678
FXUS66 KPQR 272205
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
305 PM PDT Tue Oct 27 2026

.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.
Could see benign conditions into early next week before the
pattern becomes more unclear by the middle of next week.

&&

.SHORT TERM...Now through Wednesday Night...The wet and cool
pattern is expected to continue through the work week as
several weather systems impact the region. Stratiform
precipitation earlier today has transitioned to showers with the
passage of a cold front. Rainfall will vary across the forecast
area due to the showery nature of the precipitation, wettest
spots could see 0.10-0.20 inches through the evening. Shower
activity is expected to decrease this evening before the next
system moves in tonight. Ensemble models are in good agreement
that an upper level low over western Canada will slowly drop
south toward the PacNW. Models have this low centered just
offshore of WA and OR but several embedded shortwaves are
expected to pass overhead. Similar to today, expecting the bulk
of the rain late tonight into Wednesday morning before
transitioning to showers Wednesday afternoon. Rainfall totals
from 5 AM Wednesday to 5 AM Thursday are expected to be between
0.10- 0.60 inches, highest along the coast and in the higher
terrain and lowest south of HWY 20. There is a 20-50% chance
that areas in the SW WA and N OR Cascades could receive and inch
or more of rain during this time frame.

850 mb temperatures are expected to drop through Wednesday as
the upper level low brings cooler air with it. This will drop
snow levels to between 4000-4500 feet later this evening and
into Wednesday morning. This could bring snow to some of the
mountain passes which could create dangerous travel conditions
through the Cascades. For travel around Mount Hood, including
Government Camp, chances for 1 inch or more of snow from early
Wednesday through Thursday morning are 40-50%. During the same
period, chances are highest for Santiam Pass at over 90%. Snow
levels wednesday night into Thursday morning drop closer to
2500-3000 feet over the Cascades. However, this is expected to
be a relatively dry period so impactful snow over the passes is
not expected. -19

.LONG TERM...Thursday through Tuesday...Generally wet weather is
expected to continue Thursday and Friday as the upper level low
pinches off from the main flow and churns just off the coast of
WA and OR. QPF during this time period is quite low so looking
at a high PoP, low QPF set up which means we are likely to see
rain but it will be light. 48 hour totals across the area from
Thursday morning through Saturday morning likely 0.10- 0.30 inch
range. Locations along the coast and higher terrain could push
0.5 inches with a 20-40% chance. Ensembles and cluster analysis
point towards a drier pattern by the weekend and into early next
week. Models show the pattern becoming more progressive with
the closed low becoming an open wave and moving east Saturday
into Sunday with a shortwave ride building into the area by late
Sunday. Exact timing and details of this progression still vary
among the models. -19

&&

.AVIATION...Through 00Z Thursday...Showers continue to stream
across the region this afternoon with a mix of VFR to MVFR
conditions. While we`ll likely enter a lull in the shower
activity approaching sunset, another weather system dropping
towards the region from the Gulf of Alaska arrives later this
evening and overnight increasing shower frequency yet again.
From 04-08z onward, chances for MVFR conditions rise to 30-50%
at most sites coinciding with the arrival of this activity.
Should a heavier shower pass overhead, IFR conditions for a
brief period of time are also in play as well. Winds are
expected to increase along the coast and inland this evening out
of the S-SW with gusts up to 15-25 kt into Wednesday morning
before winds gain more of a westerly component and moderate
Wednesday afternoon.

KPDX AND APPROACHES...Conditions are currently a mix of VFR to
MVFR as a shower band passes overhead. After a lull by 00-01z,
showers increase again 06-08z increasing chances for MVFR
conditions by 12-14z Wednesday. Winds also increase out of the
south to southwest, peaking around the ~06-12z time period with
gusts around 20 knots expected before decreasing near midday
Wednesday. -99

&&

.MARINE...A low pressure system will keep conditions active
across the waters through the middle of the week. Currently an
upper-level low is dropping out of the Gulf of Alaska with winds
and seas increasing this evening out of the west to southwest.
Confidence is moderate to high for gusts to exceed 21 knots
across the inner and outer waters, especially north of Cape
Foulweather, thus a Small Craft Advisory remain in effect
including the Columbia River Bar as well. Seas likely peak
around 7-10 ft at 8-10 seconds this evening through Wednesday
evening. Then, conditions slowly subside Thursday into Friday
with gusts below 15-20kt and seas subsiding towards 4-6 ft at
10-12 seconds through the weekend. Looking towards the start of
next week, another low pressure system from the Gulf of Alaska
looks to bring building seas and winds that could result in
Small Craft conditions for the start of next week yet again.
-99/42

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...None.

WA...None.

PZ...Small Craft Advisory until 11 AM PDT Wednesday for PZZ210-251-
     252.

     Small Craft Advisory until 8 AM PDT Wednesday for PZZ253-273.

     Small Craft Advisory until 5 PM PDT Wednesday for PZZ271-272.
&&

$$

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