The Meteorological Department has warned that a typhoon will strike Thailand on Friday, resulting in heavy rain, sudden floods and landslides, with the Northeast expected to bear the brunt.
The department's deputy director-general and spokesman, Thanasit Iam-ananchai, on Tuesday said a depression in the northern part of the South China Sea was heading south and developing into a tropical storm.
"The storm is expected to enter Thailand's upper Northeast this Friday or sooner before stopping and then creating low-pressure areas," he said.
Mr Thanasit said the typhoon will first affect the eastern part of the Northeast.
He said it will hit the region's northern part the hardest, causing low-pressure areas in other parts of the Northeast and elsewhere, including the central, northern, and eastern regions. A strong southwest monsoon is likely to hit the South.
He said the storm will result in flash floods and landslides.
This comes after Typhoon Yagi caused chaos in northern Vietnam, Laos, Thailand and Myanmar, killing more than 500 people.
Meanwhile, flood warnings have been issued for five northeastern provinces where the rapidly rising Mekong River could burst its banks.
The Office of the National Water Resources said on Tuesday that a huge volume of floodwater was flowing downstream and could cause flooding this week in Bueng Kan, Nakhon Phanom, Mukdahan, Amnat Charoen and Ubon Ratchathani provinces.
Many parts of Nong Khai province have already been inundated by overflow from the swollen Mekong.
The municipal area in Muang district is among the worst flooded. All business there has been brought to a standstill over the past few days. The flood level is dropping, but the municipal office has advised residents to stay updated. Some parts of the town are still closed to traffic after the strong flood current eroded road surfaces.
In Nakhon Phanom, the Mekong continued to rise, but municipal mayor Niwat Chiawiriyabunya was hopeful they could keep the city dry.
He said the river's water level was still three metres below the crisis point.