Event Title

Hurricane Seedlings

Start Date

4-1971 8:00 AM

Description

It is generally recognized that hurricane formation occurs within a pre-existing region of disturbed weather and the dynamical and thermodynamical processes responsible for the disturbed weather are of several different types depending upon the source of energy that feeds the system. Disturbances in which air motion results from cold air underriding and displacing warm air are known as "Baroclinic systems". These are common over subtropical portions of the oceans and are more frequent in the spring and fall. A more common system in the tropics is similar to a simple mechanic heat engine and is driven by the release of latent heat of condensation. Finally, other systems draw from both sources of energy.

In the past it has not always been possible to properly recognize nor to document the history of such disturbances over large expanses of the tropical Atlantic Ocean with conventional data. During the last four years, satellites have provided us an opportunity, for the first time, to accurately identify and follow these "hurricane seedlings".

On the average, approximately 100 "hurricane seedlings" occur each year during hurricane season which extends from June 1 to November 30. One of ten become named storms and one of ,four develop a closed wind center characteristic of a depression. This means that one of every three depressions intensify and become a named storm.

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Apr 1st, 8:00 AM

Hurricane Seedlings

It is generally recognized that hurricane formation occurs within a pre-existing region of disturbed weather and the dynamical and thermodynamical processes responsible for the disturbed weather are of several different types depending upon the source of energy that feeds the system. Disturbances in which air motion results from cold air underriding and displacing warm air are known as "Baroclinic systems". These are common over subtropical portions of the oceans and are more frequent in the spring and fall. A more common system in the tropics is similar to a simple mechanic heat engine and is driven by the release of latent heat of condensation. Finally, other systems draw from both sources of energy.

In the past it has not always been possible to properly recognize nor to document the history of such disturbances over large expanses of the tropical Atlantic Ocean with conventional data. During the last four years, satellites have provided us an opportunity, for the first time, to accurately identify and follow these "hurricane seedlings".

On the average, approximately 100 "hurricane seedlings" occur each year during hurricane season which extends from June 1 to November 30. One of ten become named storms and one of ,four develop a closed wind center characteristic of a depression. This means that one of every three depressions intensify and become a named storm.

 

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