Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
236
FXUS66 KSEW 131040
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
340 AM 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 /TODAY THROUGH MONDAY/...
An upper level ridge will maintain a dry and very warm airmass over
Western Washington through Monday. Currently the upper level ridge
axis sits over British Columbia. Latest satellite imagery has
Washington under clear skies with temperatures in the mid to upper
50s. A sunny day is in store today across the region. High
temperatures will reach the upper 70s to 80s. The ridge axis will
move inland on Sunday and remain situated over the region through
Monday. The forecast remains on track with Sunday and Monday being
the hottest days as a thermal trough settles over the region.
Temperatures are expected to peak into the mid 80s to 90s. As a
result, widespread Moderate HeatRisk is expected across the
region. In addition to warm daytime temperatures, little
overnight relief is expected as low temperatures will only
decrease into the upper 50s to low 60s.
Breezy northerly winds are expected across Puget Sound this
afternoon/evening with gusts reaching 15-20 mph, with periods of
offshore flow 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 expected Sunday afternoon across
Puget Sound.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Overnight temperatures Monday night into Tuesday morning will be on
the warm side as well, with low temperatures in the upper 50s to low
60s. The upper level ridge will begin to flatten late Monday night.
Long term guidance suggests a zonal pattern is favored to develop
over Western Washington, promoting an onshore flow and cooler
temperatures with highs in the 60s along the coast and upper 70s to
low 80s in the interior through the rest of the week.
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&&
.AVIATION...
Dry conditions and VFR ceilings prevail through the TAF forecast
period due to high pressure centered offshore. Expect light
northerly winds around 5 kts this morning, increasing to around
10 kts during peak diurnal heating this afternoon and evening.
Gusts to 15 kts possible, especially in and around the Seattle
metro area.
KSEA...Clear skies. Surface northerly winds of 6 to 8 knots this
morning will rise to northerly 8 to 12 knots this afternoon.
Gusts to 16 kts possible.
&&
.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.
Additional pushes likely occur for the Straight of Juan de Fuca
Monday through Wednesday, with potential for gales.
Coastal seas will remain well under 10 feet through the weekend
before building to around 10 feet by late Tuesday. Higher swells
to around 13 ft possible Wednesday.
&&
.FIRE WEATHER...
A dry and warm trend over the next few days with elevated fire
weather concerns through Tuesday. An upper level ridge over the area
this weekend with low level flow turning offshore Saturday night.
Daytime temps will warm into the 80s Saturday and 80s to 90s Sunday
and Monday. Relative humidity values will lower in the drier
locations, like Southwest Interior, 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.
&&
.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