541
FXUS66 KSEW 092229
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
329 PM PDT Sun Jun 9 2024

.SYNOPSIS...Brief upper-ridging will rebound on Monday but only
to be replaced by weak troughing and shower activity on Tuesday.
Mostly zonal flow aloft afterwards with near-normal temperatures
however, cooler and wetter weather looks to return by the weekend.

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...As mentioned, a
transient ridge looks to build into the region tonight as upper-
troughing shifts into the Inland Northwest. Mostly dry conditions
are expected but onshore flow looks to strengthen. With that,
widespread marine stratus is expected to develop across W WA
overnight into early Monday. Low temperatures are to range mid 40s
to lower 50s around seasonal after a day of above average
temperatures.

Dry conditions are favorable for Monday with weak ridging in the
500 mb levels but upper-troughing will return Monday night into
Tuesday along with shower chances. Areas with the best chance for
wet weather are favored mostly along the coast, northern interior
and higher elevations. Temperatures are expected to cool also, as
forecast highs on Monday of low to mid 70s across the interior
will fall to the mid to upper 60s on Tuesday. Low temperatures
are to be in the mid 40s to lower 50s for both nights.

We`ll see zonal flow aloft on Wednesday throughout the region.
Any lingering showers are expected to dry out but marine stratus
will remain during the morning before burning off by the
afternoon. Pleasant conditions are in the offing with seasonal
temperatures.


.LONG TERM /THURSDAY THROUGH SUNDAY/...Guidance is keying in on
weak ridging returning on Thursday with a slight bump up in
temperatures. But, a trough will swing out of the Gulf of Alaska
and into the region on Friday and influence conditions into the
weekend. Here we`ll see another period of below-normal
temperatures and chances for showers across the region.

McMillian


&&

.AVIATION...A weak upper level trough will continue to exit the
region, moving into eastern Washington tonight. Zonal flow will
then persist tonight into Monday. Radar showing a few light
showers over the northern portions of the Cascades this afternoon,
but overall thunder threat looks to remain mostly east of the
Cascade crest. Satellite still showing stratus retreating, but
persisting along the coast this afternoon. Conditions for the
majority of the interior terminals have rebounded to VFR, however
MVFR ceilings remain for terminals in stratus. Increasing low
level onshore flow tonight will yield another round of stratus
pushing into the interior by early Monday morning (most likely
between 09-12Z for interior terminals). Extent of stratus looks
to be more widespread than this morning and will likely result in a
few hours of MVFR to IFR conditions. A rebound to VFR for majority
of terminals likely by 18Z as stratus scatters.

KSEA...VFR today with S/SW winds 5-10kt. Low clouds and MVFR
conditions, along with light/variable wind, overnight toward
12Z Mon.

14

&&

.MARINE...High pressure will remain situated over the northeastern
Pacific through Monday for periods of northerly winds over the
coast and westerlies through the Strait of Juan de Fuca. Another
strong push of westerlies is expected down the strait tonight-
where a Gale Warning remains in effect. Meanwhile, have issued a
small craft advisory through this evening for seas across the
coastal waters hovering around 10 ft. Seas will gradually continue
to subside tonight and back towards 4-6 ft again on Monday. A
frontal system will then move across the area waters on Tuesday.
Seas look to increase back towards 10-12 ft over the coastal
waters on Tuesday. High pressure will then build back into the
region in the wake of the front Tuesday night into Wednesday.
Another front looks to traverse the area waters late in the week.

14

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 8 PM PDT this evening 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-Grays Harbor Bar.

     Gale Warning until 5 AM PDT Monday for Central U.S. Waters
     Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of
     Juan De Fuca.

&&

$$