Review of Regional Weather for February 2020
1.1 During February 2020, the region south of the equator predominately experienced above-average rainfall (Figure 1), with the largest positive anomalies (wetter conditions) over Java Island, Indonesia and southern Borneo. For north of the equator, above-average rainfall was observed over some coastal regions of Peninsular Malaysia while northern Borneo and most of the Philippines experienced below-average rainfall. The rainfall anomalies over mainland Southeast Asia were negligible, which is expected given that February is the drier time of the year for that region.
1.2 Overall, most of Southeast Asia experienced above-average temperature during February 2020 (Figure 2). The largest anomalies occurred over parts of Sulawesi, Papua and northern Viet Nam. As for the northern Southeast Asia, some parts of Cambodia, Thailand and Myanmar experienced below-average temperatures.
2. Climate Drivers
2.1 A Madden–Julian Oscillation (MJO) signal developed and strengthened over the Maritime Continent (Phases 4 and 5) during the first two weeks of February 2020 (Figure 3). The signal propagated eastwards with the main precipitation envelope reaching the western tip of Western Pacific (Phase 6). By the end of the second week, however, this MJO signal stalled, before weakening and becoming indiscernible in the third week of February. Broadly, Phases 4 and 5 normally bring wetter conditions for much of Southeast Asia in February, while Phase 6 brings a mixture of wetter and drier conditions.
2.2 The strong positive Indian Ocean Dipole (IOD) event from 2019, which had been weakening since November 2019, continued to weaken and returned to the neutral state in January 2020. The IOD typically remains in the neutral phase during the season from January to April.