Cape Flattery to Cape Shoalwater WA between 150 and 250 NM Offshore Forecast
|Today...Sw Winds 15 To 25 Kt, Becoming W To Sw 25 To 35 Kt. Seas 8 To 13 Ft. Chance Of Rain.|
|Tonight...W To Nw Winds 25 To 35 Kt. Seas 11 To 18 Ft.|
|Wed...Nw Winds 25 To 35 Kt, Diminishing To 15 To 25 Kt. Seas 13 To 18 Ft.|
|Wed Night...N Winds 20 To 30 Kt. Seas 11 To 18 Ft.|
|Thu...N Winds 20 To 30 Kt, Becoming N To Nw 10 To 20 Kt. Seas 11 To 18 Ft.|
|Thu Night...W To Nw Winds 5 To 15 Kt, Becoming S 20 To 30 Kt. Seas 6 To 11 Ft.|
|Fri...S To Se Winds 20 To 30 Kt, Becoming Se 25 To 35 Kt. Seas 8 To 14 Ft.|
|Fri Night...E Winds 25 To 35 Kt, Becoming E To Ne 20 To 30 Kt. Seas 10 To 17 Ft.|
|Sat...N To Ne Winds 20 To 30 Kt. Seas 9 To 15 Ft.|
|Sat Night...N Winds 15 To 25 Kt. Seas 8 To 12 Ft.|
| Area Forecast Discussion|
National Weather Service Seattle WA
525am PST Tuesday Nov 29 2022
A cool but dry start to Tuesday across the region in between weather systems. However, this will quickly change as additional storm approach and move through the area bringing mountain snow and periods of rain, snow, or a mix to the lowlands. A front approaching this evening will bring gusty winds to much of the area, as well as lowland snow. Another system will bring another opportunity late Wednesday through early Thursday, with yet another system approaching by the end of the week.
Short Term - Today through Thursday
A relatively quiet morning across the region weather-wise with some higher clouds passing through as evident from satellite imagery and surface observations. Temperatures generally ranging from the mid 20s to around the freezing mark across the lowlands, with some colder readings across portions of Whatcom County as aided by the Fraser outflow. A few light snow flurries have lingered around the region early this morning from the high cloud layer, but nothing of note yet today.
That will change shortly as a convoluted weather pattern is set to unfold over the next day or so that is leading to a forecast that remains complex, uncertain, and full of potential complications.
Some key messages: *This is a very complex forecast that will continue to evolve and be fine-tuned as the weather system approaches. Continue to keep a close eye on conditions and the forecast for updates. *The transition from snow to rain will be a very fine line in many areas around the region, and it is expected that snow amounts will vary considerably across relatively short distances. *Much of the lowlands south of around Tacoma will likely see little to no snow accumulations (though some snow in the air) before switching to rain. *Areas most likely to see highest snowfall totals are the western Kitsap and Hood Canal areas, and portions of Snohomish County (particularly if stronger showers develop in a convergence zone), as well as the higher hills and into the east Puget Sound lowlands. *Winds will increase across the region this afternoon and evening, before easing early Wednesday.
The next front is beginning to approach this morning and will begin to spread some light precipitation across the region through the day. Wind will also begin to increase by the afternoon and evening hours as the front approaches. Expect south or southeast winds with gusts to 55 mph across the San Juan Islands, western Whatcom and Skagit counties, and the Admiralty Inlet Area, and gusts to 40 mph across the Everett to Tacoma corridor, including Bellevue and Seattle. Meanwhile, winds at the coast will also top out around 50 mph. These winds may be sufficient to lead to some power outages or tree limbs to fall - especially in areas that also have some heavy wet snow accumulate.
As the moisture associated with the front moves onshore, expect that precipitation will initially begin as snow for most of the area as moisture begins to run ahead of the lifting warm front. However, this is far from a classic snow setup for the lowlands as the initial dry air will preclude much initial accumulation, especially with lower precipitation rates. Additional warm advection from the southerly winds will begin to lift snow levels a bit and begin the transition to rain through the evening. It's likely that lowest elevation areas from around the South Sound down through Lewis County will only see snow in the air and little to no snow accumulation. Additionally, as this transition occurs, the rain falling on any initial accumulations will melt away the snow. For areas to the north of Seattle, it's expected that a bit more snow will be able to fall before the transition. This leaves much of the Seattle metro area more in the middle, where the confidence in how quickly the warmer air will arrive is the lowest. This is just one of the reasons for the lower confidence and larger ranges in the potential snowfall amounts.
The numerous Winter Storm Watches for the Olympics and Cascades Sound lowlands have all been upgraded to warnings. Heavy mountain snow is likely to begin over the Olympics this morning and in the Cascades later this afternoon. Accumulations on the order of 1 to 2 feet appear likely for the higher Cascade and Olympic elevations, especially on the favored slopes. A warning has also been issued for the Kitsap Peninsula and Hood Canal areas where favorable easterly flow and trapped cooler air will likely provide for more substantial snow accumulations, as well as the East Puget Sound Lowlands, though again expect there to be wide variations in totals. The remaining areas were upgraded to Winter Weather Advisories owing to the lower overall snowfall totals and the lower confidence. As previously mentioned, there is the potential for pockets of higher snowfall amounts, especially under heavy snow showers that may develop in a Puget Sound Convergence Zone behind the front late Tuesday night/early Wednesday morning.
Another round of light snow is possible Wednesday night into early Thursday as the main low drifts south offshore and begins to fill and with temperatures expected to dip well into the 20s and could bring another round of light accumulating snow. Additionally, any remaining liquid will have the potential to refreeze for early Thursday morning. Another lull in the precipitation is expected during the day Thursday, but with the next disturbance offshore there will be continued shower chances. Of course, with the cold air still firmly in place across the region, this does bring the
Long Term - Friday Through Monday
Overall, cold air is expected to remain in place across the region through early next week. With this pattern in place, there will remain the potential for any precipitation to be in the form of snow or a rain/snow mix for the lowlands. This next front around Friday or early Saturday will again bring some increased risk for a round of gusty winds and perhaps accumulating lowland snow again. Yet another impulse will bring a similar threat at the end of the weekend through around Monday, though confidence in any specific details remains quite low. Temperatures will generally remain in the 30s to around 40
A potent area of low pressure will deepen to sub-985 millibars as it approaches the north end of Vancouver Island late tonight. An associated warm front will lift northward across the coastal waters this afternoon and into the interior waters this evening. A trailing frontal occlusion will sweep onshore Wednesday morning. The surface low will gradually fill over Vancouver Island by Wednesday afternoon. Gale force winds are expected to develop with this system across the vast majority of the waters...first over the coastal waters today then spreading into interior waters late this afternoon and overnight. For a few hours this evening, wind gusts could reach 50-55 knots over the east entrance to the Strait of Juan de Fuca as well as portions of the Northern Inland waters. Additional Fraser outflow winds are possible again later Wednesday into Thursday which may require additional headlines for the Northern Inland Waters as well as the entrances to the strait. Another frontal system is expected to the reach the area on Friday.
Coastal seas of 8 to 10 ft this morning will build to 13 to 17 ft on Wednesday before subsiding Thursday into Thursday night. 27
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...High Wind Warning from 4pm this afternoon to 7am PST Wednesday for Admiralty Inlet Area-San Juan County-Western Skagit County-Western Whatcom County.
Winter Weather Advisory from 1pm this afternoon to 4pm PST Wednesday for Admiralty Inlet Area-Eastern Strait of Juan de Fuca-Everett and Vicinity-Lower Chehalis Valley Area- Western Skagit County-Western Strait of Juan De Fuca- Western Whatcom County.
Wind Advisory from 4pm this afternoon to 7am PST Wednesday for Bellevue and Vicinity-Everett and Vicinity-Seattle and Vicinity-Tacoma Area.
Winter Storm Warning from 1pm this afternoon to 4pm PST Wednesday for Bremerton and Vicinity-East Puget Sound Lowlands-Hood Canal Area-Olympics-West Slopes North Cascades and Passes-West Slopes North Central Cascades and Passes-West Slopes South Central Cascades and Passes.
Wind Advisory from 4pm this afternoon to 10am PST Wednesday for Central Coast-North Coast.
Winter Weather Advisory from 1pm this afternoon to 10am PST Wednesday for Bellevue and Vicinity-Seattle and Vicinity.
PZ...Gale Warning from 8am this morning to 2am PST Wednesday for
West Entrance USA Waters Strait Of Juan De Fuca.
Gale Warning from 10am this morning to 2am PST Wednesday for
Central U.S. Waters Strait Of Juan De Fuca-
East Entrance U.S. Waters Strait Of Juan De Fuca.
Gale Warning from noon today to 4am PST Wednesday for
Northern Inland Waters Including The San Juan Islands.
Gale Warning from 2pm this afternoon to 3am PST Wednesday for
Puget Sound and Hood Canal
Gale Warning from 8am this morning to midnight PST tonight 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.