Why do the wind forecasts underestimate the wind speed of hurricanes / tropical cyclones?
The difference in wind speeds between our wind forecasts and the tropical cyclone (tropical depressions, tropical storms, hurricanes, typhoons, etc.) forecasts and warnings issued by official government agencies (such as the US National Hurricane Center) has to do with terminology and the averaging method used. Our wind charts show average wind speeds, while the tropical forecasts and warnings indicate “maximum sustained winds”, which are based on maximum wind gusts, but use a shorter averaging period. These maximum sustained winds tend to be 30-40% higher than average wind speeds. Added to this is the fact that the official government agencies tend to exaggerate the intensity of tropical cyclones, to “be safe”. Therefore, the maximum sustained winds from an official tropical cyclone forecast can be significantly higher than the average wind speeds that our wind forecasts indicate, sometimes as much as 60% higher.
