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Bit confused I am. Not for the first time but still ....
I just can't relate your forecasts to anything that I would actually expect to see at the beach. For example this Saturday Fresh West has a forecast wave period of 7 to 8secs .... and Llangennith has 8 to 10secs. Is this an average wave period forecast or peak ? Surely, given an almost W swell direction these 2 beaches would receive the same period ? OK the height may vary between the two due to shallow water effects etc but the period remains the same... ? Am I wrong?
Last Sunday and this Saturday are very similar from the ouput from the WW3 models and I'm expecting similar waves (although we've got strong offshores forecast this weekend so that may dampen the swell slightly).. but looking at your forecasts this weekend should be resigned the scrap heap. Perhaps it is a tactic to keep the crowds away? If so, I like your thinking.
Anyway ...what do you think? I can see from reading other notes that you don't just rely on models to form the forecast so ....?
This isn't a stab at dodgey forecasts, I'm just trying to understand your methodology and expand my teeny brain.
ta

Wave and Swell Period

Hi Jeff - sorry it's taken me a while to get back to you. I hope this helps:

Wave and Swell Period

The swell period forecasts on the site are the average of the swell period at that time. What I have to explain more clearly is that there are two types of period that are measured wave and swell. The difference between wave and swell is that the wave is considered to be the local wind sea state and the swell is considered the complete underlying sea state.

I do receive 'wave' data but choose not to display it as for many people it would be to confusing. This is a little more complicated - but the way wave and swell is separated is by the wave period, with a cutoff between what is classified as swell or wind waves. The cut off point in the Met Office model is any data with a period greater than 6 seconds, is swell rather than waves.

The point I'm trying to make is that for the forecasts that we're talking about ( Freshwater 29th March & Llangenith 29th March ) are marginal in that they show periods of 7 or 8 seconds with very small actual swell height. Non of the models available are perfect and the forecasts on this site are focused towards good surfing conditions, so when it's touch and go whether there's going to be a good waist height wave and a soft knee height wave - you still have to take a bit of a gamble.

As for the differences between Freshwater and Llangennith we do just rely on the models for the forecasts but the Llangenith may have been showing a larger period as it further down the coast, the waves take longer to get there, therefore increasing the period.

Wave Quality Rating

The way the quality of the waves are rated takes a lot of these factors into consideration. By choosing the rating that's more suited for your level of surfing you can quickly work out which days are worth having a look at.

The idea is that beginners get valuable surfing time from a wider variety of conditions - if it's 2 foot and onshore it's still good for a beginner, to build up paddle strength and will get 2 stars where as an experienced surfer wants bigger cleaner waves with more punch - so 2ft onshore will only get 1 star.

On the other end of the scale, if it's perfect and large at 5/6 foot the experienced rating will be 5 stars, but a beginner my feel uncomfortable in waves that big so that rating will drop to 3 stars for them.

In order to calculate these ratings the system considers the swell/wave period/height, the wind direction/strength, the angle of the break and the type of break (beach, reef, point, river mouth).

Anyway I hope that makes sense, let me know if it doesn't and I'll try to improve the explanation - a lot of people must be confused by it.

sam@surfcore

Hi Sam, thanks for the

Hi Sam, thanks for the reply.....

"As for the differences between Freshwater and Llangennith we do just rely on the models for the forecasts but the Llangenith may have been showing a larger period as it further down the coast, the waves take longer to get there, therefore increasing the period"

Wouldn't mind getting my hands on the wave model that shows the wave period in this much detail. Does this nearshore model of yours do this ? Any chance of getting a look at it?

cheers
jamie

Sorry I haven't got back

Sorry I haven't got back to you. I've been waiting for an article that Tony Butt has written about the Surfcore forecasting system to come out in Surfers Path, which explains all of this in more detail. We're well excited it's out now on page 30-36.

Will post the relavent section of the article tomorrow...