The Bureau of Meteorology issued its annual tropical cyclone season outlook Monday, pointing to an above-average number of tropical cyclones for all four regions across northern Australia during the coming season.

The Bureau of Meteorology's climate prediction manager, Dr Andrew Watkins, said climate models were trending toward another La Niña, which would lead us to expect a slightly higher than average number of tropical cyclones. But no two La Niña events are the same.

“The Southern Oscillation Index, a key climate driver, was (positive) 11.7 in September this year, compared with (positive) 25 at the same time last year. While this La Niña may be weaker than the last, this doesn’t mean we can expect fewer tropical cyclones than the previous season. In other words, we can’t afford to be complacent,” said Watkins.

Bureau of Meteorology climatologist Joel Lisonbee said before a tropical cyclone forms it is difficult to predict its exact strength and path and whether it will make landfall, however, we have a solid body of historical data which gives us a likely range in which to work.

“Along the east and west coasts, less than half of all cyclones affect the coast, with most staying out to sea. However, along the north coast more than half of all cyclones will impact coastal regions,” said Lisonbee.

“During a La Niña, warmer waters in the western Pacific and regions to the north of Australia, and associated changes in circulation help focus tropical cyclone activity in the Coral and Timor seas,” he said.

“Generally we divide Australia into four regions with the average number of tropical cyclones in the eastern region (Queensland) being four, northern region (Northern Territory) being three, and western region (Western Australia) being seven. The northwestern subregion, which includes Western Australia and the Northern Territory, is highly active and with an average of five tropical cyclones,” said Lisonbee.

Tropical cyclone season in the southern hemisphere usually runs between November and April. Australia operates Tropical Cyclone Warning Centres in Perth, Darwin and Brisbane.