681
FXUS66 KPQR 270502 AAA
AFDPQR

Area Forecast Discussion...UPDATE
National Weather Service Portland OR
1001 PM PDT Mon Oct 26 2026

Updated Aviation discussion

.SYNOPSIS...Seasonably cool and showery conditions continue
through the workweek as repeated weather systems support
persistent chances for rain. A drying trend beginning Friday
may bring better trick-or-treating conditions by late Saturday.

&&

.SHORT TERM...Now through Tuesday...A vertically stacked surface
and upper-level closed low, currently centered about 30 miles
west of Astoria as of 2 PM PDT Monday, will continue to slowly
push eastward and inland over the north Oregon coast this
evening. Scattered to numerous rain showers ongoing this
afternoon will diminish in coverage late this evening as the
upper feature passes overhead, but an upper shortwave which will
approach the coast will see another round of increased showers
from tonight through midday Tuesday. Observed 36-hour rainfall
totals through midday Monday have generally ranged from 0.75-1.5
inches, with slightly lower amounts near 0.5 inches on the east
side of the Coast Range and the highest totals of 1.5-2.5 inches
on the west slopes of the Coast Range and Cascades. Additional
rainfall of 0.25-0.5 inches is most likely through Tuesday,
with up to 1 inch in favored upslope enhancement areas on the
west/southwest slopes of area terrain. Snow levels around 5500
ft as of midday Monday will fall closer to 5000 ft by early
Tuesday morning, allowing for light accumulations at pass level.
Chances for 1 inch of snow at Santiam and Willamette Passes
through midday Tuesday remain 50-60%, with only 15% chances at
passes near Mt. Hood. Seasonable temperatures continue across
the region with afternoon highs in the 50s and early morning
lows in the upper 30s to mid 40s. -36

&&

.LONG TERM...Tuesday Night through Monday...Another, broader
closed upper low and its associated surface low will drop south
from the Gulf of Alaska over Vancouver Island and into the
Pacific Northwest from Tuesday night into Wednesday morning.
This will bring another round of precipitation to the region
through Friday. Falling mid-level temperatures will see snow
levels decline to around 3500 ft by Thursday morning, with a 10%
chance of falling all the way to 2500 ft. This will support
35-65% chances for 2 inches of snow at Cascade passes, highest
at Santiam Pass, but 5% or lower chances of 6 inches. Those
planning travel through the Cascades should prepare for winter
driving conditions. At lower elevations, another 0.5-1.0 inches
of rain is most likely, with lower amounts of 0.25-0.5 inches on
the east slopes of the Coast Range and higher amounts of 1.0-2.0
inches on the western and southwestern slopes of area terrain.

From Friday through the weekend, upper-level ridging is favored
to build into the region from the west, supporting a drying
trend locally. While chances for rain therefore decrease through
the day on Saturday, there continue to be about 20% chances for
lingering rain showers for Halloween trick-or-treaters in the
afternoon and evening. The drying and clearing trend will allow
for colder overnight temperatures beginning Friday night, with
upper 20s to mid 30s most likely for most inland valleys nightly
through the weekend and into early next week. -36

&&

.AVIATION...Through 06Z Wednesday...Moist, westerly flow aloft
continues tonight into Tuesday morning as an upper level trough
moves over the region. A mix of VFR to MVFR conditions persists
through this evening across the area. After a brief lull, showers
increase again overnight while flight conditions trend toward
predominately MVFR. Brief periods of IFR will also be possible,
though generally just a 10-20% chance at any given hour.
Conditions are likely to improve after 19-21z Tuesday as showers
decrease and CIGs lift toward VFR. Winds generally remain south to
southwest at 5-10 kt.

KPDX AND APPROACHES...A brief lull in showers with low-end VFR
trends toward more MVFR conditions after 06-08z Tue. Shower
activity expected to increase after 08z with chances for MVFR CIGs
and VIS bouncing between 40-70% through 20z Tue. Predominately VFR
likely returns by 21-23z Tue as showers decrease again. Southwest
winds expected around 3-7 kt through the period. /DH

&&

.MARINE...Surface low pressure continues to slowly drift eastward
into the north Oregon coastline with winds and seas easing. On
Tuesday, another weather system drops southward from the Gulf of
Alaska introducing a reinforcing northwesterly swell late Tuesday
into Wednesday while also increasing wind gusts to 20-25 knots
north of Cape Foulweather. There continues to be 10-35% chance for
seas to meet or exceed 10 ft on Wednesday with the highest
relative probabilities for the waters beyond 10 NM. Seas slowly
subside Thursday into Friday ending up back in the 4 to 6 ft
range at 12-13 seconds by Saturday. DH/99

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.
WA...None.
PZ...Small Craft Advisory from 5 PM Tuesday to 11 AM PDT Wednesday
     for PZZ210-251-252.

     Small Craft Advisory from 8 AM Tuesday to 2 PM PDT Wednesday for
     PZZ271-272.

&&

$$

www.weather.gov/portland

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