Rainfall

For March 2022, above-normal rainfall is predicted over much of the Maritime Continent apart from the equatorial region, as seen in the multi-model ensemble (Figure 4). For the equatorial region, while the NCEP model (Figure 1) predicts above-normal rainfall over Sumatra and no dominant tercile for southern Borneo, the ECMWF model (Figure 2) predicts below-normal rainfall, and the UK Met Office model (Figure 3) predicts a mixture of no dominant and below-normal rainfall for the region. The models’ skill is moderate to relatively good for northern half of the Maritime continent, and low to moderate for the southern half. 

Over Mainland Southeast Asia, all three models predict an increased chance of above-normal rainfall for much of the region, with the NCEP model having the highest confidence. ECMWF predicts a mix of no dominant and above-normal rainfall over the region, while UK Met Office model predicts above-normal rainfall with a region of below-normal rainfall over parts of eastern Mainland Southeast Asia. While there is reasonable agreement among the models for above-normal rainfall for much of Mainland Southeast Asia, as this is the dry time of the year, any increase in rainfall is not expected to be large (see Figure 6 for the above-normal rainfall climatological threshold). The models’ skill is also generally low to moderate for Mainland Southeast Asia for this time of the year.