Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
000
FXUS66 KSEW 311648
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
848 AM PST Tue Jan 31 2023
.UPDATE...Precipitation associated with a weak front slid through
Western Washington early this morning for areas of flurries and
light snow showers. Most areas that observed snow recorded trace
amounts, the exception being North Interior with areas of San
Juan Islands, Whatcom County, and adjacent areas recording light
snowfall amounts. The bulk of the precipitation has slid east of
the interior, for drier weather for most through the afternoon. A
chance of snow or rain/snow mix continues into this afternoon for
Skagit/Whatcom County, little to no additional accumulation is
expected. Temperatures will slowly moderate today into upper 30s
to mid 40s.
&&
.SYNOPSIS...A couple of weak weather systems will bring light
precipitation to the Olympics and North Interior into Wednesday. A
weak ridge of high pressure will give mainly dry weather across
the area Wednesday night through Thursday afternoon. A series of
fronts will produce periods of lowland rain and mountain snow from
Thursday night into early next week.
&&
.SHORT TERM /TODAY THROUGH THURSDAY/...Abundant high and mid level
clouds blanket Western Washington early this morning as a warm
front nudges toward Vancouver Island. The air mass remains pretty
dry in the lower levels across the area and little in the way of
precip is expected from this system apart from a shower or two
over the Olympic Peninsula and near the Canadian border. A
secondary weak system will brush the area tonight into early
Wednesday keeping skies mostly cloudy, but precip chances will
again remain limited mostly to the Olympic Peninsula and interior
areas north of Seattle. The air mass will initially be cold
enough for a few flurries up in Whatcom and Skagit counties this
morning, but impactful accumulation is not expected. High
temperatures will remain a little below normal today with lowland
highs in the lower to mid 40s, but will warm into the mid 40s to
near 50 on Wednesday. The cloud cover will keep overnight lows
warmer as well...mostly in the 30s.
A deepening upper trough offshore will amplify a downstream upper
ridge axis as it shifts eastward across the area Wednesday night
into early Thursday. This should keep most of the area on the dry
side, albeit temporarily. Interior areas could manage some
filtered sunshine early Thursday before clouds increase again. Rain
out ahead of an approaching frontal system will reach coastal
areas by Thursday evening and the interior overnight.
.LONG TERM /FRIDAY THROUGH MONDAY/...The weekend heralds a return
to typical mid-winter weather as we generally know it in the
Pacific Northwest. Broad upper troughing over the northeast
Pacific will send a series of frontal systems through the area for
periods of lowland rain and mountain snow. A frontal system
Friday afternoon/evening presently appears to be the strongest of
the bunch both in terms of QPF and winds...which amounts to a
damp and breezy end to the week. Snow levels Friday through the
weekend will generally run in the 2500 to 3500 foot range.
Ensemble plots generally point toward seasonable temps and precip
as we move into next week. The longwave pattern lacks any real
noteworthy features with 5 and 7 day height anomalies showing
zonal flow across the area. 27
&&
.AVIATION...Northwesterly flow aloft as an upper level ridge
continues to flatten, with a weak warm front passing through the
region this morning. This will continue to spread increasing mid
level clouds with ceilings down to around 4500 ft in some
locations and some light snow showers in the northern interior,
especially affecting KBLI. Light precipitation will taper by early
afternoon. Otherwise, continued VFR conditions are expected
through the period with generally light east or southeast surface
winds across the region.
KSEA...A mix between MVFR/IFR conditions as light banding of snow
dissipates over the terminal. Expect ceilings to rebound back VFR
by the early afternoon with southeasterly winds generally around
5 to 7 kts.
Mazurkiewicz
&&
.MARINE...Light winds continue through today across the local
waters with weak high pressure over the coastal waters and a weak
disturbance clipping the far north inland waters. Winds will become
increasing southerly later today and Wednesday as a weak frontal
system approaches the coastal waters. Expect to see winds to reach
the 20-25 kt range over the coastal waters later Wednesday,
especially north of Point Grenville and beyond about 25 nm from
shore. . Considerably higher chances for advisory strength winds
over all waters Wednesday night and Thursday, however, as a stronger
front reaches the area. Similarly, latest probabilities of sustained
gales over the coastal waters have increased to 60% over the outer
coastal waters for late Thursday. Meanwhile, seas generally holding
around 4 to 5 ft over the coastal waters for the next few day or
two, dominated by a long period west swell. However, seas likely
build considerable Thursday afternoon and evening, with combined
seas reaching at least 15 ft. Cullen
&&
.HYDROLOGY...No river flooding is expected through the next seven
days.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...None.
&&
$$
NWS SEW Office Area Forecast Discussion