Washington Marine Forecast

Here's link to Coastal Waters Forecast for Washington from National Weather Service in Seattle, WA. 

It's updated every few hours, as shown by the time stamp. Smart boaters check it before and during voyage. They also check the forecast for areas adjacent to where they are, for 'heads up' on possible weather changes.

The forecast is broken down by zones, such as "Puget Sound and Hood Canal". Zones are shown on map below. 

Link to WA Marine Forecast

National Weather Service - Local Forecast Areas

Use this map to know what areas NWS forecasts are refering to