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000
FXUS66 KSEW 150902
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
202 AM PDT Mon Apr 15 2024

.SYNOPSIS...
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Upper-level troughing returns on Monday with showers
and cooler temps. Then, ridging will rebound around midweek with
the potential for more warmer and drier weather followed by the
potential for a weak frontal passage over the weekend.
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.SHORT TERM /TODAY THROUGH WEDNESDAY/...
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Near-zonal flow aloft as
we`re transitioning from weak ridging to upper-level troughing.
The weekend`s above normal temperatures and dry weather will come
to an end on Monday. The main feature will be convergence zone
activity through much of central Puget Sound today and tonight.
However, scattered showers are to also track across western
Washington and given current hi-res guidance they appear to be
rather hit or miss. Light rainfall amounts are expected but
locations in and around the convergence zone could see up to 0.25
to 0.50" in the foothills and higher elevations with locally
higher amounts possible. Snow levels will also start off around
3,000 ft before falling to 2,000 ft tonight. With that, a few
inches of snow won`t be hard to achieve at the passes. Noticeably
cooler highs are in the forecast with lower to mid 50s expected
with overnight lows in the mid 30s to lower 40s.

Lingering showers and cooler temperatures will linger into
Tuesday. However, most showers will be in and around the confines
of the mountains given orographic enhancement. But, we`ll begin
to trend much drier on Wednesday as troughing progresses and
upper-level ridging builds over the NE pacific. Because of this,
not only will we see drier weather but highs will increase with
mid 50s to lower 60s expected.

.LONG TERM /THURSDAY THROUGH SUNDAY/...Conditions are
continuing to trend drier Thursday and Friday. Deterministic
guidance continues to hint at a ridge amplifying near the region.
But, questions remain on its exact location and intensity.
Nevertheless, the brief cool down to start the week on Monday may
not last too long as temps could possibly top out in the upper 60s
on Friday. Ahead, much uncertainty is present this far out, but a
weak front could brush the area over the weekend.

McMillian
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.AVIATION...
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Mainly VFR to MVFR with increasing high and mid-level
clouds and low stratus over Grays Harbor. Westerly flow aloft as a
cold front dig southward across western Washington through the early
morning. Ceilings will continue to lower this morning with a 30%
chance of MVFR ceilings persisting over the Puget Sound terminals
through 20z. Scattered light rain showers and drizzle likely much of
the day today and tonight as a convergence zone with enhanced shower
activity and brief wind shifts sets up east of the Puget Sound.

KSEA...MVFR conditions with a thickening cloud deck near 2500 ft.
South winds at the surface are favored to shift to the E/NE after
19z as a convergence zone and enhanced shower activity develops. The
exact placement of the convergence zone is still uncertain, but
models favor the development this afternoon in southern King
County/northern Pierce County. Winds may shift more northerly as the
track of the convergence boundary shifts north/south. Best timing
for this potential northerly wind shift looks to be in the 20-03Z
timeframe this afternoon and evening.

Lindeman
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&&

.MARINE...
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A cold front continues to dive south across the area
waters early Monday morning. Onshore flow continues, with gales
through the Central and East Entrance to the Strait of Juan de Fuca
until at 3 AM. Small Craft Advisories remain in effect through 11 AM
Monday across the coastal waters and West Entrance to the Strait.
Winds will briefly ease through the morning with Gales being
downgraded to Small Craft Advisories before they quickly pick up
again Monday afternoon. A Gale Warning has been issued for the
Central and East Strait along with Admiralty Inlet Monday afternoon
through early Monday night, along with a Small Craft Advisory for
the West Entrance and northern coastal waters.

Seas from 7 to 9 feet will increase closer to 10 feet Monday morning
over the coastal waters before gradually lower back to 7 to 9 feet
through the day Monday. Seas continue to lower through the week,
trending below 5 feet Thursday and Friday.

Davis/Lindeman
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&&

.HYDROLOGY...No river flooding is expected through the next seven
days.


&&

.SEW WATCHES/WARNINGS/ADVISORIES...
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WA...None.
PZ...Small Craft Advisory until 11 AM PDT this morning for Coastal
     Waters From Cape Flattery To James Island 10 To 60 Nm-
     Coastal Waters From Cape Flattery To James Island Out 10 Nm-
     Coastal Waters From James Island To Point Grenville 10 To
     60 Nm-Coastal Waters From James Island To Point Grenville
     Out 10 Nm-Coastal Waters From Point Grenville To Cape
     Shoalwater 10 To 60 Nm-Coastal Waters From Point Grenville
     To Cape Shoalwater Out 10 Nm-West Entrance U.S. Waters
     Strait Of Juan De Fuca.

     Gale Warning until 3 AM PDT early this morning for Central U.S.
     Waters Strait Of Juan De Fuca-East Entrance U.S. Waters
     Strait Of Juan De Fuca.

     Gale Watch from this afternoon through late tonight for Central
     U.S. Waters Strait Of Juan De Fuca-East Entrance U.S.
     Waters Strait Of Juan De Fuca.

     Small Craft Advisory until 3 AM PDT early this morning for
     Admiralty Inlet.

     Gale Watch from this afternoon through late tonight for
     Admiralty Inlet.
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&&

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