817
FXUS66 KSEW 130306
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
806 PM PDT Fri Jul 12 2024

.UPDATE...
Forecast is on track this evening, with clear skies across Western
Washington except for the stratus hugging the immediate Pacific
Coast. A few showers/storms did build east of the area, primarily
across Okanogan County but continue to push away from the area. A
clear night with lows generally very similar to the past few
nights, from the upper 40s in rural cool spots to near 60 in urban
areas.


&&

.AVIATION...Westerly flow aloft over W WA as zonal aloft continues.
VFR conditions will persist throughout the TAF period for the
majority of area terminals with the exception of HQM, where marine
stratus have already pushed inland, resulting in IFR conditions
there. Any further eastward movement is expected to be minimal, with
no impacts to other terminals expected. HQM should recover to VFR
conditions by early Saturday afternoon...although this break is
expected to only last into the early evening before marine stratus
return.

KSEA...VFR will continue through the TAF period. N/NW winds 5 to 10
knots will become light tonight through Saturday morning before
W/NW winds return in the afternoon.

Mazurkiewicz/18

&&

.MARINE...Surface high pressure continues to be situated offshore
while low pressure remains inland. A small craft advisory continues
over the outer coastal waters for increased northwesterlies. Latest
buoy data continues to show winds on the low side of criteria...with
some spots only meeting thresholds via gusts. Given the sparse data
to work with, however, feel that this is enough to keep the headline
in place unaltered. Diurnal westerlies will persist into early next
week which could result in additional headlines for the Strait from
time to time.

Coastal seas 6 to 8 feet this afternoon with the highest waves
over the coastal waters. Seas will then decrease to 4 to 6 feet
into the weekend and into early next week.

Mazurkiewicz/18

&&

.PREV DISCUSSION... /issued 220 PM PDT Fri Jul 12 2024/

SYNOPSIS...An upper level ridge remains over Western Washington
through the weekend into next week with continued low level
onshore flow. This will maintain above normal temperatures, but
still notably cooler than the start of this week. No rain expected
with only subtle variations in the strength of the marine pushes
each night.

SHORT TERM /TONIGHT THROUGH MONDAY/...Sunny skies continue across
interior Western Washington, while low stratus has been slow to
erode along the coastline. Expect these daily stratus pushes to
move into the coast with temperatures closer to normal in the
areas that see clouds. Meanwhile, temperatures remain above normal
through the interior with temperatures warming a bit on Saturday
to the upper 80s to around 90 as the onshore flow weakens.
Otherwise, a rather persistent pattern remains through the start
of next week.

LONG TERM /TUESDAY THROUGH FRIDAY/...The start of next week looks
largely similar with decent agreement among the ensemble guidance.
This will maintain onshore flow through the week and high temperatures
in the mid to upper 80s through the interior. The guidance does
diverge a little bit later in the week, with some of ensemble
members suggesting a deeper trough over the Pacific approaches the
region. This opens to door to some favorable flow to increase some
convection in the Cascades as a weak front moves toward the area.
Still lower confidence in this scenario with the most likely
outcome is continued dry conditions, but some light precipitation
for at least part of the area can`t be totally ruled out.

AVIATION...Westerly flow aloft over W WA as zonal aloft
continues. VFR persists at all area terminals this afternoon, with the
exception being KHQM where marine stratus continues to create MVFR
conditions. Stratus will return to coastal airfields tonight and
continue through Saturday morning, with MVFR/IFR conditions.
Elsewhere, VFR will persist through the period with clear skies.

KSEA...VFR will continue through the TAF period. N/NW winds 5 to
10 knots will become light tonight through Saturday morning.

Mazurkiewicz

MARINE...Surface high pressure continues to be situated offshore
while low pressure remains inland. A small craft advisory will
continue over the outer coastal waters for increased
northwesterlies. Diurnal westerlies will persist into early next
week with additional headlines for the Strait.

Coastal seas 6 to 8 feet this afternoon with the highest waves
over the coastal waters. Seas will then decrease to 4 to 6 feet
into the weekend and into early next week.

Mazurkiewicz

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 11 AM PDT Saturday for Coastal Waters
     From Cape Flattery To James Island 10 To 60 Nm-Coastal
     Waters From James Island To Point Grenville 10 To 60 Nm-
     Coastal Waters From Point Grenville To Cape Shoalwater 10
     To 60 Nm.

&&

$$