Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
784
FXUS66 KSEW 312050
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
150 PM PDT Sun May 31 2026
.SYNOPSIS...An upper level ridge will gradually build across the
Pacific Northwest early this week, resulting in warming
temperatures through Tuesday. Temperatures will peak on Tuesday,
resulting in Minor to Moderate HeatRisk. Onshore flow increases
Wednesday as the upper ridge weakens. The next disturbance
approaches Western Washington later in the week.
&&
.SHORT TERM /TONIGHT THROUGH TUESDAY/...Mainly sunny conditions
this afternoon as high pressure builds into the Pacific
Northwest. High temperatures today will peak in the 60s to low
70s. Upper ridging continues to gradually build over the region
on Monday with temperatures warming further into the 70s and low
80s by Monday afternoon.
Light offshore flow late Monday into Tuesday with a weak surface
thermal trough developing early this week. Temperatures will
peak on Tuesday with the upper level ridge axis overhead.
Temperatures Tuesday afternoon will reach the 80s for most
lowland areas, with the potential for highs in the low 90s
across portions of Lewis, Mason, Thurston, and Grays Harbor
Counties. These temperatures correspond to widespread Minor
HeatRisk, as well as a 50-80% probability for Moderate HeatRisk
from Everett southwards across Puget Sound and towards the
Chehalis Valley. If you`re heading out on the water, always wear a
life jacket and take precautions as lakes and rivers continue to
run cold.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...Onshore flow
increases by Wednesday as the upper ridge axis slides eastwards
and the ridge flattens over Western Washington. This will result
in increasing clouds Wednesday, as well as cooler temperatures,
with highs back into the 60s and 70s. Of note, there is a
slight uptick in precipitation potential Wednesday afternoon
into the evening across the Cascades as a weakening upper low
approaches Western Washington. NBM probability for thunderstorms
on Wednesday afternoon ranges 10 to 20% at this time over the
Cascades.
Onshore flow continues on Thursday with a continued cooling
trend, with current forecast highs dropping back into the 60s to
low 70s. Light precipitation or drizzle also can`t be ruled out
on Thursday as well. Ensembles are consistent that deep
troughing approaches the Pacific Northwest from the NE Pacific
Friday into next weekend. Unsettled conditions, including
precipitation chances, clouds, and cooler temperatures are
expected by next weekend with the troughing across the area. JD
&&
.AVIATION...Northerly flow aloft continues into Monday as an
upper ridge continues to build offshore. VFR conditions prevail
through the TAF period with mostly clear skies. High clouds will
increase Monday afternoon. N/NW surface winds of 5 to 10 kts
into this evening will become light NE for most sites tonight.
N/NW surface winds increase again on Monday.
KSEA...VFR conditions through the TAF period with increasing
high clouds Monday afternoon. N/NW surface winds ranging 7 to 12
kts transitioning more NE around 5 to 9 kts tonight. JD
&&
.MARINE...High pressure continues to build across the waters
today with Northwest flow prevailing over the Coastal Waters
into tonight. Northwest winds will briefly be enhanced this
evening over the Coastal Waters, with sustained winds ranging 15
to 20 kts and gusts to 25 kt. In addition, increasing west
winds are expected through the Strait of Juan de Fuca this
evening. Winds are forecast to primarily remain below SCA
thresholds, however, brief gusts to 21 kts are possible.
Winds will become lighter Monday into Tuesday as a weak thermal
trough develops along the coast, briefly turning winds offshore
Monday night into early Tuesday. Onshore flow resumes late
Tuesday as the thermal trough is shifted eastwards. Onshore flow
will further strengthen Wednesday and through the rest of the
weak as weak disturbances move across the waters. Small Craft
Advisory winds are likely for an extended period beginning
Wednesday through late in the week in the Strait of Juan de Fuca.
There also remains a 30 to 60 percent chance of gales through
the central and eastern Strait Thursday evening.
Seas will build to 6 to 10 feet for a brief period later today
into tonight. Seas will be steep during this time with a
dominant period of 6 to 7 seconds. Seas will fall back to 4 to 6
feet Monday and Tuesday. Seas will generally remain 4 to 6 feet
through late week, building to 8 feet at times. JD
&&
.FIRE WEATHER...An upper ridge will setup a dry, warm pattern on
Monday and Tuesday. Maximum temperatures will reach the 80s
(with low 90s in localized areas) on Tuesday. A weak thermal
trough will build north over the region, which results in light
offshore developing late Monday into Tuesday. Winds will be
rather light during this period, however, a few gusts ranging 15
to 20 MPH will remain possible over the Cascades. Minimum RHs
will approach critical thresholds on Tuesday with the light
offshore flow, with RHs dropping into the 20% range mainly from
King County southwards, and into the Cascade Valleys. However,
this stretch will be short-lived as onshore flow resumes
Wednesday resulting in higher humidities the second half of the
week.
&&
.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 from 2 PM this afternoon to 2 AM PDT
Monday 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