Washington State Forecast Discussion

Western Washington


667
FXUS66 KSEW 260356
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
856 PM PDT Thu Apr 25 2024

.SYNOPSIS...Rain will turn to showers across Western Washington
tonight as a weakening frontal system moves across the area. A
few showers will remain into Friday as an upper trough remains
over the region. A series of fronts will maintain wet conditions
and below normal temperatures well into the coming week.

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY/...No changes were made to the
forecast this evening. The previous discussion can be found below
with updated aviation and marine discussions:

It's a damp and cool evening across Western Washington as a
weakening front moves into the area. Rain will turn to showers
overnight as a trailing upper trough moves onshore. Showers will
diminish by Friday afternoon into Friday evening as low amplitude
upper ridging pushes into the coastal waters. The ridge flattens
quickly by Saturday morning as the next in a series of fronts
arrives. Precip coverage will increase on Saturday, but the
overall QPF will be lighter than that of today. Another front
arrives Sunday afternoon into Sunday night. Snow levels in the
Cascades generally stay in the 4000 to 5000 foot range through the
weekend. With unsettled conditions in place, temperatures will
remain below seasonal norms throughout Western Washington.

.LONG TERM /MONDAY THROUGH THURSDAY/...The extended forecast
period begins much the same as the short term with another front
spreading precip across the area Monday into Monday night. More
uncertainty creeps into the day to day forecast details Tuesday
and beyond. The overall pattern remains unsettled heading into the
middle of next week as the mean trough position remains over the
Pacific Northwest. However, the flow is looking increasingly
zonal by that point in time. This results in considerable timing
differences amongst deterministic model runs as well as noteworthy
differences between the height anomalies in the ensemble means.
So, while it looks to remain unsettled, temperatures and PoPs may
begin to edge at least a little closer to seasonal normals by
late next week. 27

&&

.AVIATION...West southwesterly flow aloft becoming light Friday
morning as upper level trough stalls over Western Washington.
Light flow in the lower levels.

Ceilings mostly MVFR overnight with isolated IFR ceilings over
the Kitsap peninsula and along the coast. Local visibility 3-5sm
in light rain. Ceilings lowering Friday morning to low end MVFR or
IFR with local visibility 3-5sm in light rain. Slight improvement
Friday afternoon.

KSEA...MVFR ceilings with IFR ceilings at times 13z-17z. South
wind 4 to 8 knots becoming southwesterly Friday afternoon. Felton

&&

.MARINE...A low pressure system and associated cold front and
will continue to work its way through the region tonight into
Friday. Winds across the area will ease overnight. A weak surface
ridge will move through Saturday morning but will be quickly
followed by another front on Saturday afternoon. The active
pattern continues into next week with additional systems moving
through. While conditions will be breezy, widespread additional
headlines are not expected with winds staying around or just below
Small Craft Advisory thresholds.

The Small Craft Advisory will end for the East Strait of Juan de
Fuca and Admiralty Inlet early Friday morning.

Seas 6 to 8 ft at 10 s continue through the end of the week, rising
to 8 to 10 ft by Sunday and into the beginning of next week.

LH/Felton

&&

.HYDROLOGY...No river flooding expected in the next 7 days.
Rain along the south slopes of the OLympics overnight could push
the Skokomish River in Mason county close to action stage on
Friday. Felton/27

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 11 PM PDT this evening for Admiralty
Inlet-East Entrance U.S. Waters Strait Of Juan De Fuca.

&&