Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
800
FXUS66 KSEW 132246
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
346 PM PDT Mon Jul 13 2026
.SYNOPSIS...High pressure aloft will rebuild across the region
into Wednesday for warm and drier conditions. An area of low
pressure may bring a threat of showers and thunderstorms around
Thursday before high pressure regains control over the weekend
for a return of dry conditions and well above normal
temperatures.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...Mostly clear
conditions this afternoon across Western Washington with
localized stratus along the coast. High pressure will continue
to build over the region as an area of low pressure dives
southwards well offshore. Dry, warm conditions continue for the
majority of the area through Wednesday. Temperatures will warm
into the 80s for much of the interior Tuesday into Wednesday,
resulting in continued Minor HeatRisk and areas of Moderate
HeatRisk. Although POPs remain very low on Wednesday afternoon,
will need to monitor the threat for convection over the
Cascades with increasing instability. Otherwise, haze aloft will
be around into midweek with continued southerly flow.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...Uncertainty increases in
ensembles for Thursday into Friday as the upper low located
offshore meanders closer to the Pacific Northwest. However,
there has been an uptick in POPs for the Thursday period on the
NBM. Looking at Cluster Analysis, ECMWF/CMC ensembles generally
bring the upper low track closer to W WA by Thursday, with the
GEFS maintaining more of an offshore solution (more ridging over
W WA). Dependent on the track, there is a threat for showers and
thunderstorms during this period with more S/SE flow aloft.
Given the potential in elevated instability, convection could
occur during the overnight and morning periods as well, from
late Wednesday night into early Friday. This will need to be
monitored closely as this would pose a fire weather concern, as
well as impact any outdoor events.
Upper level ridging is then expected to build next weekend into
early next week, resulting in the return of dry conditions and
warming temperatures. The threat for Moderate HeatRisk increases
early next week, with widespread probabilities of 50% or greater
for Moderate HeatRisk.
&&
.AVIATION...Southwesterly flow aloft continues into Tuesday as
high pressure remains over the region with a area of low
pressure offshore. VFR conditions at all area terminals this
afternoon will continue into the overnight hours as conditions
remain stable. Winds generally from the N/NE this afternoon,
with some variances to the NW as well. Speeds remain around 8 to
12 knots and will decrease overnight, turning more variable
into Tuesday morning.
KSEA...VFR conditions throughout the forecast period. N/NE
winds this afternoon around 5 to 10 knots. Winds will decrease
into the overnight hours, and will remain N/NE with speeds
around 3 to 6 knots. VFR will continue into Tuesday morning.
Mazurkiewicz
&&
.MARINE...Surface high pressure will remain over the coastal
waters throughout the next couple of days. Diurnally driven
westerly pushes down the Strait of Juan De Fuca will continue,
with a Small Craft Advisory out for this evenings push. The
coastal waters may see a few wind gusts up to 20 kts on Thursday
and Friday as a low pressure system tracks through the waters,
but confidence is low at this time.
Coastal seas remain at 4 to 6 feet through midweek, with seas
slightly increasing to 7 to 8 feet with periods of 6 to 8
seconds.
Mazurkiewicz
&&
.FIRE WEATHER...Warming temperatures are on track through the middle
of the week, with minimum relative humidity values dipping into the
upper 20 to low 30 percent range throughout western Washington. A
bit of a change is possible by midweek as thunderstorms get
reintroduced into the forecast for Thursday. While this forecast is
still highly variable, the potential for new ignitions on dry fuels
due to lightning strikes is of notable concern. Less is known about
exact rain amounts and whether these storms will contain wetting
rains, but these details will become more available over the next
few forecast cycles. It`s important to note that even if
thunderstorms do not occur, elevated fire weather conditions are
likely to persist due to the warmer and drier weather that is
forecast to continue well into the weekend.
21
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory from 5 PM this afternoon to 1 AM PDT
Tuesday 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