Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
990
FXUS66 KSEW 230952
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
252 AM PDT Thu Apr 23 2026
.SYNOPSIS...
Upper level ridge offshore nosing into Northern British
Columbia combined with upper level low well to the east giving
Western Washington northerly flow aloft through the weekend. Air
mass unstable enough for a chance of late day showers over the
mountains Sunday and Monday. The upper level ridge will move
over Western Washington in the middle of next week.
&&
.SHORT TERM /TODAY THROUGH SATURDAY/...
Satellite imagery shows cloudy skies over most of Western
Washington this morning. Doppler radar still has a few showers
over the Cascades at 2 am/09z. With the cloud cover temperatures
were pretty uniform, mostly in the mid 40s to lower 50s.
Upper level ridge building into Northern British Columbia today
while an upper level low remains well to the east. End result
northerly flow aloft over the area. The forecast problem of the
day is when the moisture over Western Washington will dissipate.
While the northerly flow aloft is dry the flow in the lower
levels remains weakly onshore this morning. Not getting any
upper level ridging to provide some subsidence to help out with
the clearing. The layer is about 2500 feet thick with tops
5000-6000 feet. The low level flow does turn northerly this
afternoon. This plus the late April sunshine will slowly erode
the moisture layer over Western Washington this afternoon into
the evening hours. Cloudy skies for the most part this morning.
Highs in the mid 50s to lower 60s.
Skies clearing tonight. Lows in the mid 30s to lower 40s.
Dry northerly flow aloft with northerly flow in the lower levels
will give Western Washington plenty of sunshine Friday and
Saturday. Highs in the upper 50s to mid 60s. It will be a cool
night Friday night/Saturday morning. The potential is there for
another frost advisory for the Southwest Interior with lows
near freezing. For the remainder of the area lows in the mid
and upper 30s. Felton
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
Extended models in pretty good agreement with the upper level
low well to the east digging back to the west a little Sunday
and Monday pinching off the upper level ridge. North
northeasterly flow aloft still dry. Late day instablilty along
with weak upslope flow could produce a shower over the Cascades
in the late afternoon and evening hours both days. Upper level
low weakens and moves east Tuesday and Wednesday allowing the
upper level ridge offshore to move into the area. Low level flow
never turns offshore through the entire period. This will keep
highs mostly in the 60s with lower 70s possible as the ridge
axis moves overhead Wednesday. Lows upper 30s to mid 40s.
&&
.AVIATION...
Ceilings are slowly improving across the area early this morning,
with most locations now at low-end VFR, through areas of MVFR
persist across the northern interior terminals. MVFR will likely
persist through much of the day and into the early afternoon in this
area as weak low-level convergence continues to persist. However,
all clouds should begin to clear out between 22Z Thu - 03Z Fri.
Areas of fog may then begin to develop around/after 12Z Fri in the
valleys. Southerly winds around 5 to 10 kt will slowly ease this
morning, becoming mostly light westerly after 21Z, then northwest to
north after 00Z Mon.
KSEA...Ceilings have lifted to VFR and have begun to break apart
early this morning. Low-end VFR to upper-end MVFR cigs will continue
to persist over the terminal through around 00Z Fri when clouds will
begin to scatter. Best chances for additional lower cigs will be 15-
20Z this morning (25-35% chance MVFR cigs). South winds 8 to 12 kt
will decrease after 18Z as winds become more westerly around 21Z
then north after 00Z Friday. There will be a 15-20% of low
stratus or fog development after 12Z Friday.
62
&&
.MARINE...
The overall weather pattern looks to remain fairly static over the
next week. Broad high pressure over the northeast Pacific will
remain offshore and get pushed out as lower pressure remains in
place over the inland Pacific Northwest. Winds may be a bit
breezy, mainly over the interior waters and the gaps in the
coastal terrain, on Friday as winds turn north to northeasterly.
Lighter onshore flow resumes Sunday into early next week. Seas
currently 10 to 12 ft will continue to ease this morning to
below 10 ft by this afternoon, with seas remaining 5 to 8 ft
through the remainder of the forecast period.
62
&&
.HYDROLOGY...
No river flooding the next 7 days.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 11 AM PDT this morning 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-Grays Harbor Bar.
&&
$$
NWS SEW Office Area Forecast Discussion