Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
010
FXUS66 KSEW 131149
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
349 AM PST Sat Dec 13 2025
.SYNOPSIS...
Significant river flooding continues across many areas of
western Washington. Drier conditions develop today, but a weak
front crosses the region by early Sunday. A stronger system
will follow Monday into Tuesday with heavier precipitation and
potentially strong winds for some areas. A deeper trough will
bring a cooler air and the potential for heavy mountain snow
Tuesday and Wednesday.
&&
.SHORT TERM /TODAY THROUGH SUNDAY/... High pressure building
over the region maintaining a stable air mass with light winds,
along with drier conditions. Numerous rivers remain above flood
stage and resulting impacts from river flooding will continue
today. Expect some areas of fog to develop early this morning
toward daybreak, though a persistent cloud deck may prevent
visibilities from becoming significantly restricted. The ridge
flattens out into Sunday with a weak system sliding across the
area. This will reinforce the cloud cover and bring some light
precipitation to portions of the area. Snow levels remain high,
but amounts are light enough to not bring much in the way of
impacts or concern. 12
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
A different story emerges Sunday night into Monday, when the
next atmospheric river taking aim at the region. Snow levels
will remain rather high at the onset (above 7500 ft), and
rainfall amounts look be be on the order of around an inch for
the lowlands and 2-4 inches in the mountains through late
Monday, with the mountain amounts highest in the Cascades from
around King County northward. This would have the potential to
bring prolonged or renewed flooding on many areas rivers. Gusty
winds also are likely to increase with this frontal system with
gusts reaching 30-40 mph remaining likely (>60% chance) through
the coastal and favored windy locations in the interior. The
pattern stays active and rather damp through much of the week
ahead, but the arriving trough will bring snow levels dipping
down to below the Cascade passes through the day Tuesday and to
around 2500 ft Wednesday. This will set the stage for potential
heavy snowfall in the mountains during the midweek time period.
Meanwhile, this will bring additional rainfall to the lowlands
through much of the week ahead with a moist and active weather
pattern remaining in place. 12
&&
.AVIATION...
Upper level ridge over Western Washington with the ridge axis
moving east of the area later this morning. Westerly flow aloft
becoming southwesterly late morning. Light flow in the lower
levels.
Real mixed bag out there this morning. Stratus deck between 3000
and 6000 feet preventing the scattered cloud deck below 1000
feet from becoming ceilings. With the light flow will go for
ceilings lowering down to IFR 14z-16z. Ceilings improving in the
afternoon with just middle and high level clouds by 01z. Cloud
deck around 5000 feet developing overnight with the upper level
ridge continuing to move east and a weakening front approaching the
coast.
KSEA...Ceilings near 4000 feet lowering to below 1000 feet
around 15z. Could see some visibility restrictions down to as
low as 3 sm. Ceilings lifting this afternoon with VFR ceilings
by 01z. Light south southeast wind 6 knots or less. Felton
&&
.MARINE...
A weak front will cross the waters later today through early
Sunday, with advisory strength winds expected over the coastal
waters. A stronger system arrives Sunday night into Monday and
is more likely to bring widespread advisory winds to all waters
and some potential (40-50%) for gales over the coastal waters.
Seas will increase with these stronger winds late Sunday/Monday,
and with the arrival of larger swell at the same time, expect to
see 15-20 ft seas across the coastal waters early in the week.
Yet another disturbance in the Pacific parade of weather systems
will bring a reinforcing round of winds and again building seas
around midweek. 12
&&
.HYDROLOGY...
Rivers continue to recede this morning as Western Washington
gets a break from the wet weather. Even the lower reaches of the
rivers will approach or lower below flood stage later today into
tonight. The exception to this will be the lower reaches of the
Chehalis river which will not fall below flood stage until
Sunday from Porter down to Grays Harbor and the lower reaches of
the Skagit river which will recede to near flood stage by
Monday morning.
Rivers will be on the rise again later Monday into Tuesday with
another atmospheric river taking aim at Western Washington.
Rainfall amounts to 3 to 5 inches Monday through Wednesday in
the mountains are forecast. Another round of river flooding
will occur with the atmospheric river but at this time none of
the forecasts have any major flooding on the rivers ( the Skagit
at Mount Vernon gets close Tuesday night and the Snoqualmie at
Carnation gets close Wednesday ).
With very wet antecedent soil conditions, the landslide threat
remains high across the region. Potential is also elevated for
debris flows over area burn scars, which continue to be
monitored.
The threat of urban flooding will increase again later Monday
into Tuesday. Small stream flooding, as well as areas with poor
drainage, will pose a risk of localized nuisance flooding and
ponding on roadways later Monday into Wednesday. Felton
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory from 4 PM this afternoon to 1 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.
&&
$$
NWS SEW Office Area Forecast Discussion