James Island to Point Grenville WA out 10 NM Marine Forecast
|Tonight...Se Wind 5 To 15 Kt Rising To 15 To 25 Kt After Midnight. Wind Waves 1 To 2 Ft Building To 3 To 5 Ft After Midnight. W Swell 8 Ft At 11 Seconds. A Chance Of Rain After Midnight.|
|Sat...Se Wind 25 To 35 Kt Rising To 30 To 40 Kt In The Afternoon. Combined Seas 6 To 9 Ft With A Dominant Period Of 10 Seconds. Rain.|
|Sat Night...S Wind 20 To 30 Kt Easing To 15 To 25 Kt After Midnight. Wind Waves 4 To 6 Ft Subsiding To 2 To 4 Ft After Midnight. Sw Swell 15 Ft At 13 Seconds. Rain.|
|Sun...Sw Wind 5 To 15 Kt Becoming To 10 Kt In The Afternoon. Wind Waves 1 To 2 Ft. Sw Swell 12 Ft At 12 Seconds.|
|Sun Night...W Wind To 10 Kt. Wind Waves 1 To 2 Ft. Sw Swell 9 Ft At 12 Seconds.|
|Mon...N Wind To 10 Kt. Wind Waves 1 To 2 Ft. Sw Swell 6 Ft At 11 Seconds.|
|Mon Night...E Wind To 10 Kt. Wind Waves 1 To 2 Ft. W Swell 4 Ft At 10 Seconds.|
|Tue...E Wind 5 To 15 Kt. Wind Waves 1 To 2 Ft. W Swell 2 Ft.|
|Wed...Se Wind 5 To 15 Kt. Wind Waves 1 To 3 Ft. Sw Swell 3 Ft Building To W.|
| Area Forecast Discussion|
National Weather Service Seattle WA
312pm PST Fri Dec 8 2023
The next vigorous system will move into the region Saturday into Sunday and will bring moderate to heavy rain, mountain snow, and areas of gusty winds. A quieter period of weather is expected early next week as upper level ridging moves back into the region.
Short Term - Tonight Through Monday
Weak convergence is ongoing in the central sound and Cascades where showers remain. Additional, significant snowfall is not expected in the mountains and the Winter Weather Advisory has now expired. Onshore flow will weaken and turn offshore tonight as we prepare for the next incoming system. But with the flow turning offshore we will see cooler overnight lows in the 30s for most spots, with a few areas near freezing.
The forecast remains active this weekend as a strong Pacific frontal system moves in. This system brings another round of heavy rain and mountain snow and also strong south wind (mainly north coast and areas north of Whidbey Island). For the rain, we're expecting another 0.50-1.00" north of Seattle, 1-1.50" south of Seattle and 1-3" along the coast. The mountains will see a rain/snow mix but heavy accumulations may force sharp rises on the rivers once again with many rivers (Snohomish south) rising back into action stage to near minor flood. Up in the mountains, it'll be a wintery mix with snow Saturday afternoon/evening turning over to rain Sunday morning. Easterly winds may keep snow levels low in the passes with freezing rain possible at both Snoqualmie and Stevens pass Sunday morning. As for the winds, strongest south winds will be along the north coast, Admiralty Inlet area and San Juans - a Wind Advisory is in effect.
The frontal band will shift to our south on Sunday but we will still continue to see light rain across much of the area. Weak high pressure shifts inland on Monday but we're still left with abundant low level moisture and light sprinkles. The air mass will be mild, though, with temps in the 40s and 50s. 33
Long Term - Tuesday Through Friday
High pressure continues to build over the Pac NW early next week for a break in the weather. A weak system may sneak inland toward midweek but overall rainfall amounts are light with just a few hundredths across the board. High pressure then rebuilds for the latter half of the week for another respite. Lows will be cooler and in the 30s with highs in the 40s moving into next weekend. 33
A strong low pressure system is moving into the NE Pacific for the weekend, draping a cold front over the area waters. The forecast remains on track for strong southerly winds reaching gale force beginning late tonight through Saturday for the coastal waters. Gales are also likely Saturday for the East Entrance to the Strait of Juan de Fuca and Admiralty Inlet. Therefore, Gale Watches have been issued for the aforementioned locations. Winds will likely reach gale force into the Haro Strait, but have held off issuing a gale watch for the entire Northern Inland Waters zone. Winds will taper off Saturday night and remain benign into next week.
Benign conditions tonight but a sub-990 mb surface low will track just north of Haida Gwaii Saturday morning as its associated cold front swipes across area waters throughout the day. Gales are in the forecast over the coastal waters, eastern section of Strait of Juan de Fuca and the Northern Inland waters with SCA (Small Craft Advisory) winds a possibility over Puget Sound. Winds will taper off Saturday night and remain below headline criteria into the beginning of next week.
Seas 7 to 9 ft tonight before rising to around 12 to 16 ft though the weekend where SCA (Small Craft Advisory) for hazardous seas may be needed after winds subside. Seas will then decrease to 3 to 5 ft by Monday-Tuesday before the next system brings seas back above 10 ft by Thursday.
The Chehalis River at Porter remains in Minor Flood and is the last flood warning still in effect.
A brief lull in activity continues tonight before the next frontal system brings another round of rain and mountain snow. Snow levels start off between 1500 and 2000 ft Saturday then rise to near 7500 ft Saturday night. Forecast rainfall totals came in a little lower again today with mountain locations ranging from 2 to 3 inches with isolated higher amounts.
Antecedant conditions of high soil moisture and high river levels are favorable for new flooding. The forecast amount of rain with higher snow level will drive significant river rises in a few locations but for most areas it will result in flooding. The most likely river to flood is the Skokomish where a flood watch is out for Mason County. There is a low chance of flooding in additional areas, mainly for the Snoqualmie River and the Chehalis River Basin. There is a Flood Potential Outlook for those areas, for King, Thurston, Lewis, and Grays Harbor Counties.
NOAA Seattle WA Office: Watches - Warnings - Advisories
WA...Wind Advisory from 9am to 9pm PST Saturday for Admiralty Inlet Area-San Juan County.
Flood Watch through Sunday morning for Hood Canal Area-Lower Chehalis Valley Area-Olympics.
Wind Advisory from 7am to 6pm PST Saturday for North Coast.
Winter Weather Advisory from 10am Saturday to 4am PST Sunday for West Slopes North Cascades and Passes-West Slopes South Central Cascades and Passes.
Winter Storm Warning from 10am Saturday to 10am PST Sunday for West Slopes North Central Cascades and Passes.
PZ...Gale Warning from 6am to 11pm PST Saturday for
East Entrance U.S. Waters Strait Of Juan De Fuca.
Gale Warning from 8am to 10pm PST Saturday for
Northern Inland Waters Including The San Juan Islands.
Gale Warning from 1am to 7pm PST Saturday 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.