October is surprisingly dry across much of Australia especially in the East. Wet weather is confined to the northwest to south-central coast of the continent. Anomalous heat has dominated October with impressive anomalous daytime heat across East Australia. The East Australia heatwave fades due to sudden heavy rains to finish October.

RI (rapid intensification) is defined as a tropical cyclone gaining more than 35 mph in top wind speed within 24 hours. On the weekend, an upper-level high pressure builds east-northeast of Melissa forcing a discernable northwest steering current. During this time, upper-level shear eases. As Melissa moves northwest in an improving environment, the storm is better able to intensify rapidly moving across 30-31C surface water and the 3rd warmest upper ocean heat content on record for the Caribbean Sea.

One cold front has plowed into Northeast Brazil this week and another stronger front shifts across Argentina late week/early weekend. The second front delivers a widespread cool air mass for next week across Argentina. The supporting upper trough cuts off over central South America in early November to deliver wet weather to the Brazil drought zone.

The Madden Julian oscillation (MJO) remains active. The eastward shifting MJO in the tropical Indian Ocean (phase_3) to the Maritime Continent (phase_5) over the next 2 weeks will influence climate Australia and South America plus the West Pacific tropics to the U.S.