265
FXUS66 KSEW 121651
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
951 AM PDT Sat Jul 12 2025

.SYNOPSIS...Upper ridging over the area this weekend will keep
conditions warm and dry across western Washington. 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 through Thursday, with highs potentially
reaching the 90s for some lowland locations.

&&

.SHORT TERM /TODAY THROUGH MONDAY/...The forecast remains largely
on track with latest satellite imagery showing stratus already
scattering along the coast and across the interior this morning.
Temperatures this afternoon will climb into the mid 70s to mid 80s
across the interior lowlands and in the upper 60s to low 70s for
areas along the coast. The previous discussion follows below,
with updates made to the aviation, marine, and fire sections. 14

Broad high pressure over the West will keep western WA warm and
dry through the weekend and early next week, with Minor to
Moderate Heat Risk. Interior temperatures will be in the upper 70s
to mid 80s today, and 80s to lower 90s on Sunday. Lows will be in
the mid 50s to around 60. The coast will be cooler and in the 60s
with NW onshore winds. Weak upper level troughing over B.C. will
help knock temps down a few degrees on Monday. 33

.LONG TERM /TUESDAY THROUGH FRIDAY/...Strong high pressure is
anchored offshore next week, deflecting any precip to our north,
while maintaining a warm a dry air mass over the region.
Temperatures will peak on Wednesday and Thursday with daytime
highs in the 80s to lower 90s and lows in the 60s. Much on the
interior and Cascade valleys will be in a Moderate Heat Risk
category. Elevated fire weather conditions are also expected with
minimum humidity percentiles in the 20s and 30s. Troughing over
B.C. will push temps down a few degrees late in the week (but
still tracking warmer than normal). No precip in sight. 33

&&

.AVIATION...Northwesterly flow aloft as an upper level ridge
slides over western Washington. Some high level clouds will move
over the area this morning along with marine stratus slowly
spreading from the coastline. MVFR/IFR stratus not as widespread as
expected, but what`s present will clear out into the afternoon.
Light northerly winds increasing to 8 to 12 knots this afternoon.

KSEA...VFR conditions this morning as stratus struggled to fill into
over the terminal. VFR will persist today, with northerly winds 8 to
12 knots throughout the afternoon.

Mazurkiewicz/McMillian

&&

.MARINE...Surface high pressure continues offshore with low level
onshore flow through the area waters. The previous SCA has expired
for the central/eastern strait and Admiralty inlet. Diurnally driven
pushes will continue through the Strait into early next week.
Northerly winds will increase over the outer coastal waters Sunday
night with the potential to reach small craft advisory strength.

Combined seas 4 to 6 feet will gradually increase to around 6 to
8 feet late Sunday into Monday. Seas look to remain elevated for
the first half of next week.

Mazurkiewicz/McMillian

&&

.FIRE WEATHER...High pressure over the region will bring  warm and
dry conditions to the area this weekend. Modest onshore flow will
provide for excellent overnight recoveries for most of the lowlands.
However, Sunday afternoon will see RH values dip down into the 25-
35% range for areas in the interior. A weak trough likely slides
through the region on Monday, boosting cloud cover and humidities,
as well as bringing cooler temperatures into the region. Elevated
fire weather concerns return by the middle of next week, however,
with minimum RH values approaching critical thresholds. While flow
remains mostly northerly or light northerly, the combination of
daytime breezes overlaying the lowest RHs may elevate concerns
around Wednesday and Thursday for much of Western Washington.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...None.
&&

$$