During 11-12 Aug, Monsoon trough lies across the North and the upper Northeast and the southwest monsoon covers the Andaman Sea, the South and the Gulf of Thailand will weaken so likely less rain is over upper Thailand but the East and the South will have isolated heavy rain.
During 13-17 Aug, Monsoon trough lies across the upper Thailand and Laos and the southwest monsoon covers the Andaman Sea, the South and the Gulf of Thailand still weaken. It makes Thailand decreasing rain.