FXUS66 KSEW 242131
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
231 PM PDT Wed Jul 24 2024

.SYNOPSIS...Upper level trough over Western Washington through
Thursday with a chance of showers north part. A weaker trough
will take its place over the weekend into the first part of next
week. Temperatures will be close to normal.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY/...An upper level low and
onshore flow will give western WA generally mild weather over the
next few days. Temperatures are in the 60s (coast) and 70s
interior or close to late July normals. We will see a few showers
as the trough moves overhead tonight and Thursday, with showers
mainly over the coast and mountains. The North Cascades have the
best shot at seeing wetting rains. Thursday will be a few notches
cooler although still seasonably mild.

A weak trough will remain over western WA Friday and Saturday as
the upper low shifts NE toward northern Alberta/Saskatchewan.
Temperatures will continue to track close to normal through the
period.

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...Troughing remains over the
region on Sunday for a repeat of mild, late July weather. We may
tap into some moisture over the Pacific early next week (Mon-
Tuesday night) for a chance of showers. There's a 70% chance of
seeing measurable precipitation through the period in the
lowlands. The mountains have a 60-70% chance of seeing wetting
rains (0.25" or more). Temperatures nudge upwards Wednesday
afternoon with broad ridging over the Rockies. Around half of the
ensemble runs have interior lowland temperatures in the lower 80s
again. 33

&&

.AVIATION...West/southwest flow aloft with a large upper level
trough over the region. In the low levels, southwesterly winds will
transition to becoming northwesterly tonight as onshore flow
increases behind a weak front currently moving through the area.
Winds persist overnight, returning beck to southwesterly early
tomorrow morning. Winds remain southwesterly tomorrow but gradually
turning back to northerly tomorrow evening.

Most locations are VFR this afternoon with a scattered mid-level
cloud deck, with MVFR conditions on the coast associated with what
is left of the front. Expecting increasing cloud cover tonight
across the region. Increasing convergence overnight may allow for
MVFR ceilings over Snohomish and Skagit counties. Low-end VFR
ceilings are expected elsewhere. Skies will clear out and lift
throughout the day tomorrow, with a return to VFR conditions
everywhere tomorrow.

KSEA...Mostly clear skies with increasing mid and high level clouds
this afternoon. Ceilings developing and lowering overnight, through
expected to remain above MVFR. VFR conditions return Thursday
morning with gradual clearing.

West/southwest winds turning northerly this evening before returning
to southwesterly overnight. Winds will again gradually turn from
southwesterly to northwesterly over the course of tomorrow, with
speeds generally remaining in the 5 to 10 kt range.

LH

&&

.MARINE...Surface high pressure will remain offshore over the
eastern Pacific Ocean with low pressure inland, maintaining
northwesterly onshore flow. A weak front currently over the coastal
waters is rapidly dissipating as it moves onshore. The next frontal
system may approach the region by the beginning of next week.

Winds will continue to increase tonight through the Strait of Juan
de Fuca. Widespread gusts to gale force, with sustained winds near
or just below gale force. The Gale Warning remains in effect for the
Central and Eastern Strait of Juan de Fuca, with a Small Craft
Advisory as well for Admiralty Inlet.

Additional westerly pushes down the Strait will continue through
this weekend and into next week. Some may require additional
headlines but none look to be as strong as tonight at this time.

Seas remain 3 to 6 ft into next week.

LH

&&

.FIRE WEATHER...We're continuing to see benign fire weather
conditions for the next several days. Stout onshore flow off the
Pacific will keep concerns to a minimum. Isolated pockets of
critical RH values are possible in the Cascade zones of 658 and 659
but, decent overnight recoveries are expected. 20-40% chance of
showers overnight Wednesday into Thursday morning for the Northern
Interior with little to no chance of wetting rain. The next threat
for precipitation is favored to arrive Monday-Tuesday of next week
with a better chance of wetting rain as widespread precipitation
looks to be at play in what's climatologically the driest time of
the year.

McMillian

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Gale Warning until 5 AM PDT Thursday for Central U.S. Waters
     Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of
     Juan De Fuca.

     Small Craft Advisory from 6 PM this evening to 5 AM PDT Thursday
     for Admiralty Inlet.

&&

$$