The Meteorology, Climatology, and Geophysics Agency (BMKG) has\nexplained the potential for rain during the onset of the dry season.\nBMKG noted that the activity of tropical cyclone seed 99W and\natmospheric waves at the start of the dry season has triggered\nsignificant weather potential in parts of Indonesia.<\/p>\n
BMKG\u2019s Public Meteorology Director, Andri Ramdhani, explained that\ncurrent climate analysis shows some regions of Indonesia have entered\nthe dry season, while others are in a transitional period. This is\nindicated by minimal cloud cover from morning to midday, leading to\nintense surface heating.<\/p>\n
\u201cThis has led to maximum temperatures exceeding 35.0\u00b0C in Aceh, Riau,\nBali, most of Kalimantan, Central Sulawesi, West Papua, and East Java\nbetween 21 and 24 May 2026. In regions still in transition, daytime heat\naccumulation causes convection, leading to atmospheric instability and\nrain clouds forming in the afternoon and evening,\u201d Andri stated in a\nreport on Wednesday, 27 May 2026.<\/p>\n
Andri said the atmospheric instability is validated by high rainfall\nintensity, ranging from heavy to very heavy, recorded in parts of\nIndonesia, including West Kalimantan (129.5 mm\/day), Jakarta (102.4\nmm\/day), Bengkulu (96.4 mm\/day), Maluku (88.4 mm\/day), West Java (86.9\nmm\/day), Bangka Belitung Islands (77.7 mm\/day), Central Kalimantan (73.3\nmm\/day), North Sumatra (70.2 mm\/day), East Kalimantan (68.8 mm\/day),\nCentral Papua (67.2 mm\/day), North Sulawesi (64.5 mm\/day), Jambi (61.8\nmm\/day), Banten (58.6 mm\/day), South Sulawesi (55.6 mm\/day), Lampung\n(55.4 mm\/day), Southeast Sulawesi (55.2 mm\/day), North Kalimantan (52.2\nmm\/day), and Central Java (50.0 mm\/day).<\/p>\n
Andri added that the increased rainfall during this period is also\ninfluenced by interactions of several atmospheric phenomena.<\/p>\n
\u201cThe Madden-Julian Oscillation (MJO) is currently in phase 5\n(Maritime Continent). Additionally, Equatorial Rossby waves and Kelvin\nwaves are contributing to the growth of rain clouds in several\nIndonesian regions,\u201d he said.<\/p>\n
The formation of cyclonic circulation in several Indonesian regions\nhas also triggered areas of wind speed reduction (convergence). Such\natmospheric conditions further support cloud formation, increasing the\nlikelihood of rain in some areas.<\/p>\n
Atmospheric Dynamics Over the Coming Week<\/p>\n
Current global climate indicators show signs of El Ni\u00f1o conditions in\nthe Pacific Ocean, confirmed by a Nino 3.4 index of +0.68 and a Southern\nOscillation Index (SOI) of -12.5. However, regional atmospheric dynamics\nstill have the potential to trigger rain cloud growth, particularly in\nnorthern Indonesia.<\/p>\n
Tropical cyclone seed 99W is forecast to be located in the northern\nPacific Ocean near Papua New Guinea. This system creates convergence and\nconfluence areas from West Papua to Cendrawasih Bay, along the western\ncoast of Southwest Papua, and around the system. Additionally, cyclonic\ncirculation is predicted to form in the waters west of West Sumatra, the\nsouthwestern Indian Ocean off Banten, and the Sulu Sea. These systems\nform convergence and confluence areas in the waters west of Bengkulu,\nwest of North Sumatra, and around the cyclonic circulation.<\/p>\n
Furthermore, MJO activity projected towards phase 6 (Western Pacific)\nis expected to remain spatially active in North Kalimantan, East\nKalimantan, North Sulawesi, Gorontalo, Central Sulawesi, North Maluku,\nand northern West Papua and Southwest Papua. Easterly-moving Kelvin\nwaves are also forecast to be active across Aceh, northern West\nKalimantan, East Kalimantan, North Kalimantan, North Sulawesi,\nGorontalo, and Central Sulawesi.<\/p>\n
Meanwhile, westward-propagating Equatorial Rossby waves are forecast\nto be active in East Kalimantan, North Kalimantan, North Sulawesi,\nGorontalo, and Central Sulawesi. Mixed Rossby-Gravity (MRG) wave\nactivity is also expected in northern Aceh. MJO and atmospheric wave\nactivities will help increase moisture supply and support rain cloud\nformation in the affected regions.<\/p>\n
Rainfall Potential Over the Coming Week<\/p>\n
Andri said Indonesia\u2019s weather is generally dominated by light to\nheavy rain. During 26-28 May, he warned of moderate rainfall increases\nin Aceh, West Sumatra, Riau, Riau Islands, Jambi, South Sumatra, Bangka\nBelitung Islands, Bengkulu, Lampung, Banten, Central Java, East Java,\nWest Kalimantan, Central Kalimantan, East Kalimantan, South Kalimantan,\nNorth Sulawesi, Gorontalo, Central Sulawesi, West Sulawesi, South\nSulawesi, Southeast Sulawesi, Maluku, Southwest Papua, West Papua,\nCentral Papua, Papua, and South Papua.<\/p>\n
Additionally, heavy rain accompanied by lightning, thunderstorms, and\nstrong winds may occur with the following early warning levels:<\/p>\n
\u2022 Caution (heavy to very heavy rain): North Kalimantan, North Maluku,\nand Mountainous Papua.<\/p>\n
\u2022 Strong winds: Aceh, East Java, East Kalimantan, West Nusa Tenggara,\nEast Nusa Tenggara, Maluku, North Maluku, Southwest Papua, West Papua,\nSouth Papua.<\/p>\n
For the period 29 May to 1 June, moderate rainfall increases are\nexpected in Aceh, Riau, Riau Islands, East Java, West Kalimantan, North\nKalimantan, North Sulawesi, Central Sulawesi, West Sulawesi, South\nSulawesi, Southeast Sulawesi, North Maluku, Maluku, Southwest Papua,\nCentral Papua, Papua, and South Papua.<\/p>\n
Heavy rain accompanied by lightning, thunderstorms, and strong winds\nmay occur with the following early warning levels and<\/p>", "url": "https:\/\/jawawa.id\/newsitem\/heavy-rain-persists-as-dry-season-begins-in-may-bmkg-explains-1779899986", "image": "" }, "sponsor": "Okusi Associates", "sponsor_url": "https:\/\/okusiassociates.com" }