Bangkok, The Meteorological Department warns the upper part of Thailand to prepare for heavy rain in some areas, which may cause flash floods and forest runoff.The Meteorological Department revealed that the monsoon trough is passing through the upper North and upper Laos, along with the southwest monsoon still blowing across the Andaman Sea, Thailand and the Gulf of Thailand. This condition will cause heavy rain in some areas of upper Thailand. People in the aforementioned areas should be careful of the dangers of heavy rain and accumulated rain, which may cause flash floods and forest runoff, especially in areas on hillsides near waterways and lowlands.For waves in the upper Andaman Sea, they are moderate with waves 1-2 meters high. In areas with thunderstorms, the waves are higher than 2 meters. For the lower Andaman Sea and the Gulf of Thailand, the waves are approximately 1 meter high. In areas with thunderstorms, the waves are higher than 1 meter. Sailors are asked to sail with caution and avoid sa iling in areas with thunderstorms.Source: Thai News Agency