Rainfall

Monthly Rainfall Outlook: December 2018

Issued: 30 Nov 2018

For December 2018, below-normal rainfall is favoured over much of the Philippines, while above normal rainfall is favoured over the western equatorial region. Elsewhere, climatological probabilities are generally predicted.

For December’s rainfall, all three models – NCEP CFSv2, ECMWF, and the UK Met Office (Figures 1-3) predict below-normal rainfall over much of the Philippines. For the southernmost part of the region, NCEP CFSv2 predicts below-normal rainfall over eastern Java and Sulawesi, with ECMWF and UK Met Office models shifting the below-normal rainfall further to the west, only covering Java. The disagreement between the models indicates a lower confidence in the below-normal rainfall for this region compared to over the Philippines.

For parts of Sumatra, southern Malay Peninsula and western Borneo, all three models predict an increase likelihood of above-normal rainfall, with the NCEP and the UK Met Office models indicating a higher probability compared to the ECMWF model. However, there is only moderate skill for this region in December. Elsewhere, climatological probabilities are predicted.

Overall, the models’ skill for rainfall are very good for the eastern and southern ASEAN region, the Philippines, with low to moderate skill elsewhere.

ncep_rain_rain_ANOM_1
Figure 1: Rainfall tercile summary predictions of NCEP model for December 2018.
icon
Figure 2: Rainfall tercile summary predictions of ECMWF model for December 2018 (contains modified Copernicus C3S information).
icon
Figure 3: Rainfall tercile summary predictions of UK Met Office model for December 2018 (contains modified Copernicus C3S information).
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.
Previous Next