199
FXUS66 KSEW 181723
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
1023 AM PDT Wed Sep 18 2024

.SYNOPSIS...


&&

.SHORT TERM /TODAY THROUGH FRIDAY/...Lingering low clouds and some
light drizzle across Western Washington this morning. Still expect
gradually scattering clouds into the afternoon, and no significant
updates required to the forecast this morning.       12

Showers shifting south today as a trough digs over the West.
Onshore flow prevails across western WA with plenty of low clouds
over the lowlands. High pressure tries to nudge inland this
afternoon with a few sunbreaks possible. Temperatures remain a few
degrees cooler than average and in the 60s.

Thursday`s weather looks dry but we`re still under the influence
of NW onshore flow for partly to mostly cloudy skies. The interior
may see a few showers on Friday where there`s convergence. Highs
in the 60s both days with lows in the 40s and 50s. 33

.LONG TERM /SATURDAY THROUGH TUESDAY/...There`s more wet weather
heading into the weekend with W to NW flow aloft, especially by
Sunday. By then, the next disturbance will roll through western WA
with rain spreading through the region. Wetting rains expected in
the mountains. Moving forward, high pressure shifts inland,
deflecting precip to the north or near the Canadian border.
Temperatures rebound with highs reaching the 70s again. 33

&&

.AVIATION...North to northwest flow aloft will increase over
Western Washington today as upper level ridging gradually rebuilds
into the region behind a departing trough. Low level moisture
remains in place with widespread IFR or low MVFR ceilings. With
light low level flow, these conditions will be slow to improve.
Ceilings will gradually lift to VFR away from the coast 21Z-00Z.
Continued relatively light surface flow favors the redevelopment of
IFR or low MVFR conditions in stratus/fog across the lowlands of
Western Washington again on Thursday morning.

KSEA... Bouncing IFR/MVFR ceilings in stratus will gradually lift
to MVFR around 19Z before becoming lower end VFR 22Z-00Z.
Ceilings are likely to sink down again tonight with low MVFR or
tempo IFR expected by daybreak Thursday. Surface winds
north/northwesterly 5 to 8 knots through this afternoon. Winds
look to lighten up this evening into Friday morning. 27/Mazurkiewicz

&&

.MARINE...A weak surface low over the southern Oregon coastal waters
will continue to shift southward today as a broad surface ridge
centered well offshore expands into the Washington coastal waters. A
weak surface trough in the vicinity of Vancouver Island later
Thursday into Friday will likely tighten the northwesterly gradient
enough to produce some small craft advisory conditions over the
outer coastal waters in the form of gusty winds and steep seas.
Otherwise, relatively tranquil conditions are expected across the
remainder of area waters heading into the upcoming weekend. 27

&&

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

$$