652
FXUS66 KPQR 090545
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
945 PM PST Sat Nov 8 2025

Updated Aviation Discussion and Watch/Warning/Advisories...

&&

.SYNOPSIS...Dry weather this weekend as high pressure builds
over the region. Offshore flow will also increase, with breezy
easterly winds through the Columbia River Gorge and eastern
Portland/Vancouver Metro. A weak shortwave trough will bring a
chance for light rain across the forecast area starting late
Sunday night/early Monday morning. Light precipitation will
continue to spread across the CWA through Monday. Relatively dry
conditions for Tuesday, with widespread precipitation and with
cooler temperatures starting Wednesday and expected to persist
through the end of next week.

&&

.DISCUSSION...Today through Saturday...An upper level ridge
will continue to build over the Pacific Northwest through the
weekend and result in drier conditions across the CWA. As the
upper level ridge builds over the area, a thermally induced
surface trough also develops will result in easterly winds
through the Columbia River Gorge and eastern Portland/Vancouver
Metro Area. Latest guidance from the GFS, NAM and SREF have the
KPDX to DLS pressure gradient peaking around -6 to -8 mb
Saturday night into early Sunday morning. Given that easterly
winds have been slightly stronger and earlier than initial
guidance had suggested, the peak still looks to be overnight,
but might last longer and be slightly stronger. At this time,
expect wind gusts up to 45 mph for the far eastern
Portland/Vancouver Metro area (Troutdale/Camas), and up to 60
mph for exposed ridgetops (Crown Point and Three Corner Rock).
Sunday is shaping up to be slightly warmer than today as the
upper level ridge amplifies and shifts eastward over the Great
Basin.

Sunday night into Monday, the upper ridge begins to flatten as a
shortwave trough pushes into British Columbia and NW Washington.
Guidance is showing that the front associated with this upper
level shortwave will either track northward, be relatively weak
or both. The result is a moderate to high PoP/low QPF scenario.
Currently, the highest chances for rain are along the coast and
southwest Washington (50-80%), while chances for rain are lower
(20-40%) across interior northwest Oregon. Precipitation will
likely arrive at the coast late Sunday evening/Sunday night and
slowly push inland through Monday morning. Total precipitation
with this shortwave for the coast and SW Washington range from
0.01-0.10 inches and for NW Oregon range from a Trace to 0.05
inches over a 24-36 hour period.

Tuesday, another shortwave upper level ridge builds over the
Pacific Northwest and this will bring a brief return of dry
weather. However, by Wednesday, this ridge quickly gets pushed
eastward as a more robust low in the NE Pacific takes aim at the
Pac NW. This more robust system will bring rain and cooler air
back into the forecast. Current guidance has precipitation
starting Wednesday morning. Precipitation will remain in the
forecast through at least the end of the week. Thursday will
also introduce cooler air into the forecast. 850 mb
temperatures fall towards -1 to -3 C, which would also bring
snow into the forecast for higher elevations within the
Cascades. It is still well into the future for accurate snow
accumulations for the Cascades, but we will continue to monitor
and update the forecast. /42

&&

.AVIATION...High pressure inland continues to support offshore
flow and largely VFR conditions across the region. Gusts of 20-30
kt reach west of the Columbia Gorge to KPDX/KTTD and through other
east-west oriented terrain gaps, but will trend downward late
Saturday night through Sunday morning as the pressure gradient
begins to weaken. These east winds will inhibit any fog formation
at both Portland-area terminals as well as along the coast. Cigs
begin to trend downward late in the period as a weak frontal
system approaches the coast, with a 30% light rain showers reach
KAST by 03-06z Mon.

Along the Willamette Valley, as well as other sheltered valleys in
the Coast Range and Cascades, light north to northeasterly winds
will support another night of valley fog/mist or low stratus.
Confidence in fog development is the highest east of I-5 in the
southern and central Willamette Valley, most notably including
KEUG where there is a 50-70% chance in IFR vis/cigs within fog as
soon as 08-10z Sun. Chances for IFR conditions are lower to the
north including at KSLE/KUAO/KHIO, some 20-40%, with periods of
MVFR vis in mist more likely. If northerly winds remain higher, a
low stratus deck may be favored instead of surface-based fog. Any
restricted vis should clear by 17-20z Sun.

KPDX AND APPROACHES...VFR conditions expected through the TAF
period. East winds of 15 kt with gusts to 25 kt will continue
tonight, before easing to around 10 kt after 12-15z Sun. -36

&&

.MARINE...High pressure building inland will drive offshore
(easterly) winds around 10-15 kt today. Some gusts up to 20-25
kts are possible in stronger gap-flow winds due to offshore
flow, though they are not widespread enough for a Small Craft
Advisory. Winds turn south to southeast on Sunday as a weak
front approaches the waters, decreasing as gap-flow winds end.
Seas of 6-9 ft at 10-12 seconds this evening will generally
remain this way through Sunday. However, another strong ebb
Sunday evening will yield seas of 9-10 ft in the Columbia River
Bar, where a Small Craft Advisory is in effect from 4-10 PM.

Wind direction varies through the first half of next week, but
wind speeds look to remain at 5-10 kt through Wednesday morning.
There is also high confidence (greater than 95% chance) that seas
remain below 10 ft through midweek as well. An area of low
pressure strengthening well offshore will see increasing southerly
winds and a building southerly swell, increasing the chances for
another period of conditions hazardous to small craft late
Wednesday into Thursday. At this point, gale-force winds are not
favored during this period, with 30-50% chances of occurrence
beyond 20-30NM.

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.

WA...None.

PZ...Small Craft Advisory from 4 PM to 10 PM PST Sunday for PZZ210.

&&

$$

www.weather.gov/portland

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