491
FXUS66 KSEW 042137
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
237 PM PDT Tue Jun 4 2024

.SYNOPSIS...Widespread precipitation and breezy conditions will
continue to diminish through tonight. A pattern change will result
in high pressure building over the region through late this week,
allowing temperatures to rise to above normal levels. The warmest
temperatures will likely occur Friday and Saturday across western
Washington before falling back towards normal by early next week.

&&

.SHORT TERM /TONIGHT THROUGH FRIDAY/...Precipitation over the
last 12 hours has been on the light side of the probabilistic
guidance. Generally less than an inch has fallen across the
Cascades and while river levels have bumped up slightly, no
flooding is expected. Winds have also peaked across the region and
will continue to gradually decrease through the afternoon and
evening. We will also continue to monitor a weak signal for
thunderstorms, but impacts will likely remain minor.

Synoptic ridging will begin to develop across the PNW Wednesday
and is likely to peak in amplitude Friday. This will result in a
fairly rapid warm up through the end of the workweek with
temperatures reaching the upper 70s and low 80s. HeatRisk levels
will peak Friday, with widespread minor/yellow HeatRisk and
isolated moderate/orange HeatRisk - mainly in favored areas such
as the Cascade Foothills and urban heat island areas such as the
Auburn/Kent valley.

.LONG TERM /SATURDAY THROUGH TUESDAY/...Warm temperatures will
continue into Saturday with highs away from the coast near to
slightly above levels seen Friday (the coast will be several
degrees cooler). However, with cooling expected Saturday night,
24-hour HeatRisk will fall back solidly into the yellow/minor
category. This cooling will arrive as the ridge axis moves east of
the area allowing onshore flow to increase across western WA.

Sunday through early next week ensembles favor a trough over the
eastern Pacific with occasional shortwaves ejecting across the
PNW. This will likely keep temperatures near to slightly above
normal as well as occasional cloud cover and chances for mainly
mountain showers.
-Wolcott-

&&

.AVIATION...Flow aloft still strong and westerly with the jet max
coming ashore into Washington/B.C. Canada with an upper level
trough/frontal system passing through today. Satellite shows quite
a bit of cloud cover yet to clear out (but a few clearing areas
are visible near the Kitsap Peninsula). A few showers will
continue across all of Puget Sound this afternoon (some of the
showers may be convective, although the risk of a thunderstorm is
low). MVFR ceilings/visibilities (with pockets of IFR at times
with the heaviest showers and at KPAE) will improve to low-end VFR
later this evening as the frontal system moves out. Low ceilings
are possible Wednesday morning. Winds continue to gust to 25 kt
out of the south-southwest, and will decrease overnight and become
westerly (will become northwesterly late Wednesday afternoon).

KSEA...Few showers continuing, may drip CIGs/VIS down to IFR at
times. Otherwise MVFR will improve to VFR late Tuesday evening.
Slight chance of low CIGs morning but is expected to be VFR/MVFR
at this time (no fog expected). Winds still gusty this afternoon
out of the southwest up to 25 kt. Will diminish to around 5 to 10
kt overnight, become westerly and eventually northwesterly late
Wednesday afternoon.

HPR

&&

.MARINE...A frontal system continues to bring showers across the
inner waterways this afternoon. A few of these may become
convective, potentially reducing visibilities to mariners (as well
as producing gusty winds). Gusty winds are expected to diminish
from 00Z-06Z across all waterways. Onshore flow will pick up as
high pressure builds off the coast (with low pressure inland).
Seas will begin to build to hazardous levels for the coastal
waters, Grays Harbor Bar, and western Strait of Juan de Fuca
through early Thursday morning (waves of 9 to 15 ft - steepest
waves in the outer coast). Otherwise light winds out of the
northwest for the remainder of the week, and seas will return to 4
to 6 ft Thursday through Saturday, building to 6 to 8 ft Sunday
with another system.

HPR

&&

.HYDROLOGY...Rain rates with the ongoing system have remained
below concerning thresholds. The Flood Watch was cancelled this
morning. Rivers will continue to run cool and fast this week
despite warm and dry conditions late this week into the weekend.
-Wolcott-

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 5 AM PDT Thursday for Coastal Waters
     From Cape Flattery To James Island 10 To 60 Nm-Coastal
     Waters From Cape Flattery To James Island Out 10 Nm-Coastal
     Waters From James Island To Point Grenville 10 To 60 Nm-
     Coastal Waters From James Island To Point Grenville Out 10
     Nm-Coastal Waters From Point Grenville To Cape Shoalwater
     10 To 60 Nm-Coastal Waters From Point Grenville To Cape
     Shoalwater Out 10 Nm-West Entrance U.S. Waters Strait Of
     Juan De Fuca.

     Small Craft Advisory until 11 PM PDT this evening for Central
     U.S. Waters Strait Of Juan De Fuca.

     Gale Warning until 5 PM PDT this afternoon for Admiralty Inlet-
     East Entrance U.S. Waters Strait Of Juan De Fuca-Northern
     Inland Waters Including The San Juan Islands.

     Small Craft Advisory from 5 PM this afternoon to 11 PM PDT this
     evening for East Entrance U.S. Waters Strait Of Juan De
     Fuca.

     Small Craft Advisory until 5 PM PDT this afternoon for Puget
     Sound and Hood Canal.

&&

$$