Rainfall
Monthly Rainfall Outlook: June 2023
Issued: 31 May 2023
For June 2023, models predict below-normal rainfall over much of the southern ASEAN region.
For June 2023, below-normal rainfall is predicted over much of the southern ASEAN region, with highest likelihood over southern Maritime Continent based on the multi-model ensemble (Figure 4). The ECMWF model shows the highest confidence for below-normal rainfall over the southern Maritime Continent (Figure 2), followed by the UK Met Office (Figure 3). The NCEP model predicts below-normal rainfall for the equatorial region with no dominant tercile for much of the southern Maritime Continent (Figure 1). The skill is moderate to good for the southern ASEAN region for the ECMWF model and low to moderate for the NCEP and UK Met Office models.
For the northern ASEAN region, above-normal rainfall over coastal parts of western Mainland Southeast Asia is predicted based on the multi-model ensemble (Figure 4). There is either disagreement between the models or no dominant tercile predicted over the rest of Mainland Southeast Asia and much of the Philippines (Figure 1-3). The models’ skill for all three terciles is low for most of the northern ASEAN region, although it is low to moderate for coastal parts of western Mainland Southeast Asia and the Philippines.
Figure 1: Rainfall tercile summary predictions of NCEP model for June 2023 (contains modified Copernicus C3S information).
Figure 2: Rainfall tercile summary predictions of ECMWF model for June 2023 (contains modified Copernicus C3S information).
Figure 3: Rainfall tercile summary predictions of UK Met Office model for June 2023 (contains modified Copernicus C3S information).
Figure 4: Rainfall tercile summary predictions of the multi-model ensemble for June 2023 (contains modified Copernicus C3S information).
Figure 5: Average climatological rainfall's lower tercile boundary for June based on CHIRPS (Reference period: 1991-2020).
Figure 6: Average climatological rainfall's upper tercile boundary for June 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.