The Northern region outlook suggests an average number of tropical cyclones with a 53% chance of more tropical cyclones than average and a 47% chance of fewer tropical cyclones than average. In a typical year the Northern region experiences around three cyclones, and one or two tropical lows that later become cyclones after moving into the Western or Eastern regions. About three-quarters of the tropical cyclones in the Northern region impact coastal regions. Outlook accuracy for this region is very low.
The Eastern region outlook shows a near average season is most likely, with a 54% chance of more tropical cyclones than average and a 46% chance of fewer. About a quarter of tropical cyclones in the Eastern region make landfall. Outlook accuracy for this region is low.
There have been some reports of a mild La Nina event developing in the Pacific such as this recently at the AFR: Meet La Niña, the little girl spreading fear in commodity market
The BOM do cover this possibility at the Weekly Tropical Climate Note:
Sea surface temperatures (SSTs) across the equatorial Pacific Ocean have warmed marginally in the last week as a result of weakened trade winds. The SST pattern across the equatorial Pacific Ocean is currently indicative of an ENSO-neutral state. Atmospheric indicators also depict an ENSO-neutral state.
A majority of international climate models surveyed by the Bureau suggest further cooling of the tropical Pacific Ocean is likely. Five of the eight models suggest SSTs will cool to La Niña thresholds by December 2017, but only three maintain these values for long enough to be classified as a La Niña event.
It is not unprecedented for La Niña to develop this late in the year, however it is unusual. Of the four late-developing La Niña events on record, three have coincided with above-average wet-season rainfall across northern Australia.
See the Bureau’s current ENSO Wrap-Up for more information
Tinaroo Falls is currently at 42% capacity so would probably appreciate a somewhat wetter than average season. Rainfall down at Cairns Aero has trended below average for several years now following the severe 2011 La Nina period.
Don’t start me on the period used by the Commonwealth Actuary for his insurance study. Probably worth keeping a weather eye on global catastrophe reinsurance markets also following the US hurricane season.