The Capture of Tropical Cyclones by Cold Fronts off the West Coast of Australia

Abstract

A climatology of all tropical cyclones that have affected the subtropical west coast of Australia during the 82-year period 1909–1990 is presented. A total of 39 events were recorded, an average of 0.5 per year, although a more realistic estimate of the frequency of occurrence, based on a dataset that included satellite surveillance (1964–1990), suggested a value of 0.7 cyclones per year. Northern sections of the west coast experienced nearly twice the number of cyclones as central and southern sections. Cyclone occurrence was confined to the later part of the tropical cyclone season (nominally November to April) and was most common in March. An examination of mean sea level pressure (MSLP) analyses associated with tropical cyclones in the period 1964–1990 revealed two distinct synoptic patterns. One group of cyclones was characterized by a steady southward movement into a region of environmental easterly flow, and the other by rapid acceleration due to the approach of a frontal system from the c... Abstract A climatology of all tropical cyclones that have affected the subtropical west coast of Australia during the 82-year period 1909–1990 is presented. A total of 39 events were recorded, an average of 0.5 per year, although a more realistic estimate of the frequency of occurrence, based on a dataset that included satellite surveillance (1964–1990), suggested a value of 0.7 cyclones per year. Northern sections of the west coast experienced nearly twice the number of cyclones as central and southern sections. Cyclone occurrence was confined to the later part of the tropical cyclone season (nominally November to April) and was most common in March. An examination of mean sea level pressure (MSLP) analyses associated with tropical cyclones in the period 1964–1990 revealed two distinct synoptic patterns. One group of cyclones was characterized by a steady southward movement into a region of environmental easterly flow, and the other by rapid acceleration due to the approach of a frontal system from the c...