694
FXUS66 KSEW 041651
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
951 AM PDT Wed Jun 4 2025

.SYNOPSIS...Strong high pressure remains positioned offshore for
the next several days. Expect mostly dry and mild conditions
during this time, but a pair of weak disturbances will bring
slightly cooler temperatures and increased cloud cover Wednesday
and Friday. A more significant warm up arrives late this weekend
as the upper ridge moves over the Pacific Northwest.

&&

.SHORT TERM /TODAY THROUGH THURSDAY NIGHT/...No significant
changes made to the forecast this morning. The previous discussion
can be found below along with updates to the aviation and marine
sections:

High pressure remains solidly in place offshore over the eastern
Pacific this morning. A weak disturbance embedded in the flow will
enhance the onshore flow today and bring more widespread clouds
that persist into the day, as well as cooler temperatures some 5
degrees or so cooler than we saw yesterday afternoon across the
Puget Sound region. With some weak lift ahead of this impulse,
can`t rule out a little bit of drizzle in the cloud layer,
especially along the coast this morning. Low-level onshore flow
will ease Thursday for decreasing clouds as the ridge begins to
build closer to the local area. This will bring temperatures well
into the 60s along the coast and into the upper 70s for the
warmest portions of the interior.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...Another disturbance will
flatten out the ridge on Friday, providing for another deeper
onshore push and a brief pause to the warmer temperatures.
However, ensemble guidance continues to remain in strong
agreement that the upper high pressure will begin to amplify
over the late this week through the weekend.

Temperatures will more significantly Sunday, with weak low-
level flow and the strong ridge overhead bringing temperatures
well into the 80s for much of the interior. This will bring
Moderate (Orange) HeatRisk across most of the interior. Some
areas south of Puget Sound and into the Cascade foothills have a
better than 60% chance of reaching into the lower 90s.
Confidence decreases into the first half of next week, but it`s
likely that Monday will be similarly warm (especially for areas
east of Puget Sound). However, ensemble guidance begins to
depict larger ranges of potential values as there is some
uncertainty with respect to the ridge flattening out.
Regardless, it`ll at least be one or two very warm days across
the region and it`s worth noting that area water temperatures
will remain cold.

&&

.AVIATION...Widespread marine stratus remains overhead much of
western Washington this morning. Cigs are largely MVFR, with
southerly to variable surface winds. Given the light gradients,
expect a later break up time of the consolidated stratus. Things
will start to break up around 20Z, but full breakout is not
expected. Things will improve to VFR thereafter, but OVC to BKN
layers of 040-050 remain likely. Another round of stratus possible
tomorrow morning, but likely not as widespread as this morning.

KSEA...MVFR cigs and light southerly flow this morning to around 5
kt. The marine stratus will remain overhead through much of the day
today, with more noticeable break up expected around 20Z. Full
clearing is not expected, and there will still be a BKN to OVC layer
040 and higher for the late afternoon and evening period. Another
round of stratus is likely tomorrow morning, reflected by a lower
BKN layer around 11Z.

21

&&

.MARINE...Surface high pressure will continue to remain offshore
throughout much of this week. Weak systems passing along the
periphery of the high will lead to varying degrees of onshore flow.

Diurnally driven westerlies will likely reach small craft advisory
strength at times in the central and east Strait of Juan de Fuca
most afternoons and evenings during the second half of the week.
27/21

&&


.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...None.
&&

$$