063
FXUS66 KSEW 091602
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
902 AM PDT Sun Jun 9 2024

.UPDATE...No changes have been made in this morning`s update. The
previous discussion remains below along with an updated
marine/aviation section.

&&


.SYNOPSIS...One more warm and dry day today with a few showers
over the Cascades as a weak upper-level trough passes through the
region. Temperatures returning to near-normal this week with
mostly zonal flow, except a chance of showers associated with a
passing shortwave on Tuesday. Below-normal temperatures and a
wetter pattern is expected to begin Friday through the weekend.

&&

.SHORT TERM /TODAY THROUGH TUESDAY/...Satellite imagery showing a
weak frontal system encroaching along the coast. Otherwise, mostly
high clouds across western Washington this morning with
temperatures in the ranging in the 50s to low 60s in some spots.
In the upper levels, water vapor imagery shows the incoming trough
axis offshore with a ridge departing to the east.

The trough and associated surface front will move through the
region today, but with very limited moisture, most of the area
should stay dry tomorrow. Cloud cover in the morning will give to
a mix of sun and clouds in the afternoon, allowing one more warm
day with highs in mid to upper 70s through the interior, and the
upper 60s to low 70s along the coast. Low temperatures will be the
upper 40s to low 50s. A few convective showers are possible over
the mountains, in particular over the North Cascades, with lapse
rates sufficient enough to allow for a few showers and perhaps a
lightning strike or two. Widespread shower activity is not
anticipated, with the majority occuring east of the Cascade crest.

The trough departs Sunday night, with zonal flow, becoming almost
weak ridging aloft, developing. This will allow temperatures to
cool to closer to normal on Monday, with highs in the upper 60s to
low 70s. The pattern of cloudy mornings breaking up to mostly
sunny in the afternoon continues.

A shortwave trough looks to move through the region on Tuesday,
bringing cloudy and cooler conditions with highs in the 60s across
the area. Low temperatures a touch cooler, in the mid to upper
40s. Best chances for showery precipitation will be through the
northern half of the region and along the Pacific Coast. The
Seattle area and the Southwest Interior has the best chances to
remain dry on Tuesday.

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...Deterministic and
ensemble model solutions generally in good consensus with the
upper level pattern evolution. Zonal flow will continue after the
trough departs on Wednesday, becoming a weak ridge on Thursday.
Thursday looks to be the warmest day in the period with
temperatures in the 70s region-wide. A larger trough will
approach the region Friday and dominate through the weekend,
bringing another period of below-normal temperatures and chances
for showers across the region.

LH


&&

.AVIATION...A weak upper level trough will move inland today for a
chance of showers and thunderstorms over the Cascades. The flow
aloft is westerly and will become more west-northwesterly tonight.
Satellite shows stratus has pushed inland along the coast and
into portions of the southern interior this morning, mainly
impacting KHQM and KPWT - though stratus may still make it into
KOLM for a few hours of reduced ceilings. Conditions for terminals
in stratus are generally MVFR to IFR. The majority of the interior
terminals will remain VFR, however, with a mix of mid and high
level clouds. Another round of stratus looks to move further
inland overnight, likely making it into the interior by early
Monday, for a few hours of MVFR ceilings.

KSEA...VFR today with S/SW winds 5-10kt. Low clouds and MVFR
conditions, along with light/variable wind, overnight toward
12Z Mon.


&&

.MARINE...High pressure will remain situated over the northeastern
Pacific with periods of northerly winds over the coast and
westerlies through the Strait of Juan de Fuca. Expect another
strong push of westerlies down the strait tonight - where a Gale
Warning is in effect.

Seas generally hovering between 8-9 ft across the coastal waters
this morning. Expect seas to gradually subside through the day and
back towards 4-6 ft by Monday. Seas are then expected to increase
towards 7-9 ft again on Tuesday.

33/14


&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Gale Warning from 5 PM this afternoon to 5 AM PDT Monday for
     Central U.S. Waters Strait Of Juan De Fuca-East Entrance
     U.S. Waters Strait Of Juan De Fuca.

&&

$$