For a given forecast time:

(1)  Get the Swell Height immediately adjacent to the beach of interest (Hs) from the WaveWatch or REFDIF (if available) forecast charts available from the previous page.

(2)  If Hs is obtained from WaveWatch, estimate Angle of Incidence (A) as the angle between the Swell Direction on the WaveWatch Swell Direction forecast chart and a line perpendicular to the coastline at the beach of interest.  For example, if beach runs exactly north-south and waves are approaching from a direction of 60 degrees from true north, then A equals 30 degrees.  Note:  if Hs is obtained from REFDIF, assume A = 0 as the REFDIF calculations already take into account the effect of non-zero Angle of Incidence.

(3)  Get the Swell Period immediately adjacent to the beach of interest (Ts) from the WaveWatch forecast.

(4)  Select the link to the appropriate Surf Height Table below based on closest approximation to the offshore Slope of the beach of interest and the Angle of Incidence, A.

     Gentle to Moderate Beach Slope (characteristic of most beaches around the Continental United States):
           A =   0 degrees
           A = 15 degrees
           A = 30 degrees
           A = 45 degrees
           A = 60 degrees
           

     Moderate to Steep Beach Slope:
           A =   0 degrees
           A = 15 degrees
           A = 30 degrees
           A = 45 degrees
           A = 60 degrees
           A = 75 degrees

(5)  Finally, enter the selected Surf Height Table with forecast Hs and Ts  to obtain forecast surf height range.  Occasional set waves will be about 25% higher than the upper range of wave heights depicted in the table.