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  1. #1

    long period swells coming

    Models are calling up to 16 sec period waves for wednesday. I thought we only saw those kinds of periods from southern hemi swells or hurricanes. Looks like the waves are coming from a low that is going to build in the north atlantic over the next few days, but we see normally SW-SE wind swell from these lows. What gives? Swellinfo, im thinking you can give a good explination. Also how bad will the continental shelf hurt a swell at this long of a period?

    I'm thinking high tide by an inlet is the way to go on this one.

  2. #2
    it seems just about anywhere in sc can't accept a swell any longer than 10-12 secs. i've seen some chart explaining the ocean depth to swell dissapation before and if i recall a 16 sec period would require something like 150 feet in depth to not lose energy. (whtever it was it was deeper than our shelf). your probably right with the inlet at high tide call. sometimes swells creep in the deeper inlet channels and stands up a little steeper when they do break. not used to seeing them this time of year for sure. it should be interesting to see what turns up.

  3. #3
    it seems just about anywhere in sc can't accept a swell any longer than 10-12 secs. i've seen some chart explaining the ocean depth to swell dissapation before and if i recall a 16 sec period would require something like 150 feet in depth to not lose energy.
    What do you mean can't accept? Anyone know how deep does the continental shelf gets around here?

  4. #4
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    Quote Originally Posted by dirtyhairy130 View Post
    Models are calling up to 16 sec period waves for wednesday. I thought we only saw those kinds of periods from southern hemi swells or hurricanes. Looks like the waves are coming from a low that is going to build in the north atlantic over the next few days, but we see normally SW-SE wind swell from these lows. What gives? Swellinfo, im thinking you can give a good explination. Also how bad will the continental shelf hurt a swell at this long of a period?

    I'm thinking high tide by an inlet is the way to go on this one.
    looks looks models have this low blowing up in the central waters, apparently with good enough circulation to send some E ground swell back our way. 16 second periods is very long for this type of system (not really that far away from the coast), so models are really calling this storm to blow up. This storm hasn't developed yet, so you'll have to keep an eye on the forecasts from update to update here.

    As far as long period swells, the longer the period the the deeper the water the wave energy reaches down. So, many places along the east coast have a hard time dealing with the long period swell, because some of the energy can be absorbed offshore and also the sandbars generally cant handle the long period swells.

    Your remark about high tide is generally a good one with the longer period swells. The higher water level means less chance for the wave energy to be absorbed offshore.