Rainfall
Monthly Rainfall Outlook: September 2022
Issued: 30 Aug 2022
For September 2022, models predict above-normal rainfall over much of the southern ASEAN region.
For September 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 high 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, no dominant tercile is predicted (Figure 4). While the NCEP model predicts an increased chance of above-normal rainfall for much of the region (Figure 1) the ECMWF and UK Met Office models show a mix of below- to-above normal rainfall (Figures 2 and 3, respectively). The models’ skill for all three terciles is low for most of the northern ASEAN region, although it is low to moderate for the Philippines.
Figure 1: Rainfall tercile summary predictions of NCEP model for September 2022 (contains modified Copernicus C3S information).
Figure 2: Rainfall tercile summary predictions of ECMWF model for September 2022 (contains modified Copernicus C3S information).
Figure 3: Rainfall tercile summary predictions of UK Met Office model for September 2022 (contains modified Copernicus C3S information).
Figure 4: Rainfall tercile summary predictions of the multi-model ensemble for September 2022 (contains modified Copernicus C3S information).
Figure 5: Average climatological rainfall's lower tercile boundary for September based on CHIRPS (Reference period: 1991-2020).
Figure 6: Average climatological rainfall's upper tercile boundary for September 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.