144
FXUS66 KSEW 040348
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
848 PM PDT Sat Oct 3 2026

.UPDATE...
Satellite imagery shows stratus has been pushed slightly off the
coast with the weak low level offshore flow. Stratus making it
back to the coastline early Sunday morning. For the interior
the stratus will form in place after 12z with the offshore flow
not strong enough to dry out the lower levels of the air mass.
Stratus dissipating by afternoon with highs a few degrees warmer
than Saturday for the interior. Thermally induced surface
trough shifting inland Sunday turning the low level flow onshore
along the coast. This will drop high temperatures around 5
degrees versus Saturday. Current forecast has the trends
covered. No update this evening. Felton

&&

.SYNOPSIS...
High pressure building overhead and weak offshore flow will maintain
mild and dry conditions this weekend. A system to the north will
flatten the ridge by the beginning of next week, with near-zonal
flow aloft and onshore flow at the surface maintaining seasonable
conditions with morning clouds and afternoon sun breaks.

&&

.SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/...

The current upper level ridge will see its axis shift eastward
over E WA Sunday. At the surface thermally induced surface
trough along the coast tonight will shift inland Sunday. Sunday
the warmest day for the interior with highs in the mid 60s to
mid 70s. Ridging overhead will flatten out into zonal flow
Sunday night. This change will help to facilitate a return to
onshore flow later Sunday and as such bringing daytime highs
more in line with seasonal normals Monday...generally in the 60s
for most lowland locations. Overnight lows remain generally
static, ranging from the upper 40s to lower 50s.

No precip expected in the short term.

18/Felton

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
Ridging builds over the eastern Pacific slowly Tuesday and into the
midweek period, which may allow for daytime highs to rebound a
handful of degrees back into the upper 60s to lower 70s by Thursday
and overnight lows remaining consistent with what is expected in the
short term. The ridge is then forced to retrograde as an upper level
low from BC drags a frontal system over the CWA Friday and into
Saturday. As this falls into day 6 and 7 territory, no surprise that
ensemble members have a wide array of opinions of how well this
front holds together and how much potential precip it will bring.
Ensemble mean generally leaning toward light precip with PoPs for
this time frame generally ranging 20-50 pct. This seems like a
reasonable solution for now. The main impact from this system will
be to drag temps solidly back into Climo...if not slightly
below...as daytime highs will range in the upper 50s to lower 60s by
Saturday.

18

&&

.AVIATION...
High pressure and offshore flow across western WA for dry and stable
conditions. The flow aloft is west to southwest. Low clouds and fog
likely developing across most lowland areas late tonight for
IFR to LIFR conditions. Skies clearing 18-21z Sunday with VFR
conditions expected in the afternoon and evening. 33

KSEA...VFR tonight. N/NE wind 10 kt easing to 5 kt or less
after 06z. IFR to LIFR cigs developing after 12z Sunday
morning. VFR expected by 21z Sun. 33

&&

.MARINE...
Offshore flow through Sunday with a thermal trough
along the coast. Low pressure will shift inland Sunday night with a
westerly push down the Strait of Juan de Fuca. Another push is
forecast Monday night. The flow remains onshore through the end of
the week. 33

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory from 5 PM Sunday to 5 AM PDT Monday for
     Central U.S. Waters Strait Of Juan De Fuca-East Entrance
     U.S. Waters Strait Of Juan De Fuca.

&&

$$