Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
929
FXUS66 KSEW 202135
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
235 PM PDT Mon Apr 20 2026
.SYNOPSIS...
Warm and dry conditions will continue through today before
cooler temperatures and increased chances for precipitation
arrives midweek. Warmer and drier conditions look to return
later through the week and into the weekend.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
Generally pleasant conditions this afternoon as warm and dry
conditions continue over the region. High temperatures this
afternoon generally in the low to mid 70s across the interior,
with locations along the water seeing mid to upper 60s.
A deep upper level low continues to meander offshore and will
shift further inland on Tuesday, allowing for wrap around
moisture to move into western Washington. This will allow for
showers to move northward throughout the area on Tuesday and for
cooler temps in the upper 50s and lower 60s. There will also be
instability from the aforementioned upper level low, so we could
see some isolated thunder Tuesday afternoon/evening, but mainly
confined to the Cascades. Snow levels will remain above 5000 to
6000 feet with minimal accumulating snow over the higher peaks.
This trend continues into Wednesday with scattered showers
across most of the area and high temperatures in the mid 50s.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
Shower activity will decrease heading into Wednesday night as an
upper level ridge develops offshore. Ensemble guidance shows a
warming and drying trend through the end of the week and heading
into the weekend, with temperatures warming back up into the
upper 60s and potentially low 70s. Models do show some
disagreement on the strength of the ridge and how long the
conditions remain dry for.
Mazurkiewicz
&&
.AVIATION...
Southerly flow aloft will continue into Tuesday as a cutoff upper
level low off the northern California coast gradually shifts
eastward. A combination of developing low level onshore flow and
moisture wrapping around this system will lead to increasing shower
activity along with lowering ceilings across the area on Tuesday.
Ceilings are expected to lower to MVFR along the coast overnight
then spread northward across interior areas Tuesday morning. These
conditions will then persist into Tuesday night and beyond.
KSEA...VFR conditions will continue into this evening. Ceilings will
lower overnight and are expected to become MVFR by around mid-
morning Tuesday with showers in the vicinity of the terminal by
afternoon. Surface winds will become S/SW 4 to 8 knots this evening
and continue overnight. Winds will rise to 10 to 15 knots at times
Tuesday morning. 27
&&
.MARINE...
Weak low pressure will remain over the inner coastal and interior
waters into midweek with broad high pressure remaining well
offshore. A modest increase in onshore flow on Tuesday is expected
to produce small craft advisory winds in the central and east
portions of the strait. Gusty north to northwesterly winds and
steepening seas are expected over the outer coastal waters on
Wednesday. Winds ease, seas subside and the flow turns more
northerly late this week in response to a strengthening surface
ridge over British Columbia. 27
&&
.HYDROLOGY...
No river flooding is expected over the next 7 days
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...None.
&&
$$
NWS SEW Office Area Forecast Discussion