Tropical Cyclone Seedling 90S Developing, BMKG Warns of Extreme Weather Potential 2-8 March

Indonesia’s Meteorology, Climatology and Geophysics Agency (BMKG) has identified the development of Tropical Cyclone Seedling 90S in the Indian Ocean south of Central Java. The tropical cyclone seedling could trigger increased rainfall ranging from heavy to very heavy across various Indonesian regions from 2-8 March 2026.

Andri Ramdhani, Acting Deputy for Meteorology at BMKG, explained that Tropical Cyclone Seedling 90S is currently estimated to be located in the Indian Ocean south of Central Java. Additionally, low-pressure systems positioned in the Pacific Ocean north of Papua, the Carpentaria Gulf, and the north-western coast of Australia are also influencing Indonesia’s weather.

“Tropical Cyclone Seedling 90S and low-pressure systems around Papua and Australia are forming a wind convergence zone. This supports the development of very massive rain clouds throughout the convergence area,” Andri told reporters on Tuesday, 3 March 2026.

According to BMKG data, extreme rainfall has already affected West Papua with intensities reaching 133.2 mm per day during the period from 26 February to 1 March 2026. During the same period, heavy rainfall also battered Yogyakarta, Surabaya, and North Maluku.

This condition resulted from a combination of Cyclone Seedling 90S, the convergence of monsoon winds with westerly winds, and the activity of the Madden-Julian Oscillation (MJO) phenomenon and Kelvin and Rossby waves, which accelerated rain cloud formation.

Meanwhile, global conditions show a weak category La Niña remains active, increasing water vapour supply particularly in eastern Indonesian regions. Furthermore, MJO activity is predicted to move into phases 5 and 6 (western Pacific region), which would significantly contribute to rain cloud formation across most Indonesian regions, particularly in the South China Sea, the south-western Indian Ocean near Lampung to East Nusa Tenggara (NTT), Bali, West Nusa Tenggara (NTB), NTT, the southern coast of Java, waters north of Bali to northern NTT.

Ida Pramuwardani, Acting Director of Public Meteorology, added that these conditions have the potential to increase moderate to heavy rainfall intensity across several regions on 2-4 March 2026, including Sumatra, parts of Java, Bali, Kalimantan, Sulawesi, Gorontalo, North Maluku, Maluku, South-West Papua, West Papua, Mountainous Papua, and Papua.

“The public should also be alert to the potential for heavy to very heavy rainfall (Alert status) in Java, Bali, NTB, NTT, South Kalimantan, and South Sulawesi regions; as well as strong winds in Yogyakarta, East Java, Bali, NTB, NTT, Maluku, and Southern Papua,” she said.

During the period of 5-8 March 2026, weather conditions are expected to be dominated by light to moderate rainfall. However, in several regions, BMKG has advised the public to remain alert to potential increases in intensity to moderate to heavy levels, particularly in parts of Sumatra, Java, Bali, NTB, NTT, Kalimantan, Sulawesi, North Maluku, Maluku, and Papua.

Additionally, heavy rainfall that may be accompanied by lightning and strong winds remains likely, with Alert status (heavy to very heavy rainfall) potentially occurring in South Sumatra, the Bangka Belitung Islands, Banten, Jakarta, West Java, East Java, and NTT. Strong winds are also potential in East Java, Bali, NTB, NTT, and Maluku.