Definitions for "MHHW"
Keywords:  tide, tidal, height, epoch, average
Mean Higher High Water. The average height of the higher high waters over a 19-year period.
mean higher high water. A tidal datum. The average of the higher high water height of each tidal day observed over the National Tidal Datum Epoch. For stations with shorter series, simultaneous observational comparisons are made with a control tide station in order to derive the equivalent datum of the National Tidal Datum Epoch.
The average of the higher " Highest astronomical tide" heights of each tidal oscillation observed over a period of 19 years.