000
FXUS66 KSEW 022118
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
220 PM PDT Sun Oct 2 2022

.SYNOPSIS...An upper ridge will keep weather systems away from
the area through next weekend. Coastal marine layer fog and low
clouds will increase through midweek--pushing into the interior of
Western Washington Tuesday and Wednesday.

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...The upper ridge axis
shifts east a little and the OTH-SEA is already +1mb, so coastal low
clouds and fog will increase. For the interior of Western Washington
there should still only be patchy fog Monday morning but for Tuesday
and Wednesday the fog and low clouds should be more widespread. High
temps should be warm again on Monday up and down the I-5 corridor,
but with morning fog and low clouds will fall off a notch Tuesday
and Wednesday. 19

.LONG TERM /THURSDAY THROUGH SUNDAY/...The upper ridge shifts
around but no weather systems approach. The forecast has high temps
well into the 70s for the interior of Western Washington each day,
and that seems fine so long as the marine air is shallow. A look at
the wrfgfs lowest level cloud forecast suggests that the marine air
will be deepest midweek and then becomes shallower through next
weekend. 19

&&

.AVIATION...VFR conditions continuing for most area terminals this
afternoon, with mostly clear skies. Haze from wildfire smoke will
remain in the area (primarily from KPAE to KBFI). No impacts to
visibility are expected from the smoke. Westerly winds at the coast
will continue to increase at KHQM bringing in marine stratus and fog
to the terminal this afternoon. With light onshore flow tonight,
patchy fog and marine stratus will make their return to the area.
Any low clouds that form during the overnight should mix out by 18
UTC tomorrow, with the exception being the at the coast.

KSEA...Northerly winds will continue though the rest of the day and
are expected to ease during the overnight. Chance of patchy fog
forming after 12 UTC Monday. Any fog that forms over the terminal is
expected to mix out by 18 UTC.

Butwin


&&

.MARINE...Southerly winds over the coastal waters will become more
widespread through the rest of today. Winds over the inland waters
will remain light through tomorrow. Expect marine fog to increase
during the overnight and into tomorrow morning. Fog over the inland
waters will generally be patchy and mix out by mid morning.
Westerly winds will increase throughout the afternoon and evening.
No marine headlines are anticipated until maybe Tuesday when there
is the potential for a small craft advisory down the Strait of Juan
de Fuca.

Butwin

&&

.FIRE WEATHER...Warm and dry, humidity will remain low in the
mountains through Monday. Fire weather conditions will be elevated
in the warm afternoon hours critical fire weather conditions are not
likely due to light winds. The cross Cascade gradient is negligible
and the northerly gradient has relaxed, so any breezes will be
localized and driven by the terrain and daytime heating. As we get
into Tuesday and Wednesday, the lowlands will have night and morning
low clouds and fog, and by Wednesday morning that humidity should
spread into the mountains as well--but only for a couple of days.
The marine air should be shallow again Thursday through Sunday. 19

&&

.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...None.

&&

$$

NWS SEW Office Area Forecast Discussion