365
FXUS66 KSEW 070514 AAA
AFDSEW

Area Forecast Discussion...UPDATED
National Weather Service Seattle WA
914 PM PST Sat Dec 6 2025

UPDATED AVIATION SECTION

.SYNOPSIS...
Active weather continues, with a certain increase in activity as
a strong atmospheric river arrives early next week. Heavy rain,
river flooding, wind and high elevation snow are in the forecast
for the foreseeable future. Minor coastal flooding due to high
astronomical tides will remain possible for the Salish Sea
coastline into the first part of the week.

&&

.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
KEY MESSAGES:

* RAIN: Following a weaker system moving through the area
  Sunday, a strong atmospheric river will bring several rounds
  of heavy precipitation to the area Monday and into Wednesday.
  The biggest change in the forecast is the main axis of
  moisture has shifted farther south into Southwest Washington,
  and overall QPF amounts through the 72-hour period have come
  down slightly. This has lowered the river forecasts a touch
  compared to yesterday, but the key message of widespread
  flooding has not changed. More details are below in HYDROLOGY.

* WIND: Breezy conditions are expected throughout the week, but
  the strongest winds are expected on Monday, on the onset of
  the atmospheric river event. Wind gusts of up to 30-45 mph are
  in the forecast across the area, though the strongest winds
  are expected along the coast, in southwest Washington, and
  through the Cascades.

* COASTAL FLOODING: Minor coastal flooding is expected through
  portions of the interior waters, mostly to the north. Compound
  flooding from high river flows by mid-next week may prolong or
  exacerbate the threat of coastal flooding.

Continued moist, onshore flow is maintaining scattered showers
across much of the region, except the central Puget Sound area
where the showers are getting shadowed. Snow levels continue to
remain just above pass level, allowing for rain at Snoqualmie
Pass and a rain/snow mix at the higher passes where temperatures
sit just a degree or two above freezing. Showers should taper
off this evening for a bit of break until the next system
arrives across the area early Sunday. The precipitation falling
on Sunday will be generally not impactful; amounts of up to a
quarter to a half of inch of rain through the interior, with up
to an inch or two in the mountains. These rains however, will
allow rivers to rise up a bit once again, and prime the soils
for what will arrive next week. Showers again may taper off
Sunday night but there will not be much of a break in the
precipitation.

The first push from the atmospheric river arrives to the area
early Monday. Rain will continue through much of the day before
beginning to sink southward Monday night.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
By Tuesday, most of the rain will be focused south of the area,
which may allow the northern half of the state to see a brief
break in at least the heaviest rain rates. However, another big
push of precipitation will move in late Tuesday into Wednesday.
This is the portion of the system that has shifted a bit farther
south. Models have also begun to come more into consensus that
another (albeit less impactful) system is forecast to arrive
Thursday night into Friday. What happens with this system (will
it be more progressive or will it stall out again over the
area?) is still unclear with more significant differences in the
forecast Friday and beyond.

In the main atmospheric river (72 hours from Monday -
Wednesday), amounts remain track with around 2-4" of rain
through the lowlands and along the coast, as well as 4 to 8 to
locally 10+" of rain over the mountains, with the heaviest
precipitation amounts across the southern half of the CWA. The
key message has not changed: widespread river flooding, as well
as urban and small stream flooding, remains a significant risk
across the entire area. See more below.

Temperatures will remain above average through the week, with
highs in the low to mid 50s and lows in the 40s.

62

&&

.AVIATION...
Active weather continues across the region as widespread showers
and low ceilings in place tonight. Expect mostly MVFR to IFR
ceilings to fill in across much of the interior overnight.
Surface winds will continue to ease tonight, but a few gusts
around 20 kt will continue around the southern portions of the
area south of KBFI through around 08z. The next frontal system
approaches to bring steadier rain (widespread MVFR to IFR
ceilings and reduced visibility) and gusty southerly winds to 25
kt during the late morning and afternoon hours.

KSEA...MVFR ceilings this evening with trend toward IFR likely
Sunday morning with rain as the next system approaches and the
air mass remains saturated. Gusty southerly winds with gusts to
20 kt easing after 08z tonight, but increasing again to 20-25 kt
late Sunday morning through the day.

&&

.MARINE...
Onshore flow will continue to ease across the area waters tonight
and waves currently between 12-15 ft will subside for a brief
break in between weather systems. Another frontal system will
move across the area waters on Sunday, bringing another round of
increasing southerly winds to the waters. At this time, winds
generally look to remain between 20-30 kt for most of the
coastal and interior waters. Winds will peak during the afternoon
hours again before subsiding. A stronger weather system will
then move into the waters Monday, likely bringing gales to
portions of the area waters. Additional weather systems will
move across the area mid to late next week.

Seas over the coastal waters will slowly subside to 9 to 11
feet by late tonight. Though, expect seas to build back towards
14-16 ft on Monday and remain elevated into midweek.

14

&&

.HYDROLOGY...
A series of wet weather systems moving across the region will
increase the threat of river flooding early next week. While
there`s still some uncertainty in the precipitation amounts
with an atmospheric river moving into the region, confidence
continues to increase that a widespread river flooding event
will commence late Monday and continue through much of the week.
Multiple rivers flowing off the Cascades and the Olympics are
forecast to reach Minor, Moderate, and Major flood stage. While
uncertainty does remain in regards to the exact flood levels
and stages through the next week, it will be critical to monitor
the forecasts through the next seven days. Additional precipitation
is also possible Thursday into Friday, which will keep rivers
elevated through the second half of the week.

The series of wet systems will also start to elevate the landslide
risk across the region. As soils become more saturated next week,
there will be an increased potential for landslides and debris
flows on burn scars.

Urban and small stream flooding, as well as areas with poor
drainage, should be alert to the potential for localized
nuisance flooding. Low water crossings may become impacted or
impassable.

14/62

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Coastal Flood Advisory from 5 AM to 11 AM PST Sunday for
     Lowlands of Western Skagit and Northwestern Snohomish
     Counties-Lowlands of Western Whatcom County-San Juan
     County.

     Coastal Flood Advisory from 6 AM to noon PST Monday for
     Lowlands of Western Skagit and Northwestern Snohomish
     Counties-Lowlands of Western Whatcom County-San Juan
     County.

     Flood Watch from late Sunday night through Friday afternoon
     for Cascades of Pierce and Lewis Counties-Cascades of
     Snohomish and Northern King Counties-Cascades of Southern
     King County-Cascades of Whatcom and Skagit Counties-City
     of Seattle-Downtown Everett / Marysville Area-Eastern
     Kitsap County-Eastern Strait of Juan de Fuca-Eastside-
     Foothills and Valleys of Central King County-Foothills
     and Valleys of Pierce and Southern King Counties-
     Foothills and Valleys of Snohomish and Northern King
     Counties-Foothills and Valleys of Thurston and Lewis
     Counties-Foothills and Valleys of the North Cascades-
     Foothills of the Western and Southern Olympic Peninsula-
     Grays Harbor County Coast-Island County-Lake Crescent
     Area Including US 101-Lower Chehalis River Valley-
     Lowlands of Lewis and Southern Thurston Counties-Lowlands
     of Pierce and Southern King Counties-Lowlands of Western
     Skagit and Northwestern Snohomish Counties-Lowlands of
     Western Whatcom County-Middle Chehalis River Valley-
     Northern Hood Canal-Northern Washington Coast-Olympia and
     Southern Puget Sound-Olympics-Port Townsend Area-San Juan
     County-Shoreline / Lynnwood / South Everett Area-Southern
     Hood Canal-Western Strait of Juan de Fuca-Willapa and
     Black Hills.

PZ...Small Craft Advisory until 10 PM PST this evening for Grays
     Harbor Bar.

     Small Craft Advisory until 4 PM PST Sunday 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.

     Small Craft Advisory from 7 AM to 4 PM PST Sunday for
     Admiralty Inlet-East Entrance U.S. Waters Strait Of Juan
     De Fuca-Northern Inland Waters Including The San Juan
     Islands-Puget Sound and Hood Canal.

     Gale Watch from Monday morning through Monday evening 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.

&&

$$