Rainfall

For March 2023, above-normal rainfall is predicted over much of the northern half of the Maritime Continent, with highest likelihood over the Philippines, based on the multi-model ensemble (Figure 4). Below-normal rainfall is predicted over the western half of Borneo by all three models (Figures 1-3), with the NCEP and ECMWF models also predicting below-normal rainfall over parts of the southwestern Maritime Continent. The models’ skill is moderate to good for northern Maritime Continent for above-normal tercile category and low to moderate for central Borneo and the southwestern Maritime Continent for below-normal tercile category.

For Mainland Southeast Asia, based on the multi-model ensemble (Figure 4), there is an increase in chance of above-normal rainfall over the central and southeastern regions, with the ECMWF model predicting the largest extent of above-normal rainfall, followed by the NCEP model and then the UK Met Office with the smallest region of above-normal rainfall predicted. Elsewhere in Mainland Southeast Asia, models predict either below-normal rainfall or no dominant tercile. The models’ skill is generally low over much of Mainland Southeast Asia at this time of the year.