Rainfall
Monthly Rainfall Outlook: June 2021
Issued: 31 May 2021
For June 2021, there is a small increase in chance of below-normal rainfall for parts of the equatorial region and a small increase in chance of above-normal rainfall for southwestern Mainland Southeast Asia.
For June 2021, based on the multi-model ensemble there is a small increase in chance of below-normal rainfall over parts of the equatorial region (Figure 4). The NCEP model (Figure 1) predicts below-normal rainfall over much of the equatorial region with higher confidence for Peninsular Malaysia, northern Sumatra, and western Borneo. The ECMWF model (Figure 2) predicts below- to near-normal rainfall, while the UK Met Office model (Figure 3) predicts a smaller portion of the equatorial region to receive below-normal rainfall. Elsewhere in the Maritime Continent, there is no dominant tercile or disagreement between the models. The models’ skill is low to moderate for the Maritime Continent.
For Mainland Southeast Asia, a small increase in chance of above-normal rainfall is predicted for southwestern Mainland Southeast Asia and Lao PDR. The models’ skill for these regions is low to moderate. Elsewhere in Mainland Southeast Asia, there is either no dominant tercile predicted or the models’ skill is low.
Figure 1: Rainfall tercile summary predictions of NCEP model for June 2021.
Figure 2: Rainfall tercile summary predictions of ECMWF model for June 2021 (contains modified Copernicus C3S information).
Figure 3: Rainfall tercile summary predictions of UK Met Office model for June 2021 (contains modified Copernicus C3S information).
Figure 4: Rainfall tercile summary predictions of the multi-model ensemble for June 2021 (contains modified Copernicus C3S information).
Figure 5: Average climatological rainfall's lower tercile boundary for June based on CHIRPS (Reference period: 1981-2010).
Figure 6: Average climatological rainfall's upper tercile boundary for June based on CHIRPS (Reference period: 1981-2010).
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.