702
FXUS66 KSEW 140239
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
739 PM PDT Sun Apr 13 2025

.SYNOPSIS...Conditions expected to remain dry into Friday. High
pressure over Western Washington will continue to bring warmer
temperatures through Monday. On Tuesday high pressure will weaken
as a weak disturbance moves across the region. Conditions will
warm up again on Thursday and Friday as high pressure rebuilds.
Precipitation chances return next weekend.

&&

.SHORT TERM /TODAY THROUGH WEDNESDAY/...No updates to the forecast
this evening. Cirrus clouds are beginning to stream in and will
continue to move through the area tonight and into tomorrow.
Upper level ridging over the area will bring warmer temperatures
on Monday, with daytime highs generally in the mid- to-upper 60s
(warmer temperatures in the 70s possible in the southern interior
valleys). In addition, Monday`s overnight temperatures will
rebound into the upper 30s to low 40s. On Tuesday, the ridge will
weaken and a shortwave trough will move over the region. Models
are in good agreement that the bulk of the precipitation will stay
in British Columbia. If any precipitation does make it into
Western Washington, it will be limited to the Northern Cascades.
Daytime temperatures will also cool slightly on Tuesday. High
temperatures on Tuesday will be in the upper 50s along the coast
and mid 60s in the lowlands. By Wednesday, high temperatures will
be in the upper 50s to low 60s. An upper level ridge will continue
to intensify offshore Tuesday and Wednesday.

Ensemble and deterministic models are in general agreement that a
low will drop down from Canada on Wednesday. Previously the GFS
had the low pressure center passing over Central Washington (a
much wetter solution for Western Washington). However, the latest
run has the low pressure center moving along Eastern
Washington/Idaho. This eastern trajectory is seen as well with
the European model and WPC cluster analysis. With models starting
to agree on a solution, Wednesday is looking to remain mostly dry
(some precipitation possible along the Cascades but PoPs are low
around 20-25%).

.LONG TERM /THURSDAY THROUGH SUNDAY/...A strong upper level ridge
will move into Canada on Thursday and slowly make its way towards
Western Washington. Ensemble guidance is in good agreement for a
strong ridge to move onshore on Friday. Daytime temperatures will
gradually warm up Thursday into Friday (may see some low 70s on
Friday in a few locations).

Solutions begin to differ on Saturday and Sunday. The European
model has the ridge axis further east along the Rockies on Friday
and rain chances arriving as early as Saturday. However, the GFS
model still has the ridge axis over Washington on Saturday and
rain chances returning on Sunday. At this time, the European model
is better aligned with ensemble guidance solutions, with a
majority of ensemble members having the ridge axis along the
Rockies by Saturday and a trough moving into Washington Saturday
and Sunday.

29

&&

.AVIATION...High pressure with dry and stable conditions across
western Washington. VFR conditions will prevail through the
period. 33

KSEA...Mostly clear skies, VFR conditions, with N winds 5-10 kt.
33

&&

.MARINE...A thermal trough will develop along the coast with light
offshore winds through Monday. A weakening cold front will cross
the coastal waters Monday night, with N/NW winds increasing over
the outer coastal waters. Seas building to 10-14 feet on Tuesday,
primarily for the outer coastal waters. High pressure off the
coast will maintain onshore flow moving toward midweek. 33

&&

.HYDROLOGY...No river flooding expected in the next 7 days.

&&

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

$$