Reason why Hurricanes seem stronger
Posted 12-16-2019 at 07:04 PM by Cambium
There are two ways to determine the strength of a hurricane. One is to measure the winds with an airplane. The Air Force always flies at 10,000 ft. and empirical relationships are used to convert the 10,000 ft. winds to surface winds. The other is to drop a barometer into the eye and measure the pressure. Since there is a direct relation between the pressure and the wind, if you know one you can compute the other.
Historically, the central pressure was the predominate factor in determining the strength of a hurricane. When the Saffir/Simpson hurricane scale was developed in the early 1970s, all past hurricanes were ranked on the Saffir/Simpson hurricane scale according to their central pressure. Today that policy has changed and now hurricanes are ranked exclusively by the wind. That is why it was possible to declare Irma was the strongest hurricane ever observed in the Atlantic when the plane reported 185 mph winds. But, what does the central pressure tell us about Irma?
How does Irma compare with other strong historical hurricanes if we use the central pressure to determine the strength rather than wind? The lowest central pressure recorded in Irma was 914 millibars. The lowest pressure ever recorded in an Atlantic hurricane was 882 mb while Wilma was in the northwest Caribbean Sea in 2005. The lowest pressure for a land falling hurricane was 892 mb when the 1935 hurricane crossed the Florida Keys. There have been 10 hurricanes with central pressures below 910 mb of which 5 were below 900 mb. Irma did not even make the top 10; therefore, it was not close to being the strongest hurricane ever observed In the Atlantic.
https://twitter.com/wxbywilliams/status/912734366941503490/photo/1
Historically, the central pressure was the predominate factor in determining the strength of a hurricane. When the Saffir/Simpson hurricane scale was developed in the early 1970s, all past hurricanes were ranked on the Saffir/Simpson hurricane scale according to their central pressure. Today that policy has changed and now hurricanes are ranked exclusively by the wind. That is why it was possible to declare Irma was the strongest hurricane ever observed in the Atlantic when the plane reported 185 mph winds. But, what does the central pressure tell us about Irma?
How does Irma compare with other strong historical hurricanes if we use the central pressure to determine the strength rather than wind? The lowest central pressure recorded in Irma was 914 millibars. The lowest pressure ever recorded in an Atlantic hurricane was 882 mb while Wilma was in the northwest Caribbean Sea in 2005. The lowest pressure for a land falling hurricane was 892 mb when the 1935 hurricane crossed the Florida Keys. There have been 10 hurricanes with central pressures below 910 mb of which 5 were below 900 mb. Irma did not even make the top 10; therefore, it was not close to being the strongest hurricane ever observed In the Atlantic.
https://twitter.com/wxbywilliams/status/912734366941503490/photo/1
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