Spanaway, Washington Weather Forecast Discussion

347
FXUS66 KSEW 281056
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
356 AM PDT Sun Sep 28 2025
.SYNOPSIS...A frontal system will move through Western Washington
Sunday afternoon into Monday that will bring widespread rain to the
region. Unsettled conditions are expected to continue throughout the
week as additional frontal systems push through the region. Breezy
to gusty winds expected throughout the week with the frontal
systems.
&&
.SHORT TERM /TODAY THROUGH TUESDAY/...Radar is pretty quiet this
morning with a few light showers moving to the northwest of Western
Washington. Expecting Sunday morning to remain relatively dry. A
frontal system will bring widespread rain Sunday afternoon into
Monday. Rain is expected to first reach the coast and Olympic
Peninsula Sunday afternoon and then fill in into the interior by
early Monday morning, with rain continuing throughout the day.
Breezy to gusty winds also accompany this system. This system will
also bring breezy to gusty winds to the region. The strongest winds
will be along the coast, northern interior, and Strait of Juan de
Fuca, with high confidence (70-90%) of wind gusts exceeding 25 mph.
There is medium confidence (50-60%) in gusts exceeding 30 mph at the
coast and medium to high (50-75%) confidence for the northern
interior. Rainfall accumulations for the lowlands range from 0.20-
0.75 inches and for the coast accumulations range from 1.00-2.00
inches. There is also a slight chance of thunderstorms Sunday
evening along the coast (10-20%) and Monday evening for the lowlands
and Cascades (10-15%).
A stronger system will push through the region Tuesday into
Wednesday. This system will bring higher rainfall totals to the
region. Breezy to gusty winds are also expected with this system.
There is high confidence (70-90%) of seeing wind gusts exceed 25 mph
along the coast, Strait of Juan de Fuca (west and east portions),
and northern interior. There is also the potential to see gusts
exceed 30 mph along the coast and northern interior (60-80%).
Guidance is also showing a slight chance of thunderstorms for
Tuesday and Wednesday afternoon. Tuesday`s chances are around
10-15%, while Wednesday has a slightly higher chance at 15-25%.
Temperatures will gradually decrease throughout the week. On Sunday
high temperatures will be in low to mid 70s in the interior and low
to mid 60s along the coast. By Tuesday temperatures in the interior
will be in the mid to upper 60s and at the coast in the low 60s.
.LONG TERM /WEDNESDAY THROUGH SATURDAY/...As the aforementioned
frontal system pushes through Western Washington on Wednesday, the
parent upper low pressure system will linger offshore. There is
uncertainty regarding the exact path the low pressure system will
take on Thursday. One solution has the center of the low pressure
pushing through Western Washington, while another solution has the
low pressure system moving south towards the Oregon/California
border. If the low pressure center moves into Western Washington,
guidance supports unsettled conditions to continue late in the week.
However, if the low tracks further south it may open the opportunity
for weak ridging over the region and drier conditions.
29
&&
.AVIATION...Flow aloft will become more southwesterly through the
day as an upper low digs over the Gulf of Alaska. Current conditions
across the area terminals are primarily VFR this morning, with
the exception of IFR/LIFR conditions for coastal terminals in
stratus and a few spots of fog across the interior. IFR conditions
may persist along the coast through much of the day, with VFR
conditions expected to persist across the majority of the interior
terminals. Mid to high level cloud cover will continue to stream
across the region through the day. A frontal system will move
across the area late tonight into Monday, bringing the next round
of rain to the region. Light showers will start to move inland
along the coast tonight, with more widespread rain moving inland
early Monday. Winds will primarily be out of the S/SW at 5-10 kt
today and will increase along the coast between 06-08Z Monday,
with gusts to 25 kt possible.
KSEA...VFR conditions with light northerly winds between 3-6 kt.
Winds will shift to the SW likely between 18-21Z and increase to
5-10 kt.
14
&&
.MARINE...A frontal system will move across the area waters
tonight into Monday, bringing gusty southerly winds to the region.
Winds will start to increase across the coastal waters later this
morning and across the interior waters late tonight. Winds will
primarily range between 20-30 kt, though some gusts may briefly
exceed 35 kt at times, especially within the vicinity of the
front. With an increase in winds, will see seas build to 10-12 ft
across the coastal waters this afternoon and evening.
A stronger frontal system will move across the area waters
Tuesday into Wednesday, likely bringing gales to the coastal
waters, the Eastern Strait of Juan de Fuca, and portions of the
Northern Inland Waters. Current probabilities show a 60-80 percent
chance of gusts reaching 34 kt across the coastal waters and
roughly a 35-45 percent chance across the eastern Strait.
Seas across the coastal waters will build between 15-18 ft.
Winds and waves will decrease again heading into Thursday as the
low pressure system sinks southward along the coast and weakens.
High pressure will build over the northeast Pacific again late in
the week, shifting winds back to the northwest over the coastal
waters.
14
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory from 8 PM this evening to 11 AM PDT Monday
     for East Entrance U.S. Waters Strait Of Juan De Fuca-
     Northern Inland Waters Including The San Juan Islands.
Small Craft Advisory until 5 AM PDT Monday 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.
&&
$$

NWS SEW Office Area Forecast Discussion