Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
039
FXUS66 KSEW 280354
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
854 PM PDT Fri Mar 27 2026
.SYNOPSIS...
High pressure under a zonal flow will keep western Washington
quiet through the first part of the weekend. A trough will bring
the next chance of showers Sunday into Monday, including light
snow in the mountains. The zonal jet will shift eastward,
inviting additional systems to pass through next week, with
chances of showers.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
It remains dry across western Washington this afternoon. The
zonal flow pattern with the upper level jet remains in place
today, with high pressure at the surface. High cirrus clouds on
satellite are tracking inland from a weak front offshore to the
northwest (over north Victoria B.C.). Temperatures this
afternoon have reached the low to mid 50s, and Saturday is
shaping up to be similar to Friday (albeit with a few more
clouds that will roll in tonight and linger Saturday). A couple
patches are fog can`t be ruled out Saturday morning (as the
cloud deck is expected to remain high in altitude and thin in
coverage, but will gradually lower through the night).
Temperatures tonight/Saturday night will be a few degrees warmer
with the help of the cloud coverage (upper 30s-low 40s). Winds
will be light and variable and calm at times through the
weekend.
The next system is expected to arrive Sunday and linger into
Monday, as the zonal jet and high pressure move out of the
region. A weak upper level low will drop a trough behind the jet
streak, which will bring the next chance of showers across the
region (snow showers for elevations greater than roughly 1,500
ft). The trough will drag a cold front across the region during
the day. Cooler air will sink in behind the front, with highs
Sunday only reaching the upper 40s/low 50s, and lows dipping
back to the upper 20s/low 30s. The moisture available with this
front is limited, which will keep lowland rain accumulations to
several hundredths to a few tenths of an inch, and the
mountains seeing light amounts of snow (couple inches at the
passes Sunday into Monday - 2-4 inches at higher elevations).
The peaks of the mountains have a 50-60% chance of having snow
accumulations greater than 6 inches (areas such as Paradise, Mt.
Baker and Glacier Peak).
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
The ensembles are in good agreement with the trough Sunday
continuing to push through the region Monday. The precipitation
chances decreases to near 0 late Monday into early Tuesday as
any post-front convergence zone activity moves out. Breaks in
the cloud coverage are likely, with temperatures slowly warming
up Monday into Tuesday, with highs returning into the low to mid
50s. The air will dry out substantially Monday/Tuesday with
light east/northeast winds Monday into Tuesday (some areas may
see RH values dip down to as low as 40%).
The model agreement continues midweek, with nearly all of the
models having a more vigorous shortwave trough passing through
Wednesday. This system (if it remains on track) will produce a
steady amount of precipitation from late Tuesday through
Thursday. This includes mountain snow, with snow levels around
2,000 to 3,000 ft. Probabilities for more than 8 inches of snow
at the passes with this system remains low at this time
(15-30%). Temperatures will hold steady for the remainder of the
week in the upper 40s to low 50s, with lows in the upper 30s to
low 40s. A few areas Wednesday may see breezy winds up to 20-30
mph from the southwest as the midweek system passes through.
HPR
&&
.AVIATION...
Westerly flow aloft will prevail through Saturday. VFR cigs are
expected to prevail throughout the TAF period for all terminals
with mid to high cloud cover streaming in overhead. Winds are
expected to remain northerly at the surface, decreasing from
8-10 kt this evening, to 4-6 kt after 06Z. By Saturday morning,
expect winds to turn westerly for interior terminals and then
become northwesterly in the afternoon.
KSEA...VFR conditions will persist through the TAF period with
mid to high clouds streaming overhead. Northerly winds between
8-10 kt this evening will come down after 06Z to between 4-6
kt and shift to the east-northeast. While still VFR, there will
be a SCT to FEW layer at 040 to 050 Saturday morning after 12Z,
lingering into the early afternoon. Winds during this time will
become west-southwest at 4-6 kt.
21/14
&&
.MARINE...
Northerly winds across the inner coastal waters are breezy
tonight, gusting to 20-25 kt at times, however will gradually
ease over the next few hours. Winds will prevail out of the
north/northwest across the area as high pressure remains
situated over the coastal waters into the weekend. A weak front
will pass by to the northwest Saturday and dissipate as it does
so. A weak push down the Strait of Juan de Fuca will ensue
Saturday evening. A disorganized low pressure system will move
across the waters Sunday into early Monday, but stronger high
pressure building behind it could raise winds through the
coastal waters above 20-25 kt early on Monday. A stronger system
looks to move into the region around mid-week, which looks to
bring the next round of gustier winds and building seas to the
area waters.
Seas generally remain around 5-8 ft before increasing towards
10-14 ft Wednesday into Thursday as the stronger system moves
into the waters.
21/14
&&
.HYDROLOGY...
No river flooding is expected in the next 7 days.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...None.
&&
$$
NWS SEW Office Area Forecast Discussion