National Weather Service Medford OR
943 PM PST Sun Dec 7 2025
.Updated AVIATION and MARINE Discussions...
&&
.AVIATION...08/06z TAFs...Plenty of cloud cover is resulting in a
variety of conditions across the region with widespread terrain
obscurations present. Not much change in overall conditions is
expected into Monday morning. Areas of precipitation are bringing a
mix of LIFR/IFR conditions along the coast, MVFR conditions in the
Umpqua Basin and Illinois Valley, and VFR conditions for the
remainder of the region. Depending on any level of clearing this
overnight, LIFR conditions could develop in West Side Valleys, but
cloud cover is expected to be persistent enough to at least limit
development and extent of these LIFR conditions.
Moderate to strong winds aloft will result in mountain wave
turbulence along and east of the Cascades with stronger winds near
and at the ridges. /BR-y
&&
.MARINE...Updated 800 PM PST Sunday, December 7, 2025...South winds
will persist overnight, with steep seas continuing north of Cape
Blanco into Monday morning. Conditions worsen late Monday morning as
southerly winds increase, especially north of Cape Blanco, and steep
seas spread to all areas. Advisory level conditions are expected
through Tuesday, and winds could approach gales late Monday into
early Tuesday north of Cape Blanco. Conditions improve around mid-
week as winds ease and seas become swell dominated.
&&
.PREV DISCUSSION... /Issued 346 PM PST Sun Dec 7 2025/
DISCUSSION...While a very heavy rain/flooding event is expected
to materialize to our north through midweek, our forecast area in
SW Oregon and NorCal will largely dodge those threats. We'll
explain the reasons for that below. Please continue to follow NWS
Portland and Seattle for the details on how much rain and the
associated flooding risks up there.
Currently, a weak disturbance is moving through our area today,
and is bringing a little light rain/drizzle from the
Siskiyous/Cascades north/west to the coast. A few drips may also
occur in Siskiyou County. Amounts so far though, as of 1 pm PST,
have been generally light -- 0.01-0.10" in most areas, but 0.34"
at Charlotte Ridge RAWS and up to 0.59" at Burnt Ridge RAWS. Snow
levels are generally around 7000 feet. Expect mostly intermittent
light rain/drizzle to continue tonight across NW sections of the
CWA. Meanwhile, SE areas like Alturas and even most areas east of
the Cascades in Oregon will stay dry.
On Monday, a deep plume of subtropical moisture, or atmospheric
river, will gather over the Pacific and become directed into
British Columbia, Washington and NW Oregon. This will set the
stage for the prolonged period of heavy rainfall for our neighbors
to the north. Our forecast area will be largely spared of the
impacts though. This is primarily due to the strength of an upper
level high centered near 30N and 130W (off the California Coast).
This high will remain strong enough to deflect most of that moist
plume off to our north. The main source of uncertainty has been
the strength of this high and just how far south the moist plume
could jog Monday night to Wednesday. Models are trending farther
north (at least in terms of QPF) compared to yesterday. 12Z GEFS
solutions have come more in line with the ECMWF and now show very
little rain even here in Medford with rain shadowing significantly
impacting amounts south of Roseburg. Favored areas along the
coast and over to the Cascades as well as north of Roseburg along
the Douglas/Lane County border still could see amounts of 1-3
inches during that time period, but we're not concerned about
flooding. We issued a Hydrological Outlook yesterday to raise
awareness of the risks, but we'll allow that to expire this
evening.
One thing that continues to be shown is a fairly strong gradient
and mid-level jet (55-65kt) across the Cascades that could lead
to stronger winds east of the Cascades in Oregon and north of
Highway 140 beginning Monday night and continuing through Tuesday
evening. Not completely sure these strong winds aloft mix down to
the surface, but could at the higher terrain and locally
channeled valleys like around Summer Lake. As such, have gone
with a wind advisory for those locations 7 pm PST Monday through
10 pm PST Tuesday for gusts up to 50 mph.
After Wednesday, the upper ridge off the California coast is expected
to amplify and that should push the front well off to our north
and bring a period of dry weather to most, if not all, of the
area Thursday into the weekend. Slight chance PoPs remain along
the coast, but wouldn't be surprised to see these fall out of the
forecast. Some guidance breaks down the ridge over the weekend
with a front reaching the coast sometime Saturday night, but most
hold this front off until later in the weekend or early next week.
This will maintain the milder pattern through at least mid-month.
-Spilde
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory from 7 PM Monday to 10 PM PST Tuesday for ORZ030-
031.
CA...None.
PACIFIC COASTAL WATERS...Small Craft Advisory from 10 AM Monday to 1
PM PST Tuesday for PZZ356-376.
Small Craft Advisory until 1 PM PST Tuesday for PZZ350-370.
&&
$$
Office: PQR
FXUS66 KPQR 080525 AAA
AFDPQR
Area Forecast Discussion...UPDATED
National Weather Service Portland OR
925 PM PST Sun Dec 7 2025
Updated aviation, marine, and hydrology discussions.
.SYNOPSIS...
A steady, moisture-rich pattern continues through
midweek as two strong atmospheric river surges arrive Monday and
again Tuesday night to Wednesday. Conditions become increasingly
impactful Monday and Tuesday as deep subtropical moisture and
stronger winds move inland. River rises and localized flooding will
need close attention through the week. Gusty winds are also expected
and could bring down trees and cause power outages.
&&
.DISCUSSION...Today through Saturday...Scattered showers perish
across the area as a weak disturbance continues to move across the
region, a quiet precursor to the more impactful weather system that
moves in overnight.
The overall pattern remains basically the same from previous
forecasts with slight changes in rainfall totals and where impacts
are expected. The synoptic set-up for the week starts with a ridge
of high pressure centered over the Pacific between Hawaii and
southern California. Clockwise circulation will advect sub-tropical
moisture northward toward the PacNW in several round between Monday
and Wednesday night. Mid level flow will predominantly be zonal as
the top of the ridge extends northward along the West Coast. At the
same time, several troughs will support surface lows and cold fronts
that will provide lift over the region. The first slug of AR
moisture enters the picture late tonight into Monday with IVT values
along the coast peaking between 750-1000 kg/ms and values inland
peaking between 500-750 kg/ms. This round of rain will be falling on
already saturated soil, WPC has maintained the Slight/Marginal ERO
risk over the CWA. The slight risk covers all of SW WA, down the
coast range in OR and along the Cascades down to around Santiam
pass. A couple of changes to note with this first round are the
slight northward shift in the highest IVT values, leading to changes
in the total QPF Monday through Tuesday. Totals across the southern
Willamette Valley and Lane County Cascades and Coast Range have
dropped slightly while totals over southwest Washington areas
generally north of Salem have increased slightly. While this has not
caused major changes in expected impacts, several river forecasts
have seen increases in flooding potential. More details are included
in the hydrology section below.
The second round of high IVT values is expected to impact the region
Tuesday night into Wednesday. IVT Values look similar to the first
round, maybe a touch lower which will lead to slightly lower
rainfall totals. Rainfall is still expected to be heavy with this
second round, regardless of whether it reaches the same level as the
fist round. Expect continued urban and river flooding issues at
least through Wednesday.
Winds will be a concern Monday through Wednesday, with gusts up to
at least 30 mph inland and up to at least 40 mph at the coast. Given
the soils are already saturate and heavy rain with gusty winds is
expected, a Wind Advisory has been issued for potential impacts. The
advisory covers the OR and WA Coast Range, Willamette Valley from
Salem northward through the Portland/Vancouver Metro, I-5 corridor
in WA, and the Cascade Foothills north of Salem. Saturated soils
will see persistent rain and eventually gusty winds, resulting in
downed trees and possibly power outages. Confidence in impacts
occurring is high but confidence in exact location and extent of
impacts is low.
Snow levels will remain well above 6000 ft through midweek due to
the warm subtropical air mass, ensuring that nearly all
precipitation in the Cascades falls as rain. By Thursday and Friday,
the moisture plume weakens and transitions toward a showery pattern.
Conditions will gradually ease, but rivers and soils will remain
sensitive due to cumulative rainfall. -19/12
&&
.AVIATION...The warm frontal boundary continues to shift towards
the region overnight. Will see an increase of cloud cover and more
widespread MVFR conditions. Showers will begin to intensify by 15Z
Mon which will persist for a prolonged period of time. With the
heavy rain and reduced CIGs, expecting widespread MVFR conditions
if not IFR along the coast. With the frontal system will see
strong south to southwesterly winds. Gusts as high as 40 kt
possible along the coast with increasing chances for gusts around
30 kt within the Willamette Valley. The Columbia River Gorge and
foothills will see less wind though will remain elevated. These
winds will be coupled through the atmosphere so approaches too
will be impacted.
KPDX AND APPROACHES...VFR conditions prevail until around 09-12z
when MVFR ceilings are expected to return. Scattered showers are
possible through the night. A frontal system will bring
increasing rain after 14z Monday with lowered visibilities. South
winds will increase with gusts up to 25-30 kts after 14z. -27/03
&&
.MARINE...Winds have decreased substantially this afternoon behind
this morning's frontal system, and will continue to decrease into
the evening. There will be a brief period of benign conditions
tonight with wind gusts below 20 kts and seas under 8-9 ft.
A stronger frontal system is set to arrive early Monday, bringing
gale force wind gusts up to 35-45 kt, strongest over the inner
waters and near the Columbia River Bar. A Gale Warning is in
effect from 3 AM Monday to 1 AM Tuesday as probabilities for gale
force gusts are up to 80-90%. With the increasing winds, seas will
become steep and hazardous Monday afternoon into Monday night.
Expect seas to peak somewhere between 14 to 17 ft.
Winds decrease from north to south late Monday night into Tuesday
morning with gusts falling below 20 kts everywhere except for
portions of zones PZZ273 and PZZ253 briefly on Tuesday morning.
Then another frontal system moves through the waters Tuesday
afternoon into Wednesday, causing increasing southwesterly winds
with gusts up to 25-30 kt likely. There's around a 20% chance of
occasional gale force wind gusts over 34 kts across the waters
Tuesday night, though it is not expected to have widespread gale
force gusts for a long enough period of time at this moment. Seas
also decrease slightly Tuesday into Wednesday but remain above 10
ft. Seas and winds subside late in the week. -23/03
&&
.BEACH HAZARDS...
Tidal overflow flooding around high tide is
likely on Monday, December 8 and 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 Monday 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 has been issued from 2 PM to 6 PM PST
Monday. Uncertainty remains on whether a Coastal Flood Advisory
will be needed on Tuesday because even though there is high
confidence that coastal rivers will be above 80% of flood flow
during high tide, the total tide forecast is below 9.5 ft at most
tidal points. Will continue to monitor the tidal forecast 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
14-15 seconds with swell heights around 9-11 ft with both
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. -03
&&
.HYDROLOGY...A series of frontal systems will keep conditions
very wet through the weekend and much of next week. The most
notable period will be late Monday through late Wednesday, when
a prolonged atmospheric river will bring significant rainfall
and the potential for widespread river flooding across southwest
Washington and northwest Oregon. There is a 10% chance for rain
amounts up to 10 inches in the Cascades and Coast Range, up to
8-10 inches at the coast, and up to 7.5-8.5 inches in the
Willamette Valley, Portland/Vancouver metro and Cowlitz Valley.
While rain amounts this high are unlikely to occur, they
represent a reasonable worst case scenario. This outcome would
result in widespread major flooding.
Although rain will likely become lighter Thursday into Friday,
the threat of flooding will linger along slow responding rivers.
Rivers draining the Coast Range and Willapa Hills have a 30-60%
chance of reaching moderate flood stage and a 20-40% chance of
reaching major flood stage. Additionally, many Willamette River
tributaries that drain from the Coast Range and Cascades have
anywhere from a 40-70% chance of reaching minor flood stage and
a 20-50% chance of reaching moderate flood stage. Flooding of
the Willamette mainstem rivers is unlikely to occur (less than
10%). Probabilities for specific river points can be found at
the National Water Prediction Service website.
There is also increasing confidence in the potential for
flooding along small creeks and streams as well as urban
flooding, including roadway flooding. 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 for all of southwest Washington and
northwest Oregon from 4 AM Monday to 4 AM Friday. Considering
increased confidence and probabilities for flooding of rivers
and urban areas as the forecasted event approaches, a Flood
Warning has been issued for the following rivers.
Wilson River near Tillamook affecting Tillamook County, from
Monday evening to late Tuesday morning. There is a 75% chance of
reaching moderate flooding and a 50% chance of reaching major
flooding. Grays River at Covered Bridge near Rosburg affecting
Wahkiakum County, from Monday evening to early Thursday morning.
There is a 70% chance of reaching moderate flooding and a 50%
chance of reaching major flooding. Johnson Creek at Sycamore
affecting Clackamas and Multnomah Counties, from Monday evening
to late Wednesday evening. There is a 70% chance of reaching
moderate flooding, and a 60% chance of reaching major flooding.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...Coastal Flood Advisory from 2 PM to 6 PM PST Monday for ORZ101-
102.
Wind Advisory from 7 AM Monday to 4 AM PST Tuesday for
ORZ104>115-123.
WA...Coastal Flood Advisory from 2 PM to 6 PM PST Monday for WAZ201.
Wind Advisory from 7 AM Monday to 4 AM PST Tuesday for
WAZ202>208.
PZ...Gale Warning from 3 AM Monday to 1 AM PST Tuesday for PZZ210-
251-271.
Gale Warning from 3 AM Monday to 7 AM PST Tuesday for PZZ252-
253-272-273.
&&
$$
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FXUS66 KPQR 080530 AAA
AFDPQR
Area Forecast Discussion...UPDATED
National Weather Service Portland OR
930 PM PST Sun Dec 7 2025
Updated aviation, marine, and hydrology discussions.
.SYNOPSIS...
A steady, moisture-rich pattern continues through
midweek as two strong atmospheric river surges arrive Monday and
again Tuesday night to Wednesday. Conditions become increasingly
impactful Monday and Tuesday as deep subtropical moisture and
stronger winds move inland. River rises and localized flooding will
need close attention through the week. Gusty winds are also expected
and could bring down trees and cause power outages.
&&
.DISCUSSION...Today through Saturday...Scattered showers perish
across the area as a weak disturbance continues to move across the
region, a quiet precursor to the more impactful weather system that
moves in overnight.
The overall pattern remains basically the same from previous
forecasts with slight changes in rainfall totals and where impacts
are expected. The synoptic set-up for the week starts with a ridge
of high pressure centered over the Pacific between Hawaii and
southern California. Clockwise circulation will advect sub-tropical
moisture northward toward the PacNW in several round between Monday
and Wednesday night. Mid level flow will predominantly be zonal as
the top of the ridge extends northward along the West Coast. At the
same time, several troughs will support surface lows and cold fronts
that will provide lift over the region. The first slug of AR
moisture enters the picture late tonight into Monday with IVT values
along the coast peaking between 750-1000 kg/ms and values inland
peaking between 500-750 kg/ms. This round of rain will be falling on
already saturated soil, WPC has maintained the Slight/Marginal ERO
risk over the CWA. The slight risk covers all of SW WA, down the
coast range in OR and along the Cascades down to around Santiam
pass. A couple of changes to note with this first round are the
slight northward shift in the highest IVT values, leading to changes
in the total QPF Monday through Tuesday. Totals across the southern
Willamette Valley and Lane County Cascades and Coast Range have
dropped slightly while totals over southwest Washington areas
generally north of Salem have increased slightly. While this has not
caused major changes in expected impacts, several river forecasts
have seen increases in flooding potential. More details are included
in the hydrology section below.
The second round of high IVT values is expected to impact the region
Tuesday night into Wednesday. IVT Values look similar to the first
round, maybe a touch lower which will lead to slightly lower
rainfall totals. Rainfall is still expected to be heavy with this
second round, regardless of whether it reaches the same level as the
fist round. Expect continued urban and river flooding issues at
least through Wednesday.
Winds will be a concern Monday through Wednesday, with gusts up to
at least 30 mph inland and up to at least 40 mph at the coast. Given
the soils are already saturate and heavy rain with gusty winds is
expected, a Wind Advisory has been issued for potential impacts. The
advisory covers the OR and WA Coast Range, Willamette Valley from
Salem northward through the Portland/Vancouver Metro, I-5 corridor
in WA, and the Cascade Foothills north of Salem. Saturated soils
will see persistent rain and eventually gusty winds, resulting in
downed trees and possibly power outages. Confidence in impacts
occurring is high but confidence in exact location and extent of
impacts is low.
Snow levels will remain well above 6000 ft through midweek due to
the warm subtropical air mass, ensuring that nearly all
precipitation in the Cascades falls as rain. By Thursday and Friday,
the moisture plume weakens and transitions toward a showery pattern.
Conditions will gradually ease, but rivers and soils will remain
sensitive due to cumulative rainfall. -19/12
&&
.AVIATION...The warm frontal boundary continues to shift towards
the region overnight. Will see an increase of cloud cover and more
widespread MVFR conditions. Showers will begin to intensify by 15Z
Mon which will persist for a prolonged period of time. With the
heavy rain and reduced CIGs, expecting widespread MVFR conditions
if not IFR along the coast. With the frontal system will see
strong south to southwesterly winds. Gusts as high as 40 kt
possible along the coast with increasing chances for gusts around
30 kt within the Willamette Valley. The Columbia River Gorge and
foothills will see less wind though will remain elevated. These
winds will be coupled through the atmosphere so approaches too
will be impacted. At around 2000 ft, wind speeds will be southwest
with speeds up to 50 kt. Some models are suggesting gusts as high as
65 kt but those would be isolated. Therefore, have included the
mention of LLWS in some area TAFs.
KPDX AND APPROACHES...VFR conditions prevail until around 09-12z
when MVFR ceilings are expected to return. Scattered showers are
possible through the night. A frontal system will bring
increasing rain after 14z Monday with lowered visibilities. South
winds will increase with gusts up to 25-30 kts after 14z. -27/03
&&
.MARINE...Winds have decreased substantially this afternoon behind
this morning's frontal system, and will continue to decrease into
the evening. There will be a brief period of benign conditions
tonight with wind gusts below 20 kts and seas under 8-9 ft.
A stronger frontal system is set to arrive early Monday, bringing
gale force wind gusts up to 35-45 kt, strongest over the inner
waters and near the Columbia River Bar. A Gale Warning is in
effect from 3 AM Monday to 1 AM Tuesday as probabilities for gale
force gusts are up to 80-90%. With the increasing winds, seas will
become steep and hazardous Monday afternoon into Monday night.
Expect seas to peak somewhere between 14 to 17 ft.
Winds decrease from north to south late Monday night into Tuesday
morning with gusts falling below 20 kts everywhere except for
portions of zones PZZ273 and PZZ253 briefly on Tuesday morning.
Then another frontal system moves through the waters Tuesday
afternoon into Wednesday, causing increasing southwesterly winds
with gusts up to 25-30 kt likely. There's around a 20% chance of
occasional gale force wind gusts over 34 kts across the waters
Tuesday night, though it is not expected to have widespread gale
force gusts for a long enough period of time at this moment. Seas
also decrease slightly Tuesday into Wednesday but remain above 10
ft. Seas and winds subside late in the week. -23/03
&&
.BEACH HAZARDS...
Tidal overflow flooding around high tide is
likely on Monday, December 8 and 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 Monday 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 has been issued from 2 PM to 6 PM PST
Monday. Uncertainty remains on whether a Coastal Flood Advisory
will be needed on Tuesday because even though there is high
confidence that coastal rivers will be above 80% of flood flow
during high tide, the total tide forecast is below 9.5 ft at most
tidal points. Will continue to monitor the tidal forecast 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
14-15 seconds with swell heights around 9-11 ft with both
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. -03
&&
.HYDROLOGY...A series of frontal systems will keep conditions
very wet through the weekend and much of next week. The most
notable period will be late Monday through late Wednesday, when
a prolonged atmospheric river will bring significant rainfall
and the potential for widespread river flooding across southwest
Washington and northwest Oregon. There is a 10% chance for rain
amounts up to 10 inches in the Cascades and Coast Range, up to
8-10 inches at the coast, and up to 7.5-8.5 inches in the
Willamette Valley, Portland/Vancouver metro and Cowlitz Valley.
While rain amounts this high are unlikely to occur, they
represent a reasonable worst case scenario. This outcome would
result in widespread major flooding.
Although rain will likely become lighter Thursday into Friday,
the threat of flooding will linger along slow responding rivers.
Rivers draining the Coast Range and Willapa Hills have a 30-60%
chance of reaching moderate flood stage and a 20-40% chance of
reaching major flood stage. Additionally, many Willamette River
tributaries that drain from the Coast Range and Cascades have
anywhere from a 40-70% chance of reaching minor flood stage and
a 20-50% chance of reaching moderate flood stage. Flooding of
the Willamette mainstem rivers is unlikely to occur (less than
10%). Probabilities for specific river points can be found at
the National Water Prediction Service website.
There is also increasing confidence in the potential for
flooding along small creeks and streams as well as urban
flooding, including roadway flooding. 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 for all of southwest Washington and
northwest Oregon from 4 AM Monday to 4 AM Friday. Considering
increased confidence and probabilities for flooding of rivers
and urban areas as the forecasted event approaches, a Flood
Warning has been issued for the following rivers.
Wilson River near Tillamook affecting Tillamook County, from
Monday evening to late Tuesday morning. There is a 75% chance of
reaching moderate flooding and a 50% chance of reaching major
flooding. Grays River at Covered Bridge near Rosburg affecting
Wahkiakum County, from Monday evening to early Thursday morning.
There is a 70% chance of reaching moderate flooding and a 50%
chance of reaching major flooding. Johnson Creek at Sycamore
affecting Clackamas and Multnomah Counties, from Monday evening
to late Wednesday evening. There is a 70% chance of reaching
moderate flooding, and a 60% chance of reaching major flooding.
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...Coastal Flood Advisory from 2 PM to 6 PM PST Monday for ORZ101-
102.
Wind Advisory from 7 AM Monday to 4 AM PST Tuesday for
ORZ104>115-123.
WA...Coastal Flood Advisory from 2 PM to 6 PM PST Monday for WAZ201.
Wind Advisory from 7 AM Monday to 4 AM PST Tuesday for
WAZ202>208.
PZ...Gale Warning from 3 AM Monday to 1 AM PST Tuesday for PZZ210-
251-271.
Gale Warning from 3 AM Monday to 7 AM PST Tuesday for PZZ252-
253-272-273.
&&
$$
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Office: PDT
FXUS66 KPDT 080549
AFDPDT
Area Forecast Discussion
National Weather Service Pendleton OR
949 PM PST Sun Dec 7 2025
.AVIATION...
A breezy/windy and wet forecast in in store for the next 24 hour
period of the general area as a prefrontal trough is replaced by a
warm front moving across the area on Monday. Some minor impacts
to visibility in locally stronger rain rates are possible
(4-5sm), however the lower end of the categorical risk is not
anticipated as ceilings remain largely above the MVFR level in
rain. Strong southwest winds are likely (80-90%) to gust higher
than 22 knots and 35 knots is the cutoff, where much lower odds of
winds that strong will be at BDN/RDM, but still more likely
(65-85% confidence) across terminals like DLS/PSC/ALW/PDT late in
the TAF period. Russell/71
&&
.PREV DISCUSSION... /issued 239 PM PST Sun Dec 7 2025/
DISCUSSION...Rest of Today: Light rain in the lower elevations
has tapered off this afternoon as rain/high elevation snow showers
have started to develop along the Cascade crest and portions of
the northern Blues. Showers will continue tonight as a quick
moving cold front and shortwave slides across the PacNW. Breezy
southwest winds will continue overnight behind the cold front
passage, but confidence is low (<20%) in wind gusts 45mph or
higher developing.
Monday through Thursday: Ensemble and deterministic guidance is in
good agreement that multiple surface frontal and upper shortwaves
will slide down the west side of an upper ridge of high pressure
in the northeast Pacific through the midweek, with each of these
systems sliding across the PacNW each day. These systems will also
be accompanied by a persistent plume of tropical to subtropical
moisture that will see IVT values of 500 to 750 kg/m/s, resulting
in high confidence of heavy rain developing across most mountain
zones through this period, while a cold front passage Monday night
into Tuesday will result in the best chance of moderate to locally
heavy rain in the lower elevations (confidence 70-85%). Due to
the warmer nature of the incoming AR, snow levels will mainly be
above 5.5kft throughout the AR duration, however a cold front
passage Monday night into Tuesday will briefly bring snow levels
down to pass level in the central WA Cascades with wet snow
developing in White, Snoqualmie, and Blewett passes. Otherwise, a
low level jet (50-70kts) will move over the PacNW by Monday
afternoon, with strong winds mixing down into Columbia Basin/Gorge
and adjacent valleys/foothills through Tuesday morning as the
cold front moves across the forecast area. Confidence is
moderate- high(70-85%) that sustained winds of 25-35mph with gusts
45-55mph will impact wind prone areas, with stronger gusts across
exposed ridges in the Columbia Plateau and along the Cascade
crest and east slopes.
Over a 3 day period ending Thursday morning (covering the peak of
the AR), the NBM shows the WA Cascade crest at a 50-70% chance for
at least 7 inches of QPF, while the Cascade crest overall will
see a 50-85% chance of receiving 5 inches or more of QPF, and the
northern Blue Mountains will see a 35-50% chance of at least 3
inches in the same period. Area rivers and streams will rise
beginning early this week as most of the incoming precipitation in
the mountains is expected to fall as rain (confidence 65-85%). Of
note, rivers originating from the WA Cascade east slopes will see
rises into at least action stage Monday night into Tuesday
morning (confidence 60-80%), with low confidence (10-25%) in
rivers reaching minor flood stages at this time.
By late Thursday, there remains good agreement that the upper
ridge offshore will amplify and nudge closer to the PacNW,
effectively moving the AR north of the region. Precip chances and
amounts will gradually wane from south to north throughout the
day, with dry conditions returning to the lower elevations by
Thursday night (confidence 55-75%).
Friday into the Weekend: Good agreement remains amongst ensemble
guidance that the upper ridge will remain amplified as the ridge
axis approaches the PacNW Friday and moves inland Saturday. This
will result in precipitation chances mainly across the WA Cascade
crest through this period, with dry conditions elsewhere. That
said, about 12% of ensemble cluster members (ECMWF, GFS, and
Canadian) do favor the ridge being less amplified as it moves
inland Saturday, resulting in light rain and high mountain snow
across the Cascade crest into Oregon and across the Blue
Mountains. Lawhorn/82
AVIATION...00Z TAFS...VFR conditions currently across all sites,
but conditions are expected to degrade to MVFR for KDLS toward the
end of the period due to reduced visibilities of 4SM and ceilings of
1kft. Light rain will be impacting all sites Monday morning, with
breezy winds anticipated for KPDT/KRDM/KBDN/KALW. Gusts at these
sites are likely to hover around 25 kts late Monday morning as a
cold front passes the area. 75
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 42 59 47 56 / 40 70 70 90
ALW 45 57 48 54 / 50 90 80 90
PSC 43 60 48 56 / 10 60 50 70
YKM 36 55 40 51 / 10 80 70 70
HRI 42 62 49 57 / 20 60 60 90
ELN 33 49 37 46 / 20 90 80 60
RDM 36 57 44 57 / 30 40 40 80
LGD 37 49 44 51 / 70 80 90 100
GCD 37 52 45 51 / 40 50 50 90
DLS 46 59 50 55 / 60 90 90 90
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Wind Advisory from 1 PM Monday to 7 AM PST Tuesday for ORZ041-
510.
Wind Advisory from 4 PM Monday to 7 AM PST Tuesday for ORZ044-
507-508.
WA...Wind Advisory from 1 PM Monday to 7 AM PST Tuesday for WAZ024-
521.
Wind Advisory from 7 PM Monday to 7 AM PST Tuesday for
WAZ027>029.
&&
$$
SHORT TERM...99
LONG TERM....99
AVIATION...71
