I don't know, but IME the wave heights reported by NOAA aren't very
accurate either. I don't really know how wave heights can be
accurately measured.

I'm not sure how they do the waves from the buoys, but there aren't
that many of those.

Bouys, satellites, ship obsevations....





As far as weather forecasts go - more than once the forecast has been
15-20 decreasing during the day, and it has actually been 15-20
increasing to 25-30 with gusts to 50.

More important at the top of every Ocean Prediction Center weather fax
you'll read:
SIGNIFICANT WAVE HEIGHT IS SHOWN (THE AVERAGE HEIGHT OF THE HIGHEST
ONE-THIRD OF THE WAVES)

In other words, the forcasted/observed wave hight means you gonna see
lots bigger ones too. Average = mean.
Bob