124
FXUS66 KSEW 080325
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
825 PM PDT Sun Jul 7 2024

.UPDATE...Temperatures remain very warm this evening, with temps
generally 2-6 degrees warmer than 24 hours ago. This will set up a
warm night, particularly across interior areas away from the
water. Lows will likely range in the upper 50s to mid 60s for
most, with little relief to the heat overnight. Otherwise, hot
conditions again on Monday. No major forecast updates to this
forecast.

&&

.SYNOPSIS...Hot and dry conditions will persist under a strong
upper level ridge through the first half of the week. Some relief
is expected around midweek as the ridge moves eastward and weakens.
However, above normal temperatures and no precipitation will
remain.

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY/...Yet another day of very
hot temperatures is well underway across Western Washington. At
this hour, many locations have climbed into the 80s along the
coast and a mix of 80s and lower 90s through the region. We may
again see a few record high temperatures for the date fall, with
Hoquiam already toppled today. Not much in the way of significant
changes in store with high pressure over the region and the
thermal low pressure building up over the region into Monday
before pushing eastward Tuesday. This will maintain very hot
temperatures through the early part of next week, with areas of
Moderate (orange) to Major (red) HeatRisk expected through the
interior portions of western Washington. Overnight lows will also
remain in the lower 60s for areas inland, making for slow relief
from the very hot daytime highs.

Still expect Monday and Tuesday to be the warmest days of the
week for most with the upper ridge axis moving eastward over the
region. This will bring some light onshore influence back to the
immediate coast into the afternoon, but little help for the
interior with the thermal low pressure building overhead and
cutting off much in the way of surface wind. Additionally, expect
very warm nights in the mountains as the subsidence inversion
strengthens. Have extended the heat advisory for the coast through
Tuesday morning. While temperatures along the immediate coast will
begin to moderate and see more significant overnight relief, there
remains some question of how far inland the marine influence will
be able to push. As a result, extended this to cover through the
Monday night period after one more fairly warm day away from the
coastline. Tuesday will be notably cooler for the coastal areas
and into the Olympics as onshore flow begins to return. Areas as
far as Chehalis, Olympia, and Shelton may see some moderation by
Wednesday morning. This will be quite slow to push further into
the interior with Wednesday remaining quite warm through the Puget
Sound region (especially after another very warm night). This may
require some extension of the heat advisory for areas from
Seattle and east into the Cascade valleys.

One other note with the stronger onshore flow as it arrives late
Wednesday: forecast guidance has trended notably stronger with
some gusty winds as the trough pushes east. This will be most
notable along the coastal areas, but will need to monitor the
potential for gusty winds ahead of the more humid air, especially
as it relates to fire weather concerns.

.LONG TERM /FRIDAY THROUGH MONDAY/...Still some minor
differences emerging in the timing of the ridge weakening as a
weak shortwave moves across the region, but ensemble guidance
remains in fairly strong agreement that it will be enough to
shift the pattern back down from the extremely hot and dry pattern
to one that is probably better described as fairly warm.
Increasing onshore flow should bring a return of higher daytime
humidities with good overnight recoveries, and high temperatures
that are only climbing into the 80s. While this is some 10-ish
degrees cooler than where we`ll be in the preceding days, this
will be a continuation of above normal temperatures through the
second half of the week with still no significant prospects for
precipitation in sight for the local area. Cullen

&&

.AVIATION...Northwesterly flow aloft continues as high pressure
amplifies over the west. VFR conditions throughout the TAF period,
except at KHQM where IFR/LIFR conditions are expected late tonight
through sunrise tomorrow as a weak marine stratus push develops
around 06-09Z. N/NE winds continue tonight at around 4 to 8 kt,
increasing to 8 to 12 kt tomorrow.

KSEA...VFR conditions throughout the TAF period. N/NE 4 to 8 knots
tonight, increasing to 8 to 12 kt by tomorrow afternoon.

LH

&&

.MARINE...High pressure remains situated offshore, with a thermal
trough along the west coast and north/northwesterly winds over the
coastal waters. Generally benign marine conditions will persist
through the first half of the week.

A surface front looks to sweep over the coastal waters Wednesday
night into Thursday for increased onshore flow and for stronger
pushes down the Strait of Juan De Fuca. Winds look to become
elevated over the coastal waters and through the Strait through
the end of the week.

Coastal seas 4 to 6 feet through the first half of the week,
gradually increasing to 6 to 8 feet by the end of the week.

Maz

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Heat Advisory until 10 PM PDT Tuesday for Admiralty Inlet Area-
     Bellevue and Vicinity-Bremerton and Vicinity-East Puget
     Sound Lowlands-Eastern Strait of Juan de Fuca-Everett and
     Vicinity-Hood Canal Area-Lower Chehalis Valley Area-
     Olympics-San Juan County-Seattle and Vicinity-Southwest
     Interior-Tacoma Area-West Slopes North Cascades and Passes-
     West Slopes North Central Cascades and Passes-West Slopes
     South Central Cascades and Passes-Western Skagit County-
     Western Whatcom County.

     Heat Advisory until 11 AM PDT Tuesday for Central Coast-North
     Coast-Western Strait of Juan De Fuca.

     Red Flag Warning until 11 PM PDT Tuesday for West Slopes of the
     Central Cascades Generally above 1500 Feet-West Slopes of
     the North Cascades Generally above 1500 Feet.

PZ...None.
&&

$$