290
FXUS66 KPQR 272155
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
155 PM PST Thu Nov 27 2025

.SYNOPSIS...Low pressure sits just offshore which will be the
main weather maker through Friday. Gusty southerly winds along
the coast and within the Willamette Valley are amplifying, with
easterly winds through the Columbia River Gorge. Another round
of rain will arrive overnight with continued breezy winds.
Trending drier through the weekend with weak shortwaves embedded
in the flow. Cool down remains on Monday with lows dipping into
the mid 30s Monday morning. Rain returns mid-week.


&&

.SHORT TERM...Now through Sunday...Satellite imagery shows an
area of low pressure near 46.6N, -128.4W clocking in around 1006
mb, and continues to fall as it nears the shore. As it shifts
eastward, southerly winds will amplify as the pressure gradient
narrows. The winds will be strongest along the coast and within
the Willamette Valley. For inland sites, there is around a
50-70% chance of gusts greater than 35 mph this evening with the
highest wind speeds around Portland. Easterly winds have
lingered quite a bit longer than previously though within the
Columbia River Gorge with gusts up to 35 mph reported around
Troutdale. Based on the pressure gradient forecast alone, gusty
winds will prevail for the next 12 hours at least. Due to rain,
and leaves still on trees, cannot rule out downed branches
within the Greater Portland-Vancouver Metro and areas north of
Salem. Along the coast there is a 50-70% chance of gusts up to
40 mph with highest wind speeds south of Tillamook.

The occluded front from the morning has moved well inland and a
warm front is quickly tailing. This warm front will bring
another round of rain this evening. Highest probability and
accumulations will be after midnight through the morning commute
inland. The coast, Cascades, and areas north of Salem will see
the highest precipitation amounts. For our skiers,
unfortunately snow levels remain quite high - greater than 5500
ft. The southern portions of the forecast area will see less
rain due to the tilt of the front and the moisture influx. There
will still be observed rain though.

Through the weekend a ridge will build in with a closed low
forming well to the south. This ridge will keep conditions
drier than normal. Looking at the upper level pattern though
there is a weak disturbance at 500 mb that is associated with a
short wave. May see a burst of rain late Saturday into early
Sunday morning. Deterministic pressure forecast shows a
compressing gradient. There is quite a bit of variation between
the models, but the most intense gradient is around -6 mb
between Troutdale and the Dalles. This could insinuate another
round of elevated winds through the Columbia River Gorge and
around Troutdale. The NBM 24-hr maximum gust model outputs show
the mean around 43 mph with a 10% chance of gusts as high as 60
mph. This would mainly be in the south Washington Cascade
foothills near Three Corner Rock and Larch Mountain. -27


.LONG TERM...Sunday Night through Thursday...The high pressure
ridge remains in place with relatively high confidence given the
distance into the future. Nearly all 500 mb ensembles show this
ridge being in place. Therefore, we continue to come into better
agreement on the Sunday night into Monday forecast. With the
ridging skies will clear. The clearing skies, especially
overnight into Monday morning, in combination with cooler air
filtering in from the east will cause overnight lows to drop.
These lows have the potential to be the coolest observed thus
far this year. In Eugene for example, the 25th to 75th
percentile (most likely range) shows a spread of 26-32 degrees
F, while there is a 10% chance of 24 degrees F. The thing to
remember is that these are the minimum temperature for the night
and may only be one instantaneous observation. There is a
higher probability that that temperatures will be above freezing
for most of the night into Monday morning. With that said,
light winds, clear skies, and these temperatures will lead to
widespread frost.

Another warm frontal system moves in on Tuesday with even more
stratiform rain. At this time, no major impacts expected as snow
levels will be above pass level. The 10th percentile snow level
(the lower elevation snow levels that would occur if the colder
solutions manifest) is still above 3000 ft. So even if the warm
frontal system loses some momentum, snow is not in the forecast
for quite a while. Light rain persists through mid-week with
minimal change in the overall forecast. -27


&&

.AVIATION...Shallow, light rain showers continue behind the
departing frontal boundary. Largely MVFR cigs with unrestricted
vis are favored through the mid-afternoon. Intermittent rain
showers may briefly yield MVFR/high-end IFR vis if showers move
over area terminals, however precise timing of these potential
impacts is low confidence. Otherwise, increasing southerly winds
are expected across the region as an area of low pressure nears
the coast, reaching around 20 kt with gusts to 30-35 kt along the
coast and 15 kt with gusts to 25-30 kt inland into this evening.
One exception to this will be west of the Columbia River Gorge,
where offshore flow will continue until the low moves onshore,
yielding continued gusty east winds at KTTD through 00z Fri. These
easterly or southeasterly gusts will also reach to KPDX, however
the flow will ultimately turn out of the south by midday.

As steadier rain arrives by 21-24z Thu, a period of marginal VFR
cigs may be expected inland, however there will remain a 40-50%
chance cigs remain below 3 kft. Vis restrictions to MVFR levels
within light rain are most likely along the coast, 40-60% chances,
and less so inland, 20-40% chances, through the evening and into
tonight as cigs trend back down to MVFR levels at 1-2 kft.
Widespread IFR cigs late in the period remain relatively unlikely,
less than 20% chances across the region. Behind this additional
frontal boundary, wind gusts will weaken below 20 kt as winds turn
out of the southwest to west after 06-12z Fri.

KPDX AND APPROACHES...Largely MVFR conditions expected to continue
into this afternoon, however brief periods of IFR vis within
intermittent rain showers remains possible. After 22-24z Thu,
steadier rainfall may aid in lifting cigs above 3 kft, but there
is a 40% chance conditions instead remain MVFR. Chances for
further MVFR cigs increase late in the period, after 06-09z Fri.
Initial easterly/southeasterly winds will turn out of the south by
20-22z Thu, and increase to around 15 kt with gusts of 25-30 kt.
These gusts are expected to continue through at least 06z Fri
before easing behind the frontal boundary. -36

&&

.MARINE...An area of surface low pressure visible on satellite
imagery about 100 miles west of the mouth of the Columbia River
early this afternoon will continue to weaken as it nears the coast
this evening. Despite the weakening trend, a tight pressure
gradient over the waters will support persistent gusty winds.
Regional buoys have thus far observed south winds around 25 kt
with gusts near 35 kt, conditions which will continue to degrade
as sustained winds further rise through this afternoon to near 30
kt with gusts of 35-40 kt as the low tracks toward the south
Washington coast, before easing as winds veer out of the west and
ultimately out of the northwest behind the low through tonight.
Meanwhile, buoys are additionally observing 10-12 ft seas across
the inner waters, while 14-16 ft seas in the outer waters are
expected to increase to 15-19 ft across the waters this evening.
There is still a 15-20% chances seas exceed 20 ft beyond 30 NM and
south of Cape Falcon, and lesser chances elsewhere. Conditions
will improve through tonight as seas fall below 10 ft and winds
below 10 kt by Friday afternoon.

These conditions support Gale Warnings in place across the waters
through this evening, specifically through 8 PM beyond 10 NM and
across the Columbia River Bar, and through 10 PM across the inner
waters where coastal wind enhancements may maintain elevated winds
a few hours later. Hazardous Seas Warnings will then be in effect
across all coastal waters through 2 AM early Friday morning, then
Small Craft Advisories from 2 AM through 11 AM Friday as winds and
seas continue to ease.

As high pressure builds through the weekend, offshore flow
Saturday will turn northerly by Monday, generally at 10 kt or
less, although areas downstream of gaps in coastal terrain may see
locally stronger east winds. North to northwest winds at 10-15 kt
and seas of 5-8 ft are then favored through next week. -36

&&

.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Gale Warning until 6 PM PST this evening for PZZ210-271>273.
     Hazardous Seas Warning from 6 PM this evening to 2 AM PST
     Friday for PZZ210-271>273.
     Small Craft Advisory from 2 AM to 10 AM PST Friday for PZZ210-
     251>253-271>273.
     Gale Warning until 8 PM PST this evening for PZZ251>253.
     Hazardous Seas Warning from 8 PM this evening to 2 AM PST
     Friday for PZZ251>253.
&&

$$

www.weather.gov/portland

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