Jakarta. Indonesia’s meteorological agency on Friday warned of another week of extreme weather across the country, just days after Bali was hit by its most severe flooding in 10 years.

The Meteorology, Climatology, and Geophysics Agency (BMKG) said heavy rainfall and strong winds are likely to affect multiple provinces between Sept. 12–18, raising risks of floods, landslides, and high waves.

“The current atmospheric dynamics are triggering heavy to very heavy rainfall accompanied by strong winds that must be anticipated by both the public and local governments,” BMKG chief Dwikorita Karnawati said in Jakarta.

She pointed to a combination of climate drivers, including a negative Dipole Mode Index, negative Outgoing Longwave Radiation anomalies, the Madden–Julian Oscillation, and equatorial Kelvin and Rossby waves. A tropical cyclone seed identified as 93S in the Indian Ocean west of Bengkulu, as well as a cyclonic pattern over North Kalimantan, is further intensifying rain potential.

Between Sept. 12–14, heavy rainfall is forecast in Riau, Bangka Belitung, Lampung, Banten, Jakarta, West Java, Central Java, Yogyakarta, several parts of Kalimantan, Central Sulawesi, West Sulawesi, Maluku, and Papua. Strong winds are expected in the Riau Islands, South Sulawesi, and Maluku. From Sept. 15–18, the risk will shift to Central and East Java, West and South Sulawesi, and several Papuan provinces.

Bali’s Deadly Floods
The warning comes on the heels of devastating floods and landslides in Bali on Sept. 9–10, which the National Disaster Mitigation Agency (BNPB) described as the island’s worst hydrometeorological disaster in a decade.

More than 120 flood points were recorded across seven districts and cities, with Denpasar alone accounting for 81. Gianyar reported 14, Badung 12, Tabanan 8, while Karangasem, Jembrana, and Klungkung also faced severe inundation.

The death toll has risen to 18 as of Friday afternoon, while two people remain missing. The agency said at least 185 residents have been forced to evacuate their homes. Search and rescue agency Basarnas is continuing efforts to locate the missing victims.

BMKG data showed extreme daily rainfall drove the disaster. Jembrana recorded 385.5 millimeters in a single day, Tampaksiring 373.8 mm, Karangasem 316.6 mm, Klungkung 296 mm, and Abiansemal 284.6 mm. By climatological standards, rainfall above 150 mm per day is already considered extreme.

“The massive convective cloud formation was triggered by active Madden–Julian Oscillation, Kelvin, and Rossby waves combined with unstable local atmospheric conditions over Bali,” Dwikorita explained.

Environmental and Infrastructure Strain
BMKG also noted that inadequate drainage systems, sedimentation, clogged waterways, and land-use changes from green zones to residential and commercial areas worsened the flooding impact.

Despite having issued 11 early warnings during Sept. 9–10 alone, the scale of the downpour overwhelmed infrastructure capacity.

Dwikorita urged Indonesians to stay alert in the coming days and regularly monitor official BMKG updates via apps, social media, and television. She also called for preventive measures such as clearing drainage channels and avoiding littering to minimize flood risks.

“With preparedness and proper mitigation, we can reduce the risks from the extreme weather that will persist in the coming days,” she said.