740
FXUS66 KSEW 112227
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
327 PM PDT Fri Jul 11 2025

.SYNOPSIS...Upper ridging over the area today into the weekend
will keep conditions warm and dry across western Washington
through Sunday. A brief reprieve in temperatures is possible on
Monday as a system slides southward along British Columbia and
skirts the area. Another warm up is expected Tuesday and Wednesday,
with highs potentially reaching the 90s for some lowland
locations.

&&

.SHORT TERM /TONIGHT THROUGH MONDAY/...Upper level ridging will
build over the area today and continue to influence the region
into the weekend, promoting warm and dry conditions across western
Washington. Satellite imagery still shows some stratus along the
coast this afternoon with clear skies across the interior. High
temperatures this afternoon will climb into the mid 70s to mid
80s across the interior, but remain cooler along the coast, topping
out in the 60s to low 70s.

Flow will become more zonal on Saturday across the area as the
ridge flattens somewhat, but expect conditions to remain similar
to today. Onshore flow will continue through the weekend for
additional rounds of morning stratus along the coast, Southwest
Interior, and along the Strait of Juan de Fuca. Conditions will
remain warm and dry, with afternoon high temperatures expected to
be in the upper 70s to mid 80s across the interior on Saturday,
and in the upper 60s along the coast. Highs look to climb a few
degrees on Sunday as ridging starts to amplify offshore, with
temperatures looking to top out in the low to upper 80s across the
interior and in the 70s along the coast. Overnight lows both days
will generally be in the 50s for most spots, but may not dip down
past the low 60s for the urban corridors east of the Sound (generally
from Tacoma to Everett). Areas of Moderate HeatRisk are likely
across the central and south Sound on Saturday, however by Sunday,
expect more widespread Moderate HeatRisk to be present across the
majority of the interior lowlands.

Guidance remains in decent agreement with a positively tilted
trough sliding down across British Columbia on Monday and skirting
western Washington. While this trough will not bring much in the
way of any precipitation to the area, it will act to bring some
additional cloud cover and a brief reprieve in temperatures. High
temperatures will fall a few degrees from Sunday`s highs and will
mainly top out in the upper 70s to mid 80s across the area.

.LONG TERM /TUESDAY THROUGH FRIDAY/...Ensembles continue to show
ridging amplifying over the region again by Tuesday and Wednesday,
with a thermal trough at the surface building northward along the
coast. This will promote another warm up across western Washington.
Uncertainty exists in just how warm temperatures will get across
the region- and especially in how warm the overnight temperatures
will remain. Afternoon highs look to climb a few degrees each day.
Temperatures look to peak on Wednesday, with much of lowlands
across the central and south Sound looking to climb into the upper
80s to low 90s. Overnight temperatures will remain warm, mainly
in the upper 50s to low 60s for much of the area, and will provide
little relief to the heat during the day. This will bring widespread
Moderate HeatRisk to western Washington.

Ensembles remain in disagreement regarding the break down of the
ridge over the area late in the week, though generally indicate an
overall cooling trend starting Thursday. At this time, high
temperatures look top out in the upper 70s to mid 80s on Thursday
with further cooling expected on Friday- with afternoon highs
topping out in the mid to upper 70s.

&&

.AVIATION...Northwest flow aloft with upper-ridging overhead. At the
surface, large-scale subsidence is well reflected as skies are
clear. VFR expected today but - stratus along the immediate
coastline will march inland tonight as low-level onshore flow
strengthens. MVFR/IFR to localized LIFR stratus (and patchy fog) is
in the offing into Saturday morning. Status will arrive over coastal
terminals around 00-02z Saturday and interior terminals around 12-
14z. Skies will trend clear late Saturday morning with VFR returning
by the afternoon. Mainly NW winds 5-10 kt (lighter overnight) but a
push through the Strait of Juan de Fuca this evening will bring
gusts upwards to 25 kt for KCLM.


KSEA...VFR continuing into the evening. Skies will be clear tonight,
but the NBM has a 40-50% chance MVFR stratus making it back into
Puget Sound by Friday morning around 12z. Confidence has lead the
potential to be included in the latest TAF with stratus lifting by
16-17z. Northwest winds at 5-10 kt.

McMillian

&&

.MARINE...High pressure offshore is leading to increased low-level
onshore flow. A SCA is posted for the central/eastern Strait of Juan
de Fuca along with Admiralty Inlet through early Saturday morning.
Gusts could flirt near low-end gales. Expect diurnal pushes to
continue throughout into early next week. Over the coastal waters,
winds will pick up late this weekend into next week (exceeding 20 kt
in the outer coastal waters Sunday night). Seas will also increase
from 3-5 feet today to 5 to 7 feet this weekend, continuing up to 6
to 10 feet Sunday night into Monday.

McMillian

&&

.FIRE WEATHER...Clear skies and relatively light winds across
western Washington today should allow for minimum RH values this
evening to reach the 25 to 35% range over the mountains and across
the interior around and south of Puget Sound. More robust onshore
flow this weekend will help usher in more moist air with min RHs
back into the 30% to 40% range, despite high temperatures remaining
in the 80s. A trough looks to edge towards the region on Monday,
which will allow for a brief reprieve with slightly cooler
temperatures.

Uncertainty remains high on the exact evolution of the weather
pattern beginning Tuesday and through much of next week. However,
the general warming trend peaking next Tuesday and Wednesday remains
on track, with a thermal trough developing along the coast. Flow
looks to periodically turn offshore, particularly at night, but
winds remain northerly through the interior. Fire weather concerns
remain elevated beginning Tuesday as minimum RH values look to drop
into the 25% to 35% range across much of the Cascades and the
interior lowlands south of Seattle. While the trend has been moving
towards less-elevation conditions, we are certainly not out of the
woods yet for next week. The pattern will continue to be monitored.

62

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Dense Fog Advisory until 2 PM PDT this afternoon for Coastal
     Waters From Cape Flattery To James Island Out 10 Nm-Coastal
     Waters From James Island To Point Grenville Out 10 Nm-
     Coastal Waters From Point Grenville To Cape Shoalwater Out
     10 Nm-Grays Harbor Bar.

     Small Craft Advisory until 6 AM PDT Saturday for Central U.S.
     Waters Strait Of Juan De Fuca-East Entrance U.S. Waters
     Strait Of Juan De Fuca.

     Small Craft Advisory from 5 PM this afternoon to 5 AM PDT
     Saturday for Admiralty Inlet.

&&

$$