Forecast Discussion
Forecast Discussion for SEW NWS Office
805
FXUS66 KSEW 152127
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
227 PM PDT Wed Oct 15 2025
.SYNOPSIS...Clouds will increase and a little rain will reach
Western Washington Thursday night into Friday as a weak frontal
system moves through the area. A stronger system will move into
the region over the weekend bringing gusty winds, lowland rain,
and mountain snow. Unsettled conditions will continue into early
next week.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY/...The upper level ridge
offshore will begin to flatten tonight and allow a weakening
frontal system to reach the area Thursday night into Friday. QPF
will be minimal with this one...a few hundredths interior lowlands
to a quarter to half inch coast and mountains. This will open the
door for a stronger system to arrive over the weekend.
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...A more vigorous front
arrives Saturday night into Sunday. Snow levels will bump up to
7500 to 9500 feet in the warm sector ahead of the cold front, but
this will be relatively brief with snow levels falling back to
4500 to 5000 feet behind it on Sunday morning. It will be a
noteworthy early season system with QPF totals ranging from
around three quarters of an inch in the Olympic rain shadow to 3
or 4 inches in the Olympics and North and Central Cascades.
Though this is a good primer for area rivers, the antecedent dry
conditions lend little concern for any flooding at this time.
Standard breezy to locally windy conditions will apply with the
system. The trailing upper trough will waste little time coming
onshore with weak upper ridging leading to some drying Sunday
night into Monday. Forecast confidence in the details falls off
Tuesday and beyond with clusters/ensembles showing quite a spread
in solutions. A couple of weaker systems may brush the area
Tuesday into Wednesday, but upper ridging centered to our south
may act to blunt their impacts. 27
&&
.AVIATION...VFR with passing high clouds this afternoon. A switch to
onshore flow tonight will allow marine stratus to fill in along the
coast and as far inland as the eastern Puget Sound terminals
Thursday morning, generating areas of MVFR to IFR in low clouds.
Areas of fog are also possible Thursday morning, but will be less
widespread. Conditions will improve towards the late morning and
into the afternoon Thursday as a weak front moves across western
Washington. This will bring lower ceilings, though terminals are
favored to stay VFR with little more than a few light showers
Thursday afternoon.
KSEA...VFR with passing high clouds this afternoon. Winds generally
out of the NW 10 kt or less, becoming southerly 4 to 8 kt overnight
through Thursday. Brief MVFR conditions in lower ceilings and patchy
fog are possible Thursday morning if the stratus makes it eastward
of the Puget Sound, generally between 13z and 17z, but confidence is
low.
&&
.MARINE...A weak front will arrive Thursday night into Friday
with a modest increase in coastal seas but no impacts are
expected. A stronger frontal system will reach the waters
Saturday night into Sunday with headlines expected for most of the
waters. Coastal seas will build into the double digits this
weekend and could exceed 15 feet by later Sunday and remain above
10 ft into early next week. McMillian/27
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...None.
&&
$$
NWS SEW Office Area Forecast Discussion