Rainfall
Monthly Rainfall Outlook: December 2022
Issued: 30 Nov 2022
For December 2022, models predict above-normal rainfall over much of the eastern Maritime Continent and coastal southeastern Mainland Southeast Asia.
For December 2022, above-normal rainfall is predicted over much of the eastern Maritime Continent, with highest likelihood over the Philippines, based on the multi-model ensemble (Figure 4). Below-normal rainfall is also predicted over central Borneo by all three models (Figures 1-3). The models’ skill is moderate to relatively high for eastern Maritime Continent and central Borneo for their respective tercile categories. Elsewhere in the Maritime Continent, the models’ skill is low.
For Mainland Southeast Asia, based on the multi-model ensemble (Figure 4), there is an increase in chance of above-normal rainfall over the coastal southeastern region and below-normal rainfall over parts of the northern region. Elsewhere, there is either no dominant tercile predicted or disagreement between the models. The models’ skill is generally low to moderate for Mainland Southeast Asia, with moderate skill over southeastern parts.
Figure 1: Rainfall tercile summary predictions of NCEP model for December 2022 (contains modified Copernicus C3S information).
Figure 2: Rainfall tercile summary predictions of ECMWF model for December 2022 (contains modified Copernicus C3S information).
Figure 3: Rainfall tercile summary predictions of UK Met Office model for December 2022 (contains modified Copernicus C3S information).
Figure 4: Rainfall tercile summary predictions of the multi-model ensemble for December 2022 (contains modified Copernicus C3S information).
Figure 5: Average climatological rainfall's lower tercile boundary for December based on CHIRPS (Reference period: 1991-2020).
Figure 6: Average climatological rainfall's upper tercile boundary for December based on CHIRPS (Reference period: 1991-2020).
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.