483
FXUS66 KSEW 262155
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
255 PM PDT Thu Sep 26 2024

.SYNOPSIS...The next frontal system moves in tonight. This will
bring another round of rain and gusty winds, mainly north part.
Conditions then expected to dry out over the weekend. A series of
weaker systems may move into the area Tuesday and Wednesday.

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY/...Another round of wind and
rain is on its way as the next Pacific frontal system clips the
region. Most of the impacts will be over the northern Olympic
Peninsula and North Interior with gusty south winds to 30-40 MPH
(winds peaking overnight). Total rainfall will be less compared to
yesterday`s system with around 0.25-0.50" along the coast and in
the mountains and generally 0.10" or less in the interior. Light
rainfall will linger into early Friday then drier weather expected
toward the afternoon as this system lifts north into B.C. This
system will also generate high seas as mentioned below in the
marine section.

Cool, but mainly dry, weather prevails over the weekend with weak
upper level troughing over the Pac NW. Temperatures will be in the
low to mid 60s with lows in the 40s and 50s. Sunday will be
sunnier as the trough exits east and weak high pressure moves in.
33

.LONG TERM /MONDAY THROUGH THURSDAY/...Broad high pressure lingers
over the West into early next week with a dry Monday over western
WA. Temperatures are still tracking cooler than average with highs
mainly in the low to mid 60s and lows in the 40s. Wetter weather
returns on Tuesday as the next system slides in. Ensemble members
favor cool and wet weather extending into Wednesday with a
possible break on Thursday as another ridge moves in. 33

&&

.AVIATION...This afternoon: All terminals have improved to VFR as
high clouds build in ahead of the next cold front (expected to
sweep through tonight). Bands of rain showers are moving inland,
beginning in the northern terminals this afternoon. They will
spread to the remainder of Puget Sound and the South Interior by
this evening. The rainfall rates are significantly lighter than
yesterday, but a couple of isolated showers may drop visibilities
temporarily down to 3 miles. The showers will wrap up early Friday
morning. Ceilings will congeal down to widespread MVFR CIGs, with
IFR/LIFR CIGs/VIS likely in the South Interior Friday morning.
Skies will clear out later in the afternoon.

Winds will be more of an issue with this cold front. Strong
southerly to southwesterly winds are expected this afternoon and
evening ahead of the front. The strongest winds will be terminals
near the waters (including the coastline and all inner waterways).
The strongest gusts may exceed 30 to 35 kt. Timing of the strongest
winds will be out ahead of the front this evening, tapering back to
under 5 to 10 kt sustained Friday morning. Behind the front, winds
will turn to the north at 4 to 8 kt (by early Friday afternoon).

KSEA...VFR CIGs this afternoon (mix of low cumulus and mid level
stratus). Rain showers will arrive after 00-02Z from the west. CIGs
will not drop to MVFR until after 11-13Z (but will scatter out after
20-21Z to VFR, completely clearing by Friday afternoon). There is a
20% chance CIGs may drop to IFR. Strongest winds are expected to
arrive this afternoon evening, with gusts potentially exceeding 25
kt out of the south. They will drop back to around 5 to 10 kt Friday
morning, and turn northerly early Friday afternoon post-front.
HPR

&&

.MARINE...A cold front remains on track to sweep through the region
rest of today into Friday morning. Rain showers will continue over
the coastal waters, and spread inland (low risk of thunder over the
coastal waters until early evening). Winds remain the primary impact
with this system. Winds have picked up over the coastal waters, with
winds gusting over 25 kt down by buoy 41. Higher winds up to gales
are expected in the northern 2 sections of the coastal waters,
central/east Strait of Juan de Fuca, Admiralty Inlet, and Northern
Inland Waters. The southern coastal water zones, western Strait of
Juan de Fuca and the Puget Sound waters will still see gusty winds
affecting small craft. Timing: the strong southerly winds continue
to pick up in the coastal waters this afternoon, and will arrive in
inland waters late afternoon and evening. Once the front passes,
winds will begin to taper back out of the southwest Friday, and
switch to the north behind the front.

Seas will be the next main concern post-front. Wave heights will
build up to 11 to 17 feet at 13 seconds Friday over the coastal
waters, and Strait of Juan de Fuca. The highest waves will be in the
outer coastal waterways. They are expected to remain elevated
through Saturday morning (additionally, the Grays Harbor bar will be
rough through Friday night).

Behind the front, waves will drop to 6 to 8 feet for the remainder
of the weekend. Breezy north winds up to 20 kt are possible in the
outer coastal waters Saturday afternoon. Otherwise winds will
decrease below 10 kt going into next week, with seas dropping to 3
to 5 feet until mid week next week, building back to over 10 feet
next Wednesday.

HPR

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 11 PM PDT Friday for Grays Harbor Bar.

     Small Craft Advisory until 5 AM PDT Saturday for Coastal Waters
     From Point Grenville To Cape Shoalwater 10 To 60 Nm-Coastal
     Waters From Point Grenville To Cape Shoalwater Out 10 Nm-
     West Entrance U.S. Waters Strait Of Juan De Fuca.

     Gale Warning until 5 AM PDT Friday for Central U.S. Waters
     Strait Of Juan De Fuca.

     Gale Warning until 5 AM PDT Friday for Admiralty Inlet-East
     Entrance U.S. Waters Strait Of Juan De Fuca-Northern Inland
     Waters Including The San Juan Islands.

     Small Craft Advisory until 5 AM PDT Friday for Puget Sound and
     Hood Canal.

     Gale Warning until 9 PM PDT this evening for Coastal Waters From
     Cape Flattery To James Island 10 To 60 Nm-Coastal Waters
     From Cape Flattery To James Island Out 10 Nm-Coastal Waters
     From James Island To Point Grenville 10 To 60 Nm-Coastal
     Waters From James Island To Point Grenville Out 10 Nm.

     Small Craft Advisory from 9 PM this evening to 5 AM PDT Saturday
     for Coastal Waters From Cape Flattery To James Island 10 To
     60 Nm-Coastal Waters From Cape Flattery To James Island Out
     10 Nm-Coastal Waters From James Island To Point Grenville
     10 To 60 Nm-Coastal Waters From James Island To Point
     Grenville Out 10 Nm.

&&

$$