Subseasonal Weather Outlook (17 – 30 May 2021)
Issued 14 May 2021
First forecast week: 17 May – 23 May
Second forecast week: 24 May – 30 May
An increased chance of wetter conditions is expected over parts of the eastern Maritime Continent in Week 1 (17 – 23 May). Models are also predicting wetter conditions over southern Viet Nam and Cambodia, although with a lower confidence compared to the eastern Maritime Continent.
Drier conditions than usual are expected over much of northwestern Mainland Southeast Asia in Week 1 (17 – 23 May).
Warmer temperatures than usual are expected over much of northwestern Mainland Southeast Asia in Week 1 (17 – 23 May). These warmer temperatures are expected to ease and become confined mainly to northern parts of Myanmar and Lao PDR in Week 2 (24 – 30 May).
A weak Madden-Julian Oscillation (MJO) signal was present over the Indian Ocean (Phases 2 and 3). While the MJO signal is expected to be less coherent at the start of the forecast period, most models forecast the MJO to propagate eastwards and move into the Maritime Continent (Phase 4) by middle of Week 1. By end of May, some models predict the MJO to reach the Western Pacific (Phases 6 and 7).
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.