Swell height vs. wave height

Discussion in 'Weather and Surf Forecasting' started by clintopher, Aug 12, 2012.

  1. sisurfdogg

    sisurfdogg Well-Known Member

    Jun 17, 2013
    Aug 12, 2012#3
    [​IMG]
    SwellinfoAdministrator
    5,504
    May 19, 2006
    The significant wave is roughly the wave height of the top 30 percent of all waves.
    The swell height on the buoy maps refers to the primary swell at the buoy location.

    With statistical approaches we can segregate wave magnitude, frequency, and direction at the buoy location into individual swell groups.

    Both significant wave height and primary swell height are telling in the breaking wave. As are secondary and tertiary swells. This intricate nature of the wave spectrum is one of the trickiest part of forecasting. You have to think of waves in terms of an entire 360 degree spectrum.

    Primary swell is usually the most telling, but additional swells can combine to become additive to the total breaking wave height.

    Some examples:
    Significant wave height: 5ft
    Primary swell: 3ft @ 12 seconds, ESE
    Secondary swell: 5ft @ 6 seconds, NW

    If this is an east facing break, the secondary swell is actually moving away from the coast, do the primary swell will be most telling.

    Significant wave height: 5ft
    Primary swell: 3ft @ 12 seconds, ESE
    Secondary swell: 4ft @ 9 seconds, SSE

    In this example the primary and secondary swells are additive to create a bigger overall significant wave height.

    So when are you going to get your shit together and give me a decent forecast againne you total kookster?