Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
786
FXUS66 KSEW 311531
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
831 AM PDT Sat Oct 31 2026
.UPDATE...
Thunderstorms over the outer coastal waters this morning have
continued to show signs of low-level rotation, and as a result,
a couple Special Marine Warnings have been issued for potential
waterspouts. While these storms continue to be short-lived, a
brief waterspout well offshore cannot be ruled out as these
storms continue. Convective activity will taper off by the mid
afternoon as the upper low weakens and shifts inland.
In addition, fog remains well entrenched over the lowlands of
Lewis and southern Thurston Counties, and a Dense Fog Advisory
will continue for these areas through 11 AM. Otherwise, the
remainder of the forecast remains on track this morning with no
additional updates.
&&
.SYNOPSIS...
Drier conditions are expected over the weekend as an upper low
offshore weakens and moves inland well to the south of the region.
An upper level ridge moving into the region on Sunday will keep
conditions dry and temperatures seasonable across western Washington
into Monday. The first half of next week will remain mostly
dry, with chances of precipitation increasing mid to late week
as a series of systems approaches the Pacific Northwest.
&&
.SHORT TERM /TODAY THROUGH MONDAY/...
An upper level low offshore will continue to bring showers and
some isolated thunderstorms to the coastal waters through the
early morning hours. Showers will gradually taper across the
waters through the day as the low weakens and exits the area.
Otherwise, expect cool conditions for areas across the interior
this morning as skies continue to clear. Morning lows are expected
to approach freezing for many areas south of the Sound, but
particularly across the Chehalis River Valley. Areas of clearing
have also started to see some fog development overnight, so
could even see some spots of dense fog this morning. Morning
temperatures will remain a couple degrees warmer for areas north
of Seattle- however, with temperatures expected to dip into the
mid 30s, could see some areas of frost development as well.
Freeze warnings remain in effect for areas along the Chehalis
River Valley and frost advisories remain in effect for areas
north of Seattle and along the foothills of the Cascades through
mid morning. Any areas of fog are expected to scatter by late
morning.
Overall conditions will be drier today and Sunday as the low
offshore exits the area and an upper level ridge moves into the
region. Cool overnight lows in the 30s will bring areas of
additional frost development to the area on Sunday morning and
moisture in the low levels will likely promote another round of
fog development. High temperatures will be in the low to mid
50s both days.
The upper level ridge axis will push further inland on Monday,
maintaining mostly dry conditions for western Washington for the
start of next week. A few ensemble members do continue to hint
at a weak frontal system brushing the region, which may bring
some light precipitation chances (roughly 20 to 30%) to the
coast through the day. Morning lows will be in the 30s and
afternoon highs will be in the low to mid 50s.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Conditions largely look to remain drier through the first part
of next week, though a splitting system may bring some light
rain to portions of the area on Tuesday. A return to a more
unsettled pattern looks more favorable mid to late week as a
series of systems approaches western Washington. At this time,
a weak system looks to move across the area on Wednesday, with a
stronger system on Friday looking to bring more notable chances
of precipitation. However, it is worth noting that there still
remains a decent spread amongst ensemble solutions for the second
half of the week. Morning lows will be in the mid 30s to mid
40s and afternoon highs will be in the mid to upper 50s
throughout the period.
14
&&
.AVIATION...
Surface low pressure will continue to dig southward off the shore,
with high pressure rebuilding in southern B.C. over the weekend.
Showers with isolated thunderstorms will continue over the coastal
waters through the morning. Dense fog continues across many of the
terminals this morning, generally south of PAE. Expecting to see
improvement after 18Z-20Z to VFR for impacted terminals. Additional
fog/mist development tonight is likely, and may be more widespread
in coverage in the Puget Sound/south interior for another chance of
IFR/LIFR conditions. Light northerly winds around 5 kt or less
increasing to 5-8 kt this afternoon.
KSEA...LIFR conditions this morning with fog impacting the terminal.
Improvement to VFR expected after 18Z and in the worst case scenario
by 20Z. Fog expected Sunday morning with LIFR conditions around 12Z.
Light NE winds this morning becoming more N/NW this afternoon around
5-8 kt. Winds become NE this evening at 4-6 kt.
HPR/29
&&
.MARINE...
Showers continue to move across the coastal waters this morning.
Rotation has been observed with these storms. Therefore, brief
waterspouts cannot be ruled out.
A surface low will begin to dig southward across the waters today.
High pressure will rebuild inland. This will lead to a brief window
of offshore flow through the weekend, with gustier winds to 20 kt
this morning in the coastal waters diminishing quickly. Shower and
thunderstorm activity will continue in the coastal waters through
the morning, but will wind down through the day. Hazardous winds are
not expected at this time through Wednesday, when the next system
passes through. Another system may also skirt the waters late next
week/weekend.
Seas will hover at 4-6 ft through the weekend, but build back to 10
to 11 ft Monday as swells increase out of the west. Seas drop back
down to 6-8 ft Tuesday through Thursday but build back to 10-14 ft
late Thursday through next weekend.
HPR/29
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Frost Advisory until 9 AM PDT this morning for Downtown
Everett / Marysville Area-Eastern Kitsap County-Eastern
Strait of Juan de Fuca-Eastside-Foothills and Valleys of
Central King County-Foothills and Valleys of Snohomish
and Northern King Counties-Foothills and Valleys of the
North Cascades-Lake Crescent Area Including US 101-
Lowlands of Western Skagit and Northwestern Snohomish
Counties-Lowlands of Western Whatcom County-Shoreline /
Lynnwood / South Everett Area-Western Strait of Juan de
Fuca.
Dense Fog Advisory until 11 AM PDT this morning for Lowlands
of Lewis and Southern Thurston Counties-Olympia and
Southern Puget Sound.
Freeze Warning until 9 AM PDT this morning for Lowlands of
Lewis and Southern Thurston Counties-Middle Chehalis
River Valley.
PZ...None.
&&
$$
NWS SEW Office Area Forecast Discussion