Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
405
FXUS66 KSEW 042134
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
234 PM PDT Thu Jun 4 2026
.SYNOPSIS...
Low pressure will drop out of the Gulf of Alaska tomorrow,
remaining offshore but generating potential for rain and
thunderstorms. The threat for thunderstorms expands on Saturday
as the low moves overhead and provides supportive upper level
dynamics. Cooler, cloudy, and at times showery weather will
persist into early next week before conditions begin to warm up
and dry out.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
Mostly cloudy across western Washington this afternoon with
highs so far in the mid 60s. Overnight into tomorrow, a deep
area of low pressure will move offshore out of the Gulf of
Alaska, sending a shortwave into the region. This will be the
driver of another round of showers and a few thunderstorms.
Tomorrow, the thunderstorm threat will be most likely within the
Olympic mountains and in areas of the north interior including
the North Cascades. Probabilities of thunderstorms range from
15% to 25% in these areas. The primary hazards will be
lightning, gusty and erratic winds, and periods of heavy rain
within the storms.
The aforementioned low pressure moves in directly overhead on
Saturday, providing supportive mid and upper level dynamics for
an expanded thunderstorm threat. Most unstable CAPE ranges from
300-400 J/kg, 0-6km lapse rates between 6-7 C/km, cold mid
levels, and easily achievable convective temperatures. Most of
the area, with the exception of the immediate coast and areas
north of Skagit County have around a 20-30% chance of seeing a
few thunderstorms throughout the day. The timing of thunderstorm
development and activity will largely be between 11AM and 7PM
local time. Please use caution when recreating and/or working
outside and remember to head indoors when thunder roars.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
Low pressure exits the region Saturday night, leaving Sunday in
more of a transitional pattern. Transient and weak high pressure
will fill in, only temporarily. Temperatures will be in the mid
60s, up a few degrees from Saturday. The bulk of the day should
remain cloudy, with chances for light showers arriving late in
the afternoon. Another round of low pressure arrives Monday for
more scattered showers and a slight chance of coastal
thunderstorms. This unsettled and cooler pattern lingers into
Wednesday before there is any indication of things warming and
drying. Temperatures warm slightly back into the low 70s by
Thursday.
The latest 8-14 day outlook from the CPC shows increased
confidence in above normal temperatures and below average
precipitation beginning late next week and heading into the
middle of the month.
21
&&
.AVIATION...
Westerly flow aloft will become southwesterly tonight as an upper
trough situated west of Haida Gwaii pushes a frontal system into the
region on Friday. Low level onshore flow is easing with VFR expected
for most areas into this evening. Ceilings will lower to MVFR along
the coast late tonight in increasing shower activity associated with
an incoming trough. These conditions will spread to interior
areas late Friday morning through the remainder of the day. The
air mass will become weakly unstable by Friday afternoon for
isolated thunderstorm activity.
KSEA...VFR conditions will continue into tonight. There`s a less
than 20% chance of MVFR ceilings early Friday with ceilings more
likely to lower after 18Z-20Z as shower activity ramps up with the
next frontal system. Surface winds will veer northwesterly 5 to 8
knots for a few hours late this afternoon and early evening before
backing southerly again overnight and rising to 9 to 14 knots Friday
AM.
27
&&
.MARINE...
Onshore flow will ease today as a weak surface ridge shifts inland
and a broad surface low drops southward in the offshore and coastal
waters. A weak front will cross the waters midday Friday into Friday
afternoon. A vertically stacked trough trailing the front will move
onshore during the day on Saturday with relatively little impact in
terms of wind. A weak surface ridge will cross the waters Saturday
night into Sunday before another frontal system reaches the area
Sunday night and Monday with potential headlines for the coastal
waters. Coastal seas look to remain below 10 feet through the
period.
27
&&
.FIRE WEATHER...
Onshore flow has been beneficial to most areas of western
Washington, yet afternoon RH values are still only in the 40%
range for areas from Seattle south. The ERCs will respond to the
increase in moisture over the next several days, especially in
the fine fuels. Friday and Saturday will feature area wide
chances for thunderstorms, but indications are looking more
favorable for them containing adequate QPF. The pattern turns
warmer and drier toward the end of next week, lasting beyond
the middle of the month, so fire weather conditions will
continue to be evaluated as that pattern evolves.
21
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 11 PM PDT this evening for Central
U.S. Waters Strait Of Juan De Fuca-East Entrance U.S.
Waters Strait Of Juan De Fuca.
&&
$$
NWS SEW Office Area Forecast Discussion