767
FXUS66 KSEW 160315
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
815 PM PDT Wed Oct 15 2025

.UPDATE...Mostly clear skies remain in place of western Washington
this evening with lowland temperatures already in the 40s to lower
50s. Inherited forecast remains on track for quiet conditions to
persist into Thursday. The Aviation section below has been updated.

&&

.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...Weak flow aloft as a transient ridge moves
southward tonight into Thursday. Terminals are VFR this evening with
winds decreasing (becoming calm or variable 2-4 kt as winds will
turn more southerly in most areas around midnight local time). Flow
will turn more onshore tonight into tomorrow. However given the weak
gradient tonight (combined with the dry weather past few days), the
push of stratus/fog will likely be limited from the coast to as far
inland as the south interior/Kitsap areas (12-15Z start to as late
as 18Z). Most terminals outside of this area tonight will remain VFR
with mid level clouds filling in with light scattered rain showers
likely Thursday evening. Ceilings will gradually lower with these
showers from VFR down to MVFR going into Friday morning. Winds will
remain out of the south 4-8 kt going through Thursday.

KSEA...VFR likely remaining through the TAF period. While chance of
IFR/LIFR are low, there still remains a medium chance of MVFR cigs
in the morning briefly from roughly 14Z through 17Z in the morning.
The dry conditions and weak onshore gradients tonight will most
likely keep lower CIGs/VIS to the west of the terminal (with only 2
out of 11 HREF members mentioning anything low near the terminal).
VFR mid level clouds are favored for the rest of the day with the
front passing, with low confidence in showers passing through the
terminal later (but high enough probability to put a PROB30 group
with the 06Z TAFs). Winds have calmed this evening - will turn south
by midnight and pick up 4-8 kt during the day Thursday.

HPR

&&

.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.
&&

$$