Rainfall
Monthly Rainfall Outlook: January 2023
Issued: 28 Dec 2022
For January 2023, models predict above-normal rainfall over much of the northern Maritime Continent, Malay Peninsula, and southeastern Mainland Southeast Asia.
For January 2023, above-normal rainfall is predicted over much of the northern Maritime Continent and Malay Peninsula, 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 good for northern Maritime Continent for above-normal tercile category and low for central Borneo for below-normal tercile category. 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. Below-normal rainfall is also predicted over parts of the northern Mainland Southeast Asia. Elsewhere, there is either no dominant tercile predicted or disagreement between the models. The models’ skill is generally low over much of Mainland Southeast Asia, with moderate skill over the southeastern parts.
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. Below-normal rainfall is also predicted over parts of the northern Mainland Southeast Asia. Elsewhere, there is either no dominant tercile predicted or disagreement between the models. The models’ skill is generally low over much of Mainland Southeast Asia, with moderate skill over the southeastern parts.
Figure 1: Rainfall tercile summary predictions of NCEP model for January 2023 (contains modified Copernicus C3S information).
Figure 2: Rainfall tercile summary predictions of ECMWF model for January 2023 (contains modified Copernicus C3S information).
Figure 3: Rainfall tercile summary predictions of UK Met Office model for January 2023 (contains modified Copernicus C3S information).
Figure 4: Rainfall tercile summary predictions of the multi-model ensemble for January 2023 (contains modified Copernicus C3S information).
Figure 5: Average climatological rainfall's lower tercile boundary for January based on CHIRPS (Reference period: 1991-2020).
Figure 6: Average climatological rainfall's upper tercile boundary for January 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.