739
FXUS66 KSEW 272043
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
143 PM PDT Thu Jun 27 2024

.SYNOPSIS...Somewhat warmer conditions are expected Friday
followed by weak systems that will keep temperatures in check and
bring a slight chance of precipitation over the weekend. A
warming and drying trend is expected for the bulk of next week.

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY/...As of 130pm this afternoon
light popcorn showers were drifting across southwest WA while a
convergence zone and more widespread light rain were present
across the central Puget Sound northward into the north Cascades.
Shower activity will dissipate during the evening and overnight
hours and mostly dry conditions are expected Friday as weak,
transient ridging moves through the area. This will allow for
some breaks in the clouds on Friday and temperatures to warm back
into the upper 60s to low 70s. A very weak wave may bring a few
light showers to the northwest Olympic Peninsula and Cascades on
Saturday. This will be followed by yet another weak wave on
Sunday, resulting in slightly higher chances for light
precipitation. These systems will keep temperatures in check over
the weekend.

.LONG TERM /MONDAY THROUGH THURSDAY/...By Monday a weak system
will be exiting to the east allowing ridging to begin to develop
next week. This is likely to lead to warming and drying conditions
through the week. At this time, the July 4th holiday looks
relatively quiet, weather-wise, with temperatures most likely in
the 70s. Confidence begins to wane in the details by later in the
week when the 10th-90th percentile spread increases from 5-10
degrees Thursday to 15-20+ degrees Friday and beyond. At this time
there does not appear to be a strong signal for significant
weather impacts through the forecast period.
-Wolcott-

&&

.AVIATION...Flow aloft is becoming westerly/northwesterly behind a
trough located over and east of the Cascades. Lingering post frontal
showers continue across King/Snohomish counties and up into Whatcom
county. Convergence zone has brought VIS/CIGs down at KPAE
throughout the morning and afternoon to IFR/LIFR, and is expected to
continue until the convergence zone subsides later this
afternoon/evening. Remaining terminals are seeing CIGs improvements
to VFR/MVFR (although any shower that approaches any terminal will
likely bring conditions down to IFR briefly). Winds have become
variable with the convergence zone showers in Puget Sound (mix of
northerly and easterlies at or less than 6 kt) and will spread
southward from KPAE through the afternoon and evening towards
KSEA/KBFI/KPWT. Remaining areas will see south winds 8 to 12 kt
(couple gusts to 20 kt possible), becoming light overnight and
northerly at 5 kt by Friday afternoon. Patchy fog/low CIGs are
likely Friday morning, but will scatter out to VFR later in the day.

KSEA...CIGs and VIS have improved to VFR this afternoon. Any shower
that does hit the terminal will briefly reduce conditions to IFR.
Otherwise convergence zone activity continues to the north
(affecting KBFI as of early afternoon), and will slide down into
KSEA mid to late afternoon. Winds remain out of the south at 10 to
12 kt (with gusts to 20 kt). Shifting winds to the north/east are
possible as soon as 22-00Z through 06Z (via convergence zone). MVFR
will redevelop overnight before scattering out Friday afternoon.
Winds will become solidly northerly Friday afternoon.

HPR

&&

.MARINE...Onshore flow continues behind a surface trough/frontal
system that has largely passed through (although a few showers
remain ongoing through some of the inner waterways, some of which
may reduce visibilities to mariners in the East Strait of Juan de
Fuca and Puget Sound Waters). A push through the Central/East Strait
of Juan de Fuca this afternoon will produce gusty winds that may be
hazardous to small craft (up to 25 kt). Otherwise winds will remain
light for the majority of the period (occasional pushes through the
Strait of Juan de Fuca appear to remain below criteria for a small
craft advisory at this time). Expect seas to range from 4 to 6 feet,
potentially building to 6 to 8 feet by mid next week.

HPR

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 11 PM PDT this evening for Central
     U.S. Waters Strait Of Juan De Fuca-East Entrance U.S.
     Waters Strait Of Juan De Fuca.

&&

$$