Rainfall

For MAM 2023, based on the multi-model ensemble (Figure 4), there is an increased chance of above-normal rainfall for much of the northern half of the Maritime Continent with highest chance over the Philippines, while an increased chance of below-normal rainfall is predicted over much of the southern half of the Maritime Continent. There is some difference between the models in the extent of the below-normal predictions over the southern Maritime Continent. The NCEP model has the largest extent over most of the region (Figure 1), followed by the ECMWF model with below-normal predicted except for the eastern-most region (Figure 2), and the UK Met Office model predicting below-normal rainfall only for the western half of the region (Figure 3). The models’ skill is moderate to relatively good over the northern and southwest Maritime Continent, and low to moderate elsewhere.

For Mainland Southeast Asia, based on the multi-model ensemble (Figure 4), there is an increase in chance of above-normal rainfall for much of the central and eastern regions. The models’ skill for Mainland Southeast Asia is moderate to relatively good for the mentioned regions. Elsewhere in Mainland Southeast Asia, there is either no dominant tercile or model skill is low.