The La Nina climate anomaly has been observed to continue in the Pacific Ocean with a “moderate” level of intensity. The sea surface temperature of the central Pacific Ocean in the Nino 3.4 area shows an anomaly of -1.4 degree Celsius.
So the current development shows moderate La Nina intensity which is predicted to peak in the period January – March 2021, and then will weaken in May 2021. According to the Deputy for Climatology of the Meteorological Climatology and Geophysics Agency, Herizal, through his press release, Tuesday, December 8, the season Rainfall in most parts of Indonesia is predicted to last until April 2021.
Increased vigilance is needed in areas that are predicted to receive rainfall accumulation with the criteria High to very high (> 300mm / month) in December 2020 – January 2021. Among them are likely to occur on the west coast of Sumatra, most of the island of Java, Bali, parts of Nusa Tenggara. West, parts of East Nusa Tenggara, parts of western and central Kalimantan, Sulawesi, parts of Maluku, parts of West Papua and Papua.
“The peak of the 2020/2021 rainy season is predicted for most regions to occur in January – February 2021 which generally coincides with the peak of the Asian monsoon,” he said.
Against the background of the La Nina climate anomaly, the increased activity of the Asian Monsoon in December can also be accompanied by several other special atmospheric phenomena such as cold surges, equatorial atmospheric waves (MJO) and inter-tropical air mass confluence (Inter Tropical Convergence Zone – ITCZ). These phenomena have been known to occur simultaneously or independently and are capable of triggering extreme rainfall which has a significant impact, which is predicted to occur in the last week period of December 2020 – January 2021.
The results of monitoring the development of the rainy season until the end of November 2020 show that as many as 61% of areas in Indonesia have entered the rainy season, which includes most of Aceh, North Sumatra, most of Riau, West Sumatra, Jambi, Jakarta, most of West Java, Central Java, Special Region of Yogyakarta, part of East Java, part of Bali, part of West Nusa Tenggara, northern Flores, Kalimantan, part of North Sulawesi, Gorontalo, Central Sulawesi, West Sulawesi, western part of South Sulawesi, North Maluku, part of Maluku, West Papua and Papua the northern part.
The Meteorology, Climatology and Geophysics Agency (Meteorology, Climatology and Geophysics) urges related parties in the Central Government and Regional Governments or people living in areas that have the potential to get high to very high rainfall to be aware of the threat of hydrometeorological disasters such as floods, landslides and flash floods, and to be asked to continue to monitor information weather developments and early warning from the Meteorology, Climatology and Geophysics Agency.