Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
014
FXUS66 KSEW 301024
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
324 AM PDT Sun Aug 30 2026
.SYNOPSIS...
Upper level ridge over the area today with a weak system moving
into Southern British Columbia. Ridge builds tonight before
moving east Monday. Weak warm front moving into the area Tuesday
night followed by a strong for September cold front Wednesday
into Wednesday night. Upper level low associated with the front
remaining in the vicinity Thursday and Friday. The low will
move out of the area Saturday.
&&
.SHORT TERM /TODAY THROUGH TUESDAY/...
Satellite imagery shows mostly cloudy skies over Western
Washington early this morning with some breaks in the cloud
cover over the South Puget Sound and along the Strait of Juan de
Fuca. Temperatures at 3 am/10z were in the mid to upper 40s
where there are breaks in the clouds and in the 50s elsewhere.
Flat upper ridge over the area today. Weak system moving into
Southern British Columbia will give locations near the Canadian
border a slight chance of showers this morning. Between the
cloud cover this morning and increasing middle and high level
clouds from the system moving by to the north mostly cloudy day
in store. Highs in the 60s and lower 70s.
Upper level ridge building tonight in response to a digging
trough offshore. Cloud cover decreasing overnight. Longer nights
plus some low level moisture from Saturday leading to patchy to
areas of fog in the fog prone locations after midnight. Cool
morning with lows in the mid 40s to mid 50s.
Upper level ridge moving east Monday. Marine layer remaining
west of Puget Sound in the morning retreating to the coastline
in the afternoon. Under mostly sunny skies highs getting back to
near normal, in the mid 60s to mid 70s.
Western Washington on the backside of the upper level ridge
Monday night. Increasing middle and high clouds Tuesday as the
warm front associated with a deep upper level low moving out of
the Gulf of Alaska. Could see some sprinkles west of the Sound
Tuesday afternoon. Highs in the mid 60s to lower 70s.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
Weak warm front Tuesday night for a chance of rain over the
area. Model solutions becoming inconsistent again with the
current run. The models are having a hard time with the track
of the upper level low. Current run has a more north south track
off the coast which will slow down the arrival of the front
into Western Washington with the cold frontal passage Wednesday
night. A little slower than previous runs. Windy conditions
developing along the coast and over the Northwest Interior.
While the winds speeds might not get up to advisory category
with plenty of foliage plus trees not in great shape after a dry
summer there could be more impacts with this system versus a
similar one a month or so later.
Model inconsistencies continue Thursday and Friday with the GFS
taking the low far enough to the south to keep more
precipitation out of the forecast. The ECMWF parks the low off
the coast with a couple of impulses spinning out of the low
moving through the area. Ensemble solutions favor the ECMWF
solution Thursday and lean towards the GFS Friday. Confidence
low at this point with a lack of consensus in multiple model
runs. Will go chance to likely pops Thursday with chance to
slight chance pops Friday.
Differences continue Saturday with the ECMWF kicking the low out
to the northeast while the GFS sinks the low south. Saturday has
the best chance of being a dry day in the extended. For now will
keep some slight chance pops in the forecast.
Cool Wednesday and Thursday with highs in the lower to mid 60s.
A little warmer Friday and Saturday with highs in the mid 60s to
lower 70s. Lows in the upper 40s and 50s. Felton
&&
.AVIATION...
An upper level low will move east into Rockies today as flow aloft
transitions to northwesterly. Satellite shows significant stratus
development across the Kitsap and interior Puget Sound this morning
(ahead of model guidance), with cameras across Seattle indicating
the stratus is likely at the lower-end of MVFR. Latest 09Z TAF
updates has reflected a lower-end MVFR broken deck going into the
morning for most interior terminals (as well as some IFR for more
sheltered areas in the Kitsap/South Interior) based on current
observations and probabilities (likely aided by recent rains in the
area). The overall threat for widespread IFR ranges from 10-30% this
morning across these areas, with visibility probabilities remaining
lower. Lift time to VFR will take place from 18-21Z, though lower
VFR decks may remain longer into the afternoon for northern
locations. Early indications for Monday is increased areas of
IFR/LIFR stratus and/or fog (especially at sheltered terminals).
Southwest winds this morning at 5-10 kt will shift to the northwest
this evening, dropping to 5 kt or less.
KSEA...MVFR stratus has filled in over the terminal a bit early.
Given the extra low level moisture from recent rains, the 09Z TAF
included a lower-end MVFR deck going into the 12Z-18Z period. The
stratus will continue to fill in this morning, and there remains a
15% chance for brief IFR ceilings and/or visibilities during the 12-
18Z window. VFR improvement will take place 18-21Z. Southwest winds
4-8 kt will switch to the north around 00Z, decreasing to 5 kt or
less tonight. Monday morning will present vicinity fog/low stratus
near the terminal, but uncertainty remains on a track into the
terminal in the morning.
HPR
&&
.MARINE...
A trough will move out of the region and into the Rockies today,
with additional systems bypassing the waters to the north Monday and
Tuesday. Winds and waves across the waters will likely remain
benign, although the light winds and combination of low level
moisture from recent rains may lead to pockets of fog forming Monday
morning across the coastal waters and west Strait of Juan de Fuca.
Models remain persistent that a stronger low pressure system will
move in Tuesday night, lasting into Thursday, bringing fall-like
conditions across the waters. Probabilities for gusts up to gale
force for portions of the southern coastal waters and east Strait of
Juan de Fuca remain at 60-70%. Once the system moves out, winds will
become light out of the north and west going into next weekend.
Seas at 3-6 ft through midweek, then increasing to 8-11 ft around
Wednesday through Thursday, before dropping back to 4-6 ft next
weekend.
HPR
&&
.FIRE WEATHER...
Cooler weather with good relative humidity recoveries overnight
through Tuesday easing fire weather concerns over the area.
Strong for the first week of September system arriving
Wednesday will bring abundant rainfall to the coast and
Olympics. Two to three inches of rain are forecast in the
Olympics, one to one and a half inches for the coast. For the
interior and the Cascades a half inch to an inch is in the
forecast through Thursday morning. This is good news for the
fires still burning from the Cascade crest westward. Weather
remaining cool through the end of the week with chances of
additional precipitation keeping fire weather concerns in check.
Felton
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...None.
&&
$$
NWS SEW Office Area Forecast Discussion