623
FXUS66 KSEW 082122
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
222 PM PDT Wed May 8 2024

.SYNOPSIS...A high pressure ridge will continue to build inland
from the Pacific Coast through the first half of the weekend,
allowing for a warming trend paired with dry conditions. Friday
and Saturday will be the hottest days of the year so far. A weak
system passing to the north of the area on Sunday will bring a
cooling trend towards the end of the weekend and into early next
week.

* HEAT: Temperatures are on track to surpass 80 degrees for much
  of the lowlands on Friday and Saturday. Overnight low
  temperatures will also stay elevated in the 50s, providing
  little relief for the heat.

* COLD WATER: Despite warm air temperatures, waterways across the
  region are still cold. Use caution if recreating around water.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY/...High pressure will
continue to build inland across western Washington today,
allowing conditions to dry out and warm up. Clearing skies will
allow temperatures to return to normal, with many locations
already in the 60s as of 2 PM PDT. Warming will continue into
Thursday as the ridge overhead continues to amplify, with most
areas reaching the mid to upper 70s. As low level flow turns
offshore, areas along the coast and south of the Olympics will
have the best shot at seeing the first 80 degree day of the year
on Thursday. Overnight lows heading into Friday morning will jump
up several degrees across the region, with most areas bottoming
out in the low to mid 50s.

Friday and Saturday will trend even warmer as high pressure aloft
continues to dominate the weather pattern. Western Washington will
see temperatures roughly 15 to 20 degrees above normal heading
into the weekend, with most areas below 1000 ft reaching the 80s
by Friday. The coast will see the warmest conditions on Friday
under the influence of a thermal trough, and a switch to onshore
flow on Saturday will cool the coastal areas roughly 10 to 15
degrees. The thermal trough will drift inland and allow areas
mainly east of the Puget Sound to see the warmest conditions on
Saturday. While the daily temperature records at SeaTac for
Friday and Saturday are both set at 87 degrees (set in 2020 and
1971), reaching these records is not out of the realm of
possibility. Current ensembles show a probability of 20 to 30
percent, slightly higher on Saturday as the warmer air mass nudges
inland.

Daytime temperatures will be the hottest of the year so far, and
so will overnight lows in the mid 50s. SeaTac is on track to reach
the daily record for warmest overnight low on Saturday morning,
set at 55 degrees in 1988. Areas along the coast, including
Quillayute, are also on track to see abnormally warm overnight
lows heading into Saturday as the thermal trough shifts eastward.
This will provide little relief to the weekend heat, which may
pose a risk to individuals particularly sensitive to heat,
especially outdoors without effective cooling or hydration.

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...Temperatures will fall
several degrees on Sunday as flow shifts onshore. Models continue
to show a weak trough skirting us to the north, though this will
be enough to moderate temperatures and cause the ridge to flatten.
Ensembles remain in good agreement over the potential for drier
and warmer conditions to continue into mid-week next week, aside
from a slight chance of light shower activity over higher terrain
along the periphery of the ridge.

Lindeman

&&

.AVIATION...Northerly flow aloft will transition more northeasterly
into Thursday as ridging builds into the area. VFR cigs this
afternoon with areas of SCT mid clouds across the southern Olympic
Peninsula and Puget Sound. A drier airmass will result in continued
mostly clear conditions for most areas into Thursday. Patchy fog or
low cigs in river valleys Thursday morning, mainly near the
Snohomish and Chehalis River basins. Northerly winds will become a
bit lighter tonight before increasing again midday Thursday.

KSEA...VFR cigs with FEW/SCT mid clouds this afternoon. Mostly clear
skies expected into Thursday. Northerly winds this afternoon will
lighten a bit and transition more NE tonight. JD

&&

.MARINE...High pressure will continue to build over the waters into
tonight with a thermal trough moving up the coast and advancing
inland later Friday into Saturday. Northerly winds will remain a bit
more elevated for the Coastal Waters into this evening with periods
of SCA winds for the central and southern inner Coastal Waters. In
addition, brief west wind gusts will occur into this evening for the
central Strait of Juan de Fuca. Winds will generally remain more
northerly into the weekend before transitioning more onshore early
next week.

Seas of 5 to 8 feet through late week. JD

&&

.HYDROLOGY...The daily hydrology discussion has ended until the
start of the next rainy season; it will only be updated as needed.
&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 8 PM PDT this evening for Central
     U.S. Waters Strait Of Juan De Fuca.

     Small Craft Advisory until 11 PM PDT this evening for Coastal
     Waters From James Island To Point Grenville Out 10 Nm-
     Coastal Waters From Point Grenville To Cape Shoalwater Out
     10 Nm.

&&

$$