The Relationship between Sea Surface Temperatures and Maximum Intensities of Tropical Cyclones in the Eastern North Pacific Ocean

An empirical relationship between climatological sea surface temperatures (SST) and the maximum intensities of tropical cyclones over the eastern North Pacific Ocean is developed from a 31-yr sample (1963–93). This relationship is compared with an empirical relationship for tropical cyclones over the Atlantic Ocean and with theoretical results. Over the period of study, the storms over the eastern North Pacific Ocean reached a lower percentage of their empirical maximum potential intensity (MPI) than tropical cyclones over the Atlantic Ocean. At the time of their maximum intensity, only 11% of eastern North Pacific storms reach 80% of their MPI, while 19% of the Atlantic tropical cyclones reach that proportion of their MPIs. Poleward recurvature of Atlantic storms over cooler waters appears to be a major factor in the difference between the two regions. The storms were stratified by latitude, longitude, the phase of the quasi-biennial oscillation (QBO), and the status of the El Niño phenomenon. Tropical cyclones that develop west of 110°W tend to reach a higher percentage of their MPI than storms developing farther east. Tropical cyclones also tended to reach a higher percentage of their MPI and to attain higher maximum intensities when the QBO was in its westerly phase.