Mt. Baker

000
FXUS66 KSEW 301728
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
1028 AM PDT Fri Oct 30 2026

.SYNOPSIS...
Weakening upper level low off the north coast will elongate and
continue to weaken through Saturday. What is left of the low
will move inland Saturday night. Upper level ridge building over
the area Sunday. The ridge will move east Monday allowing a warm
front to nick the north coast. Another ridge will build Tuesday
into Wednesday. The ridge will move to the east Thursday with a
splitting front moving into Western Washington. 

&&

.SHORT TERM /TODAY THROUGH SUNDAY/...Upper level low drifting 
southwest today. Flow aloft over Western Washington already 
southerly this morning. As the low moves southwest difluent flow
aloft developing this afternoon. This combined with a little 
daytime heating to increase the instability over the area will 
produce more widespread shower activity this afternoon 
especially over the interior. Increasing shower activity in the 
afternoon will knock a couple of degrees off the high 
temperatures with lower 50s common across the area. The forecast
high of 51 degrees for Seattle would be the coldest day since 
another 51 degree day back on May 15th. 

Upper level low elongating and weakening tonight and Saturday
but will still be off the coast by late Saturday afternoon. Jet
stream moving inland over Northern California. Shower activity
drying up quickly this evening. Shower chances becoming 
confined to the coast after midnight and to the coastal waters 
Saturday morning. Varying amounts of middle and high level
clouds moving through the area. Lows in the 30s and lower 40s.
If there is enough clearing chance for lows in the upper 20s in
the Lower Chehalis Valley and Southwest Interior. A Freeze 
Watch for these areas has been upgraded to a Freeze Warning. 
Highs Saturday in the lower to mid 50s.

Upper level low weakening to an upper level trough and moving
inland Saturday night. Nothing left with this feature by this
point. Light surface gradients early Sunday morning with patchy 
fog developing in the fog prone locations like the Southwest 
Interior. Lows in the 30s and lower 40s. 

Light onshore gradients Sunday morning for areas of morning low
clouds and fog. Upper level ridge building into the area during
the day making for a sunny afternoon. Highs in the lower to mid
50s. Felton

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Extended models in pretty good agreement with the upper level
ridge over the area Sunday night moving east Monday. This will
allow a warm front to nick the north coast later Monday into 
Monday night. Another upper level ridge building Tuesday 
remaining over Western Washington Wednesday but the ridge axis 
will be east of the area. Splitting front reaching Western 
Washington Thursday for a chance of rain. Highs in the mid 50s 
with some upper 50s Wednesday. Lows in the 30s and lower 40s. 
Felton

&&

.AVIATION...
Another round of steadier rain is rotating through the region this 
morning, bringing fairly widespread rain which is lowering ceilings 
and restricting visibility. Expect widespread MVFR conditions 
through the afternoon as this move through, with local pockets of 
IFR under heavier showers. As the day progresses, a winds become 
predominantly east or southeasterly. Showers begin to decrease as 
the low continues to lose strength over the area. With light winds 
and some clearing overnight, expect to see fog and low stratus 
development from around the Seattle metro area southward through KOLM 
and KCLS. Moderate confidence for the development of IFR conditions 
11-17z in these areas, with improvement into the late morning 
Saturday as the air mass begins to dry out at the low levels.

KSEA...MVFR conditions are expected in steadier rain this afternoon. 
Northerly winds will become east/southeast through the day, with 
rain tapering late afternoon or evening. This should bring a gradual 
clearing trend, but this will result in IFR fog/low stratus Saturday 
morning at the terminal. 

&&

.MARINE...
Weak surface low pressure over the coastal waters will remain in 
place into Saturday before dissipating as high pressure builds 
across the interior of Western Washington early in the coming week. 
East or southeast winds across the coastal waters and near the west 
entrance to the strait will occasionally reach 15 to 20 knots over 
the next couple of days until the offshore low finally dissipates. 
Otherwise, winds into early next week look to remain rather light 
across area waters. 

Coastal seas generally 4 to 6 feet today and into the weekend. They 
are expected to build back to around 10 feet Monday as another 
larger swell train reaches the waters. 

27/18

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Freeze Warning from midnight tonight to 9 AM PDT Saturday for 
     Lowlands of Lewis and Southern Thurston Counties-Middle 
     Chehalis River Valley.

PZ...None.

&&

$$