Rainfall
Seasonal Rainfall Outlook: March-May 2022 (MAM)
Issued: 28 Feb 2022
For MAM 2021, above-normal rainfall is predicted for much of the ASEAN region, apart from the equatorial region.
For MAM 2022, based on the multi-model ensemble (Figure 4), there is an increased chance of above-normal rainfall for much of the ASEAN region, apart from the equatorial region. The NCEP model (Figure 1) is most confident of above-normal rainfall over the northern ASEAN region compared to the ECMWF and UK Met Office models (Figures 2 and 3). All three models predict above-normal rainfall over much of the southern Maritime Continent, although the confidence is lower than for the northern ASEAN region, with the UK Met Office model predicting above-normal rainfall over Java, while the NCEP and ECMWF models indicate no dominant tercile over Java. Across the equator, there is disagreement between the three models.
Model skill is moderate to relatively good for southern Mainland Southeast Asia, Peninsular Malaysia, and the Philippines, and low to moderate for the rest of Southeast Asia.
Figure 1: Rainfall tercile summary predictions of NCEP model for MAM 2022.
Figure 2: Rainfall tercile summary predictions of ECMWF model for MAM 2022 (contains modified Copernicus C3S information).
Figure 5: Average climatological rainfall's lower tercile boundary for MAM based on CHIRPS (Reference period: 1991-2020).
Figure 6: Average climatological rainfall's upper tercile boundary for MAM 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.