Milwaukie, Oregon 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

262
FXUS66 KPQR 022115
AFDPQR

Area Forecast Discussion
National Weather Service Portland OR
115 PM PST Mon Feb 2 2026

.SYNOPSIS...Decreasing showers across southwest Washington this
evening, with dry conditions elsewhere. High pressure ridge
builds over the Pacific Northwest on Tuesday, returning dry
weather through Friday. Clear skies and calm winds will promote
fog and frost potential across interior lowland valleys this
week. Some interior valleys may also experience air stagnation.
Easterly winds through the Columbia River Gorge will help
prevent air stagnation in the Portland/Vancouver Metro Area and
West-Central Willamette Valley.

&&

.DISCUSSION...Today through Sunday...Radar imagery and surface
observations as of early Monday afternoon depict rain across
southwest Washington as a weakening warm front lifts across
western Washington. Since this front is directed further north,
the majority of northwest Oregon will remain dry. High
resolution guidance suggests that rain will taper off into
light, scattered showers through this afternoon with conditions
eventually drying out by tonight as high pressure re-builds.
Mid to high level cloud cover will begin to scatter out,
favoring fog and/or low stratus development tonight across the
Willamette Valley where winds are expected to be calm. Some
light easterly winds through the Columbia River Gorge may
prevent fog development, particularly in the far eastern
Portland/Vancouver Metro Area. Will note that there is also
some uncertainty with exactly where low stratus may develop.
Some model soundings are showing east-southeasterly winds aloft
around 1000-2000 ft which would prevent stratus, while surface
winds remain calm or northerly under 5 mph. In this case,
locations with this set up would favor fog development than low
stratus. This would be more likely for areas not receiving the
easterly surface winds from the Gorge. If you will be commuting
through any fog tomorrow morning, make sure to slow down, use
low beam headlights, and leave plenty of distance between you
and other vehicles.

Beginning tomorrow (Tuesday), deterministic and ensemble
guidance remains in strong agreement that upper-level ridging
becomes firmly established over the Pacific Northwest. This
pattern will support an extended period of dry weather and
above-normal temperatures through at least Friday. High
temperatures are forecast in the upper 50s to low 60s, which is
around 10 degrees above normal for this time of year. Mid to
high level clouds will still linger over our area through
Tuesday afternoon as a system in the NE Pacific rides the
northwest periphery of the ridge and brings precipitation to
western British Columbia. However, clouds should clear out and
return sunny skies Wednesday to Thursday.

Winds will generally be light throughout this period of dry
weather, with the exception of the western Columbia River Gorge
and surrounding terrain. Tightening pressure gradients will lead
to breezy easterly gap winds, mainly on Wednesday and Thursday.
There is still some uncertainty with how tight the pressure
gradients between Troutdale and The Dalles will get, however
deterministic and ensemble guidance suggests pressure gradients
between these two places will be around -5 to -6 mb, potentially
up to -7 to -8 mb. Chances for maximum wind gusts exceeding 35
mph are around 20-40% across the far eastern Portland/Vancouver
Metro on Wednesday and Thursday, with higher chances of 70-90%
through the western Gorge and surrounding terrain. There is
also 30-50% chance that exposed ridgetops such as Three Corner
Rock and Crown Point experience wind gusts exceeding 50 mph.

For areas away from the Gorge, light winds and persistent
ridging will result in stagnant air conditions which could
affect air quality. An Air Stagnation Advisory has been issued
from 4 AM Tuesday to 4 PM Friday across the Southern Willamette
Valley, East Central Willamette Valley, North and Central Oregon
Cascade Foothills, North Clark County lowlands, and the Lower
Columbia River/Cowlitz River Valleys. Based on soundings and
model guidance, mixing heights in these locations are forecast
below 2000 feet with transport winds around 5 kt or less.
Decided to leave out the Portland/Vancouver Metro Area and West
Central Willamette Valley from the advisory as these areas will
remain better mixed from the increasing easterly winds this week
(these winds turn more northerly as it gets into West Central
Valley). Other than air stagnation, high pressure will maintain
chances for fog/frost this week across all interior lowland
valleys.

Chances for precipitation return this weekend, however there is
still uncertainty with the exact timing and precipitation
amounts. About 65% of ensemble members show precipitation
returning by Saturday afternoon, while the rest show
precipitation returning by Sunday afternoon. Most ensemble
members also show 500 mb heights decreasing this weekend, which
suggests that temperatures will also cool down. More details
will be ironed out this week, but either way it`s looking like a
wetter and cooler start to next week.          -10/12

&&

.AVIATION...A frontal system is moving through far NW OR and SW
WA Monday, producing showers near and north of KAST along the
coast and north of the Columbia River for inland areas. Showers
should end by 03-06z Tue. Mainly VFR conditions being observed
across the region with BKN/OVC mid to high level clouds north of
a line from KONP to KCVO. The exception is the far N OR/SW WA
coast where IFR/MVFR ceilings will continue through around
06-10z Tue. Expecting the mid/high level clouds inland to become
more scattered between 00-06z Tue from south to north. This
clearing will allow for fog/low stratus formation across
portions of the Willamette Valley. Areas south of KCVO,
including KEUG, could see fog formation as early as 06-09z Tue
as they will remain clear through most of the TAF period. For
locations north of KCVO, including KSLE, KUAO, and KHIO, there`s
a 40-60% chance of fog formation sometime between 06-12z Tue.
There`s more uncertainty for Portland area terminals depending
on wind direction. Some guidance suggests winds will remain from
the east through the entire TAF period, which would inhibit fog
formation, while other guidance suggests winds will briefly
turn north to northwesterly, which could allow for better
chances of fog formation. Any fog formation should improve to
VFR conditions by 18-21z Tue. Expect light winds mainly less
than 5 kts through the TAF period.

KPDX AND APPROACHES...Predominately VFR conditions through the
next 24 hours. Southeast winds around 10 kts calm to below 5 kts
after 23z Mon. There`s a 20-30% chance of fog formation between
11-16z Tue. Uncertainty is due to uncertainty on wind direction.
Some guidance suggests winds will remain from the east through
the entire TAF period, which would inhibit fog formation, while
other guidance suggests winds will briefly turn north to
northwesterly, which could allow for better chances of fog
formation. If fog does form, expect improvement to VFR
conditions by 18-20z Tue.        -03

&&

.MARINE...South winds with gusts 20 to 28 kts will slowly
decrease this afternoon behind this morning`s weak front. Expect
wind gusts to fall below 20 kts by 5 PM PST. Expect wave heights
of 10 to 13 feet at 12 to 15 seconds through this evening. Due
to a combination of winds and seas, a Small Craft Advisory is in
effect through 1 AM PST on Tuesday. High pressure builds over
the waters Tuesday with southerly winds less than 10-15 kts and
seas less than 10 ft. Winds remain mainly south to southwest
less than 10-15 kts through the rest of the week. By Wednesday,
an increasing westerly swell is forecast to push into the
waters, increasing seas to around 10-12 feet around 12-16
seconds through the end of the week.      -12/03

&&

.BEACH HAZARDS...A long period westerly swell will result in a
high threat for sneaker waves persisting through this afternoon.
Waves can run up significantly farther on a beach than normal,
including over rocks and jetties. Sneaker waves can suddenly
knock people off of their feet and quickly pull them into the
frigid ocean which may lead to serious injury or drowning.
Caution should be used when in or near the water, especially
those who will be razor clamming this week.       -42

&&

.PQR WATCHES/WARNINGS/ADVISORIES...

OR...Air Stagnation Advisory from 4 AM Tuesday to 4 PM PST Friday for
     ORZ108-115>118-123>125.

WA...Air Stagnation Advisory from 4 AM Tuesday to 4 PM PST Friday for
     WAZ204-205.

PZ...Small Craft Advisory until 1 AM PST Tuesday for PZZ210-251>253-
     271>273.
&&

$$

www.weather.gov/portland

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