Marine Weather and Tide Forecast for Shelton, WA

SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/
An atmospheric river will continue to pull in warm, moist air from the deep Pacific, resulting in steady rainfall across western Washington over the next several days. The warmer air has allowed snow levels to rise as high as 8000 feet, with nearly all precipitation over the mountains falling as rain. The heaviest rain will be focused over the Olympic Peninsula and Cascades, where upwards of 6 to 10 inches of rainfall are possible between today and Friday. The rain-on-snow and snow melt will contribute to significant runoff in addition to the incoming rainfall, increasing the risk of river flooding over the mountains. The lowlands are also on track to see 1 to 2 inches of rain through Friday, which may result in roadway ponding and localized nuisance flooding. The risk for landslides will also increase towards the end of the week as a result of the incoming rainfall and snow melt. For more information on river flooding, see the HYDROLOGY section below.

In addition to wet conditions, western Washington will see mild temperatures for the rest of the work week with highs in the mid to upper 50s across the lowlands. Overnight low temperatures will also remain elevated, with lows bottoming out around 50 degrees for much of the lowlands. Southerly winds will also remain breezy at times through Friday, with gusts ranging between 20 to 35 mph. The strongest winds will occur along the Pacific Coast and from Everett northwards across the Interior.

LONG TERM /FRIDAY THROUGH TUESDAY/
By Friday night, a trailing cold front behind the atmospheric river system will push the bulk of the remaining precipitation southward towards southern Oregon. Temperatures across western Washington will cool off several degrees, with snow levels lowering to 1500-2500 feet. Light snow will linger over the mountains into Saturday and Sunday as the lowlands briefly dry out under cloudy skies. Models remain in good agreement over another wet weather system moving into the region by the start of next week, though the details remain fairly uncertain.

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AVIATION
Strong westerly flow aloft will continue tonight across Western Washington as a moist air mass continues to funnel rain into the region ahead of a stalled frontal boundary over British Columbia.
Most terminals are reporting VFR conditions at the time of this writing with only HQM, PWT and PAE currently reporting MVFR/IFR conditions. It is worth noting that terminals currently reporting VFR do have FEW-SCT clouds at MVFR/IFR levels and have bounced back and forth from VFR to MVFR at times this afternoon. As precip persists, adding more low-level moisture to the area, widespread MVFR to IFR conditions are expected to emerge between 03-06Z this evening and persist for the remainder of the TAF period. Persistent precip will also impact visibility throughout the CWA, introducing limitations from time to time. Southerly winds generally 5-10 kt.
Breezy conditions expected from PAE northwards with sustained speeds 10-15 kt and gusts 20-25 kt.

KSEA...Currently reporting VFR cigs, however given the pattern of rising and lowering cigs earlier this afternoon, difficult to put too much stock in how long these higher cigs will continue. MVFR conditions expected to emerge by 06Z and if current radar trends hold up, with lighter echoes expected over the terminal in the near term, this timing may be on track. In agreement with inherited forecast that the threat for IFR conditions, while not gone entirely, seems low with low-end MVFR continuing to be favored as precip picks up overnight. Will continue to monitor model output before making decision for 06Z TAFs. S/SW winds 5-7 kt this evening and overnight before increasing to 8-10 kt Wednesday morning.

29/18

MARINE
Southerly flow will continue across the waters into Wednesday as a frontal boundary remains stalled in British Columbia. As a result, small craft winds and gusts will continue across interior waters today and into Wednesday morning. In addition, a Small Craft Advisory continues across the coastal waters for seas. Seas will continue to ease tonight and expected to be below 10 ft by Wednesday morning. Small craft winds are likely across the coastal waters Wednesday night into Thursday, with current probabilities greater than 80%. A cold front will move over area waters on Friday through Saturday. As the front passes through the Strait of Juan de Fuca , there is the potential (45-70% chance) for small craft winds for the Western and Central Strait.

29/18

HYDROLOGY
An atmospheric river will continue to bring steady rainfall to western Washington through Friday. Snow levels will remain around 7000-8000 feet, falling as mostly rain over higher terrain. Rainfall totals over the Olympic Peninsula and Cascades has slightly increased, with a total of 6 to 10 inches over the Olympic Mountains and Central and Northern Cascades through Friday. Elsewhere, rainfall totals around 1 to 3 inches can be expected.

The combination of steady rain, elevated snow levels, and low level snow melt will put pressure on area rivers into the weekend. Rivers in the Cascades from King County northward have the highest chance of reaching flood stage, with the Snoqualmie, Snohomish, and Tolt River forecasts all creeping close to Major Flood stage between late Wednesday and Thursday. The Skagit River is also now forecast to flood by Thursday and rise to near Major Flood stage by Friday. In addition, the flood- prone Skokomish River in Mason County is forecast to enter Minor Flood stage on Wednesday and crest once again in Minor Flood stage on Friday. Flood Watches remain in effect for Mason County and for King County northward, where flooding is most likely to occur on area rivers late Wednesday into Thursday, with impacts possible into the weekend.

The snow melt factor is complicating river forecasts, as the melting snow off of the mountains could contribute an additional 10 to 15 percent of the total water in the system. This added variable could enhance the potential flooding later in the week.

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SEW WATCHES/WARNINGS/ADVISORIES
WA...Flood Watch from Wednesday afternoon through Friday afternoon for Cascades of Snohomish and Northern King Counties- Cascades of Southern King County-Cascades of Whatcom and Skagit Counties-City of Seattle-Downtown Everett / Marysville Area-Eastside-Foothills and Valleys of Central King County-Foothills and Valleys of Pierce and Southern King Counties-Foothills and Valleys of Snohomish and Northern King Counties-Foothills and Valleys of the North Cascades-Lowlands of Pierce and Southern King Counties- Lowlands of Western Skagit and Northwestern Snohomish Counties-Lowlands of Western Whatcom County-Shoreline / Lynnwood / South Everett Area.

Flood Watch through Friday afternoon for Foothills of the Western and Southern Olympic Peninsula-Middle Chehalis River Valley-Olympia and Southern Puget Sound-Olympics- Southern Hood Canal-Willapa and Black Hills.

PZ...Small Craft Advisory until 5 AM PDT Wednesday 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- Northern Inland Waters Including The San Juan Islands- Puget Sound and Hood Canal-West Entrance U.S. Waters Strait Of Juan De Fuca.