Can anyone eexplain swell forecasts on MSW
I went off and it was forecast 2' but it was clearly more than that or am I reading it wrong, where is the 2' measured?
I need to make sure because of the problems I have, if its too bad then I don't stand a chance, I wish it was different because I miss being out in rougher seas, I miss the challenge, although its always a challenge :-D
Swell
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Re: Swell
by kayak-King » Sun Jul 15, 2012 11:49 am
Complicated subject I'll try my best to explain:
The swell forecast tells us the size and power of the swell coming towards us.
You are interested in two numbers.
Swell size and swell period.
It takes time to get a handle on what these numbers mean to your local break.
I go on this very rough rule to give a base to start forecasting from:
Size (ft) Period (secs) actual surf size at the beach (ft)
2 2 0
10 2 2
10 10 10
Basically you need the period to be in double figures to create a good wave as this dictates the power of the swell.
don't forget to add local winds into the equation and you get crossed eyed. My advice just go to the beach loads and keep looking at the forecasts you will start to see patterns that mean a great day out surfing...
Hopefully this is of some use. :-)
Ant
The swell forecast tells us the size and power of the swell coming towards us.
You are interested in two numbers.
Swell size and swell period.
It takes time to get a handle on what these numbers mean to your local break.
I go on this very rough rule to give a base to start forecasting from:
Size (ft) Period (secs) actual surf size at the beach (ft)
2 2 0
10 2 2
10 10 10
Basically you need the period to be in double figures to create a good wave as this dictates the power of the swell.
don't forget to add local winds into the equation and you get crossed eyed. My advice just go to the beach loads and keep looking at the forecasts you will start to see patterns that mean a great day out surfing...
Hopefully this is of some use. :-)
Ant
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kayak-King - Posts: 6
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Re: Swell
by Mike Mayberry » Mon Jul 16, 2012 9:36 am
Zec01, Ant is right in that there are two numbers you are interested in, the wave height and the swell period. The wave height is measured from the back of the wave, trough to peak and the period is the time between two peaks. They are both shown as an average.
As the wave approaches the shore it will start to "feel" the bottom causing the wave to steepen and eventually fall over itself, hence a two foot swell may produce a five foot face to surf, depending on on the topography. The greater the period then generally the distance they have travelled will have been further and the power in them will be greater, the shorter the period, the less power they will have. So a two foot swell with a fifteen second period will be more powerful than a ten foot wave with a two second period.
An offshore wind will hold the wave face up longer and an onshore breeze will make it break sooner.
Simples! :p
As the wave approaches the shore it will start to "feel" the bottom causing the wave to steepen and eventually fall over itself, hence a two foot swell may produce a five foot face to surf, depending on on the topography. The greater the period then generally the distance they have travelled will have been further and the power in them will be greater, the shorter the period, the less power they will have. So a two foot swell with a fifteen second period will be more powerful than a ten foot wave with a two second period.
An offshore wind will hold the wave face up longer and an onshore breeze will make it break sooner.
Simples! :p
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Mike Mayberry - Posts: 662
- Joined: Thu Nov 01, 2007 6:13 pm
- Location: Pembrokeshire
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