838
FXUS66 KPQR 131032
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
332 AM PDT Mon Oct 13 2025

.SYNOPSIS...
A cool and unsettled pattern continues across the Pacific
Northwest through today as a broad upper-level trough, with its
center low currently over the region, maintains a slow southeastward
progression. Showers and mountain snow will continue this
morning before tapering off later today as the system exits.
Temperatures will remain below seasonal averages through
tonight. A ridge of high pressure then builds overhead beginning
Tuesday, ushering in a warmer and drier trend through midweek.
Model guidance diverges toward the end of the week regarding
the potential return of a coastal low and increasing cloud
cover.

&&

.DISCUSSION...Now through Saturday...Showers continue early this
morning across parts of northwest Oregon and southwest
Washington, with locally heavier bursts near the Cascade
foothills. The center of the low is currently positioned over
the region, supporting ongoing precipitation. Satellite and
radar imagery show scattered showers, which are expected to
gradually diminish through the day as the trough continues
southeastward.

Colder air aloft has lowered snow levels to around 4000 to 5000
feet, producing accumulating snow across the Cascades. A Winter
Weather Advisory remains in effect for elevations above 4000
feet through this morning. Cascade passes will likely see 1 to
2 inches more of wet snow through the morning, while Highway 26
near Government Camp may see an additional trace to half of an
inch. Above 5000 feet for areas north of The Three Sisters,
expect an additional 3 to 7 inches through this morning, which
could still impact travel on unmaintained roads.

As the trough moves southeast later today, skies will gradually
clear, setting the stage for colder overnight temperatures. In
the Upper Hood River Valley, a Frost Advisory remains in effect
until 9 AM this morning due to reduced cloud cover and efficient
radiational cooling. For tonight, a Freeze Warning is in effect
from 12 AM to 9 AM Tuesday for the same area, where temperatures
are expected to fall below freezing. The probability of
temperatures at or below 32 degrees ranges from 50 to 90
percent, while the probability of 28 degrees or colder ranges
from 5 to 35 percent, highest to lowest from Parkdale to Odell.
Sensitive vegetation and unprotected plumbing may be affected.

In addition, Frost Advisories have been issued for tonight from
12 AM to 9 AM Tuesday across several other locations expected
to experience similar cooling under clearing skies. These
include the Lane County Cascade Foothills, Lane County Lowlands,
Linn County Lowlands, North Oregon Coast Range Lowlands, South
Washington Cascade Foothills, and Cowlitz County Lowlands. These
areas are likely to see patchy frost and near-freezing
temperatures capable of damaging unprotected plants and crops.
With easterly winds in the forecast, there is some uncertainty
on which locations may or may not cool toward these forecasted
temperatures.

From Tuesday through Thursday, ensemble and deterministic
guidance supports a broad ridge over the Pacific Northwest,
bringing warmer and drier weather. Highs will moderate into the
mid to upper 60s across the lowlands, coast, and Coast Range,
with upper 40s to upper 50s across the Cascades. Toward Thursday
and into the weekend, forecast confidence decreases as model
solutions diverge. Some guidance indicates a shortwave trough
may approach the coast late in the week, which could result in
increasing cloud cover and light precipitation returning to
parts of the region.
~12

&&

.AVIATION...Scattered rain showers continue over much of northwest
Oregon and parts of southwest Washington, with a mix of CIGs from
low- end VFR to low-end MVFR. Showers will continue through this
morning, expected to taper off by 17-19Z Monday. As showers
persist during the aforementioned timeframe, expect a mix of
VFR/MVFR conditions to continue, with guidance suggesting a 30-50%
chance of MVFR conditions until 18-19Z Monday (highest chances to
the south).

By Monday afternoon, expect offshore flow to develop and bring
clearing skies and VFR conditions throughout the airspace.
Additionally, this offshore flow will bring breezy east to
northeast winds with gusts up to 20-25 kt for all TAF sites.

KPDX AND APPROACHES...Expect a mix of MVFR/VFR CIGs until 18-19Z
Monday (20-30% chance for MVFR CIGs). VFR conditions after 18-19Z
Monday as offshore flow develops. This flow will bring clearing
skies and breezy east winds with gusts up to 20-25 kt.
~12

&&

.MARINE...A low pressure systems currently located over the region
continues to slowly move southward. This will bring gusty north
to northeasterly winds through today for most of the waters. Small
Craft Advisory conditions are expected to persist until 11 PM
Monday for the central and southern waters, and until 5 PM for the
northern waters. As the low moves southward through today, seas
currently around 8-10 ft will decrease. An offshore pressure
gradient will maintain northeasterly winds into Tuesday, shifting
back to onshore flow late Tuesday. Seas will drop to 5-7 ft at
8-10 seconds Tuesday.

While the weather pattern remains a bit uncertain for this
upcoming weekend, model guidance for wave height has improved. On
Saturday, there is moderate to high confidence for seas around 8
to 10 ft. Greater uncertainty remains for Sunday, with an 80%
chance for seas between 9 and 15 ft.
~12

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...Frost Advisory from midnight tonight to 9 AM PDT Tuesday for
     ORZ104-117-118-125.

     Frost Advisory until 9 AM PDT this morning for ORZ121.

     Freeze Warning from midnight tonight to 9 AM PDT Tuesday for
     ORZ121.

     Winter Weather Advisory until 11 AM PDT this morning for
     ORZ126>128.

WA...Frost Advisory from midnight tonight to 9 AM PDT Tuesday for
     WAZ204-208.

     Winter Weather Advisory until 11 AM PDT this morning for WAZ211.

PZ...Small Craft Advisory until 5 PM PDT this afternoon for PZZ251-
     271.

     Small Craft Advisory until 11 PM PDT this evening for PZZ252-253-
     272-273.
&&

$$

www.weather.gov/portland

Interact with us via social media:
www.facebook.com/NWSPortland
x.com/NWSPortland