991
FXUS66 KSEW 261252
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
452 AM PST Thu Feb 26 2026
.SYNOPSIS...
A disturbance will continue across the area with additional
snow for the mountains and lowland rain showers through Friday.
A trend towards drier conditions emerge over the weekend and
continue into the first half of next week before the next front
arrives around midweek.
&&
.SHORT TERM /TODAY THROUGH SATURDAY/...
The upper-level pattern has remained fairly unchanged the last
24 hours or so. A cut off low continues to meander over the NE
PAC in concert with a ridge nosing into the Bering Sea.
Downstream of the low center, additional ridging is extending
off the US West coast as its axis parallels the CA coast. In the
midst of this complicated wave pattern, the PNW is in the regime
of WNW flow aloft, serving as a conduit for lowland rain showers
and mountain snow.
For today, rain showers are in the forecast along the coast and
windward Olympic Peninsula. A few may sneak into the W WA
lowland interior but rain shadowing will help to keep them at
bay. Mountain snow will persist for the Cascades & Olympics
with snow levels around 2,500 to 3,000 ft. Breezy southerly
winds with gusts up to 30-35 mph are also in store with the
strongest expected for areas adjacent to Puget Sound, San Juans
and W Whatcom. A frontal system over interior BC will interact
with a surface high positioned just off the Oregon Coast -
highlighted well on the Olympia - Bellingham gradient analysis.
This pattern will likely remain through Friday. An additional
5-10" of snow is in the forecast for the North Cascades
including Mt. Baker Ski area. 850mb flow will turn more zonal
here as well. As a result, high-res model reflectivity is
picking up on convergence zone activity over the Puget Sound
region. This feature will increase PoPs for lowland locations
of the interior but only for Snohomish county and adjacent
areas.
Signs of pattern progression into Saturday as the aforementioned
low center becomes ingested in the mean-flow. Here, it`ll loom
just off the CA/OR coast with upper-level ridging over the Gulf
of Alaska. Conditions will dry out and trend that way into next
week. High temperatures are to top out in the upper 40s to near
50 F with overnight lows cooling lower into the 30s each night.
A 40-60% chance of overnight lows dropping below 32 F
throughout the Chehalis River valley along with a 30-40% chance
for W Whatcom lowlands by Saturday morning.
McMillian
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
Ensembles suggests the upper-level pattern will continue to progress
in the long-term forecast. The aforementioned cut off low will
track inland over N. California/S. Oregon on Sunday. An upper-
ridge will gradually position over the PNW by early next week.
Daytime highs are slated to remain around average with cool
overnight lows in the lower to mid 30s. The next front looks to
arrive around midweek with a chance of widespread lowland rain
and mountain snow.
&&
.AVIATION...
West to northwest flow aloft continues through Thursday
with zonal flow. VFR to MVFR cigs continue across Western
Washington early this morning. Cigs will generally fluctuate between
low end VFR to MVFR into the afternoon, with primarily VFR this
evening. Cigs will then lower again tonight into Friday morning.
Precipitation will mainly be confined to the mountains and north
coast today, but light rain may be observed at times elsewhere,
mostly for the northern terminals. South to southwest surface winds
will remain breezy through today, with gusts ranging between 15 to
25 kts, and localized gusts to 30 kt.
KSEA...VFR conditions continue early this morning with low end VFR
cigs. Cigs may lower into MVFR at times into the afternoon, with the
best chance between 15 to 21z. Otherwise, low end VFR expected.
South to southwest surface winds through today with gusts near 25
kt. JD
&&
.MARINE...
Moderate onshore flow continues through Friday with lower
pressure over British Columbia and high pressure located around the
NE Pacific. Small Craft Advisory south to southwest surface wind
gusts will continue into this morning for the Coastal Waters before
slowly dissipating later today. SCA southwest to west winds are also
expected through the Strait of Juan de Fuca. Onshore flow will also
result in periodic SCA gusts for the northern inland waters and Puget
Sound through the afternoon. Otherwise, winds will ease on Friday as
high pressure builds over the waters. Northerly surface winds return
over the weekend.
Seas will range between 7 to 9 feet today, before building to 8 to
11 feet tonight through Friday. Seas will then subside to 6 to 8
feet on Saturday. JD
&&
.HYDROLOGY...
No river flooding is expected during the next seven days.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Winter Weather Advisory until 4 AM PST Friday for Cascades of
Snohomish and Northern King Counties-Cascades of Whatcom
and Skagit Counties.
PZ...Small Craft Advisory until 4 PM PST this afternoon for Central
U.S. Waters Strait Of Juan De Fuca-West Entrance U.S.
Waters Strait Of Juan De Fuca.
Small Craft Advisory until 6 PM PST this evening for Northern
Inland Waters Including The San Juan Islands-Puget Sound
and Hood Canal.
Small Craft Advisory until 10 AM PST 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.
&&
$$
NWS SEW Office Area Forecast Discussion
