Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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000 FXUS66 KSEW 151120 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 320 AM PST Thu Feb 15 2018 .SYNOPSIS...
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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.
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&& .SHORT TERM...
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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
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&& .AVIATION...
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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 KSEA...
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&& .MARINE...
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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
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&& .HYDROLOGY...River flooding is not expected for the next 7 days. && .SEW WATCHES/WARNINGS/ADVISORIES...
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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 Counties. 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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&& $$ www.weather.gov/seattle

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