Narelle Approaching a Final Landfall In Australia, Twins Coming? AI Models Discussion 3-25-2026

Cyclone Narelle is intensifying and looks poised to make yet another landfall in Australia, after days of traversing the north side of the continent. The eye of the cyclone is popping out again, and models are showing that it will likely be back up above Category 3 equivalent (100 knots) when it makes landfall somewhere along the Northwest corner of Australia late tomorrow (Figure 1).

After Narelle, the Maritime Continent and Southwest Pacific looks to remain active. In particular, the medium-to-long range guidance suggests that it is possible we could see “Twin Cyclones”, with TCs forming on both the north and south sides of the equator. The possibility for TC formation will be enhanced by the superposition of equatorial waves, including an MJO pulse and Equatorial Rossby Wave (ERW). Some models are enthusiastic about two cyclones developing (Figure 2). 

Others only show a TC developing in the Southern Hemisphere, with a weak trough north of the Equator (Figure 3). This is possible, since seasonally the Southern Hemisphere is currently favored for TC activity.

These possible “Twin TCs” could be important for subseasonal and seasonal evolution in the Pacific. The MJO/ERW pulse will already generate a “Westerly Wind Burst” which will help to push the atmosphere-ocean system towards El Niño. If two TCs do form, the interaction of the two circulations will likely create much stronger westerlies between the two systems, right along the equator (Figure 4).

On the other hand, if only one TC forms, we will still see reduced trades and some westerly winds, but not of the same magnitude (Figure 5). There is a little bit of a chicken-and-egg component to these model differences as well, since a stronger initial WWB will generate more vorticity (spin) and be more likely to spawn multiple TCs.

This next 1-2 week period will likely tell us something about how strong the upcoming El Niño event will be. For reference, the 1982, 1997, and 2015 El Niño events (which were all very strong) featured twin TC events in this region during the Spring. So if we do indeed see a strong WWB induced by twin TCs, it would be another indicator of a top-end El Niño event this year. This will certainly be worth monitoring for climate impacts across the globe.