Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
430
FXUS66 KSEW 292209
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
309 PM PDT Fri May 29 2026
.SYNOPSIS...
Onshore flow will continue in wake of the cold front the passed
through overnight. Afternoon showers in the Puget Sound will
dissipate later tonight, with cooler temperatures continuing
through the weekend. A warm and dry pattern moves in Monday
through Wednesday, with temperatures peaking on Tuesday as a few
locations see temperatures approach 90. The latter part of next
week appears cooler, with a trough moving in and the chance of a
few showers.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
Onshore flow continues behind a cold front that passed through
western WA last night/this morning. It has slowed and is
currently east of the Cascade Crest. Overhead there is a trough
remaining through Sunday as the low cuts off and begins to
pivot east. The remaining showers are moving east of I-5 this
afternoon, and will continue to trickle eastward through the
evening. Clouds are clearing west of I-5 on satellite this
afternoon, although much will still see cloud coverage going
into the evening (especially with any remnants of a convergence
zone that are able to persist). Winds will also remain breezy
through tonight for areas in the southwest interior/Pacific
Coast/Strait of Juan de Fuca coast as the onshore gradient
decreases tonight. Western WA will remain onshore through the
weekend, with cloud coverage filling back in Saturday morning,
and slowly scattering in the afternoon. Sunday is the sunnier of
the two weekend days with the trough splitting off.
Temperatures this weekend remain cool, with highs Saturday in
the low to mid 60s, and lows in the low to mid 40s. Sunday will
a see a slight increase of temperatures, with highs in the mid
60s to around 70.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
The ensembles remain in agreement that a ridge will build in
behind the departing trough Monday, and remain overhead through
early Wednesday. The ridge will amplify as it gets squished in
between the low to the east, and the trough over the Gulf of
Alaska. The flow will turn more offshore with winds becoming
light north/northeast at 5 to 15 mph. A thermal trough is also
expected to build along the coast under the ridge. The
combination of the ridge, offshore pattern, and thermal trough
will lead to a warm few days next week, with Tuesday being the
warmest of the forecast period. There remains a medium chance
that a few areas in the south sound/interior will see their
first 90 of the year with this pattern. A few metro Seattle
areas (particularly those away from the water), and areas south
of the city will see HeatRisk increase to moderate for the day
Tuesday (it will be minor before and after). It`s also important
to note that a lot of area lakes and rivers are still very
cold, with temperatures in the 50s to low 60s (for those
recreating near the waters). Lastly, the dry and offshore
pattern will result in dry relative humidity (RH) values. See
fire discussion below for further details. The remainder of the
week returns to onshore and cool as the low in the Gulf of
Alaska drifts south. There will also be a couple chances of
showers later in the week.
HPR
&&
.AVIATION...
Southwest flow aloft will continue tonight as a broad upper
level trough remains situated over the Gulf of Alaska. Onshore
flow continues in the low levels. Some light convergence showers
look to persist across the central Sound this afternoon, but
otherwise radar shows showers have largely pushed into the
Cascades. Expect overall shower activity to continue to taper
heading into the evening hours. Current conditions at the area
terminals have largely improved to MVFR across the central Sound
in shower activity and VFR elsewhere. A gradual lifting of ceilings
will continue into this evening, but areas of MVFR may linger
around any remaining convergence zone activity. Most areas
should improve to VFR by early evening. Another round of MVFR
ceilings will be possible for the interior terminals by early
Saturday, with latest guidance hinting at a 20-25 percent chance
of ceilings dropping to MVFR by 12Z.
KSEA...MVFR ceilings with light shower activity in the vicinity
of the terminal. MVFR ceilings may linger a bit longer with
convergence showers, but are expected to gradually lift towards
VFR through this evening hours as shower activity gradually
diminishes. Surface winds SE/E at 5-8 kt this afternoon and
will become more NE at 6-10 kt this evening. Ceilings look to
lower between 3000-4000 ft again overnight, with latest
probabilistic guidance indicating a 20-25 percent chance of
MVFR conditions developing at the terminal by 12Z.
14
&&
.MARINE...
Strong onshore flow will continue tonight with low pressure over
the interior of British Columbia and high pressure building offshore.
Gales will continue across the central and eastern Strait of Juan
de Fuca through tonight, with winds expected to ease late tonight
into early Saturday. Winds persisting at 15-25 kt across the coastal
waters will also ease by Saturday as high pressure starts to build
back into the area waters. Seas hovering between 10-12 ft across
the coastal waters will subside towards 7-9 ft tonight. Seas of
8-10 ft along the central Strait will also subside back to 4-6
ft by tonight. Another push of westerly winds is likely along
the central and eastern Strait Saturday afternoon and evening,
with latest HREF probabilities indicating roughly a 70-100
percent chance of wind gusts exceeding 21 kt.
High pressure over the waters will allow for onshore flow to
continue to ease over the weekend. Seas across the coastal
waters may become confused and steep at times between 6-8 feet
at 6-8 seconds under persistent northwesterly winds. Weak
offshore flow will then develop early next week as a thermal
trough develops near the coast. Offshore flow will be short-
lived, however, as additional systems look to move into the area
waters by midweek and bring the return of onshore flow.
14
&&
.FIRE WEATHER...
An upper level ridge will setup a drier, offshore pattern on
Monday and Tuesday, with maximum temperatures reaching into the
80s, and up to 90 in a few south sound/south interior locations.
Winds will generally remain light out of the northeast around
5-10 mph, but a few locations in the Cascades may see gusts up
to 20 mph from the east. The main concern will be a couple days
of drier relative humidity (RH) values, with values during the
day dipping to as low as 25 to 30 percent in the mentioned
areas. While fuels are not ready yet for red flag conditions, a
few dry and shrubby grassy areas, or dry piles of dead fuels
may be susceptible to fire starts, and/or rapid fire spread.
HPR
&&
.HYDROLOGY...
The daily hydrology discussion has ended until the start of the
next rainy season; it will only be updated during this time as
needed.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 11 PM PDT this evening for
Admiralty Inlet-Grays Harbor Bar-Northern Inland Waters
Including The San Juan Islands.
Small Craft Advisory until 3 AM PDT Saturday for West Entrance
U.S. Waters Strait Of Juan De Fuca.
Gale Warning until 11 PM PDT this evening for Central U.S.
Waters Strait Of Juan De Fuca-East Entrance U.S. Waters
Strait Of Juan De Fuca.
Small Craft Advisory from 11 PM this evening to 8 AM PDT
Saturday for Central U.S. Waters Strait Of Juan De Fuca-
East Entrance U.S. Waters Strait Of Juan De Fuca.
Small Craft Advisory until 5 AM PDT Saturday 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