485
FXUS66 KSEW 180339
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
839 PM PDT Mon Jun 17 2024

.UPDATE...A few lingering showers this evening, particularly in an
area of weak convergence over King/Snohomish Counties. Showers
will slowly taper off tonight for generally dry conditions
Tuesday. Morning clouds will clear for some afternoon sunshine on
Tuesday. No major forecast updates this evening.

&&

.SYNOPSIS...High pressure aloft will gradually build through the
week, allowing conditions to dry out and warm up. A pattern change
is on track for the end of the week as a trough brings wetter and
cooler conditions to western Washington.

&&

.SHORT TERM /TONIGHT THROUGH FRIDAY/...Cool weather continues
over western WA as an upper level trough lingers over the Pac NW.
There are a few showers too, mainly over the central and southern
sound and Cascades. Showers will gradually fade tonight as the low
shifts farther east. Look for temps in the upper 40s to lower 50s
overnight.

The air mass will be drier and warmer moving forward as high
pressure starts to move in. Temperatures will be close to average
on Tuesday, then above normal and in the 70s and lower 80s on
Wednesday and Thursday. The coast will be cooler and in the 60s
with NW winds. A few showers may develop over the North Cascades
on Wednesday, otherwise dry weather is expected for the lowlands.
33

.LONG TERM /SATURDAY THROUGH TUESDAY/...Temperatures spike on Friday
as the upper level ridge builds over the region. Highs in the
interior will reach the low to mid 80s and close to the warmest
temperatures of the season so far (although not record breaking).
There is a pocket on Moderate Heat Risk in the interior but we
should see some relief at night with overnight lows in the 50s.

Heights dip on Saturday the the ridge exits east and we`re back in
S/SW flow. We`re still above normal but temperatures will mostly
track in the 70s. Onshore flow will continue to bring cooler 60s
to the coast. Sunday through Monday we`re back to 60s (or slightly
cooler than average) as an upper level trough moves in. Stronger
onshore flow will bring in more clouds and we`ll also see a few
showers as well. 33

&&

.AVIATION...Northerly flow aloft continues as broad upper level
troughing departs to the east. A few lingering light showers remain
across western Washington, mostly confined to the Cascades in the
form of a convergence zone and foothills as well as the Pacific
coast. Ceilings mostly VFR across the region with a few pockets of
MVFR cigs remaining. Ceilings should remain largely VFR through this
evening. However, MVFR ceilings may stick around KPAE. Widespread
MVFR development is expected after 12Z Tuesday, remaining through
the early morning hours. Cloud cover should dissipate throughout the
day tomorrow, giving way to VFR conditions.

South/southwesterly winds continue through this evening, decreasing
to light and variable overnight. Winds look to switch to
northwesterly tomorrow.

KSEA...VFR conditions continue through this evening. Light showers
continue to the east, through a weak convergence zone north of the
terminal may keep ceilings locally lower into the evening.
Widespread MVFR conditions return after 12Z Tuesday through around
18Z Tuesday. Southwesterly winds decrease tonight becoming light,
then a wind shift to northwesterly is expected after around 21Z
tomorrow.

LH/McMillian

&&

.MARINE...Broad high pressure is centered just offshore in the NE
Pacific, which will dominate the pattern into the weekend. A push of
westerlies through the Strait of Juan de Fuca has started and will
remain into early Tuesday morning, for which a Small Craft Advisory
is in effect. The Strait will see several additional weak pushes,
but none look to be as strong as tonight`s. A frontal system will
approach the waters for the weekend, bringing rain showers, but
winds do not appear to be of concern at this time. Additional pushes
down the Strait beginning Sunday may require additional headlines.

Seas remain 4 to 6 ft through the remainder of this week, rising to
6 to 8 ft beginning this weekend.

LH/McMillian

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 2 AM PDT Tuesday for Central U.S.
     Waters Strait Of Juan De Fuca-East Entrance U.S. Waters
     Strait Of Juan De Fuca.

&&

$$