Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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FXUS66 KSEW 151120

Area Forecast Discussion
National Weather Service Seattle WA
320 AM PST Thu Feb 15 2018

.SYNOPSIS...A front will bring rain tonight and Friday. A much
stronger frontal system will bring more rain along with windy
conditions and heavy snow in the mountains Friday night and
Saturday. Fraser outflow will develop Sunday with colder
temperatures and possible lowland snow showers. It will be dry
and cold early next week with offshore flow.


.SHORT TERM...A few showers will linger today in somewhat moist
onshore flow. A front will bring rain tonight and Friday with some
breezy to locally windy conditions. Advisory amounts of snow look
likely for the Cascades with fairly low snow levels. There will
be a modest and brief lull in between weather systems Friday
evening. A vigorous frontal system will then bring another round
of rain later Friday night and Saturday. This system looks a notch
windier - probably advisory levels for some areas. It will also
be wetter with heavy snow possible for the mountains. Schneider

.LONG TERM...A cold upper trough will settle over the area Sunday.
At the same time, strong Fraser outflow will develop, pushing a
modified arctic front south through Western Washington during the
day. There could be some snow in the lowlands, especially along
the arctic boundary that pushes south but it is too far out to
pin down details like timing or accumulations. Dry northerly flow
aloft will prevail Monday through Wednesday. Fraser outflow will
ease Monday but cold air will remain in place. A weak system
dropping down from the north could bring some rain or snow showers
Wednesday. Schneider


.AVIATION...Northerly flow aloft becoming northwesterly this
morning with the northwesterly flow aloft continuing into Friday.
Rain out ahead of an approaching warm front will move into the
tonight into the early morning hours on Friday.

Wide variety of ceilings this morning with mostly MVFR between
Olympia and Bellingham with some isolated IFR/LIFR in the Bremerton
and Shelton and VFR over the remainder of the area. Ceilings will
improve to VFR over most of the area later this morning into the
afternoon hours with ceilings lowering back down to MVFR overnight
with light rain. Local visibilities 3-5sm after midnight with the
light rain.

KSEA...Scattered to broken deck around 1000 feet early this morning
will scatter out by mid morning with just mid and high level clouds
this afternoon. Ceilings lowering back down to near 2000 feet after
midnight with light rain. South to southeast wind 4 to 8 knots into
Friday morning. Felton



.MARINE...Moderate northerly flow will gradually transition
to weaker onshore flow by mid-morning. Current observations still
falling within low-end borderline when it comes to inherited
headline thresholds and as such will allow SCAs in place to run
their course. A weak frontal system will move across the area on
Friday...resulting in a round of SCA caliber winds for most of the
area waters. This will be followed by a much stronger system for the
weekend which has the potential to bring gale force winds to parts
of the area. SMR


.HYDROLOGY...River flooding is not expected for the next 7 days.


WA...Winter Weather Advisory from midnight tonight to 7 PM PST Friday
     for Cascades of Pierce and Lewis Counties-Cascades of
     Snohomish and King Counties-Cascades of Whatcom and Skagit

PZ...Small Craft Advisory until 9 AM PST this morning for Coastal
     Waters From Cape Flattery To James Island 10 To 60 Nm-
     Coastal Waters From James Island To Point Grenville 10 To
     60 Nm-Coastal Waters From Point Grenville To Cape
     Shoalwater 10 To 60 Nm.

     Small Craft Advisory for rough bar until 9 AM PST this morning
     for Grays Harbor Bar.

     Small Craft Advisory until 6 AM PST early this morning for
     Coastal Waters From Cape Flattery To James Island Out 10 Nm-
     Coastal Waters From James Island To Point Grenville Out 10
     Nm-Coastal Waters From Point Grenville To Cape Shoalwater
     Out 10 Nm.


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