Rainfall
Monthly Rainfall Outlook: May 2023
Issued: 29 Apr 2023
For May 2023, models predict below-normal rainfall over much of the southern ASEAN region.
For May 2023, below-normal rainfall is predicted over much of the southern ASEAN region, based on the multi-model ensemble (Figure 4). The NCEP and UK Met Office models (Figure 1 and 2) predicts an increased chance of below-normal rainfall over most of the southern ASEAN region, while the ECMWF model confines the increased chance of below-normal rainfall over the southwestern Maritime Continent. The models’ skill is generally low to moderate for above-normal rainfall over the southern ASEAN region.
For the northern ASEAN region, 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 moderate for much of the northern ASEAN region at this time of year.
Figure 1: Rainfall tercile summary predictions of NCEP model for May 2023 (contains modified Copernicus C3S information).
Figure 2: Rainfall tercile summary predictions of ECMWF model for May 2023 (contains modified Copernicus C3S information).
Figure 3: Rainfall tercile summary predictions of UK Met Office model for May 2023 (contains modified Copernicus C3S information).
Figure 4: Rainfall tercile summary predictions of the multi-model ensemble for May 2023 (contains modified Copernicus C3S information).
Figure 5: Average climatological rainfall's lower tercile boundary for May based on CHIRPS (Reference period: 1991-2020).
Figure 6: Average climatological rainfall's upper tercile boundary for May 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.