Tropical Cyclone 90S Looms Off Southern Java; East Java Enters Red Zone for Very Heavy Rain on Wednesday 4 March 2026

Surabaya — The Indonesian Meteorology, Climatology, and Geophysics Agency (BMKG) Juanda has issued an early warning of extreme weather forecast to affect almost the entire East Java region on Wednesday, 4 March 2026. According to the latest weather modelling, East Java is now on ALERT for potential impacts from heavy to very heavy rainfall.

Head of BMKG Juanda, Taufiq Hermawan, explained that the conditions are triggered by unstable atmospheric dynamics, including the activity of Tropical Cyclone 90S in the Indian Ocean south of Central Java. In addition, disturbances from the Madden-Julian Oscillation (MJO) and Rossby waves are accelerating the growth of large convective clouds.

BMKG urged residents across 38 regencies/cities to stay vigilant, focusing on the combination of extremely heavy rain and strong winds that could trigger hydrometeorological disasters. ‘We ask the public to monitor cloud movement regularly via the Info BMKG app and avoid outdoor activities when dark thunderclouds gather,’ said Taufiq.

Drivers travelling along mountainous routes such as Payung (Batu) or the southern cross route should exercise extra caution due to reduced visibility and slick roads. Port authorities have been asked to monitor high waves in the southern Java Sea, which may rise under the influence of Tropical Cyclone 90S.