816
FXUS66 KSEW 290247
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
747 PM PDT Fri Jun 28 2024

.SYNOPSIS...A weak shortwave will bring in increased cloud cover
and light showers this evening. Another frontal system will cross
western Washington on Saturday, bringing in another round of
showers. Unsettled and cloudy weather will linger into Monday
morning before high pressure offshore allows conditions to dry out
and slowly warm up through the end of next week.


&&

.SHORT TERM /TONIGHT THROUGH TUESDAY/...No major changes to the
forecast have been made this evening. The rest of the previous
discussion can be found below with an update to the aviation and
marine sections.

A front will swing through the region throughout the day Saturday,
with additional light shower chances confined mainly to the
Olympics and higher terrain in the North Cascades. While much of
the lowlands will see little more than cloudy skies and some
occasional sprinkles, the mountains will see light accumulations
of a few hundredths. Temperatures will return to near normal for
late June with highs in the mid 70s across the lowlands.

Shower chances will taper off Sunday, leading us into a drier
upcoming period with a ridge building offshore. High resolution
models continue to hint at the possibility of convergence zone
shower activity developing along the King/Snohomish County line,
though the exact track and intensity of any convergence zone
showers is uncertain. Cloudy skies with periodic breaks will
persist for much of the region on Sunday as onshore flow
continues.

Northwest flow aloft will maintain somewhat cloudy skies on
Monday, with a slight chance for showers lingering over the
mountains. Otherwise, Monday will be the last day of spring-like
weather ahead of a pattern change on tap for the rest of the
week.

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...Models in good agreement
with a warming, drying trend throughout next week as an upper
level ridge shifts onshore Monday into Tuesday. A weak shortwave
will influence the region Tuesday night into early Wednesday
morning, with shower chances minimal and temperatures increasing
several degrees above normal. The ridge axis will cross over the
region on Thursday with high pressure dominating the weather
pattern into next weekend. The warmest days will likely come late
in the extended period as we`ll see a 50-60% chance of exceeding
80 degrees for the lowlands going into next weekend.

Shepard/Lindeman


&&

.AVIATION...Southwesterly flow aloft this evening into Saturday
afternoon in advance of an incoming shortwave trough. Persistent
onshore flow continues to result in most obs sites seeing surface
winds mostly westerly or northwesterly with speeds generally ranging
4 to 8 kts.

VFR conditions in place over W WA this evening with only mid to high
level clouds in place over the area. Cigs in the majority of
terminals will lower somewhat tonight, however all cigs are expected
to remain VFR. Locations prone to low clouds may see some SCT clouds
develop around 2000-3000 ft, but confidence is low they will be
impactful.

KSEA...VFR conditions throughout the TAF period, even though cigs
may lower a little bit after 06Z. Winds this evening remaining
northwesterly before becoming light and variable overnight. Westerly
surface winds around 5 kts expected Saturday afternoon.

18


&&

.MARINE...A weak system will pass over the waters this weekend, but
no hazards are expected with this push as wind speeds remain under
any headline thresholds. Once this system passes through, pushes down
the Strait will resume their daily pattern, however, again, wind
speeds will remain below 20 kts.

Seas of 3 to 5 feet will build to 4 to 6 feet Sunday through Tuesday
before increasing again Wednesday and Thursday to to 6 to 8 feet.

HPR/18


&&

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

$$