096
FXUS66 KSEW 100305
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
805 PM PDT Thu Jul 9 2026
.SYNOPSIS...
A weak front will bring increasing clouds and cooler temperatures
across Western Washington Friday into Saturday. Light rain chances
also exist, particularly for portions of the mountains. Upper
ridging will build back into the Pacific Northwest for warmer,
dry conditions Sunday through Tuesday. Onshore flow increases
again during the middle of next week.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
Mostly sunny skies across the area today with weak high pressure
aloft. Temperatures will peak in the 70s for the majority of
Puget Sound this afternoon, with cooler temperatures along the
coast with continued onshore flow.
A weak front will move across Western Washington Friday through
Saturday leading to increased onshore flow. Mostly cloudy conditions
are expected on Friday, with a bit more in the way of partial
sunshine late Saturday. In addition, light rain chances exist for
the Cascades and Olympics, as well as from King County northwards
Friday morning into Saturday. Rainfall amounts are expected to
be light (if any), primarily less than 0.10". Temperatures will
be a few degrees cooler both Friday and Saturday.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
A large scale upper level ridge will build across much of the
Interior Rockies and Central US early next week. Western Washington
will be located on the northwest periphery of this ridge. This
pattern will promote a warming trend, with dry conditions, Sunday
through at least Tuesday. Minor HeatRisk is expected during this
period, with a 10-35% chance of Moderate HeatRisk for Seattle metro
southwards to Olympia. Uncertainty grows in ensembles by Wednesday
with at least some indication of weak troughing developing offshore.
This would allow for an increase in onshore flow mid next week
with a slight cooling trend going into later next week. JD
&&
.AVIATION...
VFR conditions prevail across all TAF sites this evening with
west to northwesterly onshore flow continuing tonight. A stronger
marine push is expected to develop by Friday morning, with likely
MVFR/IFR ceilings as early as 05-09z spreading into the interior
through the morning hours. This layer looks to stick around through
the morning hours before dissipating around 20z-22z. NW winds this
afternoon 4 to 8 knots will return to a more S/SW direction by
early Friday morning.
KSEA...VFR conditions this evening will continue beyond sunset with
a return of stratus cloud cover by early Friday morning. Latest
guidance shows confidence in more widespread MVFR ceilings by 11z-
16z Friday as a marine layer spreads through the interior. Northwesterly
winds this evening of 4 to 8 knots will turn southerly and generally
remain the same speeds by early morning and continue through the day
Friday. VFR conditions return around 19-22z.
&&
.MARINE...
Surface high pressure remains over the coastal and offshore waters
this afternoon. High pressure will weaken into Friday as a weak
surface low shifts southward toward to just west of north Vancouver
Island. An associated weak frontal system will cross the waters
Friday afternoon into Friday night with little to no impact.
High pressure will rebuild Sunday into Monday. Diurnally driven
increases in westerlies can be expected in the Strait of Juan
de Fuca each the next several days.
Coastal seas remain 4 to 6 feet throughout much of the week.
Mazurkiewicz
&&
.FIRE WEATHER...
The current onshore pattern will continue through the weekend
which will lead to continued excellent nightly RH recoveries.
Light drizzle or rain chances exist Friday into Saturday, mainly
for the Olympics and Cascades. Rainfall amounts during this
period would total less than 0.10".
A ridge of high pressure briefly rebuilds into the region Monday
and Tuesday. While the onshore pattern will largely remain in
place, warmer daytime temperatures and clear skies will likely
lead to RH values dipping into the 20-40% percent range, with
the lowest values in the south interior and Cascades Valleys.
This will allow fine fuels to continue to dry with elevated fire
weather conditions.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 2 AM PDT Friday 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
Discussion Script by Ken True at Saratoga Weather - WFO Script by SE Lincoln Weather
