252
FXUS66 KSEW 171123
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
323 AM PST Mon Nov 17 2025

.SYNOPSIS...
Showers will continue across the region through Tuesday as a
series of disturbances cross the area. Drier weather is
expected late Tuesday into Wednesday as a ridge briefly builds,
giving a small chance for the first peaks of sunshine in a
short while. Rain chances will increase again late in the week
with a more significant round of precipitation possible late
next weekend.

&&

.SHORT TERM /TODAY THROUGH WEDNESDAY/...
Expect continued showers across the region this morning, with a
more robust disturbance remaining to the south of the area. This
will likely spread more widespread precipitation through the
region later today and tonight. While the bulk of the system
continues to remain positioned well to our south, will see an
embedded impulse provide a focus for heavier precipitation
tonight. This shouldn`t provide for much in the way of impacts,
but some snow down into the higher Cascade elevations can be
expected as snow levels begin to dip from around 6,000 feet to
around 3,500 ft Tuesday as moisture wanes. This could bring a
few inches down around Rainy Pass in the North Cascades, and
it`s worth noting that ensemble guidance continues to depict a
rather large spread in potential amounts (especially given that
we`re within 24-30 hours of the heaviest precipitation pushing
through). Will need to closely monitor satellite trends and
assess how high-res ensemble guidance is capturing this
evolution.

Otherwise, with the splitting system and favorable support
departing the region, expect to see a brief period of drier
conditions across the region as high pressure builds aloft. This
will bring some slightly cooler temperatures as the air mass
cools, but also the potential for a little sunshine between the
clouds for many Tuesday afternoon. Dry conditions likely
continue into Wednesday with the ridge remaining in place.
Depending on how the cloud cover evolves, will need to also
monitor the fog potential each of the next few mornings.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Expect the high pressure ridge to break down later in the week,
again opening the door for a return of a more active pattern.
Another system likely arrives around Thursday with additional
(possibly heavier) precipitation later in the weekend, though
ensemble guidance continues to show a wide spread in potential
outcomes with this next one. At the high end, there is some
potential for heavier snow in the high Cascades and possibly
bringing snow accumulations down to Snoqualmie and Stevens
passes, though it`s worth noting that some outcomes are
significantly less impactful. At the least, a return to more
widespread cloud cover and periods of precipitation is most
likely for the second half of the week.    Cullen

&&

.AVIATION...South-southwesterly flow aloft becoming variable
tonight. Flow aloft then turns west-northwesterly into Tuesday as an
upper-ridge builds offshore. Less fog around this morning due to
increased winds helping to scour near-surface saturation to some
degree. However, areas of low clouds remain with a mix of MVFR to
LIFR being observed. Terminals not under cloud coverage right now
are seeing VFR conditions.

HREF guidance indicates rainfall developing across Puget Sound by
12z. This precipitation in place will lead to continued lowered cigs
and vis with IFR/LIFR possible through 18-20z with MVFR to low-end
VFR thereafter. Rainfall will end by the evening, with a mix of
MVFR/IFR again overnight into Tuesday. Surface winds should keep fog
from developing but can`t rule out patches forming over terminals
such as KOLM and KPWT.

KSEA...Mainly MVFR to LIFR cigs so far this morning with transient
breaks to VFR. Rainfall is slated to develop over the terminal by
12z, helping to keep cigs and vis lowered to IFR to low-end MVFR
through much of the morning rush. A break to low-end VFR is possible
this afternoon between 20-23z but low-level moisture looks to
maintain tonight into Tuesday morning with more MVFR cigs favored.
SW winds turning NE this morning between 4-8 kt and maintaining
throughout the day before turning southerly again tonight.

McMillian

&&

.MARINE...
Winds remain gusty over the coastal waters and through the
central Strait of Juan de Fuca as a frontal system moves
through, with gusts around 25 kt through the morning. These
winds ease, but seas continue to run about 1-3 ft above guidance
over the coastal waters so will likely see SCAs continue for at
least the outer coastal waters if not all coastal waters
through much of the day. A break in the pattern likely emerges
toward midweek with high pressure maintaining less noteworthy
winds through the waters. However, expect another stronger
frontal system to bring at least high end advisory winds to the
waters by Thursday. Seas will also build over the coastal waters
into the 15-17 ft range later in the week. Expect the pattern
to remain active with additional disturbances impacting the
waters this weekend.    Cullen

&&

.HYDROLOGY...
No flooding is expected through the week ahead. A stronger
weather system next weekend could bring periods of heavier rain
and will be the next time to watch with respect to hydrologic
concerns.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 10 AM PST this morning for Central
     U.S. Waters Strait Of Juan De Fuca-Coastal Waters From
     Cape Flattery To James Island Out 10 Nm-Coastal Waters
     From James Island To Point Grenville Out 10 Nm-Coastal
     Waters From Point Grenville To Cape Shoalwater Out 10 Nm.

     Small Craft Advisory until 6 PM PST this evening for Coastal
     Waters From Cape Flattery To James Island 10 To 60 Nm-
     Coastal Waters From James Island To Point Grenville 10 To
     60 Nm-Coastal Waters From Point Grenville To Cape
     Shoalwater 10 To 60 Nm.

&&

$$