Cape Flattery to James Island WA out 10 to 60 NM Marine Forecast
|Today...Nw Wind 15 To 25 Kt Rising To 20 To 30 Kt In The Afternoon. Wind Waves 1 To 3 Ft Building To 3 To 5 Ft In The Afternoon. W Swell 13 Ft At 14 Seconds Subsiding To 11 Ft At 13 Seconds In The Afternoon. A Chance Of Showers In The Morning. A Slight Chance Of Tstms In The Afternoon.|
|Tonight...Nw Wind 10 To 20 Kt Becoming 5 To 15 Kt After Midnight. Wind Waves 1 To 3 Ft. W Swell 11 Ft At 12 Seconds Subsiding To 9 Ft At 12 Seconds After Midnight. Showers And A Slight Chance Of Tstms.|
|Fri...Nw Wind 5 To 15 Kt Becoming W To 10 Kt In The Afternoon. Wind Waves 1 To 2 Ft. W Swell 9 Ft At 11 Seconds. A Chance Of Rain.|
|Fri Night...Se Wind 5 To 15 Kt Rising To 25 To 35 Kt After Midnight. Combined Seas 7 To 9 Ft With A Dominant Period Of 11 Seconds.|
|Sat...Se Wind 30 To 40 Kt. Combined Seas 11 To 14 Ft With A Dominant Period Of 8 Seconds Building To 14 To 17 Ft With A Dominant Period Of 8 Seconds In The Afternoon.|
|Sat Night...S Wind 25 To 35 Kt Becoming Sw 15 To 25 Kt After Midnight. Combined Seas 14 To 17 Ft With A Dominant Period Of 13 Seconds.|
|Sun...Nw Wind 5 To 15 Kt. Wind Waves 1 To 2 Ft. Sw Swell 12 Ft Becoming W 9 Ft.|
|Mon...N Wind 5 To 15 Kt Becoming Ne To 10 Kt. Wind Waves 1 To 2 Ft. Sw Swell 7 Ft Subsiding To 4 Ft.|
| Area Forecast Discussion|
National Weather Service Seattle WA
856am PST Thu Dec 7 2023
A weak system traversing the region will bring lowland rain and mountain snow to western Washington today into Friday morning. A break in the weather is then expected Friday afternoon and evening before the next system moves into the region on Saturday and brings lowland rain, mountain snow, and gusty winds to the area. Another break in the weather is expected by early next week.
Precipitation associated with a rather weak weather system is falling across western WA. Snow levels are hovering between 3000-3500 feet (right around Snoqualmie Pass) and will lower this afternoon and evening. The current forecast is on track and no significant updates are needed this morning. -Wolcott-
Short Term - Today through Saturday
A weak system will continue to make its way across the area today, bringing lowland rain and mountain snow to western Washington. The system will be cooler and accompanied by lowering snow levels, with snow levels looking to drop down and hover between 2000-2500 feet by this afternoon. Showers look to continue into early Friday, with hi-res guidance indicating the likely development of a Puget Sound Convergence Zone across the central Sound. Snow amounts look to be roughly 6-8 inches for Snoqualmie Pass and near 12 inches for Stevens Pass should convergence zone banding set up within pass vicinity. Minor impacts will be possible at times across the passes, so have issued a Winter Weather Advisory for the Cascades through Friday morning. Lowland areas look to receive a couple hundredths to half an inch of rain, with a few spots expected to see half an inch to an inch. Despite the extra precipitation, do not expect the amounts to have much of an impact on area rivers - and expect to see them continue to recede throughout the day today.
Except for some lingering convergence zone activity and a few lingering showers in the Cascades, expect Friday to generally trend drier as a shortwave ridge moves into the region. The break in the wet weather will be relatively short-lived, however, as the next system moves into the area on Saturday and brings with it another round of lowland rain and mountain snow. Winds will be gusty as the system traverses the area and look to increase Saturday morning and afternoon. Gusts to 40-45 mph will be possible along the Pacific Coast and for areas from Whidbey Island northward. This system will be progressive, but will bring a round of moderate to heavy precipitation to the area - with interior lowland locations looking to receive 0.5-1 inches of rain and areas along the coast looking to receive 1.5-2.5 inches. Snow levels will be low, hovering between 1500-2000 ft on Saturday, so expect to see 8-15 inches of new snow for the Cascades.
Long Term - Sunday Through Wednesday
Precipitation looks to gradually taper Sunday with drier conditions expected Monday and Tuesday as ensembles and deterministic forecasts remain indicative of an upper level ridge building back into the region from the northeastern Pacific. Precipitation chances look to increase again near midweek, however, as the upper ridge axis starts to push inland across the interior West. This will then open the door for additional systems to move across the Pacific Northwest. 14
A compact surface low pressure system will work its way over the coastal waters this morning. Winds around the center of the low are reaching 15-25 kt and will remain elevated until tonight. Additionally, a push of westerlies through the Strait of Juan de Fuca is expected as the system moves onshore, which will develop this afternoon into early Friday morning. Therefore, Small Craft Advisories have been issued for the coastal waters and for the Strait of Juan de Fuca.
A strong low pressure system over the central Pacific will move northwestward towards Haida Gwaii into the weekend, draping a cold front over the region. Strong southerly winds reaching gale force are expected, developing late Friday night and will last through Saturday. Gusts may reach up to 50 kt for the outer coastal zone north of James Island. Gales are also likely for the East Entrance to the Strait of Juan de Fuca, the Northern Inland Waters, and Admiralty Inlet.
Seas 11 to 13 ft at 13 s will ease to around 8 to 10 ft tomorrow, before rising to around 12 to 15 ft though the weekend, reaching up to 17 ft in the windiest regions. Seas will then plummet to 3 to 5 ft into the beginning of next week. 33/LH
Area rivers continue to drop this morning across Western Washington with only the Cowlitz, Snoqualmie, and Chehalis Rivers remaining in Minor Flood Stage. These should drop back below flood stage sometime later today and into Friday for the Chehalis River at Porter.
Light rain and showers are currently moving over Western Washington this morning in association with a weak surface low and attendant cold front. This system is much weaker than the previous atmospheric river frontal system, and is not expected to noticeably impact river levels.
A slightly stronger frontal system will impact the region this weekend with more widespread lowland rain and mountain snow, though snow levels rise up above 6000 ft briefly Saturday evening into Saturday night. Total forecast rainfall amounts will be much lighter, generally ranging from half an inch to one inch in the lowlands to 2-3 inches in the Cascades and Olympics. Given the recent rain and flooding, rivers are running high and may be more responsive to the rainfall than usual. Amounts will be highest in the Olympics, so a Hydrologic Outlook was issued for Mason County concerning the Skokomish River, which may rise back into Minor Flood Stage late Saturday or Saturday night. No other rivers are forecast to return to flood stage at this time.
NOAA Seattle WA Office: Watches - Warnings - Advisories
WA...Winter Weather Advisory until 10am PST Friday for West Slopes North Cascades and Passes-West Slopes North Central Cascades and Passes-West Slopes South Central Cascades and Passes.
PZ...Small Craft Advisory until 7pm PST this evening for
Grays Harbor Bar
Small Craft Advisory until 10pm PST this evening 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-
West Entrance USA Waters Strait Of Juan De Fuca.
Small Craft Advisory until 4am PST Friday for
Central U.S. Waters Strait Of Juan De Fuca-
East Entrance U.S. Waters Strait Of Juan De Fuca.