096
FXUS66 KSEW 261048
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
345 AM PDT Thu Sep 26 2024

.SYNOPSIS...A brief lull in activity before another system moves
into the region this evening into Friday. This will bring another
round of rain and gusty winds. Conditions then expected to dry out
over the weekend. A series of weaker systems may move into the area
early next week.

&&

.SHORT TERM /TODAY THROUGH SUNDAY/...Western Washington is very
visibly between two systems as the rainmaker from yesterday has
moved into ID and western MT while incoming system still out over
the Pacific waters via current satellite imagery. Latest radar shows
echoes that would be consistent with a weak convergence zone over
northwestern Snohomish county...however a hole in the obs over that
location is making it difficult to verify that is actually precip or
isolated fog due to plenty of low level moisture from earlier rains
there.

Extremely weak ridging currently in place over W WA may allow for
some portions of the area to see partly to mostly sunny skies today
in advance of the next incoming front...although timing works out
that the coast will likely start to see clouds from this system
start to move in right at or just a little after sunrise. From this
point, clouds increase steadily throughout the day before main
precip expected to start up by early afternoon for the coast, early
evening for points east of the Olympics. Winds will be of concern
for some locations as the front passes through, as portions of
western Whatcom and Skagit counties as well as the San Juans may see
gusts late this evening and throughout the overnight hours. Speeds
are not expected to enter into headline criteria for the most part,
even though isolated gusts right up to the low end of Wind Advisory
criteria may occur. In such a borderline instance, while no
headlines will go out with morning forecast, it is important to note
that this appears to be the first wind event for W WA this autumn
season. As such, isolated downed tree branches or power outages may
be possible. The remainder of the CWA may also see occasional
breeziness, but nothing impactful is expected.

Lingering showers possible Friday morning...but conditions will dry
throughout the day as the area falls under the influence of the
backside of a building broad ridge largely centered over the
Rockies. This feature along with a lack of any real organized
pattern over the Pacific should keep the area dry for the remainder
of the near term.

Temperatures will remain mild with daytime highs generally in the
lower to mid 60s throughout the period.

18

.LONG TERM /MONDAY THROUGH THURSDAY/...A more convincing upper level
ridge shifting eastward through the area will allow dry conditions
to at least extend into Monday. Deterministic models having some
difficulty agreeing on system for Tuesday when it comes to timing
and southern extent. Ensembles are not having the best time with it
either although amongst the varying solutions at least a pattern
emerges where any precip will have a better likelihood of staying
north of Seattle. Both deterministic and ensemble solutions favor an
upper level ridge returning at some point during Wednesday bringing
a return to dry conditions into Thursday. NBM in forecast for both
Tuesday and Wednesday displays the varying solutions with chance
PoPs, reflecting more the uncertainty than the actual expected
chance of rain from the weather feature itself.

18

&&

.AVIATION...A break in the weather for most of the area in between
frontal systems, but a lingering convergence zone remains draped
across Snohomish County early this morning. This has resulted in
widely variable conditions with VFR holding in some spots under
mostly clear skies, low MVFR conditions under the CZ, and local IFR
conditions where fog and low stratus has taken hold. Expect this to
improve through the morning with lifting ceilings, but increasing
clouds ahead of the next front will spread eastward through the day.
Southerly winds increase into the afternoon and evening with gusts
into the 20 kt range for many (local gusts to 35 kt coastal and
northern interior terminals). Expect another round of lowering
ceilings to MVFR category along with return of rain late Thursday
into early Friday.

KSEA...MVFR ceilings continue at the terminal this morning with
potential (around 20%) for lowering into IFR for a few hours around
12-16z with residual moisture in place. Some improvement follows
through early afternoon, but gusty south winds return this evening
along with gradually lowering ceilings ahead of the next frontal
system. Gusty winds continue overnight along with return of rain,
before easing early Friday morning.    Cullen

&&

.MARINE...Winds have temporarily eased in between frontal systems,
but we`ll again see an increase in southerly winds over the waters
this morning as a low intensifies as it moves toward Haida Gwaii
through the day today. This will bring gales across portions of the
coastal waters - especially across the northern and outer zones - as
well as the eastern Strait of Juan de Fuca, northern inland waters,
and Admiralty Inlet as it approaches. Elsewhere, expect to see winds
solidly into the small craft range today and tonight with the
potential for some isolated stronger gusts immediately ahead of the
front. Meanwhile, seas will remain around 10 ft over the coastal
waters and build again with the next front passing. This will brings
seas into the 13 to 16 ft range over the coastal waters. Behind the
front, expect to see westerly winds through the Strait of Juan de
Fuca with lingering SCA conditions expected into Friday. Northerly
winds also redevelop over the coastal waters into the weekend, with
the potential to again reach advisory strength. Seas will also
remain above 10 ft into early Saturday morning.  Expect another
break in the active weather early next week, but another system may
bring building seas again by midweek.                       Cullen

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 5 AM PDT Friday for Grays Harbor Bar.

     Small Craft Advisory until 5 AM PDT Friday for West Entrance
     U.S. Waters Strait Of Juan De Fuca.

     Small Craft Advisory from 1 PM this afternoon to 5 AM PDT Friday
     for Central U.S. Waters Strait Of Juan De Fuca.

     Gale Warning from 3 PM this afternoon to 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 from 3 PM this afternoon to 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 Friday
     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 until 2 AM PDT Friday for Coastal Waters
     From Point Grenville To Cape Shoalwater 10 To 60 Nm-Coastal
     Waters From Point Grenville To Cape Shoalwater Out 10 Nm.


&&

$$