The role of easterly waves in the formation of East Pacific tropical cyclone precursors

The relation between easterly waves that propagate from over the Caribbean Sea toward the East Pacific Ocean and the episodic, localized deep convection that frequently occurs over the Gulf of Tehuantepec is examined using IR satellite imagery and gridded wind data. The episodes of deep convection are important since the resulting disturbances often become organized and develop into East Pacific tropical cyclones. These convective outbreaks are also important in modulating the structure of the ITCZ in the East Pacific.

This study shows that there is a correlation between synoptic-scale disturbances present over the Caribbean at the time that deep convection begins over the Gulf of Tehuantepec. These disturbances propagate from the east with a phase speed, horizontal and vertical structure characteristic of easterly waves.