Tropical Climate Update

First Australian tropical cyclone for 2020–21

Tropical cyclone Imogen was the first Australian tropical cyclone for season 2020–21 when it developed late on Sunday, 3 January 2021. Imogen was close to the eastern coastline of the Gulf of Carpentaria when it reached tropical cyclone intensity and made landfall as a category 1 storm near Karumba, Queensland, soon after. Imogen was downgraded to an ex-tropical cyclone during the morning of Monday, 4 January.

Minor wind damage was reported in the vicinity of Karumba, and heavy rainfall was observed about the southeastern Gulf coast. The highest daily rainfall total was at Normanton, Queensland, with 262 mm in the 24 hours to 9am on 4 January.

Ex-TC Imogen is forecast to move eastwards across Cape York Peninsula in coming days, but there are currently no predictions that this tropical low will redevelop to tropical cyclone strength if it moves over the Coral Sea. Heavy rainfall for parts of Queensland's north is expected to continue in the coming days due to ex-TC Imogen and a weak monsoon trough which extends from the tropical low into the Coral Sea.

Read more about Australian tropical cyclone warnings and information

Madden–Julian Oscillation moves into the Indian Ocean

A pulse of the Madden–Julian Oscillation (MJO) is currently located in the Indian Ocean. This pulse is relatively weak, but most climate models predict some strengthening, accompanied by slow eastwards movement, in the coming week. In its current location an MJO pulse would typically not increase the likelihood of above-average rainfall across northern Australia. With most models predicting a weakening of the MJO prior to reaching the Maritime Continent, an increase in rainfall across northern Australia due to the MJO's influence is not expected in the coming fortnight.

Read more about the Madden–Julian Oscillation

Monsoon break conditions likely to prevail across northern Australia

With no significant MJO or other tropical atmospheric wave activity expected in Australian longitudes for at least the next fortnight, inactive, or monsoon break, conditions are likely to become established across northern Australia in the coming days. This usually means rainfall activity becomes less frequent and more isolated than when the Australian monsoon is in an active phase. The risk of tropical cyclone development returns to normal, or below normal, levels and rainfall across northern Australia is influenced more by day-to-day weather patterns than short-term climate divers such as the MJO.