Rainfall
Monthly Rainfall Outlook: April 2023
Issued: 30 Mar 2023
For April 2023, models predict below-normal rainfall over the southwestern and central Maritime Continent and above-normal rainfall for parts of the northeastern Maritime Continent.
For April 2023, below-normal rainfall is predicted over the southwestern and central Maritime Continent whereas above-normal rainfall is predicted over parts of the northeastern Maritime Continent, based on the multi-model ensemble (Figure 4). The NCEP and ECMWF models (Figures 1 and 2) have higher confidence in below-normal rainfall over parts of the western and central Maritime Continent, while the UK Met Office model has the highest confidence of above-normal rainfall over the northeastern region. The models’ skill is generally low for below-normal rainfall for southwestern Maritime Continent and low to moderate for above-normal rainfall over the northeastern Maritime Continent.
For Mainland Southeast Asia, there is no dominant tercile predicted based on the multi-model ensemble and the individual models show disagreement on the tercile category. The models’ skill is generally low for much of the Mainland Southeast Asia.
Figure 1: Rainfall tercile summary predictions of NCEP model for April 2023 (contains modified Copernicus C3S information).
Figure 2: Rainfall tercile summary predictions of ECMWF model for April 2023 (contains modified Copernicus C3S information).
Figure 3: Rainfall tercile summary predictions of UK Met Office model for April 2023 (contains modified Copernicus C3S information).
Figure 4: Rainfall tercile summary predictions of the multi-model ensemble for April 2023 (contains modified Copernicus C3S information).
Figure 5: Average climatological rainfall's lower tercile boundary for April based on CHIRPS (Reference period: 1991-2020).
Figure 6: Average climatological rainfall's upper tercile boundary for April 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.