Seasonal Forecast for January-February-March 2020

Updated 2 January 2020

Summary of Outlook

Climatologically, during the Northeast Monsoon period of January to March, the northern ASEAN region is in its traditional dry season with dry conditions persisting throughout. In contrast, the southern ASEAN region experiences its traditional rainy season that is typically rainy in January, and cool and dry in February. The prevailing winds during the January to March period typically blow from the northwest or northeast and gradually weakens around March, when the Northeast Monsoon conditions transition to inter-monsoon conditions.

Warmer than normal conditions are likely over most parts of Southeast Asia during the outlook period from January to March 2020. Based on the models, no significant deviation in rainfall trends is expected.

As the northern ASEAN dry season progresses, an escalation of hotspot activities and hazy conditions in the Mekong sub-region can be expected. In the southern ASEAN region, hotspot activities are expected to remain generally subdued due to the rainy weather, but occasional increase in hotspot activities can be expected in Sumatra, Kalimantan and Malaysia during periods of dry weather in February.

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.

For January 2020, for most of Southeast Asia, predictions either are not consistent across models, or have low skill. However, there is an increased chance of above-normal rainfall for parts of eastern Indonesia.

 

For January 2020, two models – NCEP CFSv2 and the UK Met Office (Figures 1a, 1c) favour an increased chance of above-normal rainfall for equatorial regions such as Sulawesi and Papua, while no dominant tercile is predicted by the ECMWF model (Figure 1b). The UK Met Office model suggests the wet region to extend further westwards to equatorial Borneo. This region where above-normal rainfall conditions are predicted broadly coincides with areas of low to moderate model skill. The area with the highest skill for this month is around the Philippines, but there is no dominant tercile predicted for this region from the models.

Elsewhere, the models show inconsistent forecasts or have limited skill (see the respective sections of “Model products and verification: NCEP, ECMWF, UK Met Office”).

Rainfall Tercile Summary of NCEP model.

Rainfall Tercile Summary of ECMWF model.

Figure 1a: Rainfall tercile summary predictions of NCEP model for January 2020. Figure 1b: Rainfall tercile summary predictions of ECMWF model for January 2020 (contains modified Copernicus C3S information).

Rainfall Tercile Summary of UK Met Office model.

Rainfall Tercile Summary of MME model.

Figure 1c: Rainfall tercile summary predictions of UK Met Office model for January 2020 (contains modified Copernicus C3S information). Figure 1d: Rainfall tercile summary predictions of multi-model ensemble model for January 2020 (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. More outlook and verification plots, including for tercile and quintile probabilistic forecasts for rainfall, are in the “Model products and verification: NCEP, ECMWF, UK Met Office” on the SEA-RCC Network LRF Node webpages.

 


For JFM 2020, climatological probabilities are predicted for the region, as there are no consistent predictions over land areas between the models for either above- or below-normal rainfall.

 

For JFM 2020, all three models – NCEP CFSv2, ECMWF and the UK Met Office (Figures 2a-c) – show no consistent or strong predictions over land areas for either above- or below-normal categories. There is a slightly higher chance for below-normal conditions for land areas in the western Maritime Continent and a higher chance for above-normal conditions for Sulawesi and Papua. The skill across models for the western Maritime Continent is moderate to high, while for Sulawesi and Paupa, the skill is low to moderate for this season (see the respective sections of “Model products and verification:NCEP, ECMWF, UK Met Office“).

Rainfall Tercile Summary of NCEP model.

Rainfall Tercile Summary of ECMWF model.

Figure 2a: Rainfall tercile summary predictions of NCEP model for JFM 2020. Figure 2b: Rainfall tercile summary predictions of ECMWF model for JFM 2020 (contains modified Copernicus C3S information).

Rainfall Tercile Summary of UK Met Office model.

Rainfall Tercile Summary of MME model.

Figure 2c: Rainfall tercile summary predictions of UK Met Office model for JFM 2020 (contains modified Copernicus C3S information). Figure 2d: Rainfall tercile summary predictions of multi-model ensemble model for JFM 2020 (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. More outlook and verification plots, including for tercile and quintile probabilistic forecasts for rainfall, are in the “Model products and verification: NCEP, ECMWF, UK Met Office” on the SEA-RCC Network LRF Node webpages.

For January 2020, above-normal temperature is favoured over most parts of Southeast Asia.

 

For January 2020, all three models – NCEP CFSv2, ECMWF and UK Met Office (Figures 1a-c) consistently predict a high likelihood of above-normal temperature conditions over most parts of Southeast Asia.

The models’ skill for predicting above-normal temperature tercile category are moderate to high over most parts of Southeast Asia except for the northern part of Mainland Southeast Asia (see the respective sections of “Model products and verification: NCEP, ECMWF, UK Met Office”).

Temperature tercile Summary of NCEP model.

Temperature tercile Summary of ECMWF model.

Figure 1a: Temperature tercile summary predictions of NCEP model for January 2020. Figure 1b: Temperature tercile summary predictions of ECMWF model for January 2020 (contains modified Copernicus C3S information).

Temperature tercile Summary of UK Met Office model.

Temperature tercile Summary of MME model.

Figure 1c: Temperature tercile summary predictions of UK Met Office model for January 2020 (contains modified Copernicus C3S information). Figure 1d: Temperature tercile summary predictions of multi-model ensemble model for January 2020 (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. More outlook and verification plots, including for tercile and quintile probabilistic forecasts for temperature, are in the “Model products and verification: NCEP, ECMWF, UK Met Office” on the SEA-RCC Network LRF Node webpages.


For JFM 2020, above-normal temperature is favoured over most parts of Southeast Asia.

 

For JFM 2020, all three models – NCEP CFSv2, ECMWF and UK Met Office (Figures 2 a-c) – favour above-normal temperature over most parts of Southeast Asia. These areas coincide with regions of moderate to high model skill except for northern parts of Mainland Southeast Asia (see the respective sections of “Model products and verification: NCEP, ECMWF, UK Met Office”).

Temperature tercile Summary of NCEP model.

Temperature tercile Summary of ECMWF model.

Figure 2a: Temperature tercile summary predictions of NCEP model for JFM 2020. Figure 2b: Temperature tercile summary predictions of ECMWF model for JFM 2020 (contains modified Copernicus C3S information).

Temperature tercile Summary of UK Met Office model.

Temperature tercile Summary of MME model.

Figure 2c: Temperature tercile summary predictions of UK Met Office model for JFM 2020 (contains modified Copernicus C3S information). Figure 2d: Temperature tercile summary predictions of multi-model ensemble model for JFM 2020 (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. More outlook and verification plots, including for tercile and quintile probabilistic forecasts for temperature, are in the “Model products and verification: NCEP, ECMWF, UK Met Office” on the SEA-RCC Network LRF Node webpages.