Ruston, Washington Weather Forecast Discussion

489
FXUS66 KSEW 252127
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
227 PM PDT Thu Sep 25 2025
.SYNOPSIS...Zonal flow continues through Friday as frontal systems
approach western Washington. Very light shower activity is
possible over the northwest coast on Friday evening into Saturday,
with more widespread rain moving in on Sunday. Unsettled weather
conditions are expected to linger through much of next week with
additional chances for rain.
&&
.SHORT TERM /TONIGHT THROUGH SUNDAY/...Mid and high level clouds
are streaming overhead this afternoon as zonal flow opens the
region to frontal systems into the weekend. Initially, light
showers will be prevalent along the far northwestern coast and in
through the San Juan Islands tomorrow and into Saturday.
Accumulations will be light and generally less than a tenth of an
inch. Southwesterly flow aloft will pick up on Saturday and
temperatures will climb slightly into the 70s before cooling off
again on Sunday. More widespread rain is expected to arrive Sunday
morning and persist into the start of next week. From early Sunday
morning through late Monday night, upwards of a half to three
quarters of an inch of rain is possible throughout the lowlands
with one to two inches in the Olympics and North Cascades. This
amount of rainfall will be extremely beneficial on drought starved
foliage throughout the region.
.LONG TERM /MONDAY THROUGH THURSDAY/...Active weather conditions
are likely to persist through much of the week with additional
rounds of rainfall through Thursday. One forecast element that
will take the next few days for more detail to emerge on is the
possibility for thunderstorms on Monday. It is not in the forecast
presently, but if the low off the coast is to position itself
favorably for moist southerly flow and ample dynamics to reach
western Washington, thunderstorms cannot fully be ruled out. There
are still a lot of forecast details like the position of the low
pressure system to be ironed out, but wanted to mention the
possibility not fully being eliminated. Temperatures will be in
the 60s, with 40s and 50s in the mountains and along the coast.
21
&&
.AVIATION...A weak frontal boundary sits east of the Cascades this
afternoon (with another frontal system to the west that will swing
by to the north this evening). Flow aloft is southwesterly, and will
eventually mix down to the surface later this evening (variable 5-10
kt north winds at the surface with gusts in the Strait of Juan de
Fuca up to 20-25 kt will become southerly tonight around 4 to 8 kt).
VFR conditions across all sites this afternoon with solid mid and
high level cloud decks (few sites still observing SCT030-035 this
afternoon). The high clouds will clear post-front late tonight with
marine air expected to bring widespread MVFR cigs (onsetting from 10-
15Z filling towards the interior terminals, and scattering/clearing
18-21Z from the interior to the coast). A few gusts in the north
interior may approach 20 kt Friday morning out of the south.
KSEA...VFR currently this afternoon with a few SCT035 clouds
remaining around the terminal (higher clouds overhead). Winds remain
out of the northwest 5-10 kt (and may wobble between the north and
west through around 03-05Z before turning southeastward around 5
kt). Stratus is likely Friday morning (with a 40-60% chance it is
down to MVFR at or above 2,000 ft). Arrival of the lower cigs is
expected 13-15Z with scattering/clearing from 18-21Z. Winds will
pick up out of the south mid to late morning 5-10 kt.
HPR
&&
.MARINE...A front sits east of the Cascades, with another frontal
system clipping the northern waters later today. High pressure will
weaken over the coastal waters today as a result. A strong push of
westerlies is expected this afternoon and evening for the
central/east Strait of Juan de Fuca (a small craft advisory was
issued through 11 PM PDT for winds of 15-25 kt). Seas and winds
continue to decrease in the coastal waters with light west winds and
seas at 6-8 ft.
A stronger frontal system will approach the region Friday into the
weekend. Seas will build up to 9-10 ft Saturday (at this time winds
are expected to remain below 20 kt with this frontal system, but
stay tuned to future forecasts as future forecasts will likely
result in increased winds given the expected fall-like nature of
this front). Behind this system, seas will decrease to 6-8 ft next
week, with another system Tuesday into Wednesday potentially
bringing in gusty south winds.
HPR
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 11 PM PDT this evening for Central
     U.S. Waters Strait Of Juan De Fuca-East Entrance U.S.
     Waters Strait Of Juan De Fuca.
&&
$$

NWS sew Office Area Forecast Discussion