Rainfall
Seasonal Rainfall Outlook: September-November 2019 (SON)
Issued: 30 Aug 2019
For SON 2019, below-normal rainfall is favoured over most parts of the Maritime Continent. Some parts of northern Southeast Asia (southern parts of Myanmar and Thailand) are predicted to have increased chances of above-normal rainfall.
For SON 2019, all three models – NCEP CFSv2, ECMWF and the UK Met Office (Figures 1-3) predict below-normal rainfall over for most parts of the Maritime Continent, except for parts of the Philippines and northern Sumatra. The probability for below-normal category does vary between the models, with the ECMWF (Figure 2) and NCEP (Figure 1) models showing a higher probability of below-normal rainfall than the UK Met Office (Figure 3) models. Overall, the models’ skill scores for rainfall are relatively good over the Maritime Continent except for northern parts of Borneo and Sumatra, as well as Peninsular Malaysia.
There is no consistent prediction for much of northern Southeast Asia, although there is increased likelihood for above-normal rainfall for select regions (e.g. southern coastal parts of Myanmar and Thailand). Models’ skill scores for this region are also generally low for the SON season.
Figure 1: Rainfall tercile summary predictions of NCEP model for SON 2019.
Figure 2: Rainfall tercile summary predictions of ECMWF model for SON 2019 (contains modified Copernicus C3S information).