Rainfall
Seasonal Rainfall Outlook: January-March 2021 (JFM)
Issued: 24 Dec 2020
For JFM 2021, above-normal rainfall is predicted for eastern parts of the Maritime Continent and the southern Viet Nam.
For JFM 2021, all three models – NCEP, ECMWF, and UK Met Office (Figures 1-3) – predict an increased chance of above-normal rainfall over eastern parts of the Maritime Continent (apart from Sumatra, southwestern Borneo and Sulawesi where below- to near-normal rainfall is predicted) and southern Viet Nam. The model skill for the above-normal tercile category is moderate to relatively good for the northern Maritime Continent but low to moderate for the southern Maritime Continent. As for the three regions where below- to near-normal rainfall is predicted, the model skills are relatively moderate.
Elsewhere, the models show inconsistent forecasts (Peninsular Malaysia) or have low skill (Mainland Southeast Asia).
Figure 1: Rainfall tercile summary predictions of NCEP model for JFM 2021.
Figure 2: Rainfall tercile summary predictions of ECMWF model for JFM 2021 (contains modified Copernicus C3S information).
Figure 5: Average climatological rainfall's lower tercile boundary for JFM based on CHIRPS (Reference period: 1981-2010).
Figure 6: Average climatological rainfall's upper tercile boundary for JFM based on CHIRPS (Reference period: 1981-2010).
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.