Marine Weather and Tide Forecast for Coupeville, WA

SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/
The synoptic pattern remains relatively intact, with a stationary front along the Columbia River, and a strong zonal upper level jet over the state expanding over the northern CONUS. A shallow shortwave trough will pass through Saturday afternoon, with a ridge beginning to build over the Pacific late this weekend.

Precipitation: Widespread stratiform showers continue on radar this afternoon. The precipitation has transitioned from snow to rain in spots as temperatures struggle to climb into the upper 30s this afternoon (many spots will likely remain in the mid 30s). The ensembles have the stratiform precipitation diminishing from north to south this evening. A convergence zone is expected to setup across the foothills/west slopes of the Cascades tonight into the first part of Saturday. The overall moisture output from this convergence zone will be significantly less than the precipitation past 24 hours. The temperatures tonight however will be a couple degrees cooler in spots, with lows right around freezing (areas closest to water will see lows in the mid 30s, and mountain areas with fresh snow will see lows in the teens).

For impacts: the heavy snow threat has ended for the Olympics this afternoon, and the winter storm warning was subsequently cancelled. Snow showers will continue, but are not expected to produce any significant impacts. For the Cascades, heavy snow is expected to continue on the west slopes through tonight. Travel continues to remain dangerous in the passes with several roadways experiencing closures at times today. The winter storm warning will continue into Saturday morning, with travelers encouraged to check road conditions on WSDOT before traveling.
Hi-res ensemble guidance was keeping a medium to high chance of central Cascade foothill and valley locations receiving an additional 1-2 inches of snow through Saturday morning with the convergence zone. Given the lower snow levels in this area, and the impacts from this morning's snow, the winter weather advisory was extended through 11 AM for the King/Pierce County areas, and expanded to include a portion of the foothills extending into southern Snohomish County. Snow in these areas will be dependent on the location that the convergence zone sets up. Remaining lowland areas have a low probability of seeing any accumulating snow (let alone a trace), but may still see snowflakes come down tonight for any shower that moves through.

The precipitation will wrap up Saturday evening, with a break in any moisture for the majority of the day until Sunday evening (a 30% chance of snow showers will continue in the mountains).
Temperatures will warm considerably from Friday into Saturday and Sunday, with highs returning into the mid 40s. Lows will still remain around freezing for most through the weekend. Winds will vary at times between the south and north, but generally remain around 5 to 10 mph.

LONG TERM /MONDAY THROUGH FRIDAY/
There are strong signals that the following week will continue to remain active, as ensembles continue to point to a warmer and wet pattern continuing into next week. Weak atmospheric river conditions are expected to continue as the jet stream remains on the west coast, but shifts north into northern WA/southern B.C.
next week. The main concern will be potential hydro impacts from higher snow levels from the warm air moving in, and some snow melt from recent snows. See the hydrology section below for additional details on river flooding. The precipitation is primarily focused in the mountains, and the coast. Temperatures will climb through the week, with highs approaching upper 50s to 60 towards Wednesday through Friday.

HPR

AVIATION
Stalled frontal band still giving a narrow ribbon of light snow across western WA, primarily over southern King and into Pierce counties. The trend is to still transition to a rain/snow mix then all rain moving through the rest of the afternoon and evening as the band shifts south and exits.
Showers will then reform over the central sound overnight with a weak convergence zone. Light rain or a rain/snow mix possible near the sound with snow heading east toward the Cascades.
Showers will taper off by 14-18Z as high pressure moves in. LIFR to IFR in the central sound with the snow and convergence zone, with primarily MVFR otherwise.

KSEA...Snow changing to a mix or light rain by 00Z. Models favor light rain with convergence zone overnight with higher snow levels. Surface temps remaining above freezing. Winds light and variable, switching to S to 10 kt by 09-12z. IFR improving to MVFR 15z and VFR after 18z. 33

MARINE
A stalled front near the Oregon border this afternoon will shift southeastward tonight and Saturday as a surface ridge builds into the coastal and offshore waters. This will lead to increasing onshore flow over the coastal waters and in the Strait of Juan de Fuca tonight into Saturday. The ridge will shift onshore Saturday night and Sunday as a strong warm front approaches the offshore waters. The warm front will lift northward across area waters Monday into Tuesday for increasing winds and seas.

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HYDROLOGY
Flood Watches remain in effect for SW Washington including Grays Harbor, Thurston and Lewis counties due to potential flooding. Both the Newaukum River near Chehalis and the Skookumchuck River near Bucoda have reached flood stage, with the Chehalis at Grand Mound following early Saturday.
Rivers will crest this weekend.

An atmospheric river is expected to move inland to the north early next week. This could bring additional flooding concerns to portions of the area as several rivers are forecast to reach Action Stage. For now, the only river forecast to reach flood stage is the Skokomish River.

SEW WATCHES/WARNINGS/ADVISORIES
WA...Winter Storm Warning until 5 AM PDT Saturday for Cascades of Pierce and Lewis Counties-Cascades of Snohomish and Northern King Counties-Cascades of Southern King County- Cascades of Whatcom and Skagit Counties.

Flood Watch through Sunday afternoon for Cascades of Pierce and Lewis Counties-Foothills and Valleys of Thurston and Lewis Counties-Foothills of the Western and Southern Olympic Peninsula-Grays Harbor County Coast-Lower Chehalis River Valley-Lowlands of Lewis and Southern Thurston Counties-Middle Chehalis River Valley-Olympia and Southern Puget Sound-Olympics-Willapa and Black Hills.

Winter Weather Advisory until 11 AM PDT Saturday for Foothills and Valleys of Snohomish and Northern King Counties.

Winter Weather Advisory until 11 AM PDT Saturday for Foothills and Valleys of Central King County-Foothills and Valleys of Pierce and Southern King Counties.

PZ...Small Craft Advisory from 11 PM this evening to 11 PM PDT Saturday for Central U.S. Waters Strait Of Juan De Fuca- 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-West Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory from 11 PM this evening to 3 PM PDT Saturday for East Entrance U.S. Waters Strait Of Juan De Fuca.