956
FXUS66 KSEW 020311
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
811 PM PDT Tue Jul 1 2025

.SYNOPSIS...Southwest flow aloft will maintain warm and dry
conditions through Wednesday. A weak, dry trough will pass over
the region towards the end of the week, promoting onshore flow and
bringing in cooler temperatures through the holiday weekend. Zonal
flow will develop by the beginning of next week, maintaining mild
and dry conditions across western Washington.

&&

.SHORT TERM /TONIGHT THROUGH FRIDAY/...Another warm day in the
interior today with highs in the mid to upper 80s (mainly central
and south sound). We`ll see increasing clouds overnight with an
onshore push. 33

Previous discussion...The eroded morning stratus has given way to
clear skies across western Washington this afternoon. As high
pressure aloft slowly shifts eastward and onshore flow
strengthens, temperatures will follow a cooling trend. High
temperatures today will lower a few degrees from yesterday,
peaking in the low 80s across the interior and in the mid to upper
60s along the Pacific Coast.

The aforementioned upper level ridge will continue to shift
eastward into Wednesday with an approaching weak upper trough
offshore. Onshore flow will promote another round of widespread
marine stratus in the morning, burning off by the afternoon and
giving way once again to mostly sunny skies. Temperatures will
continue to moderate, with highs Wednesday reaching the mid to
upper 80s across the interior and the low to mid 60s along the
coast.

A weak trough will push inland on Thursday, bringing in stronger
onshore flow and cooler temperatures. Localized drizzle may
develop below the stratus layer early Thursday morning, with
potential for an isolated shower or two over the Cascades Thursday
afternoon. Otherwise, the region will see clearing skies into the
afternoon with highs limited to the low to mid 70s across the
interior and in the upper 50s to low 60s along the coast.
Independence Day is on track to bring more of the same, with near
normal temperatures paired with another round of morning clouds
and afternoon sunshine.

.LONG TERM /SATURDAY THROUGH TUESDAY/...Zonal flow aloft will
develop over the Pacific Northwest over the weekend and into early
next week as a cutoff low strengthens over northern California.
This will result in continued mild conditions and mostly clear
skies throughout the holiday weekend and beyond. With this
pattern, this opens the door to the chance of a few light showers
near the northern coast and the North Cascades over the weekend,
although the chance of any precipitation remains fairly low at
this point. Ensembles indicate some potential for high pressure
to rebound over the western US towards the middle of next week,
which could result in another warm-up across western Washington,
but the exact details remain uncertain at this time.

15

&&

.AVIATION...Upper level ridge to the east with weak trough
developing offshore giving southwesterly flow aloft over the area
through Wednesday. In the lower level, there is increasing onshore
flow this evening. It remains VFR across most of western WA this
evening (with the exception of the coast as low stratus has already
arrived into KHQM with BKN007 being reported as of 03Z). The low
stratus with tonight`s marine push will continue to advance
eastward. IFR/LIFR conditions are expected along the coast (but no
further than the Olympics), with a good chance that MVFR stratus
will reach Puget Sound terminals early tomorrow morning (12Z-15Z).
The stratus will clear out likely by 18-19Z due to southwest flow
making it down to the surface overnight, with most surface winds
switching from north to south overnight, and another push through
the Strait of JDF will turn the winds northwesterly through the
afternoon amd evening of 6 to 10 kt before becoming lighter and
southwesterly through the evening.

KSEA...VFR with mostly clear skies this evening (might be some
higher cirrus at times). Winds continue out of the north-northeast
at around 10 kt with a couple gusts possible through dusk. Currently
NBM gives a 30% chance of MVFR stratus reaching the terminal
Wednesday morning between 12-15Z, with anticipated ceiling heights
being from 1,500-2,000 ft. Given the switch of winds to the
southwest (as flow aloft reaches the surface), skies will likely
clear after 17-18Z. Diffluence from a marine push to the north will
likely turn winds north after 00Z Thursday for a few hours through
the evening, becoming light and back to southwest by dusk.

Kristell/HPR

&&

.MARINE...High pressure will remain in place across the coastal and
offshore waters this week with thermally induced low pressure east
of the Cascades. A weak front will dissipate over the offshore
waters Wednesday.

Diurnal westerly pushes through the Strait of Juan de Fuca each
evening. The gale warning tonight for the Central and Eastern Strait
with small craft advisory northwesterlies in Admiralty Inlet have
been left in place. Late day small craft advisory westerlies
possible in the Strait each evening into the weekend.

21

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Gale Warning until 3 AM PDT Wednesday for Central U.S. Waters
     Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of
     Juan De Fuca.

     Small Craft Advisory until 5 AM PDT Wednesday for Admiralty
     Inlet.

&&

$$