Subseasonal Weather Outlook and Review

Figure 1: Rainfall Outlook

Figure 2: Temperature Outlook

  Drier conditions are predicted over much of the southern Maritime
Continent in Week 1 (25 – 31 December 2023). Drier conditions are also
predicted over parts of the northeastern Maritime Continent in Week 1,
extending to the eastern coast of Mainland Southeast Asia in Week 2 (1 – 7
January 2024). Wetter conditions are predicted over parts of the western
Maritime continent in Week 1 (25 – 31 December 2023), extending eastwards to
Borneo in Week 2 (1 – 7 January 2024). Warmer than usual temperature is
predicted over most of the Maritime Continent during the next fortnight (25
December 2023 – 7 January 2024). Cooler than usual temperature is predicted
over much of central Mainland Southeast Asia in Week 1 (25 – 31 December
2023). A weak Madden-Julian Oscillation (MJO) signal was present over the
Western Hemisphere and Africa (Phases 8 and 1) at the start of the forecast
period. Most models predict the MJO signal to propagate through the Western
Hemisphere and Africa and reach the Indian Ocean (Phase 2) in Week 1, and then
weaken over the Indian Ocean (Phases 2 and 3) in Week 2.

The outlook is assessed for the region in general, where conditions are
relative to the average conditions for the corresponding time of year. For
specific updates on the national scale, the relevant ASEAN National
Meteorological and Hydrological Services should be consulted.

Figure 1: Rainfall Outlook

Figure 2: Temperature Outlook

  Drier conditions are predicted over much of the southern Maritime
Continent in Week 1 (25 – 31 December 2023). Drier conditions are also
predicted over parts of the northeastern Maritime Continent in Week 1,
extending to the eastern coast of Mainland Southeast Asia in Week 2 (1 – 7
January 2024). Wetter conditions are predicted over parts of the western
Maritime continent in Week 1 (25 – 31 December 2023), extending eastwards to
Borneo in Week 2 (1 – 7 January 2024). Warmer than usual temperature is
predicted over most of the Maritime Continent during the next fortnight (25
December 2023 – 7 January 2024). Cooler than usual temperature is predicted
over much of central Mainland Southeast Asia in Week 1 (25 – 31 December
2023). A weak Madden-Julian Oscillation (MJO) signal was present over the
Western Hemisphere and Africa (Phases 8 and 1) at the start of the forecast
period. Most models predict the MJO signal to propagate through the Western
Hemisphere and Africa and reach the Indian Ocean (Phase 2) in Week 1, and then
weaken over the Indian Ocean (Phases 2 and 3) in Week 2.

The outlook is assessed for the region in general, where conditions are
relative to the average conditions for the corresponding time of year. For
specific updates on the national scale, the relevant ASEAN National
Meteorological and Hydrological Services should be consulted.