1. It has an uncanny ability to predict wave heights for W and NW swells in north county San Diego. Since all swells at our local beaches are dependent on swell angle, the information shown above is vital to gauging how big the waves are going to be. If you'll look at the 'N. Pac.' (North Pacific) reading it says 7.5 feet at 14 seconds from 270 degrees. 270 degrees is pretty head on for north county as we face 240 degrees- so we'll have little swell decay when the waves finally break at our local beaches. For this particular reading, wave heights are around head high for us. Now if the reading was over 300 degrees, the swell has to bend quite a bit to fit our 240 angle, so the wave heights may be 1/2 the 7.5' swell- so the waves around town here may only turn out to be waist to chest high.
2. Another important reading from the Harvest buoy is the swell interval. For the N. Pac. reading above, it's about 14 seconds. Storms that form far away will have readings above 12 seconds. So this 14 second reading is probably a groundswell. Windswell on the other hand is short interval and choppy- somewhere in the 8-10 second range- and probably short lived. Good solid lined up groundswells from the middle to far part of the North Pacific will be in the 18-20 second range and may last a few days. Let's say the Harvest Buoy for a few days was a meager 4' at 10 seconds. Then one morning you wake up and notice it's 8'at 20 seconds. You'll know you've got some serious swell on the way. Let's say 24 hours later you see a reading of 4' at 12 seconds- you know the swell has passed it's peak.
3. What's also interesting about using this info is if it has been flat for a few days and you notice the reading pop up to 8' at 20 seconds, it will take about 6 hours for the swell to get from Point Conception to San Diego. So don't go running down to your local break right away- you have some time to get ready.
As far as the S. Pac. (South Pacific) readings go, it's not summer time yet and it's a whole other story with that one...
