Rainfall

Seasonal Rainfall Outlook: August-October 2020 (ASO)

Issued: 30 Jul 2020

For ASO 2020, above-normal rainfall is predicted for much of the Maritime Continent, as well as coastal regions of southern Mainland Southeast Asia.

For ASO 2020, all three models – NCEP, ECMWF, and UK Met Office (Figures 1-3) – predict an increased chance of above-normal rainfall over the Maritime Continent (apart from Sumatra, Peninsular Malaysia and the Philippines where there is disagreement between the models) and coastal regions of southern Mainland Southeast Asia.

The model skill is moderate to high for most parts of the Maritime Continent, but low for the coastal regions of southern Mainland Southeast Asia and the three regions of the Maritime Continent where the models disagree. Elsewhere, the models show inconsistent forecasts or have low skill.

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Figure 1: Rainfall tercile summary predictions of NCEP model for ASO 2020.
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Figure 2: Rainfall tercile summary predictions of ECMWF model for ASO 2020 (contains modified Copernicus C3S information).
The qualitative outlook is assessed for the region in general. For specific updates on the national scale, the relevant ASEAN National Meteorological and Hydrological Services should be consulted.