San Juan Islands and Northern Inland Waters Marine Forecast
| Tonight...Sw Wind 5 To 10 Kt, Veering To W After Midnight. Waves Around 2 Ft Or Less. A Chance Of Showers This Evening. A Slight Chance Of Tstms. Rain Likely After Midnight. |
| Sat...Sw Wind 5 To 10 Kt. Waves Around 2 Ft Or Less. A Chance Of Rain In The Morning. |
| Sat Night...S Wind 5 To 10 Kt. Waves Around 2 Ft Or Less. |
| Sun...S Wind 5 To 10 Kt. Waves Around 2 Ft Or Less. |
| Sun Night...S Wind Around 5 Kt, Backing To E After Midnight. Waves Around 2 Ft Or Less. |
| Mon...Ne Wind Around 5 Kt, Backing To W In The Afternoon. Waves Around 2 Ft Or Less. |
| Mon Night...W Wind Around 5 Kt, Backing To S After Midnight. Waves Around 2 Ft Or Less. |
| Tue...S Wind Around 5 Kt, Rising To 5 To 10 Kt In The Afternoon. Waves Around 2 Ft Or Less. |
| Tue Night...Sw Wind 5 To 10 Kt, Becoming S 15 To 20 Kt After Midnight. Waves Around 2 Ft Or Less. A Chance Of Rain In The Evening, Then Rain Likely After Midnight. |
| Wed...Se Wind 20 To 25 Kt. Waves 3 To 4 Ft. Rain Likely. |
| Wed Night...Se Wind 15 To 20 Kt, Becoming S 10 To 15 Kt After Midnight. Waves 3 To 4 Ft In The Evening, Then Around 2 Ft Or Less. Rain Likely, Mainly In The Evening. Winds And Waves Higher In And Near Tstms. |
| Area Forecast Discussion National Weather Service Seattle WA 746pm PDT Fri August 28 2026 Synopsis An upper-trough will swing another weather system into the region tonight into Saturday. Brief ridging is expected to begin next week but an active pattern is forecast to return by Tuesday as additional troughing sets up. A well-ogranized system looks to arrive around midweek with the potential for widespread rainfall. Cooler than average temperatures are favored throughout this time. Short Term - Tonight Through Sunday Night Latest radar showing some weak echoes off the NW tip of the Olympic Peninsula this evening lining up with the weak front models will push into the area tonight and Saturday morning. Also present could be the very beginning of the expected PSCZ over the southern islands and only just now starting to creep into western portions of Skagit and Snohomish counties. This activity is good indication that inherited forecast is on track with no need for evening updates. For additional forecast details, please refer to the Previous Discussion section below. 18 From Previous Discussion...We're in between systems here across western Washington as the next disturbance looms off the BC coast. Conditions are mostly dry but that'll change later tonight into early Saturday morning. A convergence zone is slated to develop this evening, mainly Snohomish County northward before meandering southward into Saturday. The aforementioned upper-low will also track across the area during this time as rain showers become widespread. Overnight lows will range throughout the 50s with a few spots in the upper 40s. Active weather into Saturday as the upper-low not only bring showers but the potential for thunderstorms. HREF has 200-400 j/kg of surface based CAPE analyzed across western Washington Saturday afternoon. Mean 700-500 mb lapse rates are also around 7 C/km, indicative of some degree of instability. These parameters in place with dynamics provided by the upper-low has allowed for parts of the CWA (County Warning Area) to placed in the SPC's convective outlook for general thunderstorms. The threat will end Saturday night as an upper-level ridge enters the fray with conditions drying out. Can't rule out areas of fog developing into Sunday morning with lingering surface moisture and lighter winds. Ridge axis is modeled to pass directly overhead on Sunday as morning clouds give way to mostly clear skies in the afternoon. However, the flow aloft will trend more out of the southwest on Sunday night as the next upper-low digs over the NE PAC. High temperatures in the 60s to lower 70s throughout the short term with overnight lows in the mid 40s to lower 50s. Long Term - Monday Through Friday Conditions will remain drier on Monday as the upper-ridge exits the region. Then, the next upper-trough will continue to dig over the NE PAC and sit right off the PNW coast by Monday evening. Given latest guidance, it's associated upper-low will track south of the area into Oregon but we could get side swiped with showers on Tuesday. Then, a more organized disturbance is slated to arrive Wednesday and possibly stalling over the region into Friday. This feature has the potential to bring widespread rainfall and well-below average temperatures as the region will begin to get a taste of fall with highs only in the 60s. Marine A weak frontal system will move through the area waters tonight, which will maintain northwesterly winds through the coastal waters through Saturday, as well as bring pushes of westerlies down the Strait of Juan de Fuca tonight and Saturday night as well. A Small Craft Advisory is in effect for the Strait tonight, and another will likely be needed tomorrow. Systems will pass by well to the north on Sunday and Monday, keeping winds fairly light across the area. A stronger low pressure system look to move through the area waters Tuesday into the middle of next week, which may bring increased winds to much of the coastal waters and higher seas through the middle of next week. Seas remain 4 to 6 ft through Tuesday, then increasing to around 7 to 9 ft by the middle of next week. 62 Fire Weather Onshore flow, cooler temperatures, and increasing RHs will persist through next week. An upper level low pressure system will bring chances for showers this evening through Saturday evening. In addition, there still remains an isolated threat for thunderstorms Saturday afternoon mainly over the Northern and Central Cascades. If a thunderstorm develops, wetting rains are unlikely and lightning may pose a hazard that could lead to new fire starts. Erratic and gusty outflow winds over existing fires could also be problematic. Weather system next Wednesday has a good chance of producing wetting NOAA Seattle WA Office: Watches - Warnings - Advisories WA...None. PZ...Small Craft Advisory until midnight PDT tonight for Central U.S. Waters Strait Of Juan De Fuca- East Entrance U.S. Waters Strait Of Juan De Fuca. |
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