These high tech weather instruments anchored out at sea provide valuable data to the mariner.
They give a glimpse of current ocean conditions by reporting the wind speeds and swell heights
every hour via satellite. If you are lucky enough to have one nearby, a check of the local buoy report can alert you to unfavorable or life
threatening ocean conditions. BuoyWeather provides a different way of looking at the data. The pages
emphasize graphs for easy trend analysis and adds a height and period derived surf forecast. One of the great uses for buoys is estimating surf along nearby shores. There are three pages of data for each NOAA buoy.
Standard Report: You'll get the latest report plus 12 hour plots of significant
swell height and wind speed, pressure, water temp, air temp. If you see a "MM" in the
report it means missing data. Sometimes the gauges are broken.
Swell Detail: The Ocean can have many overlapping swells crossing the same point.
The buoy reports the primary wind swell and primary ground swell. The wind swell
(3 - 10 second period) which is the chop generated by local and current winds, and a ground
swell (10 - 25 sec) which has traveled possibly 5000 miles. A high wind swell means warning
to small craft. Wind swells are steeper and more dangerous at sea. A high ground swell means
opportunity if you are a surfer and also warning if you are an inexperienced swimmer going to
the beach. Long period swells hit the shore with more power, but may be hardly noticed when you
are out at sea because of 20 second spacing between crests.
Spectral Density: A deeper look into the swell makeup. This page was designed to find
secondary ground swells and show long period energy trends. There are times when there are
two or more concurrent ground swells. The Buoy picks the strongest one for the swell reading,
but the unreported second one may also be significant. A good example of the need for this is
in Hawaii. Because of a persistent trade wind swell, smaller long period south swells may exist
unreported by the Buoy's swell report. These hidden swells will show up in this report. Swells
are characterized by their associated periods. The top graph shows the wave energy for each
period. Each peak in the graph represents a separate swell. If there are two peaks, the buoy
reports the one with the highest energy. You can find the second hidden swell here. A new swell will
also show up here first before it gets reported. Look for increasing 16-20 energy trends that
signal new swell arrival.