Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
483
FXUS66 KSEW 300324
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
824 PM PDT Tue Sep 29 2026
.SYNOPSIS...A frontal system will move out of Western Washington
into this evening. High pressure builds aloft over the Pacific
Northwest Thursday and Friday, with just a slight chance of
precipitation. The upper ridge further builds over the weekend
for drier, warmer conditions.
&&
.SHORT TERM /TODAY THROUGH THURSDAY NIGHT/...Latest radar
imagery shows rain showers dissipating over the region, along
with the convergence zone in Snohomish County. Impressive QPF
amounts the last 24 hours over the western slopes of the
Olympics and North Cascades, with 2-3.5 inches of rainfall over
these areas. The previous discussion can be found below along
with updates to the aviation and marine sections:
Drier conditions develop Wednesday into Thursday as high
pressure begins to build into the Pacific Northwest. Morning
stratus and localized areas of fog due to residual moisture will
clear for some sunshine during the afternoon. A system will
weaken along the northern periphery of the ridge late Thursday,
resulting in a slight uptick in rainfall potential beginning
later Thursday into Thursday night, however any QPF amounts are
expected to remain light, mainly focused on areas near the BC
border. Highs mainly in the low to mid 60s Wednesday and
Thursday.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...The aforementioned
weakening system may continue to bring light rain along the
northern tier, mainly North Cascades on Friday, but
predominantly dry conditions are expected. Ensembles are in good
agreement in the upper ridge building further over the Western
US this weekend, with dry conditions and warming temperatures
over Western Washington. Dry conditions look to continue into
early next week, although an increase in onshore flow may result
in slightly cooler temperatures by Monday. JD
&&
.AVIATION...
Westerly flow aloft will continue into Wednesday with an upper ridge
axis centered well south of the region. Post-frontal low level
onshore flow will weaken overnight and become northerly on
Wednesday. Weak convergence persists over central Puget Sound this
evening producing a few showers and MVFR ceilings. Confidence in the
overall forecast ceilings areawide overnight is not high. However,
lighter surface winds and remnant low level moisture will favor the
development of IFR or low MVFR stratus. Stratus that does form will
lift and scatter toward midday on Wednesday with varying amounts of
mid and high level moisture streaming across the area.
KSEA...As referenced above, MVFR ceilings are likely to hang around
overnight and may drop to occasional IFR toward daybreak before
lifting and scattering out toward 19Z or 20Z on Wednesday. Surface
winds N/NE 6 to 9 knots easing overnight then becoming N/NW 7 to 10
knots Wednesday afternoon.
27
&&
.MARINE...
Surface high pressure building over the interior of British Columbia
and weak troughing just offshore will lead to the development of
some weak east/southeast flow on Thursday. Northerly or weak
offshore flow will develop across area waters later Friday into the
weekend as a thermally induced surface trough expands northward
along the coast.
27
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 2 AM PDT Wednesday 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