Rainfall
Seasonal Rainfall Outlook: July-September 2020 (JAS)
Issued: 29 Jun 2020
For JAS 2020, above-normal rainfall is predicted for regions over the Maritime Continent, particularly over parts of Sumatra, Borneo, Java, Sulawesi, and Papua.
For JAS 2020, all three models – NCEP CFSv2, ECMWF, and UK Met Office (Figures 1-3) – predict an increased chance of above-normal rainfall over the equatorial region of Southeast Asia (between 10°N and 10°S), with good agreement across models over parts of Sumatra, Borneo, Java, Sulawesi, and Papua.
The model skill is moderate to high for most parts of this region, except for northern Sumatra. Elsewhere, the models show inconsistent forecasts or have low skill.
Figure 1: Rainfall tercile summary predictions of NCEP model for JAS 2020.
Figure 2: Rainfall tercile summary predictions of ECMWF model for JAS 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.