Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
679
FXUS66 KSEW 231542
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
842 AM PDT Tue Oct 23 2018
.SYNOPSIS...One last fog episode this morning before a weakening
front will arrive this afternoon and evening. This may not bring
much rain but should turn winds southerly and clear out most of
the fog. A stronger system will arrive on Thursday with wet
weather continuing into Friday. After a break on Saturday,
another front will reach the area on Sunday.
&&
.SHORT TERM...Widespread dense fog continues this morning over the
interior lowlands due to light winds and poor mixing. A Dense Fog
Advisory remains in effect through the morning hours for areas
near the I-5 corridor. Still expecting improving visibilities
later this morning into the early afternoon ad southerly winds
increase ahead of incoming frontal system.
Weak cold front will approach the coast this afternoon, spreading
showers inland this evening and tonight. System will weaken as it
moves inland so some areas may not see any showers at all.
Accumulations elsewhere will remain light. Air quality will
improve as system moves through though. Temperatures this
afternoon will be similar to yesterday.
Wednesday should be mainly dry with a brief break in between
systems. Temperatures will warm a few degrees though cloud cover
will hang around. Next system arrives Thursday with precipitation
continuing into Friday. This appears to be a tad bit stronger and
wetter so more widespread accumulations are expected. Though track
of the center of the low will be NE into northern BC, breezy
winds look likely along the coast and north interior. CEO
.LONG TERM FROM PREVIOUS DISCUSSION...The forecast models are
showing another break in the weather on Saturday as a weak upper
level ridge passes through. Rain will likely return on Sunday as a
trough forms offshore then shifts inland. This system is cooler
and will knock snow levels down in the mountains - down to around
5,500 feet Sunday night. The forecast will remain cool and showery
through early next week as the trough lingers over the Pac NW.
Temperature trends will remain slightly cooler than normal. 33
&&
.AVIATION...Moderate southerly flow aloft today will become westerly
tonight as a weak front dissipates over the region. At the surface,
southerly winds will slowly develop today, with a light onshore push
expected this evening. The air mass is stable and dry except for
surface fog trapped by an inversion. Mid and high level clouds will
increase over the interior this afternoon and evening, bringing
deeper moisture and a chance of showers to the region.
Ceilings are generally LIFR over Western Washington in fog. The
approaching front will induce light southerly flow, allowing the fog
to slowly lift into a stratus deck or perhaps to dissipate.
Conditions will be a mix of IFR, MVFR and scattered low clouds
later this morning into the afternoon. Light rain will reach the
coast in the early afternoon, then spread inland by early evening.
Mostly VFR conditions are expected with a few pockets of MVFR as
light showers are expected this evening and overnight.
KSEA...LIFR conditions in fog will continue this morning. Slow
improvement is expected to begin 18Z, with perhaps MVFR conditions by
21Z. Mid and high level clouds will arrive in the afternoon. Light
rain showers are possible this evening. Southerly wind 6-10 kt. CHB
.MARINE...A weak front will reach the coast today, then dissipate as
it moves inland tonight. Small craft advisory level southerly winds
are likely on the coast through this evening, and an advisory is in
effect. Winds should remain below 20 kt over the inland waters. A
stronger front is forecast to arrive late Wednesday and Thursday,
with small craft advisory winds over the coast and some inland
waters. A warm front on Friday will increase southerly winds. CHB
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Dense Fog Advisory until 11 AM PDT this morning for Bellevue and
Vicinity-Bremerton and Vicinity-Everett and Vicinity-
Seattle and Vicinity-Southwest Interior-Tacoma Area.
PZ...Small Craft Advisory until 11 PM PDT this evening for Coastal
Waters From Cape Flattery To James Island 10 To 60 Nm-
Coastal Waters From Cape Flattery To James Island Out 10 Nm-
Coastal Waters From James Island To Point Grenville 10 To
60 Nm-Coastal Waters From James Island To Point Grenville
Out 10 Nm-Coastal Waters From Point Grenville To Cape
Shoalwater 10 To 60 Nm-Coastal Waters From Point Grenville
To Cape Shoalwater Out 10 Nm.
&&
$$
www.weather.gov/seattle
NWS SEW Office Area Forecast Discussion