Rainfall

For NDJ 2023-2024, below-normal rainfall is predicted for the southern and eastern Maritime Continent while above-normal rainfall is predicted for the northwestern Maritime Continent, based on the multi-model ensemble (Figure 4). The ECMWF model (Figure 2) shows the highest confidence for below-normal rainfall for the southern Maritime Continent, while the NCEP and UK Met Office models (Figures 1 and 3) show high confidence over the southwestern region. All three models predict an increase in chance of above-normal rainfall over the northwestern Maritime Continent, although with lower confidence compared to the below-normal rainfall predicted. Models’ skill is moderate to good skill for below-normal rainfall over the southern and eastern Maritime Continent, and low to moderate for above-normal rainfall over the northwestern Maritime Continent.

For Mainland Southeast Asia, there is a small increase in chance of above-normal rainfall over much of the region, based on the multi-model ensemble (Figure 4). While all three models agree on an increase in chance of above-normal rainfall over central Mainland Southeast Asia, the NCEP and UK Met Office models (Figures 1 and 3) predict below-normal rainfall over parts of Myanmar, and the ECMWF and UK Met Office models (Figures 2 and 3) predict near-normal rainfall over southeastern Mainland Southeast Asia. However, it is the dry season for the region, and the models’ skill is generally low over Mainland Southeast Asia for the predicted tercile categories.