Rainfall
Monthly Rainfall Outlook: December 2023
Issued: 30 Nov 2023
For December 2023, below-normal rainfall is predicted over the southern and eastern Maritime Continent. Above-normal rainfall is predicted around the Malay Peninsula and over parts of Borneo.
For December 2023, below-normal rainfall is predicted over the southern and southeastern Maritime Continent, with highest likelihood over the southwestern Maritime Continent based on the multi-model ensemble (Figure 4). The NCEP model (Figure 1) shows the highest confidence for below-normal rainfall, followed by the ECMWF and the UK Met Office models (Figures 2 and 3). Models’ skill is moderate to good skill for below-normal rainfall over the mentioned regions.
Above-normal rainfall is predicted over central and eastern Mainland Southeast Asia (Figure 4). However, it is the dry season for Mainland Southeast Asia. Above-normal rainfall is also predicted around the Malay Peninsula and over parts of Borneo, based on the multi-model ensemble (Figure 4). The UK Met Office model (Figure 3) has the largest extent and confidence of above-normal rainfall, followed by the ECMWF model (Figure 2) and the NCEP model (Figure 1). Models’ skill for above-normal rainfall is low to moderate for mentioned regions.
Figure 1: Rainfall tercile summary predictions of NCEP model for December 2023 (contains modified Copernicus C3S information).
Figure 2: Rainfall tercile summary predictions of ECMWF model for December 2023 (contains modified Copernicus C3S information).
Figure 3: Rainfall tercile summary predictions of UK Met Office model for December 2023 (contains modified Copernicus C3S information).
Figure 4: Rainfall tercile summary predictions of the multi-model ensemble for December 2023 (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.