152
FXUS66 KPQR 142140
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
240 PM PDT Tue Oct 14 2025

.SYNOPSIS...An upper-level ridge will yield another cold night
tonight with areas of frost within some sheltered valleys, and
continued clear and dry weather through much of Wednesday. A
weak system may bring light showers Thursday into Friday, before
more widespread rain is likely this weekend as a trough digs
over the Northeast Pacific.

&&

.DISCUSSION...Now through Monday Night...A positively-tilted
upper-level shortwave ridge axis currently extending across
Vancouver Island into interior western Canada will continue to
slide eastward, passing overhead and deamplifying through
Thursday. Meanwhile, weak surface troughing along the coast will
support offshore easterly to northeasterly flow and persistent
clear skies with dry weather. As diurnal winds ease tonight,
these ideal conditions for efficient radiative cooling will see
temperatures fall to overnight lows largely in the 30s to low
40s. The warmest lows in the low to mid 40s are expected along
the coast, where the Pacific will moderate temperatures, and
through the Columbia River Gorge, where a continued easterly
breeze will stymie surface cooling.

The coldest locale is likely to be the Upper Hood River Valley,
where a Freeze Warning is now in effect from 1 AM through 9 AM
PDT Wednesday. Areas including Odell and Parkdale have a 65-85%
chance seeing temperatures at or below freezing, and a 30-60%
chance of falling into the upper 20s by sunrise. In both cases,
those chances are higher farther up the valley and lower toward
Hood River proper. Other places the most likely to fall into
the low to mid 30s and see areas of frost are the Cowlitz/Lewis
River Valleys, the central and southern Willamette Valley, and
wind-sheltered locales in the northern Oregon Coast Range,
especially the Nehalem Valley including Vernonia and Pittsburg.
Frost Advisories have also been issued for these areas from 1
AM to 9 AM PDT Wednesday; those with agricultural interests or
other outdoor plants which may be harmed by cold temperatures
should take preventative measures.

More seasonable onshore northwesterly flow returns Wednesday
afternoon with increased cloud cover. A weak trough and frontal
system passing well to the north may yield a few rain showers
early Thursday through Friday morning, most likely along the
coast and across the higher terrain of the Coast Range, Willapa
Hills, and Cascades. The immediate shorelines of Willapa Bay,
Long Beach Peninsula, and coastal Clatsop County, as well as
upstream in the Columbia Estuary to Cathlamet/Wauna, may see a
25-50% chance of 0.25" of rain or more, while chances of a
wetting rain elsewhere and inland are generally 15% or less.

Toward the weekend, there is good consensus that a trough will
dig over the Northeastern Pacific, bringing a return to wetter
weather across the Pacific Northwest. At this lead time, there
is high confidence in the occurrence of rain while the main
mode of uncertainty is the amplitude of the trough. Around 45%
of global ensemble members favor a deeper trough and a resultant
wetter outcome, while another 30% favor a weaker trough and a
drier scenario. There is also some uncertainty around how
progressive the pattern is, and therefore the timing of
precipitation onset. There is also a high likelihood in below
normal temperatures from Sunday into early next week as the
upper trough moves overhead. -36

&&

.AVIATION...An upper level ridge just offshore will maintain
northeasterly winds aloft through tonight. VFR conditions with
mostly clear skies persists as high pressure builds over the
region. Offshore east to northeast winds remain gusty through
this afternoon with gusts up to 20-25 kt. Winds expected to
ease later this evening.

KPDX AND APPROACHES...VFR with mostly clear skies through the
TAF period. East winds with gusts up to 25 kt expected through
02-03z this evening. /02

&&

.MARINE...High pressure remains offshore while an inverted
trough of surface low pressure along the Oregon coast
maintains breezy north to northeast winds, before weakening
overnight. Strongest winds expected across the outer coastal
waters south of Cape Falcon with gusts up to 25 kt through this
evening. Winds ease as pressure gradients decrease across the
coastal water through Wednesday, becoming northwesterly around
10 kt or less. Relatively tranquil conditions continue into
Thursday, with light onshore winds and seas lingering around 4
to 6 ft.

A weak front will approach the waters late Thursday into Friday,
followed by the return of high pressure, with minimal concerns.
A longer period northwest swell arrives later Friday, building
seas to around 10 ft late Friday night into Saturday morning. A
stronger frontal system is very likely to bring increasing
southerly winds and higher seas during the weekend. Uncertainty
remains with timing and strength of the system, but guidance
does suggest there is around a 40-50% chance of gale force winds
gusts late Saturday, especially across the northern inner
waters. This front will likely be followed by a westerly swell
building seas into the lower to mid teens on Sunday, with a 10%
chance of significant wave heights exceeding 20 ft. /02

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...Frost Advisory from 1 AM to 9 AM PDT Wednesday for ORZ104-
     115>118.

     Freeze Warning from 1 AM to 9 AM PDT Wednesday for ORZ121.

WA...Frost Advisory from 1 AM to 9 AM PDT Wednesday for WAZ204.

PZ...Small Craft Advisory until midnight tonight for PZZ272-273.

&&

$$

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