The Meteorology, Climatology and Geophysics Agency issued early warnings for heavy rain accompanied by lightning in several major cities on Sunday.
BMKG forecaster Vita urged residents in affected areas to increase preparedness against secondary impacts such as floods and landslides. Potential thunder rain needs to be watched in Pekanbaru and Tanjung Selor.
The agency also called for vigilance in North Sumatra, West Sumatra, and South Sulawesi provinces due to the potential for heavy to very heavy rain. Convergence zones were observed stretching from Aceh to Papua.
In other western areas moderate to light rain is forecast in Padang, Medan, Tanjung Pinang, Bengkulu, Palembang, and Pontianak. Eastern regions such as Makassar and Jayapura are predicted to be mostly cloudy.