781
FXUS66 KSEW 100329
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
829 PM PDT Tue Jul 9 2024

.SYNOPSIS...Very hot and dry conditions continue today across the
region as the upper level ridge remains over the area. Thermal low
pressure will shift eastward today, bringing increased onshore
low level winds to the coast by tonight. This brings some cooler
temperatures for many over the next two days, but still well above
normal. High pressure remains over the region with high temperatures
remaining above normal through early next week.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY/...Temperatures across
western Washington as of 8 PM are still in the lower to mid 90s,
through cooler in the 70s to 80s near the water, down to the mid
60s along the Pacific Coast as onshore flow increases tonight.
With the upper level ridge axis as well as the thermal low
pressure shifting eastward tonight into tomorrow, onshore flow
will slowly increase. This will be enough to bring some cooling
to areas closer to the coast as the marine layer develop and
pushes inland overnight into early tomorrow morning, but this
will not be a deep enough push into the interior. As a result,
still expect one more fairly warm day tomorrow with temperatures
around Seattle again climbing to around 90 degrees for one last
day. Similarly places in the Cascade valleys and foothills will
again be quite warm before a stronger marine push Wednesday night
into Thursday. This will result in the coolest day of the week
Thursday, but this is relative as afternoon highs likely still
climb into the mid 80s inland (or about 7-10 degrees above
normal). Heights rise a bit into Friday with temperatures again
climbing toward the upper 80s and a return of moderate (Orange)
HeatRisk that will continue into the weekend.

Cullen/LH

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...Warm temperatures are
favored to continue this weekend through early next week as
western Washington remains on the periphery of a strong ridge
drifting eastward over the southern US. While light onshore flow
will keep the coast in the low 70s, areas inland will see highs in
the mid to upper 80s, corresponding to moderate HeatRisk. Ensembles
remain in good agreement that no precipitation is likely through
the next week or beyond.

Cullen

&&

.AVIATION...A strong upper ridge axis continues to gradually shift
east of the region with southwesterly flow aloft. Surface flow is
currently northerly with speeds mainly 4-8 kts...although coastal
locations may see speeds ranging 10-15 kts. VFR conditions in place
and expected to persist for most terminals throughout the TAF
period. However, increasing onshore flow tonight will bring IFR/LIFR
stratus to coastal areas, such as HQM, by around 04-06Z tonight.
Stratus will spread locally inland tonight to around SHN by
sunrise on Wednesday. VFR conditions expected to resume for these
locations by Wednesday afternoon.

KSEA...Clear skies. Surface winds generally N/NW 5 to 9 knots
backing to light S/SW after 09Z Wednesday morning. North to
northwesterly winds to resume in the mid-afternoon. 33/18

&&

.MARINE...Broad surface ridging over the coastal and offshore
waters will remain in place through the week. Thermally induced
low pressure over the interior of Western Washington will shift
eastward tonight resulting in an increase in onshore flow for the
second half of the week. Small craft advisory westerlies are
expected in the central/east strait tonight, and as such headline
in place there will remain unaltered. A weak weather system
passing well to the north of the area will increase the onshore
flow further on Wednesday with gale force westerlies a strong
possibility in the central/east strait Wednesday evening. Models
remain consistent in bringing low-end gales into this area,
however would be more confident in upgrading to warning if current
headline pans out. As such, will hold off and allow future shifts
to make the decision. A fairly static summer onshore flow pattern
remains Thursday into the weekend for diurnally driven increases
in the westerlies in the strait and occasional small craft
advisory winds/seas over portions of the coastal waters.

Seas generally 4 to 6 ft today and Wednesday before increasing to 6
to 8 ft Thursday. 33/18

&&

.FIRE WEATHER...Another dry and hot day for the interior. Instability
over the Cascades will result in critical fire weather conditions and
a Red Flag Warning remains in effect today for the Cascades. For the
lower elevations of the central and southern Puget Sound relative humidity
values could get as low as the teens late this afternoon. Onshore
flow will bring higher humidities beginning Wednesday.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Heat Advisory until 10 PM PDT this evening for Admiralty Inlet
     Area-Eastern Strait of Juan de Fuca-Lower Chehalis Valley
     Area-Olympics-San Juan County-Southwest Interior-Western
     Skagit County-Western Whatcom County.

     Heat Advisory until 5 PM PDT Wednesday for Bellevue and Vicinity-
     Bremerton and Vicinity-East Puget Sound Lowlands-Everett
     and Vicinity-Hood Canal Area-Seattle and Vicinity-Tacoma
     Area-West Slopes North Cascades and Passes-West Slopes
     North Central Cascades and Passes-West Slopes South Central
     Cascades and Passes.

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

PZ...Small Craft Advisory until 5 AM PDT Wednesday for Central U.S.
     Waters Strait Of Juan De Fuca-East Entrance U.S. Waters
     Strait Of Juan De Fuca.

     Gale Watch from Wednesday afternoon through late Wednesday night
     for Central U.S. Waters Strait Of Juan De Fuca-East
     Entrance U.S. Waters Strait Of Juan De Fuca.

&&

$$