A case study of the formation of an Eastern Pacific tropical cyclone

A case study is performed to investigate the nature of tropical cyclogenesis in the eastern Pacific Ocean. Focus is given to the formation and development of the initial circulation which eventually intensified into Hurricane Fefa. Using satellite imagery, the author studies the development of convective activity in the genesis region. Gridded reanalysis data are used to document the synoptic-scale flow, with emphasis on tracing the easterly wave which is associated with the formation of Fefa. The data show that the easterly wave propagated across the Caribbean Sea and the Central American mountains, and the initial circulation developed while the wave had moved into the eastern Pacific. The wave is found to have moved through an unstable basic state while it was in the Caribbean, which is favorble for its growth and maintenance. Two phenomena are observed prior to the formation of the low-level circulation. These include an easterly jet in the eastern Pacific that may have been associated with the blocking effect of the Central American mountains, and a southerly wind surge into the monsoon trough region. In addition, aircraft observations collected during Tropical Experiment in Mexico are used to study the evolution of the mesoscale system. Initially, a circulation in the middle troposphere with a cold core in the boundary layer, and a shear line located to the west were found. One day later, a low-level warm core vortex had developed, and it was displaced from the mid-level vortex. It is suggested that the low-level vortex formed from the spin-up of the monsoon trough, independent of the mid-level vortex.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

1999

Author dc:creator

• Kung, Terence, 1974-

Advisor dc:contributor.advisor

• Kerry A. Emanuel.

• Earth, Atmospheric, and Planetary Sciences.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/54440

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/54440