BMKG Warns of Extreme Weather Threat in Southern Indonesia Late January

TEMPO.CO, Jakarta - The Indonesian Meteorology, Climatology, and Geophysics Agency (BMKG) is urging the public to increase their vigilance regarding the potential for increased extreme weather in parts of Indonesia. Based on the latest atmospheric dynamics analysis, the region encompassing southern Sumatra, Java, Bali, and Nusa Tenggara is predicted to experience increased rainfall intensity towards the end of January 2026. BMKG Head Teuku Faisal Fathani explained that the currently observed atmospheric disturbances are triggering significant growth of convective clouds, or rain clouds, in southern Indonesia. He said this condition could trigger potential flooding, landslides, and disruption to the transportation sector in affected areas. "We urge the public to remain calm but remain vigilant in the face of potential extreme weather towards the end of January," Faisal said in a written statement on Wednesday, January 21, 2025. BMKG Acting Deputy for Meteorology Andri Ramdhani explained that several technical factors will influence weather conditions over the next week. Among them is the presence of Tropical Cyclone 97S in the Indian Ocean south of Indonesia. Its westward movement, he stated, could trigger a strengthening of wind convergence and deflection from the west coast of Sumatra to Nusa Tenggara, "which could trigger increased rain cloud formation in southern Indonesia." On the other hand, the Asian Monsoon is predicted to continue strengthening until January 23, 2026, accompanied by a significant cold surge from mainland Asia. Andri explained that this phenomenon increases wind speeds in the South China Sea and triggers massive rain cloud growth in the region south of the equator. Furthermore, simultaneously, the Madden-Julian Oscillation (MJO), Equatorial Rossby Waves, and Kelvin Waves are also active, strengthening the formation of Cumulonimbus clouds in the atmosphere. These conditions, he said, combine with high humidity in the lower to middle layers of the atmosphere. This strong atmospheric lability fully supports local-scale convective processes in southern Indonesia. "The combination of all these factors actively triggers the potential for extreme weather in various affected areas," said the Director of Public Meteorology at the Meteorology, Climatology, and Geophysics Agency (BMKG). Atmospheric dynamics analysis indicates that heavy rain accompanied by lightning and strong winds will potentially affect most parts of Indonesia in succession towards the end of January 2026. On January 21, extreme weather is likely to occur in Bengkulu, Lampung, Banten, Jakarta, West Java, Central Java, Yogyakarta, East Java, Bali, West Nusa Tenggara, and East Nusa Tenggara. Entering January 22, the potential for similar weather impacts continues to loom over Bengkulu, Jakarta, West Java, Central Java, East Java, Bali, West Nusa Tenggara, and East Nusa Tenggara. This will continue on January 23 in Jakarta, West Java, Central Java, East Java, West Nusa Tenggara, and East Nusa Tenggara. Furthermore, extreme weather intensity is likely to occur in Central Java and East Java on January 24. The Meteorology, Climatology, and Geophysics Agency (BMKG) predicts that Bali, West Nusa Tenggara, and East Nusa Tenggara will experience increased rainfall between January 25 and 26. "These weather dynamics require high vigilance from the people of these provinces to anticipate the impacts of potential hydrometeorological disasters," said Andri. Read: Jakarta Stays on Heavy Rain Alert Through Thursday, Says BMKG