FXUS66 KSEW 052324
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
324 PM PST Tue Mar 5 2024

.SYNOPSIS...Generally dry conditions will prevail through Thursday
with high pressure building over the Pacific Northwest. Wet
conditions will return by the end of the week as a series of
troughs cross the region.

&&

.SHORT TERM /TONIGHT THROUGH FRIDAY/...A cool and dry airmass
will continue to push into western Washington from the north
today, allowing for mostly clear skies and light winds. While
temperatures will continue to stay well below normal, the lowlands
will see highs in the mid 40s.

A weak surface cold front will push inland overnight and into the
early morning, triggering light snow showers over the Olympic
Peninsula. Any accumulation is most favored over the eastern and
northern slopes of the Cascades, with a low (10 to 20 percent)
chance of up to an inch of snow over the San Juan Islands and far
western Whatcom and Skagit Counties through Wednesday morning.
Low temperatures will bottom out below freezing for all areas, so
areas of ice will once again be a concern around any heavier
showers that develop early Wednesday morning. Light shower
activity will continue through the afternoon before tapering off
as ridging builds inland into the Pacific Northwest.

A stacked low will amplify over the Gulf of Alaska towards the end
of the week, spreading a large moisture plume towards the Pacific
coast on Thursday and Friday. The majority of the moisture from
this system will be limited to the Olympic Peninsula through
Friday, but the lowlands and Cascades will see light shower
activity through Friday. Strong southerly flow aloft will allow
temperatures to warm up and return to normal by Friday.

.LONG TERM /SATURDAY THROUGH TUESDAY/...A series of much wetter
systems is on track to pass over the region over the weekend and
into next week, with temperatures hovering right around normal.
While deterministic models continue to show widespread heavier
precipitation holding off until Saturday, ensembles still bring in
the precipitation on Friday. Another wave of heavy precipitation
will quickly follow this initial push, with little to no time in
between for conditions to dry out. Forecast certainty decreases
beyond the weekend, but active and wet conditions are on track to
continue through the first half of next week.

&&

.AVIATION...Scattered to broken VFR ceilings this afternoon and
evening. Generally conditions should remain VFR with ceilings 4000
to 5000 feet tonight with local areas of shallow fog possible -
especially in sheltered valleys. Light northerly low level winds
will become more easterly but remain light.

KSEA...VFR conditions with scattered to broken ceilings 3500 to 4500
feet this afternoon. Ceilings are expected to remain in the 4000 to
5000 foot range after 06z. There is a 10% chance for shallow fog at
the terminal tonight, more likely it will form to the east and
possibly the north of the terminal. Light northerly winds around 4
to 6 knots becoming easterly around 06Z.

&&

.MARINE...Generally light winds and seas with northerly/offshore
flow into Wednesday. A weak system will affect area waters Wednesday
night followed by a series of systems starting Friday, with the
strongest winds - increasing southerly winds ahead of a front.
Active weather will linger into the weekend, with periods of winds
and building seas especially over the coastal waters.

&&

.HYDROLOGY...Strong, moist, S/SW flow will bring periods of heavy
rain along the Olympics and Cascades early next week with rising
rivers. Sharp rises are possible on the Skokomish River in Mason
County with flooding possible. 33

&&

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

$$