Marine Weather and Tide Forecast for Ruston, WA

SHORT TERM /TODAY THROUGH TUESDAY/
Forecast is on track for the morning update (only minor changes were made to the aviation discussion below). HPR

A brief break in the active weather pattern continues early this morning, with drier conditions across western Washington. Current temperatures across the region are mostly in the 30s, with a few spots across the southern Sound reporting temperatures just below freezing. A couple spots may see some patchy fog/freezing fog develop early this morning with light winds and residual moisture in the low levels, but expect the mid and high clouds streaming in overhead to hinder any widespread development. With morning lows near freezing in spots and conditions still damp on some area roadways, could see some slick spots on the roads across the region this morning.

A warm front, associated with an atmospheric river moving into British Columbia, will brush the region today and bring the next round of precipitation to western Washington. A few showers out ahead of the front may briefly bring a rain/snow mix to areas along the coast early this morning, but expect precipitation to transition over to rain by 18Z as the front approaches and snow levels start to rise. Rain will make its way inland into the interior lowlands this afternoon and evening, with snow levels rising between 5500-6500 ft for most of the area by tonight. Snow levels will be slow to rise across the far northern Cascades, however, and look to remain between 3000-4500 ft into early Monday. This could bring an additional 8 inches of snow to portions of the Whatcom and Skagit county Cascades tonight into Monday morning before snow levels rise to 7000-8000 ft. Amounts will be lower for the central Cascades, with the mountain passes likely only seeing 1-4 inches of snow into Monday before snow levels rise above the passes.

Precipitation will then continue into Monday, with the bulk of the moisture still positioned over British Columbia. For western Washington, the highest QPF will generally remain over the northern two-thirds of the area (primarily over the North Coast, Olympics, and the Cascades from King County northward). Latest guidance has the axis of moisture then briefly shifting a bit further northward on Monday afternoon and evening, before it sags and sinks down over the area on Tuesday and brings more widespread precipitation to western Washington as a whole. The main concern throughout the week will be potential hydrological impacts from higher snow levels and from rain falling on recent snow in the mountains. For more info on river flooding, see the hydrology section below. Temperatures will warm throughout the week, with afternoon highs expected to be in the upper 50s and morning lows to be in the mid to upper 40s.

LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/
The warm and wet pattern will continue throughout the week, with the atmospheric river remaining positioned over the region and bringing additional rounds of moderate precipitation to the mountains and coast. While the position of the moisture axis will still fluctuate throughout the week, expect overall conditions to remain wet and unsettled across western Washington through Friday. Temperatures will be warm throughout the week, with afternoon highs generally expected to be in the 50s to low 60s and morning lows expected to be in the 40s to low 50s. At this time, it looks like another, weaker system may follow on the heels of the atmospheric river and move into the area next weekend.

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AVIATION
Northwesterly flow aloft as upper level ridging continues to build over the eastern Pacific. Surface winds largely light and variable with speeds less than 5 kts. VFR conditions in place areawide with mid and high clouds overhead.
Light warm-frontal radar returns are showing up this morning along the northern Pacific coast, but the interior terminals will have to wait until later this afternoon for rain. Typical locations more prone to lower cigs, like OLM, will run the risk for IFR conditions this morning. Surface winds will be light and southeasterly throughout the period.

KSEA...VFR conditions continue this morning with light flow at 5-6 kts. The warm front offshore will bring rain into the terminal between 00Z-06Z with MVFR cigs. 33/21

MARINE
Southerly flow will increase today as a strong warm front shifts north into southern British Columbia. SCA winds continuing for the coast through Monday afternoon. Moderate south winds will continue into Monday and Tuesday with Small Craft Advisories possible for the interior waters. Seas will build to 10-12 ft by Tuesday.

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HYDROLOGY
River flooding continues for rivers across the Chehalis basin this morning. The Chehalis near Grand Mound has crested and will continue to recede today, while the Chehalis at Porter continues to rise and is expected to crest this afternoon and start to recede tonight.

Attention then turns to an atmospheric river moving into the region this week. While the bulk of the moisture will initially move into British Columbia, it will gradually sag southward into our area by Tuesday and will bring periods of rain through much of the week.
Higher snow levels and rain on recent snows in the mountains could bring additional flooding concerns to portions of the area as several rivers are forecast to rise into Action Stage. For now, the only river forecast to reach flood stage is the Skokomish River- but river forecasts will bear watching over the coming days.

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SEW WATCHES/WARNINGS/ADVISORIES
WA...Winter Weather Advisory from 5 PM this afternoon to 9 AM PDT Monday for Cascades of Whatcom and Skagit Counties.

PZ...Small Craft Advisory until 5 PM PDT Monday 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.