103
FXUS66 KSEW 110312
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
812 PM PDT Mon Jun 10 2024

.SYNOPSIS...A weak shortwave trough will enter on Tuesday with
light precipitation and slightly below average temperatures.
Mostly zonal flow to weak ridging into remainder of week with
benign conditions. But, cooler and wetter weather is slated to
return around the week`s end.

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY/...No significant changes
were made to the forecast this evening. The previous discussion
can be found below along with updated aviation and marine
sections:

A transient weak upper- level ridge is currently over the region.
Model guidance has its axis crossing the Cascades and into the
Inland Northwest later tonight. This progression will clear the
way for a shortwave trough ejecting out of an upper-low positioned
over the Gulf of Alaska into the area. Overnight lows are
forecast to fall into the upper 40s to mid 50s.

A weak front associated with the aforementioned shortwave will
enter into the early morning hours on Tuesday bringing light rain
and showers along the coast. Precipitation is expected to
continue inland as the morning progress with meager amounts. Up to
0.10-0.25" of rainfall is forecast along the coast and windward
Olympics. Similar is expected through the northern and central
Cascades but less than 0.10" is most probable throughout the
lowland interior. High temperatures will rise to the mid to upper
60s for most areas with mid 50s to lower 60s along the coast.
Widespread 40s are in the cards for lows.

The rest of the short term will feature pleasant conditions
across W WA. Guidance agrees on zonal flow aloft on Wednesday
before transitioning to weak upper-level ridging on Thursday.
Near-normal temperatures are in the offing with highs in the mid
60s to lower 70s on Wednesday then rising to the lower to mid 70s
for the interior. This won`t be long lasting however as the
pattern becomes active again towards the week`s end.

.LONG TERM /FRIDAY THROUGH MONDAY/...Juneary looks to return right
on time for the weekend. An upper-low out of the Gulf of Alaska
will bring increased rain and shower chances along with much
cooler weather. By Saturday, temperatures could range anywhere
from 5-10 degrees below normal for mid-June. Precipitation amounts
continue to look generally light through this period.

McMillian

&&

.AVIATION...Increasing west-southwest flow aloft across the area
with a weakening front into Tuesday. Widespread VFR conditions this
evening with a few lingering mid clouds and gradually increasing
high clouds. Cigs will lower along the coast tonight into Tuesday
morning with generally MVFR conditions expected. Additionally, there
is the potential for IFR conditions to emerge at PWT overnight and
early Tuesday morning. Interior cigs will lower Tuesday morning with
increasing light rain potential as a weakening front moves across
the area, likely reaching MVFR for portions of Puget Sound in the
morning. A convergence zone Tuesday afternoon across Snohomish
County and drifting southwards into Tuesday night may result in
locally lower cigs. Light W/NW winds into this evening with
increasing southerly winds tonight with the front.

KSEA...VFR with periods of high clouds into tonight. Cigs will lower
Tuesday morning as a weakening front moves through the area. A brief
period of MVFR is possible, mainly between 15-19z. Some clearing
expected in the afternoon with convergence zone drifting southward
late afternoon and evening. Light NW winds into this evening with
increasing S/SW winds Tuesday morning. Winds will then shift
northerly later Tuesday afternoon, generally ranging 8 to 14 kts
during the period. JD/18

&&

.MARINE...Lighter winds into this evening with increasing southerly
winds, especially for the Coastal Waters, later tonight into Tuesday
morning as a weakening front moves across the area. A period of
westerly SCA wind gusts will be possible Tuesday for the outer
Coastal Waters. Westerly winds will then increase Tuesday afternoon
into Tuesday night for the Strait of Juan de Fuca with SCA winds
likely. Winds will become more northerly Wednesday into Thursday
with more of an onshore flow pattern Friday into the weekend.

Seas of 4 to 6 feet into this evening will build to 9 to 14 feet
Tuesday into Tuesday night, which will likely warrant wave-based SCA
headlines. Seas will slowly subside below 10 feet on Wednesday.
JD/18

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory from 11 AM Tuesday to 5 AM PDT Wednesday
     for Coastal Waters From Cape Flattery To James Island Out
     10 Nm-Coastal Waters From James Island To Point Grenville
     Out 10 Nm-Coastal Waters From Point Grenville To Cape
     Shoalwater Out 10 Nm.

     Small Craft Advisory from 8 AM Tuesday to 8 AM PDT Wednesday for
     Coastal Waters From Cape Flattery To James Island 10 To 60
     Nm-Coastal Waters From James Island To Point Grenville 10
     To 60 Nm-Coastal Waters From Point Grenville To Cape
     Shoalwater 10 To 60 Nm.

&&

$$