Narathiwat province in the far South is bracing for a third round of severe floods over the next couple of days.
Heavy downpours look set to return at a time when the province is still reeling from previous flooding.
Weather in the South has been unusually wet over the the past couple of months.
Although the previous flooding showed signs of easing off with reduced water levels in the Sungai Kolok, Bang Nara and Saiburi rivers, residents remain nervous as they prepare for the latest round of heavy rain, according to Narathiwat governor Sitthichai Sakda.
Authorities said many locals were already struggling after the previous floods.
The latest inundation has led the entire province to be declared a disaster zone, which enables the immediate disbursement of a disaster budget to tackle flood-related problems, he said. In all, 145,000 residents have been affected by the floods in all 13 districts of Narathiwat.
Earlier, Trang province to the north of Narathiwat suffered a third round of flooding from the Trang River, affecting 400 houses in Muang district.
Meteorological Department chief Wanchai Sakudomchai has issued warnings for Nakhon Si Thammarat, Pattani, Yala and Narathiwat, which are already soaked, to stay alert for further heavy rainfall, especially Tuesday and Wednesday.
As a new cold front from China has sent the mercury tumbling by between 2 and 4 degrees Celsius in the North and Northeast, the southern region is predicted to experience a monsoon which promises more rain, according to Mr Wanchai.
Before the return of the heavy rain, floods were receding Monday in some areas in Narathiwat with some locals cleaning up.
The flood water in nine communities near the Sungai Kolok River had fallen to between 1 and 1.5 metres, but was still high which prevented many villagers, who had been evacuated to higher ground, from returning home, according to aerial images taken by a drone.
Meanwhile, the Royal Irrigation Department (RID) has asked for support in flood-affected areas for the department's water-management projects, including dam construction in flood-prone areas.
Narong Leenanon, the RID deputy chief, said some flood-prevention projects were stalled because of local opposition.
Dams could help with water retention and speeding water flow to the sea, even if they could not help prevent flooding entirely, he said.
