847
FXUS66 KSEW 111036
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
336 AM PDT Thu Jul 11 2024

.SYNOPSIS...Flat upper level ridge over Western Washington into
the first part of next week. Upper level flow becoming
southwesterly Tuesday or Wednesday in response to an upper level
trough well offshore. Low level flow remaining onshore for the
next week.

&&

.SHORT TERM /TODAY THROUGH SATURDAY/...Satellite imagery shows
stratus along the coast extending eastward a little down the
Strait of Juan de Fuca. Clear skies over the remainder of the
area. Temperatures at 3am/10z were in the mid 50s to mid 60s.

Little change in the pattern for the next three days. Flat upper
level ridge over Western Washington with 500 mb heights in the mid
580 dms. Low level onshore flow of varying degrees through
Saturday. Stratus developing along the coast each evening/early
morning moving eastward in the early morning hours but at this
point it does not look like it will get east of the Puget Sound.
High temperatures in the mid 70s to mid 80s over the interior with
mid 60s to lower 70s for the coast. Lows with the onshore flow
will be cooler than the readings the last few days, in the 50s and
lower 60s.

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...Small change in the
pattern Tuesday or Wednesday with the upper level flow becoming
southwesterly in response to an upper level trough well offshore.
500 mb heights stay in the lower to mid 580 dms range. The
operational GFS has a trough moving inland Monday but this
solution is somewhat of an outlier looking at the ensembles. The
ECMWF does not indicate a trough Monday. Low level flow remaining
onshore through the period. Persistence a good forecast with some
stratus developing along the coast each evening creeping inland
overnight but for the most part staying west of the Puget Sound.
High temperatures remaining in the mid 70s to mid 80s over the
interior and mid 60s to lower 70s along the coast. Felton

&&

.AVIATION...WSW flow aloft through the TAF period. Largely VFR for
most terminals today but KHQM has a 40-50% chance of IFR to MVFR
cigs developing between 11-13z before clearing towards 19-21z if
manifests. Low-level onshore flow looks to prevail with an
additional round of marine stratus possible overnight and into
Thursday for coastal terminals and maybe a couple inland as well.
VFR mostly elsewhere.


KSEA...VFR throughout the TAF period. Surface winds varying between
NE and NW around 5 to 10 kt.

McMillian

&&

.MARINE...A stout surface high well offshore will remain in place
into next week with lower pressure inland. Currently, a gale warning
is in place for the central and eastern strait but will be allowed
to expire this morning. However, it`ll replaced by another round of
SCA entering this afternoon-evening into the overnight hours. SCA
are also in action for the coastal waters today, and may need to be
extended well into Friday for the outer zones due to northerly
winds. Persistent onshore flow will remain in place into the weekend
with diurnally driven westerly pushes through the strait, possibly
accompanied with additional headlines.

Seas increasing to 6 to 8 ft today and nearing 10 ft tonight into
Friday for the outer coastal waters. Seas should subside into the
weekend.

McMillian

&&

.CLIMATE...Seattle average temperature for the first 10 days of
July is 72.7 degrees. This is the 2nd warmest first 10 days of
July in 80 years of records at Seattle-Tacoma airport. The warmer
year was 2015 where the first five days of the month were in the
90s and the average temperature for the first 10 days of the month
was 73.6 degrees. July 2015 is the warmest July on record in
Seattle. Felton

&&


.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Gale Warning until 7 AM PDT this morning for Central U.S. Waters
     Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of
     Juan De Fuca.

     Small Craft Advisory from 2 PM this afternoon to 5 AM PDT Friday
     for Central U.S. Waters Strait Of Juan De Fuca-East
     Entrance U.S. Waters Strait Of Juan De Fuca.

     Small Craft Advisory from 2 PM this afternoon to 2 AM PDT Friday
     for Coastal Waters From Cape Flattery To James Island Out
     10 Nm-Coastal Waters From James Island To Point Grenville
     Out 10 Nm-Coastal Waters From Point Grenville To Cape
     Shoalwater Out 10 Nm.

     Small Craft Advisory until 5 AM PDT Friday 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.

&&

$$