Marine Weather Net

Cape Flattery to Cape Shoalwater WA between 60 and 150 NM Offshore Forecast


TONIGHT

WNW
WINDS
5 - 15
KNOTS

THU

N
WINDS
10 - 20
KNOTS

THU NIGHT

WNW
WINDS
5 - 15
KNOTS

FRI

SSE
WINDS
20 - 30
KNOTS

The Marine Weather Forecast In Detail:
PZZ800 Forecast Issued: 139 PM PST Wed Nov 30 2022

GALE WARNING
Tonight...W To Nw Winds 5 To 15 Kt, Becoming N To Nw. Seas 10 To 13 Ft. Chance Of Snow.
Thu...N Winds 10 To 20 Kt. Seas 9 To 15 Ft.
Thu Night...W To Nw Winds 5 To 15 Kt, Becoming S To Sw. Seas 8 To 13 Ft.
Fri...S To Se Winds 20 To 30 Kt, Becoming Se 25 To 35 Kt. Seas 5 To 9 Ft, Building To 9 To 14 Ft. Chance Of Rain.
Fri Night...E Winds 30 To 40 Kt, Becoming E To Se 20 To 30 Kt. Seas 11 To 18 Ft.
Sat...E Winds 20 To 30 Kt, Increasing To 25 To 35 Kt. Seas 12 To 16 Ft.
Sat Night...E Winds 20 To 30 Kt, Becoming E To Ne 10 To 20 Kt. Seas 9 To 16 Ft.
Sun...Ne Winds 10 To 20 Kt, Diminishing To 5 To 15 Kt. Seas 6 To 10 Ft.
Sun Night...N Winds 5 To 15 Kt, Becoming Nw 10 To 20 Kt. Seas 5 To 7 Ft.
Mon...Nw Winds 10 To 20 Kt, Diminishing To 5 To 10 Kt. Seas 5 To 7 Ft.
Mon Night...W To Nw Winds 5 To 10 Kt. Seas 5 To 6 Ft.
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Area Forecast Discussion
National Weather Service Seattle WA
425pm PST Wednesday Nov 30 2022

Synopsis
Cold conditions and lower snow levels are in the forecast as an active pattern remains into next week. Another round lowland snow is expected tonight through Thursday morning, possibly affecting the morning commute. An additional system is forecasted to traverse the area on Friday followed by more into next week.

Short Term - Tonight Through Saturday
Another interesting forecast is shaping up across the area tonight. Taking a look at the upper-levels, a positively tilted trough ushering into the PNW is tapping into an arctic airmass positioned over far northern Canada. Closer to the surface, high pressure over interior BC in concert with a developing low center offshore is slated to kick-start Fraser Outflow again this evening. Breezy to gusty conditions are likely over western Whatcom county and the San Juan Islands. Winds combined with cold temperatures in place will set the stage for well-below freezing wind chill values anywhere between 0 to 15 F for these locations. Impacts are likely after midnight into Thursday morning. Additionally, post-frontal showers are likely across western Washington for the remainder of the evening. Snow has been reported in heavier precipitation so can't rule out additional bouts. More snow is possible overnight into Thursday morning as the aforementioned developing surface low tracks near the Columbia River. Wrap around precipitation associated with this feature looks to track into the CWA (County Warning Area) during this time. Model derived soundings are indicative of a fairly saturated dendritic growth zone and an atmospheric column at or below freezing towards the surface over much of the area is further increasing confidence. Because of this, a Winter Weather Advisory is in effect over most of the CWA except for the Northern Interior where precipitation is not expected to enter. Snowfall amounts up to 1 to 3 inches are possible over the lowlands with 5 to 8 inches over the mountains and higher elevations into the first half of Thursday. This can very well bring impacts to the morning commute. Areas that won't receive snow may still see potential impacts as any lingering moisture on untreated roads is likely to freeze with cold temps in place.

A brief break in the action is likely to set up as Thursday progresses. A transient ridge looks to pass over and remain into early Friday allowing the return of drier weather but well-below temperatures are to remain. However, conditions are on tap to deteriorate again as another shot of widespread rain and snow potential appears to be looming. To note, confidence is not high as many variables appears to be in place. But, we'll see below freezing temperatures at the start of the day before conditions warm up by way of a warm frontal passage. An event similar to Tuesday is possible as the warm front looks to over-run cold air at the surface, bringing precipitation that could start off as snow then an eventual transition to rain for some lowland locations. More details will be provided in further updates on how this system is expected to evolve.

Looking ahead, the general trend for Saturday is that it will remain somewhat unsettled and chilly as an upper-level low is forecasted to churn over the coastal waters. Conditions are to be drier in comparison to Friday but can't rule out lingering scattered shower activity.

Long Term - Sunday Through Wednesday
A brief dry period expected on Sunday as any chance for precipitation appears to be well off to the south of the CWA. But, it won't be too long before the next system begins to move in on Monday with another chance for lowland snow for the start of next week. Temperatures will remain near 40 during the day and near freezing during the overnight.

McMillian

Marine
A low pressure system just offshore will start to track southward through the evening. with strong southwest flow aloft. Small craft advisories are out for all area waters except for Puget Sound, Hood Canal, and Admiralty Inlet for this afternoon. A surface high pressure over British Columbia will move southward later this evening, helping gusty Fraser Outflow winds expand into adjacent waters. Therefore, have upgraded the Gale Watch to a Gale Warning for the Northern Interior Waters. Have also included a Small Craft Advisory for Admiralty Inlet, and have extended existing Small Craft Advisories elsewhere until Thursday morning.

A brief lull in the winds expected throughout the day on Thursday before another frontal system arrives on Friday which will likely bringing another round of headlines - potentially widespread gales over coastal waters.

Coastal seas hovering around 10 to 12 feet per recent observations, and will gradually subside to just around 10 feet through Thursday. Seas will build back up into the 11 to 12 feet range with the other system on Friday.

Mazurkiewicz

Hydrology
There will be active weather this week with significant amounts of precipitation, but snow levels will be low. Rivers will rise, especially the Skokomish, but there will not likely be enough storm runoff for river flooding due to the snowfall over much of the area.

NOAA Seattle WA Office: Watches - Warnings - Advisories
WA...Winter Weather Advisory until 4pm PST Thursday for Admiralty Inlet Area-Bellevue and Vicinity-Bremerton and Vicinity- Central Coast-East Puget Sound Lowlands-Eastern Strait of Juan de Fuca-Everett and Vicinity-Hood Canal Area-Lower Chehalis Valley Area-Olympics-Seattle and Vicinity- Southwest Interior-Tacoma Area-West Slopes North Central Cascades and Passes-West Slopes South Central Cascades and Passes-Western Strait of Juan De Fuca.

PZ...Small Craft Advisory until midnight PST tonight for
Grays Harbor Bar

Small Craft Advisory until 7am PST Thursday 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-
East Entrance U.S. Waters Strait Of Juan De Fuca-
West Entrance USA Waters Strait Of Juan De Fuca.

Small Craft Advisory until 10pm PST this evening for
Northern Inland Waters Including The San Juan Islands.

Gale Warning from 10pm this evening to noon PST Thursday for
Northern Inland Waters Including The San Juan Islands.

Small Craft Advisory from 4am to 9am PST Thursday for Admiralty Inlet.