Rainfall
Monthly Rainfall Outlook: July 2021
Issued: 30 Jun 2021
For July 2021, there is a small increase in chance of above-normal rainfall over much of the equatorial region, in particular for the area over central and eastern parts of the Maritime Continent.
For July 2021, based on the multi-model ensemble there is a small increase in chance of above-normal rainfall over much of the equatorial region, in particular for the area over central and eastern parts of the Maritime Continent (Figure 4). The ECMWF and UK Met Office models (Figures 2 and 3) predict a larger region with above-normal rainfall than the NCEP model (Figure 1), with the ECMWF model spanning the equatorial band from 5°N to 10°S and the UK Met Office model predicting the increased chance of above-normal rainfall conditions further southwards from 2°S to 10°S. The NCEP model only predicts parts of southern Sumatra and Java to experience above-normal rainfall conditions. The models’ skill is moderate to relatively high for the central and eastern parts of the Maritime Continent.
Elsewhere in western Maritime Continent, Mainland Southeast Asia and the Philippines, there is either no dominant tercile predicted or the models’ skill is low.
Figure 1: Rainfall tercile summary predictions of NCEP model for July 2021.
Figure 2: Rainfall tercile summary predictions of ECMWF model for July 2021 (contains modified Copernicus C3S information).
Figure 3: Rainfall tercile summary predictions of UK Met Office model for July 2021 (contains modified Copernicus C3S information).
Figure 4: Rainfall tercile summary predictions of the multi-model ensemble for July 2021 (contains modified Copernicus C3S information).
Figure 5: Average climatological rainfall's lower tercile boundary for July based on CHIRPS (Reference period: 1991-2020).
Figure 6: Average climatological rainfall's upper tercile boundary for July 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.