Observations made at different levels by aircraft of the Research Flight Facility (RFF) of the U.S. Weather Bureau, in conjunction with regular synoptic observations from the coastal United States and Bahamas, are utilized in detailed analysis of conditions prevailing during the crucial period immediately before, during, and after Ella (1962) attained hurricane intensity.
It is shown that, in contrast with other hurricanes described in the literature, Ella did not develop under an upper tropospheric anticyclone. Rather, anticyclonic circulation first appeared in the middle troposphere and gradually extended upward while the storm was intensifying into a hurricane. Correspondingly, the warm-core structure first appeared in the low levels and then spread to the upper troposphere.
Present address: Techniques Development Laboratory, Weather Bureau, Environmental Science Services Administration, Washington, D.C.