Severe weather

The Meteorology, Climatology and Geophysics Agency (BMKG) issued an early warning of the potential for moderate to heavy rain with lightning and strong winds in a number of major cities in Indonesia on Friday, November 13.BMKG Praktirawan Gina said that the current atmospheric dynamics showed the potential for the formation of rain clouds due to the slowdown and meeting of winds in the Andaman Sea region, north of Aceh to North Sumatra, as well as the waters of West Sumatra."This condition has the potential to increase the growth of rain clouds in most of these areas," said Gina, quoted by Antara, Friday morning.BMKG estimates that a number of cities have the potential to experience moderate to heavy rain accompanied by lightning and strong winds. The areas that need to be aware of these conditions include Medan, Bandar Lampung, Serang, Banjarmasin, Mamuju, Nabire, and Merauke.Meanwhile, light rain is predicted to occur in Banda Aceh, Pekanbaru, Padang, Tanjung Pinang, Jambi, Pangkal Pinang, Palembang, Bengkulu, Jakarta, Bandung, Semarang, Yogyakarta, Surabaya, Mataram, Pontianak, Tanjung Selor, Palangkaraya, Samarinda, Makassar, Palu, Kendari, Ambon, Ternate, Sorong, and Jayawijaya.Meanwhile, cloudy conditions are expected to cover Denpasar, Kupang, Manado, Manokwari, and Jayapura.In addition to the potential rain, BMKG also reminded the public, especially fishermen and shipping actors, to be aware of high waves in a number of North Sumatra waters on November 13-15, 2026.BMKG Praktirawan of the Belawan Maritime Meteorology Station, Christen Marpaung, said high waves could potentially occur in the waters west of the Nias Islands, the western Indian Ocean of the Nias Islands, and the waters west of the Batu Islands."Be aware of high waves in a number of waters in North Sumatra that can occur on November 13 to 15, 2026," said Christen in Medan, Thursday, November 12.He explained that the potential for high waves was influenced by the active spatial phenomenon of the Madden-Julian Oscillation (MJO) in the western Indian Ocean of Sumatra. This condition is also supported by the Rossby Equatorial wave, the turning area of the wind, and the convergence that can trigger convective activity in the North Sumatra region (Sumbagut).BMKG urges the public to pay attention to the development of weather information and early warnings, especially for fishermen and users of marine transportation activities in areas of potentially high waves.