There are early signs that a strong tropical cyclone could spin up over the Coral Sea next week as three broad-scale tropical atmospheric waves converge to the northeast of Australia.

What are tropical atmospheric waves?

Weather in Earth’s tropical regions is influenced by large-scale areas of low and high pressure moving through the atmosphere. These ‘tropical waves’ can enhance or suppress rainfall and thunderstorms and help create tropical cyclones.

There are four main atmospheric waves that affect tropical weather in the Australian region:

The Madden–Julian Oscillation (MJO) moves around the planet near the equator from west to east, causing an area of increased cloud and rainfall that recurs roughly every 30 to 60 days.

Equatorial Kelvin waves, which also move from west to east, are alternating areas of high and low pressure that cause alternating regions of cloudiness/rainfall and clear weather. These waves move around 2 to 3 times faster than the MJO.

Equatorial Rossby waves are alternating areas of high and low pressure that sit around 10 degrees north and south of the equator and move from east to west. These waves can cause low pressure systems and regions of cloud and rain to mirror each other at similar longitudes on both sides of the equator. These waves travel at a similar speed to the MJO, but in the opposite direction.

Mixed Rossby-Gravity waves move from east to west and are much faster than regular Equatorial Rossby waves. They cause contrasting areas of high and low pressure on either side of the equator, which can cause enhanced cloudiness and rainfall on one side of the equator and dry weather on the other.

Three waves converging next week

Three of the four tropical waves mentioned above are expected to converge near Australia next week. An active pulse of the Madden-Julian Oscillation will interact with a Kelvin wave and an Equatorial Rossby wave to the northeast of Australia during the first week of April.

This convergence of three tropical atmospheric waves is likely to enhance cloudiness and rainfall over the western Pacific Ocean, possibly including parts of the Solomon Islands, Papua New Guinea, Indonesia and northern Australia.

The influence of the Equatorial Rossby wave may cause two areas of low pressure to spin up next week, one in the Southern Hemisphere near the Solomon Islands and another at a similar longitude in the Northern Hemisphere.

Image: Modelled water vapour and 850 hPa wind showing twin tropical lows on either side of the equator on April 7, 2026. Source: Weatherzone.

There are early indications that the Southern Hemisphere low pressure system could intensify over the warm northern Coral Sea, where sea surface temperatures are currently 28 to 30°C, possibly becoming a tropical cyclone mid- to late next week. Some models even suggest it could become a severe tropical cyclone.

It’s too early to know with much confidence if there will be a tropical cyclone over the Coral Sea next week and if so, whether it will approach eastern Australia or remain offshore.

However, with three tropical atmospheric waves converging in the region, meteorologists will be keeping a close eye on the Coral Sea region as we head into the first half of April.