Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
096
FXUS66 KSEW 140311
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
811 PM PDT Sat Jun 13 2026
.SYNOPSIS...
A dry and warm airmass associated with a strong upper level ridge
will settle over western Washington this weekend through
Monday. Temperatures peaking in the 80s and 90s will bring
widespread Moderate HeatRisk to the region on Sunday and Monday.
Offshore flow will bring lower relative humidities and elevated
fire danger. The ridge will weaken on Tuesday, resulting in
increased onshore flow and cooler temperatures through the rest
of the week.
&&
.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...
Forecast trends remain on track this evening. The axis of thermally
induced low pressure remains oriented along the coast as evidenced
by the record high of 82 at Hoquiam today which broke a record that
had been in place for 65 years. The thermal trough will gradually
shift inland late Sunday with cooler conditions for the coast on
Monday. Two more very warm days await interior areas before the
Pacific AC system kicks in to cool us down. Previous discussion
follows with updates to aviation portion. 27
The short term forecast is highlighted by hot and dry conditions
with clear skies and widespread high temperatures in the 80s and 90s
across the interior lowlands of western Washington on Sunday and
Monday. The very warm and dry airmass in place is in response to a
highly amplified upper level ridge over the coastal waters that will
begin moving inland late Sunday. The LREF ensemble mean continues to
show 500 mb heights peaking near 588-589 dam Sunday night into
Monday, which is near the climatological 98-99th percentile for this
time of year. As a result, several daily record high temperatures
are likely with widespread Moderate HeatRisk. Please refer to the
climate section below if interested in details regarding potential
records that may be broken.
The forecast remains on track with Sunday and Monday still
shaping up to be the hottest days of the week as a thermally
induced surface trough settles over the region. In addition to
warm daytime temperatures well into the 80s and 90s, poor
overnight relief is expected as low temperatures will only
decrease into the upper 50s to low 60s for a brief period of
time shortly before sunrise. In fact, there is a 10-30% chance
urban areas to the south and east of the Puget Sound will see
overnight lows at or above 65 degrees Sunday night and Monday
night, particularly from Olympia to Tacoma to Kent to Seattle.
Poor overnight relief will increase the risk of heat-related
illnesses for populations that are vulnerable to heat and do not
have access to air conditioning. Populations who may be
vulnerable to heat include newborns, children under age four,
the elderly, those with chronic medical conditions, and
pregnant people.
In addition the heat, breezy northerly winds are expected
across the Puget Sound this afternoon/evening with gusts
reaching 15-20 mph as the aforementioned thermal trough shifts
in from the south, with periods of offshore flow expected across
the foothills and Cascades. Offshore flow will increase late
Saturday night/Sunday morning across the southern Cascades and
foothills, with gusts 15-20 mph funneling through the gaps.
Another round of breezy winds are expected Sunday afternoon
across the Puget Sound.
-23
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
The long term forecast is highlighted by a return to onshore
flow with relatively cooler temperatures closer to seasonal
normals. On Tuesday, WPC`s cluster analysis continue to suggest
the ridge over the region will flatten out, bringing near zonal
flow to the area. Near zonal to northwesterly flow aloft is then
favored to persist through next Saturday. This will maintain
fairly consistent temperatures each day, with highs generally
ranging from the mid 70s to lower 80s over the lowlands, except
60s at the coast. Chances for precipitation are less than 10%
each day, suggesting confidence is high the ongoing dry weather
pattern will continue. -23
&&
.AVIATION...
Northwest flow aloft continues into Sunday as upper ridge axis just
offshore gradually shifts toward the coast. Low level offshore flow
continues near the surface and will transition to light onshore
Sunday evening. VFR prevails.
KSEA...VFR. Surface winds northerly 7 to 10 knots this evening will
ease to northeasterly 4 to 7 knots overnight then rise to N/NW 7 to
10 knots again Sunday afternoon.
27
&&
.MARINE...
Expansive surface high pressure centered offshore will persist
through early next week. A thermal trough will build over
western Oregon and shift into the interior of western
Washington starting Sunday night. This will induce onshore flow
for the interior coastal waters starting Sunday night into Monday.
Onshore pushes likely occur for the Strait of Juan de Fuca Monday
through Wednesday, with potential for gales on Monday and Tuesday.
Chances for gale force wind gusts over 34 kt peak Tuesday
afternoon/evening at 80-90% over the Strait of Juan de Fuca.
Coastal seas will remain well under 10 feet through the weekend
before building to around 10 feet by late Tuesday. Higher swells
to around 12 ft are possible Wednesday. -23
&&
.FIRE WEATHER...
Abnormally warm and dry conditions over the next few days will
bring elevated fire weather concerns through Monday. An upper
level ridge over the area this weekend with low level flow
turning offshore Saturday night. Widespread high temperatures in
the 80s and 90s are expected Sunday and Monday, with low
relative humidity values, especially over the southwest
Interior where humidities may drop into the teens both Sunday
and Monday afternoon. Even though fine fuels have not reached
critical thresholds, this rapid drying will create elevated fire
concerns especially for dry grassy/shrubby areas, as well as
piles of dead fuels. Offshore flow Sunday into Monday will
prevent good relative humidity recoveries overnight. Relative
humidities will improve with the return of onshore flow Tuesday.
Low level onshore flow and cooler temperatures throughout the
week will ease fire weather concerns.
&&
.CLIMATE...
SeaTac is forecast to reach 87-89 degrees on Sunday, June 14,
which would break the current record of 86 degrees set back in
1988. NBM probabilities for highs of 90 degrees or warmer at
SeaTac on Sunday are at 5%. SeaTac is forecast to reach 90-92
degrees on Monday, June 15, which would break the current record
of 88 degrees set back in 1963. While it is not the most likely
outcome, two consecutive days of 90 degrees or warmer cannot be
completed ruled out. This is very rare at SeaTac during the
first half of June; the last time that occurred is June 6-7,
2003.
Olympia is also likely to break record high temperatures on
Sunday, June 14 and Monday, June 15. Forecast highs on both
days are currently at 94 degrees. This would break two daily
record highs, as the current record high for June 14 is 88
degrees set back in 1999, and the current record high for June
15 is 88 degrees set back in 1963.
Even Hoquiam is likely to break a record high temperature on
Sunday, June 14. The current forecast suggests Hoquiam will peak
near 86 degrees on Sunday, which would break the current record
high of 79 degrees set back in 1988.
-23
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Heat Advisory from 11 AM Sunday to 5 AM PDT Tuesday for City
of Seattle-Downtown Everett / Marysville Area-Eastern
Kitsap County-Eastern Strait of Juan de Fuca-Eastside-
Foothills and Valleys of Central King County-Foothills
and Valleys of Pierce and Southern King Counties-
Foothills and Valleys of Snohomish and Northern King
Counties-Foothills and Valleys of Thurston and Lewis
Counties-Foothills and Valleys of the North Cascades-
Foothills of the Western and Southern Olympic Peninsula-
Island County-Lake Crescent Area Including US 101-Lower
Chehalis River Valley-Lowlands of Lewis and Southern
Thurston Counties-Lowlands of Pierce and Southern King
Counties-Lowlands of Western Skagit and Northwestern
Snohomish Counties-Lowlands of Western Whatcom County-
Middle Chehalis River Valley-Northern Hood Canal-Olympia
and Southern Puget Sound-Port Townsend Area-San Juan
County-Shoreline / Lynnwood / South Everett Area-Southern
Hood Canal-Willapa and Black Hills.
PZ...None.
&&
$$
NWS SEW Office Area Forecast Discussion