Forecast question
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Means nothing zeta , zilch absolutely zilch, always changes every day, day to day.
The only real wave heights you're gonna get are the one you experience in the water surfing;)
If forcast says 5m @ 13 & your nearest swell buoy ( real time ) is the same then alls perfect ? Right
Not necessarily Caml. Depends on what data you're looking at (both forecast and observation). Which location are you referring to? The Margs forecast and the Naturaliste buoy?
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Gday zeta...... What exactly don't you get?
Zeta, the model forecasts are for deepwater swell trains.
However the live buoy observations - whilst also for deepwater swells - are for Significant wave heights and Maximum wave heights (which we don't plot). Instead, we plot individual swell trains (which is more accurate for surf forecasting).
Nevertheless, there is a reaosnably good correlation between the Cape Sorell buoy and our Cape Sorell forecast: https://www.swellnet.com/reports/australia/tasmania/cape-sorell/forecast
As you can see from the forecast below, the primary swell (which is the only swell train modeled to be in the water) is expected to be somewhere between 7.0m (6am) and 5.5m (6pm).
This roughly equates with today's Significant wave height observations from Cape Sorell (blue line).
The red line is maximum wave height, which we don't calculate in our forecasts because it's not as useful for surf forecasting.
Where things come unstuck (re: buoy data vs model forecasts) is in the period measurements.
Most buoy software programs don't calculate individual swell periods by default.. they just display Average periods (also known as Zero Crossing), or Significant periods (the average period of the highest 1/3 of all waves), plus Maximum Period. These are different to the swell periods of individual swell trains.
Sometimes they'll match up (ie leading edges with Tmax, and strong solitary swell sources) but as soon as there's a number of swells in the water - for example, when there's a lot of windswell - the Significant period values can become 'contaminated'.
Not sure if that explains things a little better for you?
Cheers, Ben.... There you go, zeta...... I don't use wavewatch3.... I just go by the charts like the one you supplied in your 10.10am post.... I'm just an old school basic sort of forecaster....
You do know how to interpret those charts? as in Hmax etc? That's about all I could help you with....
Oh and using ascat and calculating swell size and arrival.....
Settle
Hi Guys,
I have a question about the wave heights displayed in the forecast. If it says 5m swell at 13s, are we talking significant wave height? If so, is it calculated the same way as in WaveWatchIII with H_s = 4 sqrt(E)?
I am trying to gauge if a certain swell is behaves as predicted compared with realtime buoy measurements.
Also, if it says lets say 4ft, does that mean 4ft on the sets or on average?
Thanks alot,
Cheers