I surf on the Strait of Juan de Fuca, a section of water that connects the Pacific Ocean with Puget Sound near Seattle. It's an indirect link to the ocean, thus requires a funky forecast that skunks even the most experienced surfers. Once you think you've figured it out, you get skunked or you get the best session of your life but had expected nothing. Understanding surf forecasts can be very complicated but here's an attempt of explaining it, sorta, in brief..
Basic Terms -
-Period - Space between each wave crest (or wave top)
-Direction - The direction the Swell or wave is going, so West or East. Also listed as a compass direction such as 290 degrees.
-Wave Height - Height of swell (unbroken wave) coming in.
-Wind Direction - West wind means the direction the wind is coming from (or Westerly).
-Tides - Each surf spot has a specific type of wave in ideal conditions at a certain tide level. Wind direction and speed can alter that effect.
-Currents - Many surf spots are directly affected by longshore (parallel to beach) or outgoing current. Some places like the Strait list current speeds and direction. Many miss this detail.
-Wave sizing: Varies per region, some go by Waist high, overhead, double overhead.
Beach & Wave Preferences - Some beaches only break at a specific tide, wave size/direction and wind speed. And some have a variety of wave types and each person may be seeking a favorable type of wave produced by specific conditions. For example I like a high tide at a location for a certain type of wave I like but a friend prefers a barrel wave which is produced at the same location at low tides.
You'll find out what you like by going several times to a specific location. In time you figure out the personality of that beach, how wind and waves work there and the type of wave that beach produces at varying different conditons.
Wave Forecast Issues - I mentioned the funky forecasting issues we have here. Many use online forecasting tools such as Magic Seaweed, NOAA, Surfline or StormSurf. They're all good but not always 100% correct. Only NOAA lists the Strait specifically. Many think that the forecast on the sites is 100% correct - but it's a forecast which is just a prediction. Friends come home from surf trips pissed that Magic Seaweed skunked them again. Truth is, you have to use a cross section of each to get an idea whats going to happen, then make the decision if its worth driving 3 hours from Seattle. My rule of thumb is if it looks 80% good, I'll go and see what I get. But I'm easy, I can surf any size and be happy. A few friends require only overhead waves to be satisfied.
Today's forecast of the Strait varies widely per tool. NOAA says 8' west swell, 5-25kt NE wind rising to 30kt NE winds later in the day, 12 seconds. Magic Seaweed says 4' west swell, 12-15 NE winds and 12-13 sec period, 3 star. Hmm... Magic says medium winds, NOAA says gale force winds.
I know many follow Magic and similar sites because if they have rumored to have a great forecast our beaches get crowded and I see tons of cars with boards on top - and either great or no waves.
What is Big or Small? Usually I'll surf a big wave session, come home and post it on Facebook. There's usually one or two people who feel that my version of big is just a bump, or 'that's not a wave!' Ya whatever. It IS a wave. But for some big is Mavericks or Jaws. Small is 6'. Make sure you know what work for you and what your friends translate size to before you go. As a beginner go for 2-4'. Some say those aren't waves but you'll scare a beginner and they'll never go again if you insist that those are too small.
Hazards at our Beaches - As fun as surfing is it can be dangerous quick if you're not paying attention. Biggest hazards we have are offshore wind, which pushes from the beach out to sea and can push unsuspecting surfers out into bigger waves. Even breaks by little creeks can create enough outgoing current to send you to China. Watch your position - keep yourself in a little box to stay close to the beach. You can be a hazard. If new to surfing, keep a good distance from others until you can control your craft. SUPs with a leash means a roughly 20' radius around your board when you wipe out. We don't get much localism but there area few dorks at every beach who occasionally will give your some flack, usually if you're not riding their exact board size. I usually ignore or get some distance from them. Life's too short - I'm surfing today.
There's many more conditions which I can't fit here, so check out my SUP book for a whole chapter on wind, waves, beach types, surfing terminology, hazards, people issues, gear, etc. Even if you're a kayaker or traditional surfer the chapter is pretty detailed for all surfers.
Check out our SUP classes in Seattle - Beginning to advanced instruction including freighter and tug wave surfing, coastal surfing, rivers and racing, plus PSUPA Certification.