Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
450
FXUS66 KSEW 020259
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
759 PM PDT Wed Jul 1 2026
.SYNOPSIS...Cool and cloudy conditions will continue through
Friday as onshore flow persists. A weakening cool front will
bring chances for light rains to the coastal and mountain
regions Thursday with only slight chances across the lowlands.
Improving conditions are expected Friday afternoon through the
weekend with decreasing cloud cover and temperatures returning
to near normal. Dry weather and seasonable temperatures will
continue into early next week.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...Previous
discussion...Considerable cloud cover persists early this
afternoon across much of Western WA, though clearing has begin
pushing into the coastal regions. Patchy breaks in the clouds
have allowed for some filtered sunshine across the lowlands with
temperatures climbing into the 60s as of 1pm. Continued mostly
cloudy skies with a few spotty breaks in the cloud deck are
likely through the remainder of the afternoon and early evening
before clouds redevelop overnight.
On Thursday, a shortwave pushing into British Columbia will drag
a weakening cool front into Western WA, with light rain chances
spreading into the coast and mountain terrain during the day,
and just slight chances (20% or less) across the Seattle urban
corridor. Otherwise, continued cloudy and cool conditions are
expected.
By Friday, heights will begin to climb considerably as ridging
builds into the central and western US. This will allow for an
earlier afternoon clearing trend and encourage afternoon highs
to climb closer to seasonal normals.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...Increasing heights
over the weekend in response to strengthening ridging in the
Western and Central US will allow for temperatures to return to
near normal early July values. Meanwhile, morning stratus across
the low-lands will tend to thin and be less persistent than
observed over the past week. Dry conditions and continued
seasonable temperatures will continue into early next week.
&&
.AVIATION...Northwesterly flow from an upper level trough over
the western US will continue through the TAF period. VFR
conditions in place over much of W WA this evening, although
marine stratus resulting in MVFR conditions along the coast,
including HQM. These stratus will once again push inland
overnight, resulting in terminals as far east as OLM seeing MVFR
conditions by early Thursday morning. Models hesitant to bring
these lower clouds into the eastern terminals. Some models
starting to show the prospect of this occurring, though timing
and chances are limited. Opted to include this prospect as TEMPO
groups until models present a more convincing argument. Cigs
lift back into VFR most locations by noon Thursday. A weak
passing front may allow for scattered showers, with best chances
being northern and western terminals. Opted for VCSH for
impacted locations, but given weak model output, this may be
overdone. South to southwest winds 5 to 10 kt will continue
through the period, with a few gusts of 15 to 20 knots possible
this afternoon.
KSEA...VFR conditions this evening into tonight. Cigs lowering to at
least low-end VFR conditions overnight. MVFR conditions possible by
12Z, but models are not terribly convincing of this outcome at this
time. As such, have allowed for TEMPO groups and should output be
more convincing, can upgrade these into dominant wx feature with 03Z
or 06Z updates. Cigs lift by 19Z back into VFR conditions. Prospect
for scattered showers Thursday, but confidence is not there for them
getting as far south as the terminal at this time, hence no
inclusion. South to southwesterly winds to persist at speeds ranging
5-10 kts...with the higher end of that range expected Thursday
afternoon.
18
&&
.MARINE...Broad high pressure offshore and low pressure inland
will continue, maintaining onshore flow. A frontal system will
cross area waters on Thursday, weakening the onshore flow
somewhat. Thereafter, a deepening low pressure system over the
Gulf of Alaska will allow onshore flow to persist and strengthen
somewhat over the Pacific Northwest. This will result in
periods of diurnally driven westerly pushes through the Strait
of Juan de Fuca over the next week.
A westerly push this evening through the Strait of Juan de Fuca will
generate Small Craft winds through the central and east Strait. A
frontal system Thursday will limit winds over area waters on
Thursday. Additional westerly pushes are favored to occur Friday and
Saturday evenings, and likely once again on Monday and Tuesday. A
weak frontal system will also bring gusty winds to the southern
coastal waters Sunday, with potential for SCA winds (60-70% chance
of gusts over 30 kt).
Seas easing to 4-6 ft tonight, lowering slightly to 3 to 5 feet on
Thursday before gradually building to 6 to 9 feet on Sunday and
Monday. Seas slowly subside on Tuesday.
15/18
&&
.FIRE WEATHER...Little in the way of fire weather concerns in
the week ahead. Upper level troughing maintaining cool and
cloudy conditions with high relative humidity values and a
slight chance for showers along the coast and mountains on
Thursday. Drier, sunnier, and more seasonable temperatures will
begin Friday continuing into early next week. Low level onshore
flow will moderate daytime minimum RH values and bring in good
RH recovery each night.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 2 AM PDT Thursday for Central U.S.
Waters Strait Of Juan De Fuca-East Entrance U.S. Waters
Strait Of Juan De Fuca.
&&
$$
NWS SEW Office Area Forecast Discussion