Maritime Continent Getting Active: AI Models Discussion 2-27-2026

The Southern Hemisphere TC season is in full swing. As a large-scale pulse of rising air associated with the MJO (Madden-Julian Oscillation) moves from West to East, it is currently passing over the Maritime Continent and Australia region. As a result, we can expect generally lower surface pressure (Figure 1) and rainfall across this region.

As a result of this increased rising air and general favorable environment, TC activity will likely be favored in this region over the next week or two. One TC has already formed, Cyclone Urmil near Vanuatu. Thankfully it is forecast to move off to the southeast and not impact any land areas, but more development is likely in the coming days (Figure 2).

The TC activity looks to form as a result of a breakdown of the monsoon trough in the region. The sharp gradient between westerlies along the equator and the easterlies to the south (Figure 3) will create a large area of vorticity (spin), and as convection helps to concentrate the spin, we could

see as many as 2-3 areas of low pressure consolidate (Figure 4).

It is also possible that as the MJO moves through, we could see tropical development on the Northern Hemisphere side in the West Pacific. Upper-level winds are forecast to be favorable for development, with a large upper anticyclone overhead (Figure 5).

Regardless of development, it appears that there will be an area of westerly winds in the deep tropics as this pulse moves across (Figure 6). This will likely serve to further enhance subsurface warmth in the West Pacific and potentially generate another downwelling Kelvin Wave, likely helping to speed up a potential transition to El Niño by this summer.