Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
785
FXUS66 KSEW 290828
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
128 AM PDT Mon Jun 29 2026
.SYNOPSIS...
A broad upper level trough will continue to produce unsettled
and cool conditions across Western Washington into midweek along
with chances for mainly mountain showers. Drier conditions and
a modest warming trend are expected for the upcoming holiday
weekend with a weak ridge of high pressure aloft.
&&
.SHORT TERM /TODAY THROUGH WEDNESDAY/...
Western Washington remains under the influence of broad upper
troughing aloft and low level onshore flow. At the risk of
sounding like a broken record, the forecast into midweek will
largely mimic what we saw yesterday. Night and morning low
clouds will stubbornly give way to a few peeks of late day sun
over the interior lowlands and temperatures will be held several
degrees below seasonal averages. A series of weak disturbances
moving through the trough will occasionally kick off a shower
over the higher terrain or squeeze out some coastal drizzle, but
otherwise mainly dry conditions will prevail.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
The long term forecast period begins with much the same trend of
cool unsettled conditions. A few of the operational model runs
attempt to bring a weakening frontal system into the area on
Thursday, but it may well encounter a building ridge offshore
and result in little if any precipitation away from the coast
and Olympic Peninsula.
As we move toward the upcoming holiday weekend, ensembles are
continuing the trend of previous runs which have upper
troughing retreating into the northern Gulf of Alaska and at
least some upper ridging rebuilding into the Pacific Northwest.
There`s still a decent spread in solutions with regard to the
strength of the ridging, but the overall ensemble averages
suggest a return to temperatures near, if not a little above,
seasonal norms for early July along with dry conditions.
27
&&
.AVIATION...
Broad upper troughing over the interior West and an upper ridge
centered well offshore will continue to produce north to
northwest flow aloft over Western Washington. The low level flow
remains onshore with widespread low level moisture intruding
across the interior lowlands this morning. Widespread low MVFR
and areas of IFR ceilings are expected through 18Z. Gradual
improvement to low end VFR is expected near or after 21Z with
MVFR ceilings continuing for coastal areas. Ceilings will
deteriorate back to low MVFR or localized IFR once again
tonight.
KSEA...Low MVFR ceilings are expected to persist into midday
before gradually lifting to low end VFR thresholds after around
21Z. Ceilings will fall back to MVFR late tonight. Surface winds
south to southwesterly 7 to 10 knots rising to 9 to 12 knots
later this evening.
27
&&
.MARINE...
A broad surface ridge centered well offshore and lower pressure
across the interior will remain the dominant weather pattern
into midweek. This will maintain onshore flow with gusty
northwesterlies and steep seas for the coastal waters. Diurnally
driven westerly pushes will occur in the Strait of Juan de Fuca
as well. The offshore ridge is expected to weaken during the
later half of the week as a broad surface low approaches the
central British Columbia coast. This will weaken onshore flow
allowing winds over the coastal waters to ease and seas subside.
27
&&
.FIRE WEATHER...
Little in the way of fire weather concerns remain in the
picture into the week ahead with upper troughing maintaining
cool conditions, high RH, and periodic chances for shower
activity. A trend toward more seasonable temperatures is
indicated toward late week, but a significant warm and dry spell
is not expected in the next 7 days.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 1 AM PDT early this morning for
Central U.S. Waters Strait Of Juan De Fuca-East Entrance
U.S. Waters Strait Of Juan De Fuca.
Small Craft Advisory from 5 PM this afternoon to 2 AM PDT
Tuesday 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 PM PDT Tuesday 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