Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
540
FXUS66 KSEW 271028
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
328 AM PDT Mon Apr 27 2026
.SYNOPSIS...
Upper level ridge along British Columbia coast with low level
onshore flow through Tuesday giving Western Washington mostly
cloudy and cooler weather. Upper level ridge moves over the area
Wednesday then slides east Thursday. Weak upper level trough
moving through Thursday night. Upper level ridge building to the
northwest with an upper level low developing well west of
California Friday through the weekend with temperatures warming
into Sunday.
&&
.SHORT TERM /TODAY THROUGH WEDNESDAY/...
Satellite imagery shows stratus west of the Olympics, over the
Southwest Interior and at 3 am/10z starting to fill up the
Central Puget Sound area. Mostly clear skies elsewhere.
Temperatures with the cloud cover were warmer than the previous
mornings, in the 40s and lower 50s.
Marine push ongoing this morning. Stratus will continue to fill
in over the Central Puget Sound through sunrise with the stratus
getting as far north as Skagit county. No top reports yet this
morning but the Black Hills in Southwest Washington are covered
so tops at least 3000 feet and probably a little higher.
Continuing onshore flow through the day combined with the
thickness of the marine layer will keep skies cloudy this
morning before somewhat of an afternoon breakout over the
interior. Skies remaining cloudy along the coast with light
showers or drizzle possible this morning. Cooler today with
highs in the mid 50s to lower 60s.
Little change in the pattern tonight into Tuesday with low
level onshore flow. Marine layer returning to the interior
overnight for another cloudy start to the day. Low level flow
going light in the afternoon but cross Cascade gradients still
around plus 6 mb late in the afternoon. This will make it hard
for a complete clear out of the stratus over the interior. Will
word the forecast mostly cloudy. Highs again in the mid 50s to
lower 60s. Lows Tuesday morning in the 40s.
Upper level ridge along the British Columbia coast today into
Tuesday morning moving over Western Washington Tuesday night
into Wednesday. Low level flow going light northerly Wednesday
with cross Cascade gradient trending towards zero. This will
thin out the marine layer. Plenty of sunshine Wednesday with
highs back into the lower to mid 60s. Lows Wednesday morning in
the mid 30s to mid 40s. Felton
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Upper level ridge over the area Wednesday night moving east
Thursday. Weak upper level trough sliding through Thursday night
with another upper level ridge rebuilding Friday. Models
continuing to have trouble latching on to a solution for Friday
night through the weekend. Latest solution has an upper level
block forming offshore over the weekend with north northeasterly
flow aloft and the low level flow turning offshore.
Highs Thursday in the 60s and lower 70s, cooling a little Friday
into the 60s then warming over the weekend to the mid 60s to mid
and upper 70s by Sunday. Current model blend has a high of 74
for Seattle Sunday. About a quarter of the solutions have the
high in the upper 70s. Normally in May a high in the upper 70s
would not be a record in Seattle. 30 out of the 31 days in May
have a record high of 82 degrees or warmer. The one day that
does not, May 3rd with a record high of 77. Outside chance of
setting a record Sunday. The average first 80 degree plus day in
Seattle is May 20th. The earliest April 1st, 1987 ( 82 degrees )
and the latest July 21, 1980 ( 85 degrees. Something happened in
1980 that caused this late date ). Felton
&&
.AVIATION...North to northwesterly flow aloft continues through the
TAF period with troughing over the interior West and upper ridge
offshore. Onshore flow this morning is resulting in stratus
spreading into the interior. Predominantly MVFR (areas of IFR) cigs
has been observed this morning. Cigs will slowly improve into VFR
around 18-22z Monday afternoon for interior locations, with MVFR
continuing along the coast. More widespread MVFR cigs are in the
forecast overnight Monday into Tuesday. Southerly winds 8-12 kt with
gusts around 20 kt for interior terminals.
KSEA...MVFR ceilings have developed this morning and will remain
through 18-20z before improvements to VFR in the afternoon. There
also remains approximately a 30% probability of IFR cigs, peaking
between 10 to 15z Monday. S/SW surface winds through the TAF period
ranging between 5 to 10 kts with gusts near 20 kt possible this
morning and during the afternoon. More MVFR cigs likely to develop
overnight into Tuesday.
41
&&
.MARINE...
High pressure continues over the coastal waters, with lower pressure
inland. Onshore this week with weak pushes through the Strait of
Juan de Fuca. The strongest push in the guidance is Monday evening,
but the probability of winds exceeding 20 kt remains low. Low
ceilings in the coastal waters Monday morning (with pockets of fog)
may lower visibilities at times to mariners. The next potential
system may bring breezy winds over the coastal waters around Friday.
Seas for Sunday hold around 4-6 ft, and increase to 6-9 ft for the
remainder of the week.
41
&&
.HYDROLOGY...
No river flooding in the next 7 days.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...None.
&&
$$
NWS SEW Office Area Forecast Discussion