930
FXUS66 KSEW 100350
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
850 PM PDT Tue Jun 9 2026
.SYNOPSIS...Showers will taper off outside of convergence zone
showers and thunderstorms today, with drier and warmer
conditions settling into the region through the weekend and into
early next week. Areas of Moderate (Orange) HeatRisk will
expand across the lowlands by Sunday and continue into Monday
with pockets of Major (Red) HeatRisk possible.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...A frontal system
moved across the region earlier today, leaving widespread
breezy winds and light shower activity in its wake. A Puget
Sound Convergence Zone is well underway this afternoon over
Snohomish County, and has produced a few lightning strikes so
far in heavier shower activity. While most other areas dry out,
convergence zone activity is expected to persist overnight and
will likely be stalled over Snohomish County due to breezy
southwesterly winds.
Wednesday will kick off a warming and drying trend across
western Washington as weak high pressure passes over the region
and a high pressure ridge begins to build offshore. Wednesday
morning will likely feature another round of marine stratus
creeping inland, with sunny skies prevailing by the afternoon.
The region will see some warming, though temperatures will still
peak a few degrees below normal on Wednesday in the mid to upper
60s across the lowlands.
Northwesterly flow aloft will prevail on Thursday as the upper
level ridge offshore to the south slowly amplifies northward.
Despite a cool and cloudy morning, Thursday will bring
additional warming with sunny skies in the afternoon. Highs will
peak in the upper 60s to lower 70s. This will introduce
widespread Minor (Yellow) HeatRisk across much of the lowlands.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...A warming and drying
trend will continue into the weekend as an upper level ridge
continues to build offshore. A thermal trough moving up the
coastline will reach western Washington by late Saturday, with
easterly offshore flow developing as a result on Sunday and
Monday. Temperatures Sunday are on track to peak in the upper
80s to lower 90s, with even warmer conditions south and east of
the Puget Sound Monday with temperatures peaking in the low to
mid 90s. This will introduce widespread Moderate (Orange)
HeatRisk both days, with up to a 30% to 50% chance for Major
(Red) HeatRisk near the metro areas on Monday. A few locations
may even break daily temperature records on Sunday and Monday.
Longer range models suggest a pattern change may be on track for
the middle of next week, bringing an end to the incoming heat
wave.
15
&&
.AVIATION...A post-frontal convergence zone continues in
Snohomish County this evening, wit a 20% chance of thunder
remaining with this activity throughout the evening. Conditions
with this convergence zone have dropped locally to MVFR/IFR at
times, with cloud tops less than 20,000 ft. Showers in the
southwest interior/coast have also resulted in brief drops to
MVFR as they pass over the terminal. The shower activity will
continue into early Wednesday morning. Breezy southwest winds
also continue this afternoon, with sustained winds up to 20 kt
and gusts up to 30 kt. Winds will taper down tonight into
Wednesday to around 4-8 kt, with only the Strait of Juan de Fuca
area remaining breezy part way into Wednesday. A few Puget
Sound locations will see winds turn to the north late Wednesday
afternoon (via diffluence from the strait). There remains a
40-60% of widespread MVFR ceilings redeveloping tonight and into
Wednesday morning through 18-21Z (with the highest chance for
LIFR/IFR conditions remain in the mountains).
KSEA...VFR through tonight, with convergence zone activity remaining
north of the terminal. Will remain breezy through tonight with
sustained winds 15-20 kt with gusts up to 30 kt diminishing to
around 4-8 kt by Wednesday morning. Potential for north winds at
around 5 kt or less after 00Z Thursday. MVFR probabilities
increase to 40-60% around 10Z through 20Z, before scattering
out.
HPR/Mazurkiewicz
&&
.MARINE...A strong onshore push in wake of a front that went
through late last night/this morning continues. Showers will
continue across a majority of the waters through the
evening/Wednesday morning. The only threat for thunder remains
in the north Puget Sound/water areas adjacent to Whidbey Island
with a convergence zone continuing into the evening. Winds
remain breezy across the interior waters, with Strait of Juan de
Fuca winds continuing to remain the breeziest with gale gusts
through this evening into tonight. Breezy southwest winds also
continue in the Puget Sound, Admiralty Inlet, and Northern
Inland Waters through tonight. Diurnal pushes through the Strait
of Juan de Fuca will continue through the week, although
probability has decreased with the potential for small craft
winds. A thermal trough building along the coast this
weekend/early next week may result in periods of offshore flow.
Seas at 6-8 ft today into Wednesday will decrease to 4-6 ft Thursday
through the weekend/next week, with a brief increase to 6-8 ft seas
Friday.
HPR
&&
.FIRE WEATHER...After some wetting rains, western Washington
will see a warming and drying trend settle into the region
through early next week. A thermal trough will develop offshore
by late Saturday, causing winds to shift easterly offshore. This
will allow fine fuels to cure, with RH dropping to near
critical levels over the weekend. Larger fuels may also see
drying with this heat wave. Fire weather concerns will remain
elevated into the weekend and will peak on Monday, corresponding
with the warmest expected day of the heat wave. The thermal
trough will shift inland on Monday before potentially shifting
eastward by Tuesday and allowing the region to see cooler
temperatures.
15
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Gale Warning until 5 AM PDT Wednesday for Central U.S. Waters
Strait Of Juan De Fuca-East Entrance U.S. Waters Strait
Of Juan De Fuca.
Small Craft Advisory until 11 PM PDT this evening for
Admiralty Inlet-Northern Inland Waters Including The San
Juan Islands.
Small Craft Advisory until 10 PM PDT this evening for Puget
Sound and Hood Canal.
&&
$$
NWS SEW Office Area Forecast Discussion
Discussion Script by Ken True at Saratoga Weather - WFO Script by SE Lincoln Weather
