Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
290
FXUS66 KSEW 110520
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
920 PM PST Mon Dec 10 2018
.SYNOPSIS...A series of vigorous fronts will move through the
area over the next week. The first one will arrive on Tuesday with
locally windy conditions and heavy mountain snow. There will be a
lull on Wednesday followed by the next system Wednesday night and
Thursday. This system will hang up over the area before pushing
inland later Friday. Another system will arrive on Sunday.
&&
.SHORT TERM...A vigorous frontal system will bring rain, wind,
and mountain snow later tonight and Tuesday. Wind advisories are
up for the usual southeast sucker locations - coast and Northwest
Interior. Isolated high wind is not out of the question for the
San Juan Islands and Western Whatcom county for a few hours Tuesday
morning. The Cascades will get heavy snow Tuesday and Tuesday
night. Snow levels will start out 2500-3000 feet but models show
snow levels rising to 4000-4500 feet Tuesday afternoon and
evening which means snow will probably turn to rain at Snoqualmie
Pass and perhaps even at Stevens Pass. About a foot of new snow is
expected at Snoqualmie Pass with up to two feet at Stevens Pass
and 2-3 feet at Mount Baker and Paradise. The winter storm watch
has been upgraded to a warning.
There will be a brief lull in between fronts on Wednesday with
the next frontal system fast approaching. This aforementioned
second frontal system will bring another round of rain, wind, and
mountain snow to the area Wednesday night and Thursday. Schneider
.LONG TERM...A frontal system will push inland on Friday with
rain, wind, and mountain snow tapering. It could get rather windy
on Friday as a deep surface low tracks onshore but models are
having a tough time agreeing on the track and strength of the low
so how windy it will get is very uncertain for now. There will be
a break in between fronts on Saturday then another front on
Sunday. This front is splitting as it moves onshore and looks like
a garden variety December system. Yet another frontal system will
be moving into the area later Monday. This system could
potentially be the wettest of the week. Schneider
&&
.AVIATION...An upper trough is moving inland, northwest flow aloft
will become southwest and increase Tuesday with the next frontal
system. Mid level clouds continue to spread across the area this
evening while main area of rain is beginning to move onshore with
MVFR conditions along the coast. As the system moves onshore,
MVFR ceilings and rain will continue to spread inland. Could
briefly see a few spots drop into IFR ceilings as system moves
across. Gusty SSE surface winds will develop--especially coastal
areas and the north interior of Western Washington, then turn more
southwesterly later in the day Tuesday with the frontal passage.
KSEA...Ceilings will continue to lower overnight with rain moving
into the terminal after 8-9Z. Rain will continue throughout the
day Tuesday with MVFR conditions likely. On Tuesday winds at 5000
feet will be SW near 50 knots and blustery southerly surface
winds will pick up-- especially in the afternoon as the front
passes and winds shift from SE to SSW. CEO
&&
.MARINE...Next system is moving onshore tonight into Tuesday and
will bring gusty winds. Gale warnings are in effect for all
waters except the central Strait of Juan de Fuca and Puget Sound--
where the wind should stay in the small craft advisory category.
After a break later Tuesday night and Wednesday morning another
vigorous front will arrive Wednesday night into Thursday with
another strong system on Friday. Small craft and/or gale warning
conditions will be present from time-to-time during the rest of
the week. CEO
&&
.HYDROLOGY...A series of storms will cross over the region during
this next week, bringing periods of rain roughly every other day.
This will drive the rivers back up again with the cumulative effect
pushing the Skokomish River in Mason county likely over flood stage
Tuesday night and maybe over moderate flood stage late this week -
and possibly other rivers by that time as well. There is a flood
watch out for Mason County and the Skokomish River for Tuesday
night. The best chance for flooding in general will probably be
Friday when a frontal system could hang up over the area. One major
factor working against flooding on many rivers will be the
moderately low snow levels (4000 to 5000 ft dropping to 3000 ft
Friday) which might limit storm runoff. jbb
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Winter Storm Warning from 4 AM Tuesday to 4 AM PST Wednesday for
Cascades of Pierce and Lewis Counties-Cascades of Snohomish
and King Counties-Cascades of Whatcom and Skagit Counties.
Flood Watch from Tuesday morning through Tuesday evening for
Hood Canal Area-Lower Chehalis Valley Area-Olympics.
Wind Advisory until 1 PM PST Tuesday for Admiralty Inlet Area-
San Juan County-Western Skagit County-Western Whatcom
County.
Wind Advisory until 10 AM PST Tuesday for Central Coast-North
Coast.
PZ...Small Craft Advisory for rough bar until 2 AM PST Wednesday for
Grays Harbor Bar.
Gale Warning until 1 PM PST Tuesday for Admiralty Inlet-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-East Entrance U.S. Waters
Strait Of Juan De Fuca-Northern Inland Waters Including The
San Juan Islands-West Entrance U.S. Waters Strait Of Juan
De Fuca.
Small Craft Advisory from 1 AM Tuesday to 2 AM PST Wednesday for
Central U.S. Waters Strait Of Juan De Fuca.
Small Craft Advisory from 1 AM to 10 PM PST Tuesday for Puget
Sound and Hood Canal.
&&
$$
www.weather.gov/seattle
NWS SEW Office Area Forecast Discussion