thermalben, 1571700660
Looking pretty serious in the Margs region already, and this swell isn't expected to peak until tomorrow (and then another bigger one Thurs!).
[img]https://imgur.com/QjbXXy0.jpg[/img]
[img]https://imgur.com/MT5o1WA.jpg[/img]
[img]https://imgur.com/witOZ0H.jpg[/img]
thermalben, 1571701269
Got one with a size reference.
[img]https://imgur.com/xQ7lmDS.jpg[/img]
thermalben, 1571706571
One bloke out at Yalls and he's just about to cop this on the head.
[img]https://imgur.com/ZVTXD0K.jpg[/img]
thermalben, 1571706775
Shit! Old mate just copped another three waves on the head, literally less than a minute after the one above. Here's the first wave of the set about to smash 'im. Perverse pleasure watching someone get hammered in real time from the other side of the continent.
[img]https://imgur.com/rAINnua.jpg[/img]
[img]https://imgur.com/syiDdra.jpg[/img]
Bnkref, 1571706931
That is cooking!
Careful, Ben. Huey will remember that!
Yals cam has got to be one of the best ones to watch when it's on.
velocityjohnno, 1571713906
It hits you a lot harder when it does that compared to east coast Ben, but you'd know that growing up in SA with its West Coast.
Have been in exact same spot as old mate in pics, I got 7 on the head. Not fun.
trevbucky, 1571738196
Wow! That’s solid Yall’s!
trevbucky, 1571738272
Hey Ben you said “ WA’s buoy network isn’t ideal to monitor swell conditions (because the way the data is presented is different to convention)“
Can you explain this, as over the years I’ve found the buoy readings very accurate?
thermalben, 1571739105
The time series graphs don’t display conventional data such as Tp, Tsig, Hmax, Hsig.
Instead, it shows ‘significant wave heights’ and ‘mean swell periods’ for two parameters each: ‘swell’ and ‘sea’.
So, it’s hard to compare apples with apples. There was no way to know when the leading edge of today’s swell arrived.
The highest swell period at Cape Nat in the last day or so was 14 seconds, when it should have been 18-19. Watch the SA, Vic and Tas buoys record Tp values of that magnitude once the leading edge of the same swell reaches there tomorrow.
goofyfoot, 1571739782
How’s the left off it!
t-diddy, 1571797927
I did not envy that guy; that is solid
velocityjohnno, 1571798184
Usually it's a fatter wall but that is cracking!
thermalben, 1571802161
Here ya go Trev.
Buoy data from Cape Naturaliste for the last couple of days. Highest recorded swell period is 14 seconds.
[img]https://imgur.com/gJBnKZV.png[/img]
The same swell that produced 10ft+ surf yesterday has just reached the Cape du Couedic wave buoy in South Oz, and peak swell periods are now 18 seconds (in fact, without wanting to confuse the issue further, the CdC buoy actually detected 19-20 second periods several hours ago but it wasn't the dominant swell train and thus didn't register as the "peak period").
[img]https://imgur.com/ujtJfkZ.png[/img]
Jamyardy, 1571803243
Good point Ben, For Naturaliste you need to look at the Sea and Swell Directional graph (the top graph in their website). The Swell period here is almost always a few seconds higher than that shown on the Significant Wave height Graph (the one Ben has above). I guess the directional graph shows period for the significant wave heights as opposed to mean period for the swell (all waves with period above 8s) in the Significant Wave height graph, but that's just a guess. The Naturaliste buoy did show readings of 18s period yesterday on the directional graph, but you won't see that on the historical timeline graph.
thermalben, 1571803980
Yeah I know it has those period values on the other chart (Camel's pointed it out many times) but isn't available in the time series graph.. so it is somewhat pointless.
Also, the way Swell' waves and 'Sea' waves are calculated is not known. In most cases the spectra is usually truncated at some point (say, 11 seconds) but the 'mean period' of 'swell waves' and the 'mean period' of 'sea waves' (as well as the 'mean period' of 'total waves') is very confusing.
Let alone the 'significant wave height' of 'swell waves', the 'significant wave height' of 'sea waves', and the 'significant wave height' of 'total waves'.
Hsig (significant wave height) is a standard oceanographic measurement - the average height of the highest 1/3 of all waves. What the DPI charts are suggesting is that the ocean state is split into sea waves and swell waves (say, above/below 11 seconds), and then the "average height of the highest 1/3 of all waves" is calculated upon that split for each data set.
Main reason it's annoying is that it's hard to validate model data. Every other state/national/international agency with deployed buoys uses standard conventions.
Jamyardy, 1571805735
I can't speak for others, but the history is just that, history. I do see how its important to you as you forecast and probably like to hindcast that forecast etc. When I check the buoy, its usually before the surf and after the surf so I can reference wave size etc in the water against what the buoy was showing, so I look at the directional graph which is pretty much real time and on point for me, so next surf I am better equipped to know what I will be getting.
I am pretty sure WA uses 8s to differentiate between Sea and Swell. At the bottom of the below linked page you can see how BoM references both 11s and 8s to differentiate between swell types.
http://www.bom.gov.au/marine/knowledge-centre/reference/waves.shtml
My theory is that the Freo doc is so regular, that they don't want those "wind" waves intruding (graphically speaking) with the actually swell(s) coming in, so they break them out …. but who knows for sure. WA measures Hs(m), Tp(s), T1(s), and Dir(deg) for both sea and swell on their buoys.
Edit : In addition the time series graph doesn't show direction, and that's a very important factor in the SW, another reason why the directional graph does it for me.
thermalben, 1571806080
Actually, they can filter out wind waves effectively using Tsig (significant swell period).
FWIW, the Qld buoys (run by the Dept Environment) displays Tp (peak swell periods) and Tz (zero crossing period).
[img]https://imgur.com/JPhQwtz.png[/img]
Tz is less useful for surfing, because it is the average period of ALL waves - and therefore is easily contaminated by afternoon sea breeze etc.
In contrast, Tsig (significant swell period) is the average period of Hsig waves... i.e. the average period of the average height of the highest 1/3 of all waves. Tsig equates very strongly with broader 'surf' trends (especially when used in conjunction with Tp, to detect leading edges).
thermalben, 1571806230
Also, the WA wave buoys - like every other directional buoy - record everything (i.e. spectra).
It's the output display that's different.
thermalben, 1571808919
Bit of a mess, but still pretty big.
[img]https://imgur.com/yfxwrTV.jpg[/img]
Jamyardy, 1571809555
Thanks Ben, its always good to learn something new. In the WA Significant wave height graph (time series you refer to), would the blue line in the period section be the Tz, as it refers to total, I assume all waves ? Yeah WA does display differently, its a pity there is not a standard across the country (I don't look at other states buoys as I am rarely in them, maybe all the other states display the same info)
thermalben, 1571810144
Yeah, I'd assume them to be the same (arithmetic mean = average).
Unfortunately, it's the least useful period measurement to be calculated.
trevbucky, 1571996781
Thanks heaps for the amazing info Ben, I had to read it a few times, and I’ve learnt a few new acronyms now!
I work at Department of Transport Wa so I’ll feed your comments back to the boys in Coastal Data and see what they say! Cheers...
nicko74, 1572000496
Sunday is looking very thick