TEMPO.CO, Jakarta – Even rainy weather in the Jabodetabek (Greater Jakarta) area, which occurred on Saturday afternoon to the evening of November 2, 2024, is likely to persist for the next few days. Rain is triggered by the fairly steady growth of rain clouds of light to moderate intensity.

“From the afternoon to the evening, even approaching night time,” said the director of public meteorology BMKGAndri Ramdhani, when contacted on Saturday evening.

According to Andri, widespread rain occurred in Jabodetabek following the departure of Tropical Cyclone Kong-Rey to the northwest. The air mass that was previously drawn close to the tropical cyclone system in the northern part of Indonesia is now actively increasing the atmospheric instability in the Indonesian region.

“As a result, convective and air mass lifting become more active, increasing the potential for the formation of rain clouds in some areas of Indonesia including the Jabodetabek region,” Andri said.

Andri added, another atmospheric dynamic that plays a role in increasing rainfall in the Jabodetabek region is the activity of equatorial Rossby waves passing through the Jakarta region. In addition, there is also support from potential humidity and high air instability, as well as the convergence or meeting of air around the Jakarta region.

Andri explained, the presence of tropical cyclone Kong-Rey in the waters north of the Philippines caused previously hot and dry weather in Indonesia. The cyclone attracts air masses around it, including in Indonesia, reducing the potential for rain cloud growth, especially in the southern part of Indonesia.

This condition was previously predicted not to last long as Kong-Rey moved towards the northwest-north, moving away from the Indonesian region, which no longer indirectly affects the temperature increase.

Not only in the Jabodetabek region, Andri conveyed, in the weekly weather outlook for the period October 31-November 6, 2024, the BMKG predicted that Sumatra, Java, Bali, Nusa Tenggara, Kalimantan and Sulawesi regions have the potential for rain in the afternoon to evening. The distribution of rain is not even and the duration is relatively short.

“This is common during the transition period and at the start of the rainy season, which is predicted to occur from early to late November,” he said.

Separate researcher at the Climate and Atmospheric Center of BRINErma Yulihastin, also warned of similar rainy weather today for the next 2-3 days. However, Erma has not indicated the start of the rainy season.

According to her, the triggering factor is the occurrence of wind shear patterns due to the activity of the storm line from Sumatra to Java. She mentioned that wind shear has the potential to trigger the formation of extreme weather phenomena of storms and potential strong winds. At the same time, the squall line is triggered by the formation of mesovortices in the Indian Ocean near the west coast of Lampung.

“The surge line extending from sea to land also contributes to bringing rain from the Indian Ocean to the western part of Java,” she said.

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