Indonesia's Meteorology, Climatology, and Geophysics Agency (BMKG) has forecasted light to heavy rain, lightning, and strong winds in numerous cities on Wednesday, January 7, 2026, due to a convergence area from East Nusa Tenggara to northern Australia. Fishermen in North Sumatra waters face waves up to 2.5 meters through January 8.
BMKG forecaster Miftah Ali attributed the weather to a convergence stretching across East Nusa Tenggara, the Banda Sea, Arafura Sea, South Papua, and northern Australia, prompting moderate to heavy rain with possible lightning and strong winds in cities including Pekanbaru, Tanjung Pinang, Pangkalpinang, Tanjung Selor, Palangka Raya, Kupang, Mamuju, Makassar, and Nabire.
Light to moderate rain is expected in Banda Aceh, Medan, Bandar Lampung, Jambi, Serang, Jakarta, Bandung, Yogyakarta, Surabaya, Semarang, Banjarmasin, Samarinda, Pontianak, Gorontalo, Manado, Kendari, Ternate, Ambon, Sorong, Manokwari, Nabire, Jayapura, Jayawijaya, and Merauke. Areas like Bengkulu, Denpasar, Mataram, Palu, and Manokwari may remain cloudy.
Separately, forecaster Christen Marpaung from the Belawan Maritime Meteorology Station warned of waves 1.25 to 2.5 meters high from January 7-8 in the western Indian Ocean off Nias Islands, waters west and east of Nias, and Batu Islands waters. Fishing boats should beware at wind speeds of 15 knots and wave heights of 1.25 meters; barges at 16 knots and 1.5 meters.
These alerts aim to boost public preparedness for potential disruptions to daily activities.