899
FXUS66 KSEW 131658
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
958 AM PDT Sat Jul 13 2024

.SYNOPSIS...An upper level ridge remains over Western Washington
through the weekend into next week with continued low level
onshore flow. This will maintain above normal temperatures, but
still notably cooler than the start of this week. No rain expected
with only subtle variations in the strength of the marine pushes
each night.

&&

.SHORT TERM /TODAY THROUGH MONDAY/...No significant changes made
to the forecast this morning. The previous discussion can be found
below:

Mostly clear skies in place over much of W WA this morning with
the exception of along the coast, where marine stratus pushed
inland to varying degrees. Should see those numbers fall a little
bit more early this morning until the daytime heating kicks in
after sunrise.

Will see zonal flow remain in place today and into Sunday with
ridging building over BC and an upper level low developing over
the Pacific waters off CA. The ridging to the north will gradually
start to win out as a weak ridge does begin to build over W WA
throughout the day Monday.

High temps today will depend greatly on location, as the coast and
water adjacent locations will see highs ranging from the mid 60s to
lower 70s and look to stay that way for the entirety of the short
term. The interior will once again heat up with most locations
getting into the mid to upper 80s today, although locations north of
Everett may be slightly cooler...in the lower to mid 80s. Some
cooling expected for Sunday and Monday with interior temps generally
in the upper 70s to lower 80s.

18

.LONG TERM /TUESDAY THROUGH FRIDAY/...The ridge shifts eastward
throughout the day Tuesday and Wednesday, however the trough in
place over the Pacific does little to move inland, keeping W WA in
between systems and a generally dry southwesterly flow. That being
said, this flow may introduce a little bit of instability for
Wednesday and while deterministic models suggest hints of an
isolated shower or thunderstorm, a look at the ensembles shows that
only an extreme minority of solutions come to this same conclusion.
Thursday and Friday sees the ridge to the east intensify, but with
no further movement eastward, this ends up pushing the trough off
the Pacific back north into the BC coast.

High temps Tuesday and Wednesday warm up with the interior returning
to temps in the mid to upper 80s Tuesday and in the upper 80s to
lower 90s Wednesday. Much like Sunday and Monday in the short term
forecast, Thursday and Friday see some cooling, with highs Thursday
in the lower to mid 80s and Friday in the upper 70s to lower 80s.

18

&&

.AVIATION...West winds aloft with zonal flow over western
Washington. VFR conditions expected through the TAF period, with the
exception of HQM, where the marine stratus layer remains along the
coast this morning with LIFR ceilings. The stratus layer will
continue to slowly creep eastward throughout the morning,
approaching SHN and just west of OLM. Stratus will slowly evaporate
late this morning into early this afternoon with HQM returning to
VFR conditions briefly before the marine layer redevelops and
conditions return to IFR/LIFR along the coast. Winds are light and
variable this morning, with west to northwest (onshore) flow picking
back up to 5 to 10 kt this afternoon.

KSEA...Clear skies. Light north to northwest winds becoming 5 to 10
kt this afternoon.

LH

&&

.MARINE...Little change in the weather pattern with high pressure
situated offshore and a thermal trough over eastern Washington. A
Small Craft Advisory continues through today over the outermost
coastal waters as gusty northwesterly winds up to 25 kt continues,
with the highest speeds concentrated farther than 30-40 NM offshore.
Diurnally driven pushes of westerly winds down the Strait of Juan de
Fuca will occasionally be strong enough to warrant additional
headlines into next week, with the next strongest push expected to
be Sunday evening.

Seas 6 to 9 ft across the coastal waters will decrease Sunday night
into Monday to around 4 to 6 ft through the beginning of next week.

LH

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 11 PM PDT this evening for Coastal
     Waters From Cape Flattery To James Island 10 To 60 Nm-
     Coastal Waters From James Island To Point Grenville 10 To
     60 Nm-Coastal Waters From Point Grenville To Cape
     Shoalwater 10 To 60 Nm.

&&

$$