Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
416
FXUS66 KSEW 121705
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
905 AM PST Fri Dec 12 2025
.SYNOPSIS...Lingering light precipitation will lift north of
the area through the day. Elevated river runoff conditions will
continue with significant river flooding impacts for many areas.
Saturday will see needed drier weather ahead of a weak frontal
system Saturday night into Sunday. A stronger system will follow
Monday into Tuesday with heavier precipitation and potentially
windy conditions for some areas.
&&
.SHORT TERM /TODAY THROUGH SUNDAY/...
Areas of light rain mainly over the Cascades and northern
Olympic Peninsula lingering this morning. Light rain will shift
north into British Columbia as upper level ridging begins to
move onshore late in the afternoon and evening. The upper level
ridge will give the area a need break in precipitation during
the day Saturday.
A weak frontal system will bring precipitation back to the area
Saturday night into Sunday with a 30-50% chance of 1 to 2 inches of
precipitation falling over the Olympics and northern Cascades
through Sunday evening. Snow levels are expected to be above 5500
feet through this period and given the antecedent hydrologic
conditions throughout the area has the potential to result in
impacts to area rivers.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Ensembles continue to consistently bring a stronger system back
into western Washington quite literally on the heels of the
late weekend system. This would return widespread, heavier
rainfall to the area as well as windy to gusty conditions for
parts of western Washington. Interestingly, long range ensemble
clustering does indicate several scenarios associated with
differences in the upper level pattern, however each of these
patterns result in similar precipitation forecasts over much of
the Pacific Northwest - including western Washington. Snow
level forecasts remain high - 7,000 to 8,000 feet - for much of
Monday, so that the initial push with this system would fall as
rain over most of the higher terrain. The National Blend of
models is currently showing a 30-60% chance of 3 to 4 inches of
precipitation over the Olympic and the Whatcom, Skagit and
Snohomish Cascades through Monday evening. If this occurs it
would contribute to renewed or prolonged flooding impact to many
area rivers. Similarly the NBM showing 80-90% probabilities of
wind gusts greater than 45 mph along the coast, and 60-80% odds
over the area of Admiralty Inlet to western Whatcom County.
The persistent large scale pattern of broad troughing over the
northern Pacific through increases the likelihood of active if
not impactful weather through much of the remainder of the week.
This could include periods of widespread rain, high- elevation
snow and even winds.
&&
.AVIATION...
Majority of terminals IFR to LIFR this morning and seeing
visibilities generally between 1-3SM. Limited improvement is
expected by the afternoon towards MVFR for most terminals. Some
guidance is hinting seeing brief improvement towards low-end VFR
this evening, but confidence is low at this time. IFR/LIFR
conditions expected to return overnight.
KSEA...IFR conditions at the terminal this morning with visibilities
as low as 1.50SM. Expecting to see gradual improvement by the
afternoon but only to MVFR with ceilings at or below 2500 feet. May
potentially see low-end VFR ceilings briefly this evening, but not
confident to include in the prevailing line. IFR/LIFR conditions
expected to return overnight. Southwesterly surface winds increasing
this afternoon to 5-7 kt.
29/27
&&
.MARINE...
A weak surface ridge will remain over the coastal and interior
waters today. The first of a series of fronts will approach the
coastal waters late Saturday. A series of vigorous frontal systems
will impact area waters early next week with headlines for both
winds and hazardous seas.
Seas will climb back into double digits Sunday night into Monday
and remain hazardous for the foreseeable future. 27
&&
.HYDROLOGY...
Many rivers continue to run at significant or near record
levels, especially over the western Cascades. Those rivers that
are slower to respond, including the Nooksack, Skagit, and
Snohomish, will take a few more days to fully crest and lower
below flood stage.
* Numerous River Flood Warnings remain in effect across western
Washington, with varying times and flood levels.
* A Flash Flood Watch remains in effect for a potential levee
failure of the Skagit River below Sedro-Wooley to the mouth of
the Skagit River through late Friday.
* A Flood Watch remains in effect through Friday across all of
western Washington.
With very wet antecedent soil conditions, the landslide threat
across the region has increased with this system, and several
landslides and mudslides have already occurred in steep terrain
across western Washington. Potential has also increased for
debris flows over area burn scars, which continue to be
monitored.
While the threat of urban flooding has decreased, the threat of
small stream flooding, as well as for areas with poor drainage,
continues to pose a risk of localized nuisance flooding and
ponding on roadways. Low water crossings may become impacted or
impassable.
The latest river observations and forecasts can be found at
water.noaa.gov.
33/15
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Flood Watch until 4 PM PST this 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.
Flash Flood Watch through late tonight for Lowlands of Western
Skagit and Northwestern Snohomish Counties.
PZ...None.
&&
$$
NWS SEW Office Area Forecast Discussion