High Surf Advisory 4, NWS Seattle, WA

Area Forecast Discussion
National Weather Service Seattle WA
300 PM PDT Tue Oct 15 2019

.SYNOPSIS...A frontal system will slowly pass through Western
Washington this evening and tonight. A series of systems will follow
and make their way through the region throughout the remainder of
the week, keeping the pattern wet and unsettled.

&&

.SHORT TERM /TODAY THROUGH THURSDAY/...Current radar shows the
precip associated with the front making progress into W WA faster
than models suggested with current obs showing rain not only along
the coast but also on Whidbey Island and in Bellingham. As
such...have upped late afternoon/evening PoPs accordingly. Careful
not to place all faith in the radar though...as some echoes showing
up over the eastern shores of the Sound do not seem to be producing
much of anything when measured against ground obs. Thus for the
Seattle metro area...looks like precip could hold off until right
around the time for the evening commute.

Aside from the earlier than expected start...models remain on track
and in sync for the remainder of the short term. A secondary...much
better organized front will then pass through the region Wednesday
afternoon and evening keeping precip in the forecast. This front
looks to have stronger winds associated with it bringing breezy to
locally windy conditions not only to the preferred north interior
but also to locations along the Sound. Model guidance remains
borderline with regards as to if winds in the north interior
/Western Whatcom, Western Skagit, the San Juans and Admiralty Inlet/
will reach advisory criteria...but the combination of this
potentially being the first event of the season with many trees
retaining their leaves thus leaving plenty for the wind to pull on
led thinking to err on the side of caution. Thus...will be issuing a
wind advisory for the aforementioned areas with the afternoon
forecast.

The hits just keep coming as yet another system will pass through
the region on Thursday, brining more rainfall and another shot of
breezy winds along portions of the Sound. Inherited forecast had
some mentions of thunder associated with this system as well as for
Wednesday as well. A look over stability parameters suggests
probabilities are on the slim side and as such have removed such
wording.

Temps for the short term hang pretty close to climatological normals
although will see temps fall about a degree each day as the sun goes
away for a while...with highs generally in the mid to upper 50s for
most lowland locations. The plus side of the cloud cover is that
overnight lows will remain pretty static and generally mild-ish with
most lowland locations staying in the mid to upper 40s.  SMR

.LONG TERM /FRIDAY THROUGH MONDAY/...While the broad upper
level trough over the western US will shift eastward to more favor
the center of the country the continued presence of an upper level
low over the gulf of Alaska will keep rain in the forecast at least
into Saturday. Models are starting to suggest a slight...very
slight...break in the action Saturday night and maybe into Sunday
morning...the GFS more so than the ECMWF. But both models show a
system moving in Sunday morning bringing...you guessed it...more
rain. As such...this break really does not warrant any advertising
/or hope/ at this time. Monday will see yet another upper level
trough enter the area keeping area umbrella racks busy into the
start of next week.  SMR

&&

.AVIATION...Southwesterly flow aloft as a system approaches the
Pacific Northwest. High clouds over the area with mid level clouds
along the coast. VFR cigs through tonight for most of W WA with MVFR
expected along the coast. Rain will slide into the area this evening
with rain around through Wednesday. MVFR cigs by Wednesday morning
for portions of the interior. Winds generally 5 to 12 knots with
gusts up to 22 knots across portions of the northern interior.

KSEA... VFR cigs through tonight. Mid level clouds by this evening
with rain around later tonight into Wednesday. MVFR cigs possible by
later Wednesday morning. Winds generally southerly 5 to 12 knots. JD

&&

.MARINE...A strong front moving through the coastal waters this
afternoon will slide inland this evening through tonight. A gale
warning is in effect for the coastal waters. A gale warning has also
been issued for the eastern Strait and Northern Inland waters
Wednesday morning through the afternoon. SCA level winds elsewhere
through Wednesday. SCA for rough bar for Grays Harbor Bar with
combined seas 10+ feet. Additional weather systems will slide
through the waters this week with additional headlines needed. Seas
in the 15 to 25 feet range by early Thursday. JD

&&

.HYDROLOGY...A series of wet systems moving through the area
today into early next week will cause rivers to rise. As such, the
Skokomish will likely need to be monitored although given how early
in the hydro season it is...it may take some time for the river to
react. Otherwise...river flooding is unlikely over the next seven
days.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Wind Advisory from 8 AM to 5 PM PDT Wednesday for Admiralty
     Inlet Area-San Juan County-Western Skagit County-Western
     Whatcom County.

PZ...Gale Warning until 5 PM PDT Wednesday 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-
     Coastal Waters From Point Grenville To Cape Shoalwater 10
     To 60 Nm-Coastal Waters From Point Grenville To Cape
     Shoalwater Out 10 Nm.

     Small Craft Advisory for rough bar until 5 PM PDT Wednesday for
     Grays Harbor Bar.

     Small Craft Advisory until midnight PDT tonight for East
     Entrance U.S. Waters Strait Of Juan De Fuca-Northern Inland
     Waters Including The San Juan Islands.

     Gale Warning from midnight tonight to 5 PM PDT Wednesday for
     East Entrance U.S. Waters Strait Of Juan De Fuca-Northern
     Inland Waters Including The San Juan Islands.

     Small Craft Advisory until 9 PM PDT this evening for West
     Entrance U.S. Waters Strait Of Juan De Fuca.

     Small Craft Advisory from 7 AM to 5 PM PDT Wednesday for Central
     U.S. Waters Strait Of Juan De Fuca.

     Small Craft Advisory until 5 PM PDT Wednesday for Admiralty
     Inlet-Puget Sound and Hood Canal.

&&

www.weather.gov/seattle