Jamaah, Usep Adi Wihanda, Jakarta – After enduring scorching heat with temperatures reaching up to 37.6 degrees Celsius in recent days, parts of Indonesia are now preparing for a wave of heavy rains, thunderstorms, and strong winds, according to the Meteorology, Climatology, and Geophysics Agency (BMKG).
The heatwave, which affected Java, Bali, West and East Nusa Tenggara, as well as southern parts of Kalimantan and Papua, was caused primarily by the sun's apparent movement south of the equator, said BMKG weather forecaster Iqbal Fathoni on Saturday.
"The main factor is the apparent solar motion. Around September 23, the sun was directly above the equator. By October, it starts shifting southward," Iqbal told Beritasatu.com at BMKG headquarters in Jakarta. "This equatorial wave movement increases surface temperatures in regions like Java, Bali, and Nusa Tenggara."
He added that reduced cloud cover has allowed more direct sunlight to heat the land, while dry and hot winds from the Australian continent have further intensified the high temperatures.
Iqbal urged the public to remain cautious, especially when engaging in outdoor activities. "Stay well hydrated and limit outdoor exposure, particularly from morning to midday," he advised.
However, BMKG warned that the transition period from the dry to rainy season will bring its own hazards. The agency has detected the arrival of the Rossby Equatorial Wave and the Madden-Julian Oscillation (MJO) over parts of Java, two atmospheric phenomena that are likely to increase rainfall in the coming days.
"The combination of these two patterns can enhance rain intensity, especially across parts of Java," Iqbal said, adding that showers accompanied by lightning and strong winds could occur in the late afternoon or evening.
The onset of heavier rain has already triggered several weather-related disasters across the country. In West Java, a provincial road connecting Bandung, Sumedang, and Subang was blocked by a landslide late Friday night. The collapse of a six-meter retaining wall buried the road under rocks and mud, halting traffic for hours. No casualties were reported, though authorities said poor construction quality and heavy rain likely caused the collapse.
In Central Java, powerful winds tore through several villages in Semarang and Grobogan regencies on Friday afternoon. In Semarang's Suruh district, at least ten homes and several public facilities were severely damaged across four villages. Fallen trees knocked down power lines and crushed rooftops, while a historic building and several wedding tents were flattened.
In Grobogan, strong winds destroyed or damaged hundreds of homes and toppled trees across four villages in Gabus and Tegowanu districts. Residents, assisted by military personnel, disaster relief officers, and local volunteers, began clearing debris and repairing damaged structures on Saturday.
Source: https://jakartaglobe.id/tech/from-heatwave-to-heavy-rain-bmkg-warns-of-sudden-weather-change