671 
FXUS66 KPQR 150452 AAA
AFDPQR

Area Forecast Discussion...UPDATED
National Weather Service Portland OR
952 PM PDT Tue Oct 14 2025

Updated aviation and marine discussions. 

.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.

&&

.SHORT TERM...Now through Friday 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.
														-36



.LONG TERM...Saturday through Tuesday...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...Clear and dry for the next 24 hours with easterly
becoming northerly winds. Minimal impacts. Cooler temperatures 
overnight will increase chances for frost to form within the 
interior valleys. This will impact Willamette Valley terminals 
from KUAO southward. Freezing temperatures expected around K4S2. 
Easterly gusty winds will dissipate overnight, increasing once 
again in the afternoon after 18Z Wed though winds will take on a 
bit more of a southeasterly direction. While southeast winds will 
generally be strongest around KKLS and KSPB, terminals through 
Columbia River Gorge and greater Portland-Vancouver Metro area 
including KHIO may receive slightly elevated winds.

Late in the forecast winds will ease along the coast becoming
weakly southerly. There is the hint for the potential for fog or
lower stratus around KONP, however confidence is low at this 
time.

KPDX AND APPROACHES...VFR through the next 24 hours. Light winds
at the surface overnight from the northeast, with easterly flow
aloft above 2000 ft AGL. Until 09Z Wed, gusts up to 30 kt possible
between 1500-3000 ft AGL. While speed shear is present, with a
lack of directional shear have omitted from the TAF. However,
these wind speeds may become impactful for flow into the terminal. 
														-27


&&

.MARINE...High pressure over the area has kept the waters under
marginal Small Craft Advisory criteria. In general, winds have
eased below 21 kt, though there have been isolated gusts around
buoy 46029 this evening. Overall though, conditions have been
right along the threshold and are expected to fall below criteria. 

With the high pressure in place, northerly winds will persist
with enhanced wind waves through Thursday morning. Seas will
remain around 5-7 ft at 15 seconds with winds around 10 kt. The
next period of concern arises on Friday with the onset of a weak
frontal passage. Will see a quick surge of a northwesterly fresh
swell and elevated winds. There is nearly an 80% chance based on
the GEFS WAVE models of seas of 10 ft or more late Friday into
Saturday. Conditions will quickly amplify with a 20-40% chance of
seas greater than 15 ft late Sunday.					-27

&&

.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 PDT tonight for PZZ272-273.
&&

$$

www.weather.gov/portland

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