Heavy Rain Continues in Florida; Cold Front Brings Thunderstorms and Showers to Central US

Scattered areas of heavy rain continue to produce isolated flash flooding across the Florida peninsula. Anomalous moisture will combine with a cold front and will bring heavy rain and scattered flash flooding across the Mid-South, Ohio and Tennessee Valleys today and Tuesday. Above average temperatures will continue to be found ahead of the cold front from the Midwest to the Northeast. Read More >

Significant Wave Height
Commonly Referred to as Seas in the Marine Forecast

This is the average of the highest one-third (33%) of waves (measured from trough to crest) that occur in a given period. This is measured because the larger waves are usually more significant than the smaller waves. For instance, the larger waves in a storm cause the most beach erosion, or the larger waves can cause navigation problems for mariners. Since the Significant Wave Height (Seas) is an average of the largest waves, you should be aware that many individual waves will probably be higher. On average, about 15% of waves will equal or exceed the significant wave height. Occasional seas are the average height of the highest 10 percent of the waves. The occasional seas could be 25-30% higher than the significant wave height.

If we take a sample forecast of Seas Beyond the Reef of 2 to 4 feet, this implies that the average of the highest one-third waves will have a Significant Wave Height of 2 to 4 feet. But mariners need to keep in mind that roughly one of every ten waves will be greater than 4 feet; one in every one hundred waves will be greater than 5 feet; and one in every 1000 waves will be greater than 6 feet.

As a general rule, the largest individual wave one may encounter is approximately twice as high as the Significant Wave Height (or Seas).

Note: Seas can refers to the combination or interaction of wind waves and swells (combined seas) in which the separate components are not distinguished. This includes the case when swells are negligible or are not considered in describing sea state.

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Heavy Rain Continues in Florida; Cold Front Brings Thunderstorms and Showers to Central US

Significant Wave Height

Significant Wave Height Commonly Referred to as Seas in the Marine Forecast

Significant Wave Height
Commonly Referred to as Seas in the Marine Forecast