Figure 1: 1-month SPI for December 2023 (reference period, 1991-2020)
Figure 2: SSTA across the Pacific and Indian Ocean for December 2023 (reference climatology, 1991-2020, JMA-iTacs)
Areas of Concern: Indonesia and Philippines
The sea surface temperatures (SSTs) across the tropical Pacific continued to be warmer than average in December as it further strengthened and may likely have reached or reaching its peak. The strong warming was observed almost over all Niño regions. Moreover, the SSTAs in the western Pacific and over most of the maritime continent were near to slightly above average, particularly around the Philippines and Indonesia.
Strong positive IOD values were still observed during the month, as warmer than average SSTs were observed over the western equatorial Indian Ocean while the eastern equatorial Indian Ocean was cooler than average.
Inactive phase of the Madden–Julian Oscillation (MJO) in December was observed characterized by suppressed convection and precipitation in the region.