746
FXUS66 KSEW 260258
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
758 PM PDT Wed Jun 25 2025

.SYNOPSIS...Low clouds and occasional light showers will
continue to spread across western Washington through Friday.
Shower chances will peak Thursday into Thursday night. Warming
and dry conditions are expected this weekend through Monday.
Temperatures will reach the upper 70s and 80s by Monday.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY/...No major changes to the
current forecast tonight. 33

Previous discussion...Weak waves embedded in shallow troughing
will move across the region through Friday. This will keep western
Washington largely cool and cloudy with occasional rain chances
(peaking Thursday/Thursday evening). Temperatures will top out in
the 60s to around 70 degrees each day. Rainfall totals will likely
be highly variable due to the showery nature but anywhere from a
trace to 0.20" is possible in most areas. Precipitation chances
will wind down across the region by Friday night.

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...The pattern shifts to
an amplifying ridge this weekend allowing for temperatures to
warm and dry conditions to prevail. Currently the warmest day of
the period will likely be Monday when temperatures reach back
into the upper 70s and 80s across the region. HeatRisk values
will generally be in the Minor (yellow) category over the
weekend with a few favored areas (Seattle, south sound, and
Cascade valleys) reaching the Moderate (orange) category Monday.

Forecast confidence falls off rapidly after Monday next week.
There are two primary drivers of the uncertainty - the evolution
of a weak upper level low located somewhere near California and
the breakdown of the ridge over the western US. The evolution of
these features next week is all over the map in the ensemble
guidance. The result in a 10th-90th percentile spread of 15-20+
degrees by late next week. The general consensus is that Monday
and Tuesday will be warm days, but how much cooling takes place
by mid to late week is highly uncertain. Similarly, while there
is good agreement that the week will start off dry, confidence
is low in if and when precipitation will return mid to late next
week.
-Wolcott-

&&

.AVIATION...Westerly to southwesterly flow aloft over W WA this
evening and continuing into Thursday. Surface winds at most
terminals generally south to southwesterly, although exceptions
include PAE at more north to northwesterly, and HQM and CLM more
westerly. Most terminals should align in direction by mid Thursday
morning to southwesterly. Speeds generally 7-12 kts this evening,
easing slightly to 5-10 kts overnight and for the remainder of the
TAF period.

VFR conditions over most terminals this evening although portions of
the northern Olympic Peninsula have seen cigs erode down into MVFR.
Incoming weather system will drag cigs down overnight with
widespread MVFR expected over W WA by early Thursday morning. Late
morning/early afternoon mixing may allow for some slight improvement
to cigs, with some spots possibly seeing a return to low-end VFR
conditions, however incoming rain Thursday afternoon may limit or
offset any such improvements.

KSEA...VFR conditions are expected to prevail into tonight. Cigs
will lower early Thursday morning between 8z-10z into MVFR. At this
time guidance is suggesting that ceilings will not lower into IFR,
as probabilities are 5% or less. Rain is expected to reach the
terminal around 19z-21z Thursday. Guidance hints at potentially
seeing some improvement into low-end VFR beginning between 21Z-00Z.
Not sure how significant this improvement will be, as some guidance
hints at ceilings returning to MVFR after 03Z. Southwesterly flow
will become more southerly overnight and remain that way through the
TAF period.

18/29

&&

.MARINE...A weak front will cross the waters tonight into Thursday.
Westerly pushes through the Strait of Juan de Fuca are favored each
evening. The push tonight is expected to remain below SCA criteria,
although wind gusts may approach or exceed 21 kt at times. Latest
guidance also keeps winds below SCA criteria for these daily pushes
down the Strait for the remainder of this week and into the start of
next. High pressure will rebuild over the waters Friday and persist
into the weekend, establishing northwest flow over the coastal
waters. This high will begin to weaken early next week.

Seas will generally be around 3-4 ft throughout the week, increasing
slightly during the weekend to 4-6 ft and persisting into early next
week.

29/18

&&

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

$$