Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
722
FXUS66 KSEW 050459
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
859 PM PST Sun Jan 4 2026
.SYNOPSIS...
Unsettled conditions will persist across western Washington
through Monday as troughing continues over the region. A series
of strong frontal systems will bring heavy mountain snow, breezy
winds, and widespread lowland rain Tuesday through Thursday
before an upper ridge builds over the western US.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY NIGHT/...
A shortwave offshore will continue to spread light shower
activity across the interior this evening. Upper level troughing
will shift inland tonight into Monday, maintaining scattered
showers overnight and into the morning. A cooler air mass will
move into the region, dropping temperatures into the 30s
overnight and allowing snow levels to lower to 2500 to 3000
feet. Shower activity will taper off Monday afternoon,
providing a brief lull before the next incoming system. Major
coastal flooding has ceased this afternoon along the Pacific
Coast and northern Salish Sea coastlines, with minor to moderate
coastal flooding elsewhere. Astronomical tides will continue to
lessen from this point, with minor to moderate coastal flooding
set to continue over the next few days.
A strong frontal system will cross the region on Tuesday,
bringing the next round of significant weather. While winds will
become quite breezy as the cold front digs into western
Washington, some uncertainty remains over how windy conditions
will be. The main story will be snowfall, and with snow levels
lowering well below pass level to near 1500-2000 feet, the
mountains are on track to see significant snowfall with this
system. Forecast models continue to show 24-hour snowfall totals
on the order of 1 to 2 feet Tuesday morning through early
Wednesday morning, with heavy accumulations through the central
Cascade passes. For the lowlands, Tuesday will be a damp and
windy day with rainfall totals ranging generally from a half
inch to an inch.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
Precipitation will briefly taper on Wednesday as the frontal
system shifts east of the Cascade crest. Another strong weather
system will be right on its heels, bringing another round of
heavy precipitation to the region Wednesday through Thursday.
This system will likely bring an additional couple of feet to
higher elevations of the Olympics and Cascades, bringing storm
totals to 3 to 4 feet of snow. A Winter Storm Watch has been
issued from Tuesday morning to late Thursday evening as
confidence grows over the potential for significant mountain
snow. The lowlands will see another round of rain reaching a
half inch to an inch during this period.
Forecast confidence decreases towards next weekend as an upper
level ridge builds over the western US. Conditions may dry out
next weekend, but models continue to show potential for another
wet system overrunning the ridge and bringing more precipitation
to the region. While a chance of lowland rain and mountain snow
remains in the long range forecast, temperatures next weekend
will warm up and may reach the low 50s for some areas.
15
&&
.AVIATION...
A surface low remains offshore just west of KHQM this evening,
with widespread showers wrapping around through the region.
Expect the flow aloft to turning increasingly westerly as the
upper trough slides inland tonight. This will maintain scattered
showers for most of the region, though a few bands of heavier
showers closer to the low center will likely bring heavier rain
and lower ceilings/visibility through around 06z near the coast
and 06-10z for the southern Puget sound terminals south through
KOLM/KCLS. Elsewhere, continued scattered showers and steady
lower VFR to MVFR ceilings will remain. Predominantly southerly
surface winds this evening, though some variability in
direction near the surface low as it tracks inland can be
expected.
KSEA...VFR ceilings this evening with scattered showers. Expect
a heavier line of rain 06-09z associated with passing low that
will bring ceilings/visibility into MVFR range. Expect residual
moisture to maintain ceilings around 1500 ft or so into the
morning push before gradually lifting through the day.
12
&&
.MARINE...
Weak high pressure will start to build over the waters tonight
into Monday, leading to decreasing seas and winds over the area
waters. A stronger weather system will cross over the area on
Tuesday, leading to increased south/southwesterlies over the
coastal waters, along with increased southerlies over the
interior waters, likely small craft advisory strength. These
winds look to continue through Wednesday.
Surface high pressure looks to build over the area Thursday into
Friday which would help marine conditions calm down a bit.
Coastal seas 6 to 8 feet this afternoon decreasing into Monday.
Seas will build again on Tuesday, building upwards to the 14 to
18 foot range, with the highest seas being in the outer coastal
water zones. These elevated seas will continue through
Thursday.
Mazurkiewicz
&&
.HYDROLOGY...
The Skokomish River is expected to crest this evening just below
flood stage and continue to fall into Tuesday morning. It is
expected to crest above minor flood stage later Tuesday with
additional precipitation entering the region. For the remainder
of area rivers no flooding is expected over the next 7 days.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Coastal Flood Advisory from 6 AM to 10 AM PST Monday for
Island County-Lowlands of Western Skagit and Northwestern
Snohomish Counties-Lowlands of Western Whatcom County-San
Juan County.
Winter Storm Watch from late Monday night through Thursday
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.
Coastal Flood Advisory from 5 AM to 9 AM PST Monday for City
of Seattle-Downtown Everett / Marysville Area-Eastern
Kitsap County-Lowlands of Pierce and Southern King
Counties-Shoreline / Lynnwood / South Everett Area.
Coastal Flood Advisory from 11 AM to 3 PM PST Monday for
Eastern Strait of Juan de Fuca-Grays Harbor County Coast-
Northern Washington Coast-Western Strait of Juan de Fuca.
PZ...None.
&&
$$
NWS SEW Office Area Forecast Discussion