073
FXUS66 KSEW 012226
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
226 PM PST Sun Nov 1 2026
.SYNOPSIS...
High pressure overhead will maintain dry conditions, cloudy
skies, and areas of patchy fog through Monday morning. A series
of splitting systems will bring slight chances of rain to
western Washington Monday and Tuesday ahead of a series of
systems that will bring increasingly more lowland rain, mountain
snow, and breezy winds through the end of next week.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
Low stratus continues to remain firmly entrenched over the
interior lowlands this afternoon, with some patches of sun
breaking through the cloud deck. However, any sun breaks will be
short lived with clouds filling back in this evening aided by
high pressure aloft and light winds. Residual moisture from
recent rains will also result in patchy fog early Monday
morning, which may pose localized visibility limitations during
the morning commute for fog-prone areas. However, light
easterly winds in the early morning may help to reduce fog
formation under the stratus. As the upper level ridge axis
nudges eastward on Monday, light rain showers offshore will
slide inland Monday evening, though rainfall amounts will be
very light. As a cutoff low develops to the south Monday night
into Tuesday and weak ridging develops offshore, moisture will
be nudged out of the area, allowing warmer and drier conditions
to briefly settle in for most areas by Tuesday afternoon.
However, sunny skies may be few and far between through Tuesday,
with temperatures near or a few degrees above normal.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Ensembles continue to show good agreement over a series of
increasingly stronger systems passing over the region as the
rest of the week goes on. A frontal system on Wednesday is
expected to bring a round of widespread rain and high elevation
snow to western Washington, with the bulk of the moisture
focused over the Olympic Peninsula and North Cascades. Areas
east of the Olympic Mountains will likely see a high degree of
rain shadowing with this system, resulting in only a few
hundredths of rain accumulation.
Another weather system will follow closely behind, and will be
stronger than Wednesday`s system. While shadowing will occur
once again east of the Olympics, higher elevations will see
roughly half of an inch to an inch of liquid while the lowlands
see a tenth or two of rain accumulation into Friday morning.
Snow levels will hover around 5000 feet as this system passes
through, resulting in a few inches of additional snow
accumulation over higher terrain.
Forecast confidence decreases into next weekend, depending on
how far northward an upper level ridge will build over the
western US. The ridge could either keep conditions warm or dry,
or remain too weak to ward off an incoming atmospheric river
system. While the bulk of the moisture of this system looks
like it might make landfall over British Columbia, western
Washington may see some of the heaviest rain so far this fall
with up to 2 to 3 inches of liquid over the mountains and
generally a half inch to an inch over the lowlands. The vigorous
system could also bring widespread breezy winds alongside the
precipitation if the storm takes aim at the Pacific Northwest,
and waves could inch towards High Surf criteria along the
immediate coastline.
Beyond next weekend, longer range models continue to show
potential for high winds, heavy rain, and heavy snow across the
Pacific Northwest during the second week of November. While
conditions remain highly uncertain at this time, potential
impacts will continue to be monitored as we settle into the
month of November.
15
&&
.AVIATION...
A mix of VFR and MVFR this afternoon, as the stratus continues to
slowly erode this afternoon over Puget Sound terminals. Still
expecting improvement around 23Z-00Z. Another round of IFR/LIFR
stratus and fog is possible Monday morning. Residual moisture from
recent rains will result in patchy fog, which may pose localized
visibility limitations in fog-prone areas. However, light easterly
winds and mid to high clouds moving inland Monday morning may help
reduce fog formation, instead resulting in low stratus. Improvement
to VFR after 18Z-20Z. Light northerly surface flow, becoming more
light and variable tonight.
KSEA...The stratus continues to slowly burn off this afternoon, with
improvement to VFR likely after 23-00Z. Low clouds below 1000 ft are
possible (50-55% chance) Monday morning. Additionally, light
easterly winds and mid to high cloud cover should limit the
potential of fog at the terminal. Clouds expected to lift after 19Z
for VFR conditions in the afternoon. Light NW winds this afternoon
at 5 kt or less, becoming NE in the evening.
29
&&
.MARINE...
High pressure will continue building over the waters through Monday.
A weather system will brush the coastal waters Monday morning,
leading to an increase in southerly surface winds. Winds gusts may
briefly approach 21 kt at times over zones PZZ170 and PZZ173 through
the afternoon hours. High pressure will move inland on Tuesday ahead
of the next system that arrives on Wednesday. Southerly winds will
increase over the coastal waters on Wednesday with a 55-80% chance
of small craft winds. A stronger system will arrive on Friday,
bringing stronger winds across the coastal waters and the interior
waters. Latest guidance suggests a 70% chance or higher for small
craft winds and a 25-40% chance of gales. Another system expected on
Saturday with the potential (50-75% chance) for small craft winds
over the coastal waters and interior waters.
Seas around 3-5 feet today will continue building to 8-11 feet by
Monday morning, for which a Small Craft Advisory has been issued
through early Tuesday morning. It is likely that Small Craft
Advisory may have to be extended for the outer coastal waters, as
seas around 10 feet look to linger through late Monday morning. Seas
will decrease below 10 ft late Tuesday, before increasing above 10
feet on Thursday. Seas continue to trend higher with the system
Friday, with latest guidance now suggesting seas around 15-20 feet.
29
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory from 1 AM Monday to 1 AM PST Tuesday for
Coastal Waters From Cape Flattery To James Island 10 To
60 Nm-Coastal Waters From Cape Flattery To James Island
Out 10 Nm-Coastal Waters From James Island To Point
Grenville 10 To 60 Nm-Coastal Waters From James Island To
Point Grenville Out 10 Nm-Coastal Waters From Point
Grenville To Cape Shoalwater 10 To 60 Nm-Coastal Waters
From Point Grenville To Cape Shoalwater Out 10 Nm-West
Entrance U.S. Waters Strait Of Juan De Fuca.
&&
$$
NWS SEW Office Area Forecast Discussion