BMKG: Heavy Rain and Strong Winds Still Possible in Several Regions
The Meteorology, Climatology, and Geophysical Agency (BMKG) has warned of significant weather conditions persisting across several Indonesian regions from 26 May to 1 June 2026. Activity from Tropical Disturbance 99W and atmospheric waves is expected to trigger heavy rainfall, lightning, and strong winds in various areas, even as some regions enter the dry season.
In its weekly weather forecast, BMKG noted that current atmospheric conditions are influenced by regional and global dynamics, including the Madden-Julian Oscillation (MJO), Kelvin waves, Equatorial Rossby waves, and the formation of several cyclonic circulations around Indonesia. ‘Regional atmospheric dynamics still pose a risk of rain cloud development, particularly in northern Indonesia,’ BMKG stated.
Maximum temperatures exceeding 35 degrees Celsius were recorded in Aceh, Riau, Bali, Kalimantan, Central Sulawesi, West Papua, and East Java from 21-24 May 2026 due to minimal cloud cover causing intense surface heating. Meanwhile, heat accumulation has also led to atmospheric instability, promoting rain cloud formation in the late afternoon and evening in transitional season areas.
BMKG reported heavy to very heavy rainfall in recent days in West Kalimantan (129.5mm/day), Jakarta (102.4mm/day), Bengkulu (96.4mm/day), Maluku (88.4mm/day), and West Java (86.9mm/day). Tropical Disturbance 99W is forecasted to be north of Papua New Guinea, creating a convergence zone from West Papua to Cendrawasih Bay. Cyclonic circulations are also expected off the west coast of West Sumatra, southwest of Banten in the Indian Ocean, and in the Sulu Sea.
From 26-28 May, moderate to heavy rain is possible in Aceh, West Sumatra, Riau, Riau Islands, Jambi, South Sumatra, Bengkulu, Lampung, Banten, Central Java, East Java, Kalimantan, Sulawesi, Maluku, and Papua. BMKG has issued a heavy rain alert for North Kalimantan, North Maluku, and Papua Highlands, with strong winds likely in Aceh, East Java, West Nusa Tenggara, East Nusa Tenggara, Maluku, and Papua.
From 29 May to 1 June, moderate rain is expected in Aceh, Riau, East Java, West Kalimantan, North Kalimantan, Sulawesi, Maluku, and Papua, with a heavy rain alert remaining in Papua Highlands. BMKG urges the public to remain vigilant against hydro-meteorological disasters such as floods, waterlogging, fallen trees, and lightning strikes. Residents are advised to limit outdoor activities during heavy rain with strong winds and regularly check official BMKG weather updates.