552
FXUS66 KSEW 181547
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
847 AM PDT Tue Jun 18 2024

.SYNOPSIS...High pressure aloft will gradually build through the
week, allowing conditions to dry out and warm up. A pattern change
is on track for the weekend as a trough brings wetter and cooler
conditions to western Washington.

&&

.SHORT TERM /TODAY THROUGH THURSDAY/...A few showers remain
offshore based on latest radar imagery, but should dissipate this
morning. High pressure will continue to build inland through the
short-term, allowing clouds to scour out throughout the day today
and allow temperatures to warm up. Lingering moisture over higher
terrain may result in a few stray showers, especially over the
Cascades this afternoon, but will result in little to no
additional accumulations. Onshore flow will help to moderate
temperatures along the Pacific coast, while many inland areas will
warm up significantly, reaching the mid 70s for most, approaching
80 through the Southwest Interior and Cascade valleys on
Wednesday, with more widespread highs in the 80s by Thursday.

.LONG TERM /FRIDAY THROUGH MONDAY/...Despite continued moderated
temperatures along the coast, inland areas will see a warming
trend to continue into Friday with potential to see the warmest
day of the year so far. Temperatures across the lowlands are on
track to peak in the low to mid 80s on Friday, which may generate
localized areas of urban heat stress for vulnerable populations in
the Seattle, Tacoma, and Olympia metro areas. However, low
temperatures in the 50s will provide relief for the heat ahead of
a pattern change.

A deepening trough along the Pacific Northwest coast will
increase cloud cover on Saturday, causing temperatures to lower a
few degrees across western Washington. A frontal system is on
track to slide across the region late Saturday into early Sunday,
bringing cooler temperatures, another round of showers, and breezy
winds. Temperatures Sunday and Monday will lower a few degrees
below normal into the mid 60s, with ensembles maintaining a chance
of precipitation across the region. Long-range rainfall forecasts
show relatively light amounts with this system with no significant
impacts expected through the forecast period.

Lindeman/LH

&&

.AVIATION...Northerly flow aloft will continue for much of the day
today before turning northwesterly this evening. Surface winds
trending southerly with speeds mostly less than 5 kts. These winds
will shift more westerly in the late morning before turning
northerly in the afternoon. Speeds will increase, but remain around
4-8 kts.

W WA socked in with low clouds this early morning with stratus
leading to MVFR conditions along the coast and around the Sound.
Conditions will start to improve late this morning with
widespread VFR conditions expected into afternoon. Skies will
continue to clear out in the afternoon and evening, with only high
clouds expected after 00Z late this afternoon. Of course,
locations that typically see lower cigs may not clear out
completely, but cigs will remain VFR.

KSEA...MVFR conditions in place throughout late morning. AOA 17Z,
should start to see conditions improve to VFR with a gradual
clearing throughout the afternoon. Only high clouds expected after
00-02Z with VFR conditions expected overnight. Southerly winds at
the time of this writing 4-8 kts will turn westerly late in the
morning, then northerly in the early afternoon and remaining there
for the rest of the TAF period. Speeds will remain generally
unchanged.

18/Mazurkiewicz

&&

.MARINE...Broad high pressure is centered just offshore in the NE
Pacific and will dominate the pattern into this weekend. Occasional
pushes down the Strait still appear to be on tap during this time
frame, however at the time of this writing models suggest that
speeds will not reach headline criteria for the remainder of the
week. A frontal system will approach the waters this weekend
bringing showers, but again winds do not appear to be of concern
with the frontal passage. However, additional pushes down the Strait
beginning Sunday may require headlines.

Seas remain 4 to 6 ft through the remainder of this week, rising to
6 to 8 ft beginning this weekend.

18

&&

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

$$