Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
886
FXUS66 KSEW 260948
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
248 AM PDT Fri Jun 26 2026
.SYNOPSIS...
A weak frontal system will move inland across Western Washington
this morning. An upper level trough will then settle over the
region tonight into Saturday maintaining cool and unsettled
conditions. The trough will shift eastward later Sunday allowing
drier conditions to develop into Monday. Another system is
expected to drop southward into the area around the middle of
next week for continued cool temperatures and another chance for
showers.
&&
.SHORT TERM /TODAY THROUGH SUNDAY/...
A weak front will move onshore across the area this morning with
areas of light rain. Onshore flow will increase behind it for
breezy conditions around Puget Sound and through the strait.
This will allow a decent convergence zone to develop late this
afternoon into tonight. Some modest instability this afternoon
may lead to an isolated thunderstorm or two with CAPE values
generally 250 J/kg or less. The best chances for any thunder
(around 25 percent or so) will be in the convergence zone late
this afternoon and evening. The convergence zone should diminish
by Saturday morning as an upper trough settles over the region.
The trough will gradually shift southward across the area
through the day on Saturday keeping the threat of a few showers
in the forecast and holding temperatures a handful of degrees
below normal. By Saturday afternoon and evening, shower chances
will gradually become confined to the Southwest Interior and
higher terrain in the Cascades. The upper low is expected to
shift eastward into the northern Great Basin and Rockies on
Sunday allowing most of Western Washington to dry out. Heights
only recover modestly and low level onshore will remain in place
for continued cool conditions and plenty of cloud cover.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Model ensembles are in relative good agreement with keeping a
mean trough position along the west coast through much of next
week. They differ somewhat in minutiae as one might expect, but
the overall pattern favors continued cool, unsettled conditions
with perhaps another upper low dropping southward toward the
region mid to late week for additional light precip.
27
&&
.AVIATION...
Latest radar shows scattered showers moving across western
Washington. Intermittent rain showers will continue through the
morning becoming more isolated in the afternoon. Widespread LIFR to
MVFR conditions are currently being observed across the region.
Interior terminals are expected to generally remain MVFR this
morning with a 20-40% chance for IFR ceilings through 17Z. Coastal
terminals, including KPWT, have 50-80% chances of IFR conditions
(and 10-15% of LIFR) until 18Z Friday. A Puget Sound Convergence
Zone (PSCZ) is anticipated to develop in Snohomish County after 00Z,
bringing higher confidence for showers at KPAE Friday evening. There
is also a 15-20% for isolated thunderstorms for KSEA north and east
to the Cascades between 18Z Friday and 06Z Saturday. Best chances
will be with the PSCZ, but confidence is not high enough to include
in any TAFs. Southerly winds will largely prevail with gusts up to
20 knots this afternoon, except for KCLM where winds will be light
and variable.
KSEA...Predominantly MVFR conditions with ceilings expected to drop
below 2000 feet after 12Z with a 20-30% chance for IFR conditions
through 16Z. Light rain showers will continue on and off through the
morning with chances decreasing in the afternoon. Ceilings will
gradually improve to VFR in the late morning into the early
afternoon. Southerly winds 6-10 knots this morning increasing to 8-
13 knots with gusts up to 20 knots this afternoon. There is moderate
confidence (50% chance) for MVFR conditions to return after 06Z
Saturday.
&&
.MARINE...
A weak front will move inland early today. Onshore will
increase behind the front this afternoon into tonight with small
craft advisory winds expected in the central/east strait as well
as Puget Sound. Broad high pressure will remain centered well
offshore into midweek with lower pressure over the interior for
varying degrees of onshore flow. Increasing northwest flow will
lead to gusty winds and choppy seas out the outer coastal waters
this weekend into early next week.
27
&&
.FIRE WEATHER...
Main fire weather concerns revolve around a marginal lightning
threat today with thunderstorm probabilities around
15-20%...greatest around the convergence zone. Otherwise, cool
and unsettled conditions prevail over the next 7-days alongside
a very low lightning risk.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory from 3 PM this afternoon to 2 AM PDT
Saturday for Central U.S. Waters Strait Of Juan De Fuca-
East Entrance U.S. Waters Strait Of Juan De Fuca.
Small Craft Advisory from 11 AM this morning to 8 PM PDT this
evening for Puget Sound and Hood Canal.
&&
$$
NWS SEW Office Area Forecast Discussion