121
FXUS66 KPQR 022322 AAA
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
321 PM PST Sun Nov 2 2025

.SYNOPSIS...The next round of rain moves into the region beginning
Monday morning as a compact surface low develops offshore and moves
through western Oregon. Trending drier on Tuesday aside from a few
spotty light showers. The weather pattern becomes much more active
Tuesday night through Friday morning as a strong low pressure system
develops offshore and sends a series of fronts into western WA/OR.
Expect widespread rain and gusty winds with each frontal passage,
with the heaviest period of rain expected Thursday and Thursday
night. This is also when the strongest winds are expected with max
wind gusts likely peaking between at least 30-40 mph inland and 50-55
mph at the coast. In addition, coastal flooding is expected along
portions of Highway 101 and Fraser Road in Tillamook County around
high tide on Wednesday from 10 AM to 2 PM PST, with water up to one
foot above ground level.

&&

.SHORT TERM...Now through Tuesday...Satellite and surface weather
observations from Sunday afternoon depicted mostly clear skies across
southwest WA and northwest OR, aside from southwest WA and far
northwest OR where high clouds were beginning to increase. Cloud
cover will increase over the entire area Sunday night into Monday
morning as a compact mesolow over the coastal waters moves
northeastward towards the central Oregon coast. An area of light to
moderate stratiform rain will accompany this low, spreading over the
area between 3-9am Monday. Rain will then persist through the day on
Monday before transitioning to off and on light rain showers Monday
night. Rain should be heaviest Monday afternoon and evening with most
locations picking up at least 0.5 inches of rain (50-80% chance for
0.5 inches or more, with the highest probabilities in the mountains
and at the coast).

Fortunately, hi-res model guidance suggest hourly rain rates will
stay under 0.20-0.25 in/hr, suggesting urban flooding will not be a
concern. There are no concerns for river flooding with this system
either. Lastly, a brief period of gusty south winds with peak wind
gusts up to 30-45 mph are likely along the central Oregon coast to
the south of Pacific City Monday evening as the mesolow moves inland.
The strongest wind gusts will occur along beaches and headlands. Come
Tuesday, an upper level shortwave ridge will bring and end to
precipitation aside from a few spotty light rain showers lingering.
Winds will be lighter by then with mostly cloudy skies.  -23


.LONG TERM...Tuesday night through Saturday night...The long term
forecast is highlighted by an active weather pattern with periods of
wet and windy conditions, especially Tuesday night through Thursday
night. This is when models and their ensembles show good agreement
for a strong low pressure system offshore near the Gulf of Alaska.
Although the center of this low pressure system is not expected to
make landfall in southwest WA or western OR, a series of strong
frontal passages associated with this low will move inland, with each
front bringing gusty southerly winds and widespread rain to the
region. The first front will arrive Tuesday night, bringing mainly
light to moderate rain with wind gusts up to 25-35 mph inland and up
to 40-45 mph at the coast.

However, rain will become heavier on Wednesday while winds likely
increase with gusts up to at least 30-40 mph inland and up to 50-55
mph at the coast. This would be strong enough to result in some tree
damage and power outages, but would not be strong enough for
widespread downed trees and significant impacts. That said, there is
still some uncertainty regarding exact wind speeds, as some model
ensemble guidance shows higher winds. The NBM currently suggests a
5-20% chance for max wind gusts over 45 mph inland, and a 20-40%
chance for max wind gusts over 55 mph along and near coast (mainly
for beaches and headlands and exposed ridges in the Coast Range). If
wind gusts of this magnitude materialize, wind headlines would be
needed as impacts such as downed trees and power outages would become
more widespread. While this is not the most likely outcome at this
time, the forecast is worth monitoring over the next couple of days
for potential changes.

Yet another frontal system is set to arrive Thursday, bringing a
renewed round of rain and gusty southerly winds. Wind speeds with
this front look to be fairly similar to Wednesday, except at the
coast and higher elevations in the Coast Range where probabilities
for max wind gusts over 55 mph are relatively higher (35-60% chance).
This frontal system is also on track to produce the heaviest rain of
any of the frontal systems impacting the area this week. WPC QPF
amounts from 4am Thursday through 4am Friday range between 1-1.25
inches for inland valleys, 1.5-2.0 inches for the coast and Cascade
foothills, and 2-3 inches for the Coast Range and south WA/north OR
Cascades. Given all the rain that is forecast to fall prior to the
system on Thursday, rising river levels will be a concern. The main
question that remains is whether or not enough rain will fall for
some rivers to reach flood stage on Wednesday and/or Thursday.
According to the latest HEFS guidance, the probability for any given
river to reach minor flood stage is generally 10% or less, except a
25% chance for the Wilson River near Tillamook. Another river of
concern would be the Grays River near Rosburg. Small creeks and
streams are more likely to see some minor flooding. Lastly, minor
urban flooding will also be possible, especially in low-lying areas
with poor drainage. Rain chances remain in the forecast Friday
through Saturday night, however ensemble guidance suggests rain
amounts will be lighter and less impactful. Winds will also be weaker
by then.  -23

&&

.AVIATION...Expect mostly clear skies through the TAF period, with
rain tomorrow morning for all terminals. Specifically, expect rain
to begin along the coast around 15-17Z Monday and inland around
17-19Z Monday. While VFR conditions will persist most of the
period, this rain will likely bring MVFR conditions to the region
around 18-20Z Monday (40-60% chance for MVFR conditions).

Southern and central Willamette Valley terminals may experience
deteriorated conditions around 04-08Z Monday if fog/stratus is to
form again overnight. Current guidance suggests a 10-30% chance
for IFR/LIFR conditions for KSLE and southward. Winds will be out
of the north through most of the day, then shift more northeasterly
to easterly overnight. Expect winds to remain between 5-10 kt
during the evening, with a few terminals (KEUG, KTTD) potentially
seeing gusts up to 20 kt.

KPDX AND APPROACHES...Expect VFR conditions through most of the
TAF period, with a 40-60% chance for MVFR CIGs around 18Z Monday.
Expect northerly winds around 4-8 kt through the day, then
easterly 5-10 kt by 9-12Z Monday.  ~12

&&

.MARINE...Brief high pressure passes overhead today into Monday.
Winds will turn north to northeast and increase as a thermal
trough forms over the coast through tonight. Seas are expected to
remain around 11-13 ft at 13-14 seconds through much of the
period. A Small Craft Advisory remains in effect until 4 PM PST
Monday. Additionally, with a low pressure system potentially
moving through our southern waters on Monday and bringing a 50-60%
chance for wind gusts over 34 kt, a Gale Watch has been issued
from 4 PM Monday to 1 AM Tuesday for the inner and outer waters
from Cape Foulweather to Florence OR.

An active pattern will return during the middle of this week as a
couple of frontal systems bring strong Gales or even Storm force
winds, along with elevated seas. Looking at 24 hour probabilities
for wind gusts, there is an 80 to 90% chance for Gale Force winds
(gusts > 34 kt) in the far outer waters on Tuesday then spreading
over all of the coastal waters for Wednesday and Thursday. The
probability for Storm Force winds (gusts > 48 kt) is around 25-50%
chance each day Tuesday through Thursday. Note that higher
probabilities will stay elevated along the inner waters during
the duration of these weather systems. Seas are also expected to
increase, with mainly wind driven seas pushing into the mid to
upper teens by Wednesday and lasting into Thursday. Guidance
currently suggests a 5-10% chance that seas will exceed 20 ft.
There is still plenty of uncertainty in exact details but the
active pattern is expected to persist.~12/03

&&

.BEACH HAZARDS...A westerly swell of 11-14 ft at 14-15 seconds
will bring a high threat of sneaker waves through Monday along the
North and Central Oregon Coast, and the South Washington Coast.
Caution should be used when in or near the water. Always keep an
eye on the waves, and be especially watchful of children and pets.
Those participating in razor clam digs should exercise caution.

Additionally, there is a Coastal Flood Advisory for minor tidal
overflow flooding during high tide from 10 AM to 2 PM Wednesday
for the South Washington Coast, Clatsop County Coast, and
Tillamook County Coast. Minor flooding, up to 1 foot above ground
level, during high tides is expected in the low lying areas near
bays, sloughs, and the lower reaches of the coastal rivers. Expect
flooding along portions of Highway 101, including near Raymond,
Seaside, and Fraser Road in Tillamook County. Coastal residents
in the warned area should be alert for rising water, and take
appropriate action to protect life and property. Remain out of
flood waters to avoid hazardous swimming conditions, and never drive
on flooded roads.

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...Coastal Flood Advisory from 10 AM to 2 PM PST Wednesday for
     ORZ101-102.

WA...Coastal Flood Advisory from 10 AM to 2 PM PST Wednesday for
     WAZ201.

PZ...Small Craft Advisory until 4 PM PST Monday for PZZ210-251>253-
     271>273.

     Gale Watch from Monday afternoon through late Monday night for
     PZZ253-273.
&&

$$

www.weather.gov/portland

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