Equatorial Waves and Cyclone Seeds Trigger Extreme Weather in Indonesia

Apart from heavy rain and high waves, a number of coasts have the potential to be hit by tidal floods.

The following article was translated using both Microsoft Azure Open AI and Google Translation AI. The original article can be found in Gelombang Ekuatorial dan Bibit Siklon Memicu Cuaca Ekstrem di Indonesia

KOMPAS/ISMAIL ZAKARIA

A high wave hit the area of Ampenan Beach, Mataram City, West Nusa Tenggara on Wednesday (13/3/2024). The Meteorology, Climatology, and Geophysics Agency's Zainudin Abdul Madjid Meteorology Station is urging the public to be aware of the potential for extreme weather, such as heavy rain accompanied by thunderstorms and strong winds, as well as high waves in NTB during the period of March 10-16, 2024.

JAKARTA, KOMPAS — Extreme weather that hit Indonesia was triggered by the activity of a number of equatorial waves and the emergence of two cyclone seeds in the Indian Ocean. Apart from heavy rain and high waves, a number of coasts have the potential to be hit by floods rob.

Deputy for Meteorology at the Meteorology, Climatology and Geophysics Agency (BMKG) Guswanto, in Jakarta, Thursday (14/3/2024), said that the Equatorial Rossby wave propagating westward occurred in the Indian Ocean west of Aceh to Bengkulu. This has the potential to increase convective activity and the formation of cyclonic circulation patterns in the region.

Meanwhile, a Kelvin wave moving eastwards is occurring in the southern part of Papua and the northern Pacific Ocean adjacent to Papua, which has the potential to increase convective activity and the formation of cyclonic circulation patterns in the region.

Another factor is the presence of Madden-Julian Oscillation (MJO) waves which were observed on March 11, 2024 in quadrant 4 contributing to the formation of rain clouds in the Indonesian region. "The spatial presence of MJO has been observed to be active in almost all of Indonesia, except for the northern part of North Kalimantan, Papua, and Central Papua which have the potential to cause an increase in the growth of rain clouds in those areas," said Guswanto.

According to him, the combination of MJO, Kelvin waves, and Equatorial Rossby waves in the same region and time period occurs in the western Indian Ocean from Bengkulu to southern West Nusa Tenggara, Java-Bali, NTB, East Nusa Tenggara, Java Sea, Banda Sea, South and Southeast Sulawesi, North Maluku, South Papua, and Arafura Sea. This can increase convective activity and the formation of cyclonic circulation patterns in those areas.

Based on observations by BMKG, a tropical cyclone seed 91S emerged in the southeastern Indian Ocean of NTB. This system is forming a convergence zone and inducing an area of wind speed increase above 25 knots in the southern Indian Ocean of Java to NTB.

The tropical cyclone seedling 94S has also emerged in the Gulf of Carpentaria, Australia. This system forms a long convergence zone in the northern part of Australia and induces an area of wind speed increase above 25 knots from the Banda Sea and Timor Sea to the northern part of Australia and the southern Indian Ocean of NTT until the northern part of Australia.

Also read: Extreme Weather, Pekalongan and Semarang Hit by Floods

KOMPAS/P RADITYA MAHENDRA YASA

Floods inundated the northern coastal road, making it impassable for vehicles in Kaligawe, Semarang City, Central Java on Thursday, March 14, 2024. Bad weather in recent days caused the floods to paralyze public facilities and inundate residential areas.

Be alert and alert

Based on BMKG's rain forecast model, extreme rain can occur on March 14, 2024 in East Java, Bali, NTB, NTT, and Papua. For March 15, 2024, extreme rain is likely to hit NTB, NTT, and Papua.

Guswanto added that impact-based forecasts (IBF) show that there are a number of areas that are at the Alert and Alert level for extreme weather.

The regions classified as "Alert" for March 14th, 2024 include Lampung, Banten, DKI Jakarta, West Java, Central Java, East Java, DI Yogyakarta, Bali, NTB, NTT, Central Kalimantan, and Papua. Meanwhile, for March 15th, 2024, the "Alert" regions include Lampung, Banten, West Java, Central Java, East Java, DI Yogyakarta, Bali, NTB, NTT, Central Kalimantan, Maluku, and Papua.

Possible translation: The potential for tidal flooding could occur on the western coast of Banten, the southern coast of Banten and West Java, as well as the southern coast of East Java.

Regions categorized under extreme rainfall alert for March 14th, 2024 include Central Kalimantan and East Nusa Tenggara. Furthermore, on March 15th, 2024, it will be in effect in Central Kalimantan and East Nusa Tenggara as well.

"Impact-based forecasts (IBF) are forecast information that takes into account the potential impacts that will occur as a result of the weather," he said.

KOMPAS/P RADITYA MAHENDRA YASA

Residents walked out of their settlement to look for a safe location from the floodwaters in Kampung Sawah Besar, Semarang City, Central Java, on Thursday (14/3/2024).

The Head of the BMKG Maritime Center, Eko Prasetyo, also issued an early warning of high waves and potential flash floods that could occur until March 17, 2024. According to him, the cyclone seed 18S in southern West Java and low pressure in Southeast NTT have caused winds to move from the southwest to the northwest at a speed of 35 knots in some waters.

With these conditions, high waves of 2.5-4 meters can occur in the waters off the west of Lampung, the western Indian Ocean of Lampung, the western and southern parts of the Sunda Strait, south of Banten up to the island of Sumba, southern parts of the Bali-Badung-Lombok-Alas strait, the southern Indian Ocean of Banten up to West Java, as well as the Arafuru Sea. Meanwhile, waves as high as 4-6 meters potentially occur in the southern Indian Ocean of Central Java to East Java and the southern Indian Ocean of Bali to NTT.

Also read: Flood Impact, Daop 4 Semarang Cancels Four Train Trips

Eko also warned of the potential for tidal floods that could occur on the west coast of Banten, the south coast of Banten and West Java, and the south coast of East Java. "We urge the public to pay attention to the risk of high waves or swells on the coast which can cause rip currents or ocean reverse currents and increase the risk of activities around the coast. "We ask people who live and do activities in coastal areas around the coast where high waves are likely to occur to always be alert," he said.