Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
000
FXUS66 KSEW 251621
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
821 AM PST Mon Jan 25 2021
.UPDATE /MORNING UPDATE/...Clouds will scatter out slightly later
this afternoon. Highs are expected to be in the mid 40s throughout
the Western Washington area the next few days. We are still
monitoring the conditions for possible low land snow Tuesday night
into Thursday. With cold air aloft and at the surface, and
dropping snow levels, most of Western Washington has the potential
to see some flakes falling Tuesday night. As temperatures begin to
rise come Wednesday morning, we do not foresee much accumulation
happening for the majority of the lowlands. If you are higher up
in the hills or in Northern Whatcom county, you will likely see a
nice dusting.
Butwin
&&
.SYNOPSIS...A front will reach the West Coast tonight--the
heavier precipitation will go into California. Additional weather
systems will arrive late in the week or over the weekend. The snow
level will be low through the week for a chance of spotty light
snow at times in the lowlands with gradual warming next weekend.
&&
.SHORT TERM /TODAY THROUGH WEDNESDAY/...Scattered showers will
linger today, especially north of Seattle with a weak upper trough
over the area. Some sun breaks are possible as well. Snow levels
will be 1000-1500 feet. The air aloft will be pretty cold
resulting in steep lapse rates and some instability, especially
near the coast where an isolated rumble of thunder is possible.
Highs will be a few degrees below normal - lower to mid 40s.
The upper trough will weaken and shift inland tonight with an
upper ridge briefly moving over the area on Tuesday. This should
dry things out although rain will return again at the coast
Tuesday afternoon as the next frontal system nears.
The aforementioned frontal system will move through the area
Tuesday night but most of the associated precipitation is heading
south. Snow levels will once again be low for a threat of snow
most areas. However, precipitation looks light and only minor
accumulations (less than an inch), if any, are expected. This is
backed up by ensemble solutions which show just a few tenths of an
inch of snow for most of the area on average.
Another baggy upper trough will be over the area on Wednesday for
some lingering light showers. Snow levels will rise to 500-1000
feet in the afternoon largely ending the minor lowland snow
accumulation threat for the day. Schneider
.LONG TERM /THURSDAY THROUGH SUNDAY/...A nondescript upper trough
will be over the area on Thursday for a few showers will snow
levels generally 1000-1500 feet. A weak upper ridge will briefly
move over the area on Friday for largely dry day. Snow levels
will remain around 1000 feet and a few showers will linger.
A more interesting scenario is setting up for Friday
night/early Saturday morning. A wetter frontal system is forecast
to overrun the cooler air currently in place. Low level flow will
initially be somewhat easterly. This could bring some actual
accumulating snow to favored areas like Hood Canal and the Kitsap
Peninsula but its still several days out so confidence in the
details is pretty low for now.
The lowland snow threat should end later Saturday as low level
southerly flow increases Saturday and continues into Sunday. The
Friday night frontal system will quickly be followed by another
weather system Saturday night for a relatively wet weekend.
Schneider
&&
.AVIATION...Upper level trough near the coast weakens and moves
inland Tuesday. Southwest flow aloft. Areas of MVFR cigs are mainly
around Puget Sound this morning, there is some stratus with bases
around 010 from Skagit county into the San Juans. Conditions should
improve into the afternoon as the air slowly dries. Showers with the
upper trough should stay near the south coast. Scattered showers
especially near the coast--although there are showers around Western
Skagit and Whatcom county this morning and some wet snow will
probably mix in at times. 19
KSEA...Ceilings improving into the afternoon and the clouds might
scatter out later today. Light south wind for now, light gradients
tonight with light and variable wind becoming easterly Tuesday.
&&
.MARINE...Weak surface low dissipating over the waters
today. Another front will arrive Tuesday night and move inland south
of the area. Surface low center remaining over the Oregon coastal
waters Wednesday and Wednesday night. Weak offshore flow Thursday
into Friday.
Small craft advisories remain in effect for 10 to 15 foot seas
over the coastal waters and at the West Entrance to the Strait of
Juan De Fuca through tonight. Small craft advisory southeast winds
developing over the coastal waters Tuesday morning with gales
possible Tuesday afternoon and evening. Small craft advisory winds
possible for the Strait and Northern portion of the waters
Tuesday as well. winds and seas easing all waters Wednesday.
&&
.HYDROLOGY...River flooding is not expected for the next 7 days.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Gale Watch from Tuesday afternoon through late Tuesday night 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.
Small Craft Advisory until noon PST Tuesday 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.
Small Craft Advisory until 6 AM PST Tuesday for Grays Harbor Bar.
Small Craft Advisory until 6 PM PST Tuesday for West Entrance
U.S. Waters Strait Of Juan De Fuca.
&&
$$
www.weather.gov/seattle
NWS SEW Office Area Forecast Discussion