
I'm not sure what this website's model is preceisely trying to forecast, but a lot of the swell models predict "significant wave height" which is defined as:
"In physical oceanography, the significant wave height (SWH or Hs) is defined traditionally as the mean wave height (trough to crest) of the average of the highest third of the waves (H1/3)"
If you think about it, if a set of overhead waves comes through every few minutes, think about the vast number of waist high, chest high, and other waves coming in. If significant wave height is what's being forecast, then a forecast of shoulder high is completely consistent with overhead sets, if there are also a lot of chest high and smaller waves mixed in.
All swells are reported in significant wave height for each individual swell. Significant wave height is calculated as 4*sqrt(E), where E is the sum total of wave energy. For surf forecasting, you wouldnt want to take the significant wave height of the entire wave spectrum, because you may have multiple concurrent swells of different directions and frequencies (periods). This is why the significant buoy readings can be misleading when there are multiple swells in the water. So, it is important to sort out the individual swells through statistical methods.
PS. If you look at the new Swell Timeline (click on the "Swell button"), we now show the Overall significant wave height in the gray line.
Well I got skunked!!!! Sat at work, seeing super fun Chest to Shoulder high clean swell coing in all morning in VB. I got off work a little later than I wanted to and got to the beach at 5. Tide dead low, SE winds all over it, dumpy stomach high closeouts on the sand bar. Absolutely crap. I surfed from 5 til 630 trying to scratch out a decent wave, found nothing compared to what was going on all day while i was at work, skunked!
Got on it early at Pendleton. Then the MP's ran us off, parking lot closed all week, it was dumpier more north of the fence. They picked a hell of a week to lock the lot, first time I've seen it closed this long. At least I got a couple....