Rainfall
Monthly Rainfall Outlook: October 2022
Issued: 30 Sep 2022
For October 2022, models predict above-normal rainfall over much of the ASEAN region.
For October 2022, above-normal rainfall is predicted over much of the southern ASEAN region, with highest likelihood over southern Maritime Continent (Figure 4). The exception is over parts of the western Maritime Continent where overall an increased chance of below-normal rainfall is predicted. The models’ skill is moderate to good for above-normal rainfall over most of the southern ASEAN region, apart from over the western Maritime Continent where the models’ skill is low.
For the northern ASEAN region, above-normal rainfall is predicted (Figure 4) but with relatively lower likelihood than the southern ASEAN region. While the UK Met Office model predicts an increased chance of above-normal rainfall for much of the region (Figure 3), the ECMWF and NCEP models show near- to above-normal rainfall for much of the region (Figures 1 and 2, respectively). The models’ skill is low for most of the northern ASEAN region, although it is low to moderate for the eastern half of the northern ASEAN region.

Figure 1: Rainfall tercile summary predictions of NCEP model for October 2022 (contains modified Copernicus C3S information).

Figure 2: Rainfall tercile summary predictions of ECMWF model for October 2022 (contains modified Copernicus C3S information).

Figure 3: Rainfall tercile summary predictions of UK Met Office model for October 2022 (contains modified Copernicus C3S information).

Figure 4: Rainfall tercile summary predictions of the multi-model ensemble for October 2022 (contains modified Copernicus C3S information).

Figure 5: Average climatological rainfall's lower tercile boundary for October based on CHIRPS (Reference period: 1991-2020).

Figure 6: Average climatological rainfall's upper tercile boundary for October 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.