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MJO enhancing tropical cyclone risk in northern Australia

Source Weatherzone Wed 29 Jan 2025

An active pule of the Madden Julian Oscillation (MJO) will increase rainfall over parts of northern Australia in the coming week, while also ramping up the risk of tropical cyclone activity in the first half of February. What is the Madden Julian Oscillation? The MJO refers to a region of enhanced cloudiness and thunderstorm activity that moves around Earth from west to east near the equator. The MJO typically recurs every 30 to 60 days and when it is active near the Australian region, it typically produces rain and thunderstorms over northern Australia. The presence of the MJO can also help spawn tropical cyclones near Australia.   Image: Animation showing the typical movement of an active MJO pulse through the Australian region. The MJO is currently active to the north of Australia and is expected to influence weather in the Australian tropics for the next one to two weeks. In addition to the MJO, another tropical wave called an equatorial Kelvin wave is expected to pass to the north of Australia in the opening days of February. The coincidence of the MJO and Kelvin wave will increase the likelihood of monsoonal rainfall, thunderstorms and tropical cyclones in the next week or two. Forecast models are reacting to presence of the MJO and Kelvin wave, predicting plenty of rainfall over parts of northern Australia in the next fortnight. There is also a good chance that the monsoon trough will form over northern Australia during this MJO burst, which is a sight that has been conspicuously absent so far this wet season. Darwin has not yet seen the monsoon trough this season, which makes this the latest monsoon onset at Darwin on record. The map below shows the predicted accumulated rainfall over northern Australia in the next 10 days from two different computer models.   Image: Forecast accumulated rain during the 10 days ending on February 7, 2025, according to the ECMWF-HRES model.   Image: Forecast accumulated rain during the 10 days ending on February 7, 2025, according to the ACCESS-G model. Some areas are already starting to see heavy tropical rainfall, with a developing low pressure system dumping 200-500 mm of rain on Qld’s North Tropical Coast in the last couple of days. The heaviest rain in the 48 hours to 9am on Wednesday fell between Cairns and Ingham, including: 538 mm at Clyde Road, near the Russel River to the northeast of Babinda 406 mm at Aloomba 338 mm at Gordonvale 342 mm at Cairns Racecourse (makes 342 mm in 48 hours to 9am Wednesday) The low that soaked Qld’s North Tropical Coast over the past few days is one of five tropical lows being monitored by the Bureau of Meteorology for possible tropical cyclone development in the coming week. These low pressure systems, some of which are yet to develop, could span an area stretching more than 5000 km from the Coral sea to the Indian Ocean.   Image: Tropical cyclone risk map for Saturday evening. Source: Bureau of Meteorology It’s currently too early to know where and how many tropical cyclones will develop over the coming week, and if any will make landfall over the Australian mainland. However, with the MJO and a Kelvin wave in the region, anyone in northern Australia should keep a close eye on the latest tropical cyclone forecasts and advisories over the next couple of weeks. - Weatherzone © Weatherzone 2025