Two Unusual Tropical Cyclones in the Southeast Pacific

Abstract

The unusual concurrent development of two strong tropical cyclones in the southeast Pacific during February 1989 is seen from GOES 7 satellite imagery. A review of past tropical cyclone activity in the region is presented which shows that these storms were rare in several aspects. An analysis of mean weather conditions is conducted and indicates that a deep layer easterly wind anomaly with reduced vertical wind shear coupled with warmer than nonnal sea surface temperatures were important contributing factors in the storms' development.