General weather patterns
The weather outlook bulletins for the 3 months (Aug-Sep-Oct) and weather maps issued by the Thailand Meteorology Department (TMD) were used to verify the weather condition in the LMB. Since early August 2020, there were moderate rainfalls over the Lower Mekong Basin (LMB). The TMD expected of low pressures and tropical cyclones may move closer to the Mekong Region in August and continue to September which can bring heavy rainfall in the Mekong region. They also predicted of scattered to fairly widespread thundershowers with isolated heavy rain from August to September 2020. Figure 1 presented the weather map effected on 02 August 2020, which showed the Tropical Storm of SINLAKU moves slowly to West direction. Consequently, flash and forest flood with overflow will inundate at some areas, which need to follow the weather forecast news and tropical cyclone warnings by each National Hydrometeorological Center.
According to the Asian Specialized Meteorological Centre (ASMC), the increased shower rainfall over the Mekong sub-region, above-normal rainfall and hotspot activities will be happened in August and September 2020. In the southern ASEAN region, rainfall over most parts of the equatorial region is predicted to be above normal in August-September 2020.
Consequently, from August to September 2020, there will increasing chance of moderate rainfall to above average rainfall for most parts of the Asian countries especially in the Mekong region. Figure 2 showed the outlook of rainfall for 2 months from August to September 2020 in Southeast Asia, which showed the above-normal rainfall for the Mekong region.