950
FXUS66 KSEW 241011
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
311 AM PDT Wed Apr 24 2024

.SYNOPSIS...Weak front moving inland today. This will mark the
beginning of a cool and wet last week of April with an upper level
trough over the area and a couple of systems moving through over
the weekend and Monday. Snow levels will lower over the weekend to
near 2500 feet Monday for possible snow on all the mountain
passes the first part of next week.

&&

.SHORT TERM /TODAY THROUGH FRIDAY/...A pattern change brings
cooler and wetter weather back to western WA starting today. This
is due to an upper low moving through B.C. while dragging a weak
front over the region. KLGX is picking up on light rain along the
coast this morning. Rain will spread into the interior this
afternoon with light amounts expected - trace to 0.05" along I-5.
With onshore flow and cloudier conditions temperatures will track
closer to average and in the 50s.

Wet weather continues on Thursday with an upper level trough
crossing the area. Precipitation totals, overall, are greater
compared to Wednesday with measurable rain expected across all
lowlands.

Showers linger into Friday with a deep trough across the West.
Widespread measurable rain is expected again across the area.
Three-day rainfall totals are around 0.50-1" in the interior with
1-2" along the coast. Snow levels are around 4500` for mainly
rain at the Cascade highway passes. 33

.LONG TERM /SATURDAY THROUGH TUESDAY/...Upper level troughing over
the Pac NW continues into this weekend for more rain and (high
elevation) mountain snow. There`s little break in the action with
a pair of frontal systems pushing inland, thus maintaining moist
S/SW flow over the area. A deep upper low wobbles overhead as we
move into next week, keeping the air mass cool and showery. Lows
will track cooler than average and in the mid to upper 30s to
lower 40s. The cool spots will be over the south sound. Highs will
also be a few degrees below average and in the mid 50s. Snow
levels will lower to around 2500` on Monday and the mountain
highway passes may see a few inches of snow. Overall, a cool and
wet end to the month. 33

&&

.AVIATION...Winds W/SW aloft as an upper-trough builds in. Surface
winds are variable right now, but should trend out of the W/SW as
the morning progresses. Mostly VFR this morning but MVFR (with
isolated IFR) is building along the coast ahead of a weak frontal
system. Cigs are to lower with a mix of VFR and MVFR likely across
interior airfields later this morning and into the afternoon. As far
as precipitation goes, showers are to be scattered in nature. A
brief return to VFR is possible into the evening for some but cigs
may lower again ahead of an additional disturbance late overnight
into Thursday.

KSEA...Mostly VFR conditions expected through the TAF period but, a
20-40% chance of lowering to MVFR is possible at times later this
morning and into the afternoon. Higher confidence in VFR returning
towards the evening but more MVFR is possible late overnight ahead
of a disturbance entering on Thursday.  Winds transitioning to light
southerly this morning before turning SW between 5-10 kt. A few
showers are possible but should be light and not impactful today.

McMillian

&&

.MARINE...A weak frontal system is approaching the area from the
northwest. Winds through Strait of Juan de Fuca are still at SCA
levels but should weaken later in the morning as onshore flow
diminishes. A more substantial system will move through the area
waters on Thursday. Some uncertainty remains in the extent of its
wind field but decided to issue a SCA for the southern most zones of
the outer and inner coastal waters where gusts will meet thresholds
at the very minimum. A weak surface ridge will momentarily ease
wind speeds for Saturday before an active pattern re-emerges Sunday.

Seas look to remain 4 to 6 feet at about 10 seconds through the rest
of the week and into Saturday.

McMillian

&&

.HYDROLOGY...No river flooding expected in the next 7 days.
Heavier rain over the south slopes of the Olympics Thursday and
Thursday night could push the Skokomish River in Mason county
close to action stage Friday. Felton

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 6 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.

     Small Craft Advisory from 5 AM to 5 PM PDT Thursday for Coastal
     Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm-
     Coastal Waters From Point Grenville To Cape Shoalwater Out
     10 Nm.

&&

$$