Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
695
FXUS66 KSEW 311602
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
902 AM PDT Sun May 31 2026
.SYNOPSIS...Upper level high pressure will continue to
gradually build across the Pacific Northwest, resulting in
gradually warming temperatures through the early part of this
week. Temperatures will peak on Tuesday, resulting in Minor to
Moderate HeatRisk. Onshore flow will increase Wednesday as the
upper ridge weakens, followed by the next disturbance
approaching Western Washington late this week.
&&
.SHORT TERM /TODAY THROUGH TUESDAY/...Patchy clouds across
Western Washington this morning, otherwise mostly sunny
conditions early today. Clear skies this afternoon from a
building upper level ridge offshore will allow temperatures to
rise up to the mid 60s to low 70s today.
Temperatures will warm successively each day, being enhanced by light
offshore flow developing from a weak surface thermal trough. Highs
on Monday will rise into the 70s to near 80 on Monday. Tuesday will
be the warmest day as the upper level ridge axis moves overhead over
the region and the surface thermal trough moves inland. With high
temperatures in the upper 70s to near 90, as well as lows in the mid
to upper 50, this corresponds to Minor (Yellow) HeatRisk for the
coastal areas and northern interior locations, as well as 50-60%
chance of reaching Moderate (Orange) HeatRisk through the Chehalis
Valley, South Sound, interior portions of southwest Washington, and
areas of the Seattle Metro away from the water.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...Ensemble guidance
continues to remain consistent for the midweek period with a
flattening upper ridge and the thermal low pressure sliding
eastward. This will bring a return of onshore flow at the lower
levels Wednesday and Thursday, with temperatures returning
closer to seasonal normals and relative humidities increase. The
next disturbance then is likely to move into the region late
the week, bringing a return of increasing clouds and a return of
precipitation toward next weekend.
&&
.AVIATION...West to northwesterly flow continues aloft as an upper
level ridge builds offshore today. VFR conditions prevail through
the TAF period with mostly clear skies. Light north/northwest winds
will increase during the day to 8-15 kt, decreasing to around 5 to
10 kt tonight and becoming more northeast/easterly.
KSEA...VFR conditions prevail through the TAF period. NE winds 8-12
kt early this morning becoming NW 10-15 kt during the day,
transitioning back to NE tonight.
62/21
&&
.MARINE...High pressure will build into this evening, allowing
northwest winds over the coastal waters to bump up to 15-20 kt
with gusts up to 25 kt later today. This will also allow seas to
build up to around 6-8 ft, and they will be steep with a
dominant period of around 6 to 7 seconds. This will ease early
Monday morning as winds also ease accordingly.
Conditions become more tranquil Monday into Tuesday as high pressure
weakens and is replaced by weak thermal troughing along the coast,
which may briefly turn winds more offshore early Monday, and then
again Monday night into early Tuesday. Onshore flow will resume
during the day on Tuesday as the thermal trough is forced eastward.
Onshore flow will become stronger Wednesday and through the rest of
the week as weak disturbances move across the coastal waters. An
extended period of SCA conditions is expected through the strait,
with the best chance of gale force winds being Thursday
afternoon and evening.
Seas 5 to 6 ft today will increase to 6 to 8 ft with a dominant
period of around 6 or 7 seconds tonight into early Monday. Seas fall
Monday back to around 4 to 6 ft and remain around there through the
week.
JD/62
&&
.FIRE WEATHER...An upper level ridge will setup a drier pattern
on Monday and Tuesday, with maximum temperatures reaching into
the 80s (with a few spots touching 90). Expect a weak thermal
trough to build north over the region, with some light offshore
flow developing as a result. Winds appear to remain rather
light, but a few gusts to 15 mph near the Cascades remain
possible. This will help to bring drier conditions in to the
area with daytime RHs down approaching critical thresholds. This
stretch appears short-lived, with a resumption of onshore flow
bringing higher humidities for 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